ETH Price: $2,529.68 (+0.76%)

Transaction Decoder

Block:
18281178 at Oct-05-2023 01:57:59 AM +UTC
Transaction Fee:
0.000477621524001867 ETH $1.21
Gas Used:
62,489 Gas / 7.643289603 Gwei

Emitted Events:

89 Proxy.0xb3813568d9991fc951961fcb4c784893574240a28925604d09fc577c55bb7c32( 0xb3813568d9991fc951961fcb4c784893574240a28925604d09fc577c55bb7c32, 0x000000000000000000000000c4fb550fa8f2a6e5178711e56d5b48dedf897e5e, 0x000000000000000000000000c4fb550fa8f2a6e5178711e56d5b48dedf897e5e, 0x0000000000000000000000000000000000000000000000000000000000000000, 0000000000000000000000000000000000000000000000000000000000000020, 0000000000000000000000000000000000000000000000000000000000000049, 00000000000000000000000000000000000000000000000000354a6ba7a18000, 00000000000000000000000000000000000000000000000000354a6ba7a18000, 0000000000030d40000000000000000000000000000000000000000000000000 )

Account State Difference:

  Address   Before After State Difference Code
0x31F64857...C5F5558de
(Kroma: Portal)
163.654070444145513259 Eth163.669070444145513259 Eth0.015
(Titan Builder)
14.514898244470417198 Eth14.515008695336330369 Eth0.000110450865913171
0xc4fb550F...EdF897e5e
0.019313679584628492 Eth
Nonce: 1481
0.003836058060626625 Eth
Nonce: 1482
0.015477621524001867

Execution Trace

ETH 0.015 Proxy.e9e05c42( )
  • ETH 0.015 KromaPortal.depositTransaction( _to=0xc4fb550FA8F2A6e5178711e56D5b48DEdF897e5e, _value=15000000000000000, _gasLimit=200000, _isCreation=False, _data=0x )
    • Proxy.STATICCALL( )
      • SystemConfig.DELEGATECALL( )
        depositTransaction[KromaPortal (ln:379)]
        File 1 of 4: Proxy
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        /**
         * @title Proxy
         * @notice Proxy is a transparent proxy that passes through the call if the caller is the owner or
         *         if the caller is address(0), meaning that the call originated from an off-chain
         *         simulation.
         */
        contract Proxy {
            /**
             * @notice The storage slot that holds the address of the implementation.
             *         bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1)
             */
            bytes32 internal constant IMPLEMENTATION_KEY =
                0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
            /**
             * @notice The storage slot that holds the address of the owner.
             *         bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1)
             */
            bytes32 internal constant OWNER_KEY =
                0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
            /**
             * @notice An event that is emitted each time the implementation is changed. This event is part
             *         of the EIP-1967 specification.
             *
             * @param implementation The address of the implementation contract
             */
            event Upgraded(address indexed implementation);
            /**
             * @notice An event that is emitted each time the owner is upgraded. This event is part of the
             *         EIP-1967 specification.
             *
             * @param previousAdmin The previous owner of the contract
             * @param newAdmin      The new owner of the contract
             */
            event AdminChanged(address previousAdmin, address newAdmin);
            /**
             * @notice A modifier that reverts if not called by the owner or by address(0) to allow
             *         eth_call to interact with this proxy without needing to use low-level storage
             *         inspection. We assume that nobody is able to trigger calls from address(0) during
             *         normal EVM execution.
             */
            modifier proxyCallIfNotAdmin() {
                if (msg.sender == _getAdmin() || msg.sender == address(0)) {
                    _;
                } else {
                    // This WILL halt the call frame on completion.
                    _doProxyCall();
                }
            }
            /**
             * @notice Sets the initial admin during contract deployment. Admin address is stored at the
             *         EIP-1967 admin storage slot so that accidental storage collision with the
             *         implementation is not possible.
             *
             * @param _admin Address of the initial contract admin. Admin as the ability to access the
             *               transparent proxy interface.
             */
            constructor(address _admin) {
                _changeAdmin(_admin);
            }
            // slither-disable-next-line locked-ether
            receive() external payable {
                // Proxy call by default.
                _doProxyCall();
            }
            // slither-disable-next-line locked-ether
            fallback() external payable {
                // Proxy call by default.
                _doProxyCall();
            }
            /**
             * @notice Set the implementation contract address. The code at the given address will execute
             *         when this contract is called.
             *
             * @param _implementation Address of the implementation contract.
             */
            function upgradeTo(address _implementation) public virtual proxyCallIfNotAdmin {
                _setImplementation(_implementation);
            }
            /**
             * @notice Set the implementation and call a function in a single transaction. Useful to ensure
             *         atomic execution of initialization-based upgrades.
             *
             * @param _implementation Address of the implementation contract.
             * @param _data           Calldata to delegatecall the new implementation with.
             */
            function upgradeToAndCall(address _implementation, bytes calldata _data)
                public
                payable
                virtual
                proxyCallIfNotAdmin
                returns (bytes memory)
            {
                _setImplementation(_implementation);
                (bool success, bytes memory returndata) = _implementation.delegatecall(_data);
                require(success, "Proxy: delegatecall to new implementation contract failed");
                return returndata;
            }
            /**
             * @notice Changes the owner of the proxy contract. Only callable by the owner.
             *
             * @param _admin New owner of the proxy contract.
             */
            function changeAdmin(address _admin) public virtual proxyCallIfNotAdmin {
                _changeAdmin(_admin);
            }
            /**
             * @notice Gets the owner of the proxy contract.
             *
             * @return Owner address.
             */
            function admin() public virtual proxyCallIfNotAdmin returns (address) {
                return _getAdmin();
            }
            /**
             * @notice Queries the implementation address.
             *
             * @return Implementation address.
             */
            function implementation() public virtual proxyCallIfNotAdmin returns (address) {
                return _getImplementation();
            }
            /**
             * @notice Sets the implementation address.
             *
             * @param _implementation New implementation address.
             */
            function _setImplementation(address _implementation) internal {
                assembly {
                    sstore(IMPLEMENTATION_KEY, _implementation)
                }
                emit Upgraded(_implementation);
            }
            /**
             * @notice Changes the owner of the proxy contract.
             *
             * @param _admin New owner of the proxy contract.
             */
            function _changeAdmin(address _admin) internal {
                address previous = _getAdmin();
                assembly {
                    sstore(OWNER_KEY, _admin)
                }
                emit AdminChanged(previous, _admin);
            }
            /**
             * @notice Performs the proxy call via a delegatecall.
             */
            function _doProxyCall() internal {
                address impl = _getImplementation();
                require(impl != address(0), "Proxy: implementation not initialized");
                assembly {
                    // Copy calldata into memory at 0x0....calldatasize.
                    calldatacopy(0x0, 0x0, calldatasize())
                    // Perform the delegatecall, make sure to pass all available gas.
                    let success := delegatecall(gas(), impl, 0x0, calldatasize(), 0x0, 0x0)
                    // Copy returndata into memory at 0x0....returndatasize. Note that this *will*
                    // overwrite the calldata that we just copied into memory but that doesn't really
                    // matter because we'll be returning in a second anyway.
                    returndatacopy(0x0, 0x0, returndatasize())
                    // Success == 0 means a revert. We'll revert too and pass the data up.
                    if iszero(success) {
                        revert(0x0, returndatasize())
                    }
                    // Otherwise we'll just return and pass the data up.
                    return(0x0, returndatasize())
                }
            }
            /**
             * @notice Queries the implementation address.
             *
             * @return Implementation address.
             */
            function _getImplementation() internal view returns (address) {
                address impl;
                assembly {
                    impl := sload(IMPLEMENTATION_KEY)
                }
                return impl;
            }
            /**
             * @notice Queries the owner of the proxy contract.
             *
             * @return Owner address.
             */
            function _getAdmin() internal view returns (address) {
                address owner;
                assembly {
                    owner := sload(OWNER_KEY)
                }
                return owner;
            }
        }
        

        File 2 of 4: KromaPortal
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Initializable } from "@openzeppelin/contracts/proxy/utils/Initializable.sol";
        import { Constants } from "../libraries/Constants.sol";
        import { Hashing } from "../libraries/Hashing.sol";
        import { SafeCall } from "../libraries/SafeCall.sol";
        import { Types } from "../libraries/Types.sol";
        import { Semver } from "../universal/Semver.sol";
        import { AddressAliasHelper } from "../vendor/AddressAliasHelper.sol";
        import { L2OutputOracle } from "./L2OutputOracle.sol";
        import { ResourceMetering } from "./ResourceMetering.sol";
        import { SystemConfig } from "./SystemConfig.sol";
        import { ZKMerkleTrie } from "./ZKMerkleTrie.sol";
        /**
         * @custom:proxied
         * @title KromaPortal
         * @notice The KromaPortal is a low-level contract responsible for passing messages between L1
         *         and L2. Messages sent directly to the KromaPortal have no form of replayability.
         *         Users are encouraged to use the L1CrossDomainMessenger for a higher-level interface.
         */
        contract KromaPortal is Initializable, ResourceMetering, Semver {
            /**
             * @notice Represents a proven withdrawal.
             *
             * @custom:field outputRoot    Root of the L2 output this was proven against.
             * @custom:field timestamp     Timestamp at whcih the withdrawal was proven.
             * @custom:field l2OutputIndex Index of the output this was proven against.
             */
            struct ProvenWithdrawal {
                bytes32 outputRoot;
                uint128 timestamp;
                uint128 l2OutputIndex;
            }
            /**
             * @notice Version of the deposit event.
             */
            uint256 internal constant DEPOSIT_VERSION = 0;
            /**
             * @notice The L2 gas limit set when eth is deposited using the receive() function.
             */
            uint64 internal constant RECEIVE_DEFAULT_GAS_LIMIT = 100_000;
            /**
             * @notice Address of the L2OutputOracle contract.
             */
            L2OutputOracle public immutable L2_ORACLE;
            /**
             * @notice Address of the ValidatorPool contract.
             */
            address public immutable VALIDATOR_POOL;
            /**
            /**
             * @notice Address of the SystemConfig contract.
             */
            SystemConfig public immutable SYSTEM_CONFIG;
            /**
             * @notice MultiSig wallet address that has the ability to pause and unpause withdrawals.
             */
            address public immutable GUARDIAN;
            /**
             * @notice Address of the ZKMerkleTrie.
             */
            ZKMerkleTrie public immutable ZK_MERKLE_TRIE;
            /**
             * @notice Address of the L2 account which initiated a withdrawal in this transaction. If the
             *         of this variable is the default L2 sender address, then we are NOT inside of a call
             *         to finalizeWithdrawalTransaction.
             */
            address public l2Sender;
            /**
             * @notice A list of withdrawal hashes which have been successfully finalized.
             */
            mapping(bytes32 => bool) public finalizedWithdrawals;
            /**
             * @notice A mapping of withdrawal hashes to `ProvenWithdrawal` data.
             */
            mapping(bytes32 => ProvenWithdrawal) public provenWithdrawals;
            /**
             * @notice Determines if cross domain messaging is paused. When set to true,
             *         withdrawals are paused. This may be removed in the future.
             */
            bool public paused;
            /**
             * @notice Emitted when a transaction is deposited from L1 to L2. The parameters of this event
             *         are read by the rollup node and used to derive deposit transactions on L2.
             *
             * @param from       Address that triggered the deposit transaction.
             * @param to         Address that the deposit transaction is directed to.
             * @param version    Version of this deposit transaction event.
             * @param opaqueData ABI encoded deposit data to be parsed off-chain.
             */
            event TransactionDeposited(
                address indexed from,
                address indexed to,
                uint256 indexed version,
                bytes opaqueData
            );
            /**
             * @notice Emitted when a withdrawal transaction is proven.
             *
             * @param withdrawalHash Hash of the withdrawal transaction.
             */
            event WithdrawalProven(
                bytes32 indexed withdrawalHash,
                address indexed from,
                address indexed to
            );
            /**
             * @notice Emitted when a withdrawal transaction is finalized.
             *
             * @param withdrawalHash Hash of the withdrawal transaction.
             * @param success        Whether the withdrawal transaction was successful.
             */
            event WithdrawalFinalized(bytes32 indexed withdrawalHash, bool success);
            /**
             * @notice Emitted when the pause is triggered.
             *
             * @param account Address of the account triggering the pause.
             */
            event Paused(address account);
            /**
             * @notice Emitted when the pause is lifted.
             *
             * @param account Address of the account triggering the unpause.
             */
            event Unpaused(address account);
            /**
             * @notice Reverts when paused.
             */
            modifier whenNotPaused() {
                require(paused == false, "KromaPortal: paused");
                _;
            }
            /**
             * @custom:semver 1.0.0
             *
             * @param _l2Oracle                  Address of the L2OutputOracle contract.
             * @param _validatorPool             Address of the ValidatorPool contract.
             * @param _guardian                  MultiSig wallet address that can pause deposits and withdrawals.
             * @param _paused                    Sets the contract's pausability state.
             * @param _config                    Address of the SystemConfig contract.
             * @param _zkMerkleTrie              Address of the ZKMerkleTrie contract.
             */
            constructor(
                L2OutputOracle _l2Oracle,
                address _validatorPool,
                address _guardian,
                bool _paused,
                SystemConfig _config,
                ZKMerkleTrie _zkMerkleTrie
            ) Semver(1, 0, 0) {
                L2_ORACLE = _l2Oracle;
                VALIDATOR_POOL = _validatorPool;
                GUARDIAN = _guardian;
                SYSTEM_CONFIG = _config;
                ZK_MERKLE_TRIE = _zkMerkleTrie;
                initialize(_paused);
            }
            /**
             * @notice Initializer.
             */
            function initialize(bool _paused) public initializer {
                l2Sender = Constants.DEFAULT_L2_SENDER;
                paused = _paused;
                __ResourceMetering_init();
            }
            /**
             * @notice Pause deposits and withdrawals.
             */
            function pause() external {
                require(msg.sender == GUARDIAN, "KromaPortal: only guardian can pause");
                paused = true;
                emit Paused(msg.sender);
            }
            /**
             * @notice Unpause deposits and withdrawals.
             */
            function unpause() external {
                require(msg.sender == GUARDIAN, "KromaPortal: only guardian can unpause");
                paused = false;
                emit Unpaused(msg.sender);
            }
            /**
             * @notice Accepts value so that users can send ETH directly to this contract and have the
             *         funds be deposited to their address on L2. This is intended as a convenience
             *         function for EOAs. Contracts should call the depositTransaction() function directly
             *         otherwise any deposited funds will be lost due to address aliasing.
             */
            // solhint-disable-next-line ordering
            receive() external payable {
                depositTransaction(msg.sender, msg.value, RECEIVE_DEFAULT_GAS_LIMIT, false, bytes(""));
            }
            /**
             * @notice Getter for the resource config. Used internally by the ResourceMetering
             *         contract. The SystemConfig is the source of truth for the resource config.
             *
             * @return ResourceMetering.ResourceConfig
             */
            function _resourceConfig()
                internal
                view
                override
                returns (ResourceMetering.ResourceConfig memory)
            {
                return SYSTEM_CONFIG.resourceConfig();
            }
            /**
             * @notice Proves a withdrawal transaction.
             *
             * @param _tx              Withdrawal transaction to finalize.
             * @param _l2OutputIndex   L2 output index to prove against.
             * @param _outputRootProof Inclusion proof of the L2ToL1MessagePasser contract's storage root.
             * @param _withdrawalProof Inclusion proof of the withdrawal in L2ToL1MessagePasser contract.
             */
            function proveWithdrawalTransaction(
                Types.WithdrawalTransaction memory _tx,
                uint256 _l2OutputIndex,
                Types.OutputRootProof calldata _outputRootProof,
                bytes[] calldata _withdrawalProof
            ) external whenNotPaused {
                // Prevent users from creating a deposit transaction where this address is the message
                // sender on L2. Because this is checked here, we do not need to check again in
                // `finalizeWithdrawalTransaction`.
                require(
                    _tx.target != address(this),
                    "KromaPortal: you cannot send messages to the portal contract"
                );
                // Get the output root and load onto the stack to prevent multiple mloads. This will
                // revert if there is no output root for the given block number.
                bytes32 outputRoot = L2_ORACLE.getL2Output(_l2OutputIndex).outputRoot;
                // Verify that the output root can be generated with the elements in the proof.
                require(
                    outputRoot == Hashing.hashOutputRootProof(_outputRootProof),
                    "KromaPortal: invalid output root proof"
                );
                // Load the ProvenWithdrawal into memory, using the withdrawal hash as a unique identifier.
                bytes32 withdrawalHash = Hashing.hashWithdrawal(_tx);
                ProvenWithdrawal memory provenWithdrawal = provenWithdrawals[withdrawalHash];
                // We generally want to prevent users from proving the same withdrawal multiple times
                // because each successive proof will update the timestamp. A malicious user can take
                // advantage of this to prevent other users from finalizing their withdrawal. However,
                // since withdrawals are proven before an output root is finalized, we need to allow users
                // to re-prove their withdrawal only in the case that the output root for their specified
                // output index has been updated.
                require(
                    provenWithdrawal.timestamp == 0 ||
                        L2_ORACLE.getL2Output(provenWithdrawal.l2OutputIndex).outputRoot !=
                        provenWithdrawal.outputRoot,
                    "KromaPortal: withdrawal hash has already been proven"
                );
                // Compute the storage slot of the withdrawal hash in the L2ToL1MessagePasser contract.
                // Refer to the Solidity documentation for more information on how storage layouts are
                // computed for mappings.
                bytes32 storageKey = keccak256(
                    abi.encode(
                        withdrawalHash,
                        uint256(0) // The withdrawals mapping is at the first slot in the layout.
                    )
                );
                // Verify that the hash of this withdrawal was stored in the L2toL1MessagePasser contract
                // on L2. If this is true, under the assumption that the ZKMerkleTrie contract does not have
                // bugs, then we know that this withdrawal was actually triggered on L2 and can therefore
                // be relayed on L1.
                require(
                    ZK_MERKLE_TRIE.verifyInclusionProof(
                        storageKey,
                        hex"0000000000000000000000000000000000000000000000000000000000000001",
                        _withdrawalProof,
                        _outputRootProof.messagePasserStorageRoot
                    ),
                    "KromaPortal: invalid withdrawal inclusion proof"
                );
                // Designate the withdrawalHash as proven by storing the `outputRoot`, `timestamp`, and
                // `l2OutputIndex` in the `provenWithdrawals` mapping. A `withdrawalHash` can only be
                // proven once unless it is submitted again with a different outputRoot.
                provenWithdrawals[withdrawalHash] = ProvenWithdrawal({
                    outputRoot: outputRoot,
                    timestamp: uint128(block.timestamp),
                    l2OutputIndex: uint128(_l2OutputIndex)
                });
                // Emit a `WithdrawalProven` event.
                emit WithdrawalProven(withdrawalHash, _tx.sender, _tx.target);
            }
            /**
             * @notice Finalizes a withdrawal transaction.
             *
             * @param _tx Withdrawal transaction to finalize.
             */
            function finalizeWithdrawalTransaction(Types.WithdrawalTransaction memory _tx)
                external
                whenNotPaused
            {
                // Make sure that the l2Sender has not yet been set. The l2Sender is set to a value other
                // than the default value when a withdrawal transaction is being finalized. This check is
                // a defacto reentrancy guard.
                require(
                    l2Sender == Constants.DEFAULT_L2_SENDER,
                    "KromaPortal: can only trigger one withdrawal per transaction"
                );
                // Grab the proven withdrawal from the `provenWithdrawals` map.
                bytes32 withdrawalHash = Hashing.hashWithdrawal(_tx);
                ProvenWithdrawal memory provenWithdrawal = provenWithdrawals[withdrawalHash];
                // A withdrawal can only be finalized if it has been proven. We know that a withdrawal has
                // been proven at least once when its timestamp is non-zero. Unproven withdrawals will have
                // a timestamp of zero.
                require(provenWithdrawal.timestamp != 0, "KromaPortal: withdrawal has not been proven yet");
                // As a sanity check, we make sure that the proven withdrawal's timestamp is greater than
                // starting timestamp inside the L2OutputOracle. Not strictly necessary but extra layer of
                // safety against weird bugs in the proving step.
                require(
                    provenWithdrawal.timestamp >= L2_ORACLE.startingTimestamp(),
                    "KromaPortal: withdrawal timestamp less than L2 Oracle starting timestamp"
                );
                // A proven withdrawal must wait at least the finalization period before it can be
                // finalized. This waiting period can elapse in parallel with the waiting period for the
                // output the withdrawal was proven against. In effect, this means that the minimum
                // withdrawal time is l2 output submission time + finalization period.
                require(
                    _isFinalizationPeriodElapsed(provenWithdrawal.timestamp),
                    "KromaPortal: proven withdrawal finalization period has not elapsed"
                );
                // Grab the CheckpointOutput from the L2OutputOracle, will revert if the output that
                // corresponds to the given index has not been submitted yet.
                Types.CheckpointOutput memory checkpointOutput = L2_ORACLE.getL2Output(
                    provenWithdrawal.l2OutputIndex
                );
                // Check that the output root that was used to prove the withdrawal is the same as the
                // current output root for the given output index. An output root may change if it is
                // deleted by the challenger address and then re-submitted.
                require(
                    checkpointOutput.outputRoot == provenWithdrawal.outputRoot,
                    "KromaPortal: output root proven is not the same as current output root"
                );
                // Check that the checkpoint output has also been finalized.
                require(
                    _isFinalizationPeriodElapsed(checkpointOutput.timestamp),
                    "KromaPortal: checkpoint output finalization period has not elapsed"
                );
                // Check that this withdrawal has not already been finalized, this is replay protection.
                require(
                    finalizedWithdrawals[withdrawalHash] == false,
                    "KromaPortal: withdrawal has already been finalized"
                );
                // Mark the withdrawal as finalized so it can't be replayed.
                finalizedWithdrawals[withdrawalHash] = true;
                // Set the l2Sender so contracts know who triggered this withdrawal on L2.
                l2Sender = _tx.sender;
                // Trigger the call to the target contract. We use a custom low level method
                // SafeCall.callWithMinGas to ensure two key properties
                //   1. Target contracts cannot force this call to run out of gas by returning a very large
                //      amount of data (and this is OK because we don't care about the returndata here).
                //   2. The amount of gas provided to the execution context of the target is at least the
                //      gas limit specified by the user. If there is not enough gas in the current context
                //      to accomplish this, `callWithMinGas` will revert.
                bool success = SafeCall.callWithMinGas(_tx.target, _tx.gasLimit, _tx.value, _tx.data);
                // Reset the l2Sender back to the default value.
                l2Sender = Constants.DEFAULT_L2_SENDER;
                // All withdrawals are immediately finalized. Replayability can
                // be achieved through contracts built on top of this contract
                emit WithdrawalFinalized(withdrawalHash, success);
                // Reverting here is useful for determining the exact gas cost to successfully execute the
                // sub call to the target contract if the minimum gas limit specified by the user would not
                // be sufficient to execute the sub call.
                if (success == false && tx.origin == Constants.ESTIMATION_ADDRESS) {
                    revert("KromaPortal: withdrawal failed");
                }
            }
            /**
             * @notice Accepts deposits of ETH and data, and emits a TransactionDeposited event for use in
             *         deriving deposit transactions. Note that if a deposit is made by a contract, its
             *         address will be aliased when retrieved using `tx.origin` or `msg.sender`. Consider
             *         using the CrossDomainMessenger contracts for a simpler developer experience.
             *
             * @param _to         Target address on L2.
             * @param _value      ETH value to send to the recipient.
             * @param _gasLimit   Minimum L2 gas limit (can be greater than or equal to this value).
             * @param _isCreation Whether or not the transaction is a contract creation.
             * @param _data       Data to trigger the recipient with.
             */
            function depositTransaction(
                address _to,
                uint256 _value,
                uint64 _gasLimit,
                bool _isCreation,
                bytes memory _data
            ) public payable metered(_gasLimit) {
                // Just to be safe, make sure that people specify address(0) as the target when doing
                // contract creations.
                if (_isCreation) {
                    require(
                        _to == address(0),
                        "KromaPortal: must send to address(0) when creating a contract"
                    );
                }
                // Prevent depositing transactions that have too small of a gas limit.
                require(_gasLimit >= 21_000, "KromaPortal: gas limit must cover instrinsic gas cost");
                // Transform the from-address to its alias if the caller is a contract.
                address from = msg.sender;
                if (msg.sender != tx.origin) {
                    from = AddressAliasHelper.applyL1ToL2Alias(msg.sender);
                }
                // Compute the opaque data that will be emitted as part of the TransactionDeposited event.
                // We use opaque data so that we can update the TransactionDeposited event in the future
                // without breaking the current interface.
                bytes memory opaqueData = abi.encodePacked(
                    msg.value,
                    _value,
                    _gasLimit,
                    _isCreation,
                    _data
                );
                // Emit a TransactionDeposited event so that the rollup node can derive a deposit
                // transaction for this deposit.
                emit TransactionDeposited(from, _to, DEPOSIT_VERSION, opaqueData);
            }
            /**
             * @notice Accepts deposits of data from ValidatorPool contract, and emits a TransactionDeposited event for use in
             *         deriving deposit transactions on L2.
             *
             * @param _to         Target address on L2.
             * @param _gasLimit   Minimum L2 gas limit (can be greater than or equal to this value).
             * @param _data       Data to trigger the recipient with.
             */
            function depositTransactionByValidatorPool(
                address _to,
                uint64 _gasLimit,
                bytes memory _data
            ) public {
                require(
                    msg.sender == VALIDATOR_POOL,
                    "KromaPortal: function can only be called from the ValidatorPool"
                );
                // Transform the from-address to its alias.
                address from = AddressAliasHelper.applyL1ToL2Alias(msg.sender);
                // Compute the opaque data that will be emitted as part of the TransactionDeposited event.
                bytes memory opaqueData = abi.encodePacked(uint256(0), uint256(0), _gasLimit, false, _data);
                // Emit a TransactionDeposited event so that the rollup node can derive a deposit
                // transaction for this deposit.
                emit TransactionDeposited(from, _to, DEPOSIT_VERSION, opaqueData);
            }
            /**
             * @notice Determines if the output at the given index is finalized. Reverts if the call to
             *         L2_ORACLE.getL2Output reverts. Returns a boolean otherwise.
             *
             * @param _l2OutputIndex Index of the L2 output to check.
             *
             * @return Whether or not the output is finalized.
             */
            function isOutputFinalized(uint256 _l2OutputIndex) external view returns (bool) {
                return _isFinalizationPeriodElapsed(L2_ORACLE.getL2Output(_l2OutputIndex).timestamp);
            }
            /**
             * @notice Determines whether the finalization period has elapsed w/r/t a given timestamp.
             *
             * @param _timestamp Timestamp to check.
             *
             * @return Whether or not the finalization period has elapsed.
             */
            function _isFinalizationPeriodElapsed(uint256 _timestamp) internal view returns (bool) {
                return block.timestamp > _timestamp + L2_ORACLE.FINALIZATION_PERIOD_SECONDS();
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)
        pragma solidity ^0.8.2;
        import "../../utils/Address.sol";
        /**
         * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
         * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
         * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
         * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
         *
         * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
         * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
         * case an upgrade adds a module that needs to be initialized.
         *
         * For example:
         *
         * [.hljs-theme-light.nopadding]
         * ```solidity
         * contract MyToken is ERC20Upgradeable {
         *     function initialize() initializer public {
         *         __ERC20_init("MyToken", "MTK");
         *     }
         * }
         *
         * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
         *     function initializeV2() reinitializer(2) public {
         *         __ERC20Permit_init("MyToken");
         *     }
         * }
         * ```
         *
         * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
         * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
         *
         * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
         * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
         *
         * [CAUTION]
         * ====
         * Avoid leaving a contract uninitialized.
         *
         * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
         * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
         * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
         *
         * [.hljs-theme-light.nopadding]
         * ```
         * /// @custom:oz-upgrades-unsafe-allow constructor
         * constructor() {
         *     _disableInitializers();
         * }
         * ```
         * ====
         */
        abstract contract Initializable {
            /**
             * @dev Indicates that the contract has been initialized.
             * @custom:oz-retyped-from bool
             */
            uint8 private _initialized;
            /**
             * @dev Indicates that the contract is in the process of being initialized.
             */
            bool private _initializing;
            /**
             * @dev Triggered when the contract has been initialized or reinitialized.
             */
            event Initialized(uint8 version);
            /**
             * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
             * `onlyInitializing` functions can be used to initialize parent contracts.
             *
             * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
             * constructor.
             *
             * Emits an {Initialized} event.
             */
            modifier initializer() {
                bool isTopLevelCall = !_initializing;
                require(
                    (isTopLevelCall && _initialized < 1) || (!Address.isContract(address(this)) && _initialized == 1),
                    "Initializable: contract is already initialized"
                );
                _initialized = 1;
                if (isTopLevelCall) {
                    _initializing = true;
                }
                _;
                if (isTopLevelCall) {
                    _initializing = false;
                    emit Initialized(1);
                }
            }
            /**
             * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
             * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
             * used to initialize parent contracts.
             *
             * A reinitializer may be used after the original initialization step. This is essential to configure modules that
             * are added through upgrades and that require initialization.
             *
             * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
             * cannot be nested. If one is invoked in the context of another, execution will revert.
             *
             * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
             * a contract, executing them in the right order is up to the developer or operator.
             *
             * WARNING: setting the version to 255 will prevent any future reinitialization.
             *
             * Emits an {Initialized} event.
             */
            modifier reinitializer(uint8 version) {
                require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
                _initialized = version;
                _initializing = true;
                _;
                _initializing = false;
                emit Initialized(version);
            }
            /**
             * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
             * {initializer} and {reinitializer} modifiers, directly or indirectly.
             */
            modifier onlyInitializing() {
                require(_initializing, "Initializable: contract is not initializing");
                _;
            }
            /**
             * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
             * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
             * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
             * through proxies.
             *
             * Emits an {Initialized} event the first time it is successfully executed.
             */
            function _disableInitializers() internal virtual {
                require(!_initializing, "Initializable: contract is initializing");
                if (_initialized != type(uint8).max) {
                    _initialized = type(uint8).max;
                    emit Initialized(type(uint8).max);
                }
            }
            /**
             * @dev Returns the highest version that has been initialized. See {reinitializer}.
             */
            function _getInitializedVersion() internal view returns (uint8) {
                return _initialized;
            }
            /**
             * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
             */
            function _isInitializing() internal view returns (bool) {
                return _initializing;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        import { ResourceMetering } from "../L1/ResourceMetering.sol";
        /**
         * @title Constants
         * @notice Constants is a library for storing constants. Simple! Don't put everything in here, just
         *         the stuff used in multiple contracts. Constants that only apply to a single contract
         *         should be defined in that contract instead.
         */
        library Constants {
            /**
             * @notice Special address to be used as the tx origin for gas estimation calls in the
             *         KromaPortal and CrossDomainMessenger calls. You only need to use this address if
             *         the minimum gas limit specified by the user is not actually enough to execute the
             *         given message and you're attempting to estimate the actual necessary gas limit. We
             *         use address(1) because it's the ecrecover precompile and therefore guaranteed to
             *         never have any code on any EVM chain.
             */
            address internal constant ESTIMATION_ADDRESS = address(1);
            /**
             * @notice Value used for the L2 sender storage slot in both the KromaPortal and the
             *         CrossDomainMessenger contracts before an actual sender is set. This value is
             *         non-zero to reduce the gas cost of message passing transactions.
             */
            address internal constant DEFAULT_L2_SENDER = 0x000000000000000000000000000000000000dEaD;
            /**
             * @notice Returns the default values for the ResourceConfig. These are the recommended values
             *         for a production network.
             */
            function DEFAULT_RESOURCE_CONFIG()
                internal
                pure
                returns (ResourceMetering.ResourceConfig memory)
            {
                ResourceMetering.ResourceConfig memory config = ResourceMetering.ResourceConfig({
                    maxResourceLimit: 20_000_000,
                    elasticityMultiplier: 10,
                    baseFeeMaxChangeDenominator: 8,
                    minimumBaseFee: 1 gwei,
                    systemTxMaxGas: 1_000_000,
                    maximumBaseFee: type(uint128).max
                });
                return config;
            }
            /**
             * @notice The denominator of the validator reward.
             *         DO NOT change this value if the L2 chain is already operational.
             */
            uint256 internal constant VALIDATOR_REWARD_DENOMINATOR = 10000;
            /**
             * @notice An address that identifies that current submission round is a public round.
             */
            address internal constant VALIDATOR_PUBLIC_ROUND_ADDRESS = address(type(uint160).max);
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        import { Encoding } from "./Encoding.sol";
        import { RLPWriter } from "./rlp/RLPWriter.sol";
        import { Types } from "./Types.sol";
        /**
         * @title Hashing
         * @notice Hashing handles Kroma's various different hashing schemes.
         */
        library Hashing {
            /**
             * @notice Computes the hash of the RLP encoded L2 transaction that would be generated when a
             *         given deposit is sent to the L2 system. Useful for searching for a deposit in the L2
             *         system.
             *
             * @param _tx User deposit transaction to hash.
             *
             * @return Hash of the RLP encoded L2 deposit transaction.
             */
            function hashDepositTransaction(Types.UserDepositTransaction memory _tx)
                internal
                pure
                returns (bytes32)
            {
                return keccak256(Encoding.encodeDepositTransaction(_tx));
            }
            /**
             * @notice Computes the deposit transaction's "source hash", a value that guarantees the hash
             *         of the L2 transaction that corresponds to a deposit is unique and is
             *         deterministically generated from L1 transaction data.
             *
             * @param _l1BlockHash Hash of the L1 block where the deposit was included.
             * @param _logIndex    The index of the log that created the deposit transaction.
             *
             * @return Hash of the deposit transaction's "source hash".
             */
            function hashDepositSource(bytes32 _l1BlockHash, uint64 _logIndex)
                internal
                pure
                returns (bytes32)
            {
                bytes32 depositId = keccak256(abi.encode(_l1BlockHash, _logIndex));
                return keccak256(abi.encode(bytes32(0), depositId));
            }
            /**
             * @notice Hashes the cross domain message based on the version that is encoded into the
             *         message nonce.
             *
             * @param _nonce    Message nonce with version encoded into the first two bytes.
             * @param _sender   Address of the sender of the message.
             * @param _target   Address of the target of the message.
             * @param _value    ETH value to send to the target.
             * @param _gasLimit Gas limit to use for the message.
             * @param _data     Data to send with the message.
             *
             * @return Hashed cross domain message.
             */
            function hashCrossDomainMessage(
                uint256 _nonce,
                address _sender,
                address _target,
                uint256 _value,
                uint256 _gasLimit,
                bytes memory _data
            ) internal pure returns (bytes32) {
                (, uint16 version) = Encoding.decodeVersionedNonce(_nonce);
                if (version == 0) {
                    return hashCrossDomainMessageV0(_nonce, _sender, _target, _value, _gasLimit, _data);
                } else {
                    revert("Hashing: unknown cross domain message version");
                }
            }
            /**
             * @notice Hashes a cross domain message based on the V0 (current) encoding.
             *
             * @param _nonce    Message nonce.
             * @param _sender   Address of the sender of the message.
             * @param _target   Address of the target of the message.
             * @param _value    ETH value to send to the target.
             * @param _gasLimit Gas limit to use for the message.
             * @param _data     Data to send with the message.
             *
             * @return Hashed cross domain message.
             */
            function hashCrossDomainMessageV0(
                uint256 _nonce,
                address _sender,
                address _target,
                uint256 _value,
                uint256 _gasLimit,
                bytes memory _data
            ) internal pure returns (bytes32) {
                return
                    keccak256(
                        Encoding.encodeCrossDomainMessageV0(
                            _nonce,
                            _sender,
                            _target,
                            _value,
                            _gasLimit,
                            _data
                        )
                    );
            }
            /**
             * @notice Derives the withdrawal hash according to the encoding in the L2 Withdrawer contract
             *
             * @param _tx Withdrawal transaction to hash.
             *
             * @return Hashed withdrawal transaction.
             */
            function hashWithdrawal(Types.WithdrawalTransaction memory _tx)
                internal
                pure
                returns (bytes32)
            {
                return
                    keccak256(
                        abi.encode(_tx.nonce, _tx.sender, _tx.target, _tx.value, _tx.gasLimit, _tx.data)
                    );
            }
            /**
             * @notice Hashes the various elements of an output root proof into an output root hash which
             *         can be used to check if the proof is valid.
             *
             * @param _outputRootProof Output root proof which should be hashed to an output root.
             *
             * @return Hashed output root proof.
             */
            function hashOutputRootProof(Types.OutputRootProof memory _outputRootProof)
                internal
                pure
                returns (bytes32)
            {
                if (_outputRootProof.version == bytes32(uint256(0))) {
                    return hashOutputRootProofV0(_outputRootProof);
                } else {
                    revert("Hashing: unknown output root proof version");
                }
            }
            /**
             * @notice Hashes the various elements of an output root proof into an output root hash which
             *         can be used to check if the proof is valid. (version 0)
             *
             * @param _outputRootProof Output root proof which should be hashed to an output root.
             *
             * @return Hashed output root proof.
             */
            function hashOutputRootProofV0(Types.OutputRootProof memory _outputRootProof)
                internal
                pure
                returns (bytes32)
            {
                return
                    keccak256(
                        abi.encode(
                            _outputRootProof.version,
                            _outputRootProof.stateRoot,
                            _outputRootProof.messagePasserStorageRoot,
                            _outputRootProof.blockHash,
                            _outputRootProof.nextBlockHash
                        )
                    );
            }
            /**
             * @notice Fills the values of the block hash fields to a given bytes.
             *
             * @param _publicInput Public input which should be hashed to a block hash.
             * @param _rlps        Pre-RLP encoded data which should be hashed to a block hash.
             * @param _raw         An array of bytes to be populated.
             */
            function _fillBlockHashFieldsToBytes(
                Types.PublicInput memory _publicInput,
                Types.BlockHeaderRLP memory _rlps,
                bytes[] memory _raw
            ) private pure {
                _raw[0] = RLPWriter.writeBytes(abi.encodePacked(_publicInput.parentHash));
                _raw[1] = _rlps.uncleHash;
                _raw[2] = _rlps.coinbase;
                _raw[3] = RLPWriter.writeBytes(abi.encodePacked(_publicInput.stateRoot));
                _raw[4] = RLPWriter.writeBytes(abi.encodePacked(_publicInput.transactionsRoot));
                _raw[5] = _rlps.receiptsRoot;
                _raw[6] = _rlps.logsBloom;
                _raw[7] = _rlps.difficulty;
                _raw[8] = RLPWriter.writeUint(_publicInput.number);
                _raw[9] = RLPWriter.writeUint(_publicInput.gasLimit);
                _raw[10] = _rlps.gasUsed;
                _raw[11] = RLPWriter.writeUint(_publicInput.timestamp);
                _raw[12] = _rlps.extraData;
                _raw[13] = _rlps.mixHash;
                _raw[14] = _rlps.nonce;
                _raw[15] = RLPWriter.writeUint(_publicInput.baseFee);
            }
            /**
             * @notice Hashes the various elements of a block header into a block hash(before shanghai).
             *
             * @param _publicInput Public input which should be hashed to a block hash.
             * @param _rlps        Pre-RLP encoded data which should be hashed to a block hash.
             *
             * @return Hashed block header.
             */
            function hashBlockHeader(
                Types.PublicInput memory _publicInput,
                Types.BlockHeaderRLP memory _rlps
            ) internal pure returns (bytes32) {
                bytes[] memory raw = new bytes[](16);
                _fillBlockHashFieldsToBytes(_publicInput, _rlps, raw);
                return keccak256(RLPWriter.writeList(raw));
            }
            /**
             * @notice Hashes the various elements of a block header into a block hash(after shanghai).
             *
             * @param _publicInput Public input which should be hashed to a block hash.
             * @param _rlps        Pre-RLP encoded data which should be hashed to a block hash.
             *
             * @return Hashed block header.
             */
            function hashBlockHeaderShanghai(
                Types.PublicInput memory _publicInput,
                Types.BlockHeaderRLP memory _rlps
            ) internal pure returns (bytes32) {
                bytes[] memory raw = new bytes[](17);
                _fillBlockHashFieldsToBytes(_publicInput, _rlps, raw);
                raw[16] = RLPWriter.writeBytes(abi.encodePacked(_publicInput.withdrawalsRoot));
                return keccak256(RLPWriter.writeList(raw));
            }
            /**
             * @notice Hashes the various elements of a public input into a public input hash.
             *
             * @param _prevStateRoot Previous state root.
             * @param _publicInput   Public input which should be hashed to a public input hash.
             * @param _dummyHashes   Dummy hashes returned from generateDummyHashes().
             *
             * @return Hashed block header.
             */
            function hashPublicInput(
                bytes32 _prevStateRoot,
                Types.PublicInput memory _publicInput,
                bytes32[] memory _dummyHashes
            ) internal pure returns (bytes32) {
                return
                    keccak256(
                        abi.encodePacked(
                            _prevStateRoot,
                            _publicInput.stateRoot,
                            _publicInput.withdrawalsRoot,
                            _publicInput.blockHash,
                            _publicInput.parentHash,
                            _publicInput.number,
                            _publicInput.timestamp,
                            _publicInput.baseFee,
                            _publicInput.gasLimit,
                            uint16(_publicInput.txHashes.length),
                            _publicInput.txHashes,
                            _dummyHashes
                        )
                    );
            }
            /**
             * @notice Generates a bytes32 array filled with a dummy hash for the given length.
             *
             * @param _dummyHashes Dummy hash.
             * @param _length      A length of the array.
             *
             * @return Bytes32 array filled with dummy hash.
             */
            function generateDummyHashes(bytes32 _dummyHashes, uint256 _length)
                internal
                pure
                returns (bytes32[] memory)
            {
                bytes32[] memory hashes = new bytes32[](_length);
                for (uint256 i = 0; i < _length; i++) {
                    hashes[i] = _dummyHashes;
                }
                return hashes;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        /**
         * @title SafeCall
         * @notice Perform low level safe calls
         */
        library SafeCall {
            /**
             * @notice Perform a low level call without copying any returndata
             *
             * @param _target   Address to call
             * @param _gas      Amount of gas to pass to the call
             * @param _value    Amount of value to pass to the call
             * @param _calldata Calldata to pass to the call
             */
            function call(
                address _target,
                uint256 _gas,
                uint256 _value,
                bytes memory _calldata
            ) internal returns (bool) {
                bool _success;
                assembly {
                    _success := call(
                        _gas, // gas
                        _target, // recipient
                        _value, // ether value
                        add(_calldata, 32), // inloc
                        mload(_calldata), // inlen
                        0, // outloc
                        0 // outlen
                    )
                }
                return _success;
            }
            /**
             * @notice Helper function to determine if there is sufficient gas remaining within the context
             *         to guarantee that the minimum gas requirement for a call will be met as well as
             *         optionally reserving a specified amount of gas for after the call has concluded.
             *
             * @param _minGas      The minimum amount of gas that may be passed to the target context.
             * @param _reservedGas Optional amount of gas to reserve for the caller after the execution
             *                     of the target context.
             *
             * @return `true` if there is enough gas remaining to safely supply `_minGas` to the target
             *         context as well as reserve `_reservedGas` for the caller after the execution of
             *         the target context.
             *
             * @dev !!!!! FOOTGUN ALERT !!!!!
             *      1.) The 40_000 base buffer is to account for the worst case of the dynamic cost of the
             *          `CALL` opcode's `address_access_cost`, `positive_value_cost`, and
             *          `value_to_empty_account_cost` factors with an added buffer of 5,700 gas. It is
             *          still possible to self-rekt by initiating a withdrawal with a minimum gas limit
             *          that does not account for the `memory_expansion_cost` & `code_execution_cost`
             *          factors of the dynamic cost of the `CALL` opcode.
             *      2.) This function should *directly* precede the external call if possible. There is an
             *          added buffer to account for gas consumed between this check and the call, but it
             *          is only 5,700 gas.
             *      3.) Because EIP-150 ensures that a maximum of 63/64ths of the remaining gas in the call
             *          frame may be passed to a subcontext, we need to ensure that the gas will not be
             *          truncated.
             *      4.) Use wisely. This function is not a silver bullet.
             */
            function hasMinGas(uint256 _minGas, uint256 _reservedGas) internal view returns (bool) {
                bool _hasMinGas;
                assembly {
                    // Equation: gas × 63 ≥ minGas × 64 + 63(40_000 + reservedGas)
                    _hasMinGas := iszero(
                        lt(mul(gas(), 63), add(mul(_minGas, 64), mul(add(40000, _reservedGas), 63)))
                    )
                }
                return _hasMinGas;
            }
            /**
             * @notice Perform a low level call without copying any returndata. This function
             *         will revert if the call cannot be performed with the specified minimum
             *         gas.
             *
             * @param _target   Address to call
             * @param _minGas   The minimum amount of gas that may be passed to the call
             * @param _value    Amount of value to pass to the call
             * @param _calldata Calldata to pass to the call
             */
            function callWithMinGas(
                address _target,
                uint256 _minGas,
                uint256 _value,
                bytes memory _calldata
            ) internal returns (bool) {
                bool _success;
                bool _hasMinGas = hasMinGas(_minGas, 0);
                assembly {
                    // Assertion: gasleft() >= (_minGas * 64) / 63 + 40_000
                    if iszero(_hasMinGas) {
                        // Store the "Error(string)" selector in scratch space.
                        mstore(0, 0x08c379a0)
                        // Store the pointer to the string length in scratch space.
                        mstore(32, 32)
                        // Store the string.
                        //
                        // SAFETY:
                        // - We pad the beginning of the string with two zero bytes as well as the
                        // length (24) to ensure that we override the free memory pointer at offset
                        // 0x40. This is necessary because the free memory pointer is likely to
                        // be greater than 1 byte when this function is called, but it is incredibly
                        // unlikely that it will be greater than 3 bytes. As for the data within
                        // 0x60, it is ensured that it is 0 due to 0x60 being the zero offset.
                        // - It's fine to clobber the free memory pointer, we're reverting.
                        mstore(88, 0x0000185361666543616c6c3a204e6f7420656e6f75676820676173)
                        // Revert with 'Error("SafeCall: Not enough gas")'
                        revert(28, 100)
                    }
                    // The call will be supplied at least ((_minGas * 64) / 63 + 40_000 - 49) gas due to the
                    // above assertion. This ensures that, in all circumstances (except for when the
                    // `_minGas` does not account for the `memory_expansion_cost` and `code_execution_cost`
                    // factors of the dynamic cost of the `CALL` opcode), the call will receive at least
                    // the minimum amount of gas specified.
                    _success := call(
                        gas(), // gas
                        _target, // recipient
                        _value, // ether value
                        add(_calldata, 32), // inloc
                        mload(_calldata), // inlen
                        0x00, // outloc
                        0x00 // outlen
                    )
                }
                return _success;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.9;
        /**
         * @title Types
         * @notice Contains various types used throughout the Kroma contract system.
         */
        library Types {
            /**
             * @notice CheckpointOutput represents a commitment to the state of L2 checkpoint. The timestamp
             *         is the L1 timestamp that the output root is posted. This timestamp is used to verify
             *         that the finalization period has passed since the output root was submitted.
             *
             * @custom:field submitter     Address of the output submitter.
             * @custom:field outputRoot    Hash of the L2 output.
             * @custom:field timestamp     Timestamp of the L1 block that the output root was submitted in.
             * @custom:field l2BlockNumber L2 block number that the output corresponds to.
             */
            struct CheckpointOutput {
                address submitter;
                bytes32 outputRoot;
                uint128 timestamp;
                uint128 l2BlockNumber;
            }
            /**
             * @notice Struct representing the elements that are hashed together to generate an output root
             *         which itself represents a snapshot of the L2 state.
             *
             * @custom:field version                  Version of the output root.
             * @custom:field stateRoot                Root of the state trie at the block of this output.
             * @custom:field messagePasserStorageRoot Root of the message passer storage trie.
             * @custom:field blockHash                Hash of the block this output was generated from.
             * @custom:field nextBlockHash            Hash of the next block.
             */
            struct OutputRootProof {
                bytes32 version;
                bytes32 stateRoot;
                bytes32 messagePasserStorageRoot;
                bytes32 blockHash;
                bytes32 nextBlockHash;
            }
            /**
             * @notice Struct representing the elements that are hashed together to generate a public input.
             *
             * @custom:field blockHash        The hash of the block.
             * @custom:field parentHash       The hash of the previous block.
             * @custom:field timestamp        The block time.
             * @custom:field number           The block number.
             * @custom:field gasLimit         Maximum gas allowed.
             * @custom:field baseFee          The base fee per gas.
             * @custom:field transactionsRoot Root hash of the transactions.
             * @custom:field stateRoot        Root hash of the state trie.
             * @custom:field withdrawalsRoot  Root hash of the withdrawals.
             * @custom:field txHashes         Array of hash of the transaction.
             */
            struct PublicInput {
                bytes32 blockHash;
                bytes32 parentHash;
                uint64 timestamp;
                uint64 number;
                uint64 gasLimit;
                uint256 baseFee;
                bytes32 transactionsRoot;
                bytes32 stateRoot;
                bytes32 withdrawalsRoot;
                bytes32[] txHashes;
            }
            /**
             * @notice Struct representing the elements that are hashed together to generate a block hash.
             *         Some of fields that are contained in PublicInput are omitted.
             *
             * @custom:field uncleHash    RLP encoded uncle hash.
             * @custom:field coinbase     RLP encoded coinbase.
             * @custom:field receiptsRoot RLP encoded receipts root.
             * @custom:field logsBloom    RLP encoded logs bloom.
             * @custom:field difficulty   RLP encoded difficulty.
             * @custom:field gasUsed      RLP encoded gas used.
             * @custom:field extraData    RLP encoded extra data.
             * @custom:field mixHash      RLP encoded mix hash.
             * @custom:field nonce        RLP encoded nonce.
             */
            struct BlockHeaderRLP {
                bytes uncleHash;
                bytes coinbase;
                bytes receiptsRoot;
                bytes logsBloom;
                bytes difficulty;
                bytes gasUsed;
                bytes extraData;
                bytes mixHash;
                bytes nonce;
            }
            /**
             * @notice Struct representing a deposit transaction (L1 => L2 transaction) created by an end
             *         user (as opposed to a system deposit transaction generated by the system).
             *
             * @custom:field from        Address of the sender of the transaction.
             * @custom:field to          Address of the recipient of the transaction.
             * @custom:field isCreation  True if the transaction is a contract creation.
             * @custom:field value       Value to send to the recipient.
             * @custom:field mint        Amount of ETH to mint.
             * @custom:field gasLimit    Gas limit of the transaction.
             * @custom:field data        Data of the transaction.
             * @custom:field l1BlockHash Hash of the block the transaction was submitted in.
             * @custom:field logIndex    Index of the log in the block the transaction was submitted in.
             */
            struct UserDepositTransaction {
                address from;
                address to;
                bool isCreation;
                uint256 value;
                uint256 mint;
                uint64 gasLimit;
                bytes data;
                bytes32 l1BlockHash;
                uint64 logIndex;
            }
            /**
             * @notice Struct representing a withdrawal transaction.
             *
             * @custom:field nonce    Nonce of the withdrawal transaction
             * @custom:field sender   Address of the sender of the transaction.
             * @custom:field target   Address of the recipient of the transaction.
             * @custom:field value    Value to send to the recipient.
             * @custom:field gasLimit Gas limit of the transaction.
             * @custom:field data     Data of the transaction.
             */
            struct WithdrawalTransaction {
                uint256 nonce;
                address sender;
                address target;
                uint256 value;
                uint256 gasLimit;
                bytes data;
            }
            /**
             * @notice Struct representing a challenge.
             *
             * @custom:field turn       The current turn.
             * @custom:field timeoutAt  Timeout timestamp of the next turn.
             * @custom:field asserter   Address of the asserter.
             * @custom:field challenger Address of the challenger.
             * @custom:field segments   Array of the segment.
             * @custom:field segStart   The L2 block number of the first segment.
             * @custom:field segSize    The number of L2 blocks.
             */
            struct Challenge {
                uint8 turn;
                uint64 timeoutAt;
                address asserter;
                address challenger;
                bytes32[] segments;
                uint256 segSize;
                uint256 segStart;
            }
            /**
             * @notice Struct representing a validator's bond.
             *
             * @custom:field amount    Amount of the lock.
             * @custom:field expiresAt The expiration timestamp of bond.
             */
            struct Bond {
                uint128 amount;
                uint128 expiresAt;
            }
            /**
             * @notice Struct representing multisig transaction data.
             *
             * @custom:field destination The destination address to run the transaction.
             * @custom:field executed    Record whether a transaction was executed or not.
             * @custom:field value       The value passed in while executing the transaction.
             * @custom:field data        Calldata for transaction.
             */
            struct MultiSigTransaction {
                address destination;
                bool executed;
                uint256 value;
                bytes data;
            }
            /**
             * @notice Struct representing the data for verifying the public input.
             *
             * @custom:field srcOutputRootProof          Proof of the source output root.
             * @custom:field dstOutputRootProof          Proof of the destination output root.
             * @custom:field publicInput                 Ingredients to compute the public input used by ZK proof verification.
             * @custom:field rlps                        Pre-encoded RLPs to compute the next block hash
             *                                           of the source output root proof.
             * @custom:field l2ToL1MessagePasserBalance  Balance of the L2ToL1MessagePasser account.
             * @custom:field l2ToL1MessagePasserCodeHash Codehash of the L2ToL1MessagePasser account.
             * @custom:field merkleProof                 Merkle proof of L2ToL1MessagePasser account against the state root.
             */
            struct PublicInputProof {
                OutputRootProof srcOutputRootProof;
                OutputRootProof dstOutputRootProof;
                PublicInput publicInput;
                BlockHeaderRLP rlps;
                bytes32 l2ToL1MessagePasserBalance;
                bytes32 l2ToL1MessagePasserCodeHash;
                bytes[] merkleProof;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.15;
        import { Strings } from "@openzeppelin/contracts/utils/Strings.sol";
        /**
         * @title Semver
         * @notice Semver is a simple contract for managing contract versions.
         */
        contract Semver {
            /**
             * @notice Contract version number (major).
             */
            uint256 private immutable MAJOR_VERSION;
            /**
             * @notice Contract version number (minor).
             */
            uint256 private immutable MINOR_VERSION;
            /**
             * @notice Contract version number (patch).
             */
            uint256 private immutable PATCH_VERSION;
            /**
             * @param _major Version number (major).
             * @param _minor Version number (minor).
             * @param _patch Version number (patch).
             */
            constructor(
                uint256 _major,
                uint256 _minor,
                uint256 _patch
            ) {
                MAJOR_VERSION = _major;
                MINOR_VERSION = _minor;
                PATCH_VERSION = _patch;
            }
            /**
             * @notice Returns the full semver contract version.
             *
             * @return Semver contract version as a string.
             */
            function version() public view virtual returns (string memory) {
                return
                    string(
                        abi.encodePacked(
                            Strings.toString(MAJOR_VERSION),
                            ".",
                            Strings.toString(MINOR_VERSION),
                            ".",
                            Strings.toString(PATCH_VERSION)
                        )
                    );
            }
        }
        // SPDX-License-Identifier: Apache-2.0
        /*
         * Copyright 2019-2021, Offchain Labs, Inc.
         *
         * Licensed under the Apache License, Version 2.0 (the "License");
         * you may not use this file except in compliance with the License.
         * You may obtain a copy of the License at
         *
         *    http://www.apache.org/licenses/LICENSE-2.0
         *
         * Unless required by applicable law or agreed to in writing, software
         * distributed under the License is distributed on an "AS IS" BASIS,
         * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
         * See the License for the specific language governing permissions and
         * limitations under the License.
         */
        pragma solidity ^0.8.0;
        library AddressAliasHelper {
            uint160 constant offset = uint160(0x1111000000000000000000000000000000001111);
            /// @notice Utility function that converts the address in the L1 that submitted a tx to
            /// the inbox to the msg.sender viewed in the L2
            /// @param l1Address the address in the L1 that triggered the tx to L2
            /// @return l2Address L2 address as viewed in msg.sender
            function applyL1ToL2Alias(address l1Address) internal pure returns (address l2Address) {
                unchecked {
                    l2Address = address(uint160(l1Address) + offset);
                }
            }
            /// @notice Utility function that converts the msg.sender viewed in the L2 to the
            /// address in the L1 that submitted a tx to the inbox
            /// @param l2Address L2 address as viewed in msg.sender
            /// @return l1Address the address in the L1 that triggered the tx to L2
            function undoL1ToL2Alias(address l2Address) internal pure returns (address l1Address) {
                unchecked {
                    l1Address = address(uint160(l2Address) - offset);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Initializable } from "@openzeppelin/contracts/proxy/utils/Initializable.sol";
        import { Constants } from "../libraries/Constants.sol";
        import { Types } from "../libraries/Types.sol";
        import { Semver } from "../universal/Semver.sol";
        import { ValidatorPool } from "./ValidatorPool.sol";
        /**
         * @custom:proxied
         * @title L2OutputOracle
         * @notice The L2OutputOracle contains an array of L2 state outputs, where each output is a
         *         commitment to the state of the L2 chain. Other contracts like the KromaPortal use
         *         these outputs to verify information about the state of L2.
         */
        contract L2OutputOracle is Initializable, Semver {
            /**
             * @notice The address of the validator pool contract. Can be updated via upgrade.
             */
            ValidatorPool public immutable VALIDATOR_POOL;
            /**
             * @notice The address of the colosseum contract. Can be updated via upgrade.
             */
            address public immutable COLOSSEUM;
            /**
             * @notice The interval in L2 blocks at which checkpoints must be submitted. Although this is
             *         immutable, it can be modified by upgrading the implementation contract.
             *         Note that nodes that fetch and use this value need to restart when it is modified.
             */
            uint256 public immutable SUBMISSION_INTERVAL;
            /**
             * @notice The time between L2 blocks in seconds. Once set, this value MUST NOT be modified.
             */
            uint256 public immutable L2_BLOCK_TIME;
            /**
             * @notice Minimum time (in seconds) that must elapse before a withdrawal can be finalized.
             */
            uint256 public immutable FINALIZATION_PERIOD_SECONDS;
            /**
             * @notice The number of the first L2 block recorded in this contract.
             */
            uint256 public startingBlockNumber;
            /**
             * @notice The timestamp of the first L2 block recorded in this contract.
             */
            uint256 public startingTimestamp;
            /**
             * @notice Array of L2 checkpoint outputs.
             */
            Types.CheckpointOutput[] internal l2Outputs;
            /**
             * @notice Emitted when an output is submitted.
             *
             * @param outputRoot    The output root.
             * @param l2OutputIndex The index of the output in the l2Outputs array.
             * @param l2BlockNumber The L2 block number of the output root.
             * @param l1Timestamp   The L1 timestamp when submitted.
             */
            event OutputSubmitted(
                bytes32 indexed outputRoot,
                uint256 indexed l2OutputIndex,
                uint256 indexed l2BlockNumber,
                uint256 l1Timestamp
            );
            /**
             * @notice Emitted when an output is replaced.
             *
             * @param outputIndex   Replaced L2 output index.
             * @param newOutputRoot L2 output root after replacement.
             */
            event OutputReplaced(uint256 indexed outputIndex, bytes32 newOutputRoot);
            /**
             * @custom:semver 1.0.0
             *
             * @param _validatorPool             The address of the ValidatorPool contract.
             * @param _colosseum                 The address of the Colosseum contract.
             * @param _submissionInterval        Interval in blocks at which checkpoints must be submitted.
             * @param _l2BlockTime               The time per L2 block, in seconds.
             * @param _startingBlockNumber       The number of the first L2 block.
             * @param _startingTimestamp         The timestamp of the first L2 block.
             * @param _finalizationPeriodSeconds Output finalization time in seconds.
             */
            constructor(
                ValidatorPool _validatorPool,
                address _colosseum,
                uint256 _submissionInterval,
                uint256 _l2BlockTime,
                uint256 _startingBlockNumber,
                uint256 _startingTimestamp,
                uint256 _finalizationPeriodSeconds
            ) Semver(1, 0, 0) {
                require(_l2BlockTime > 0, "L2OutputOracle: L2 block time must be greater than 0");
                require(
                    _submissionInterval > 0,
                    "L2OutputOracle: submission interval must be greater than 0"
                );
                VALIDATOR_POOL = _validatorPool;
                COLOSSEUM = _colosseum;
                SUBMISSION_INTERVAL = _submissionInterval;
                L2_BLOCK_TIME = _l2BlockTime;
                FINALIZATION_PERIOD_SECONDS = _finalizationPeriodSeconds;
                initialize(_startingBlockNumber, _startingTimestamp);
            }
            /**
             * @notice Initializer.
             *
             * @param _startingBlockNumber Block number for the first recorded L2 block.
             * @param _startingTimestamp   Timestamp for the first recorded L2 block.
             */
            function initialize(uint256 _startingBlockNumber, uint256 _startingTimestamp)
                public
                initializer
            {
                require(
                    _startingTimestamp <= block.timestamp,
                    "L2OutputOracle: starting L2 timestamp must be less than current time"
                );
                startingTimestamp = _startingTimestamp;
                startingBlockNumber = _startingBlockNumber;
            }
            /**
             * @notice Replaces the output that corresponds to the given output index.
             *         Only the Colosseum contract can replace an output.
             *
             * @param _l2OutputIndex Index of the L2 output to be replaced.
             * @param _newOutputRoot The L2 output root to replace the existing one.
             * @param _submitter     Address of the L2 output submitter.
             */
            function replaceL2Output(
                uint256 _l2OutputIndex,
                bytes32 _newOutputRoot,
                address _submitter
            ) external {
                require(
                    msg.sender == COLOSSEUM,
                    "L2OutputOracle: only the colosseum contract can replace an output"
                );
                require(_submitter != address(0), "L2OutputOracle: submitter address cannot be zero");
                // Make sure we're not *increasing* the length of the array.
                require(
                    _l2OutputIndex < l2Outputs.length,
                    "L2OutputOracle: cannot replace an output after the latest output index"
                );
                Types.CheckpointOutput storage output = l2Outputs[_l2OutputIndex];
                // Do not allow replacing any outputs that have already been finalized.
                require(
                    block.timestamp - output.timestamp < FINALIZATION_PERIOD_SECONDS,
                    "L2OutputOracle: cannot replace an output that has already been finalized"
                );
                output.outputRoot = _newOutputRoot;
                output.submitter = _submitter;
                emit OutputReplaced(_l2OutputIndex, _newOutputRoot);
            }
            /**
             * @notice Accepts an outputRoot and the block number of the corresponding L2 block.
             *         The block number must be equal to the current value returned by `nextBlockNumber()`
             *         in order to be accepted. This function may only be called by the validator.
             *
             * @param _outputRoot    The L2 output of the checkpoint block.
             * @param _l2BlockNumber The L2 block number that resulted in _outputRoot.
             * @param _l1BlockHash   A block hash which must be included in the current chain.
             * @param _l1BlockNumber The block number with the specified block hash.
             */
            function submitL2Output(
                bytes32 _outputRoot,
                uint256 _l2BlockNumber,
                bytes32 _l1BlockHash,
                uint256 _l1BlockNumber
            ) external payable {
                address nextValidator = VALIDATOR_POOL.nextValidator();
                // If it's not a public round, only selected validators can submit output.
                if (nextValidator != Constants.VALIDATOR_PUBLIC_ROUND_ADDRESS) {
                    require(
                        msg.sender == nextValidator,
                        "L2OutputOracle: only the next selected validator can submit output"
                    );
                }
                require(
                    _l2BlockNumber == nextBlockNumber(),
                    "L2OutputOracle: block number must be equal to next expected block number"
                );
                require(
                    computeL2Timestamp(_l2BlockNumber) < block.timestamp,
                    "L2OutputOracle: cannot submit L2 output in the future"
                );
                require(
                    _outputRoot != bytes32(0),
                    "L2OutputOracle: L2 checkpoint output cannot be the zero hash"
                );
                if (_l1BlockHash != bytes32(0) && blockhash(_l1BlockNumber) != bytes32(0)) {
                    // This check allows the validator to submit an output based on a given L1 block,
                    // without fear that it will be reorged out.
                    // It will be skipped if the blockheight provided is more than 256 blocks behind the
                    // chain tip (as the hash will return as zero).
                    require(
                        blockhash(_l1BlockNumber) == _l1BlockHash,
                        "L2OutputOracle: block hash does not match the hash at the expected height"
                    );
                }
                uint256 outputIndex = nextOutputIndex();
                l2Outputs.push(
                    Types.CheckpointOutput({
                        submitter: msg.sender,
                        outputRoot: _outputRoot,
                        timestamp: uint128(block.timestamp),
                        l2BlockNumber: uint128(_l2BlockNumber)
                    })
                );
                emit OutputSubmitted(_outputRoot, outputIndex, _l2BlockNumber, block.timestamp);
                VALIDATOR_POOL.createBond(
                    outputIndex,
                    uint128(block.timestamp + FINALIZATION_PERIOD_SECONDS)
                );
            }
            /**
             * @notice Returns an output by index. Reverts if output is not found at the given index.
             *
             * @param _l2OutputIndex Index of the output to return.
             *
             * @return The output at the given index.
             */
            function getL2Output(uint256 _l2OutputIndex)
                external
                view
                returns (Types.CheckpointOutput memory)
            {
                return l2Outputs[_l2OutputIndex];
            }
            /**
             * @notice Returns the index of the L2 output that checkpoints a given L2 block number. Uses a
             *         binary search to find the first output greater than or equal to the given block.
             *
             * @param _l2BlockNumber L2 block number to find a checkpoint for.
             *
             * @return Index of the first checkpoint that commits to the given L2 block number.
             */
            function getL2OutputIndexAfter(uint256 _l2BlockNumber) public view returns (uint256) {
                // Make sure an output for this block number has actually been submitted.
                require(
                    _l2BlockNumber <= latestBlockNumber(),
                    "L2OutputOracle: cannot get output for a block that has not been submitted"
                );
                // Make sure there's at least one output submitted.
                require(
                    l2Outputs.length > 0,
                    "L2OutputOracle: cannot get output as no outputs have been submitted yet"
                );
                // Find the output via binary search, guaranteed to exist.
                uint256 lo = 0;
                uint256 hi = l2Outputs.length;
                while (lo < hi) {
                    uint256 mid = (lo + hi) / 2;
                    if (l2Outputs[mid].l2BlockNumber < _l2BlockNumber) {
                        lo = mid + 1;
                    } else {
                        hi = mid;
                    }
                }
                return lo;
            }
            /**
             * @notice Returns the L2 checkpoint output that checkpoints a given L2 block number.
             *
             * @param _l2BlockNumber L2 block number to find a checkpoint for.
             *
             * @return First checkpoint that commits to the given L2 block number.
             */
            function getL2OutputAfter(uint256 _l2BlockNumber)
                external
                view
                returns (Types.CheckpointOutput memory)
            {
                return l2Outputs[getL2OutputIndexAfter(_l2BlockNumber)];
            }
            /**
             * @notice Returns the index of the latest submitted output. Will revert if no outputs
             *         have been submitted yet.
             *
             * @return The index of the latest submitted output.
             */
            function latestOutputIndex() external view returns (uint256) {
                return l2Outputs.length - 1;
            }
            /**
             * @notice Returns the index of the next output to be submitted.
             *
             * @return The index of the next output to be submitted.
             */
            function nextOutputIndex() public view returns (uint256) {
                return l2Outputs.length;
            }
            /**
             * @notice Returns the block number of the latest submitted L2 checkpoint output. If no outputs
             *         have been submitted yet then this function will return the starting block number.
             *
             * @return Latest submitted L2 block number.
             */
            function latestBlockNumber() public view returns (uint256) {
                return
                    l2Outputs.length == 0
                        ? startingBlockNumber
                        : l2Outputs[l2Outputs.length - 1].l2BlockNumber;
            }
            /**
             * @notice Computes the block number of the next L2 block that needs to be checkpointed. If no
             *         outputs have been submitted yet then this function will return the latest block
             *         number, which is the starting block number.
             *
             * @return Next L2 block number.
             */
            function nextBlockNumber() public view returns (uint256) {
                return
                    l2Outputs.length == 0 ? latestBlockNumber() : latestBlockNumber() + SUBMISSION_INTERVAL;
            }
            /**
             * @notice Returns the L2 timestamp corresponding to a given L2 block number.
             *
             * @param _l2BlockNumber The L2 block number of the target block.
             *
             * @return L2 timestamp of the given block.
             */
            function computeL2Timestamp(uint256 _l2BlockNumber) public view returns (uint256) {
                return startingTimestamp + ((_l2BlockNumber - startingBlockNumber) * L2_BLOCK_TIME);
            }
            /**
             * @notice Returns the address of the L2 output submitter.
             *
             * @param _outputIndex Index of an output.
             *
             * @return Address of the submitter.
             */
            function getSubmitter(uint256 _outputIndex) external view returns (address) {
                return l2Outputs[_outputIndex].submitter;
            }
            /**
             * @notice Returns if the output of given index is finalized.
             *
             * @param _outputIndex Index of an output.
             *
             * @return If the given output is finalized or not.
             */
            function isFinalized(uint256 _outputIndex) external view returns (bool) {
                return l2Outputs[_outputIndex].timestamp + FINALIZATION_PERIOD_SECONDS < block.timestamp;
            }
            /**
             * @notice Returns the finalization time of given output index.
             *
             * @param _outputIndex Index of an output.
             *
             * @return The finalization time of given output index.
             */
            function finalizedAt(uint256 _outputIndex) external view returns (uint256) {
                return l2Outputs[_outputIndex].timestamp + FINALIZATION_PERIOD_SECONDS;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Initializable } from "@openzeppelin/contracts/proxy/utils/Initializable.sol";
        import { Math } from "@openzeppelin/contracts/utils/math/Math.sol";
        import { Arithmetic } from "../libraries/Arithmetic.sol";
        import { Burn } from "../libraries/Burn.sol";
        /**
         * @custom:upgradeable
         * @title ResourceMetering
         * @notice ResourceMetering implements an EIP-1559 style resource metering system where pricing
         *         updates automatically based on current demand.
         */
        abstract contract ResourceMetering is Initializable {
            /**
             * @notice Represents the various parameters that control the way in which resources are
             *         metered. Corresponds to the EIP-1559 resource metering system.
             *
             * @custom:field prevBaseFee   Base fee from the previous block(s).
             * @custom:field prevBoughtGas Amount of gas bought so far in the current block.
             * @custom:field prevBlockNum  Last block number that the base fee was updated.
             */
            struct ResourceParams {
                uint128 prevBaseFee;
                uint64 prevBoughtGas;
                uint64 prevBlockNum;
            }
            /**
             * @notice Represents the configuration for the EIP-1559 based curve for the deposit gas
             *         market. These values should be set with care as it is possible to set them in
             *         a way that breaks the deposit gas market. The target resource limit is defined as
             *         maxResourceLimit / elasticityMultiplier. This struct was designed to fit within a
             *         single word. There is additional space for additions in the future.
             *
             * @custom:field maxResourceLimit             Represents the maximum amount of deposit gas that
             *                                            can be purchased per block.
             * @custom:field elasticityMultiplier         Determines the target resource limit along with
             *                                            the resource limit.
             * @custom:field baseFeeMaxChangeDenominator  Determines max change on fee per block.
             * @custom:field minimumBaseFee               The min deposit base fee, it is clamped to this
             *                                            value.
             * @custom:field systemTxMaxGas               The amount of gas supplied to the system
             *                                            transaction. This should be set to the same number
             *                                            that the kroma-node sets as the gas limit for the
             *                                            system transaction.
             * @custom:field maximumBaseFee               The max deposit base fee, it is clamped to this
             *                                            value.
             */
            struct ResourceConfig {
                uint32 maxResourceLimit;
                uint8 elasticityMultiplier;
                uint8 baseFeeMaxChangeDenominator;
                uint32 minimumBaseFee;
                uint32 systemTxMaxGas;
                uint128 maximumBaseFee;
            }
            /**
             * @notice EIP-1559 style gas parameters.
             */
            ResourceParams public params;
            /**
             * @notice Reserve extra slots (to a total of 50) in the storage layout for future upgrades.
             */
            uint256[48] private __gap;
            /**
             * @notice Meters access to a function based an amount of a requested resource.
             *
             * @param _amount Amount of the resource requested.
             */
            modifier metered(uint64 _amount) {
                // Record initial gas amount so we can refund for it later.
                uint256 initialGas = gasleft();
                // Run the underlying function.
                _;
                // Run the metering function.
                _metered(_amount, initialGas);
            }
            /**
             * @notice An internal function that holds all of the logic for metering a resource.
             *
             * @param _amount     Amount of the resource requested.
             * @param _initialGas The amount of gas before any modifier execution.
             */
            function _metered(uint64 _amount, uint256 _initialGas) internal {
                // Update block number and base fee if necessary.
                uint256 blockDiff = block.number - params.prevBlockNum;
                ResourceConfig memory config = _resourceConfig();
                int256 targetResourceLimit = int256(uint256(config.maxResourceLimit)) /
                    int256(uint256(config.elasticityMultiplier));
                if (blockDiff > 0) {
                    // Handle updating EIP-1559 style gas parameters. We use EIP-1559 to restrict the rate
                    // at which deposits can be created and therefore limit the potential for deposits to
                    // spam the L2 system. Fee scheme is very similar to EIP-1559 with minor changes.
                    int256 gasUsedDelta = int256(uint256(params.prevBoughtGas)) - targetResourceLimit;
                    int256 baseFeeDelta = (int256(uint256(params.prevBaseFee)) * gasUsedDelta) /
                        (targetResourceLimit * int256(uint256(config.baseFeeMaxChangeDenominator)));
                    // Update base fee by adding the base fee delta and clamp the resulting value between
                    // min and max.
                    int256 newBaseFee = Arithmetic.clamp({
                        _value: int256(uint256(params.prevBaseFee)) + baseFeeDelta,
                        _min: int256(uint256(config.minimumBaseFee)),
                        _max: int256(uint256(config.maximumBaseFee))
                    });
                    // If we skipped more than one block, we also need to account for every empty block.
                    // Empty block means there was no demand for deposits in that block, so we should
                    // reflect this lack of demand in the fee.
                    if (blockDiff > 1) {
                        // Update the base fee by repeatedly applying the exponent 1-(1/change_denominator)
                        // blockDiff - 1 times. Simulates multiple empty blocks. Clamp the resulting value
                        // between min and max.
                        newBaseFee = Arithmetic.clamp({
                            _value: Arithmetic.cdexp({
                                _coefficient: newBaseFee,
                                _denominator: int256(uint256(config.baseFeeMaxChangeDenominator)),
                                _exponent: int256(blockDiff - 1)
                            }),
                            _min: int256(uint256(config.minimumBaseFee)),
                            _max: int256(uint256(config.maximumBaseFee))
                        });
                    }
                    // Update new base fee, reset bought gas, and update block number.
                    params.prevBaseFee = uint128(uint256(newBaseFee));
                    params.prevBoughtGas = 0;
                    params.prevBlockNum = uint64(block.number);
                }
                // Make sure we can actually buy the resource amount requested by the user.
                params.prevBoughtGas += _amount;
                require(
                    int256(uint256(params.prevBoughtGas)) <= int256(uint256(config.maxResourceLimit)),
                    "ResourceMetering: cannot buy more gas than available gas limit"
                );
                // Determine the amount of ETH to be paid.
                uint256 resourceCost = uint256(_amount) * uint256(params.prevBaseFee);
                // We currently charge for this ETH amount as an L1 gas burn, so we convert the ETH amount
                // into gas by dividing by the L1 base fee. We assume a minimum base fee of 1 gwei to avoid
                // division by zero for L1s that don't support 1559 or to avoid excessive gas burns during
                // periods of extremely low L1 demand. One-day average gas fee hasn't dipped below 1 gwei
                // during any 1 day period in the last 5 years, so should be fine.
                uint256 gasCost = resourceCost / Math.max(block.basefee, 1 gwei);
                // Give the user a refund based on the amount of gas they used to do all of the work up to
                // this point. Since we're at the end of the modifier, this should be pretty accurate. Acts
                // effectively like a dynamic stipend (with a minimum value).
                uint256 usedGas = _initialGas - gasleft();
                if (gasCost > usedGas) {
                    Burn.gas(gasCost - usedGas);
                }
            }
            /**
             * @notice Virtual function that returns the resource config. Contracts that inherit this
             *         contract must implement this function.
             *
             * @return ResourceConfig
             */
            function _resourceConfig() internal virtual returns (ResourceConfig memory);
            /**
             * @notice Sets initial resource parameter values. This function must either be called by the
             *         initializer function of an upgradeable child contract.
             */
            // solhint-disable-next-line func-name-mixedcase
            function __ResourceMetering_init() internal onlyInitializing {
                params = ResourceParams({
                    prevBaseFee: 1 gwei,
                    prevBoughtGas: 0,
                    prevBlockNum: uint64(block.number)
                });
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import {
            OwnableUpgradeable
        } from "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
        import { Constants } from "../libraries/Constants.sol";
        import { Semver } from "../universal/Semver.sol";
        import { ResourceMetering } from "./ResourceMetering.sol";
        /**
         * @title SystemConfig
         * @notice The SystemConfig contract is used to manage configuration of a Kroma network. All
         *         configuration is stored on L1 and picked up by L2 as part of the derivation of the L2
         *         chain.
         */
        contract SystemConfig is OwnableUpgradeable, Semver {
            /**
             * @notice Enum representing different types of updates.
             *
             * @custom:value BATCHER                 Represents an update to the batcher hash.
             * @custom:value GAS_CONFIG              Represents an update to txn fee config on L2.
             * @custom:value GAS_LIMIT               Represents an update to gas limit on L2.
             * @custom:value UNSAFE_BLOCK_SIGNER     Represents an update to the signer key for unsafe
             *                                       block distribution.
             * @custom:value VALIDATOR_REWARD_SCALAR Represents an update to validator reward scalar.
             */
            enum UpdateType {
                BATCHER,
                GAS_CONFIG,
                GAS_LIMIT,
                UNSAFE_BLOCK_SIGNER,
                VALIDATOR_REWARD_SCALAR
            }
            /**
             * @notice Version identifier, used for upgrades.
             */
            uint256 public constant VERSION = 0;
            /**
             * @notice Storage slot that the unsafe block signer is stored at. Storing it at this
             *         deterministic storage slot allows for decoupling the storage layout from the way
             *         that `solc` lays out storage. The `kroma-node` uses a storage proof to fetch this value.
             */
            bytes32 public constant UNSAFE_BLOCK_SIGNER_SLOT = keccak256("systemconfig.unsafeblocksigner");
            /**
             * @notice Fixed L2 gas overhead. Used as part of the L2 fee calculation.
             */
            uint256 public overhead;
            /**
             * @notice Dynamic L2 gas overhead. Used as part of the L2 fee calculation.
             */
            uint256 public scalar;
            /**
             * @notice Identifier for the batcher. For version 1 of this configuration, this is represented
             *         as an address left-padded with zeros to 32 bytes.
             */
            bytes32 public batcherHash;
            /**
             * @notice L2 block gas limit.
             */
            uint64 public gasLimit;
            /**
             * @notice The configuration for the deposit fee market. Used by the KromaPortal
             *         to meter the cost of buying L2 gas on L1. Set as internal and wrapped with a getter
             *         so that the struct is returned instead of a tuple.
             */
            ResourceMetering.ResourceConfig internal _resourceConfig;
            /**
             * @notice The scalar value to distribute transaction fees as validator reward.
             *         The denominator is 10000, so the ratio is expressed in 4 decimal places.
             */
            uint256 public validatorRewardScalar;
            /**
             * @notice Emitted when configuration is updated
             *
             * @param version    SystemConfig version.
             * @param updateType Type of update.
             * @param data       Encoded update data.
             */
            event ConfigUpdate(uint256 indexed version, UpdateType indexed updateType, bytes data);
            /**
             * @custom:semver 1.0.0
             *
             * @param _owner                 Initial owner of the contract.
             * @param _overhead              Initial overhead value.
             * @param _scalar                Initial scalar value.
             * @param _batcherHash           Initial batcher hash.
             * @param _gasLimit              Initial gas limit.
             * @param _unsafeBlockSigner     Initial unsafe block signer address.
             * @param _config                Initial resource config.
             * @param _validatorRewardScalar Initial validator reward scalar.
             */
            constructor(
                address _owner,
                uint256 _overhead,
                uint256 _scalar,
                bytes32 _batcherHash,
                uint64 _gasLimit,
                address _unsafeBlockSigner,
                ResourceMetering.ResourceConfig memory _config,
                uint256 _validatorRewardScalar
            ) Semver(1, 0, 0) {
                initialize(
                    _owner,
                    _overhead,
                    _scalar,
                    _batcherHash,
                    _gasLimit,
                    _unsafeBlockSigner,
                    _config,
                    _validatorRewardScalar
                );
            }
            /**
             * @notice Initializer. The resource config must be set before the
             *         require check.
             *
             * @param _owner                 Initial owner of the contract.
             * @param _overhead              Initial overhead value.
             * @param _scalar                Initial scalar value.
             * @param _batcherHash           Initial batcher hash.
             * @param _gasLimit              Initial gas limit.
             * @param _unsafeBlockSigner     Initial unsafe block signer address.
             * @param _config                Initial ResourceConfig.
             * @param _validatorRewardScalar Initial validator reward scalar.
             */
            function initialize(
                address _owner,
                uint256 _overhead,
                uint256 _scalar,
                bytes32 _batcherHash,
                uint64 _gasLimit,
                address _unsafeBlockSigner,
                ResourceMetering.ResourceConfig memory _config,
                uint256 _validatorRewardScalar
            ) public initializer {
                __Ownable_init();
                transferOwnership(_owner);
                overhead = _overhead;
                scalar = _scalar;
                batcherHash = _batcherHash;
                gasLimit = _gasLimit;
                _setUnsafeBlockSigner(_unsafeBlockSigner);
                _setResourceConfig(_config);
                require(_gasLimit >= minimumGasLimit(), "SystemConfig: gas limit too low");
                validatorRewardScalar = _validatorRewardScalar;
            }
            /**
             * @notice Returns the minimum L2 gas limit that can be safely set for the system to
             *         operate. The L2 gas limit must be larger than or equal to the amount of
             *         gas that is allocated for deposits per block plus the amount of gas that
             *         is allocated for the system transaction.
             *         This function is used to determine if changes to parameters are safe.
             *
             * @return uint64
             */
            function minimumGasLimit() public view returns (uint64) {
                return uint64(_resourceConfig.maxResourceLimit) + uint64(_resourceConfig.systemTxMaxGas);
            }
            /**
             * @notice High level getter for the unsafe block signer address. Unsafe blocks can be
             *         propagated across the p2p network if they are signed by the key corresponding to
             *         this address.
             *
             * @return Address of the unsafe block signer.
             */
            // solhint-disable-next-line ordering
            function unsafeBlockSigner() external view returns (address) {
                address addr;
                bytes32 slot = UNSAFE_BLOCK_SIGNER_SLOT;
                assembly {
                    addr := sload(slot)
                }
                return addr;
            }
            /**
             * @notice Updates the unsafe block signer address.
             *
             * @param _unsafeBlockSigner New unsafe block signer address.
             */
            function setUnsafeBlockSigner(address _unsafeBlockSigner) external onlyOwner {
                _setUnsafeBlockSigner(_unsafeBlockSigner);
                bytes memory data = abi.encode(_unsafeBlockSigner);
                emit ConfigUpdate(VERSION, UpdateType.UNSAFE_BLOCK_SIGNER, data);
            }
            /**
             * @notice Updates the batcher hash.
             *
             * @param _batcherHash New batcher hash.
             */
            function setBatcherHash(bytes32 _batcherHash) external onlyOwner {
                batcherHash = _batcherHash;
                bytes memory data = abi.encode(_batcherHash);
                emit ConfigUpdate(VERSION, UpdateType.BATCHER, data);
            }
            /**
             * @notice Updates gas config.
             *
             * @param _overhead New overhead value.
             * @param _scalar   New scalar value.
             */
            function setGasConfig(uint256 _overhead, uint256 _scalar) external onlyOwner {
                overhead = _overhead;
                scalar = _scalar;
                bytes memory data = abi.encode(_overhead, _scalar);
                emit ConfigUpdate(VERSION, UpdateType.GAS_CONFIG, data);
            }
            /**
             * @notice Updates the L2 gas limit.
             *
             * @param _gasLimit New gas limit.
             */
            function setGasLimit(uint64 _gasLimit) external onlyOwner {
                require(_gasLimit >= minimumGasLimit(), "SystemConfig: gas limit too low");
                gasLimit = _gasLimit;
                bytes memory data = abi.encode(_gasLimit);
                emit ConfigUpdate(VERSION, UpdateType.GAS_LIMIT, data);
            }
            /**
             * @notice Low level setter for the unsafe block signer address. This function exists to
             *         deduplicate code around storing the unsafeBlockSigner address in storage.
             *
             * @param _unsafeBlockSigner New unsafeBlockSigner value.
             */
            function _setUnsafeBlockSigner(address _unsafeBlockSigner) internal {
                bytes32 slot = UNSAFE_BLOCK_SIGNER_SLOT;
                assembly {
                    sstore(slot, _unsafeBlockSigner)
                }
            }
            /**
             * @notice A getter for the resource config. Ensures that the struct is
             *         returned instead of a tuple.
             *
             * @return ResourceConfig
             */
            function resourceConfig() external view returns (ResourceMetering.ResourceConfig memory) {
                return _resourceConfig;
            }
            /**
             * @notice An external setter for the resource config. In the future, this
             *         method may emit an event that the `kroma-node` picks up for when the
             *         resource config is changed.
             *
             * @param _config The new resource config values.
             */
            function setResourceConfig(ResourceMetering.ResourceConfig memory _config) external onlyOwner {
                _setResourceConfig(_config);
            }
            /**
             * @notice An internal setter for the resource config. Ensures that the
             *         config is sane before storing it by checking for invariants.
             *
             * @param _config The new resource config.
             */
            function _setResourceConfig(ResourceMetering.ResourceConfig memory _config) internal {
                // Min base fee must be less than or equal to max base fee.
                require(
                    _config.minimumBaseFee <= _config.maximumBaseFee,
                    "SystemConfig: min base fee must be less than max base"
                );
                // Base fee change denominator must be greater than 1.
                require(
                    _config.baseFeeMaxChangeDenominator > 1,
                    "SystemConfig: denominator must be larger than 1"
                );
                // Max resource limit plus system tx gas must be less than or equal to the L2 gas limit.
                // The gas limit must be increased before these values can be increased.
                require(
                    _config.maxResourceLimit + _config.systemTxMaxGas <= gasLimit,
                    "SystemConfig: gas limit too low"
                );
                // Elasticity multiplier must be greater than 0.
                require(
                    _config.elasticityMultiplier > 0,
                    "SystemConfig: elasticity multiplier cannot be 0"
                );
                // No precision loss when computing target resource limit.
                require(
                    ((_config.maxResourceLimit / _config.elasticityMultiplier) *
                        _config.elasticityMultiplier) == _config.maxResourceLimit,
                    "SystemConfig: precision loss with target resource limit"
                );
                _resourceConfig = _config;
            }
            /**
             * @notice Updates the validator reward scalar.
             *
             * @param _validatorRewardScalar New validator reward scalar.
             */
            function setValidatorRewardScalar(uint256 _validatorRewardScalar) external onlyOwner {
                require(
                    _validatorRewardScalar <= Constants.VALIDATOR_REWARD_DENOMINATOR,
                    "SystemConfig: the max value of validator reward scalar has been exceeded"
                );
                validatorRewardScalar = _validatorRewardScalar;
                bytes memory data = abi.encode(_validatorRewardScalar);
                emit ConfigUpdate(VERSION, UpdateType.VALIDATOR_REWARD_SCALAR, data);
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Bytes } from "../libraries/Bytes.sol";
        import { NodeReader } from "../libraries/NodeReader.sol";
        import { IZKMerkleTrie } from "./IZKMerkleTrie.sol";
        import { ZKTrieHasher } from "./ZKTrieHasher.sol";
        /**
         * @custom:proxied
         * @title ZKMerkleTrie
         * @notice The ZKMerkleTrie is contract which can produce a hash according to ZKTrie.
         *         This owns an interface of Poseidon2 that is required to compute hash used by ZKTrie.
         */
        contract ZKMerkleTrie is IZKMerkleTrie, ZKTrieHasher {
            /**
             * @notice Struct representing a node in the trie.
             */
            struct TrieNode {
                bytes encoded;
                NodeReader.Node decoded;
            }
            /**
             * @notice Magic hash which indicates
             *         See https://github.com/kroma-network/zktrie/blob/main/trie/zk_trie_proof.go.
             */
            bytes32 private constant MAGIC_SMT_BYTES_HASH =
                keccak256(
                    hex"5448495320495320534f4d45204d4147494320425954455320464f5220534d54206d3172525867503278704449"
                );
            /**
             * @param _poseidon2 The address of poseidon2 contract.
             */
            constructor(address _poseidon2) ZKTrieHasher(_poseidon2) {}
            /**
             * @notice Checks if a given bytes is MAGIC_SMT_BYTES_HASH.
             *
             * @param _value Bytes to be compared.
             */
            function isMagicSmtBytesHash(bytes memory _value) private pure returns (bool) {
                return keccak256(_value) == MAGIC_SMT_BYTES_HASH;
            }
            /**
             * @inheritdoc IZKMerkleTrie
             */
            function verifyInclusionProof(
                bytes32 _key,
                bytes memory _value,
                bytes[] memory _proofs,
                bytes32 _root
            ) external view returns (bool) {
                (bool exists, bytes memory value) = this.get(_key, _proofs, _root);
                return (exists && Bytes.equal(_value, value));
            }
            /**
             * @notice Retrieves the value associated with a given key.
             *
             * @param _key    Key to search for, as hex bytes.
             * @param _proofs Merkle trie inclusion proof for the key.
             * @param _root   Known root of the Merkle trie.
             *
             * @return Whether or not the key exists.
             * @return Value of the key if it exists.
             */
            function get(
                bytes32 _key,
                bytes[] memory _proofs,
                bytes32 _root
            ) external view returns (bool, bytes memory) {
                require(_proofs.length >= 2, "ZKMerkleTrie: provided proof is too short");
                require(
                    isMagicSmtBytesHash(_proofs[_proofs.length - 1]),
                    "ZKMerkleTrie: the last item is not magic hash"
                );
                bytes32 key = _hashElem(_key);
                TrieNode[] memory nodes = _parseProofs(_proofs);
                NodeReader.Node memory currentNode;
                bytes32 computedKey = bytes32(0);
                bool exists = false;
                bool empty = false;
                bytes memory value = bytes("");
                for (uint256 i = nodes.length - 2; i >= 0; ) {
                    currentNode = nodes[i].decoded;
                    if (currentNode.nodeType == NodeReader.NodeType.MIDDLE) {
                        bool isLeft = _isLeft(key, i);
                        if (isLeft) {
                            require(computedKey == currentNode.childL, "ZKMerkleTrie: invalid key L");
                        } else {
                            require(computedKey == currentNode.childR, "ZKMerkleTrie: invalid key R");
                        }
                        computedKey = _hashFixed2Elems(
                            currentNode.childL,
                            currentNode.childR
                        );
                    } else if (currentNode.nodeType == NodeReader.NodeType.LEAF) {
                        require(!exists && !empty, "ZKMerkleTrie: duplicated terminal node");
                        exists = currentNode.nodeKey == key;
                        if (!exists) {
                            break;
                        }
                        computedKey = _hashFixed3Elems(
                            bytes32(uint256(1)),
                            currentNode.nodeKey,
                            _valueHash(currentNode.compressedFlags, currentNode.valuePreimage)
                        );
                        bytes32[] memory valuePreimage = currentNode.valuePreimage;
                        uint256 len = valuePreimage.length;
                        assembly {
                            value := valuePreimage
                            mstore(value, mul(len, 32))
                        }
                        if (currentNode.keyPreimage != bytes32(0)) {
                            // NOTE(chokobole): The comparison order is important, because in this setting,
                            // first condition is mostly evaluted to be true. When we're sure about
                            // database preimage, then we need to enable just one of check below!
                            require(
                                currentNode.keyPreimage == _key || currentNode.keyPreimage == key,
                                "ZKMerkleTrie: invalid key preimage"
                            );
                        }
                    } else if (currentNode.nodeType == NodeReader.NodeType.EMPTY) {
                        require(!exists && !empty, "ZKMerkleTrie: duplicated terminal node");
                        empty = true;
                    }
                    if (i == 0) {
                        require(computedKey == _root, "ZKMerkeTrie: invalid root");
                        break;
                    }
                    unchecked {
                        --i;
                    }
                }
                return (exists, value);
            }
            /**
             * @notice Parses an array of proof elements into a new array that contains both the original
             *         encoded element and the decoded element.
             *
             * @param _proofs Array of proof elements to parse.
             *
             * @return TrieNode parsed into easily accessible structs.
             */
            function _parseProofs(bytes[] memory _proofs) private pure returns (TrieNode[] memory) {
                uint256 length = _proofs.length;
                TrieNode[] memory nodes = new TrieNode[](length);
                // NOTE(chokobole): Last proof is MAGIC_SMT_BYTES_HASH!
                for (uint256 i = 0; i < length - 1; ) {
                    NodeReader.Node memory node = NodeReader.readNode(_proofs[i]);
                    nodes[i] = TrieNode({ encoded: _proofs[i], decoded: node });
                    unchecked {
                        ++i;
                    }
                }
                return nodes;
            }
            /**
             * @notice Computes merkle path at index n based on a given keyPreimage.
             *
             * @param _keyPreimage Keypreimage.
             * @param _n           Bit to mask.
             *
             * @return Whether merkle path is left or not.
             */
            function _isLeft(bytes32 _keyPreimage, uint256 _n) private pure returns (bool) {
                require(_n < 256, "ZKMerkleTrie: too long depth");
                return _keyPreimage & bytes32(1 << _n) == 0;
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
        pragma solidity ^0.8.1;
        /**
         * @dev Collection of functions related to the address type
         */
        library Address {
            /**
             * @dev Returns true if `account` is a contract.
             *
             * [IMPORTANT]
             * ====
             * It is unsafe to assume that an address for which this function returns
             * false is an externally-owned account (EOA) and not a contract.
             *
             * Among others, `isContract` will return false for the following
             * types of addresses:
             *
             *  - an externally-owned account
             *  - a contract in construction
             *  - an address where a contract will be created
             *  - an address where a contract lived, but was destroyed
             *
             * Furthermore, `isContract` will also return true if the target contract within
             * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
             * which only has an effect at the end of a transaction.
             * ====
             *
             * [IMPORTANT]
             * ====
             * You shouldn't rely on `isContract` to protect against flash loan attacks!
             *
             * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
             * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
             * constructor.
             * ====
             */
            function isContract(address account) internal view returns (bool) {
                // This method relies on extcodesize/address.code.length, which returns 0
                // for contracts in construction, since the code is only stored at the end
                // of the constructor execution.
                return account.code.length > 0;
            }
            /**
             * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
             * `recipient`, forwarding all available gas and reverting on errors.
             *
             * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
             * of certain opcodes, possibly making contracts go over the 2300 gas limit
             * imposed by `transfer`, making them unable to receive funds via
             * `transfer`. {sendValue} removes this limitation.
             *
             * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
             *
             * IMPORTANT: because control is transferred to `recipient`, care must be
             * taken to not create reentrancy vulnerabilities. Consider using
             * {ReentrancyGuard} or the
             * https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
             */
            function sendValue(address payable recipient, uint256 amount) internal {
                require(address(this).balance >= amount, "Address: insufficient balance");
                (bool success, ) = recipient.call{value: amount}("");
                require(success, "Address: unable to send value, recipient may have reverted");
            }
            /**
             * @dev Performs a Solidity function call using a low level `call`. A
             * plain `call` is an unsafe replacement for a function call: use this
             * function instead.
             *
             * If `target` reverts with a revert reason, it is bubbled up by this
             * function (like regular Solidity function calls).
             *
             * Returns the raw returned data. To convert to the expected return value,
             * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
             *
             * Requirements:
             *
             * - `target` must be a contract.
             * - calling `target` with `data` must not revert.
             *
             * _Available since v3.1._
             */
            function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                return functionCallWithValue(target, data, 0, "Address: low-level call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
             * `errorMessage` as a fallback revert reason when `target` reverts.
             *
             * _Available since v3.1._
             */
            function functionCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal returns (bytes memory) {
                return functionCallWithValue(target, data, 0, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but also transferring `value` wei to `target`.
             *
             * Requirements:
             *
             * - the calling contract must have an ETH balance of at least `value`.
             * - the called Solidity function must be `payable`.
             *
             * _Available since v3.1._
             */
            function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
            }
            /**
             * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
             * with `errorMessage` as a fallback revert reason when `target` reverts.
             *
             * _Available since v3.1._
             */
            function functionCallWithValue(
                address target,
                bytes memory data,
                uint256 value,
                string memory errorMessage
            ) internal returns (bytes memory) {
                require(address(this).balance >= value, "Address: insufficient balance for call");
                (bool success, bytes memory returndata) = target.call{value: value}(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but performing a static call.
             *
             * _Available since v3.3._
             */
            function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                return functionStaticCall(target, data, "Address: low-level static call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
             * but performing a static call.
             *
             * _Available since v3.3._
             */
            function functionStaticCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal view returns (bytes memory) {
                (bool success, bytes memory returndata) = target.staticcall(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but performing a delegate call.
             *
             * _Available since v3.4._
             */
            function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                return functionDelegateCall(target, data, "Address: low-level delegate call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
             * but performing a delegate call.
             *
             * _Available since v3.4._
             */
            function functionDelegateCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal returns (bytes memory) {
                (bool success, bytes memory returndata) = target.delegatecall(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
             * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
             *
             * _Available since v4.8._
             */
            function verifyCallResultFromTarget(
                address target,
                bool success,
                bytes memory returndata,
                string memory errorMessage
            ) internal view returns (bytes memory) {
                if (success) {
                    if (returndata.length == 0) {
                        // only check isContract if the call was successful and the return data is empty
                        // otherwise we already know that it was a contract
                        require(isContract(target), "Address: call to non-contract");
                    }
                    return returndata;
                } else {
                    _revert(returndata, errorMessage);
                }
            }
            /**
             * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
             * revert reason or using the provided one.
             *
             * _Available since v4.3._
             */
            function verifyCallResult(
                bool success,
                bytes memory returndata,
                string memory errorMessage
            ) internal pure returns (bytes memory) {
                if (success) {
                    return returndata;
                } else {
                    _revert(returndata, errorMessage);
                }
            }
            function _revert(bytes memory returndata, string memory errorMessage) private pure {
                // Look for revert reason and bubble it up if present
                if (returndata.length > 0) {
                    // The easiest way to bubble the revert reason is using memory via assembly
                    /// @solidity memory-safe-assembly
                    assembly {
                        let returndata_size := mload(returndata)
                        revert(add(32, returndata), returndata_size)
                    }
                } else {
                    revert(errorMessage);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        import { Hashing } from "./Hashing.sol";
        import { Types } from "./Types.sol";
        import { RLPWriter } from "./rlp/RLPWriter.sol";
        /**
         * @title Encoding
         * @notice Encoding handles Kroma's various different encoding schemes.
         */
        library Encoding {
            /**
             * @notice RLP encodes the L2 transaction that would be generated when a given deposit is sent
             *         to the L2 system. Useful for searching for a deposit in the L2 system. The
             *         transaction is prefixed with 0x7e to identify its EIP-2718 type.
             *
             * @param _tx User deposit transaction to encode.
             *
             * @return RLP encoded L2 deposit transaction.
             */
            function encodeDepositTransaction(Types.UserDepositTransaction memory _tx)
                internal
                pure
                returns (bytes memory)
            {
                bytes32 source = Hashing.hashDepositSource(_tx.l1BlockHash, _tx.logIndex);
                bytes[] memory raw = new bytes[](7);
                raw[0] = RLPWriter.writeBytes(abi.encodePacked(source));
                raw[1] = RLPWriter.writeAddress(_tx.from);
                raw[2] = _tx.isCreation ? RLPWriter.writeBytes("") : RLPWriter.writeAddress(_tx.to);
                raw[3] = RLPWriter.writeUint(_tx.mint);
                raw[4] = RLPWriter.writeUint(_tx.value);
                raw[5] = RLPWriter.writeUint(uint256(_tx.gasLimit));
                raw[6] = RLPWriter.writeBytes(_tx.data);
                return abi.encodePacked(uint8(0x7e), RLPWriter.writeList(raw));
            }
            /**
             * @notice Encodes the cross domain message based on the version that is encoded into the
             *         message nonce.
             *
             * @param _nonce    Message nonce with version encoded into the first two bytes.
             * @param _sender   Address of the sender of the message.
             * @param _target   Address of the target of the message.
             * @param _value    ETH value to send to the target.
             * @param _gasLimit Gas limit to use for the message.
             * @param _data     Data to send with the message.
             *
             * @return Encoded cross domain message.
             */
            function encodeCrossDomainMessage(
                uint256 _nonce,
                address _sender,
                address _target,
                uint256 _value,
                uint256 _gasLimit,
                bytes memory _data
            ) internal pure returns (bytes memory) {
                (, uint16 version) = decodeVersionedNonce(_nonce);
                if (version == 0) {
                    return encodeCrossDomainMessageV0(_nonce, _sender, _target, _value, _gasLimit, _data);
                } else {
                    revert("Encoding: unknown cross domain message version");
                }
            }
            /**
             * @notice Encodes a cross domain message based on the V0 (current) encoding.
             *
             * @param _nonce    Message nonce.
             * @param _sender   Address of the sender of the message.
             * @param _target   Address of the target of the message.
             * @param _value    ETH value to send to the target.
             * @param _gasLimit Gas limit to use for the message.
             * @param _data     Data to send with the message.
             *
             * @return Encoded cross domain message.
             */
            function encodeCrossDomainMessageV0(
                uint256 _nonce,
                address _sender,
                address _target,
                uint256 _value,
                uint256 _gasLimit,
                bytes memory _data
            ) internal pure returns (bytes memory) {
                return
                    abi.encodeWithSignature(
                        "relayMessage(uint256,address,address,uint256,uint256,bytes)",
                        _nonce,
                        _sender,
                        _target,
                        _value,
                        _gasLimit,
                        _data
                    );
            }
            /**
             * @notice Adds a version number into the first two bytes of a message nonce.
             *
             * @param _nonce   Message nonce to encode into.
             * @param _version Version number to encode into the message nonce.
             *
             * @return Message nonce with version encoded into the first two bytes.
             */
            function encodeVersionedNonce(uint240 _nonce, uint16 _version) internal pure returns (uint256) {
                uint256 nonce;
                assembly {
                    nonce := or(shl(240, _version), _nonce)
                }
                return nonce;
            }
            /**
             * @notice Pulls the version out of a version-encoded nonce.
             *
             * @param _nonce Message nonce with version encoded into the first two bytes.
             *
             * @return Nonce without encoded version.
             * @return Version of the message.
             */
            function decodeVersionedNonce(uint256 _nonce) internal pure returns (uint240, uint16) {
                uint240 nonce;
                uint16 version;
                assembly {
                    nonce := and(_nonce, 0x0000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff)
                    version := shr(240, _nonce)
                }
                return (nonce, version);
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        /**
         * @custom:attribution https://github.com/bakaoh/solidity-rlp-encode
         * @title RLPWriter
         * @author RLPWriter is a library for encoding Solidity types to RLP bytes. Adapted from Bakaoh's
         *         RLPEncode library (https://github.com/bakaoh/solidity-rlp-encode) with minor
         *         modifications to improve legibility.
         */
        library RLPWriter {
            /**
             * @notice RLP encodes a byte string.
             *
             * @param _in The byte string to encode.
             *
             * @return The RLP encoded string in bytes.
             */
            function writeBytes(bytes memory _in) internal pure returns (bytes memory) {
                bytes memory encoded;
                if (_in.length == 1 && uint8(_in[0]) < 128) {
                    encoded = _in;
                } else {
                    encoded = abi.encodePacked(_writeLength(_in.length, 128), _in);
                }
                return encoded;
            }
            /**
             * @notice RLP encodes a list of RLP encoded byte byte strings.
             *
             * @param _in The list of RLP encoded byte strings.
             *
             * @return The RLP encoded list of items in bytes.
             */
            function writeList(bytes[] memory _in) internal pure returns (bytes memory) {
                bytes memory list = _flatten(_in);
                return abi.encodePacked(_writeLength(list.length, 192), list);
            }
            /**
             * @notice RLP encodes a string.
             *
             * @param _in The string to encode.
             *
             * @return The RLP encoded string in bytes.
             */
            function writeString(string memory _in) internal pure returns (bytes memory) {
                return writeBytes(bytes(_in));
            }
            /**
             * @notice RLP encodes an address.
             *
             * @param _in The address to encode.
             *
             * @return The RLP encoded address in bytes.
             */
            function writeAddress(address _in) internal pure returns (bytes memory) {
                return writeBytes(abi.encodePacked(_in));
            }
            /**
             * @notice RLP encodes a uint.
             *
             * @param _in The uint256 to encode.
             *
             * @return The RLP encoded uint256 in bytes.
             */
            function writeUint(uint256 _in) internal pure returns (bytes memory) {
                return writeBytes(_toBinary(_in));
            }
            /**
             * @notice RLP encodes a bool.
             *
             * @param _in The bool to encode.
             *
             * @return The RLP encoded bool in bytes.
             */
            function writeBool(bool _in) internal pure returns (bytes memory) {
                bytes memory encoded = new bytes(1);
                encoded[0] = (_in ? bytes1(0x01) : bytes1(0x80));
                return encoded;
            }
            /**
             * @notice Encode the first byte and then the `len` in binary form if `length` is more than 55.
             *
             * @param _len    The length of the string or the payload.
             * @param _offset 128 if item is string, 192 if item is list.
             *
             * @return RLP encoded bytes.
             */
            function _writeLength(uint256 _len, uint256 _offset) private pure returns (bytes memory) {
                bytes memory encoded;
                if (_len < 56) {
                    encoded = new bytes(1);
                    encoded[0] = bytes1(uint8(_len) + uint8(_offset));
                } else {
                    uint256 lenLen;
                    uint256 i = 1;
                    while (_len / i != 0) {
                        lenLen++;
                        i *= 256;
                    }
                    encoded = new bytes(lenLen + 1);
                    encoded[0] = bytes1(uint8(lenLen) + uint8(_offset) + 55);
                    for (i = 1; i <= lenLen; i++) {
                        encoded[i] = bytes1(uint8((_len / (256**(lenLen - i))) % 256));
                    }
                }
                return encoded;
            }
            /**
             * @notice Encode integer in big endian binary form with no leading zeroes.
             *
             * @param _x The integer to encode.
             *
             * @return RLP encoded bytes.
             */
            function _toBinary(uint256 _x) private pure returns (bytes memory) {
                bytes memory b = abi.encodePacked(_x);
                uint256 i = 0;
                for (; i < 32; i++) {
                    if (b[i] != 0) {
                        break;
                    }
                }
                bytes memory res = new bytes(32 - i);
                for (uint256 j = 0; j < res.length; j++) {
                    res[j] = b[i++];
                }
                return res;
            }
            /**
             * @custom:attribution https://github.com/Arachnid/solidity-stringutils
             * @notice Copies a piece of memory to another location.
             *
             * @param _dest Destination location.
             * @param _src  Source location.
             * @param _len  Length of memory to copy.
             */
            function _memcpy(
                uint256 _dest,
                uint256 _src,
                uint256 _len
            ) private pure {
                uint256 dest = _dest;
                uint256 src = _src;
                uint256 len = _len;
                for (; len >= 32; len -= 32) {
                    assembly {
                        mstore(dest, mload(src))
                    }
                    dest += 32;
                    src += 32;
                }
                uint256 mask;
                unchecked {
                    mask = 256**(32 - len) - 1;
                }
                assembly {
                    let srcpart := and(mload(src), not(mask))
                    let destpart := and(mload(dest), mask)
                    mstore(dest, or(destpart, srcpart))
                }
            }
            /**
             * @custom:attribution https://github.com/sammayo/solidity-rlp-encoder
             * @notice Flattens a list of byte strings into one byte string.
             *
             * @param _list List of byte strings to flatten.
             *
             * @return The flattened byte string.
             */
            function _flatten(bytes[] memory _list) private pure returns (bytes memory) {
                if (_list.length == 0) {
                    return new bytes(0);
                }
                uint256 len;
                uint256 i = 0;
                for (; i < _list.length; i++) {
                    len += _list[i].length;
                }
                bytes memory flattened = new bytes(len);
                uint256 flattenedPtr;
                assembly {
                    flattenedPtr := add(flattened, 0x20)
                }
                for (i = 0; i < _list.length; i++) {
                    bytes memory item = _list[i];
                    uint256 listPtr;
                    assembly {
                        listPtr := add(item, 0x20)
                    }
                    _memcpy(flattenedPtr, listPtr, item.length);
                    flattenedPtr += _list[i].length;
                }
                return flattened;
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/Strings.sol)
        pragma solidity ^0.8.0;
        import "./math/Math.sol";
        import "./math/SignedMath.sol";
        /**
         * @dev String operations.
         */
        library Strings {
            bytes16 private constant _SYMBOLS = "0123456789abcdef";
            uint8 private constant _ADDRESS_LENGTH = 20;
            /**
             * @dev Converts a `uint256` to its ASCII `string` decimal representation.
             */
            function toString(uint256 value) internal pure returns (string memory) {
                unchecked {
                    uint256 length = Math.log10(value) + 1;
                    string memory buffer = new string(length);
                    uint256 ptr;
                    /// @solidity memory-safe-assembly
                    assembly {
                        ptr := add(buffer, add(32, length))
                    }
                    while (true) {
                        ptr--;
                        /// @solidity memory-safe-assembly
                        assembly {
                            mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                        }
                        value /= 10;
                        if (value == 0) break;
                    }
                    return buffer;
                }
            }
            /**
             * @dev Converts a `int256` to its ASCII `string` decimal representation.
             */
            function toString(int256 value) internal pure returns (string memory) {
                return string(abi.encodePacked(value < 0 ? "-" : "", toString(SignedMath.abs(value))));
            }
            /**
             * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
             */
            function toHexString(uint256 value) internal pure returns (string memory) {
                unchecked {
                    return toHexString(value, Math.log256(value) + 1);
                }
            }
            /**
             * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
             */
            function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
                bytes memory buffer = new bytes(2 * length + 2);
                buffer[0] = "0";
                buffer[1] = "x";
                for (uint256 i = 2 * length + 1; i > 1; --i) {
                    buffer[i] = _SYMBOLS[value & 0xf];
                    value >>= 4;
                }
                require(value == 0, "Strings: hex length insufficient");
                return string(buffer);
            }
            /**
             * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
             */
            function toHexString(address addr) internal pure returns (string memory) {
                return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
            }
            /**
             * @dev Returns true if the two strings are equal.
             */
            function equal(string memory a, string memory b) internal pure returns (bool) {
                return keccak256(bytes(a)) == keccak256(bytes(b));
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import {
            ReentrancyGuardUpgradeable
        } from "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";
        import { Math } from "@openzeppelin/contracts/utils/math/Math.sol";
        import { Constants } from "../libraries/Constants.sol";
        import { Predeploys } from "../libraries/Predeploys.sol";
        import { SafeCall } from "../libraries/SafeCall.sol";
        import { Types } from "../libraries/Types.sol";
        import { Semver } from "../universal/Semver.sol";
        import { ValidatorRewardVault } from "../L2/ValidatorRewardVault.sol";
        import { KromaPortal } from "./KromaPortal.sol";
        import { L2OutputOracle } from "./L2OutputOracle.sol";
        /**
         * @custom:proxied
         * @title ValidatorPool
         * @notice The ValidatorPool determines whether the validator is present and manages the validator's deposit.
         */
        contract ValidatorPool is ReentrancyGuardUpgradeable, Semver {
            /**
             * @notice The gas limit to use when rewarding validator in the ValidatorRewardVault on L2.
             *         This value is measured through simulation.
             */
            uint64 public constant VAULT_REWARD_GAS_LIMIT = 100000;
            /**
             * @notice The numerator of the tax.
             */
            uint128 public constant TAX_NUMERATOR = 20;
            /**
             * @notice The denominator of the tax.
             */
            uint128 public constant TAX_DENOMINATOR = 100;
            /**
             * @notice The address of the L2OutputOracle contract. Can be updated via upgrade.
             */
            L2OutputOracle public immutable L2_ORACLE;
            /**
             * @notice The address of the KromaPortal contract. Can be updated via upgrade.
             */
            KromaPortal public immutable PORTAL;
            /**
             * @notice The address of the SecurityCouncil contract. Can be updated via upgrade.
             */
            address public immutable SECURITY_COUNCIL;
            /**
             * @notice The address of the trusted validator. Can be updated via upgrade.
             */
            address public immutable TRUSTED_VALIDATOR;
            /**
             * @notice The required bond amount. Can be updated via upgrade.
             */
            uint128 public immutable REQUIRED_BOND_AMOUNT;
            /**
             * @notice The max number of unbonds when trying unbond.
             */
            uint256 public immutable MAX_UNBOND;
            /**
             * @notice The duration of a submission round for one output (in seconds).
             *         Note that there are two submission rounds for an output: PRIORITY ROUND and PUBLIC ROUND.
             */
            uint256 public immutable ROUND_DURATION;
            /**
             * @notice A mapping of balances.
             */
            mapping(address => uint256) internal balances;
            /**
             * @notice The bond corresponding to a specific output index.
             */
            mapping(uint256 => Types.Bond) internal bonds;
            /**
             * @notice The output index to unbond next.
             */
            uint256 internal nextUnbondOutputIndex;
            /**
             * @notice An array of validator addresses.
             */
            address[] internal validators;
            /**
             * @notice The index of the specific address in the validator array.
             */
            mapping(address => uint256) internal validatorIndexes;
            /**
             * @notice Address of the next validator with priority for submitting output.
             */
            address internal nextPriorityValidator;
            /**
             * @notice A mapping of pending bonds that have not yet been included in a bond.
             */
            mapping(uint256 => mapping(address => uint128)) internal pendingBonds;
            /**
             * @notice Emitted when a validator bonds.
             *
             * @param submitter   Address of submitter.
             * @param outputIndex Index of the L2 checkpoint output index.
             * @param amount      Amount of bonded.
             * @param expiresAt   The expiration timestamp of bond.
             */
            event Bonded(
                address indexed submitter,
                uint256 indexed outputIndex,
                uint128 amount,
                uint128 expiresAt
            );
            /**
             * @notice Emitted when the pending bond is added.
             *
             * @param outputIndex Index of the L2 checkpoint output.
             * @param challenger  Address of the challenger.
             * @param amount      Amount of bond added.
             */
            event PendingBondAdded(uint256 indexed outputIndex, address indexed challenger, uint128 amount);
            /**
             * @notice Emitted when the bond is increased.
             *
             * @param outputIndex Index of the L2 checkpoint output.
             * @param challenger  Address of the challenger.
             * @param amount      Amount of bond increased.
             */
            event BondIncreased(uint256 indexed outputIndex, address indexed challenger, uint128 amount);
            /**
             * @notice Emitted when the pending bond is released(refunded).
             *
             * @param outputIndex  Index of the L2 checkpoint output.
             * @param challenger   Address of the challenger.
             * @param recipient    Address to receive amount from a pending bond.
             * @param amount       Amount of bond released.
             */
            event PendingBondReleased(
                uint256 indexed outputIndex,
                address indexed challenger,
                address indexed recipient,
                uint128 amount
            );
            /**
             * @notice Emitted when a validator unbonds.
             *
             * @param outputIndex Index of the L2 checkpoint output.
             * @param recipient   Address of the recipient.
             * @param amount      Amount of unbonded.
             */
            event Unbonded(uint256 indexed outputIndex, address indexed recipient, uint128 amount);
            /**
             * @notice A modifier that only allows the Colosseum contract to call
             */
            modifier onlyColosseum() {
                require(msg.sender == L2_ORACLE.COLOSSEUM(), "ValidatorPool: sender is not Colosseum");
                _;
            }
            /**
             * @custom:semver 1.0.0
             *
             * @param _l2OutputOracle     Address of the L2OutputOracle.
             * @param _portal             Address of the KromaPortal.
             * @param _securityCouncil    Address of the security council.
             * @param _trustedValidator   Address of the trusted validator.
             * @param _requiredBondAmount The required bond amount.
             * @param _maxUnbond          The max number of unbonds when trying unbond.
             * @param _roundDuration      The duration of one submission round in seconds.
             */
            constructor(
                L2OutputOracle _l2OutputOracle,
                KromaPortal _portal,
                address _securityCouncil,
                address _trustedValidator,
                uint256 _requiredBondAmount,
                uint256 _maxUnbond,
                uint256 _roundDuration
            ) Semver(1, 0, 0) {
                L2_ORACLE = _l2OutputOracle;
                PORTAL = _portal;
                SECURITY_COUNCIL = _securityCouncil;
                TRUSTED_VALIDATOR = _trustedValidator;
                REQUIRED_BOND_AMOUNT = uint128(_requiredBondAmount);
                MAX_UNBOND = _maxUnbond;
                // Note that this value MUST be (SUBMISSION_INTERVAL * L2_BLOCK_TIME) / 2.
                ROUND_DURATION = _roundDuration;
                initialize();
            }
            /**
             * @notice Initializer.
             */
            function initialize() public initializer {
                __ReentrancyGuard_init_unchained();
            }
            /**
             * @notice Deposit ETH to be used as bond.
             */
            function deposit() external payable {
                _increaseBalance(msg.sender, msg.value);
            }
            /**
             * @notice Withdraw a given amount.
             *
             * @param _amount Amount to withdraw.
             */
            function withdraw(uint256 _amount) external nonReentrant {
                _decreaseBalance(msg.sender, _amount);
                bool success = SafeCall.call(msg.sender, gasleft(), _amount, "");
                require(success, "ValidatorPool: ETH transfer failed");
            }
            /**
             * @notice Bond asset corresponding to the given output index.
             *         This function is called when submitting output.
             *
             * @param _outputIndex Index of the L2 checkpoint output.
             * @param _expiresAt   The expiration timestamp of bond.
             */
            function createBond(uint256 _outputIndex, uint128 _expiresAt) external {
                require(msg.sender == address(L2_ORACLE), "ValidatorPool: sender is not L2OutputOracle");
                Types.Bond storage bond = bonds[_outputIndex];
                require(
                    bond.expiresAt == 0,
                    "ValidatorPool: bond of the given output index already exists"
                );
                // Unbond the bond of nextUnbondOutputIndex if available.
                _tryUnbond();
                address submitter = L2_ORACLE.getSubmitter(_outputIndex);
                _decreaseBalance(submitter, REQUIRED_BOND_AMOUNT);
                bond.amount = REQUIRED_BOND_AMOUNT;
                bond.expiresAt = _expiresAt;
                emit Bonded(submitter, _outputIndex, REQUIRED_BOND_AMOUNT, _expiresAt);
            }
            /**
             * @notice Adds a pending bond to the challenge corresponding to the given output index and challenger address.
             *         The pending bond is added to the bond when the challenge is proven or challenger is timed out,
             *         or refunded when the challenge is canceled.
             *
             * @param _outputIndex Index of the L2 checkpoint output.
             * @param _challenger  Address of the challenger.
             */
            function addPendingBond(uint256 _outputIndex, address _challenger) external onlyColosseum {
                Types.Bond storage bond = bonds[_outputIndex];
                require(
                    bond.expiresAt >= block.timestamp,
                    "ValidatorPool: the output is already finalized"
                );
                _decreaseBalance(_challenger, REQUIRED_BOND_AMOUNT);
                pendingBonds[_outputIndex][_challenger] = REQUIRED_BOND_AMOUNT;
                emit PendingBondAdded(_outputIndex, _challenger, REQUIRED_BOND_AMOUNT);
            }
            /**
             * @notice Releases the corresponding pending bond to the given output index and challenger address
             *         if a challenge is canceled.
             *
             * @param _outputIndex  Index of the L2 checkpoint output.
             * @param _challenger   Address of the challenger.
             * @param _recipient    Address to receive amount from a pending bond.
             */
            function releasePendingBond(
                uint256 _outputIndex,
                address _challenger,
                address _recipient
            ) external onlyColosseum {
                uint128 bonded = pendingBonds[_outputIndex][_challenger];
                require(bonded > 0, "ValidatorPool: the pending bond does not exist");
                delete pendingBonds[_outputIndex][_challenger];
                _increaseBalance(_recipient, bonded);
                emit PendingBondReleased(_outputIndex, _challenger, _recipient, bonded);
            }
            /**
             * @notice Increases the bond amount corresponding to the given output index by the pending bond amount.
             *         This is when taxes are charged, and note that taxes are a means of preventing collusive attacks by
             *         the asserter and challenger.
             *
             * @param _outputIndex Index of the L2 checkpoint output.
             * @param _challenger  Address of the challenger.
             */
            function increaseBond(uint256 _outputIndex, address _challenger) external onlyColosseum {
                Types.Bond storage bond = bonds[_outputIndex];
                require(
                    bond.expiresAt >= block.timestamp,
                    "ValidatorPool: the output is already finalized"
                );
                uint128 pendingBond = pendingBonds[_outputIndex][_challenger];
                require(pendingBond > 0, "ValidatorPool: the pending bond does not exist");
                uint128 tax = (pendingBond * TAX_NUMERATOR) / TAX_DENOMINATOR;
                uint128 increased = pendingBond - tax;
                delete pendingBonds[_outputIndex][_challenger];
                unchecked {
                    bond.amount += increased;
                    balances[SECURITY_COUNCIL] += tax;
                }
                emit BondIncreased(_outputIndex, _challenger, increased);
            }
            /**
             * @notice Attempt to unbond. Reverts if unbond is not possible.
             */
            function unbond() external {
                bool released = _tryUnbond();
                require(released, "ValidatorPool: no bond that can be unbond");
            }
            /**
             * @notice Attempts to unbond starting from nextUnbondOutputIndex and returns whether at least
             *         one unbond is executed. Tries unbond at most MAX_UNBOND number of bonds and sends
             *         a reward message to L2 for each unbond.
             *         Note that it updates the next priority validator using last unbond, and not updates
             *         when no unbond.
             *
             * @return Whether at least one unbond is executed.
             */
            function _tryUnbond() private returns (bool) {
                uint256 outputIndex = nextUnbondOutputIndex;
                uint128 bondAmount;
                Types.Bond storage bond;
                Types.CheckpointOutput memory output;
                uint256 unbondedNum = 0;
                for (; unbondedNum < MAX_UNBOND; ) {
                    bond = bonds[outputIndex];
                    bondAmount = bond.amount;
                    if (block.timestamp >= bond.expiresAt && bondAmount > 0) {
                        delete bonds[outputIndex];
                        output = L2_ORACLE.getL2Output(outputIndex);
                        _increaseBalance(output.submitter, bondAmount);
                        emit Unbonded(outputIndex, output.submitter, bondAmount);
                        // Send reward message to L2 ValidatorRewardVault.
                        _sendRewardMessageToL2Vault(output);
                        unchecked {
                            ++unbondedNum;
                            ++outputIndex;
                        }
                    } else {
                        break;
                    }
                }
                if (unbondedNum > 0) {
                    // Select the next priority validator.
                    _updatePriorityValidator(output.outputRoot);
                    unchecked {
                        nextUnbondOutputIndex = outputIndex;
                    }
                    return true;
                }
                return false;
            }
            /**
             * @notice Updates next priority validator address.
             *
             * @param _outputRoot The L2 output of the checkpoint block.
             */
            function _updatePriorityValidator(bytes32 _outputRoot) private {
                uint256 len = validators.length;
                if (len > 0) {
                    // TODO(pangssu): improve next validator selection
                    uint256 validatorIndex = uint256(
                        keccak256(
                            abi.encodePacked(
                                _outputRoot,
                                block.number,
                                block.coinbase,
                                block.difficulty,
                                blockhash(block.number - 1)
                            )
                        )
                    ) % len;
                    nextPriorityValidator = validators[validatorIndex];
                } else {
                    nextPriorityValidator = address(0);
                }
            }
            /**
             * @notice Sends reward message to ValidatorRewardVault contract on L2 using Portal.
             *
             * @param _output The finalized output.
             */
            function _sendRewardMessageToL2Vault(Types.CheckpointOutput memory _output) private {
                // Pay out rewards via L2 Vault now that the output is finalized.
                PORTAL.depositTransactionByValidatorPool(
                    Predeploys.VALIDATOR_REWARD_VAULT,
                    VAULT_REWARD_GAS_LIMIT,
                    abi.encodeWithSelector(
                        ValidatorRewardVault.reward.selector,
                        _output.submitter,
                        _output.l2BlockNumber
                    )
                );
            }
            /**
             * @notice Increases the balance of the given address. If the balance is greater than the required bond amount,
             *         add the given address to the validator set.
             *
             * @param _validator Address to increase the balance.
             * @param _amount    Amount of balance increased.
             */
            function _increaseBalance(address _validator, uint256 _amount) private {
                uint256 balance = balances[_validator] + _amount;
                if (balance >= REQUIRED_BOND_AMOUNT && !isValidator(_validator)) {
                    if (_validator != SECURITY_COUNCIL) {
                        validatorIndexes[_validator] = validators.length;
                        validators.push(_validator);
                    }
                }
                balances[_validator] = balance;
            }
            /**
             * @notice Deceases the balance of the given address. If the balance is less than the required bond amount,
             *         remove the given address from the validator set.
             *
             * @param _validator Address to decrease the balance.
             * @param _amount    Amount of balance decreased.
             */
            function _decreaseBalance(address _validator, uint256 _amount) private {
                uint256 balance = balances[_validator];
                require(balance >= _amount, "ValidatorPool: insufficient balances");
                balance = balance - _amount;
                if (balance < REQUIRED_BOND_AMOUNT && isValidator(_validator)) {
                    uint256 lastValidatorIndex = validators.length - 1;
                    if (lastValidatorIndex > 0) {
                        uint256 validatorIndex = validatorIndexes[_validator];
                        address lastValidator = validators[lastValidatorIndex];
                        validators[validatorIndex] = lastValidator;
                        validatorIndexes[lastValidator] = validatorIndex;
                    }
                    delete validatorIndexes[_validator];
                    validators.pop();
                }
                balances[_validator] = balance;
            }
            /**
             * @notice Returns the bond corresponding to the output index. Reverts if the bond does not exist.
             *
             * @param _outputIndex Index of the L2 checkpoint output.
             *
             * @return The bond data.
             */
            function getBond(uint256 _outputIndex) external view returns (Types.Bond memory) {
                Types.Bond storage bond = bonds[_outputIndex];
                require(bond.amount > 0 && bond.expiresAt > 0, "ValidatorPool: the bond does not exist");
                return bond;
            }
            /**
             * @notice Returns the pending bond corresponding to the output index and challenger address.
             *         Reverts if the pending bond does not exist.
             *
             * @param _outputIndex Index of the L2 checkpoint output.
             * @param _challenger  Address of the challenger.
             *
             * @return Amount of the pending bond.
             */
            function getPendingBond(uint256 _outputIndex, address _challenger)
                external
                view
                returns (uint128)
            {
                uint128 pendingBond = pendingBonds[_outputIndex][_challenger];
                require(pendingBond > 0, "ValidatorPool: the pending bond does not exist");
                return pendingBond;
            }
            /**
             * @notice Returns the balance of given address.
             *
             * @param _addr Address of validator.
             *
             * @return Balance of given address.
             */
            function balanceOf(address _addr) external view returns (uint256) {
                return balances[_addr];
            }
            /**
             * @notice Determines whether the given address is an active validator.
             *
             * @param _addr Address of validator.
             *
             * @return Whether the given address is an active validator.
             */
            function isValidator(address _addr) public view returns (bool) {
                if (validators.length == 0) {
                    return false;
                } else if (_addr == address(0)) {
                    return false;
                }
                uint256 index = validatorIndexes[_addr];
                return validators[index] == _addr;
            }
            /**
             * @notice Returns the number of validators.
             *
             * @return The number of validators.
             */
            function validatorCount() external view returns (uint256) {
                return validators.length;
            }
            /**
             * @notice Determines who can submit the L2 output next.
             *
             * @return The address of the validator.
             */
            function nextValidator() public view returns (address) {
                if (nextPriorityValidator != address(0)) {
                    uint256 l2BlockNumber = L2_ORACLE.nextBlockNumber();
                    uint256 l2Timestamp = L2_ORACLE.computeL2Timestamp(l2BlockNumber + 1);
                    if (block.timestamp >= l2Timestamp) {
                        uint256 elapsed = block.timestamp - l2Timestamp;
                        // If the current time exceeds one round time, it is a public round.
                        if (elapsed > ROUND_DURATION) {
                            return Constants.VALIDATOR_PUBLIC_ROUND_ADDRESS;
                        }
                    }
                    return nextPriorityValidator;
                } else {
                    return TRUSTED_VALIDATOR;
                }
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)
        pragma solidity ^0.8.0;
        /**
         * @dev Standard math utilities missing in the Solidity language.
         */
        library Math {
            enum Rounding {
                Down, // Toward negative infinity
                Up, // Toward infinity
                Zero // Toward zero
            }
            /**
             * @dev Returns the largest of two numbers.
             */
            function max(uint256 a, uint256 b) internal pure returns (uint256) {
                return a > b ? a : b;
            }
            /**
             * @dev Returns the smallest of two numbers.
             */
            function min(uint256 a, uint256 b) internal pure returns (uint256) {
                return a < b ? a : b;
            }
            /**
             * @dev Returns the average of two numbers. The result is rounded towards
             * zero.
             */
            function average(uint256 a, uint256 b) internal pure returns (uint256) {
                // (a + b) / 2 can overflow.
                return (a & b) + (a ^ b) / 2;
            }
            /**
             * @dev Returns the ceiling of the division of two numbers.
             *
             * This differs from standard division with `/` in that it rounds up instead
             * of rounding down.
             */
            function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
                // (a + b - 1) / b can overflow on addition, so we distribute.
                return a == 0 ? 0 : (a - 1) / b + 1;
            }
            /**
             * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
             * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
             * with further edits by Uniswap Labs also under MIT license.
             */
            function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
                unchecked {
                    // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
                    // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
                    // variables such that product = prod1 * 2^256 + prod0.
                    uint256 prod0; // Least significant 256 bits of the product
                    uint256 prod1; // Most significant 256 bits of the product
                    assembly {
                        let mm := mulmod(x, y, not(0))
                        prod0 := mul(x, y)
                        prod1 := sub(sub(mm, prod0), lt(mm, prod0))
                    }
                    // Handle non-overflow cases, 256 by 256 division.
                    if (prod1 == 0) {
                        // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                        // The surrounding unchecked block does not change this fact.
                        // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                        return prod0 / denominator;
                    }
                    // Make sure the result is less than 2^256. Also prevents denominator == 0.
                    require(denominator > prod1, "Math: mulDiv overflow");
                    ///////////////////////////////////////////////
                    // 512 by 256 division.
                    ///////////////////////////////////////////////
                    // Make division exact by subtracting the remainder from [prod1 prod0].
                    uint256 remainder;
                    assembly {
                        // Compute remainder using mulmod.
                        remainder := mulmod(x, y, denominator)
                        // Subtract 256 bit number from 512 bit number.
                        prod1 := sub(prod1, gt(remainder, prod0))
                        prod0 := sub(prod0, remainder)
                    }
                    // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
                    // See https://cs.stackexchange.com/q/138556/92363.
                    // Does not overflow because the denominator cannot be zero at this stage in the function.
                    uint256 twos = denominator & (~denominator + 1);
                    assembly {
                        // Divide denominator by twos.
                        denominator := div(denominator, twos)
                        // Divide [prod1 prod0] by twos.
                        prod0 := div(prod0, twos)
                        // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                        twos := add(div(sub(0, twos), twos), 1)
                    }
                    // Shift in bits from prod1 into prod0.
                    prod0 |= prod1 * twos;
                    // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
                    // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
                    // four bits. That is, denominator * inv = 1 mod 2^4.
                    uint256 inverse = (3 * denominator) ^ 2;
                    // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
                    // in modular arithmetic, doubling the correct bits in each step.
                    inverse *= 2 - denominator * inverse; // inverse mod 2^8
                    inverse *= 2 - denominator * inverse; // inverse mod 2^16
                    inverse *= 2 - denominator * inverse; // inverse mod 2^32
                    inverse *= 2 - denominator * inverse; // inverse mod 2^64
                    inverse *= 2 - denominator * inverse; // inverse mod 2^128
                    inverse *= 2 - denominator * inverse; // inverse mod 2^256
                    // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
                    // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
                    // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
                    // is no longer required.
                    result = prod0 * inverse;
                    return result;
                }
            }
            /**
             * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
             */
            function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
                uint256 result = mulDiv(x, y, denominator);
                if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
                    result += 1;
                }
                return result;
            }
            /**
             * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
             *
             * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
             */
            function sqrt(uint256 a) internal pure returns (uint256) {
                if (a == 0) {
                    return 0;
                }
                // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
                //
                // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
                // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
                //
                // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
                // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
                // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
                //
                // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
                uint256 result = 1 << (log2(a) >> 1);
                // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
                // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
                // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
                // into the expected uint128 result.
                unchecked {
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    return min(result, a / result);
                }
            }
            /**
             * @notice Calculates sqrt(a), following the selected rounding direction.
             */
            function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
                unchecked {
                    uint256 result = sqrt(a);
                    return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
                }
            }
            /**
             * @dev Return the log in base 2, rounded down, of a positive value.
             * Returns 0 if given 0.
             */
            function log2(uint256 value) internal pure returns (uint256) {
                uint256 result = 0;
                unchecked {
                    if (value >> 128 > 0) {
                        value >>= 128;
                        result += 128;
                    }
                    if (value >> 64 > 0) {
                        value >>= 64;
                        result += 64;
                    }
                    if (value >> 32 > 0) {
                        value >>= 32;
                        result += 32;
                    }
                    if (value >> 16 > 0) {
                        value >>= 16;
                        result += 16;
                    }
                    if (value >> 8 > 0) {
                        value >>= 8;
                        result += 8;
                    }
                    if (value >> 4 > 0) {
                        value >>= 4;
                        result += 4;
                    }
                    if (value >> 2 > 0) {
                        value >>= 2;
                        result += 2;
                    }
                    if (value >> 1 > 0) {
                        result += 1;
                    }
                }
                return result;
            }
            /**
             * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
             * Returns 0 if given 0.
             */
            function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
                unchecked {
                    uint256 result = log2(value);
                    return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
                }
            }
            /**
             * @dev Return the log in base 10, rounded down, of a positive value.
             * Returns 0 if given 0.
             */
            function log10(uint256 value) internal pure returns (uint256) {
                uint256 result = 0;
                unchecked {
                    if (value >= 10 ** 64) {
                        value /= 10 ** 64;
                        result += 64;
                    }
                    if (value >= 10 ** 32) {
                        value /= 10 ** 32;
                        result += 32;
                    }
                    if (value >= 10 ** 16) {
                        value /= 10 ** 16;
                        result += 16;
                    }
                    if (value >= 10 ** 8) {
                        value /= 10 ** 8;
                        result += 8;
                    }
                    if (value >= 10 ** 4) {
                        value /= 10 ** 4;
                        result += 4;
                    }
                    if (value >= 10 ** 2) {
                        value /= 10 ** 2;
                        result += 2;
                    }
                    if (value >= 10 ** 1) {
                        result += 1;
                    }
                }
                return result;
            }
            /**
             * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
             * Returns 0 if given 0.
             */
            function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
                unchecked {
                    uint256 result = log10(value);
                    return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
                }
            }
            /**
             * @dev Return the log in base 256, rounded down, of a positive value.
             * Returns 0 if given 0.
             *
             * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
             */
            function log256(uint256 value) internal pure returns (uint256) {
                uint256 result = 0;
                unchecked {
                    if (value >> 128 > 0) {
                        value >>= 128;
                        result += 16;
                    }
                    if (value >> 64 > 0) {
                        value >>= 64;
                        result += 8;
                    }
                    if (value >> 32 > 0) {
                        value >>= 32;
                        result += 4;
                    }
                    if (value >> 16 > 0) {
                        value >>= 16;
                        result += 2;
                    }
                    if (value >> 8 > 0) {
                        result += 1;
                    }
                }
                return result;
            }
            /**
             * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
             * Returns 0 if given 0.
             */
            function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
                unchecked {
                    uint256 result = log256(value);
                    return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Math } from "@openzeppelin/contracts/utils/math/Math.sol";
        import { SignedMath } from "@openzeppelin/contracts/utils/math/SignedMath.sol";
        import { FixedPointMathLib } from "@rari-capital/solmate/src/utils/FixedPointMathLib.sol";
        /**
         * @title Arithmetic
         * @notice Even more math than before.
         */
        library Arithmetic {
            /**
             * @notice Clamps a value between a minimum and maximum.
             *
             * @param _value The value to clamp.
             * @param _min   The minimum value.
             * @param _max   The maximum value.
             *
             * @return The clamped value.
             */
            function clamp(
                int256 _value,
                int256 _min,
                int256 _max
            ) internal pure returns (int256) {
                return SignedMath.min(SignedMath.max(_value, _min), _max);
            }
            /**
             * @notice Clamps a value between a minimum and maximum.
             *
             * @param _value The value to clamp.
             * @param _min   The minimum value.
             * @param _max   The maximum value.
             *
             * @return The clamped value.
             */
            function clamp(
                uint256 _value,
                uint256 _min,
                uint256 _max
            ) internal pure returns (uint256) {
                return Math.min(Math.max(_value, _min), _max);
            }
            /**
             * @notice (c)oefficient (d)enominator (exp)onentiation function.
             *         Returns the result of: c * (1 - 1/d)^exp.
             *
             * @param _coefficient Coefficient of the function.
             * @param _denominator Fractional denominator.
             * @param _exponent    Power function exponent.
             *
             * @return Result of c * (1 - 1/d)^exp.
             */
            function cdexp(
                int256 _coefficient,
                int256 _denominator,
                int256 _exponent
            ) internal pure returns (int256) {
                return
                    (_coefficient *
                        (FixedPointMathLib.powWad(1e18 - (1e18 / _denominator), _exponent * 1e18))) / 1e18;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { SafeCall } from "./SafeCall.sol";
        /**
         * @title Burn
         * @notice Utilities for burning stuff.
         */
        library Burn {
            /**
             * Burns a given amount of ETH.
             * Note that execution engine of Kroma does not support SELFDESTRUCT opcode, so it sends ETH to zero address.
             *
             * @param _amount Amount of ETH to burn.
             */
            function eth(uint256 _amount) internal {
                SafeCall.call(address(0), gasleft(), _amount, "");
            }
            /**
             * Burns a given amount of gas.
             *
             * @param _amount Amount of gas to burn.
             */
            function gas(uint256 _amount) internal view {
                uint256 i = 0;
                uint256 initialGas = gasleft();
                while (initialGas - gasleft() < _amount) {
                    ++i;
                }
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)
        pragma solidity ^0.8.0;
        import "../utils/ContextUpgradeable.sol";
        import "../proxy/utils/Initializable.sol";
        /**
         * @dev Contract module which provides a basic access control mechanism, where
         * there is an account (an owner) that can be granted exclusive access to
         * specific functions.
         *
         * By default, the owner account will be the one that deploys the contract. This
         * can later be changed with {transferOwnership}.
         *
         * This module is used through inheritance. It will make available the modifier
         * `onlyOwner`, which can be applied to your functions to restrict their use to
         * the owner.
         */
        abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
            address private _owner;
            event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
            /**
             * @dev Initializes the contract setting the deployer as the initial owner.
             */
            function __Ownable_init() internal onlyInitializing {
                __Ownable_init_unchained();
            }
            function __Ownable_init_unchained() internal onlyInitializing {
                _transferOwnership(_msgSender());
            }
            /**
             * @dev Throws if called by any account other than the owner.
             */
            modifier onlyOwner() {
                _checkOwner();
                _;
            }
            /**
             * @dev Returns the address of the current owner.
             */
            function owner() public view virtual returns (address) {
                return _owner;
            }
            /**
             * @dev Throws if the sender is not the owner.
             */
            function _checkOwner() internal view virtual {
                require(owner() == _msgSender(), "Ownable: caller is not the owner");
            }
            /**
             * @dev Leaves the contract without owner. It will not be possible to call
             * `onlyOwner` functions. Can only be called by the current owner.
             *
             * NOTE: Renouncing ownership will leave the contract without an owner,
             * thereby disabling any functionality that is only available to the owner.
             */
            function renounceOwnership() public virtual onlyOwner {
                _transferOwnership(address(0));
            }
            /**
             * @dev Transfers ownership of the contract to a new account (`newOwner`).
             * Can only be called by the current owner.
             */
            function transferOwnership(address newOwner) public virtual onlyOwner {
                require(newOwner != address(0), "Ownable: new owner is the zero address");
                _transferOwnership(newOwner);
            }
            /**
             * @dev Transfers ownership of the contract to a new account (`newOwner`).
             * Internal function without access restriction.
             */
            function _transferOwnership(address newOwner) internal virtual {
                address oldOwner = _owner;
                _owner = newOwner;
                emit OwnershipTransferred(oldOwner, newOwner);
            }
            /**
             * @dev This empty reserved space is put in place to allow future versions to add new
             * variables without shifting down storage in the inheritance chain.
             * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
             */
            uint256[49] private __gap;
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        /**
         * @title Bytes
         * @notice Bytes is a library for manipulating byte arrays.
         */
        library Bytes {
            /**
             * @notice Compares two byte arrays by comparing their keccak256 hashes.
             *
             * @param _bytes First byte array to compare.
             * @param _other Second byte array to compare.
             *
             * @return True if the two byte arrays are equal, false otherwise.
             */
            function equal(bytes memory _bytes, bytes memory _other) internal pure returns (bool) {
                return keccak256(_bytes) == keccak256(_other);
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        /**
         * @title NodeReader
         * @notice NodeReader is a library for reading ZKTrie Node.
         */
        library NodeReader {
            /**
             * @notice Node types.
             *         See https://github.com/kroma-network/zktrie/blob/main/types/README.md.
             *
             * @custom:value MIDDLE Represents a middle node.
             * @custom:value LEAF   Represents a leaf node.
             * @custom:value EMPTY  Represents a empty node.
             * @custom:value ROOT   Represents a root node.
             */
            enum NodeType {
                MIDDLE,
                LEAF,
                EMPTY,
                ROOT
            }
            /**
             * @notice Struct representing a Node.
             *         See https://github.com/kroma-network/zktrie/blob/main/types/README.md.
             */
            struct Node {
                NodeType nodeType;
                bytes32 childL;
                bytes32 childR;
                bytes32 nodeKey;
                bytes32[] valuePreimage;
                uint32 compressedFlags;
                bytes32 valueHash;
                bytes32 keyPreimage;
            }
            /**
             * @notice Struct representing an Item.
             */
            struct Item {
                bytes ptr;
                uint256 len;
            }
            /**
             * @notice Converts bytes to Item.
             *
             * @param _bytes bytes to convert.
             *
             * @return Item referencing _bytes.
             */
            function toItem(bytes memory _bytes) internal pure returns (Item memory) {
                bytes memory ptr;
                assembly {
                    ptr := add(_bytes, 32)
                }
                return Item({ ptr: ptr, len: _bytes.length });
            }
            /**
             * @notice Reads an Item into an uint8.
             *         Internal ptr and length is updated automatically.
             *
             * @param _item Item to read.
             *
             * @return An uint8 value.
             */
            function readUint8(Item memory _item) internal pure returns (uint8) {
                require(_item.len >= 1, "NodeReader: too short for uint8");
                bytes memory newPtr;
                bytes memory ptr = _item.ptr;
                uint8 ret;
                assembly {
                    ret := shr(248, mload(ptr))
                    newPtr := add(ptr, 1)
                }
                _item.ptr = newPtr;
                _item.len -= 1;
                return ret;
            }
            /**
             * @notice Reads an Item into compressed flags and length of values.
             *         Internal ptr and length is updated automatically.
             *
             * @param _item Item to read.
             *
             * @return Compressed flags.
             * @return Length of values.
             */
            function readCompressedFlags(Item memory _item) internal pure returns (uint32, uint8) {
                require(_item.len >= 4, "NodeReader: too short for uint32");
                bytes memory newPtr;
                bytes memory ptr = _item.ptr;
                uint32 temp;
                uint8 flag;
                uint8 len;
                assembly {
                    temp := mload(ptr)
                    len := shr(248, temp)
                    flag := shr(240, temp)
                    newPtr := add(ptr, 4)
                }
                _item.ptr = newPtr;
                _item.len -= 4;
                return (flag, len);
            }
            /**
             * @notice Reads an Item into a bytes32.
             *         Internal ptr and length is updated automatically.
             *
             * @param _item Item to read.
             *
             * @return A bytes32 value.
             */
            function readBytes32(Item memory _item) internal pure returns (bytes32) {
                require(_item.len >= 32, "NodeReader: too short for bytes32");
                bytes memory newPtr;
                bytes memory ptr = _item.ptr;
                bytes32 ret;
                assembly {
                    ret := mload(ptr)
                    newPtr := add(ptr, 32)
                }
                _item.ptr = newPtr;
                _item.len -= 32;
                return ret;
            }
            /**
             * @notice Reads an Item by n bytes into a bytes32.
             *         Internal ptr and length is updated automatically.
             *
             * @param _item Item to read.
             *
             * @return A bytes32 value.
             */
            function readBytesN(Item memory _item, uint256 _length) internal pure returns (bytes32) {
                require(_item.len >= _length, "NodeReader: too short for n bytes");
                bytes memory newPtr;
                bytes memory ptr = _item.ptr;
                bytes32 ret;
                uint256 to = 256 - _length * 8;
                assembly {
                    newPtr := add(ptr, _length)
                    ret := shr(to, mload(ptr))
                }
                _item.ptr = newPtr;
                _item.len -= _length;
                return ret;
            }
            /**
             * @notice Reads bytes into a Node.
             *
             * @param _proof Bytes to read.
             *
             * @return A decoded Node.
             */
            function readNode(bytes memory _proof) internal pure returns (Node memory) {
                Node memory node;
                Item memory item = toItem(_proof);
                uint256 nodeType = readUint8(item);
                if (nodeType == uint256(NodeType.MIDDLE)) {
                    // TODO(chokobole): Do the length check as much as possible at once and read the bytes.
                    node.childL = readBytes32(item);
                    node.childR = readBytes32(item);
                } else if (nodeType == uint256(NodeType.LEAF)) {
                    // TODO(chokobole): Do the length check as much as possible at once and read the bytes.
                    node.nodeKey = readBytes32(item);
                    (uint32 compressedFlags, uint256 valuePreimageLen) = readCompressedFlags(item);
                    require((compressedFlags == 1 && valuePreimageLen == 1) || (compressedFlags == 4 && valuePreimageLen == 4), "NodeReader: invalid compressedFlags");
                    node.compressedFlags = compressedFlags;
                    node.valuePreimage = new bytes32[](valuePreimageLen);
                    for (uint256 i = 0; i < valuePreimageLen; ) {
                        node.valuePreimage[i] = readBytes32(item);
                        unchecked {
                            ++i;
                        }
                    }
                    uint256 keyPreimageLen = readUint8(item);
                    if (keyPreimageLen > 0) {
                        node.keyPreimage = readBytesN(item, keyPreimageLen);
                    }
                } else if (nodeType == uint256(NodeType.EMPTY)) {
                    // Do nothing.
                } else if (nodeType == uint256(NodeType.ROOT)) {
                    revert("NodeReader: unexpected root node type");
                } else {
                    revert("NodeReader: invalid node type");
                }
                node.nodeType = NodeType(nodeType);
                return node;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        /**
         * @title IZKMerkleTrie
         */
        interface IZKMerkleTrie {
            /**
             * @notice Verifies a proof that a given key/value pair is present in the trie.
             *
             * @param _key    Key of the node to search for, as a hex string.
             * @param _value  Value of the node to search for, as a hex string.
             * @param _proofs Merkle trie inclusion proof for the desired node.
             * @param _root   Known root of the Merkle trie. Used to verify that the included proof is
             *                correctly constructed.
             *
             * @return Whether or not the proof is valid.
             */
            function verifyInclusionProof(
                bytes32 _key,
                bytes memory _value,
                bytes[] memory _proofs,
                bytes32 _root
            ) external view returns (bool);
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
        import { Bytes32 } from "../libraries/Bytes32.sol";
        /**
         * @title IPoseidon2
         */
        interface IPoseidon2 {
            function poseidon(bytes32[2] memory inputs) external pure returns (bytes32);
        }
        /**
         * @custom:proxied
         * @title ZKTrieHasher
         * @notice The ZKTrieHasher is contract which can produce a hash according to ZKTrie.
         *         This owns an interface of Poseidon2 that is required to compute hash used by ZKTrie.
         */
        contract ZKTrieHasher {
            /**
             * @notice Poseidon2 contract generated by circomlibjs.
             */
            IPoseidon2 public immutable POSEIDON2;
            /**
             * @param _poseidon2 The address of poseidon2 contract.
             */
            constructor(address _poseidon2) {
                POSEIDON2 = IPoseidon2(_poseidon2);
            }
            /**
             * @notice Computes a hash of values.
             *
             * @param _compressedFlags Compressed flags.
             * @param _values          Values.
             *
             * @return A hash of values.
             */
            function _valueHash(uint32 _compressedFlags, bytes32[] memory _values)
                internal
                view
                returns (bytes32)
            {
                require(_values.length >= 1, "ZKTrieHasher: too few values for _valueHash");
                bytes32[] memory ret = new bytes32[](_values.length);
                for (uint256 i = 0; i < _values.length; ) {
                    if ((_compressedFlags & (1 << i)) != 0) {
                        ret[i] = _hashElem(_values[i]);
                    } else {
                        ret[i] = _values[i];
                    }
                    unchecked {
                        ++i;
                    }
                }
                if (_values.length < 2) {
                    return ret[0];
                }
                return _hashElems(ret);
            }
            /**
             * @notice Computes a hash of an element.
             *
             * @param _elem Bytes32 to be hashed.
             *
             * @return A hash of an element.
             */
            function _hashElem(bytes32 _elem) internal view returns (bytes32) {
                (bytes32 high, bytes32 low) = Bytes32.split(_elem);
                return POSEIDON2.poseidon([high, low]);
            }
            /**
             * @notice Computes a root hash of elements tree.
             *
             * @param _elems Bytes32 array to be hashed.
             *
             * @return A hash of elements tree.
             */
            function _hashElems(bytes32[] memory _elems) internal view returns (bytes32) {
                require(_elems.length >= 4, "ZKTrieHasher: too few values for _hashElems");
                IPoseidon2 iposeidon = POSEIDON2;
                uint256 idx;
                uint256 adjacent_idx;
                uint256 adjacent_offset = 1;
                uint256 jump = 2;
                uint256 length = _elems.length;
                for (; adjacent_offset < length;) {
                    for (idx = 0; idx < length;) {
                        unchecked {
                            adjacent_idx = idx + adjacent_offset;
                        }
                        if (adjacent_idx < length) {
                            _elems[idx] = iposeidon.poseidon( [_elems[idx], _elems[adjacent_idx]] );
                        }
                        unchecked {
                            idx += jump;
                        }
                    }
                    adjacent_offset = jump;
                    jump <<= 1;
                }
                return _elems[0];
            }
            /**
             * @notice Computes a root hash of 2 elements.
             *
             * @param left_leaf  Bytes32 left leaf to be hashed.
             * @param right_leaf Bytes32 right leaf to be hashed.
             *
             * @return A hash of 2 elements.
             */
            function _hashFixed2Elems(bytes32 left_leaf, bytes32 right_leaf) internal view returns (bytes32) {
                return POSEIDON2.poseidon([left_leaf, right_leaf]);
            }
           /**
             * @notice Computes a root hash of 3 elements.
             *
             * @param left_leaf  Bytes32 left leaf to be hashed.
             * @param right_leaf Bytes32 right leaf to be hashed.
             * @param up_leaf    Bytes32 up leaf to be hashed with left||right hash.
             *
             * @return A hash of 3 elements.
             */
            function _hashFixed3Elems(bytes32 left_leaf, bytes32 right_leaf, bytes32 up_leaf) internal view returns (bytes32) {
                IPoseidon2 iposeidon = POSEIDON2;
                left_leaf = iposeidon.poseidon([left_leaf, right_leaf]);
                return iposeidon.poseidon([left_leaf, up_leaf]);
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SignedMath.sol)
        pragma solidity ^0.8.0;
        /**
         * @dev Standard signed math utilities missing in the Solidity language.
         */
        library SignedMath {
            /**
             * @dev Returns the largest of two signed numbers.
             */
            function max(int256 a, int256 b) internal pure returns (int256) {
                return a > b ? a : b;
            }
            /**
             * @dev Returns the smallest of two signed numbers.
             */
            function min(int256 a, int256 b) internal pure returns (int256) {
                return a < b ? a : b;
            }
            /**
             * @dev Returns the average of two signed numbers without overflow.
             * The result is rounded towards zero.
             */
            function average(int256 a, int256 b) internal pure returns (int256) {
                // Formula from the book "Hacker's Delight"
                int256 x = (a & b) + ((a ^ b) >> 1);
                return x + (int256(uint256(x) >> 255) & (a ^ b));
            }
            /**
             * @dev Returns the absolute unsigned value of a signed value.
             */
            function abs(int256 n) internal pure returns (uint256) {
                unchecked {
                    // must be unchecked in order to support `n = type(int256).min`
                    return uint256(n >= 0 ? n : -n);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (security/ReentrancyGuard.sol)
        pragma solidity ^0.8.0;
        import "../proxy/utils/Initializable.sol";
        /**
         * @dev Contract module that helps prevent reentrant calls to a function.
         *
         * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
         * available, which can be applied to functions to make sure there are no nested
         * (reentrant) calls to them.
         *
         * Note that because there is a single `nonReentrant` guard, functions marked as
         * `nonReentrant` may not call one another. This can be worked around by making
         * those functions `private`, and then adding `external` `nonReentrant` entry
         * points to them.
         *
         * TIP: If you would like to learn more about reentrancy and alternative ways
         * to protect against it, check out our blog post
         * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
         */
        abstract contract ReentrancyGuardUpgradeable is Initializable {
            // Booleans are more expensive than uint256 or any type that takes up a full
            // word because each write operation emits an extra SLOAD to first read the
            // slot's contents, replace the bits taken up by the boolean, and then write
            // back. This is the compiler's defense against contract upgrades and
            // pointer aliasing, and it cannot be disabled.
            // The values being non-zero value makes deployment a bit more expensive,
            // but in exchange the refund on every call to nonReentrant will be lower in
            // amount. Since refunds are capped to a percentage of the total
            // transaction's gas, it is best to keep them low in cases like this one, to
            // increase the likelihood of the full refund coming into effect.
            uint256 private constant _NOT_ENTERED = 1;
            uint256 private constant _ENTERED = 2;
            uint256 private _status;
            function __ReentrancyGuard_init() internal onlyInitializing {
                __ReentrancyGuard_init_unchained();
            }
            function __ReentrancyGuard_init_unchained() internal onlyInitializing {
                _status = _NOT_ENTERED;
            }
            /**
             * @dev Prevents a contract from calling itself, directly or indirectly.
             * Calling a `nonReentrant` function from another `nonReentrant`
             * function is not supported. It is possible to prevent this from happening
             * by making the `nonReentrant` function external, and making it call a
             * `private` function that does the actual work.
             */
            modifier nonReentrant() {
                _nonReentrantBefore();
                _;
                _nonReentrantAfter();
            }
            function _nonReentrantBefore() private {
                // On the first call to nonReentrant, _status will be _NOT_ENTERED
                require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
                // Any calls to nonReentrant after this point will fail
                _status = _ENTERED;
            }
            function _nonReentrantAfter() private {
                // By storing the original value once again, a refund is triggered (see
                // https://eips.ethereum.org/EIPS/eip-2200)
                _status = _NOT_ENTERED;
            }
            /**
             * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
             * `nonReentrant` function in the call stack.
             */
            function _reentrancyGuardEntered() internal view returns (bool) {
                return _status == _ENTERED;
            }
            /**
             * @dev This empty reserved space is put in place to allow future versions to add new
             * variables without shifting down storage in the inheritance chain.
             * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
             */
            uint256[49] private __gap;
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        /**
         * @title Predeploys
         * @notice Contains constant addresses for contracts that are pre-deployed to the L2 system.
         */
        library Predeploys {
            /**
             * @notice Address of the ProxyAdmin predeploy.
             */
            address internal constant PROXY_ADMIN = 0x4200000000000000000000000000000000000000;
            /**
             * @notice Address of the L1Block predeploy.
             */
            address internal constant L1_BLOCK_ATTRIBUTES = 0x4200000000000000000000000000000000000002;
            /**
             * @notice Address of the L2ToL1MessagePasser predeploy.
             */
            address internal constant L2_TO_L1_MESSAGE_PASSER = 0x4200000000000000000000000000000000000003;
            /**
             * @notice Address of the L2CrossDomainMessenger predeploy.
             */
            address internal constant L2_CROSS_DOMAIN_MESSENGER =
                0x4200000000000000000000000000000000000004;
            /**
             * @notice Address of the GasPriceOracle predeploy. Includes fee information
             *         and helpers for computing the L1 portion of the transaction fee.
             */
            address internal constant GAS_PRICE_ORACLE = 0x4200000000000000000000000000000000000005;
            /**
             * @notice Address of the ProtocolVault predeploy.
             */
            address internal constant PROTOCOL_VAULT = 0x4200000000000000000000000000000000000006;
            /**
             * @notice Address of the ProposerRewardVault predeploy.
             */
            address internal constant PROPOSER_REWARD_VAULT = 0x4200000000000000000000000000000000000007;
            /**
             * @notice Address of the ValidatorRewardVault predeploy.
             */
            address internal constant VALIDATOR_REWARD_VAULT = 0x4200000000000000000000000000000000000008;
            /**
             * @notice Address of the L2StandardBridge predeploy.
             */
            address internal constant L2_STANDARD_BRIDGE = 0x4200000000000000000000000000000000000009;
            /**
             * @notice Address of the L2ERC721Bridge predeploy.
             */
            address internal constant L2_ERC721_BRIDGE = 0x420000000000000000000000000000000000000A;
            /**
             * @notice Address of the KromaMintableERC20Factory predeploy.
             */
            address internal constant KROMA_MINTABLE_ERC20_FACTORY =
                0x420000000000000000000000000000000000000B;
            /**
             * @notice Address of the KromaMintableERC721Factory predeploy.
             */
            address internal constant KROMA_MINTABLE_ERC721_FACTORY =
                0x420000000000000000000000000000000000000c;
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { L2StandardBridge } from "../L2/L2StandardBridge.sol";
        import { Predeploys } from "../libraries/Predeploys.sol";
        import { FeeVault } from "../universal/FeeVault.sol";
        import { Semver } from "../universal/Semver.sol";
        import { AddressAliasHelper } from "../vendor/AddressAliasHelper.sol";
        /**
         * @custom:proxied
         * @custom:predeploy 0x4200000000000000000000000000000000000008
         * @title ValidatorRewardVault
         * @notice The ValidatorRewardVault accumulates transaction fees and pays rewards to validators.
         */
        contract ValidatorRewardVault is FeeVault, Semver {
            /**
             * @notice Address of the ValidatorPool contract on L1.
             */
            address public immutable VALIDATOR_POOL;
            /**
             * @notice A value to divide the vault balance by when determining the reward amount.
             */
            uint256 public immutable REWARD_DIVIDER;
            /**
             * @notice The reward balance that the validator is eligible to receive.
             */
            mapping(address => uint256) internal rewards;
            /**
             * @notice A mapping of whether the reward corresponding to the L2 block number has been paid.
             */
            mapping(uint256 => bool) internal isPaid;
            /**
             * @notice The amount of determined as rewards.
             */
            uint256 public totalReserved;
            /**
             * @notice Emitted when the balance of a validator has increased.
             *
             * @param validator     Address of the validator.
             * @param l2BlockNumber The L2 block number of the output root.
             * @param amount        Amount of the reward.
             */
            event Rewarded(address indexed validator, uint256 indexed l2BlockNumber, uint256 amount);
            /**
             * @custom:semver 1.0.0
             *
             * @param _validatorPool Address of the ValidatorPool contract on L1.
             * @param _rewardDivider A value to divide the vault balance by when determining the reward amount.
             */
            constructor(address _validatorPool, uint256 _rewardDivider)
                FeeVault(address(0), 10 ether)
                Semver(1, 0, 0)
            {
                VALIDATOR_POOL = _validatorPool;
                REWARD_DIVIDER = _rewardDivider;
            }
            /**
             * @notice Rewards the validator for submitting the output.
             *         ValidatorPool contract on L1 calls this function over the portal when output is finalized.
             *
             * @param _validator     Address of the validator.
             * @param _l2BlockNumber The L2 block number of the output root.
             */
            function reward(address _validator, uint256 _l2BlockNumber) external {
                require(
                    AddressAliasHelper.undoL1ToL2Alias(msg.sender) == VALIDATOR_POOL,
                    "ValidatorRewardVault: function can only be called from the ValidatorPool"
                );
                require(_validator != address(0), "ValidatorRewardVault: validator address cannot be 0");
                require(
                    !isPaid[_l2BlockNumber],
                    "ValidatorRewardVault: the reward has already been paid for the L2 block number"
                );
                uint256 amount = _determineRewardAmount();
                unchecked {
                    totalReserved += amount;
                    rewards[_validator] += amount;
                }
                isPaid[_l2BlockNumber] = true;
                emit Rewarded(_validator, _l2BlockNumber, amount);
            }
            /**
             * @notice Withdraws all of the sender's balance.
             *         Reverts if the balance is less than the minimum withdrawal amount.
             */
            function withdraw() external override {
                uint256 balance = rewards[msg.sender];
                require(
                    balance >= MIN_WITHDRAWAL_AMOUNT,
                    "ValidatorRewardVault: withdrawal amount must be greater than minimum withdrawal amount"
                );
                rewards[msg.sender] = 0;
                unchecked {
                    totalReserved -= balance;
                    totalProcessed += balance;
                }
                emit Withdrawal(balance, msg.sender, msg.sender);
                L2StandardBridge(payable(Predeploys.L2_STANDARD_BRIDGE)).bridgeETHTo{ value: balance }(
                    msg.sender,
                    WITHDRAWAL_MIN_GAS,
                    bytes("")
                );
            }
            /**
             * @notice Determines the reward amount.
             *
             * @return Amount of the reward.
             */
            function _determineRewardAmount() internal view returns (uint256) {
                return (address(this).balance - totalReserved) / REWARD_DIVIDER;
            }
            /**
             * @notice Returns the reward balance of the given address.
             *
             * @param _addr Address to lookup.
             *
             * @return The reward balance of the given address.
             */
            function balanceOf(address _addr) external view returns (uint256) {
                return rewards[_addr];
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity >=0.8.0;
        /// @notice Arithmetic library with operations for fixed-point numbers.
        /// @author Solmate (https://github.com/Rari-Capital/solmate/blob/main/src/utils/FixedPointMathLib.sol)
        library FixedPointMathLib {
            /*//////////////////////////////////////////////////////////////
                            SIMPLIFIED FIXED POINT OPERATIONS
            //////////////////////////////////////////////////////////////*/
            uint256 internal constant WAD = 1e18; // The scalar of ETH and most ERC20s.
            function mulWadDown(uint256 x, uint256 y) internal pure returns (uint256) {
                return mulDivDown(x, y, WAD); // Equivalent to (x * y) / WAD rounded down.
            }
            function mulWadUp(uint256 x, uint256 y) internal pure returns (uint256) {
                return mulDivUp(x, y, WAD); // Equivalent to (x * y) / WAD rounded up.
            }
            function divWadDown(uint256 x, uint256 y) internal pure returns (uint256) {
                return mulDivDown(x, WAD, y); // Equivalent to (x * WAD) / y rounded down.
            }
            function divWadUp(uint256 x, uint256 y) internal pure returns (uint256) {
                return mulDivUp(x, WAD, y); // Equivalent to (x * WAD) / y rounded up.
            }
            function powWad(int256 x, int256 y) internal pure returns (int256) {
                // Equivalent to x to the power of y because x ** y = (e ** ln(x)) ** y = e ** (ln(x) * y)
                return expWad((lnWad(x) * y) / int256(WAD)); // Using ln(x) means x must be greater than 0.
            }
            function expWad(int256 x) internal pure returns (int256 r) {
                unchecked {
                    // When the result is < 0.5 we return zero. This happens when
                    // x <= floor(log(0.5e18) * 1e18) ~ -42e18
                    if (x <= -42139678854452767551) return 0;
                    // When the result is > (2**255 - 1) / 1e18 we can not represent it as an
                    // int. This happens when x >= floor(log((2**255 - 1) / 1e18) * 1e18) ~ 135.
                    if (x >= 135305999368893231589) revert("EXP_OVERFLOW");
                    // x is now in the range (-42, 136) * 1e18. Convert to (-42, 136) * 2**96
                    // for more intermediate precision and a binary basis. This base conversion
                    // is a multiplication by 1e18 / 2**96 = 5**18 / 2**78.
                    x = (x << 78) / 5**18;
                    // Reduce range of x to (-½ ln 2, ½ ln 2) * 2**96 by factoring out powers
                    // of two such that exp(x) = exp(x') * 2**k, where k is an integer.
                    // Solving this gives k = round(x / log(2)) and x' = x - k * log(2).
                    int256 k = ((x << 96) / 54916777467707473351141471128 + 2**95) >> 96;
                    x = x - k * 54916777467707473351141471128;
                    // k is in the range [-61, 195].
                    // Evaluate using a (6, 7)-term rational approximation.
                    // p is made monic, we'll multiply by a scale factor later.
                    int256 y = x + 1346386616545796478920950773328;
                    y = ((y * x) >> 96) + 57155421227552351082224309758442;
                    int256 p = y + x - 94201549194550492254356042504812;
                    p = ((p * y) >> 96) + 28719021644029726153956944680412240;
                    p = p * x + (4385272521454847904659076985693276 << 96);
                    // We leave p in 2**192 basis so we don't need to scale it back up for the division.
                    int256 q = x - 2855989394907223263936484059900;
                    q = ((q * x) >> 96) + 50020603652535783019961831881945;
                    q = ((q * x) >> 96) - 533845033583426703283633433725380;
                    q = ((q * x) >> 96) + 3604857256930695427073651918091429;
                    q = ((q * x) >> 96) - 14423608567350463180887372962807573;
                    q = ((q * x) >> 96) + 26449188498355588339934803723976023;
                    assembly {
                        // Div in assembly because solidity adds a zero check despite the unchecked.
                        // The q polynomial won't have zeros in the domain as all its roots are complex.
                        // No scaling is necessary because p is already 2**96 too large.
                        r := sdiv(p, q)
                    }
                    // r should be in the range (0.09, 0.25) * 2**96.
                    // We now need to multiply r by:
                    // * the scale factor s = ~6.031367120.
                    // * the 2**k factor from the range reduction.
                    // * the 1e18 / 2**96 factor for base conversion.
                    // We do this all at once, with an intermediate result in 2**213
                    // basis, so the final right shift is always by a positive amount.
                    r = int256((uint256(r) * 3822833074963236453042738258902158003155416615667) >> uint256(195 - k));
                }
            }
            function lnWad(int256 x) internal pure returns (int256 r) {
                unchecked {
                    require(x > 0, "UNDEFINED");
                    // We want to convert x from 10**18 fixed point to 2**96 fixed point.
                    // We do this by multiplying by 2**96 / 10**18. But since
                    // ln(x * C) = ln(x) + ln(C), we can simply do nothing here
                    // and add ln(2**96 / 10**18) at the end.
                    // Reduce range of x to (1, 2) * 2**96
                    // ln(2^k * x) = k * ln(2) + ln(x)
                    int256 k = int256(log2(uint256(x))) - 96;
                    x <<= uint256(159 - k);
                    x = int256(uint256(x) >> 159);
                    // Evaluate using a (8, 8)-term rational approximation.
                    // p is made monic, we will multiply by a scale factor later.
                    int256 p = x + 3273285459638523848632254066296;
                    p = ((p * x) >> 96) + 24828157081833163892658089445524;
                    p = ((p * x) >> 96) + 43456485725739037958740375743393;
                    p = ((p * x) >> 96) - 11111509109440967052023855526967;
                    p = ((p * x) >> 96) - 45023709667254063763336534515857;
                    p = ((p * x) >> 96) - 14706773417378608786704636184526;
                    p = p * x - (795164235651350426258249787498 << 96);
                    // We leave p in 2**192 basis so we don't need to scale it back up for the division.
                    // q is monic by convention.
                    int256 q = x + 5573035233440673466300451813936;
                    q = ((q * x) >> 96) + 71694874799317883764090561454958;
                    q = ((q * x) >> 96) + 283447036172924575727196451306956;
                    q = ((q * x) >> 96) + 401686690394027663651624208769553;
                    q = ((q * x) >> 96) + 204048457590392012362485061816622;
                    q = ((q * x) >> 96) + 31853899698501571402653359427138;
                    q = ((q * x) >> 96) + 909429971244387300277376558375;
                    assembly {
                        // Div in assembly because solidity adds a zero check despite the unchecked.
                        // The q polynomial is known not to have zeros in the domain.
                        // No scaling required because p is already 2**96 too large.
                        r := sdiv(p, q)
                    }
                    // r is in the range (0, 0.125) * 2**96
                    // Finalization, we need to:
                    // * multiply by the scale factor s = 5.549…
                    // * add ln(2**96 / 10**18)
                    // * add k * ln(2)
                    // * multiply by 10**18 / 2**96 = 5**18 >> 78
                    // mul s * 5e18 * 2**96, base is now 5**18 * 2**192
                    r *= 1677202110996718588342820967067443963516166;
                    // add ln(2) * k * 5e18 * 2**192
                    r += 16597577552685614221487285958193947469193820559219878177908093499208371 * k;
                    // add ln(2**96 / 10**18) * 5e18 * 2**192
                    r += 600920179829731861736702779321621459595472258049074101567377883020018308;
                    // base conversion: mul 2**18 / 2**192
                    r >>= 174;
                }
            }
            /*//////////////////////////////////////////////////////////////
                            LOW LEVEL FIXED POINT OPERATIONS
            //////////////////////////////////////////////////////////////*/
            function mulDivDown(
                uint256 x,
                uint256 y,
                uint256 denominator
            ) internal pure returns (uint256 z) {
                assembly {
                    // Store x * y in z for now.
                    z := mul(x, y)
                    // Equivalent to require(denominator != 0 && (x == 0 || (x * y) / x == y))
                    if iszero(and(iszero(iszero(denominator)), or(iszero(x), eq(div(z, x), y)))) {
                        revert(0, 0)
                    }
                    // Divide z by the denominator.
                    z := div(z, denominator)
                }
            }
            function mulDivUp(
                uint256 x,
                uint256 y,
                uint256 denominator
            ) internal pure returns (uint256 z) {
                assembly {
                    // Store x * y in z for now.
                    z := mul(x, y)
                    // Equivalent to require(denominator != 0 && (x == 0 || (x * y) / x == y))
                    if iszero(and(iszero(iszero(denominator)), or(iszero(x), eq(div(z, x), y)))) {
                        revert(0, 0)
                    }
                    // First, divide z - 1 by the denominator and add 1.
                    // We allow z - 1 to underflow if z is 0, because we multiply the
                    // end result by 0 if z is zero, ensuring we return 0 if z is zero.
                    z := mul(iszero(iszero(z)), add(div(sub(z, 1), denominator), 1))
                }
            }
            function rpow(
                uint256 x,
                uint256 n,
                uint256 scalar
            ) internal pure returns (uint256 z) {
                assembly {
                    switch x
                    case 0 {
                        switch n
                        case 0 {
                            // 0 ** 0 = 1
                            z := scalar
                        }
                        default {
                            // 0 ** n = 0
                            z := 0
                        }
                    }
                    default {
                        switch mod(n, 2)
                        case 0 {
                            // If n is even, store scalar in z for now.
                            z := scalar
                        }
                        default {
                            // If n is odd, store x in z for now.
                            z := x
                        }
                        // Shifting right by 1 is like dividing by 2.
                        let half := shr(1, scalar)
                        for {
                            // Shift n right by 1 before looping to halve it.
                            n := shr(1, n)
                        } n {
                            // Shift n right by 1 each iteration to halve it.
                            n := shr(1, n)
                        } {
                            // Revert immediately if x ** 2 would overflow.
                            // Equivalent to iszero(eq(div(xx, x), x)) here.
                            if shr(128, x) {
                                revert(0, 0)
                            }
                            // Store x squared.
                            let xx := mul(x, x)
                            // Round to the nearest number.
                            let xxRound := add(xx, half)
                            // Revert if xx + half overflowed.
                            if lt(xxRound, xx) {
                                revert(0, 0)
                            }
                            // Set x to scaled xxRound.
                            x := div(xxRound, scalar)
                            // If n is even:
                            if mod(n, 2) {
                                // Compute z * x.
                                let zx := mul(z, x)
                                // If z * x overflowed:
                                if iszero(eq(div(zx, x), z)) {
                                    // Revert if x is non-zero.
                                    if iszero(iszero(x)) {
                                        revert(0, 0)
                                    }
                                }
                                // Round to the nearest number.
                                let zxRound := add(zx, half)
                                // Revert if zx + half overflowed.
                                if lt(zxRound, zx) {
                                    revert(0, 0)
                                }
                                // Return properly scaled zxRound.
                                z := div(zxRound, scalar)
                            }
                        }
                    }
                }
            }
            /*//////////////////////////////////////////////////////////////
                                GENERAL NUMBER UTILITIES
            //////////////////////////////////////////////////////////////*/
            function sqrt(uint256 x) internal pure returns (uint256 z) {
                assembly {
                    let y := x // We start y at x, which will help us make our initial estimate.
                    z := 181 // The "correct" value is 1, but this saves a multiplication later.
                    // This segment is to get a reasonable initial estimate for the Babylonian method. With a bad
                    // start, the correct # of bits increases ~linearly each iteration instead of ~quadratically.
                    // We check y >= 2^(k + 8) but shift right by k bits
                    // each branch to ensure that if x >= 256, then y >= 256.
                    if iszero(lt(y, 0x10000000000000000000000000000000000)) {
                        y := shr(128, y)
                        z := shl(64, z)
                    }
                    if iszero(lt(y, 0x1000000000000000000)) {
                        y := shr(64, y)
                        z := shl(32, z)
                    }
                    if iszero(lt(y, 0x10000000000)) {
                        y := shr(32, y)
                        z := shl(16, z)
                    }
                    if iszero(lt(y, 0x1000000)) {
                        y := shr(16, y)
                        z := shl(8, z)
                    }
                    // Goal was to get z*z*y within a small factor of x. More iterations could
                    // get y in a tighter range. Currently, we will have y in [256, 256*2^16).
                    // We ensured y >= 256 so that the relative difference between y and y+1 is small.
                    // That's not possible if x < 256 but we can just verify those cases exhaustively.
                    // Now, z*z*y <= x < z*z*(y+1), and y <= 2^(16+8), and either y >= 256, or x < 256.
                    // Correctness can be checked exhaustively for x < 256, so we assume y >= 256.
                    // Then z*sqrt(y) is within sqrt(257)/sqrt(256) of sqrt(x), or about 20bps.
                    // For s in the range [1/256, 256], the estimate f(s) = (181/1024) * (s+1) is in the range
                    // (1/2.84 * sqrt(s), 2.84 * sqrt(s)), with largest error when s = 1 and when s = 256 or 1/256.
                    // Since y is in [256, 256*2^16), let a = y/65536, so that a is in [1/256, 256). Then we can estimate
                    // sqrt(y) using sqrt(65536) * 181/1024 * (a + 1) = 181/4 * (y + 65536)/65536 = 181 * (y + 65536)/2^18.
                    // There is no overflow risk here since y < 2^136 after the first branch above.
                    z := shr(18, mul(z, add(y, 65536))) // A mul() is saved from starting z at 181.
                    // Given the worst case multiplicative error of 2.84 above, 7 iterations should be enough.
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    // If x+1 is a perfect square, the Babylonian method cycles between
                    // floor(sqrt(x)) and ceil(sqrt(x)). This statement ensures we return floor.
                    // See: https://en.wikipedia.org/wiki/Integer_square_root#Using_only_integer_division
                    // Since the ceil is rare, we save gas on the assignment and repeat division in the rare case.
                    // If you don't care whether the floor or ceil square root is returned, you can remove this statement.
                    z := sub(z, lt(div(x, z), z))
                }
            }
            function log2(uint256 x) internal pure returns (uint256 r) {
                require(x > 0, "UNDEFINED");
                assembly {
                    r := shl(7, lt(0xffffffffffffffffffffffffffffffff, x))
                    r := or(r, shl(6, lt(0xffffffffffffffff, shr(r, x))))
                    r := or(r, shl(5, lt(0xffffffff, shr(r, x))))
                    r := or(r, shl(4, lt(0xffff, shr(r, x))))
                    r := or(r, shl(3, lt(0xff, shr(r, x))))
                    r := or(r, shl(2, lt(0xf, shr(r, x))))
                    r := or(r, shl(1, lt(0x3, shr(r, x))))
                    r := or(r, lt(0x1, shr(r, x)))
                }
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
        pragma solidity ^0.8.0;
        import "../proxy/utils/Initializable.sol";
        /**
         * @dev Provides information about the current execution context, including the
         * sender of the transaction and its data. While these are generally available
         * via msg.sender and msg.data, they should not be accessed in such a direct
         * manner, since when dealing with meta-transactions the account sending and
         * paying for execution may not be the actual sender (as far as an application
         * is concerned).
         *
         * This contract is only required for intermediate, library-like contracts.
         */
        abstract contract ContextUpgradeable is Initializable {
            function __Context_init() internal onlyInitializing {
            }
            function __Context_init_unchained() internal onlyInitializing {
            }
            function _msgSender() internal view virtual returns (address) {
                return msg.sender;
            }
            function _msgData() internal view virtual returns (bytes calldata) {
                return msg.data;
            }
            /**
             * @dev This empty reserved space is put in place to allow future versions to add new
             * variables without shifting down storage in the inheritance chain.
             * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
             */
            uint256[50] private __gap;
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)
        pragma solidity ^0.8.2;
        import "../../utils/AddressUpgradeable.sol";
        /**
         * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
         * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
         * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
         * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
         *
         * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
         * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
         * case an upgrade adds a module that needs to be initialized.
         *
         * For example:
         *
         * [.hljs-theme-light.nopadding]
         * ```solidity
         * contract MyToken is ERC20Upgradeable {
         *     function initialize() initializer public {
         *         __ERC20_init("MyToken", "MTK");
         *     }
         * }
         *
         * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
         *     function initializeV2() reinitializer(2) public {
         *         __ERC20Permit_init("MyToken");
         *     }
         * }
         * ```
         *
         * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
         * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
         *
         * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
         * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
         *
         * [CAUTION]
         * ====
         * Avoid leaving a contract uninitialized.
         *
         * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
         * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
         * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
         *
         * [.hljs-theme-light.nopadding]
         * ```
         * /// @custom:oz-upgrades-unsafe-allow constructor
         * constructor() {
         *     _disableInitializers();
         * }
         * ```
         * ====
         */
        abstract contract Initializable {
            /**
             * @dev Indicates that the contract has been initialized.
             * @custom:oz-retyped-from bool
             */
            uint8 private _initialized;
            /**
             * @dev Indicates that the contract is in the process of being initialized.
             */
            bool private _initializing;
            /**
             * @dev Triggered when the contract has been initialized or reinitialized.
             */
            event Initialized(uint8 version);
            /**
             * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
             * `onlyInitializing` functions can be used to initialize parent contracts.
             *
             * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
             * constructor.
             *
             * Emits an {Initialized} event.
             */
            modifier initializer() {
                bool isTopLevelCall = !_initializing;
                require(
                    (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
                    "Initializable: contract is already initialized"
                );
                _initialized = 1;
                if (isTopLevelCall) {
                    _initializing = true;
                }
                _;
                if (isTopLevelCall) {
                    _initializing = false;
                    emit Initialized(1);
                }
            }
            /**
             * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
             * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
             * used to initialize parent contracts.
             *
             * A reinitializer may be used after the original initialization step. This is essential to configure modules that
             * are added through upgrades and that require initialization.
             *
             * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
             * cannot be nested. If one is invoked in the context of another, execution will revert.
             *
             * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
             * a contract, executing them in the right order is up to the developer or operator.
             *
             * WARNING: setting the version to 255 will prevent any future reinitialization.
             *
             * Emits an {Initialized} event.
             */
            modifier reinitializer(uint8 version) {
                require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
                _initialized = version;
                _initializing = true;
                _;
                _initializing = false;
                emit Initialized(version);
            }
            /**
             * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
             * {initializer} and {reinitializer} modifiers, directly or indirectly.
             */
            modifier onlyInitializing() {
                require(_initializing, "Initializable: contract is not initializing");
                _;
            }
            /**
             * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
             * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
             * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
             * through proxies.
             *
             * Emits an {Initialized} event the first time it is successfully executed.
             */
            function _disableInitializers() internal virtual {
                require(!_initializing, "Initializable: contract is initializing");
                if (_initialized != type(uint8).max) {
                    _initialized = type(uint8).max;
                    emit Initialized(type(uint8).max);
                }
            }
            /**
             * @dev Returns the highest version that has been initialized. See {reinitializer}.
             */
            function _getInitializedVersion() internal view returns (uint8) {
                return _initialized;
            }
            /**
             * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
             */
            function _isInitializing() internal view returns (bool) {
                return _initializing;
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)
        pragma solidity ^0.8.0;
        import "../utils/Context.sol";
        /**
         * @dev Contract module which provides a basic access control mechanism, where
         * there is an account (an owner) that can be granted exclusive access to
         * specific functions.
         *
         * By default, the owner account will be the one that deploys the contract. This
         * can later be changed with {transferOwnership}.
         *
         * This module is used through inheritance. It will make available the modifier
         * `onlyOwner`, which can be applied to your functions to restrict their use to
         * the owner.
         */
        abstract contract Ownable is Context {
            address private _owner;
            event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
            /**
             * @dev Initializes the contract setting the deployer as the initial owner.
             */
            constructor() {
                _transferOwnership(_msgSender());
            }
            /**
             * @dev Throws if called by any account other than the owner.
             */
            modifier onlyOwner() {
                _checkOwner();
                _;
            }
            /**
             * @dev Returns the address of the current owner.
             */
            function owner() public view virtual returns (address) {
                return _owner;
            }
            /**
             * @dev Throws if the sender is not the owner.
             */
            function _checkOwner() internal view virtual {
                require(owner() == _msgSender(), "Ownable: caller is not the owner");
            }
            /**
             * @dev Leaves the contract without owner. It will not be possible to call
             * `onlyOwner` functions. Can only be called by the current owner.
             *
             * NOTE: Renouncing ownership will leave the contract without an owner,
             * thereby disabling any functionality that is only available to the owner.
             */
            function renounceOwnership() public virtual onlyOwner {
                _transferOwnership(address(0));
            }
            /**
             * @dev Transfers ownership of the contract to a new account (`newOwner`).
             * Can only be called by the current owner.
             */
            function transferOwnership(address newOwner) public virtual onlyOwner {
                require(newOwner != address(0), "Ownable: new owner is the zero address");
                _transferOwnership(newOwner);
            }
            /**
             * @dev Transfers ownership of the contract to a new account (`newOwner`).
             * Internal function without access restriction.
             */
            function _transferOwnership(address newOwner) internal virtual {
                address oldOwner = _owner;
                _owner = newOwner;
                emit OwnershipTransferred(oldOwner, newOwner);
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        /**
         * @title Bytes32
         * @notice Bytes32 is a library for manipulating byte32.
         */
        library Bytes32 {
            /**
             * @notice Splits bytes32 to high and low parts.
             *
             * @param _bytes Bytes32 to split.
             *
             * @return High part of bytes32.
             * @return Low part of bytes32.
             */
            function split(bytes32 _bytes) internal pure returns (bytes32, bytes32) {
                bytes16 high = bytes16(_bytes);
                bytes16 low = bytes16(uint128(uint256(_bytes)));
                return (fromBytes16(high), fromBytes16(low));
            }
            /**
             * @notice Converts bytes16 to bytes32.
             *
             * @param _bytes Bytes to constrcut to bytes32.
             *
             * @return Bytes32 constructed from bytes16.
             */
            function fromBytes16(bytes16 _bytes) internal pure returns (bytes32) {
                return bytes32(uint256(uint128(_bytes)));
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Predeploys } from "../libraries/Predeploys.sol";
        import { Semver } from "../universal/Semver.sol";
        import { StandardBridge } from "../universal/StandardBridge.sol";
        /**
         * @custom:proxied
         * @custom:predeploy 0x4200000000000000000000000000000000000009
         * @title L2StandardBridge
         * @notice The L2StandardBridge is responsible for transfering ETH and ERC20 tokens between L1 and
         *         L2. In the case that an ERC20 token is native to L2, it will be escrowed within this
         *         contract. If the ERC20 token is native to L1, it will be burnt.
         *         NOTE: this contract is not intended to support all variations of ERC20 tokens. Examples
         *         of some token types that may not be properly supported by this contract include, but are
         *         not limited to: tokens with transfer fees, rebasing tokens, and tokens with blocklists.
         */
        contract L2StandardBridge is StandardBridge, Semver {
            /**
             * @custom:semver 1.0.0
             *
             * @param _otherBridge Address of the L1StandardBridge.
             */
            constructor(address payable _otherBridge)
                Semver(1, 0, 0)
                StandardBridge(payable(Predeploys.L2_CROSS_DOMAIN_MESSENGER), _otherBridge)
            {}
            /**
             * @notice Allows EOAs to bridge ETH by sending directly to the bridge.
             */
            receive() external payable override onlyEOA {
                _initiateBridgeETH(
                    msg.sender,
                    msg.sender,
                    msg.value,
                    RECEIVE_DEFAULT_GAS_LIMIT,
                    bytes("")
                );
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Predeploys } from "../libraries/Predeploys.sol";
        import { L2StandardBridge } from "../L2/L2StandardBridge.sol";
        /**
         * @title FeeVault
         * @notice The FeeVault contract contains the basic logic for the various different vault contracts
         *         used to hold fee revenue generated by the L2 system.
         */
        abstract contract FeeVault {
            /**
             * @notice Emits each time that a withdrawal occurs.
             *
             * @param value Amount that was withdrawn (in wei).
             * @param to    Address that the funds were sent to.
             * @param from  Address that triggered the withdrawal.
             */
            event Withdrawal(uint256 value, address to, address from);
            /**
             * @notice Minimum balance before a withdrawal can be triggered.
             */
            uint256 public immutable MIN_WITHDRAWAL_AMOUNT;
            /**
             * @notice Wallet that will receive the fees on L1.
             */
            address public immutable RECIPIENT;
            /**
             * @notice The minimum gas limit for the FeeVault withdrawal transaction.
             */
            uint32 internal constant WITHDRAWAL_MIN_GAS = 35_000;
            /**
             * @notice Total amount of wei processed by the contract.
             */
            uint256 public totalProcessed;
            /**
             * @param _recipient           Wallet that will receive the fees on L1.
             * @param _minWithdrawalAmount Minimum balance before a withdrawal can be triggered.
             */
            constructor(address _recipient, uint256 _minWithdrawalAmount) {
                MIN_WITHDRAWAL_AMOUNT = _minWithdrawalAmount;
                RECIPIENT = _recipient;
            }
            /**
             * @notice Allow the contract to receive ETH.
             */
            receive() external payable {}
            /**
             * @notice Triggers a withdrawal of funds to the L1 fee wallet.
             */
            function withdraw() external virtual {
                require(
                    address(this).balance >= MIN_WITHDRAWAL_AMOUNT,
                    "FeeVault: withdrawal amount must be greater than minimum withdrawal amount"
                );
                uint256 value = address(this).balance;
                totalProcessed += value;
                emit Withdrawal(value, RECIPIENT, msg.sender);
                L2StandardBridge(payable(Predeploys.L2_STANDARD_BRIDGE)).bridgeETHTo{ value: value }(
                    RECIPIENT,
                    WITHDRAWAL_MIN_GAS,
                    bytes("")
                );
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
        pragma solidity ^0.8.1;
        /**
         * @dev Collection of functions related to the address type
         */
        library AddressUpgradeable {
            /**
             * @dev Returns true if `account` is a contract.
             *
             * [IMPORTANT]
             * ====
             * It is unsafe to assume that an address for which this function returns
             * false is an externally-owned account (EOA) and not a contract.
             *
             * Among others, `isContract` will return false for the following
             * types of addresses:
             *
             *  - an externally-owned account
             *  - a contract in construction
             *  - an address where a contract will be created
             *  - an address where a contract lived, but was destroyed
             *
             * Furthermore, `isContract` will also return true if the target contract within
             * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
             * which only has an effect at the end of a transaction.
             * ====
             *
             * [IMPORTANT]
             * ====
             * You shouldn't rely on `isContract` to protect against flash loan attacks!
             *
             * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
             * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
             * constructor.
             * ====
             */
            function isContract(address account) internal view returns (bool) {
                // This method relies on extcodesize/address.code.length, which returns 0
                // for contracts in construction, since the code is only stored at the end
                // of the constructor execution.
                return account.code.length > 0;
            }
            /**
             * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
             * `recipient`, forwarding all available gas and reverting on errors.
             *
             * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
             * of certain opcodes, possibly making contracts go over the 2300 gas limit
             * imposed by `transfer`, making them unable to receive funds via
             * `transfer`. {sendValue} removes this limitation.
             *
             * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
             *
             * IMPORTANT: because control is transferred to `recipient`, care must be
             * taken to not create reentrancy vulnerabilities. Consider using
             * {ReentrancyGuard} or the
             * https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
             */
            function sendValue(address payable recipient, uint256 amount) internal {
                require(address(this).balance >= amount, "Address: insufficient balance");
                (bool success, ) = recipient.call{value: amount}("");
                require(success, "Address: unable to send value, recipient may have reverted");
            }
            /**
             * @dev Performs a Solidity function call using a low level `call`. A
             * plain `call` is an unsafe replacement for a function call: use this
             * function instead.
             *
             * If `target` reverts with a revert reason, it is bubbled up by this
             * function (like regular Solidity function calls).
             *
             * Returns the raw returned data. To convert to the expected return value,
             * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
             *
             * Requirements:
             *
             * - `target` must be a contract.
             * - calling `target` with `data` must not revert.
             *
             * _Available since v3.1._
             */
            function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                return functionCallWithValue(target, data, 0, "Address: low-level call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
             * `errorMessage` as a fallback revert reason when `target` reverts.
             *
             * _Available since v3.1._
             */
            function functionCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal returns (bytes memory) {
                return functionCallWithValue(target, data, 0, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but also transferring `value` wei to `target`.
             *
             * Requirements:
             *
             * - the calling contract must have an ETH balance of at least `value`.
             * - the called Solidity function must be `payable`.
             *
             * _Available since v3.1._
             */
            function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
            }
            /**
             * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
             * with `errorMessage` as a fallback revert reason when `target` reverts.
             *
             * _Available since v3.1._
             */
            function functionCallWithValue(
                address target,
                bytes memory data,
                uint256 value,
                string memory errorMessage
            ) internal returns (bytes memory) {
                require(address(this).balance >= value, "Address: insufficient balance for call");
                (bool success, bytes memory returndata) = target.call{value: value}(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but performing a static call.
             *
             * _Available since v3.3._
             */
            function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                return functionStaticCall(target, data, "Address: low-level static call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
             * but performing a static call.
             *
             * _Available since v3.3._
             */
            function functionStaticCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal view returns (bytes memory) {
                (bool success, bytes memory returndata) = target.staticcall(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but performing a delegate call.
             *
             * _Available since v3.4._
             */
            function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                return functionDelegateCall(target, data, "Address: low-level delegate call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
             * but performing a delegate call.
             *
             * _Available since v3.4._
             */
            function functionDelegateCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal returns (bytes memory) {
                (bool success, bytes memory returndata) = target.delegatecall(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
             * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
             *
             * _Available since v4.8._
             */
            function verifyCallResultFromTarget(
                address target,
                bool success,
                bytes memory returndata,
                string memory errorMessage
            ) internal view returns (bytes memory) {
                if (success) {
                    if (returndata.length == 0) {
                        // only check isContract if the call was successful and the return data is empty
                        // otherwise we already know that it was a contract
                        require(isContract(target), "Address: call to non-contract");
                    }
                    return returndata;
                } else {
                    _revert(returndata, errorMessage);
                }
            }
            /**
             * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
             * revert reason or using the provided one.
             *
             * _Available since v4.3._
             */
            function verifyCallResult(
                bool success,
                bytes memory returndata,
                string memory errorMessage
            ) internal pure returns (bytes memory) {
                if (success) {
                    return returndata;
                } else {
                    _revert(returndata, errorMessage);
                }
            }
            function _revert(bytes memory returndata, string memory errorMessage) private pure {
                // Look for revert reason and bubble it up if present
                if (returndata.length > 0) {
                    // The easiest way to bubble the revert reason is using memory via assembly
                    /// @solidity memory-safe-assembly
                    assembly {
                        let returndata_size := mload(returndata)
                        revert(add(32, returndata), returndata_size)
                    }
                } else {
                    revert(errorMessage);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
        pragma solidity ^0.8.0;
        /**
         * @dev Provides information about the current execution context, including the
         * sender of the transaction and its data. While these are generally available
         * via msg.sender and msg.data, they should not be accessed in such a direct
         * manner, since when dealing with meta-transactions the account sending and
         * paying for execution may not be the actual sender (as far as an application
         * is concerned).
         *
         * This contract is only required for intermediate, library-like contracts.
         */
        abstract contract Context {
            function _msgSender() internal view virtual returns (address) {
                return msg.sender;
            }
            function _msgData() internal view virtual returns (bytes calldata) {
                return msg.data;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Address } from "@openzeppelin/contracts/utils/Address.sol";
        import { ERC165Checker } from "@openzeppelin/contracts/utils/introspection/ERC165Checker.sol";
        import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
        import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
        import { SafeCall } from "../libraries/SafeCall.sol";
        import { CrossDomainMessenger } from "./CrossDomainMessenger.sol";
        import { IKromaMintableERC20 } from "./IKromaMintableERC20.sol";
        import { KromaMintableERC20 } from "./KromaMintableERC20.sol";
        /**
         * @custom:upgradeable
         * @title StandardBridge
         * @notice StandardBridge is a base contract for the L1 and L2 standard ERC20 bridges. It handles
         *         the core bridging logic, including escrowing tokens that are native to the local chain
         *         and minting/burning tokens that are native to the remote chain.
         */
        abstract contract StandardBridge {
            using SafeERC20 for IERC20;
            /**
             * @notice The L2 gas limit set when eth is depoisited using the receive() function.
             */
            uint32 internal constant RECEIVE_DEFAULT_GAS_LIMIT = 200_000;
            /**
             * @notice Messenger contract on this domain.
             */
            CrossDomainMessenger public immutable MESSENGER;
            /**
             * @notice Corresponding bridge on the other domain.
             */
            StandardBridge public immutable OTHER_BRIDGE;
            /**
             * @notice Mapping that stores deposits for a given pair of local and remote tokens.
             */
            mapping(address => mapping(address => uint256)) public deposits;
            /**
             * @notice Reserve extra slots (to a total of 50) in the storage layout for future upgrades.
             *         A gap size of 49 was chosen here, so that the first slot used in a child contract
             *         would be a multiple of 50.
             */
            uint256[49] private __gap;
            /**
             * @notice Emitted when an ETH bridge is initiated to the other chain.
             *
             * @param from      Address of the sender.
             * @param to        Address of the receiver.
             * @param amount    Amount of ETH sent.
             * @param extraData Extra data sent with the transaction.
             */
            event ETHBridgeInitiated(
                address indexed from,
                address indexed to,
                uint256 amount,
                bytes extraData
            );
            /**
             * @notice Emitted when an ETH bridge is finalized on this chain.
             *
             * @param from      Address of the sender.
             * @param to        Address of the receiver.
             * @param amount    Amount of ETH sent.
             * @param extraData Extra data sent with the transaction.
             */
            event ETHBridgeFinalized(
                address indexed from,
                address indexed to,
                uint256 amount,
                bytes extraData
            );
            /**
             * @notice Emitted when an ERC20 bridge is initiated to the other chain.
             *
             * @param localToken  Address of the ERC20 on this chain.
             * @param remoteToken Address of the ERC20 on the remote chain.
             * @param from        Address of the sender.
             * @param to          Address of the receiver.
             * @param amount      Amount of the ERC20 sent.
             * @param extraData   Extra data sent with the transaction.
             */
            event ERC20BridgeInitiated(
                address indexed localToken,
                address indexed remoteToken,
                address indexed from,
                address to,
                uint256 amount,
                bytes extraData
            );
            /**
             * @notice Emitted when an ERC20 bridge is finalized on this chain.
             *
             * @param localToken  Address of the ERC20 on this chain.
             * @param remoteToken Address of the ERC20 on the remote chain.
             * @param from        Address of the sender.
             * @param to          Address of the receiver.
             * @param amount      Amount of the ERC20 sent.
             * @param extraData   Extra data sent with the transaction.
             */
            event ERC20BridgeFinalized(
                address indexed localToken,
                address indexed remoteToken,
                address indexed from,
                address to,
                uint256 amount,
                bytes extraData
            );
            /**
             * @notice Only allow EOAs to call the functions. Note that this is not safe against contracts
             *         calling code within their constructors, but also doesn't really matter since we're
             *         just trying to prevent users accidentally depositing with smart contract wallets.
             */
            modifier onlyEOA() {
                require(
                    !Address.isContract(msg.sender),
                    "StandardBridge: function can only be called from an EOA"
                );
                _;
            }
            /**
             * @notice Ensures that the caller is a cross-chain message from the other bridge.
             */
            modifier onlyOtherBridge() {
                require(
                    msg.sender == address(MESSENGER) &&
                        MESSENGER.xDomainMessageSender() == address(OTHER_BRIDGE),
                    "StandardBridge: function can only be called from the other bridge"
                );
                _;
            }
            /**
             * @param _messenger   Address of CrossDomainMessenger on this network.
             * @param _otherBridge Address of the other StandardBridge contract.
             */
            constructor(address payable _messenger, address payable _otherBridge) {
                MESSENGER = CrossDomainMessenger(_messenger);
                OTHER_BRIDGE = StandardBridge(_otherBridge);
            }
            /**
             * @notice Allows EOAs to bridge ETH by sending directly to the bridge.
             *         Must be implemented by contracts that inherit.
             */
            receive() external payable virtual;
            /**
             * @notice Sends ETH to the sender's address on the other chain.
             *
             * @param _minGasLimit Minimum amount of gas that the bridge can be relayed with.
             * @param _extraData   Extra data to be sent with the transaction. Note that the recipient will
             *                     not be triggered with this data, but it will be emitted and can be used
             *                     to identify the transaction.
             */
            function bridgeETH(uint32 _minGasLimit, bytes calldata _extraData) public payable onlyEOA {
                _initiateBridgeETH(msg.sender, msg.sender, msg.value, _minGasLimit, _extraData);
            }
            /**
             * @notice Sends ETH to a receiver's address on the other chain. Note that if ETH is sent to a
             *         smart contract and the call fails, the ETH will be temporarily locked in the
             *         StandardBridge on the other chain until the call is replayed. If the call cannot be
             *         replayed with any amount of gas (call always reverts), then the ETH will be
             *         permanently locked in the StandardBridge on the other chain. ETH will also
             *         be locked if the receiver is the other bridge, because finalizeBridgeETH will revert
             *         in that case.
             *
             * @param _to          Address of the receiver.
             * @param _minGasLimit Minimum amount of gas that the bridge can be relayed with.
             * @param _extraData   Extra data to be sent with the transaction. Note that the recipient will
             *                     not be triggered with this data, but it will be emitted and can be used
             *                     to identify the transaction.
             */
            function bridgeETHTo(
                address _to,
                uint32 _minGasLimit,
                bytes calldata _extraData
            ) public payable {
                _initiateBridgeETH(msg.sender, _to, msg.value, _minGasLimit, _extraData);
            }
            /**
             * @notice Sends ERC20 tokens to the sender's address on the other chain. Note that if the
             *         ERC20 token on the other chain does not recognize the local token as the correct
             *         pair token, the ERC20 bridge will fail and the tokens will be returned to sender on
             *         this chain.
             *
             * @param _localToken  Address of the ERC20 on this chain.
             * @param _remoteToken Address of the corresponding token on the remote chain.
             * @param _amount      Amount of local tokens to deposit.
             * @param _minGasLimit Minimum amount of gas that the bridge can be relayed with.
             * @param _extraData   Extra data to be sent with the transaction. Note that the recipient will
             *                     not be triggered with this data, but it will be emitted and can be used
             *                     to identify the transaction.
             */
            function bridgeERC20(
                address _localToken,
                address _remoteToken,
                uint256 _amount,
                uint32 _minGasLimit,
                bytes calldata _extraData
            ) public onlyEOA {
                _initiateBridgeERC20(
                    _localToken,
                    _remoteToken,
                    msg.sender,
                    msg.sender,
                    _amount,
                    _minGasLimit,
                    _extraData
                );
            }
            /**
             * @notice Sends ERC20 tokens to a receiver's address on the other chain. Note that if the
             *         ERC20 token on the other chain does not recognize the local token as the correct
             *         pair token, the ERC20 bridge will fail and the tokens will be returned to sender on
             *         this chain.
             *
             * @param _localToken  Address of the ERC20 on this chain.
             * @param _remoteToken Address of the corresponding token on the remote chain.
             * @param _to          Address of the receiver.
             * @param _amount      Amount of local tokens to deposit.
             * @param _minGasLimit Minimum amount of gas that the bridge can be relayed with.
             * @param _extraData   Extra data to be sent with the transaction. Note that the recipient will
             *                     not be triggered with this data, but it will be emitted and can be used
             *                     to identify the transaction.
             */
            function bridgeERC20To(
                address _localToken,
                address _remoteToken,
                address _to,
                uint256 _amount,
                uint32 _minGasLimit,
                bytes calldata _extraData
            ) public {
                _initiateBridgeERC20(
                    _localToken,
                    _remoteToken,
                    msg.sender,
                    _to,
                    _amount,
                    _minGasLimit,
                    _extraData
                );
            }
            /**
             * @notice Finalizes an ETH bridge on this chain. Can only be triggered by the other
             *         StandardBridge contract on the remote chain.
             *
             * @param _from      Address of the sender.
             * @param _to        Address of the receiver.
             * @param _amount    Amount of ETH being bridged.
             * @param _extraData Extra data to be sent with the transaction. Note that the recipient will
             *                   not be triggered with this data, but it will be emitted and can be used
             *                   to identify the transaction.
             */
            function finalizeBridgeETH(
                address _from,
                address _to,
                uint256 _amount,
                bytes calldata _extraData
            ) public payable onlyOtherBridge {
                require(msg.value == _amount, "StandardBridge: amount sent does not match amount required");
                require(_to != address(this), "StandardBridge: cannot send to self");
                require(_to != address(MESSENGER), "StandardBridge: cannot send to messenger");
                emit ETHBridgeFinalized(_from, _to, _amount, _extraData);
                bool success = SafeCall.call(_to, gasleft(), _amount, hex"");
                require(success, "StandardBridge: ETH transfer failed");
            }
            /**
             * @notice Finalizes an ERC20 bridge on this chain. Can only be triggered by the other
             *         StandardBridge contract on the remote chain.
             *
             * @param _localToken  Address of the ERC20 on this chain.
             * @param _remoteToken Address of the corresponding token on the remote chain.
             * @param _from        Address of the sender.
             * @param _to          Address of the receiver.
             * @param _amount      Amount of the ERC20 being bridged.
             * @param _extraData   Extra data to be sent with the transaction. Note that the recipient will
             *                     not be triggered with this data, but it will be emitted and can be used
             *                     to identify the transaction.
             */
            function finalizeBridgeERC20(
                address _localToken,
                address _remoteToken,
                address _from,
                address _to,
                uint256 _amount,
                bytes calldata _extraData
            ) public onlyOtherBridge {
                if (_isKromaMintableERC20(_localToken)) {
                    require(
                        _isCorrectTokenPair(_localToken, _remoteToken),
                        "StandardBridge: wrong remote token for Kroma Mintable ERC20 local token"
                    );
                    KromaMintableERC20(_localToken).mint(_to, _amount);
                } else {
                    deposits[_localToken][_remoteToken] = deposits[_localToken][_remoteToken] - _amount;
                    IERC20(_localToken).safeTransfer(_to, _amount);
                }
                emit ERC20BridgeFinalized(_localToken, _remoteToken, _from, _to, _amount, _extraData);
            }
            /**
             * @notice Initiates a bridge of ETH through the CrossDomainMessenger.
             *
             * @param _from        Address of the sender.
             * @param _to          Address of the receiver.
             * @param _amount      Amount of ETH being bridged.
             * @param _minGasLimit Minimum amount of gas that the bridge can be relayed with.
             * @param _extraData   Extra data to be sent with the transaction. Note that the recipient will
             *                     not be triggered with this data, but it will be emitted and can be used
             *                     to identify the transaction.
             */
            function _initiateBridgeETH(
                address _from,
                address _to,
                uint256 _amount,
                uint32 _minGasLimit,
                bytes memory _extraData
            ) internal {
                require(
                    msg.value == _amount,
                    "StandardBridge: bridging ETH must include sufficient ETH value"
                );
                emit ETHBridgeInitiated(_from, _to, _amount, _extraData);
                MESSENGER.sendMessage{ value: _amount }(
                    address(OTHER_BRIDGE),
                    abi.encodeWithSelector(
                        this.finalizeBridgeETH.selector,
                        _from,
                        _to,
                        _amount,
                        _extraData
                    ),
                    _minGasLimit
                );
            }
            /**
             * @notice Sends ERC20 tokens to a receiver's address on the other chain.
             *
             * @param _localToken  Address of the ERC20 on this chain.
             * @param _remoteToken Address of the corresponding token on the remote chain.
             * @param _to          Address of the receiver.
             * @param _amount      Amount of local tokens to deposit.
             * @param _minGasLimit Minimum amount of gas that the bridge can be relayed with.
             * @param _extraData   Extra data to be sent with the transaction. Note that the recipient will
             *                     not be triggered with this data, but it will be emitted and can be used
             *                     to identify the transaction.
             */
            function _initiateBridgeERC20(
                address _localToken,
                address _remoteToken,
                address _from,
                address _to,
                uint256 _amount,
                uint32 _minGasLimit,
                bytes memory _extraData
            ) internal {
                if (_isKromaMintableERC20(_localToken)) {
                    require(
                        _isCorrectTokenPair(_localToken, _remoteToken),
                        "StandardBridge: wrong remote token for Kroma Mintable ERC20 local token"
                    );
                    KromaMintableERC20(_localToken).burn(_from, _amount);
                } else {
                    IERC20(_localToken).safeTransferFrom(_from, address(this), _amount);
                    deposits[_localToken][_remoteToken] = deposits[_localToken][_remoteToken] + _amount;
                }
                emit ERC20BridgeInitiated(_localToken, _remoteToken, _from, _to, _amount, _extraData);
                MESSENGER.sendMessage(
                    address(OTHER_BRIDGE),
                    abi.encodeWithSelector(
                        this.finalizeBridgeERC20.selector,
                        // Because this call will be executed on the remote chain, we reverse the order of
                        // the remote and local token addresses relative to their order in the
                        // finalizeBridgeERC20 function.
                        _remoteToken,
                        _localToken,
                        _from,
                        _to,
                        _amount,
                        _extraData
                    ),
                    _minGasLimit
                );
            }
            /**
             * @notice Checks if a given address is a KromaMintableERC20. Not perfect, but good enough.
             *         Just the way we like it.
             *
             * @param _token Address of the token to check.
             *
             * @return True if the token is a KromaMintableERC20.
             */
            function _isKromaMintableERC20(address _token) internal view returns (bool) {
                return ERC165Checker.supportsInterface(_token, type(IKromaMintableERC20).interfaceId);
            }
            /**
             * @notice Checks if the "other token" is the correct pair token for the KromaMintableERC20.
             *
             * @param _mintableToken KromaMintableERC20 to check against.
             * @param _otherToken    Pair token to check.
             *
             * @return True if the other token is the correct pair token for the KromaMintableERC20.
             */
            function _isCorrectTokenPair(address _mintableToken, address _otherToken)
                internal
                view
                returns (bool)
            {
                return _otherToken == KromaMintableERC20(_mintableToken).REMOTE_TOKEN();
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/introspection/ERC165Checker.sol)
        pragma solidity ^0.8.0;
        import "./IERC165.sol";
        /**
         * @dev Library used to query support of an interface declared via {IERC165}.
         *
         * Note that these functions return the actual result of the query: they do not
         * `revert` if an interface is not supported. It is up to the caller to decide
         * what to do in these cases.
         */
        library ERC165Checker {
            // As per the EIP-165 spec, no interface should ever match 0xffffffff
            bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;
            /**
             * @dev Returns true if `account` supports the {IERC165} interface.
             */
            function supportsERC165(address account) internal view returns (bool) {
                // Any contract that implements ERC165 must explicitly indicate support of
                // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
                return
                    supportsERC165InterfaceUnchecked(account, type(IERC165).interfaceId) &&
                    !supportsERC165InterfaceUnchecked(account, _INTERFACE_ID_INVALID);
            }
            /**
             * @dev Returns true if `account` supports the interface defined by
             * `interfaceId`. Support for {IERC165} itself is queried automatically.
             *
             * See {IERC165-supportsInterface}.
             */
            function supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) {
                // query support of both ERC165 as per the spec and support of _interfaceId
                return supportsERC165(account) && supportsERC165InterfaceUnchecked(account, interfaceId);
            }
            /**
             * @dev Returns a boolean array where each value corresponds to the
             * interfaces passed in and whether they're supported or not. This allows
             * you to batch check interfaces for a contract where your expectation
             * is that some interfaces may not be supported.
             *
             * See {IERC165-supportsInterface}.
             *
             * _Available since v3.4._
             */
            function getSupportedInterfaces(
                address account,
                bytes4[] memory interfaceIds
            ) internal view returns (bool[] memory) {
                // an array of booleans corresponding to interfaceIds and whether they're supported or not
                bool[] memory interfaceIdsSupported = new bool[](interfaceIds.length);
                // query support of ERC165 itself
                if (supportsERC165(account)) {
                    // query support of each interface in interfaceIds
                    for (uint256 i = 0; i < interfaceIds.length; i++) {
                        interfaceIdsSupported[i] = supportsERC165InterfaceUnchecked(account, interfaceIds[i]);
                    }
                }
                return interfaceIdsSupported;
            }
            /**
             * @dev Returns true if `account` supports all the interfaces defined in
             * `interfaceIds`. Support for {IERC165} itself is queried automatically.
             *
             * Batch-querying can lead to gas savings by skipping repeated checks for
             * {IERC165} support.
             *
             * See {IERC165-supportsInterface}.
             */
            function supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) {
                // query support of ERC165 itself
                if (!supportsERC165(account)) {
                    return false;
                }
                // query support of each interface in interfaceIds
                for (uint256 i = 0; i < interfaceIds.length; i++) {
                    if (!supportsERC165InterfaceUnchecked(account, interfaceIds[i])) {
                        return false;
                    }
                }
                // all interfaces supported
                return true;
            }
            /**
             * @notice Query if a contract implements an interface, does not check ERC165 support
             * @param account The address of the contract to query for support of an interface
             * @param interfaceId The interface identifier, as specified in ERC-165
             * @return true if the contract at account indicates support of the interface with
             * identifier interfaceId, false otherwise
             * @dev Assumes that account contains a contract that supports ERC165, otherwise
             * the behavior of this method is undefined. This precondition can be checked
             * with {supportsERC165}.
             *
             * Some precompiled contracts will falsely indicate support for a given interface, so caution
             * should be exercised when using this function.
             *
             * Interface identification is specified in ERC-165.
             */
            function supportsERC165InterfaceUnchecked(address account, bytes4 interfaceId) internal view returns (bool) {
                // prepare call
                bytes memory encodedParams = abi.encodeWithSelector(IERC165.supportsInterface.selector, interfaceId);
                // perform static call
                bool success;
                uint256 returnSize;
                uint256 returnValue;
                assembly {
                    success := staticcall(30000, account, add(encodedParams, 0x20), mload(encodedParams), 0x00, 0x20)
                    returnSize := returndatasize()
                    returnValue := mload(0x00)
                }
                return success && returnSize >= 0x20 && returnValue > 0;
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
        pragma solidity ^0.8.0;
        /**
         * @dev Interface of the ERC20 standard as defined in the EIP.
         */
        interface IERC20 {
            /**
             * @dev Emitted when `value` tokens are moved from one account (`from`) to
             * another (`to`).
             *
             * Note that `value` may be zero.
             */
            event Transfer(address indexed from, address indexed to, uint256 value);
            /**
             * @dev Emitted when the allowance of a `spender` for an `owner` is set by
             * a call to {approve}. `value` is the new allowance.
             */
            event Approval(address indexed owner, address indexed spender, uint256 value);
            /**
             * @dev Returns the amount of tokens in existence.
             */
            function totalSupply() external view returns (uint256);
            /**
             * @dev Returns the amount of tokens owned by `account`.
             */
            function balanceOf(address account) external view returns (uint256);
            /**
             * @dev Moves `amount` tokens from the caller's account to `to`.
             *
             * Returns a boolean value indicating whether the operation succeeded.
             *
             * Emits a {Transfer} event.
             */
            function transfer(address to, uint256 amount) external returns (bool);
            /**
             * @dev Returns the remaining number of tokens that `spender` will be
             * allowed to spend on behalf of `owner` through {transferFrom}. This is
             * zero by default.
             *
             * This value changes when {approve} or {transferFrom} are called.
             */
            function allowance(address owner, address spender) external view returns (uint256);
            /**
             * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
             *
             * Returns a boolean value indicating whether the operation succeeded.
             *
             * IMPORTANT: Beware that changing an allowance with this method brings the risk
             * that someone may use both the old and the new allowance by unfortunate
             * transaction ordering. One possible solution to mitigate this race
             * condition is to first reduce the spender's allowance to 0 and set the
             * desired value afterwards:
             * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
             *
             * Emits an {Approval} event.
             */
            function approve(address spender, uint256 amount) external returns (bool);
            /**
             * @dev Moves `amount` tokens from `from` to `to` using the
             * allowance mechanism. `amount` is then deducted from the caller's
             * allowance.
             *
             * Returns a boolean value indicating whether the operation succeeded.
             *
             * Emits a {Transfer} event.
             */
            function transferFrom(address from, address to, uint256 amount) external returns (bool);
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.3) (token/ERC20/utils/SafeERC20.sol)
        pragma solidity ^0.8.0;
        import "../IERC20.sol";
        import "../extensions/IERC20Permit.sol";
        import "../../../utils/Address.sol";
        /**
         * @title SafeERC20
         * @dev Wrappers around ERC20 operations that throw on failure (when the token
         * contract returns false). Tokens that return no value (and instead revert or
         * throw on failure) are also supported, non-reverting calls are assumed to be
         * successful.
         * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
         * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
         */
        library SafeERC20 {
            using Address for address;
            /**
             * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
             * non-reverting calls are assumed to be successful.
             */
            function safeTransfer(IERC20 token, address to, uint256 value) internal {
                _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
            }
            /**
             * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
             * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
             */
            function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
                _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
            }
            /**
             * @dev Deprecated. This function has issues similar to the ones found in
             * {IERC20-approve}, and its usage is discouraged.
             *
             * Whenever possible, use {safeIncreaseAllowance} and
             * {safeDecreaseAllowance} instead.
             */
            function safeApprove(IERC20 token, address spender, uint256 value) internal {
                // safeApprove should only be called when setting an initial allowance,
                // or when resetting it to zero. To increase and decrease it, use
                // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
                require(
                    (value == 0) || (token.allowance(address(this), spender) == 0),
                    "SafeERC20: approve from non-zero to non-zero allowance"
                );
                _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
            }
            /**
             * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
             * non-reverting calls are assumed to be successful.
             */
            function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                uint256 oldAllowance = token.allowance(address(this), spender);
                _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
            }
            /**
             * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
             * non-reverting calls are assumed to be successful.
             */
            function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                unchecked {
                    uint256 oldAllowance = token.allowance(address(this), spender);
                    require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
                    _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
                }
            }
            /**
             * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
             * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
             * to be set to zero before setting it to a non-zero value, such as USDT.
             */
            function forceApprove(IERC20 token, address spender, uint256 value) internal {
                bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);
                if (!_callOptionalReturnBool(token, approvalCall)) {
                    _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
                    _callOptionalReturn(token, approvalCall);
                }
            }
            /**
             * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
             * Revert on invalid signature.
             */
            function safePermit(
                IERC20Permit token,
                address owner,
                address spender,
                uint256 value,
                uint256 deadline,
                uint8 v,
                bytes32 r,
                bytes32 s
            ) internal {
                uint256 nonceBefore = token.nonces(owner);
                token.permit(owner, spender, value, deadline, v, r, s);
                uint256 nonceAfter = token.nonces(owner);
                require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
            }
            /**
             * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
             * on the return value: the return value is optional (but if data is returned, it must not be false).
             * @param token The token targeted by the call.
             * @param data The call data (encoded using abi.encode or one of its variants).
             */
            function _callOptionalReturn(IERC20 token, bytes memory data) private {
                // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
                // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
                // the target address contains contract code and also asserts for success in the low-level call.
                bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
                require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
            }
            /**
             * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
             * on the return value: the return value is optional (but if data is returned, it must not be false).
             * @param token The token targeted by the call.
             * @param data The call data (encoded using abi.encode or one of its variants).
             *
             * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
             */
            function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
                // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
                // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
                // and not revert is the subcall reverts.
                (bool success, bytes memory returndata) = address(token).call(data);
                return
                    success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import {
            PausableUpgradeable
        } from "@openzeppelin/contracts-upgradeable/security/PausableUpgradeable.sol";
        import { Constants } from "../libraries/Constants.sol";
        import { Encoding } from "../libraries/Encoding.sol";
        import { Hashing } from "../libraries/Hashing.sol";
        import { SafeCall } from "../libraries/SafeCall.sol";
        /**
         * @custom:upgradeable
         * @title CrossDomainMessenger
         * @notice CrossDomainMessenger is a base contract that provides the core logic for the L1 and L2
         *         cross-chain messenger contracts. It's designed to be a universal interface that only
         *         needs to be extended slightly to provide low-level message passing functionality on each
         *         chain it's deployed on. Currently only designed for message passing between two paired
         *         chains and does not support one-to-many interactions.
         *
         *         Any changes to this contract MUST result in a semver bump for contracts that inherit it.
         */
        abstract contract CrossDomainMessenger is PausableUpgradeable {
            /**
             * @notice Current message version identifier.
             */
            uint16 public constant MESSAGE_VERSION = 0;
            /**
             * @notice Constant overhead added to the base gas for a message.
             */
            uint64 public constant RELAY_CONSTANT_OVERHEAD = 200_000;
            /**
             * @notice Numerator for dynamic overhead added to the base gas for a message.
             */
            uint64 public constant MIN_GAS_DYNAMIC_OVERHEAD_NUMERATOR = 64;
            /**
             * @notice Denominator for dynamic overhead added to the base gas for a message.
             */
            uint64 public constant MIN_GAS_DYNAMIC_OVERHEAD_DENOMINATOR = 63;
            /**
             * @notice Extra gas added to base gas for each byte of calldata in a message.
             */
            uint64 public constant MIN_GAS_CALLDATA_OVERHEAD = 16;
            /**
             * @notice Gas reserved for performing the external call in `relayMessage`.
             */
            uint64 public constant RELAY_CALL_OVERHEAD = 40_000;
            /**
             * @notice Gas reserved for finalizing the execution of `relayMessage` after the safe call.
             */
            uint64 public constant RELAY_RESERVED_GAS = 40_000;
            /**
             * @notice Gas reserved for the execution between the `hasMinGas` check and the external
             *         call in `relayMessage`.
             */
            uint64 public constant RELAY_GAS_CHECK_BUFFER = 5_000;
            /**
             * @notice Address of the paired CrossDomainMessenger contract on the other chain.
             */
            address public immutable OTHER_MESSENGER;
            /**
             * @notice Mapping of message hashes to boolean receipt values. Note that a message will only
             *         be present in this mapping if it has successfully been relayed on this chain, and
             *         can therefore not be relayed again.
             */
            mapping(bytes32 => bool) public successfulMessages;
            /**
             * @notice Address of the sender of the currently executing message on the other chain. If the
             *         value of this variable is the default value (0x00000000...dead) then no message is
             *         currently being executed. Use the xDomainMessageSender getter which will throw an
             *         error if this is the case.
             */
            address internal xDomainMsgSender;
            /**
             * @notice Nonce for the next message to be sent, without the message version applied. Use the
             *         messageNonce getter which will insert the message version into the nonce to give you
             *         the actual nonce to be used for the message.
             */
            uint240 internal msgNonce;
            /**
             * @notice Mapping of message hashes to a boolean if and only if the message has failed to be
             *         executed at least once. A message will not be present in this mapping if it
             *         successfully executed on the first attempt.
             */
            mapping(bytes32 => bool) public failedMessages;
            /**
             * @notice Reserve extra slots in the storage layout for future upgrades.
             *         A gap size of 45 was chosen here, so that the first slot used in a child contract
             *         would be a multiple of 50.
             */
            uint256[45] private __gap;
            /**
             * @notice Emitted whenever a message is sent to the other chain.
             *
             * @param target       Address of the recipient of the message.
             * @param sender       Address of the sender of the message.
             * @param value        ETH value sent along with the message to the recipient.
             * @param message      Message to trigger the recipient address with.
             * @param messageNonce Unique nonce attached to the message.
             * @param gasLimit     Minimum gas limit that the message can be executed with.
             */
            event SentMessage(
                address indexed target,
                address indexed sender,
                uint256 value,
                bytes message,
                uint256 messageNonce,
                uint256 gasLimit
            );
            /**
             * @notice Emitted whenever a message is successfully relayed on this chain.
             *
             * @param msgHash Hash of the message that was relayed.
             */
            event RelayedMessage(bytes32 indexed msgHash);
            /**
             * @notice Emitted whenever a message fails to be relayed on this chain.
             *
             * @param msgHash Hash of the message that failed to be relayed.
             */
            event FailedRelayedMessage(bytes32 indexed msgHash);
            /**
             * @param _otherMessenger Address of the messenger on the paired chain.
             */
            constructor(address _otherMessenger) {
                OTHER_MESSENGER = _otherMessenger;
            }
            /**
             * @notice Sends a message to some target address on the other chain. Note that if the call
             *         always reverts, then the message will be unrelayable, and any ETH sent will be
             *         permanently locked. The same will occur if the target on the other chain is
             *         considered unsafe (see the _isUnsafeTarget() function).
             *
             * @param _target      Target contract or wallet address.
             * @param _message     Message to trigger the target address with.
             * @param _minGasLimit Minimum gas limit that the message can be executed with.
             */
            function sendMessage(
                address _target,
                bytes calldata _message,
                uint32 _minGasLimit
            ) external payable {
                // Triggers a message to the other messenger. Note that the amount of gas provided to the
                // message is the amount of gas requested by the user PLUS the base gas value. We want to
                // guarantee the property that the call to the target contract will always have at least
                // the minimum gas limit specified by the user.
                _sendMessage(
                    OTHER_MESSENGER,
                    baseGas(_message, _minGasLimit),
                    msg.value,
                    abi.encodeWithSelector(
                        this.relayMessage.selector,
                        messageNonce(),
                        msg.sender,
                        _target,
                        msg.value,
                        _minGasLimit,
                        _message
                    )
                );
                emit SentMessage(_target, msg.sender, msg.value, _message, messageNonce(), _minGasLimit);
                unchecked {
                    ++msgNonce;
                }
            }
            /**
             * @notice Relays a message that was sent by the other CrossDomainMessenger contract. Can only
             *         be executed via cross-chain call from the other messenger OR if the message was
             *         already received once and is currently being replayed.
             *
             * @param _nonce       Nonce of the message being relayed.
             * @param _sender      Address of the user who sent the message.
             * @param _target      Address that the message is targeted at.
             * @param _value       ETH value to send with the message.
             * @param _minGasLimit Minimum amount of gas that the message can be executed with.
             * @param _message     Message to send to the target.
             */
            function relayMessage(
                uint256 _nonce,
                address _sender,
                address _target,
                uint256 _value,
                uint256 _minGasLimit,
                bytes calldata _message
            ) external payable {
                (, uint16 version) = Encoding.decodeVersionedNonce(_nonce);
                require(
                    version < 1,
                    "CrossDomainMessenger: only version 0 messages is supported at this time"
                );
                // We use the v0 message hash as the unique identifier for the message because it commits
                // to the value and minimum gas limit of the message.
                bytes32 versionedHash = Hashing.hashCrossDomainMessageV0(
                    _nonce,
                    _sender,
                    _target,
                    _value,
                    _minGasLimit,
                    _message
                );
                if (_isOtherMessenger()) {
                    // These properties should always hold when the message is first submitted (as
                    // opposed to being replayed).
                    assert(msg.value == _value);
                    assert(!failedMessages[versionedHash]);
                } else {
                    require(
                        msg.value == 0,
                        "CrossDomainMessenger: value must be zero unless message is from a system address"
                    );
                    require(
                        failedMessages[versionedHash],
                        "CrossDomainMessenger: message cannot be replayed"
                    );
                }
                require(
                    _isUnsafeTarget(_target) == false,
                    "CrossDomainMessenger: cannot send message to blocked system address"
                );
                require(
                    successfulMessages[versionedHash] == false,
                    "CrossDomainMessenger: message has already been relayed"
                );
                // If there is not enough gas left to perform the external call and finish the execution,
                // return early and assign the message to the failedMessages mapping.
                // We are asserting that we have enough gas to:
                // 1. Call the target contract (_minGasLimit + RELAY_CALL_OVERHEAD + RELAY_GAS_CHECK_BUFFER)
                //   1.a. The RELAY_CALL_OVERHEAD is included in `hasMinGas`.
                // 2. Finish the execution after the external call (RELAY_RESERVED_GAS).
                //
                // If `xDomainMsgSender` is not the default L2 sender, this function
                // is being re-entered. This marks the message as failed to allow it to be replayed.
                if (
                    !SafeCall.hasMinGas(_minGasLimit, RELAY_RESERVED_GAS + RELAY_GAS_CHECK_BUFFER) ||
                    xDomainMsgSender != Constants.DEFAULT_L2_SENDER
                ) {
                    failedMessages[versionedHash] = true;
                    emit FailedRelayedMessage(versionedHash);
                    // Revert in this case if the transaction was triggered by the estimation address. This
                    // should only be possible during gas estimation or we have bigger problems. Reverting
                    // here will make the behavior of gas estimation change such that the gas limit
                    // computed will be the amount required to relay the message, even if that amount is
                    // greater than the minimum gas limit specified by the user.
                    if (tx.origin == Constants.ESTIMATION_ADDRESS) {
                        revert("CrossDomainMessenger: failed to relay message");
                    }
                    return;
                }
                xDomainMsgSender = _sender;
                bool success = SafeCall.call(_target, gasleft() - RELAY_RESERVED_GAS, _value, _message);
                xDomainMsgSender = Constants.DEFAULT_L2_SENDER;
                if (success) {
                    successfulMessages[versionedHash] = true;
                    emit RelayedMessage(versionedHash);
                } else {
                    failedMessages[versionedHash] = true;
                    emit FailedRelayedMessage(versionedHash);
                    // Revert in this case if the transaction was triggered by the estimation address. This
                    // should only be possible during gas estimation or we have bigger problems. Reverting
                    // here will make the behavior of gas estimation change such that the gas limit
                    // computed will be the amount required to relay the message, even if that amount is
                    // greater than the minimum gas limit specified by the user.
                    if (tx.origin == Constants.ESTIMATION_ADDRESS) {
                        revert("CrossDomainMessenger: failed to relay message");
                    }
                }
            }
            /**
             * @notice Retrieves the address of the contract or wallet that initiated the currently
             *         executing message on the other chain. Will throw an error if there is no message
             *         currently being executed. Allows the recipient of a call to see who triggered it.
             *
             * @return Address of the sender of the currently executing message on the other chain.
             */
            function xDomainMessageSender() external view returns (address) {
                require(
                    xDomainMsgSender != Constants.DEFAULT_L2_SENDER,
                    "CrossDomainMessenger: xDomainMessageSender is not set"
                );
                return xDomainMsgSender;
            }
            /**
             * @notice Retrieves the next message nonce. Message version will be added to the upper two
             *         bytes of the message nonce. Message version allows us to treat messages as having
             *         different structures.
             *
             * @return Nonce of the next message to be sent, with added message version.
             */
            function messageNonce() public view returns (uint256) {
                return Encoding.encodeVersionedNonce(msgNonce, MESSAGE_VERSION);
            }
            /**
             * @notice Computes the amount of gas required to guarantee that a given message will be
             *         received on the other chain without running out of gas. Guaranteeing that a message
             *         will not run out of gas is important because this ensures that a message can always
             *         be replayed on the other chain if it fails to execute completely.
             *
             * @param _message     Message to compute the amount of required gas for.
             * @param _minGasLimit Minimum desired gas limit when message goes to target.
             *
             * @return Amount of gas required to guarantee message receipt.
             */
            function baseGas(bytes calldata _message, uint32 _minGasLimit) public pure returns (uint64) {
                return
                    // Constant overhead
                    RELAY_CONSTANT_OVERHEAD +
                    // Calldata overhead
                    (uint64(_message.length) * MIN_GAS_CALLDATA_OVERHEAD) +
                    // Dynamic overhead (EIP-150)
                    ((_minGasLimit * MIN_GAS_DYNAMIC_OVERHEAD_NUMERATOR) /
                        MIN_GAS_DYNAMIC_OVERHEAD_DENOMINATOR) +
                    // Gas reserved for the worst-case cost of 3/5 of the `CALL` opcode's dynamic gas
                    // factors. (Conservative)
                    RELAY_CALL_OVERHEAD +
                    // Relay reserved gas (to ensure execution of `relayMessage` completes after the
                    // subcontext finishes executing) (Conservative)
                    RELAY_RESERVED_GAS +
                    // Gas reserved for the execution between the `hasMinGas` check and the `CALL`
                    // opcode. (Conservative)
                    RELAY_GAS_CHECK_BUFFER;
            }
            /**
             * @notice Intializer.
             */
            // solhint-disable-next-line func-name-mixedcase
            function __CrossDomainMessenger_init() internal onlyInitializing {
                xDomainMsgSender = Constants.DEFAULT_L2_SENDER;
            }
            /**
             * @notice Sends a low-level message to the other messenger. Needs to be implemented by child
             *         contracts because the logic for this depends on the network where the messenger is
             *         being deployed.
             *
             * @param _to       Recipient of the message on the other chain.
             * @param _gasLimit Minimum gas limit the message can be executed with.
             * @param _value    Amount of ETH to send with the message.
             * @param _data     Message data.
             */
            function _sendMessage(
                address _to,
                uint64 _gasLimit,
                uint256 _value,
                bytes memory _data
            ) internal virtual;
            /**
             * @notice Checks whether the message is coming from the other messenger. Implemented by child
             *         contracts because the logic for this depends on the network where the messenger is
             *         being deployed.
             *
             * @return Whether the message is coming from the other messenger.
             */
            function _isOtherMessenger() internal view virtual returns (bool);
            /**
             * @notice Checks whether a given call target is a system address that could cause the
             *         messenger to peform an unsafe action. This is NOT a mechanism for blocking user
             *         addresses. This is ONLY used to prevent the execution of messages to specific
             *         system addresses that could cause security issues, e.g., having the
             *         CrossDomainMessenger send messages to itself.
             *
             * @param _target Address of the contract to check.
             *
             * @return Whether or not the address is an unsafe system address.
             */
            function _isUnsafeTarget(address _target) internal view virtual returns (bool);
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        import { IERC165 } from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
        /**
         * @title IKromaMintableERC20
         * @notice This interface is available on the KromaMintableERC20 contract. We declare it as a
         *         separate interface so that it can be used in custom implementations of
         *         KromaMintableERC20.
         */
        interface IKromaMintableERC20 {
            function REMOTE_TOKEN() external view returns (address);
            function BRIDGE() external view returns (address);
            function mint(address _to, uint256 _amount) external;
            function burn(address _from, uint256 _amount) external;
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
        import { IERC165 } from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
        import { Semver } from "../universal/Semver.sol";
        import { IKromaMintableERC20 } from "./IKromaMintableERC20.sol";
        /**
         * @title KromaMintableERC20
         * @notice KromaMintableERC20 is a standard extension of the base ERC20 token contract designed
         *         to allow the StandardBridge contracts to mint and burn tokens. This makes it possible to
         *         use a KromaMintableRC20 as the L2 representation of an L1 token, or vice-versa.
         *         Designed to be backwards compatible with the older StandardL2ERC20 token which was only
         *         meant for use on L2.
         */
        contract KromaMintableERC20 is IKromaMintableERC20, ERC20, Semver {
            /**
             * @notice Address of the corresponding version of this token on the remote chain.
             */
            address public immutable REMOTE_TOKEN;
            /**
             * @notice Address of the StandardBridge on this network.
             */
            address public immutable BRIDGE;
            /**
             * @notice Emitted whenever tokens are minted for an account.
             *
             * @param account Address of the account tokens are being minted for.
             * @param amount  Amount of tokens minted.
             */
            event Mint(address indexed account, uint256 amount);
            /**
             * @notice Emitted whenever tokens are burned from an account.
             *
             * @param account Address of the account tokens are being burned from.
             * @param amount  Amount of tokens burned.
             */
            event Burn(address indexed account, uint256 amount);
            /**
             * @notice A modifier that only allows the bridge to call
             */
            modifier onlyBridge() {
                require(msg.sender == BRIDGE, "KromaMintableERC20: only bridge can mint and burn");
                _;
            }
            /**
            * @custom:semver 1.0.0
             *
             * @param _bridge      Address of the L2 standard bridge.
             * @param _remoteToken Address of the corresponding L1 token.
             * @param _name        ERC20 name.
             * @param _symbol      ERC20 symbol.
             */
            constructor(
                address _bridge,
                address _remoteToken,
                string memory _name,
                string memory _symbol
            ) ERC20(_name, _symbol) Semver(1, 0, 0) {
                REMOTE_TOKEN = _remoteToken;
                BRIDGE = _bridge;
            }
            /**
             * @notice Allows the StandardBridge on this network to mint tokens.
             *
             * @param _to     Address to mint tokens to.
             * @param _amount Amount of tokens to mint.
             */
            function mint(address _to, uint256 _amount)
                external
                virtual
                override(IKromaMintableERC20)
                onlyBridge
            {
                _mint(_to, _amount);
                emit Mint(_to, _amount);
            }
            /**
             * @notice Allows the StandardBridge on this network to burn tokens.
             *
             * @param _from   Address to burn tokens from.
             * @param _amount Amount of tokens to burn.
             */
            function burn(address _from, uint256 _amount)
                external
                virtual
                override(IKromaMintableERC20)
                onlyBridge
            {
                _burn(_from, _amount);
                emit Burn(_from, _amount);
            }
            /**
             * @notice ERC165 interface check function.
             *
             * @param _interfaceId Interface ID to check.
             *
             * @return Whether or not the interface is supported by this contract.
             */
            function supportsInterface(bytes4 _interfaceId) external pure returns (bool) {
                bytes4 iface1 = type(IERC165).interfaceId;
                // Interface corresponding to the updated KromaMintableERC20 (this contract).
                bytes4 iface2 = type(IKromaMintableERC20).interfaceId;
                return _interfaceId == iface1 || _interfaceId == iface2;
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
        pragma solidity ^0.8.0;
        /**
         * @dev Interface of the ERC165 standard, as defined in the
         * https://eips.ethereum.org/EIPS/eip-165[EIP].
         *
         * Implementers can declare support of contract interfaces, which can then be
         * queried by others ({ERC165Checker}).
         *
         * For an implementation, see {ERC165}.
         */
        interface IERC165 {
            /**
             * @dev Returns true if this contract implements the interface defined by
             * `interfaceId`. See the corresponding
             * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
             * to learn more about how these ids are created.
             *
             * This function call must use less than 30 000 gas.
             */
            function supportsInterface(bytes4 interfaceId) external view returns (bool);
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)
        pragma solidity ^0.8.0;
        /**
         * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
         * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
         *
         * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
         * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
         * need to send a transaction, and thus is not required to hold Ether at all.
         */
        interface IERC20Permit {
            /**
             * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
             * given ``owner``'s signed approval.
             *
             * IMPORTANT: The same issues {IERC20-approve} has related to transaction
             * ordering also apply here.
             *
             * Emits an {Approval} event.
             *
             * Requirements:
             *
             * - `spender` cannot be the zero address.
             * - `deadline` must be a timestamp in the future.
             * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
             * over the EIP712-formatted function arguments.
             * - the signature must use ``owner``'s current nonce (see {nonces}).
             *
             * For more information on the signature format, see the
             * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
             * section].
             */
            function permit(
                address owner,
                address spender,
                uint256 value,
                uint256 deadline,
                uint8 v,
                bytes32 r,
                bytes32 s
            ) external;
            /**
             * @dev Returns the current nonce for `owner`. This value must be
             * included whenever a signature is generated for {permit}.
             *
             * Every successful call to {permit} increases ``owner``'s nonce by one. This
             * prevents a signature from being used multiple times.
             */
            function nonces(address owner) external view returns (uint256);
            /**
             * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
             */
            // solhint-disable-next-line func-name-mixedcase
            function DOMAIN_SEPARATOR() external view returns (bytes32);
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)
        pragma solidity ^0.8.0;
        import "../utils/ContextUpgradeable.sol";
        import "../proxy/utils/Initializable.sol";
        /**
         * @dev Contract module which allows children to implement an emergency stop
         * mechanism that can be triggered by an authorized account.
         *
         * This module is used through inheritance. It will make available the
         * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
         * the functions of your contract. Note that they will not be pausable by
         * simply including this module, only once the modifiers are put in place.
         */
        abstract contract PausableUpgradeable is Initializable, ContextUpgradeable {
            /**
             * @dev Emitted when the pause is triggered by `account`.
             */
            event Paused(address account);
            /**
             * @dev Emitted when the pause is lifted by `account`.
             */
            event Unpaused(address account);
            bool private _paused;
            /**
             * @dev Initializes the contract in unpaused state.
             */
            function __Pausable_init() internal onlyInitializing {
                __Pausable_init_unchained();
            }
            function __Pausable_init_unchained() internal onlyInitializing {
                _paused = false;
            }
            /**
             * @dev Modifier to make a function callable only when the contract is not paused.
             *
             * Requirements:
             *
             * - The contract must not be paused.
             */
            modifier whenNotPaused() {
                _requireNotPaused();
                _;
            }
            /**
             * @dev Modifier to make a function callable only when the contract is paused.
             *
             * Requirements:
             *
             * - The contract must be paused.
             */
            modifier whenPaused() {
                _requirePaused();
                _;
            }
            /**
             * @dev Returns true if the contract is paused, and false otherwise.
             */
            function paused() public view virtual returns (bool) {
                return _paused;
            }
            /**
             * @dev Throws if the contract is paused.
             */
            function _requireNotPaused() internal view virtual {
                require(!paused(), "Pausable: paused");
            }
            /**
             * @dev Throws if the contract is not paused.
             */
            function _requirePaused() internal view virtual {
                require(paused(), "Pausable: not paused");
            }
            /**
             * @dev Triggers stopped state.
             *
             * Requirements:
             *
             * - The contract must not be paused.
             */
            function _pause() internal virtual whenNotPaused {
                _paused = true;
                emit Paused(_msgSender());
            }
            /**
             * @dev Returns to normal state.
             *
             * Requirements:
             *
             * - The contract must be paused.
             */
            function _unpause() internal virtual whenPaused {
                _paused = false;
                emit Unpaused(_msgSender());
            }
            /**
             * @dev This empty reserved space is put in place to allow future versions to add new
             * variables without shifting down storage in the inheritance chain.
             * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
             */
            uint256[49] private __gap;
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)
        pragma solidity ^0.8.0;
        import "./IERC20.sol";
        import "./extensions/IERC20Metadata.sol";
        import "../../utils/Context.sol";
        /**
         * @dev Implementation of the {IERC20} interface.
         *
         * This implementation is agnostic to the way tokens are created. This means
         * that a supply mechanism has to be added in a derived contract using {_mint}.
         * For a generic mechanism see {ERC20PresetMinterPauser}.
         *
         * TIP: For a detailed writeup see our guide
         * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
         * to implement supply mechanisms].
         *
         * The default value of {decimals} is 18. To change this, you should override
         * this function so it returns a different value.
         *
         * We have followed general OpenZeppelin Contracts guidelines: functions revert
         * instead returning `false` on failure. This behavior is nonetheless
         * conventional and does not conflict with the expectations of ERC20
         * applications.
         *
         * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
         * This allows applications to reconstruct the allowance for all accounts just
         * by listening to said events. Other implementations of the EIP may not emit
         * these events, as it isn't required by the specification.
         *
         * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
         * functions have been added to mitigate the well-known issues around setting
         * allowances. See {IERC20-approve}.
         */
        contract ERC20 is Context, IERC20, IERC20Metadata {
            mapping(address => uint256) private _balances;
            mapping(address => mapping(address => uint256)) private _allowances;
            uint256 private _totalSupply;
            string private _name;
            string private _symbol;
            /**
             * @dev Sets the values for {name} and {symbol}.
             *
             * All two of these values are immutable: they can only be set once during
             * construction.
             */
            constructor(string memory name_, string memory symbol_) {
                _name = name_;
                _symbol = symbol_;
            }
            /**
             * @dev Returns the name of the token.
             */
            function name() public view virtual override returns (string memory) {
                return _name;
            }
            /**
             * @dev Returns the symbol of the token, usually a shorter version of the
             * name.
             */
            function symbol() public view virtual override returns (string memory) {
                return _symbol;
            }
            /**
             * @dev Returns the number of decimals used to get its user representation.
             * For example, if `decimals` equals `2`, a balance of `505` tokens should
             * be displayed to a user as `5.05` (`505 / 10 ** 2`).
             *
             * Tokens usually opt for a value of 18, imitating the relationship between
             * Ether and Wei. This is the default value returned by this function, unless
             * it's overridden.
             *
             * NOTE: This information is only used for _display_ purposes: it in
             * no way affects any of the arithmetic of the contract, including
             * {IERC20-balanceOf} and {IERC20-transfer}.
             */
            function decimals() public view virtual override returns (uint8) {
                return 18;
            }
            /**
             * @dev See {IERC20-totalSupply}.
             */
            function totalSupply() public view virtual override returns (uint256) {
                return _totalSupply;
            }
            /**
             * @dev See {IERC20-balanceOf}.
             */
            function balanceOf(address account) public view virtual override returns (uint256) {
                return _balances[account];
            }
            /**
             * @dev See {IERC20-transfer}.
             *
             * Requirements:
             *
             * - `to` cannot be the zero address.
             * - the caller must have a balance of at least `amount`.
             */
            function transfer(address to, uint256 amount) public virtual override returns (bool) {
                address owner = _msgSender();
                _transfer(owner, to, amount);
                return true;
            }
            /**
             * @dev See {IERC20-allowance}.
             */
            function allowance(address owner, address spender) public view virtual override returns (uint256) {
                return _allowances[owner][spender];
            }
            /**
             * @dev See {IERC20-approve}.
             *
             * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
             * `transferFrom`. This is semantically equivalent to an infinite approval.
             *
             * Requirements:
             *
             * - `spender` cannot be the zero address.
             */
            function approve(address spender, uint256 amount) public virtual override returns (bool) {
                address owner = _msgSender();
                _approve(owner, spender, amount);
                return true;
            }
            /**
             * @dev See {IERC20-transferFrom}.
             *
             * Emits an {Approval} event indicating the updated allowance. This is not
             * required by the EIP. See the note at the beginning of {ERC20}.
             *
             * NOTE: Does not update the allowance if the current allowance
             * is the maximum `uint256`.
             *
             * Requirements:
             *
             * - `from` and `to` cannot be the zero address.
             * - `from` must have a balance of at least `amount`.
             * - the caller must have allowance for ``from``'s tokens of at least
             * `amount`.
             */
            function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
                address spender = _msgSender();
                _spendAllowance(from, spender, amount);
                _transfer(from, to, amount);
                return true;
            }
            /**
             * @dev Atomically increases the allowance granted to `spender` by the caller.
             *
             * This is an alternative to {approve} that can be used as a mitigation for
             * problems described in {IERC20-approve}.
             *
             * Emits an {Approval} event indicating the updated allowance.
             *
             * Requirements:
             *
             * - `spender` cannot be the zero address.
             */
            function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
                address owner = _msgSender();
                _approve(owner, spender, allowance(owner, spender) + addedValue);
                return true;
            }
            /**
             * @dev Atomically decreases the allowance granted to `spender` by the caller.
             *
             * This is an alternative to {approve} that can be used as a mitigation for
             * problems described in {IERC20-approve}.
             *
             * Emits an {Approval} event indicating the updated allowance.
             *
             * Requirements:
             *
             * - `spender` cannot be the zero address.
             * - `spender` must have allowance for the caller of at least
             * `subtractedValue`.
             */
            function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
                address owner = _msgSender();
                uint256 currentAllowance = allowance(owner, spender);
                require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
                unchecked {
                    _approve(owner, spender, currentAllowance - subtractedValue);
                }
                return true;
            }
            /**
             * @dev Moves `amount` of tokens from `from` to `to`.
             *
             * This internal function is equivalent to {transfer}, and can be used to
             * e.g. implement automatic token fees, slashing mechanisms, etc.
             *
             * Emits a {Transfer} event.
             *
             * Requirements:
             *
             * - `from` cannot be the zero address.
             * - `to` cannot be the zero address.
             * - `from` must have a balance of at least `amount`.
             */
            function _transfer(address from, address to, uint256 amount) internal virtual {
                require(from != address(0), "ERC20: transfer from the zero address");
                require(to != address(0), "ERC20: transfer to the zero address");
                _beforeTokenTransfer(from, to, amount);
                uint256 fromBalance = _balances[from];
                require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
                unchecked {
                    _balances[from] = fromBalance - amount;
                    // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
                    // decrementing then incrementing.
                    _balances[to] += amount;
                }
                emit Transfer(from, to, amount);
                _afterTokenTransfer(from, to, amount);
            }
            /** @dev Creates `amount` tokens and assigns them to `account`, increasing
             * the total supply.
             *
             * Emits a {Transfer} event with `from` set to the zero address.
             *
             * Requirements:
             *
             * - `account` cannot be the zero address.
             */
            function _mint(address account, uint256 amount) internal virtual {
                require(account != address(0), "ERC20: mint to the zero address");
                _beforeTokenTransfer(address(0), account, amount);
                _totalSupply += amount;
                unchecked {
                    // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
                    _balances[account] += amount;
                }
                emit Transfer(address(0), account, amount);
                _afterTokenTransfer(address(0), account, amount);
            }
            /**
             * @dev Destroys `amount` tokens from `account`, reducing the
             * total supply.
             *
             * Emits a {Transfer} event with `to` set to the zero address.
             *
             * Requirements:
             *
             * - `account` cannot be the zero address.
             * - `account` must have at least `amount` tokens.
             */
            function _burn(address account, uint256 amount) internal virtual {
                require(account != address(0), "ERC20: burn from the zero address");
                _beforeTokenTransfer(account, address(0), amount);
                uint256 accountBalance = _balances[account];
                require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
                unchecked {
                    _balances[account] = accountBalance - amount;
                    // Overflow not possible: amount <= accountBalance <= totalSupply.
                    _totalSupply -= amount;
                }
                emit Transfer(account, address(0), amount);
                _afterTokenTransfer(account, address(0), amount);
            }
            /**
             * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
             *
             * This internal function is equivalent to `approve`, and can be used to
             * e.g. set automatic allowances for certain subsystems, etc.
             *
             * Emits an {Approval} event.
             *
             * Requirements:
             *
             * - `owner` cannot be the zero address.
             * - `spender` cannot be the zero address.
             */
            function _approve(address owner, address spender, uint256 amount) internal virtual {
                require(owner != address(0), "ERC20: approve from the zero address");
                require(spender != address(0), "ERC20: approve to the zero address");
                _allowances[owner][spender] = amount;
                emit Approval(owner, spender, amount);
            }
            /**
             * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
             *
             * Does not update the allowance amount in case of infinite allowance.
             * Revert if not enough allowance is available.
             *
             * Might emit an {Approval} event.
             */
            function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
                uint256 currentAllowance = allowance(owner, spender);
                if (currentAllowance != type(uint256).max) {
                    require(currentAllowance >= amount, "ERC20: insufficient allowance");
                    unchecked {
                        _approve(owner, spender, currentAllowance - amount);
                    }
                }
            }
            /**
             * @dev Hook that is called before any transfer of tokens. This includes
             * minting and burning.
             *
             * Calling conditions:
             *
             * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
             * will be transferred to `to`.
             * - when `from` is zero, `amount` tokens will be minted for `to`.
             * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
             * - `from` and `to` are never both zero.
             *
             * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
             */
            function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}
            /**
             * @dev Hook that is called after any transfer of tokens. This includes
             * minting and burning.
             *
             * Calling conditions:
             *
             * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
             * has been transferred to `to`.
             * - when `from` is zero, `amount` tokens have been minted for `to`.
             * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
             * - `from` and `to` are never both zero.
             *
             * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
             */
            function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
        pragma solidity ^0.8.0;
        import "../IERC20.sol";
        /**
         * @dev Interface for the optional metadata functions from the ERC20 standard.
         *
         * _Available since v4.1._
         */
        interface IERC20Metadata is IERC20 {
            /**
             * @dev Returns the name of the token.
             */
            function name() external view returns (string memory);
            /**
             * @dev Returns the symbol of the token.
             */
            function symbol() external view returns (string memory);
            /**
             * @dev Returns the decimals places of the token.
             */
            function decimals() external view returns (uint8);
        }
        

        File 3 of 4: Proxy
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        /**
         * @title Proxy
         * @notice Proxy is a transparent proxy that passes through the call if the caller is the owner or
         *         if the caller is address(0), meaning that the call originated from an off-chain
         *         simulation.
         */
        contract Proxy {
            /**
             * @notice The storage slot that holds the address of the implementation.
             *         bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1)
             */
            bytes32 internal constant IMPLEMENTATION_KEY =
                0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
            /**
             * @notice The storage slot that holds the address of the owner.
             *         bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1)
             */
            bytes32 internal constant OWNER_KEY =
                0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
            /**
             * @notice An event that is emitted each time the implementation is changed. This event is part
             *         of the EIP-1967 specification.
             *
             * @param implementation The address of the implementation contract
             */
            event Upgraded(address indexed implementation);
            /**
             * @notice An event that is emitted each time the owner is upgraded. This event is part of the
             *         EIP-1967 specification.
             *
             * @param previousAdmin The previous owner of the contract
             * @param newAdmin      The new owner of the contract
             */
            event AdminChanged(address previousAdmin, address newAdmin);
            /**
             * @notice A modifier that reverts if not called by the owner or by address(0) to allow
             *         eth_call to interact with this proxy without needing to use low-level storage
             *         inspection. We assume that nobody is able to trigger calls from address(0) during
             *         normal EVM execution.
             */
            modifier proxyCallIfNotAdmin() {
                if (msg.sender == _getAdmin() || msg.sender == address(0)) {
                    _;
                } else {
                    // This WILL halt the call frame on completion.
                    _doProxyCall();
                }
            }
            /**
             * @notice Sets the initial admin during contract deployment. Admin address is stored at the
             *         EIP-1967 admin storage slot so that accidental storage collision with the
             *         implementation is not possible.
             *
             * @param _admin Address of the initial contract admin. Admin as the ability to access the
             *               transparent proxy interface.
             */
            constructor(address _admin) {
                _changeAdmin(_admin);
            }
            // slither-disable-next-line locked-ether
            receive() external payable {
                // Proxy call by default.
                _doProxyCall();
            }
            // slither-disable-next-line locked-ether
            fallback() external payable {
                // Proxy call by default.
                _doProxyCall();
            }
            /**
             * @notice Set the implementation contract address. The code at the given address will execute
             *         when this contract is called.
             *
             * @param _implementation Address of the implementation contract.
             */
            function upgradeTo(address _implementation) public virtual proxyCallIfNotAdmin {
                _setImplementation(_implementation);
            }
            /**
             * @notice Set the implementation and call a function in a single transaction. Useful to ensure
             *         atomic execution of initialization-based upgrades.
             *
             * @param _implementation Address of the implementation contract.
             * @param _data           Calldata to delegatecall the new implementation with.
             */
            function upgradeToAndCall(address _implementation, bytes calldata _data)
                public
                payable
                virtual
                proxyCallIfNotAdmin
                returns (bytes memory)
            {
                _setImplementation(_implementation);
                (bool success, bytes memory returndata) = _implementation.delegatecall(_data);
                require(success, "Proxy: delegatecall to new implementation contract failed");
                return returndata;
            }
            /**
             * @notice Changes the owner of the proxy contract. Only callable by the owner.
             *
             * @param _admin New owner of the proxy contract.
             */
            function changeAdmin(address _admin) public virtual proxyCallIfNotAdmin {
                _changeAdmin(_admin);
            }
            /**
             * @notice Gets the owner of the proxy contract.
             *
             * @return Owner address.
             */
            function admin() public virtual proxyCallIfNotAdmin returns (address) {
                return _getAdmin();
            }
            /**
             * @notice Queries the implementation address.
             *
             * @return Implementation address.
             */
            function implementation() public virtual proxyCallIfNotAdmin returns (address) {
                return _getImplementation();
            }
            /**
             * @notice Sets the implementation address.
             *
             * @param _implementation New implementation address.
             */
            function _setImplementation(address _implementation) internal {
                assembly {
                    sstore(IMPLEMENTATION_KEY, _implementation)
                }
                emit Upgraded(_implementation);
            }
            /**
             * @notice Changes the owner of the proxy contract.
             *
             * @param _admin New owner of the proxy contract.
             */
            function _changeAdmin(address _admin) internal {
                address previous = _getAdmin();
                assembly {
                    sstore(OWNER_KEY, _admin)
                }
                emit AdminChanged(previous, _admin);
            }
            /**
             * @notice Performs the proxy call via a delegatecall.
             */
            function _doProxyCall() internal {
                address impl = _getImplementation();
                require(impl != address(0), "Proxy: implementation not initialized");
                assembly {
                    // Copy calldata into memory at 0x0....calldatasize.
                    calldatacopy(0x0, 0x0, calldatasize())
                    // Perform the delegatecall, make sure to pass all available gas.
                    let success := delegatecall(gas(), impl, 0x0, calldatasize(), 0x0, 0x0)
                    // Copy returndata into memory at 0x0....returndatasize. Note that this *will*
                    // overwrite the calldata that we just copied into memory but that doesn't really
                    // matter because we'll be returning in a second anyway.
                    returndatacopy(0x0, 0x0, returndatasize())
                    // Success == 0 means a revert. We'll revert too and pass the data up.
                    if iszero(success) {
                        revert(0x0, returndatasize())
                    }
                    // Otherwise we'll just return and pass the data up.
                    return(0x0, returndatasize())
                }
            }
            /**
             * @notice Queries the implementation address.
             *
             * @return Implementation address.
             */
            function _getImplementation() internal view returns (address) {
                address impl;
                assembly {
                    impl := sload(IMPLEMENTATION_KEY)
                }
                return impl;
            }
            /**
             * @notice Queries the owner of the proxy contract.
             *
             * @return Owner address.
             */
            function _getAdmin() internal view returns (address) {
                address owner;
                assembly {
                    owner := sload(OWNER_KEY)
                }
                return owner;
            }
        }
        

        File 4 of 4: SystemConfig
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import {
            OwnableUpgradeable
        } from "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
        import { Constants } from "../libraries/Constants.sol";
        import { Semver } from "../universal/Semver.sol";
        import { ResourceMetering } from "./ResourceMetering.sol";
        /**
         * @title SystemConfig
         * @notice The SystemConfig contract is used to manage configuration of a Kroma network. All
         *         configuration is stored on L1 and picked up by L2 as part of the derivation of the L2
         *         chain.
         */
        contract SystemConfig is OwnableUpgradeable, Semver {
            /**
             * @notice Enum representing different types of updates.
             *
             * @custom:value BATCHER                 Represents an update to the batcher hash.
             * @custom:value GAS_CONFIG              Represents an update to txn fee config on L2.
             * @custom:value GAS_LIMIT               Represents an update to gas limit on L2.
             * @custom:value UNSAFE_BLOCK_SIGNER     Represents an update to the signer key for unsafe
             *                                       block distribution.
             * @custom:value VALIDATOR_REWARD_SCALAR Represents an update to validator reward scalar.
             */
            enum UpdateType {
                BATCHER,
                GAS_CONFIG,
                GAS_LIMIT,
                UNSAFE_BLOCK_SIGNER,
                VALIDATOR_REWARD_SCALAR
            }
            /**
             * @notice Version identifier, used for upgrades.
             */
            uint256 public constant VERSION = 0;
            /**
             * @notice Storage slot that the unsafe block signer is stored at. Storing it at this
             *         deterministic storage slot allows for decoupling the storage layout from the way
             *         that `solc` lays out storage. The `kroma-node` uses a storage proof to fetch this value.
             */
            bytes32 public constant UNSAFE_BLOCK_SIGNER_SLOT = keccak256("systemconfig.unsafeblocksigner");
            /**
             * @notice Fixed L2 gas overhead. Used as part of the L2 fee calculation.
             */
            uint256 public overhead;
            /**
             * @notice Dynamic L2 gas overhead. Used as part of the L2 fee calculation.
             */
            uint256 public scalar;
            /**
             * @notice Identifier for the batcher. For version 1 of this configuration, this is represented
             *         as an address left-padded with zeros to 32 bytes.
             */
            bytes32 public batcherHash;
            /**
             * @notice L2 block gas limit.
             */
            uint64 public gasLimit;
            /**
             * @notice The configuration for the deposit fee market. Used by the KromaPortal
             *         to meter the cost of buying L2 gas on L1. Set as internal and wrapped with a getter
             *         so that the struct is returned instead of a tuple.
             */
            ResourceMetering.ResourceConfig internal _resourceConfig;
            /**
             * @notice The scalar value to distribute transaction fees as validator reward.
             *         The denominator is 10000, so the ratio is expressed in 4 decimal places.
             */
            uint256 public validatorRewardScalar;
            /**
             * @notice Emitted when configuration is updated
             *
             * @param version    SystemConfig version.
             * @param updateType Type of update.
             * @param data       Encoded update data.
             */
            event ConfigUpdate(uint256 indexed version, UpdateType indexed updateType, bytes data);
            /**
             * @custom:semver 1.0.0
             *
             * @param _owner                 Initial owner of the contract.
             * @param _overhead              Initial overhead value.
             * @param _scalar                Initial scalar value.
             * @param _batcherHash           Initial batcher hash.
             * @param _gasLimit              Initial gas limit.
             * @param _unsafeBlockSigner     Initial unsafe block signer address.
             * @param _config                Initial resource config.
             * @param _validatorRewardScalar Initial validator reward scalar.
             */
            constructor(
                address _owner,
                uint256 _overhead,
                uint256 _scalar,
                bytes32 _batcherHash,
                uint64 _gasLimit,
                address _unsafeBlockSigner,
                ResourceMetering.ResourceConfig memory _config,
                uint256 _validatorRewardScalar
            ) Semver(1, 0, 0) {
                initialize(
                    _owner,
                    _overhead,
                    _scalar,
                    _batcherHash,
                    _gasLimit,
                    _unsafeBlockSigner,
                    _config,
                    _validatorRewardScalar
                );
            }
            /**
             * @notice Initializer. The resource config must be set before the
             *         require check.
             *
             * @param _owner                 Initial owner of the contract.
             * @param _overhead              Initial overhead value.
             * @param _scalar                Initial scalar value.
             * @param _batcherHash           Initial batcher hash.
             * @param _gasLimit              Initial gas limit.
             * @param _unsafeBlockSigner     Initial unsafe block signer address.
             * @param _config                Initial ResourceConfig.
             * @param _validatorRewardScalar Initial validator reward scalar.
             */
            function initialize(
                address _owner,
                uint256 _overhead,
                uint256 _scalar,
                bytes32 _batcherHash,
                uint64 _gasLimit,
                address _unsafeBlockSigner,
                ResourceMetering.ResourceConfig memory _config,
                uint256 _validatorRewardScalar
            ) public initializer {
                __Ownable_init();
                transferOwnership(_owner);
                overhead = _overhead;
                scalar = _scalar;
                batcherHash = _batcherHash;
                gasLimit = _gasLimit;
                _setUnsafeBlockSigner(_unsafeBlockSigner);
                _setResourceConfig(_config);
                require(_gasLimit >= minimumGasLimit(), "SystemConfig: gas limit too low");
                validatorRewardScalar = _validatorRewardScalar;
            }
            /**
             * @notice Returns the minimum L2 gas limit that can be safely set for the system to
             *         operate. The L2 gas limit must be larger than or equal to the amount of
             *         gas that is allocated for deposits per block plus the amount of gas that
             *         is allocated for the system transaction.
             *         This function is used to determine if changes to parameters are safe.
             *
             * @return uint64
             */
            function minimumGasLimit() public view returns (uint64) {
                return uint64(_resourceConfig.maxResourceLimit) + uint64(_resourceConfig.systemTxMaxGas);
            }
            /**
             * @notice High level getter for the unsafe block signer address. Unsafe blocks can be
             *         propagated across the p2p network if they are signed by the key corresponding to
             *         this address.
             *
             * @return Address of the unsafe block signer.
             */
            // solhint-disable-next-line ordering
            function unsafeBlockSigner() external view returns (address) {
                address addr;
                bytes32 slot = UNSAFE_BLOCK_SIGNER_SLOT;
                assembly {
                    addr := sload(slot)
                }
                return addr;
            }
            /**
             * @notice Updates the unsafe block signer address.
             *
             * @param _unsafeBlockSigner New unsafe block signer address.
             */
            function setUnsafeBlockSigner(address _unsafeBlockSigner) external onlyOwner {
                _setUnsafeBlockSigner(_unsafeBlockSigner);
                bytes memory data = abi.encode(_unsafeBlockSigner);
                emit ConfigUpdate(VERSION, UpdateType.UNSAFE_BLOCK_SIGNER, data);
            }
            /**
             * @notice Updates the batcher hash.
             *
             * @param _batcherHash New batcher hash.
             */
            function setBatcherHash(bytes32 _batcherHash) external onlyOwner {
                batcherHash = _batcherHash;
                bytes memory data = abi.encode(_batcherHash);
                emit ConfigUpdate(VERSION, UpdateType.BATCHER, data);
            }
            /**
             * @notice Updates gas config.
             *
             * @param _overhead New overhead value.
             * @param _scalar   New scalar value.
             */
            function setGasConfig(uint256 _overhead, uint256 _scalar) external onlyOwner {
                overhead = _overhead;
                scalar = _scalar;
                bytes memory data = abi.encode(_overhead, _scalar);
                emit ConfigUpdate(VERSION, UpdateType.GAS_CONFIG, data);
            }
            /**
             * @notice Updates the L2 gas limit.
             *
             * @param _gasLimit New gas limit.
             */
            function setGasLimit(uint64 _gasLimit) external onlyOwner {
                require(_gasLimit >= minimumGasLimit(), "SystemConfig: gas limit too low");
                gasLimit = _gasLimit;
                bytes memory data = abi.encode(_gasLimit);
                emit ConfigUpdate(VERSION, UpdateType.GAS_LIMIT, data);
            }
            /**
             * @notice Low level setter for the unsafe block signer address. This function exists to
             *         deduplicate code around storing the unsafeBlockSigner address in storage.
             *
             * @param _unsafeBlockSigner New unsafeBlockSigner value.
             */
            function _setUnsafeBlockSigner(address _unsafeBlockSigner) internal {
                bytes32 slot = UNSAFE_BLOCK_SIGNER_SLOT;
                assembly {
                    sstore(slot, _unsafeBlockSigner)
                }
            }
            /**
             * @notice A getter for the resource config. Ensures that the struct is
             *         returned instead of a tuple.
             *
             * @return ResourceConfig
             */
            function resourceConfig() external view returns (ResourceMetering.ResourceConfig memory) {
                return _resourceConfig;
            }
            /**
             * @notice An external setter for the resource config. In the future, this
             *         method may emit an event that the `kroma-node` picks up for when the
             *         resource config is changed.
             *
             * @param _config The new resource config values.
             */
            function setResourceConfig(ResourceMetering.ResourceConfig memory _config) external onlyOwner {
                _setResourceConfig(_config);
            }
            /**
             * @notice An internal setter for the resource config. Ensures that the
             *         config is sane before storing it by checking for invariants.
             *
             * @param _config The new resource config.
             */
            function _setResourceConfig(ResourceMetering.ResourceConfig memory _config) internal {
                // Min base fee must be less than or equal to max base fee.
                require(
                    _config.minimumBaseFee <= _config.maximumBaseFee,
                    "SystemConfig: min base fee must be less than max base"
                );
                // Base fee change denominator must be greater than 1.
                require(
                    _config.baseFeeMaxChangeDenominator > 1,
                    "SystemConfig: denominator must be larger than 1"
                );
                // Max resource limit plus system tx gas must be less than or equal to the L2 gas limit.
                // The gas limit must be increased before these values can be increased.
                require(
                    _config.maxResourceLimit + _config.systemTxMaxGas <= gasLimit,
                    "SystemConfig: gas limit too low"
                );
                // Elasticity multiplier must be greater than 0.
                require(
                    _config.elasticityMultiplier > 0,
                    "SystemConfig: elasticity multiplier cannot be 0"
                );
                // No precision loss when computing target resource limit.
                require(
                    ((_config.maxResourceLimit / _config.elasticityMultiplier) *
                        _config.elasticityMultiplier) == _config.maxResourceLimit,
                    "SystemConfig: precision loss with target resource limit"
                );
                _resourceConfig = _config;
            }
            /**
             * @notice Updates the validator reward scalar.
             *
             * @param _validatorRewardScalar New validator reward scalar.
             */
            function setValidatorRewardScalar(uint256 _validatorRewardScalar) external onlyOwner {
                require(
                    _validatorRewardScalar <= Constants.VALIDATOR_REWARD_DENOMINATOR,
                    "SystemConfig: the max value of validator reward scalar has been exceeded"
                );
                validatorRewardScalar = _validatorRewardScalar;
                bytes memory data = abi.encode(_validatorRewardScalar);
                emit ConfigUpdate(VERSION, UpdateType.VALIDATOR_REWARD_SCALAR, data);
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)
        pragma solidity ^0.8.0;
        import "../utils/ContextUpgradeable.sol";
        import "../proxy/utils/Initializable.sol";
        /**
         * @dev Contract module which provides a basic access control mechanism, where
         * there is an account (an owner) that can be granted exclusive access to
         * specific functions.
         *
         * By default, the owner account will be the one that deploys the contract. This
         * can later be changed with {transferOwnership}.
         *
         * This module is used through inheritance. It will make available the modifier
         * `onlyOwner`, which can be applied to your functions to restrict their use to
         * the owner.
         */
        abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
            address private _owner;
            event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
            /**
             * @dev Initializes the contract setting the deployer as the initial owner.
             */
            function __Ownable_init() internal onlyInitializing {
                __Ownable_init_unchained();
            }
            function __Ownable_init_unchained() internal onlyInitializing {
                _transferOwnership(_msgSender());
            }
            /**
             * @dev Throws if called by any account other than the owner.
             */
            modifier onlyOwner() {
                _checkOwner();
                _;
            }
            /**
             * @dev Returns the address of the current owner.
             */
            function owner() public view virtual returns (address) {
                return _owner;
            }
            /**
             * @dev Throws if the sender is not the owner.
             */
            function _checkOwner() internal view virtual {
                require(owner() == _msgSender(), "Ownable: caller is not the owner");
            }
            /**
             * @dev Leaves the contract without owner. It will not be possible to call
             * `onlyOwner` functions. Can only be called by the current owner.
             *
             * NOTE: Renouncing ownership will leave the contract without an owner,
             * thereby disabling any functionality that is only available to the owner.
             */
            function renounceOwnership() public virtual onlyOwner {
                _transferOwnership(address(0));
            }
            /**
             * @dev Transfers ownership of the contract to a new account (`newOwner`).
             * Can only be called by the current owner.
             */
            function transferOwnership(address newOwner) public virtual onlyOwner {
                require(newOwner != address(0), "Ownable: new owner is the zero address");
                _transferOwnership(newOwner);
            }
            /**
             * @dev Transfers ownership of the contract to a new account (`newOwner`).
             * Internal function without access restriction.
             */
            function _transferOwnership(address newOwner) internal virtual {
                address oldOwner = _owner;
                _owner = newOwner;
                emit OwnershipTransferred(oldOwner, newOwner);
            }
            /**
             * @dev This empty reserved space is put in place to allow future versions to add new
             * variables without shifting down storage in the inheritance chain.
             * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
             */
            uint256[49] private __gap;
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.0;
        import { ResourceMetering } from "../L1/ResourceMetering.sol";
        /**
         * @title Constants
         * @notice Constants is a library for storing constants. Simple! Don't put everything in here, just
         *         the stuff used in multiple contracts. Constants that only apply to a single contract
         *         should be defined in that contract instead.
         */
        library Constants {
            /**
             * @notice Special address to be used as the tx origin for gas estimation calls in the
             *         KromaPortal and CrossDomainMessenger calls. You only need to use this address if
             *         the minimum gas limit specified by the user is not actually enough to execute the
             *         given message and you're attempting to estimate the actual necessary gas limit. We
             *         use address(1) because it's the ecrecover precompile and therefore guaranteed to
             *         never have any code on any EVM chain.
             */
            address internal constant ESTIMATION_ADDRESS = address(1);
            /**
             * @notice Value used for the L2 sender storage slot in both the KromaPortal and the
             *         CrossDomainMessenger contracts before an actual sender is set. This value is
             *         non-zero to reduce the gas cost of message passing transactions.
             */
            address internal constant DEFAULT_L2_SENDER = 0x000000000000000000000000000000000000dEaD;
            /**
             * @notice Returns the default values for the ResourceConfig. These are the recommended values
             *         for a production network.
             */
            function DEFAULT_RESOURCE_CONFIG()
                internal
                pure
                returns (ResourceMetering.ResourceConfig memory)
            {
                ResourceMetering.ResourceConfig memory config = ResourceMetering.ResourceConfig({
                    maxResourceLimit: 20_000_000,
                    elasticityMultiplier: 10,
                    baseFeeMaxChangeDenominator: 8,
                    minimumBaseFee: 1 gwei,
                    systemTxMaxGas: 1_000_000,
                    maximumBaseFee: type(uint128).max
                });
                return config;
            }
            /**
             * @notice The denominator of the validator reward.
             *         DO NOT change this value if the L2 chain is already operational.
             */
            uint256 internal constant VALIDATOR_REWARD_DENOMINATOR = 10000;
            /**
             * @notice An address that identifies that current submission round is a public round.
             */
            address internal constant VALIDATOR_PUBLIC_ROUND_ADDRESS = address(type(uint160).max);
        }
        // SPDX-License-Identifier: MIT
        pragma solidity ^0.8.15;
        import { Strings } from "@openzeppelin/contracts/utils/Strings.sol";
        /**
         * @title Semver
         * @notice Semver is a simple contract for managing contract versions.
         */
        contract Semver {
            /**
             * @notice Contract version number (major).
             */
            uint256 private immutable MAJOR_VERSION;
            /**
             * @notice Contract version number (minor).
             */
            uint256 private immutable MINOR_VERSION;
            /**
             * @notice Contract version number (patch).
             */
            uint256 private immutable PATCH_VERSION;
            /**
             * @param _major Version number (major).
             * @param _minor Version number (minor).
             * @param _patch Version number (patch).
             */
            constructor(
                uint256 _major,
                uint256 _minor,
                uint256 _patch
            ) {
                MAJOR_VERSION = _major;
                MINOR_VERSION = _minor;
                PATCH_VERSION = _patch;
            }
            /**
             * @notice Returns the full semver contract version.
             *
             * @return Semver contract version as a string.
             */
            function version() public view virtual returns (string memory) {
                return
                    string(
                        abi.encodePacked(
                            Strings.toString(MAJOR_VERSION),
                            ".",
                            Strings.toString(MINOR_VERSION),
                            ".",
                            Strings.toString(PATCH_VERSION)
                        )
                    );
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Initializable } from "@openzeppelin/contracts/proxy/utils/Initializable.sol";
        import { Math } from "@openzeppelin/contracts/utils/math/Math.sol";
        import { Arithmetic } from "../libraries/Arithmetic.sol";
        import { Burn } from "../libraries/Burn.sol";
        /**
         * @custom:upgradeable
         * @title ResourceMetering
         * @notice ResourceMetering implements an EIP-1559 style resource metering system where pricing
         *         updates automatically based on current demand.
         */
        abstract contract ResourceMetering is Initializable {
            /**
             * @notice Represents the various parameters that control the way in which resources are
             *         metered. Corresponds to the EIP-1559 resource metering system.
             *
             * @custom:field prevBaseFee   Base fee from the previous block(s).
             * @custom:field prevBoughtGas Amount of gas bought so far in the current block.
             * @custom:field prevBlockNum  Last block number that the base fee was updated.
             */
            struct ResourceParams {
                uint128 prevBaseFee;
                uint64 prevBoughtGas;
                uint64 prevBlockNum;
            }
            /**
             * @notice Represents the configuration for the EIP-1559 based curve for the deposit gas
             *         market. These values should be set with care as it is possible to set them in
             *         a way that breaks the deposit gas market. The target resource limit is defined as
             *         maxResourceLimit / elasticityMultiplier. This struct was designed to fit within a
             *         single word. There is additional space for additions in the future.
             *
             * @custom:field maxResourceLimit             Represents the maximum amount of deposit gas that
             *                                            can be purchased per block.
             * @custom:field elasticityMultiplier         Determines the target resource limit along with
             *                                            the resource limit.
             * @custom:field baseFeeMaxChangeDenominator  Determines max change on fee per block.
             * @custom:field minimumBaseFee               The min deposit base fee, it is clamped to this
             *                                            value.
             * @custom:field systemTxMaxGas               The amount of gas supplied to the system
             *                                            transaction. This should be set to the same number
             *                                            that the kroma-node sets as the gas limit for the
             *                                            system transaction.
             * @custom:field maximumBaseFee               The max deposit base fee, it is clamped to this
             *                                            value.
             */
            struct ResourceConfig {
                uint32 maxResourceLimit;
                uint8 elasticityMultiplier;
                uint8 baseFeeMaxChangeDenominator;
                uint32 minimumBaseFee;
                uint32 systemTxMaxGas;
                uint128 maximumBaseFee;
            }
            /**
             * @notice EIP-1559 style gas parameters.
             */
            ResourceParams public params;
            /**
             * @notice Reserve extra slots (to a total of 50) in the storage layout for future upgrades.
             */
            uint256[48] private __gap;
            /**
             * @notice Meters access to a function based an amount of a requested resource.
             *
             * @param _amount Amount of the resource requested.
             */
            modifier metered(uint64 _amount) {
                // Record initial gas amount so we can refund for it later.
                uint256 initialGas = gasleft();
                // Run the underlying function.
                _;
                // Run the metering function.
                _metered(_amount, initialGas);
            }
            /**
             * @notice An internal function that holds all of the logic for metering a resource.
             *
             * @param _amount     Amount of the resource requested.
             * @param _initialGas The amount of gas before any modifier execution.
             */
            function _metered(uint64 _amount, uint256 _initialGas) internal {
                // Update block number and base fee if necessary.
                uint256 blockDiff = block.number - params.prevBlockNum;
                ResourceConfig memory config = _resourceConfig();
                int256 targetResourceLimit = int256(uint256(config.maxResourceLimit)) /
                    int256(uint256(config.elasticityMultiplier));
                if (blockDiff > 0) {
                    // Handle updating EIP-1559 style gas parameters. We use EIP-1559 to restrict the rate
                    // at which deposits can be created and therefore limit the potential for deposits to
                    // spam the L2 system. Fee scheme is very similar to EIP-1559 with minor changes.
                    int256 gasUsedDelta = int256(uint256(params.prevBoughtGas)) - targetResourceLimit;
                    int256 baseFeeDelta = (int256(uint256(params.prevBaseFee)) * gasUsedDelta) /
                        (targetResourceLimit * int256(uint256(config.baseFeeMaxChangeDenominator)));
                    // Update base fee by adding the base fee delta and clamp the resulting value between
                    // min and max.
                    int256 newBaseFee = Arithmetic.clamp({
                        _value: int256(uint256(params.prevBaseFee)) + baseFeeDelta,
                        _min: int256(uint256(config.minimumBaseFee)),
                        _max: int256(uint256(config.maximumBaseFee))
                    });
                    // If we skipped more than one block, we also need to account for every empty block.
                    // Empty block means there was no demand for deposits in that block, so we should
                    // reflect this lack of demand in the fee.
                    if (blockDiff > 1) {
                        // Update the base fee by repeatedly applying the exponent 1-(1/change_denominator)
                        // blockDiff - 1 times. Simulates multiple empty blocks. Clamp the resulting value
                        // between min and max.
                        newBaseFee = Arithmetic.clamp({
                            _value: Arithmetic.cdexp({
                                _coefficient: newBaseFee,
                                _denominator: int256(uint256(config.baseFeeMaxChangeDenominator)),
                                _exponent: int256(blockDiff - 1)
                            }),
                            _min: int256(uint256(config.minimumBaseFee)),
                            _max: int256(uint256(config.maximumBaseFee))
                        });
                    }
                    // Update new base fee, reset bought gas, and update block number.
                    params.prevBaseFee = uint128(uint256(newBaseFee));
                    params.prevBoughtGas = 0;
                    params.prevBlockNum = uint64(block.number);
                }
                // Make sure we can actually buy the resource amount requested by the user.
                params.prevBoughtGas += _amount;
                require(
                    int256(uint256(params.prevBoughtGas)) <= int256(uint256(config.maxResourceLimit)),
                    "ResourceMetering: cannot buy more gas than available gas limit"
                );
                // Determine the amount of ETH to be paid.
                uint256 resourceCost = uint256(_amount) * uint256(params.prevBaseFee);
                // We currently charge for this ETH amount as an L1 gas burn, so we convert the ETH amount
                // into gas by dividing by the L1 base fee. We assume a minimum base fee of 1 gwei to avoid
                // division by zero for L1s that don't support 1559 or to avoid excessive gas burns during
                // periods of extremely low L1 demand. One-day average gas fee hasn't dipped below 1 gwei
                // during any 1 day period in the last 5 years, so should be fine.
                uint256 gasCost = resourceCost / Math.max(block.basefee, 1 gwei);
                // Give the user a refund based on the amount of gas they used to do all of the work up to
                // this point. Since we're at the end of the modifier, this should be pretty accurate. Acts
                // effectively like a dynamic stipend (with a minimum value).
                uint256 usedGas = _initialGas - gasleft();
                if (gasCost > usedGas) {
                    Burn.gas(gasCost - usedGas);
                }
            }
            /**
             * @notice Virtual function that returns the resource config. Contracts that inherit this
             *         contract must implement this function.
             *
             * @return ResourceConfig
             */
            function _resourceConfig() internal virtual returns (ResourceConfig memory);
            /**
             * @notice Sets initial resource parameter values. This function must either be called by the
             *         initializer function of an upgradeable child contract.
             */
            // solhint-disable-next-line func-name-mixedcase
            function __ResourceMetering_init() internal onlyInitializing {
                params = ResourceParams({
                    prevBaseFee: 1 gwei,
                    prevBoughtGas: 0,
                    prevBlockNum: uint64(block.number)
                });
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
        pragma solidity ^0.8.0;
        import "../proxy/utils/Initializable.sol";
        /**
         * @dev Provides information about the current execution context, including the
         * sender of the transaction and its data. While these are generally available
         * via msg.sender and msg.data, they should not be accessed in such a direct
         * manner, since when dealing with meta-transactions the account sending and
         * paying for execution may not be the actual sender (as far as an application
         * is concerned).
         *
         * This contract is only required for intermediate, library-like contracts.
         */
        abstract contract ContextUpgradeable is Initializable {
            function __Context_init() internal onlyInitializing {
            }
            function __Context_init_unchained() internal onlyInitializing {
            }
            function _msgSender() internal view virtual returns (address) {
                return msg.sender;
            }
            function _msgData() internal view virtual returns (bytes calldata) {
                return msg.data;
            }
            /**
             * @dev This empty reserved space is put in place to allow future versions to add new
             * variables without shifting down storage in the inheritance chain.
             * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
             */
            uint256[50] private __gap;
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)
        pragma solidity ^0.8.2;
        import "../../utils/AddressUpgradeable.sol";
        /**
         * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
         * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
         * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
         * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
         *
         * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
         * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
         * case an upgrade adds a module that needs to be initialized.
         *
         * For example:
         *
         * [.hljs-theme-light.nopadding]
         * ```solidity
         * contract MyToken is ERC20Upgradeable {
         *     function initialize() initializer public {
         *         __ERC20_init("MyToken", "MTK");
         *     }
         * }
         *
         * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
         *     function initializeV2() reinitializer(2) public {
         *         __ERC20Permit_init("MyToken");
         *     }
         * }
         * ```
         *
         * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
         * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
         *
         * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
         * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
         *
         * [CAUTION]
         * ====
         * Avoid leaving a contract uninitialized.
         *
         * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
         * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
         * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
         *
         * [.hljs-theme-light.nopadding]
         * ```
         * /// @custom:oz-upgrades-unsafe-allow constructor
         * constructor() {
         *     _disableInitializers();
         * }
         * ```
         * ====
         */
        abstract contract Initializable {
            /**
             * @dev Indicates that the contract has been initialized.
             * @custom:oz-retyped-from bool
             */
            uint8 private _initialized;
            /**
             * @dev Indicates that the contract is in the process of being initialized.
             */
            bool private _initializing;
            /**
             * @dev Triggered when the contract has been initialized or reinitialized.
             */
            event Initialized(uint8 version);
            /**
             * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
             * `onlyInitializing` functions can be used to initialize parent contracts.
             *
             * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
             * constructor.
             *
             * Emits an {Initialized} event.
             */
            modifier initializer() {
                bool isTopLevelCall = !_initializing;
                require(
                    (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
                    "Initializable: contract is already initialized"
                );
                _initialized = 1;
                if (isTopLevelCall) {
                    _initializing = true;
                }
                _;
                if (isTopLevelCall) {
                    _initializing = false;
                    emit Initialized(1);
                }
            }
            /**
             * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
             * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
             * used to initialize parent contracts.
             *
             * A reinitializer may be used after the original initialization step. This is essential to configure modules that
             * are added through upgrades and that require initialization.
             *
             * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
             * cannot be nested. If one is invoked in the context of another, execution will revert.
             *
             * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
             * a contract, executing them in the right order is up to the developer or operator.
             *
             * WARNING: setting the version to 255 will prevent any future reinitialization.
             *
             * Emits an {Initialized} event.
             */
            modifier reinitializer(uint8 version) {
                require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
                _initialized = version;
                _initializing = true;
                _;
                _initializing = false;
                emit Initialized(version);
            }
            /**
             * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
             * {initializer} and {reinitializer} modifiers, directly or indirectly.
             */
            modifier onlyInitializing() {
                require(_initializing, "Initializable: contract is not initializing");
                _;
            }
            /**
             * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
             * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
             * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
             * through proxies.
             *
             * Emits an {Initialized} event the first time it is successfully executed.
             */
            function _disableInitializers() internal virtual {
                require(!_initializing, "Initializable: contract is initializing");
                if (_initialized != type(uint8).max) {
                    _initialized = type(uint8).max;
                    emit Initialized(type(uint8).max);
                }
            }
            /**
             * @dev Returns the highest version that has been initialized. See {reinitializer}.
             */
            function _getInitializedVersion() internal view returns (uint8) {
                return _initialized;
            }
            /**
             * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
             */
            function _isInitializing() internal view returns (bool) {
                return _initializing;
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/Strings.sol)
        pragma solidity ^0.8.0;
        import "./math/Math.sol";
        import "./math/SignedMath.sol";
        /**
         * @dev String operations.
         */
        library Strings {
            bytes16 private constant _SYMBOLS = "0123456789abcdef";
            uint8 private constant _ADDRESS_LENGTH = 20;
            /**
             * @dev Converts a `uint256` to its ASCII `string` decimal representation.
             */
            function toString(uint256 value) internal pure returns (string memory) {
                unchecked {
                    uint256 length = Math.log10(value) + 1;
                    string memory buffer = new string(length);
                    uint256 ptr;
                    /// @solidity memory-safe-assembly
                    assembly {
                        ptr := add(buffer, add(32, length))
                    }
                    while (true) {
                        ptr--;
                        /// @solidity memory-safe-assembly
                        assembly {
                            mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                        }
                        value /= 10;
                        if (value == 0) break;
                    }
                    return buffer;
                }
            }
            /**
             * @dev Converts a `int256` to its ASCII `string` decimal representation.
             */
            function toString(int256 value) internal pure returns (string memory) {
                return string(abi.encodePacked(value < 0 ? "-" : "", toString(SignedMath.abs(value))));
            }
            /**
             * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
             */
            function toHexString(uint256 value) internal pure returns (string memory) {
                unchecked {
                    return toHexString(value, Math.log256(value) + 1);
                }
            }
            /**
             * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
             */
            function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
                bytes memory buffer = new bytes(2 * length + 2);
                buffer[0] = "0";
                buffer[1] = "x";
                for (uint256 i = 2 * length + 1; i > 1; --i) {
                    buffer[i] = _SYMBOLS[value & 0xf];
                    value >>= 4;
                }
                require(value == 0, "Strings: hex length insufficient");
                return string(buffer);
            }
            /**
             * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
             */
            function toHexString(address addr) internal pure returns (string memory) {
                return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
            }
            /**
             * @dev Returns true if the two strings are equal.
             */
            function equal(string memory a, string memory b) internal pure returns (bool) {
                return keccak256(bytes(a)) == keccak256(bytes(b));
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)
        pragma solidity ^0.8.2;
        import "../../utils/Address.sol";
        /**
         * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
         * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
         * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
         * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
         *
         * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
         * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
         * case an upgrade adds a module that needs to be initialized.
         *
         * For example:
         *
         * [.hljs-theme-light.nopadding]
         * ```solidity
         * contract MyToken is ERC20Upgradeable {
         *     function initialize() initializer public {
         *         __ERC20_init("MyToken", "MTK");
         *     }
         * }
         *
         * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
         *     function initializeV2() reinitializer(2) public {
         *         __ERC20Permit_init("MyToken");
         *     }
         * }
         * ```
         *
         * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
         * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
         *
         * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
         * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
         *
         * [CAUTION]
         * ====
         * Avoid leaving a contract uninitialized.
         *
         * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
         * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
         * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
         *
         * [.hljs-theme-light.nopadding]
         * ```
         * /// @custom:oz-upgrades-unsafe-allow constructor
         * constructor() {
         *     _disableInitializers();
         * }
         * ```
         * ====
         */
        abstract contract Initializable {
            /**
             * @dev Indicates that the contract has been initialized.
             * @custom:oz-retyped-from bool
             */
            uint8 private _initialized;
            /**
             * @dev Indicates that the contract is in the process of being initialized.
             */
            bool private _initializing;
            /**
             * @dev Triggered when the contract has been initialized or reinitialized.
             */
            event Initialized(uint8 version);
            /**
             * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
             * `onlyInitializing` functions can be used to initialize parent contracts.
             *
             * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
             * constructor.
             *
             * Emits an {Initialized} event.
             */
            modifier initializer() {
                bool isTopLevelCall = !_initializing;
                require(
                    (isTopLevelCall && _initialized < 1) || (!Address.isContract(address(this)) && _initialized == 1),
                    "Initializable: contract is already initialized"
                );
                _initialized = 1;
                if (isTopLevelCall) {
                    _initializing = true;
                }
                _;
                if (isTopLevelCall) {
                    _initializing = false;
                    emit Initialized(1);
                }
            }
            /**
             * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
             * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
             * used to initialize parent contracts.
             *
             * A reinitializer may be used after the original initialization step. This is essential to configure modules that
             * are added through upgrades and that require initialization.
             *
             * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
             * cannot be nested. If one is invoked in the context of another, execution will revert.
             *
             * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
             * a contract, executing them in the right order is up to the developer or operator.
             *
             * WARNING: setting the version to 255 will prevent any future reinitialization.
             *
             * Emits an {Initialized} event.
             */
            modifier reinitializer(uint8 version) {
                require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
                _initialized = version;
                _initializing = true;
                _;
                _initializing = false;
                emit Initialized(version);
            }
            /**
             * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
             * {initializer} and {reinitializer} modifiers, directly or indirectly.
             */
            modifier onlyInitializing() {
                require(_initializing, "Initializable: contract is not initializing");
                _;
            }
            /**
             * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
             * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
             * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
             * through proxies.
             *
             * Emits an {Initialized} event the first time it is successfully executed.
             */
            function _disableInitializers() internal virtual {
                require(!_initializing, "Initializable: contract is initializing");
                if (_initialized != type(uint8).max) {
                    _initialized = type(uint8).max;
                    emit Initialized(type(uint8).max);
                }
            }
            /**
             * @dev Returns the highest version that has been initialized. See {reinitializer}.
             */
            function _getInitializedVersion() internal view returns (uint8) {
                return _initialized;
            }
            /**
             * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
             */
            function _isInitializing() internal view returns (bool) {
                return _initializing;
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)
        pragma solidity ^0.8.0;
        /**
         * @dev Standard math utilities missing in the Solidity language.
         */
        library Math {
            enum Rounding {
                Down, // Toward negative infinity
                Up, // Toward infinity
                Zero // Toward zero
            }
            /**
             * @dev Returns the largest of two numbers.
             */
            function max(uint256 a, uint256 b) internal pure returns (uint256) {
                return a > b ? a : b;
            }
            /**
             * @dev Returns the smallest of two numbers.
             */
            function min(uint256 a, uint256 b) internal pure returns (uint256) {
                return a < b ? a : b;
            }
            /**
             * @dev Returns the average of two numbers. The result is rounded towards
             * zero.
             */
            function average(uint256 a, uint256 b) internal pure returns (uint256) {
                // (a + b) / 2 can overflow.
                return (a & b) + (a ^ b) / 2;
            }
            /**
             * @dev Returns the ceiling of the division of two numbers.
             *
             * This differs from standard division with `/` in that it rounds up instead
             * of rounding down.
             */
            function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
                // (a + b - 1) / b can overflow on addition, so we distribute.
                return a == 0 ? 0 : (a - 1) / b + 1;
            }
            /**
             * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
             * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
             * with further edits by Uniswap Labs also under MIT license.
             */
            function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
                unchecked {
                    // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
                    // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
                    // variables such that product = prod1 * 2^256 + prod0.
                    uint256 prod0; // Least significant 256 bits of the product
                    uint256 prod1; // Most significant 256 bits of the product
                    assembly {
                        let mm := mulmod(x, y, not(0))
                        prod0 := mul(x, y)
                        prod1 := sub(sub(mm, prod0), lt(mm, prod0))
                    }
                    // Handle non-overflow cases, 256 by 256 division.
                    if (prod1 == 0) {
                        // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                        // The surrounding unchecked block does not change this fact.
                        // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                        return prod0 / denominator;
                    }
                    // Make sure the result is less than 2^256. Also prevents denominator == 0.
                    require(denominator > prod1, "Math: mulDiv overflow");
                    ///////////////////////////////////////////////
                    // 512 by 256 division.
                    ///////////////////////////////////////////////
                    // Make division exact by subtracting the remainder from [prod1 prod0].
                    uint256 remainder;
                    assembly {
                        // Compute remainder using mulmod.
                        remainder := mulmod(x, y, denominator)
                        // Subtract 256 bit number from 512 bit number.
                        prod1 := sub(prod1, gt(remainder, prod0))
                        prod0 := sub(prod0, remainder)
                    }
                    // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
                    // See https://cs.stackexchange.com/q/138556/92363.
                    // Does not overflow because the denominator cannot be zero at this stage in the function.
                    uint256 twos = denominator & (~denominator + 1);
                    assembly {
                        // Divide denominator by twos.
                        denominator := div(denominator, twos)
                        // Divide [prod1 prod0] by twos.
                        prod0 := div(prod0, twos)
                        // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                        twos := add(div(sub(0, twos), twos), 1)
                    }
                    // Shift in bits from prod1 into prod0.
                    prod0 |= prod1 * twos;
                    // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
                    // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
                    // four bits. That is, denominator * inv = 1 mod 2^4.
                    uint256 inverse = (3 * denominator) ^ 2;
                    // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
                    // in modular arithmetic, doubling the correct bits in each step.
                    inverse *= 2 - denominator * inverse; // inverse mod 2^8
                    inverse *= 2 - denominator * inverse; // inverse mod 2^16
                    inverse *= 2 - denominator * inverse; // inverse mod 2^32
                    inverse *= 2 - denominator * inverse; // inverse mod 2^64
                    inverse *= 2 - denominator * inverse; // inverse mod 2^128
                    inverse *= 2 - denominator * inverse; // inverse mod 2^256
                    // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
                    // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
                    // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
                    // is no longer required.
                    result = prod0 * inverse;
                    return result;
                }
            }
            /**
             * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
             */
            function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
                uint256 result = mulDiv(x, y, denominator);
                if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
                    result += 1;
                }
                return result;
            }
            /**
             * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
             *
             * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
             */
            function sqrt(uint256 a) internal pure returns (uint256) {
                if (a == 0) {
                    return 0;
                }
                // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
                //
                // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
                // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
                //
                // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
                // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
                // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
                //
                // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
                uint256 result = 1 << (log2(a) >> 1);
                // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
                // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
                // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
                // into the expected uint128 result.
                unchecked {
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    result = (result + a / result) >> 1;
                    return min(result, a / result);
                }
            }
            /**
             * @notice Calculates sqrt(a), following the selected rounding direction.
             */
            function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
                unchecked {
                    uint256 result = sqrt(a);
                    return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
                }
            }
            /**
             * @dev Return the log in base 2, rounded down, of a positive value.
             * Returns 0 if given 0.
             */
            function log2(uint256 value) internal pure returns (uint256) {
                uint256 result = 0;
                unchecked {
                    if (value >> 128 > 0) {
                        value >>= 128;
                        result += 128;
                    }
                    if (value >> 64 > 0) {
                        value >>= 64;
                        result += 64;
                    }
                    if (value >> 32 > 0) {
                        value >>= 32;
                        result += 32;
                    }
                    if (value >> 16 > 0) {
                        value >>= 16;
                        result += 16;
                    }
                    if (value >> 8 > 0) {
                        value >>= 8;
                        result += 8;
                    }
                    if (value >> 4 > 0) {
                        value >>= 4;
                        result += 4;
                    }
                    if (value >> 2 > 0) {
                        value >>= 2;
                        result += 2;
                    }
                    if (value >> 1 > 0) {
                        result += 1;
                    }
                }
                return result;
            }
            /**
             * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
             * Returns 0 if given 0.
             */
            function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
                unchecked {
                    uint256 result = log2(value);
                    return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
                }
            }
            /**
             * @dev Return the log in base 10, rounded down, of a positive value.
             * Returns 0 if given 0.
             */
            function log10(uint256 value) internal pure returns (uint256) {
                uint256 result = 0;
                unchecked {
                    if (value >= 10 ** 64) {
                        value /= 10 ** 64;
                        result += 64;
                    }
                    if (value >= 10 ** 32) {
                        value /= 10 ** 32;
                        result += 32;
                    }
                    if (value >= 10 ** 16) {
                        value /= 10 ** 16;
                        result += 16;
                    }
                    if (value >= 10 ** 8) {
                        value /= 10 ** 8;
                        result += 8;
                    }
                    if (value >= 10 ** 4) {
                        value /= 10 ** 4;
                        result += 4;
                    }
                    if (value >= 10 ** 2) {
                        value /= 10 ** 2;
                        result += 2;
                    }
                    if (value >= 10 ** 1) {
                        result += 1;
                    }
                }
                return result;
            }
            /**
             * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
             * Returns 0 if given 0.
             */
            function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
                unchecked {
                    uint256 result = log10(value);
                    return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
                }
            }
            /**
             * @dev Return the log in base 256, rounded down, of a positive value.
             * Returns 0 if given 0.
             *
             * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
             */
            function log256(uint256 value) internal pure returns (uint256) {
                uint256 result = 0;
                unchecked {
                    if (value >> 128 > 0) {
                        value >>= 128;
                        result += 16;
                    }
                    if (value >> 64 > 0) {
                        value >>= 64;
                        result += 8;
                    }
                    if (value >> 32 > 0) {
                        value >>= 32;
                        result += 4;
                    }
                    if (value >> 16 > 0) {
                        value >>= 16;
                        result += 2;
                    }
                    if (value >> 8 > 0) {
                        result += 1;
                    }
                }
                return result;
            }
            /**
             * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
             * Returns 0 if given 0.
             */
            function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
                unchecked {
                    uint256 result = log256(value);
                    return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { Math } from "@openzeppelin/contracts/utils/math/Math.sol";
        import { SignedMath } from "@openzeppelin/contracts/utils/math/SignedMath.sol";
        import { FixedPointMathLib } from "@rari-capital/solmate/src/utils/FixedPointMathLib.sol";
        /**
         * @title Arithmetic
         * @notice Even more math than before.
         */
        library Arithmetic {
            /**
             * @notice Clamps a value between a minimum and maximum.
             *
             * @param _value The value to clamp.
             * @param _min   The minimum value.
             * @param _max   The maximum value.
             *
             * @return The clamped value.
             */
            function clamp(
                int256 _value,
                int256 _min,
                int256 _max
            ) internal pure returns (int256) {
                return SignedMath.min(SignedMath.max(_value, _min), _max);
            }
            /**
             * @notice Clamps a value between a minimum and maximum.
             *
             * @param _value The value to clamp.
             * @param _min   The minimum value.
             * @param _max   The maximum value.
             *
             * @return The clamped value.
             */
            function clamp(
                uint256 _value,
                uint256 _min,
                uint256 _max
            ) internal pure returns (uint256) {
                return Math.min(Math.max(_value, _min), _max);
            }
            /**
             * @notice (c)oefficient (d)enominator (exp)onentiation function.
             *         Returns the result of: c * (1 - 1/d)^exp.
             *
             * @param _coefficient Coefficient of the function.
             * @param _denominator Fractional denominator.
             * @param _exponent    Power function exponent.
             *
             * @return Result of c * (1 - 1/d)^exp.
             */
            function cdexp(
                int256 _coefficient,
                int256 _denominator,
                int256 _exponent
            ) internal pure returns (int256) {
                return
                    (_coefficient *
                        (FixedPointMathLib.powWad(1e18 - (1e18 / _denominator), _exponent * 1e18))) / 1e18;
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        import { SafeCall } from "./SafeCall.sol";
        /**
         * @title Burn
         * @notice Utilities for burning stuff.
         */
        library Burn {
            /**
             * Burns a given amount of ETH.
             * Note that execution engine of Kroma does not support SELFDESTRUCT opcode, so it sends ETH to zero address.
             *
             * @param _amount Amount of ETH to burn.
             */
            function eth(uint256 _amount) internal {
                SafeCall.call(address(0), gasleft(), _amount, "");
            }
            /**
             * Burns a given amount of gas.
             *
             * @param _amount Amount of gas to burn.
             */
            function gas(uint256 _amount) internal view {
                uint256 i = 0;
                uint256 initialGas = gasleft();
                while (initialGas - gasleft() < _amount) {
                    ++i;
                }
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
        pragma solidity ^0.8.1;
        /**
         * @dev Collection of functions related to the address type
         */
        library AddressUpgradeable {
            /**
             * @dev Returns true if `account` is a contract.
             *
             * [IMPORTANT]
             * ====
             * It is unsafe to assume that an address for which this function returns
             * false is an externally-owned account (EOA) and not a contract.
             *
             * Among others, `isContract` will return false for the following
             * types of addresses:
             *
             *  - an externally-owned account
             *  - a contract in construction
             *  - an address where a contract will be created
             *  - an address where a contract lived, but was destroyed
             *
             * Furthermore, `isContract` will also return true if the target contract within
             * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
             * which only has an effect at the end of a transaction.
             * ====
             *
             * [IMPORTANT]
             * ====
             * You shouldn't rely on `isContract` to protect against flash loan attacks!
             *
             * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
             * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
             * constructor.
             * ====
             */
            function isContract(address account) internal view returns (bool) {
                // This method relies on extcodesize/address.code.length, which returns 0
                // for contracts in construction, since the code is only stored at the end
                // of the constructor execution.
                return account.code.length > 0;
            }
            /**
             * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
             * `recipient`, forwarding all available gas and reverting on errors.
             *
             * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
             * of certain opcodes, possibly making contracts go over the 2300 gas limit
             * imposed by `transfer`, making them unable to receive funds via
             * `transfer`. {sendValue} removes this limitation.
             *
             * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
             *
             * IMPORTANT: because control is transferred to `recipient`, care must be
             * taken to not create reentrancy vulnerabilities. Consider using
             * {ReentrancyGuard} or the
             * https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
             */
            function sendValue(address payable recipient, uint256 amount) internal {
                require(address(this).balance >= amount, "Address: insufficient balance");
                (bool success, ) = recipient.call{value: amount}("");
                require(success, "Address: unable to send value, recipient may have reverted");
            }
            /**
             * @dev Performs a Solidity function call using a low level `call`. A
             * plain `call` is an unsafe replacement for a function call: use this
             * function instead.
             *
             * If `target` reverts with a revert reason, it is bubbled up by this
             * function (like regular Solidity function calls).
             *
             * Returns the raw returned data. To convert to the expected return value,
             * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
             *
             * Requirements:
             *
             * - `target` must be a contract.
             * - calling `target` with `data` must not revert.
             *
             * _Available since v3.1._
             */
            function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                return functionCallWithValue(target, data, 0, "Address: low-level call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
             * `errorMessage` as a fallback revert reason when `target` reverts.
             *
             * _Available since v3.1._
             */
            function functionCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal returns (bytes memory) {
                return functionCallWithValue(target, data, 0, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but also transferring `value` wei to `target`.
             *
             * Requirements:
             *
             * - the calling contract must have an ETH balance of at least `value`.
             * - the called Solidity function must be `payable`.
             *
             * _Available since v3.1._
             */
            function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
            }
            /**
             * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
             * with `errorMessage` as a fallback revert reason when `target` reverts.
             *
             * _Available since v3.1._
             */
            function functionCallWithValue(
                address target,
                bytes memory data,
                uint256 value,
                string memory errorMessage
            ) internal returns (bytes memory) {
                require(address(this).balance >= value, "Address: insufficient balance for call");
                (bool success, bytes memory returndata) = target.call{value: value}(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but performing a static call.
             *
             * _Available since v3.3._
             */
            function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                return functionStaticCall(target, data, "Address: low-level static call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
             * but performing a static call.
             *
             * _Available since v3.3._
             */
            function functionStaticCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal view returns (bytes memory) {
                (bool success, bytes memory returndata) = target.staticcall(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but performing a delegate call.
             *
             * _Available since v3.4._
             */
            function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                return functionDelegateCall(target, data, "Address: low-level delegate call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
             * but performing a delegate call.
             *
             * _Available since v3.4._
             */
            function functionDelegateCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal returns (bytes memory) {
                (bool success, bytes memory returndata) = target.delegatecall(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
             * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
             *
             * _Available since v4.8._
             */
            function verifyCallResultFromTarget(
                address target,
                bool success,
                bytes memory returndata,
                string memory errorMessage
            ) internal view returns (bytes memory) {
                if (success) {
                    if (returndata.length == 0) {
                        // only check isContract if the call was successful and the return data is empty
                        // otherwise we already know that it was a contract
                        require(isContract(target), "Address: call to non-contract");
                    }
                    return returndata;
                } else {
                    _revert(returndata, errorMessage);
                }
            }
            /**
             * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
             * revert reason or using the provided one.
             *
             * _Available since v4.3._
             */
            function verifyCallResult(
                bool success,
                bytes memory returndata,
                string memory errorMessage
            ) internal pure returns (bytes memory) {
                if (success) {
                    return returndata;
                } else {
                    _revert(returndata, errorMessage);
                }
            }
            function _revert(bytes memory returndata, string memory errorMessage) private pure {
                // Look for revert reason and bubble it up if present
                if (returndata.length > 0) {
                    // The easiest way to bubble the revert reason is using memory via assembly
                    /// @solidity memory-safe-assembly
                    assembly {
                        let returndata_size := mload(returndata)
                        revert(add(32, returndata), returndata_size)
                    }
                } else {
                    revert(errorMessage);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SignedMath.sol)
        pragma solidity ^0.8.0;
        /**
         * @dev Standard signed math utilities missing in the Solidity language.
         */
        library SignedMath {
            /**
             * @dev Returns the largest of two signed numbers.
             */
            function max(int256 a, int256 b) internal pure returns (int256) {
                return a > b ? a : b;
            }
            /**
             * @dev Returns the smallest of two signed numbers.
             */
            function min(int256 a, int256 b) internal pure returns (int256) {
                return a < b ? a : b;
            }
            /**
             * @dev Returns the average of two signed numbers without overflow.
             * The result is rounded towards zero.
             */
            function average(int256 a, int256 b) internal pure returns (int256) {
                // Formula from the book "Hacker's Delight"
                int256 x = (a & b) + ((a ^ b) >> 1);
                return x + (int256(uint256(x) >> 255) & (a ^ b));
            }
            /**
             * @dev Returns the absolute unsigned value of a signed value.
             */
            function abs(int256 n) internal pure returns (uint256) {
                unchecked {
                    // must be unchecked in order to support `n = type(int256).min`
                    return uint256(n >= 0 ? n : -n);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        // OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
        pragma solidity ^0.8.1;
        /**
         * @dev Collection of functions related to the address type
         */
        library Address {
            /**
             * @dev Returns true if `account` is a contract.
             *
             * [IMPORTANT]
             * ====
             * It is unsafe to assume that an address for which this function returns
             * false is an externally-owned account (EOA) and not a contract.
             *
             * Among others, `isContract` will return false for the following
             * types of addresses:
             *
             *  - an externally-owned account
             *  - a contract in construction
             *  - an address where a contract will be created
             *  - an address where a contract lived, but was destroyed
             *
             * Furthermore, `isContract` will also return true if the target contract within
             * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
             * which only has an effect at the end of a transaction.
             * ====
             *
             * [IMPORTANT]
             * ====
             * You shouldn't rely on `isContract` to protect against flash loan attacks!
             *
             * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
             * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
             * constructor.
             * ====
             */
            function isContract(address account) internal view returns (bool) {
                // This method relies on extcodesize/address.code.length, which returns 0
                // for contracts in construction, since the code is only stored at the end
                // of the constructor execution.
                return account.code.length > 0;
            }
            /**
             * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
             * `recipient`, forwarding all available gas and reverting on errors.
             *
             * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
             * of certain opcodes, possibly making contracts go over the 2300 gas limit
             * imposed by `transfer`, making them unable to receive funds via
             * `transfer`. {sendValue} removes this limitation.
             *
             * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
             *
             * IMPORTANT: because control is transferred to `recipient`, care must be
             * taken to not create reentrancy vulnerabilities. Consider using
             * {ReentrancyGuard} or the
             * https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
             */
            function sendValue(address payable recipient, uint256 amount) internal {
                require(address(this).balance >= amount, "Address: insufficient balance");
                (bool success, ) = recipient.call{value: amount}("");
                require(success, "Address: unable to send value, recipient may have reverted");
            }
            /**
             * @dev Performs a Solidity function call using a low level `call`. A
             * plain `call` is an unsafe replacement for a function call: use this
             * function instead.
             *
             * If `target` reverts with a revert reason, it is bubbled up by this
             * function (like regular Solidity function calls).
             *
             * Returns the raw returned data. To convert to the expected return value,
             * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
             *
             * Requirements:
             *
             * - `target` must be a contract.
             * - calling `target` with `data` must not revert.
             *
             * _Available since v3.1._
             */
            function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                return functionCallWithValue(target, data, 0, "Address: low-level call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
             * `errorMessage` as a fallback revert reason when `target` reverts.
             *
             * _Available since v3.1._
             */
            function functionCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal returns (bytes memory) {
                return functionCallWithValue(target, data, 0, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but also transferring `value` wei to `target`.
             *
             * Requirements:
             *
             * - the calling contract must have an ETH balance of at least `value`.
             * - the called Solidity function must be `payable`.
             *
             * _Available since v3.1._
             */
            function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
            }
            /**
             * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
             * with `errorMessage` as a fallback revert reason when `target` reverts.
             *
             * _Available since v3.1._
             */
            function functionCallWithValue(
                address target,
                bytes memory data,
                uint256 value,
                string memory errorMessage
            ) internal returns (bytes memory) {
                require(address(this).balance >= value, "Address: insufficient balance for call");
                (bool success, bytes memory returndata) = target.call{value: value}(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but performing a static call.
             *
             * _Available since v3.3._
             */
            function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                return functionStaticCall(target, data, "Address: low-level static call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
             * but performing a static call.
             *
             * _Available since v3.3._
             */
            function functionStaticCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal view returns (bytes memory) {
                (bool success, bytes memory returndata) = target.staticcall(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
             * but performing a delegate call.
             *
             * _Available since v3.4._
             */
            function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                return functionDelegateCall(target, data, "Address: low-level delegate call failed");
            }
            /**
             * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
             * but performing a delegate call.
             *
             * _Available since v3.4._
             */
            function functionDelegateCall(
                address target,
                bytes memory data,
                string memory errorMessage
            ) internal returns (bytes memory) {
                (bool success, bytes memory returndata) = target.delegatecall(data);
                return verifyCallResultFromTarget(target, success, returndata, errorMessage);
            }
            /**
             * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
             * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
             *
             * _Available since v4.8._
             */
            function verifyCallResultFromTarget(
                address target,
                bool success,
                bytes memory returndata,
                string memory errorMessage
            ) internal view returns (bytes memory) {
                if (success) {
                    if (returndata.length == 0) {
                        // only check isContract if the call was successful and the return data is empty
                        // otherwise we already know that it was a contract
                        require(isContract(target), "Address: call to non-contract");
                    }
                    return returndata;
                } else {
                    _revert(returndata, errorMessage);
                }
            }
            /**
             * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
             * revert reason or using the provided one.
             *
             * _Available since v4.3._
             */
            function verifyCallResult(
                bool success,
                bytes memory returndata,
                string memory errorMessage
            ) internal pure returns (bytes memory) {
                if (success) {
                    return returndata;
                } else {
                    _revert(returndata, errorMessage);
                }
            }
            function _revert(bytes memory returndata, string memory errorMessage) private pure {
                // Look for revert reason and bubble it up if present
                if (returndata.length > 0) {
                    // The easiest way to bubble the revert reason is using memory via assembly
                    /// @solidity memory-safe-assembly
                    assembly {
                        let returndata_size := mload(returndata)
                        revert(add(32, returndata), returndata_size)
                    }
                } else {
                    revert(errorMessage);
                }
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity >=0.8.0;
        /// @notice Arithmetic library with operations for fixed-point numbers.
        /// @author Solmate (https://github.com/Rari-Capital/solmate/blob/main/src/utils/FixedPointMathLib.sol)
        library FixedPointMathLib {
            /*//////////////////////////////////////////////////////////////
                            SIMPLIFIED FIXED POINT OPERATIONS
            //////////////////////////////////////////////////////////////*/
            uint256 internal constant WAD = 1e18; // The scalar of ETH and most ERC20s.
            function mulWadDown(uint256 x, uint256 y) internal pure returns (uint256) {
                return mulDivDown(x, y, WAD); // Equivalent to (x * y) / WAD rounded down.
            }
            function mulWadUp(uint256 x, uint256 y) internal pure returns (uint256) {
                return mulDivUp(x, y, WAD); // Equivalent to (x * y) / WAD rounded up.
            }
            function divWadDown(uint256 x, uint256 y) internal pure returns (uint256) {
                return mulDivDown(x, WAD, y); // Equivalent to (x * WAD) / y rounded down.
            }
            function divWadUp(uint256 x, uint256 y) internal pure returns (uint256) {
                return mulDivUp(x, WAD, y); // Equivalent to (x * WAD) / y rounded up.
            }
            function powWad(int256 x, int256 y) internal pure returns (int256) {
                // Equivalent to x to the power of y because x ** y = (e ** ln(x)) ** y = e ** (ln(x) * y)
                return expWad((lnWad(x) * y) / int256(WAD)); // Using ln(x) means x must be greater than 0.
            }
            function expWad(int256 x) internal pure returns (int256 r) {
                unchecked {
                    // When the result is < 0.5 we return zero. This happens when
                    // x <= floor(log(0.5e18) * 1e18) ~ -42e18
                    if (x <= -42139678854452767551) return 0;
                    // When the result is > (2**255 - 1) / 1e18 we can not represent it as an
                    // int. This happens when x >= floor(log((2**255 - 1) / 1e18) * 1e18) ~ 135.
                    if (x >= 135305999368893231589) revert("EXP_OVERFLOW");
                    // x is now in the range (-42, 136) * 1e18. Convert to (-42, 136) * 2**96
                    // for more intermediate precision and a binary basis. This base conversion
                    // is a multiplication by 1e18 / 2**96 = 5**18 / 2**78.
                    x = (x << 78) / 5**18;
                    // Reduce range of x to (-½ ln 2, ½ ln 2) * 2**96 by factoring out powers
                    // of two such that exp(x) = exp(x') * 2**k, where k is an integer.
                    // Solving this gives k = round(x / log(2)) and x' = x - k * log(2).
                    int256 k = ((x << 96) / 54916777467707473351141471128 + 2**95) >> 96;
                    x = x - k * 54916777467707473351141471128;
                    // k is in the range [-61, 195].
                    // Evaluate using a (6, 7)-term rational approximation.
                    // p is made monic, we'll multiply by a scale factor later.
                    int256 y = x + 1346386616545796478920950773328;
                    y = ((y * x) >> 96) + 57155421227552351082224309758442;
                    int256 p = y + x - 94201549194550492254356042504812;
                    p = ((p * y) >> 96) + 28719021644029726153956944680412240;
                    p = p * x + (4385272521454847904659076985693276 << 96);
                    // We leave p in 2**192 basis so we don't need to scale it back up for the division.
                    int256 q = x - 2855989394907223263936484059900;
                    q = ((q * x) >> 96) + 50020603652535783019961831881945;
                    q = ((q * x) >> 96) - 533845033583426703283633433725380;
                    q = ((q * x) >> 96) + 3604857256930695427073651918091429;
                    q = ((q * x) >> 96) - 14423608567350463180887372962807573;
                    q = ((q * x) >> 96) + 26449188498355588339934803723976023;
                    assembly {
                        // Div in assembly because solidity adds a zero check despite the unchecked.
                        // The q polynomial won't have zeros in the domain as all its roots are complex.
                        // No scaling is necessary because p is already 2**96 too large.
                        r := sdiv(p, q)
                    }
                    // r should be in the range (0.09, 0.25) * 2**96.
                    // We now need to multiply r by:
                    // * the scale factor s = ~6.031367120.
                    // * the 2**k factor from the range reduction.
                    // * the 1e18 / 2**96 factor for base conversion.
                    // We do this all at once, with an intermediate result in 2**213
                    // basis, so the final right shift is always by a positive amount.
                    r = int256((uint256(r) * 3822833074963236453042738258902158003155416615667) >> uint256(195 - k));
                }
            }
            function lnWad(int256 x) internal pure returns (int256 r) {
                unchecked {
                    require(x > 0, "UNDEFINED");
                    // We want to convert x from 10**18 fixed point to 2**96 fixed point.
                    // We do this by multiplying by 2**96 / 10**18. But since
                    // ln(x * C) = ln(x) + ln(C), we can simply do nothing here
                    // and add ln(2**96 / 10**18) at the end.
                    // Reduce range of x to (1, 2) * 2**96
                    // ln(2^k * x) = k * ln(2) + ln(x)
                    int256 k = int256(log2(uint256(x))) - 96;
                    x <<= uint256(159 - k);
                    x = int256(uint256(x) >> 159);
                    // Evaluate using a (8, 8)-term rational approximation.
                    // p is made monic, we will multiply by a scale factor later.
                    int256 p = x + 3273285459638523848632254066296;
                    p = ((p * x) >> 96) + 24828157081833163892658089445524;
                    p = ((p * x) >> 96) + 43456485725739037958740375743393;
                    p = ((p * x) >> 96) - 11111509109440967052023855526967;
                    p = ((p * x) >> 96) - 45023709667254063763336534515857;
                    p = ((p * x) >> 96) - 14706773417378608786704636184526;
                    p = p * x - (795164235651350426258249787498 << 96);
                    // We leave p in 2**192 basis so we don't need to scale it back up for the division.
                    // q is monic by convention.
                    int256 q = x + 5573035233440673466300451813936;
                    q = ((q * x) >> 96) + 71694874799317883764090561454958;
                    q = ((q * x) >> 96) + 283447036172924575727196451306956;
                    q = ((q * x) >> 96) + 401686690394027663651624208769553;
                    q = ((q * x) >> 96) + 204048457590392012362485061816622;
                    q = ((q * x) >> 96) + 31853899698501571402653359427138;
                    q = ((q * x) >> 96) + 909429971244387300277376558375;
                    assembly {
                        // Div in assembly because solidity adds a zero check despite the unchecked.
                        // The q polynomial is known not to have zeros in the domain.
                        // No scaling required because p is already 2**96 too large.
                        r := sdiv(p, q)
                    }
                    // r is in the range (0, 0.125) * 2**96
                    // Finalization, we need to:
                    // * multiply by the scale factor s = 5.549…
                    // * add ln(2**96 / 10**18)
                    // * add k * ln(2)
                    // * multiply by 10**18 / 2**96 = 5**18 >> 78
                    // mul s * 5e18 * 2**96, base is now 5**18 * 2**192
                    r *= 1677202110996718588342820967067443963516166;
                    // add ln(2) * k * 5e18 * 2**192
                    r += 16597577552685614221487285958193947469193820559219878177908093499208371 * k;
                    // add ln(2**96 / 10**18) * 5e18 * 2**192
                    r += 600920179829731861736702779321621459595472258049074101567377883020018308;
                    // base conversion: mul 2**18 / 2**192
                    r >>= 174;
                }
            }
            /*//////////////////////////////////////////////////////////////
                            LOW LEVEL FIXED POINT OPERATIONS
            //////////////////////////////////////////////////////////////*/
            function mulDivDown(
                uint256 x,
                uint256 y,
                uint256 denominator
            ) internal pure returns (uint256 z) {
                assembly {
                    // Store x * y in z for now.
                    z := mul(x, y)
                    // Equivalent to require(denominator != 0 && (x == 0 || (x * y) / x == y))
                    if iszero(and(iszero(iszero(denominator)), or(iszero(x), eq(div(z, x), y)))) {
                        revert(0, 0)
                    }
                    // Divide z by the denominator.
                    z := div(z, denominator)
                }
            }
            function mulDivUp(
                uint256 x,
                uint256 y,
                uint256 denominator
            ) internal pure returns (uint256 z) {
                assembly {
                    // Store x * y in z for now.
                    z := mul(x, y)
                    // Equivalent to require(denominator != 0 && (x == 0 || (x * y) / x == y))
                    if iszero(and(iszero(iszero(denominator)), or(iszero(x), eq(div(z, x), y)))) {
                        revert(0, 0)
                    }
                    // First, divide z - 1 by the denominator and add 1.
                    // We allow z - 1 to underflow if z is 0, because we multiply the
                    // end result by 0 if z is zero, ensuring we return 0 if z is zero.
                    z := mul(iszero(iszero(z)), add(div(sub(z, 1), denominator), 1))
                }
            }
            function rpow(
                uint256 x,
                uint256 n,
                uint256 scalar
            ) internal pure returns (uint256 z) {
                assembly {
                    switch x
                    case 0 {
                        switch n
                        case 0 {
                            // 0 ** 0 = 1
                            z := scalar
                        }
                        default {
                            // 0 ** n = 0
                            z := 0
                        }
                    }
                    default {
                        switch mod(n, 2)
                        case 0 {
                            // If n is even, store scalar in z for now.
                            z := scalar
                        }
                        default {
                            // If n is odd, store x in z for now.
                            z := x
                        }
                        // Shifting right by 1 is like dividing by 2.
                        let half := shr(1, scalar)
                        for {
                            // Shift n right by 1 before looping to halve it.
                            n := shr(1, n)
                        } n {
                            // Shift n right by 1 each iteration to halve it.
                            n := shr(1, n)
                        } {
                            // Revert immediately if x ** 2 would overflow.
                            // Equivalent to iszero(eq(div(xx, x), x)) here.
                            if shr(128, x) {
                                revert(0, 0)
                            }
                            // Store x squared.
                            let xx := mul(x, x)
                            // Round to the nearest number.
                            let xxRound := add(xx, half)
                            // Revert if xx + half overflowed.
                            if lt(xxRound, xx) {
                                revert(0, 0)
                            }
                            // Set x to scaled xxRound.
                            x := div(xxRound, scalar)
                            // If n is even:
                            if mod(n, 2) {
                                // Compute z * x.
                                let zx := mul(z, x)
                                // If z * x overflowed:
                                if iszero(eq(div(zx, x), z)) {
                                    // Revert if x is non-zero.
                                    if iszero(iszero(x)) {
                                        revert(0, 0)
                                    }
                                }
                                // Round to the nearest number.
                                let zxRound := add(zx, half)
                                // Revert if zx + half overflowed.
                                if lt(zxRound, zx) {
                                    revert(0, 0)
                                }
                                // Return properly scaled zxRound.
                                z := div(zxRound, scalar)
                            }
                        }
                    }
                }
            }
            /*//////////////////////////////////////////////////////////////
                                GENERAL NUMBER UTILITIES
            //////////////////////////////////////////////////////////////*/
            function sqrt(uint256 x) internal pure returns (uint256 z) {
                assembly {
                    let y := x // We start y at x, which will help us make our initial estimate.
                    z := 181 // The "correct" value is 1, but this saves a multiplication later.
                    // This segment is to get a reasonable initial estimate for the Babylonian method. With a bad
                    // start, the correct # of bits increases ~linearly each iteration instead of ~quadratically.
                    // We check y >= 2^(k + 8) but shift right by k bits
                    // each branch to ensure that if x >= 256, then y >= 256.
                    if iszero(lt(y, 0x10000000000000000000000000000000000)) {
                        y := shr(128, y)
                        z := shl(64, z)
                    }
                    if iszero(lt(y, 0x1000000000000000000)) {
                        y := shr(64, y)
                        z := shl(32, z)
                    }
                    if iszero(lt(y, 0x10000000000)) {
                        y := shr(32, y)
                        z := shl(16, z)
                    }
                    if iszero(lt(y, 0x1000000)) {
                        y := shr(16, y)
                        z := shl(8, z)
                    }
                    // Goal was to get z*z*y within a small factor of x. More iterations could
                    // get y in a tighter range. Currently, we will have y in [256, 256*2^16).
                    // We ensured y >= 256 so that the relative difference between y and y+1 is small.
                    // That's not possible if x < 256 but we can just verify those cases exhaustively.
                    // Now, z*z*y <= x < z*z*(y+1), and y <= 2^(16+8), and either y >= 256, or x < 256.
                    // Correctness can be checked exhaustively for x < 256, so we assume y >= 256.
                    // Then z*sqrt(y) is within sqrt(257)/sqrt(256) of sqrt(x), or about 20bps.
                    // For s in the range [1/256, 256], the estimate f(s) = (181/1024) * (s+1) is in the range
                    // (1/2.84 * sqrt(s), 2.84 * sqrt(s)), with largest error when s = 1 and when s = 256 or 1/256.
                    // Since y is in [256, 256*2^16), let a = y/65536, so that a is in [1/256, 256). Then we can estimate
                    // sqrt(y) using sqrt(65536) * 181/1024 * (a + 1) = 181/4 * (y + 65536)/65536 = 181 * (y + 65536)/2^18.
                    // There is no overflow risk here since y < 2^136 after the first branch above.
                    z := shr(18, mul(z, add(y, 65536))) // A mul() is saved from starting z at 181.
                    // Given the worst case multiplicative error of 2.84 above, 7 iterations should be enough.
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    z := shr(1, add(z, div(x, z)))
                    // If x+1 is a perfect square, the Babylonian method cycles between
                    // floor(sqrt(x)) and ceil(sqrt(x)). This statement ensures we return floor.
                    // See: https://en.wikipedia.org/wiki/Integer_square_root#Using_only_integer_division
                    // Since the ceil is rare, we save gas on the assignment and repeat division in the rare case.
                    // If you don't care whether the floor or ceil square root is returned, you can remove this statement.
                    z := sub(z, lt(div(x, z), z))
                }
            }
            function log2(uint256 x) internal pure returns (uint256 r) {
                require(x > 0, "UNDEFINED");
                assembly {
                    r := shl(7, lt(0xffffffffffffffffffffffffffffffff, x))
                    r := or(r, shl(6, lt(0xffffffffffffffff, shr(r, x))))
                    r := or(r, shl(5, lt(0xffffffff, shr(r, x))))
                    r := or(r, shl(4, lt(0xffff, shr(r, x))))
                    r := or(r, shl(3, lt(0xff, shr(r, x))))
                    r := or(r, shl(2, lt(0xf, shr(r, x))))
                    r := or(r, shl(1, lt(0x3, shr(r, x))))
                    r := or(r, lt(0x1, shr(r, x)))
                }
            }
        }
        // SPDX-License-Identifier: MIT
        pragma solidity 0.8.15;
        /**
         * @title SafeCall
         * @notice Perform low level safe calls
         */
        library SafeCall {
            /**
             * @notice Perform a low level call without copying any returndata
             *
             * @param _target   Address to call
             * @param _gas      Amount of gas to pass to the call
             * @param _value    Amount of value to pass to the call
             * @param _calldata Calldata to pass to the call
             */
            function call(
                address _target,
                uint256 _gas,
                uint256 _value,
                bytes memory _calldata
            ) internal returns (bool) {
                bool _success;
                assembly {
                    _success := call(
                        _gas, // gas
                        _target, // recipient
                        _value, // ether value
                        add(_calldata, 32), // inloc
                        mload(_calldata), // inlen
                        0, // outloc
                        0 // outlen
                    )
                }
                return _success;
            }
            /**
             * @notice Helper function to determine if there is sufficient gas remaining within the context
             *         to guarantee that the minimum gas requirement for a call will be met as well as
             *         optionally reserving a specified amount of gas for after the call has concluded.
             *
             * @param _minGas      The minimum amount of gas that may be passed to the target context.
             * @param _reservedGas Optional amount of gas to reserve for the caller after the execution
             *                     of the target context.
             *
             * @return `true` if there is enough gas remaining to safely supply `_minGas` to the target
             *         context as well as reserve `_reservedGas` for the caller after the execution of
             *         the target context.
             *
             * @dev !!!!! FOOTGUN ALERT !!!!!
             *      1.) The 40_000 base buffer is to account for the worst case of the dynamic cost of the
             *          `CALL` opcode's `address_access_cost`, `positive_value_cost`, and
             *          `value_to_empty_account_cost` factors with an added buffer of 5,700 gas. It is
             *          still possible to self-rekt by initiating a withdrawal with a minimum gas limit
             *          that does not account for the `memory_expansion_cost` & `code_execution_cost`
             *          factors of the dynamic cost of the `CALL` opcode.
             *      2.) This function should *directly* precede the external call if possible. There is an
             *          added buffer to account for gas consumed between this check and the call, but it
             *          is only 5,700 gas.
             *      3.) Because EIP-150 ensures that a maximum of 63/64ths of the remaining gas in the call
             *          frame may be passed to a subcontext, we need to ensure that the gas will not be
             *          truncated.
             *      4.) Use wisely. This function is not a silver bullet.
             */
            function hasMinGas(uint256 _minGas, uint256 _reservedGas) internal view returns (bool) {
                bool _hasMinGas;
                assembly {
                    // Equation: gas × 63 ≥ minGas × 64 + 63(40_000 + reservedGas)
                    _hasMinGas := iszero(
                        lt(mul(gas(), 63), add(mul(_minGas, 64), mul(add(40000, _reservedGas), 63)))
                    )
                }
                return _hasMinGas;
            }
            /**
             * @notice Perform a low level call without copying any returndata. This function
             *         will revert if the call cannot be performed with the specified minimum
             *         gas.
             *
             * @param _target   Address to call
             * @param _minGas   The minimum amount of gas that may be passed to the call
             * @param _value    Amount of value to pass to the call
             * @param _calldata Calldata to pass to the call
             */
            function callWithMinGas(
                address _target,
                uint256 _minGas,
                uint256 _value,
                bytes memory _calldata
            ) internal returns (bool) {
                bool _success;
                bool _hasMinGas = hasMinGas(_minGas, 0);
                assembly {
                    // Assertion: gasleft() >= (_minGas * 64) / 63 + 40_000
                    if iszero(_hasMinGas) {
                        // Store the "Error(string)" selector in scratch space.
                        mstore(0, 0x08c379a0)
                        // Store the pointer to the string length in scratch space.
                        mstore(32, 32)
                        // Store the string.
                        //
                        // SAFETY:
                        // - We pad the beginning of the string with two zero bytes as well as the
                        // length (24) to ensure that we override the free memory pointer at offset
                        // 0x40. This is necessary because the free memory pointer is likely to
                        // be greater than 1 byte when this function is called, but it is incredibly
                        // unlikely that it will be greater than 3 bytes. As for the data within
                        // 0x60, it is ensured that it is 0 due to 0x60 being the zero offset.
                        // - It's fine to clobber the free memory pointer, we're reverting.
                        mstore(88, 0x0000185361666543616c6c3a204e6f7420656e6f75676820676173)
                        // Revert with 'Error("SafeCall: Not enough gas")'
                        revert(28, 100)
                    }
                    // The call will be supplied at least ((_minGas * 64) / 63 + 40_000 - 49) gas due to the
                    // above assertion. This ensures that, in all circumstances (except for when the
                    // `_minGas` does not account for the `memory_expansion_cost` and `code_execution_cost`
                    // factors of the dynamic cost of the `CALL` opcode), the call will receive at least
                    // the minimum amount of gas specified.
                    _success := call(
                        gas(), // gas
                        _target, // recipient
                        _value, // ether value
                        add(_calldata, 32), // inloc
                        mload(_calldata), // inlen
                        0x00, // outloc
                        0x00 // outlen
                    )
                }
                return _success;
            }
        }