pragma solidity ^0.5.16;
pragma experimental ABIEncoderV2;

contract Comp {
    /// @notice EIP-20 token name for this token
    string public constant name = "Compound";

    /// @notice EIP-20 token symbol for this token
    string public constant symbol = "COMP";

    /// @notice EIP-20 token decimals for this token
    uint8 public constant decimals = 18;

    /// @notice Total number of tokens in circulation
    uint public constant totalSupply = 10000000e18; // 10 million Comp

    /// @notice Allowance amounts on behalf of others
    mapping (address => mapping (address => uint96)) internal allowances;

    /// @notice Official record of token balances for each account
    mapping (address => uint96) internal balances;

    /// @notice A record of each accounts delegate
    mapping (address => address) public delegates;

    /// @notice A checkpoint for marking number of votes from a given block
    struct Checkpoint {
        uint32 fromBlock;
        uint96 votes;
    }

    /// @notice A record of votes checkpoints for each account, by index
    mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;

    /// @notice The number of checkpoints for each account
    mapping (address => uint32) public numCheckpoints;

    /// @notice The EIP-712 typehash for the contract's domain
    bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");

    /// @notice The EIP-712 typehash for the delegation struct used by the contract
    bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");

    /// @notice A record of states for signing / validating signatures
    mapping (address => uint) public nonces;

    /// @notice An event thats emitted when an account changes its delegate
    event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);

    /// @notice An event thats emitted when a delegate account's vote balance changes
    event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);

    /// @notice The standard EIP-20 transfer event
    event Transfer(address indexed from, address indexed to, uint256 amount);

    /// @notice The standard EIP-20 approval event
    event Approval(address indexed owner, address indexed spender, uint256 amount);

    /**
     * @notice Construct a new Comp token
     * @param account The initial account to grant all the tokens
     */
    constructor(address account) public {
        balances[account] = uint96(totalSupply);
        emit Transfer(address(0), account, totalSupply);
    }

    /**
     * @notice Get the number of tokens `spender` is approved to spend on behalf of `account`
     * @param account The address of the account holding the funds
     * @param spender The address of the account spending the funds
     * @return The number of tokens approved
     */
    function allowance(address account, address spender) external view returns (uint) {
        return allowances[account][spender];
    }

    /**
     * @notice Approve `spender` to transfer up to `amount` from `src`
     * @dev This will overwrite the approval amount for `spender`
     *  and is subject to issues noted [here](https://eips.ethereum.org/EIPS/eip-20#approve)
     * @param spender The address of the account which may transfer tokens
     * @param rawAmount The number of tokens that are approved (2^256-1 means infinite)
     * @return Whether or not the approval succeeded
     */
    function approve(address spender, uint rawAmount) external returns (bool) {
        uint96 amount;
        if (rawAmount == uint(-1)) {
            amount = uint96(-1);
        } else {
            amount = safe96(rawAmount, "Comp::approve: amount exceeds 96 bits");
        }

        allowances[msg.sender][spender] = amount;

        emit Approval(msg.sender, spender, amount);
        return true;
    }

    /**
     * @notice Get the number of tokens held by the `account`
     * @param account The address of the account to get the balance of
     * @return The number of tokens held
     */
    function balanceOf(address account) external view returns (uint) {
        return balances[account];
    }

    /**
     * @notice Transfer `amount` tokens from `msg.sender` to `dst`
     * @param dst The address of the destination account
     * @param rawAmount The number of tokens to transfer
     * @return Whether or not the transfer succeeded
     */
    function transfer(address dst, uint rawAmount) external returns (bool) {
        uint96 amount = safe96(rawAmount, "Comp::transfer: amount exceeds 96 bits");
        _transferTokens(msg.sender, dst, amount);
        return true;
    }

    /**
     * @notice Transfer `amount` tokens from `src` to `dst`
     * @param src The address of the source account
     * @param dst The address of the destination account
     * @param rawAmount The number of tokens to transfer
     * @return Whether or not the transfer succeeded
     */
    function transferFrom(address src, address dst, uint rawAmount) external returns (bool) {
        address spender = msg.sender;
        uint96 spenderAllowance = allowances[src][spender];
        uint96 amount = safe96(rawAmount, "Comp::approve: amount exceeds 96 bits");

        if (spender != src && spenderAllowance != uint96(-1)) {
            uint96 newAllowance = sub96(spenderAllowance, amount, "Comp::transferFrom: transfer amount exceeds spender allowance");
            allowances[src][spender] = newAllowance;

            emit Approval(src, spender, newAllowance);
        }

        _transferTokens(src, dst, amount);
        return true;
    }

    /**
     * @notice Delegate votes from `msg.sender` to `delegatee`
     * @param delegatee The address to delegate votes to
     */
    function delegate(address delegatee) public {
        return _delegate(msg.sender, delegatee);
    }

    /**
     * @notice Delegates votes from signatory to `delegatee`
     * @param delegatee The address to delegate votes to
     * @param nonce The contract state required to match the signature
     * @param expiry The time at which to expire the signature
     * @param v The recovery byte of the signature
     * @param r Half of the ECDSA signature pair
     * @param s Half of the ECDSA signature pair
     */
    function delegateBySig(address delegatee, uint nonce, uint expiry, uint8 v, bytes32 r, bytes32 s) public {
        bytes32 domainSeparator = keccak256(abi.encode(DOMAIN_TYPEHASH, keccak256(bytes(name)), getChainId(), address(this)));
        bytes32 structHash = keccak256(abi.encode(DELEGATION_TYPEHASH, delegatee, nonce, expiry));
        bytes32 digest = keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
        address signatory = ecrecover(digest, v, r, s);
        require(signatory != address(0), "Comp::delegateBySig: invalid signature");
        require(nonce == nonces[signatory]++, "Comp::delegateBySig: invalid nonce");
        require(now <= expiry, "Comp::delegateBySig: signature expired");
        return _delegate(signatory, delegatee);
    }

    /**
     * @notice Gets the current votes balance for `account`
     * @param account The address to get votes balance
     * @return The number of current votes for `account`
     */
    function getCurrentVotes(address account) external view returns (uint96) {
        uint32 nCheckpoints = numCheckpoints[account];
        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
    }

    /**
     * @notice Determine the prior number of votes for an account as of a block number
     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.
     * @param account The address of the account to check
     * @param blockNumber The block number to get the vote balance at
     * @return The number of votes the account had as of the given block
     */
    function getPriorVotes(address account, uint blockNumber) public view returns (uint96) {
        require(blockNumber < block.number, "Comp::getPriorVotes: not yet determined");

        uint32 nCheckpoints = numCheckpoints[account];
        if (nCheckpoints == 0) {
            return 0;
        }

        // First check most recent balance
        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
            return checkpoints[account][nCheckpoints - 1].votes;
        }

        // Next check implicit zero balance
        if (checkpoints[account][0].fromBlock > blockNumber) {
            return 0;
        }

        uint32 lower = 0;
        uint32 upper = nCheckpoints - 1;
        while (upper > lower) {
            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
            Checkpoint memory cp = checkpoints[account][center];
            if (cp.fromBlock == blockNumber) {
                return cp.votes;
            } else if (cp.fromBlock < blockNumber) {
                lower = center;
            } else {
                upper = center - 1;
            }
        }
        return checkpoints[account][lower].votes;
    }

    function _delegate(address delegator, address delegatee) internal {
        address currentDelegate = delegates[delegator];
        uint96 delegatorBalance = balances[delegator];
        delegates[delegator] = delegatee;

        emit DelegateChanged(delegator, currentDelegate, delegatee);

        _moveDelegates(currentDelegate, delegatee, delegatorBalance);
    }

    function _transferTokens(address src, address dst, uint96 amount) internal {
        require(src != address(0), "Comp::_transferTokens: cannot transfer from the zero address");
        require(dst != address(0), "Comp::_transferTokens: cannot transfer to the zero address");

        balances[src] = sub96(balances[src], amount, "Comp::_transferTokens: transfer amount exceeds balance");
        balances[dst] = add96(balances[dst], amount, "Comp::_transferTokens: transfer amount overflows");
        emit Transfer(src, dst, amount);

        _moveDelegates(delegates[src], delegates[dst], amount);
    }

    function _moveDelegates(address srcRep, address dstRep, uint96 amount) internal {
        if (srcRep != dstRep && amount > 0) {
            if (srcRep != address(0)) {
                uint32 srcRepNum = numCheckpoints[srcRep];
                uint96 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;
                uint96 srcRepNew = sub96(srcRepOld, amount, "Comp::_moveVotes: vote amount underflows");
                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
            }

            if (dstRep != address(0)) {
                uint32 dstRepNum = numCheckpoints[dstRep];
                uint96 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;
                uint96 dstRepNew = add96(dstRepOld, amount, "Comp::_moveVotes: vote amount overflows");
                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
            }
        }
    }

    function _writeCheckpoint(address delegatee, uint32 nCheckpoints, uint96 oldVotes, uint96 newVotes) internal {
      uint32 blockNumber = safe32(block.number, "Comp::_writeCheckpoint: block number exceeds 32 bits");

      if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {
          checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
      } else {
          checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);
          numCheckpoints[delegatee] = nCheckpoints + 1;
      }

      emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
    }

    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {
        require(n < 2**32, errorMessage);
        return uint32(n);
    }

    function safe96(uint n, string memory errorMessage) internal pure returns (uint96) {
        require(n < 2**96, errorMessage);
        return uint96(n);
    }

    function add96(uint96 a, uint96 b, string memory errorMessage) internal pure returns (uint96) {
        uint96 c = a + b;
        require(c >= a, errorMessage);
        return c;
    }

    function sub96(uint96 a, uint96 b, string memory errorMessage) internal pure returns (uint96) {
        require(b <= a, errorMessage);
        return a - b;
    }

    function getChainId() internal pure returns (uint) {
        uint256 chainId;
        assembly { chainId := chainid() }
        return chainId;
    }
}

pragma solidity ^0.4.14;

/**
 * Contract that exposes the needed erc20 token functions
 */

contract ERC20Interface {
  // Send _value amount of tokens to address _to
  function transfer(address _to, uint256 _value) returns (bool success);
  // Get the account balance of another account with address _owner
  function balanceOf(address _owner) constant returns (uint256 balance);
}

/**
 * Contract that will forward any incoming Ether to its creator
 */
contract Forwarder {
  // Address to which any funds sent to this contract will be forwarded
  address public parentAddress;
  event ForwarderDeposited(address from, uint value, bytes data);

  event TokensFlushed(
    address tokenContractAddress, // The contract address of the token
    uint value // Amount of token sent
  );

  /**
   * Create the contract, and set the destination address to that of the creator
   */
  function Forwarder() {
    parentAddress = msg.sender;
  }

  /**
   * Modifier that will execute internal code block only if the sender is a parent of the forwarder contract
   */
  modifier onlyParent {
    if (msg.sender != parentAddress) {
      throw;
    }
    _;
  }

  /**
   * Default function; Gets called when Ether is deposited, and forwards it to the destination address
   */
  function() payable {
    if (!parentAddress.call.value(msg.value)(msg.data))
      throw;
    // Fire off the deposited event if we can forward it  
    ForwarderDeposited(msg.sender, msg.value, msg.data);
  }

  /**
   * Execute a token transfer of the full balance from the forwarder token to the main wallet contract
   * @param tokenContractAddress the address of the erc20 token contract
   */
  function flushTokens(address tokenContractAddress) onlyParent {
    ERC20Interface instance = ERC20Interface(tokenContractAddress);
    var forwarderAddress = address(this);
    var forwarderBalance = instance.balanceOf(forwarderAddress);
    if (forwarderBalance == 0) {
      return;
    }
    if (!instance.transfer(parentAddress, forwarderBalance)) {
      throw;
    }
    TokensFlushed(tokenContractAddress, forwarderBalance);
  }

  /**
   * It is possible that funds were sent to this address before the contract was deployed.
   * We can flush those funds to the destination address.
   */
  function flush() {
    if (!parentAddress.call.value(this.balance)())
      throw;
  }
}

/**
 * Basic multi-signer wallet designed for use in a co-signing environment where 2 signatures are required to move funds.
 * Typically used in a 2-of-3 signing configuration. Uses ecrecover to allow for 2 signatures in a single transaction.
 */
contract WalletSimple {
  // Events
  event Deposited(address from, uint value, bytes data);
  event SafeModeActivated(address msgSender);
  event Transacted(
    address msgSender, // Address of the sender of the message initiating the transaction
    address otherSigner, // Address of the signer (second signature) used to initiate the transaction
    bytes32 operation, // Operation hash (sha3 of toAddress, value, data, expireTime, sequenceId)
    address toAddress, // The address the transaction was sent to
    uint value, // Amount of Wei sent to the address
    bytes data // Data sent when invoking the transaction
  );
  event TokenTransacted(
    address msgSender, // Address of the sender of the message initiating the transaction
    address otherSigner, // Address of the signer (second signature) used to initiate the transaction
    bytes32 operation, // Operation hash (sha3 of toAddress, value, tokenContractAddress, expireTime, sequenceId)
    address toAddress, // The address the transaction was sent to
    uint value, // Amount of token sent
    address tokenContractAddress // The contract address of the token
  );

  // Public fields
  address[] public signers; // The addresses that can co-sign transactions on the wallet
  bool public safeMode = false; // When active, wallet may only send to signer addresses

  // Internal fields
  uint constant SEQUENCE_ID_WINDOW_SIZE = 10;
  uint[10] recentSequenceIds;

  /**
   * Modifier that will execute internal code block only if the sender is an authorized signer on this wallet
   */
  modifier onlysigner {
    if (!isSigner(msg.sender)) {
      throw;
    }
    _;
  }

  /**
   * Set up a simple multi-sig wallet by specifying the signers allowed to be used on this wallet.
   * 2 signers will be required to send a transaction from this wallet.
   * Note: The sender is NOT automatically added to the list of signers.
   * Signers CANNOT be changed once they are set
   *
   * @param allowedSigners An array of signers on the wallet
   */
  function WalletSimple(address[] allowedSigners) {
    if (allowedSigners.length != 3) {
      // Invalid number of signers
      throw;
    }
    signers = allowedSigners;
  }

  /**
   * Gets called when a transaction is received without calling a method
   */
  function() payable {
    if (msg.value > 0) {
      // Fire deposited event if we are receiving funds
      Deposited(msg.sender, msg.value, msg.data);
    }
  }

  /**
   * Create a new contract (and also address) that forwards funds to this contract
   * returns address of newly created forwarder address
   */
  function createForwarder() onlysigner returns (address) {
    return new Forwarder();
  }

  /**
   * Execute a multi-signature transaction from this wallet using 2 signers: one from msg.sender and the other from ecrecover.
   * The signature is a signed form (using eth.sign) of tightly packed toAddress, value, data, expireTime and sequenceId
   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.
   *
   * @param toAddress the destination address to send an outgoing transaction
   * @param value the amount in Wei to be sent
   * @param data the data to send to the toAddress when invoking the transaction
   * @param expireTime the number of seconds since 1970 for which this transaction is valid
   * @param sequenceId the unique sequence id obtainable from getNextSequenceId
   * @param signature the result of eth.sign on the operationHash sha3(toAddress, value, data, expireTime, sequenceId)
   */
  function sendMultiSig(address toAddress, uint value, bytes data, uint expireTime, uint sequenceId, bytes signature) onlysigner {
    // Verify the other signer
    var operationHash = sha3("ETHER", toAddress, value, data, expireTime, sequenceId);
    
    var otherSigner = verifyMultiSig(toAddress, operationHash, signature, expireTime, sequenceId);

    // Success, send the transaction
    if (!(toAddress.call.value(value)(data))) {
      // Failed executing transaction
      throw;
    }
    Transacted(msg.sender, otherSigner, operationHash, toAddress, value, data);
  }
  
  /**
   * Execute a multi-signature token transfer from this wallet using 2 signers: one from msg.sender and the other from ecrecover.
   * The signature is a signed form (using eth.sign) of tightly packed toAddress, value, tokenContractAddress, expireTime and sequenceId
   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.
   *
   * @param toAddress the destination address to send an outgoing transaction
   * @param value the amount in tokens to be sent
   * @param tokenContractAddress the address of the erc20 token contract
   * @param expireTime the number of seconds since 1970 for which this transaction is valid
   * @param sequenceId the unique sequence id obtainable from getNextSequenceId
   * @param signature the result of eth.sign on the operationHash sha3(toAddress, value, tokenContractAddress, expireTime, sequenceId)
   */
  function sendMultiSigToken(address toAddress, uint value, address tokenContractAddress, uint expireTime, uint sequenceId, bytes signature) onlysigner {
    // Verify the other signer
    var operationHash = sha3("ERC20", toAddress, value, tokenContractAddress, expireTime, sequenceId);
    
    var otherSigner = verifyMultiSig(toAddress, operationHash, signature, expireTime, sequenceId);
    
    ERC20Interface instance = ERC20Interface(tokenContractAddress);
    if (!instance.transfer(toAddress, value)) {
        throw;
    }
    TokenTransacted(msg.sender, otherSigner, operationHash, toAddress, value, tokenContractAddress);
  }

  /**
   * Execute a token flush from one of the forwarder addresses. This transfer needs only a single signature and can be done by any signer
   *
   * @param forwarderAddress the address of the forwarder address to flush the tokens from
   * @param tokenContractAddress the address of the erc20 token contract
   */
  function flushForwarderTokens(address forwarderAddress, address tokenContractAddress) onlysigner {    
    Forwarder forwarder = Forwarder(forwarderAddress);
    forwarder.flushTokens(tokenContractAddress);
  }  
  
  /**
   * Do common multisig verification for both eth sends and erc20token transfers
   *
   * @param toAddress the destination address to send an outgoing transaction
   * @param operationHash the sha3 of the toAddress, value, data/tokenContractAddress and expireTime
   * @param signature the tightly packed signature of r, s, and v as an array of 65 bytes (returned by eth.sign)
   * @param expireTime the number of seconds since 1970 for which this transaction is valid
   * @param sequenceId the unique sequence id obtainable from getNextSequenceId
   * returns address of the address to send tokens or eth to
   */
  function verifyMultiSig(address toAddress, bytes32 operationHash, bytes signature, uint expireTime, uint sequenceId) private returns (address) {

    var otherSigner = recoverAddressFromSignature(operationHash, signature);

    // Verify if we are in safe mode. In safe mode, the wallet can only send to signers
    if (safeMode && !isSigner(toAddress)) {
      // We are in safe mode and the toAddress is not a signer. Disallow!
      throw;
    }
    // Verify that the transaction has not expired
    if (expireTime < block.timestamp) {
      // Transaction expired
      throw;
    }

    // Try to insert the sequence ID. Will throw if the sequence id was invalid
    tryInsertSequenceId(sequenceId);

    if (!isSigner(otherSigner)) {
      // Other signer not on this wallet or operation does not match arguments
      throw;
    }
    if (otherSigner == msg.sender) {
      // Cannot approve own transaction
      throw;
    }

    return otherSigner;
  }

  /**
   * Irrevocably puts contract into safe mode. When in this mode, transactions may only be sent to signing addresses.
   */
  function activateSafeMode() onlysigner {
    safeMode = true;
    SafeModeActivated(msg.sender);
  }

  /**
   * Determine if an address is a signer on this wallet
   * @param signer address to check
   * returns boolean indicating whether address is signer or not
   */
  function isSigner(address signer) returns (bool) {
    // Iterate through all signers on the wallet and
    for (uint i = 0; i < signers.length; i++) {
      if (signers[i] == signer) {
        return true;
      }
    }
    return false;
  }

  /**
   * Gets the second signer's address using ecrecover
   * @param operationHash the sha3 of the toAddress, value, data/tokenContractAddress and expireTime
   * @param signature the tightly packed signature of r, s, and v as an array of 65 bytes (returned by eth.sign)
   * returns address recovered from the signature
   */
  function recoverAddressFromSignature(bytes32 operationHash, bytes signature) private returns (address) {
    if (signature.length != 65) {
      throw;
    }
    // We need to unpack the signature, which is given as an array of 65 bytes (from eth.sign)
    bytes32 r;
    bytes32 s;
    uint8 v;
    assembly {
      r := mload(add(signature, 32))
      s := mload(add(signature, 64))
      v := and(mload(add(signature, 65)), 255)
    }
    if (v < 27) {
      v += 27; // Ethereum versions are 27 or 28 as opposed to 0 or 1 which is submitted by some signing libs
    }
    return ecrecover(operationHash, v, r, s);
  }

  /**
   * Verify that the sequence id has not been used before and inserts it. Throws if the sequence ID was not accepted.
   * We collect a window of up to 10 recent sequence ids, and allow any sequence id that is not in the window and
   * greater than the minimum element in the window.
   * @param sequenceId to insert into array of stored ids
   */
  function tryInsertSequenceId(uint sequenceId) onlysigner private {
    // Keep a pointer to the lowest value element in the window
    uint lowestValueIndex = 0;
    for (uint i = 0; i < SEQUENCE_ID_WINDOW_SIZE; i++) {
      if (recentSequenceIds[i] == sequenceId) {
        // This sequence ID has been used before. Disallow!
        throw;
      }
      if (recentSequenceIds[i] < recentSequenceIds[lowestValueIndex]) {
        lowestValueIndex = i;
      }
    }
    if (sequenceId < recentSequenceIds[lowestValueIndex]) {
      // The sequence ID being used is lower than the lowest value in the window
      // so we cannot accept it as it may have been used before
      throw;
    }
    if (sequenceId > (recentSequenceIds[lowestValueIndex] + 10000)) {
      // Block sequence IDs which are much higher than the lowest value
      // This prevents people blocking the contract by using very large sequence IDs quickly
      throw;
    }
    recentSequenceIds[lowestValueIndex] = sequenceId;
  }

  /**
   * Gets the next available sequence ID for signing when using executeAndConfirm
   * returns the sequenceId one higher than the highest currently stored
   */
  function getNextSequenceId() returns (uint) {
    uint highestSequenceId = 0;
    for (uint i = 0; i < SEQUENCE_ID_WINDOW_SIZE; i++) {
      if (recentSequenceIds[i] > highestSequenceId) {
        highestSequenceId = recentSequenceIds[i];
      }
    }
    return highestSequenceId + 1;
  }
}