pragma solidity ^0.5.2;
contract Admin {
    address internal _admin;
    event AdminChanged(address oldAdmin, address newAdmin);
    /// @notice gives the current administrator of this contract.
    /// @return the current administrator of this contract.
    function getAdmin() external view returns (address) {
        return _admin;
    }
    /// @notice change the administrator to be `newAdmin`.
    /// @param newAdmin address of the new administrator.
    function changeAdmin(address newAdmin) external {
        require(msg.sender == _admin, "only admin can change admin");
        emit AdminChanged(_admin, newAdmin);
        _admin = newAdmin;
    }
}
pragma solidity ^0.5.2;
import "./Admin.sol";
contract SuperOperators is Admin {
    mapping(address => bool) internal _superOperators;
    event SuperOperator(address superOperator, bool enabled);
    /// @notice Enable or disable the ability of `superOperator` to transfer tokens of all (superOperator rights).
    /// @param superOperator address that will be given/removed superOperator right.
    /// @param enabled set whether the superOperator is enabled or disabled.
    function setSuperOperator(address superOperator, bool enabled) external {
        require(
            msg.sender == _admin,
            "only admin is allowed to add super operators"
        );
        _superOperators[superOperator] = enabled;
        emit SuperOperator(superOperator, enabled);
    }
    /// @notice check whether address `who` is given superOperator rights.
    /// @param who The address to query.
    /// @return whether the address has superOperator rights.
    function isSuperOperator(address who) public view returns (bool) {
        return _superOperators[who];
    }
}
pragma solidity ^0.5.2;
/* interface */
contract ERC20Events {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}
pragma solidity ^0.5.2;
library BytesUtil {
    function memcpy(uint256 dest, uint256 src, uint256 len) internal pure {
        // Copy word-length chunks while possible
        for (; len >= 32; len -= 32) {
            assembly {
                mstore(dest, mload(src))
            }
            dest += 32;
            src += 32;
        }
        // Copy remaining bytes
        uint256 mask = 256**(32 - len) - 1;
        assembly {
            let srcpart := and(mload(src), not(mask))
            let destpart := and(mload(dest), mask)
            mstore(dest, or(destpart, srcpart))
        }
    }
    function pointerToBytes(uint256 src, uint256 len)
        internal
        pure
        returns (bytes memory)
    {
        bytes memory ret = new bytes(len);
        uint256 retptr;
        assembly {
            retptr := add(ret, 32)
        }
        memcpy(retptr, src, len);
        return ret;
    }
    function addressToBytes(address a) internal pure returns (bytes memory b) {
        assembly {
            let m := mload(0x40)
            mstore(
                add(m, 20),
                xor(0x140000000000000000000000000000000000000000, a)
            )
            mstore(0x40, add(m, 52))
            b := m
        }
    }
    function uint256ToBytes(uint256 a) internal pure returns (bytes memory b) {
        assembly {
            let m := mload(0x40)
            mstore(add(m, 32), a)
            mstore(0x40, add(m, 64))
            b := m
        }
    }
    function doFirstParamEqualsAddress(bytes memory data, address _address)
        internal
        pure
        returns (bool)
    {
        if (data.length < (36 + 32)) {
            return false;
        }
        uint256 value;
        assembly {
            value := mload(add(data, 36))
        }
        return value == uint256(_address);
    }
    function doParamEqualsUInt256(bytes memory data, uint256 i, uint256 value)
        internal
        pure
        returns (bool)
    {
        if (data.length < (36 + (i + 1) * 32)) {
            return false;
        }
        uint256 offset = 36 + i * 32;
        uint256 valuePresent;
        assembly {
            valuePresent := mload(add(data, offset))
        }
        return valuePresent == value;
    }
    function overrideFirst32BytesWithAddress(
        bytes memory data,
        address _address
    ) internal pure returns (bytes memory) {
        uint256 dest;
        assembly {
            dest := add(data, 48)
        } // 48 = 32 (offset) + 4 (func sig) + 12 (address is only 20 bytes)
        bytes memory addressBytes = addressToBytes(_address);
        uint256 src;
        assembly {
            src := add(addressBytes, 32)
        }
        memcpy(dest, src, 20);
        return data;
    }
    function overrideFirstTwo32BytesWithAddressAndInt(
        bytes memory data,
        address _address,
        uint256 _value
    ) internal pure returns (bytes memory) {
        uint256 dest;
        uint256 src;
        assembly {
            dest := add(data, 48)
        } // 48 = 32 (offset) + 4 (func sig) + 12 (address is only 20 bytes)
        bytes memory bbytes = addressToBytes(_address);
        assembly {
            src := add(bbytes, 32)
        }
        memcpy(dest, src, 20);
        assembly {
            dest := add(data, 68)
        } // 48 = 32 (offset) + 4 (func sig) + 32 (next slot)
        bbytes = uint256ToBytes(_value);
        assembly {
            src := add(bbytes, 32)
        }
        memcpy(dest, src, 32);
        return data;
    }
}
pragma solidity 0.5.9;
import "./Sand/erc20/ERC20ExecuteExtension.sol";
import "./Sand/erc20/ERC20BaseToken.sol";
import "./Sand/erc20/ERC20BasicApproveExtension.sol";
contract Sand is ERC20ExecuteExtension, ERC20BasicApproveExtension, ERC20BaseToken {
    constructor(address sandAdmin, address executionAdmin, address beneficiary) public {
        _admin = sandAdmin;
        _executionAdmin = executionAdmin;
        _mint(beneficiary, 3000000000000000000000000000);
    }
    /// @notice A descriptive name for the tokens
    /// @return name of the tokens
    function name() public view returns (string memory) {
        return "SAND";
    }
    /// @notice An abbreviated name for the tokens
    /// @return symbol of the tokens
    function symbol() public view returns (string memory) {
        return "SAND";
    }
}
pragma solidity 0.5.9;
import "../../../contracts_common/src/Interfaces/ERC20Events.sol";
import "../../../contracts_common/src/BaseWithStorage/SuperOperators.sol";
contract ERC20BaseToken is SuperOperators, ERC20Events {
    uint256 internal _totalSupply;
    mapping(address => uint256) internal _balances;
    mapping(address => mapping(address => uint256)) internal _allowances;
    /// @notice Gets the total number of tokens in existence.
    /// @return the total number of tokens in existence.
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }
    /// @notice Gets the balance of `owner`.
    /// @param owner The address to query the balance of.
    /// @return The amount owned by `owner`.
    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }
    /// @notice gets allowance of `spender` for `owner`'s tokens.
    /// @param owner address whose token is allowed.
    /// @param spender address allowed to transfer.
    /// @return the amount of token `spender` is allowed to transfer on behalf of `owner`.
    function allowance(address owner, address spender)
        public
        view
        returns (uint256 remaining)
    {
        return _allowances[owner][spender];
    }
    /// @notice returns the number of decimals for that token.
    /// @return the number of decimals.
    function decimals() public view returns (uint8) {
        return uint8(18);
    }
    /// @notice Transfer `amount` tokens to `to`.
    /// @param to the recipient address of the tokens transfered.
    /// @param amount the number of tokens transfered.
    /// @return true if success.
    function transfer(address to, uint256 amount)
        public
        returns (bool success)
    {
        _transfer(msg.sender, to, amount);
        return true;
    }
    /// @notice Transfer `amount` tokens from `from` to `to`.
    /// @param from whose token it is transferring from.
    /// @param to the recipient address of the tokens transfered.
    /// @param amount the number of tokens transfered.
    /// @return true if success.
    function transferFrom(address from, address to, uint256 amount)
        public
        returns (bool success)
    {
        if (msg.sender != from && !_superOperators[msg.sender]) {
            uint256 currentAllowance = _allowances[from][msg.sender];
            if (currentAllowance != (2**256) - 1) {
                // save gas when allowance is maximal by not reducing it (see https://github.com/ethereum/EIPs/issues/717)
                require(currentAllowance >= amount, "Not enough funds allowed");
                _allowances[from][msg.sender] = currentAllowance - amount;
            }
        }
        _transfer(from, to, amount);
        return true;
    }
    /// @notice burn `amount` tokens.
    /// @param amount the number of tokens to burn.
    /// @return true if success.
    function burn(uint256 amount) external returns (bool) {
        _burn(msg.sender, amount);
        return true;
    }
    /// @notice burn `amount` tokens from `owner`.
    /// @param owner address whose token is to burn.
    /// @param amount the number of token to burn.
    /// @return true if success.
    function burnFor(address owner, uint256 amount) external returns (bool) {
        _burn(owner, amount);
        return true;
    }
    /// @notice approve `spender` to transfer `amount` tokens.
    /// @param spender address to be given rights to transfer.
    /// @param amount the number of tokens allowed.
    /// @return true if success.
    function approve(address spender, uint256 amount)
        public
        returns (bool success)
    {
        _approveFor(msg.sender, spender, amount);
        return true;
    }
    /// @notice approve `spender` to transfer `amount` tokens from `owner`.
    /// @param owner address whose token is allowed.
    /// @param spender  address to be given rights to transfer.
    /// @param amount the number of tokens allowed.
    /// @return true if success.
    function approveFor(address owner, address spender, uint256 amount)
        public
        returns (bool success)
    {
        require(
            msg.sender == owner || _superOperators[msg.sender],
            "msg.sender != owner && !superOperator"
        );
        _approveFor(owner, spender, amount);
        return true;
    }
    function addAllowanceIfNeeded(address owner, address spender, uint256 amountNeeded)
        public
        returns (bool success)
    {
        require(
            msg.sender == owner || _superOperators[msg.sender],
            "msg.sender != owner && !superOperator"
        );
        _addAllowanceIfNeeded(owner, spender, amountNeeded);
        return true;
    }
    function _addAllowanceIfNeeded(address owner, address spender, uint256 amountNeeded)
        internal
    {
        if(amountNeeded > 0 && !isSuperOperator(spender)) {
            uint256 currentAllowance = _allowances[owner][spender];
            if(currentAllowance < amountNeeded) {
                _approveFor(owner, spender, amountNeeded);
            }
        }
    }
    function _approveFor(address owner, address spender, uint256 amount)
        internal
    {
        require(
            owner != address(0) && spender != address(0),
            "Cannot approve with 0x0"
        );
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
    function _transfer(address from, address to, uint256 amount) internal {
        require(to != address(0), "Cannot send to 0x0");
        uint256 currentBalance = _balances[from];
        require(currentBalance >= amount, "not enough fund");
        _balances[from] = currentBalance - amount;
        _balances[to] += amount;
        emit Transfer(from, to, amount);
    }
    function _mint(address to, uint256 amount) internal {
        require(to != address(0), "Cannot mint to 0x0");
        require(amount > 0, "cannot mint 0 tokens");
        uint256 currentTotalSupply = _totalSupply;
        uint256 newTotalSupply = currentTotalSupply + amount;
        require(newTotalSupply > currentTotalSupply, "overflow");
        _totalSupply = newTotalSupply;
        _balances[to] += amount;
        emit Transfer(address(0), to, amount);
    }
    function _burn(address from, uint256 amount) internal {
        require(amount > 0, "cannot burn 0 tokens");
        if (msg.sender != from && !_superOperators[msg.sender]) {
            uint256 currentAllowance = _allowances[from][msg.sender];
            require(
                currentAllowance >= amount,
                "Not enough funds allowed"
            );
            if (currentAllowance != (2**256) - 1) {
                // save gas when allowance is maximal by not reducing it (see https://github.com/ethereum/EIPs/issues/717)
                _allowances[from][msg.sender] = currentAllowance - amount;
            }
        }
        uint256 currentBalance = _balances[from];
        require(currentBalance >= amount, "Not enough funds");
        _balances[from] = currentBalance - amount;
        _totalSupply -= amount;
        emit Transfer(from, address(0), amount);
    }
}
pragma solidity 0.5.9;
import "../../../contracts_common/src/Libraries/BytesUtil.sol";
contract ERC20BasicApproveExtension {
    /// @notice approve `target` to spend `amount` and call it with data.
    /// @param target address to be given rights to transfer and destination of the call.
    /// @param amount the number of tokens allowed.
    /// @param data bytes for the call.
    /// @return data of the call.
    function approveAndCall(
        address target,
        uint256 amount,
        bytes calldata data
    ) external payable returns (bytes memory) {
        require(
            BytesUtil.doFirstParamEqualsAddress(data, msg.sender),
            "first param != sender"
        );
        _approveFor(msg.sender, target, amount);
        // solium-disable-next-line security/no-call-value
        (bool success, bytes memory returnData) = target.call.value(msg.value)(data);
        require(success, string(returnData));
        return returnData;
    }
    /// @notice temporarly approve `target` to spend `amount` and call it with data. Previous approvals remains unchanged.
    /// @param target destination of the call, allowed to spend the amount specified
    /// @param amount the number of tokens allowed to spend.
    /// @param data bytes for the call.
    /// @return data of the call.
    function paidCall(
        address target,
        uint256 amount,
        bytes calldata data
    ) external payable returns (bytes memory) {
        require(
            BytesUtil.doFirstParamEqualsAddress(data, msg.sender),
            "first param != sender"
        );
        if (amount > 0) {
            _addAllowanceIfNeeded(msg.sender, target, amount);
        }
        // solium-disable-next-line security/no-call-value
        (bool success, bytes memory returnData) = target.call.value(msg.value)(data);
        require(success, string(returnData));
        return returnData;
    }
    function _approveFor(address owner, address target, uint256 amount) internal;
    function _addAllowanceIfNeeded(address owner, address spender, uint256 amountNeeded) internal;
}
pragma solidity 0.5.9;
contract ERC20ExecuteExtension {
    /// @dev _executionAdmin != _admin so that this super power can be disabled independently
    address internal _executionAdmin;
    event ExecutionAdminAdminChanged(address oldAdmin, address newAdmin);
    /// @notice give the address responsible for adding execution rights.
    /// @return address of the execution administrator.
    function getExecutionAdmin() external view returns (address) {
        return _executionAdmin;
    }
    /// @notice change the execution adminstrator to be `newAdmin`.
    /// @param newAdmin address of the new administrator.
    function changeExecutionAdmin(address newAdmin) external {
        require(msg.sender == _executionAdmin, "only executionAdmin can change executionAdmin");
        emit ExecutionAdminAdminChanged(_executionAdmin, newAdmin);
        _executionAdmin = newAdmin;
    }
    mapping(address => bool) internal _executionOperators;
    event ExecutionOperator(address executionOperator, bool enabled);
    /// @notice set `executionOperator` as executionOperator: `enabled`.
    /// @param executionOperator address that will be given/removed executionOperator right.
    /// @param enabled set whether the executionOperator is enabled or disabled.
    function setExecutionOperator(address executionOperator, bool enabled) external {
        require(
            msg.sender == _executionAdmin,
            "only execution admin is allowed to add execution operators"
        );
        _executionOperators[executionOperator] = enabled;
        emit ExecutionOperator(executionOperator, enabled);
    }
    /// @notice check whether address `who` is given executionOperator rights.
    /// @param who The address to query.
    /// @return whether the address has executionOperator rights.
    function isExecutionOperator(address who) public view returns (bool) {
        return _executionOperators[who];
    }
    /// @notice execute on behalf of the contract.
    /// @param to destination address fo the call.
    /// @param gasLimit exact amount of gas to be passed to the call.
    /// @param data the bytes sent to the destination address.
    /// @return success whether the execution was successful.
    /// @return returnData data resulting from the execution.
    function executeWithSpecificGas(address to, uint256 gasLimit, bytes calldata data) external returns (bool success, bytes memory returnData) {
        require(_executionOperators[msg.sender], "only execution operators allowed to execute on SAND behalf");
        (success, returnData) = to.call.gas(gasLimit)(data);
        assert(gasleft() > gasLimit / 63); // not enough gas provided, assert to throw all gas // TODO use EIP-1930
    }
    /// @notice approve a specific amount of token for `from` and execute on behalf of the contract.
    /// @param from address of which token will be transfered.
    /// @param to destination address fo the call.
    /// @param amount number of tokens allowed that can be transfer by the code at `to`.
    /// @param gasLimit exact amount of gas to be passed to the call.
    /// @param data the bytes sent to the destination address.
    /// @return success whether the execution was successful.
    /// @return returnData data resulting from the execution.
    function approveAndExecuteWithSpecificGas(
        address from,
        address to,
        uint256 amount,
        uint256 gasLimit,
        bytes calldata data
    ) external returns (bool success, bytes memory returnData) {
        require(_executionOperators[msg.sender], "only execution operators allowed to execute on SAND behalf");
        return _approveAndExecuteWithSpecificGas(from, to, amount, gasLimit, data);
    }
    /// @dev the reason for this function is that charging for gas here is more gas-efficient than doing it in the caller.
    /// @notice approve a specific amount of token for `from` and execute on behalf of the contract. Plus charge the gas required to perform it.
    /// @param from address of which token will be transfered.
    /// @param to destination address fo the call.
    /// @param amount number of tokens allowed that can be transfer by the code at `to`.
    /// @param gasLimit exact amount of gas to be passed to the call.
    /// @param tokenGasPrice price in token for the gas to be charged.
    /// @param baseGasCharge amount of gas charged on top of the gas used for the call.
    /// @param tokenReceiver recipient address of the token charged for the gas used.
    /// @param data the bytes sent to the destination address.
    /// @return success whether the execution was successful.
    /// @return returnData data resulting from the execution.
    function approveAndExecuteWithSpecificGasAndChargeForIt(
        address from,
        address to,
        uint256 amount,
        uint256 gasLimit,
        uint256 tokenGasPrice,
        uint256 baseGasCharge,
        address tokenReceiver,
        bytes calldata data
    ) external returns (bool success, bytes memory returnData) {
        uint256 initialGas = gasleft();
        require(_executionOperators[msg.sender], "only execution operators allowed to execute on SAND behalf");
        (success, returnData) = _approveAndExecuteWithSpecificGas(from, to, amount, gasLimit, data);
        if (tokenGasPrice > 0) {
            _charge(from, gasLimit, tokenGasPrice, initialGas, baseGasCharge, tokenReceiver);
        }
    }
    /// @notice transfer 1amount1 token from `from` to `to` and charge the gas required to perform that transfer.
    /// @param from address of which token will be transfered.
    /// @param to destination address fo the call.
    /// @param amount number of tokens allowed that can be transfer by the code at `to`.
    /// @param gasLimit exact amount of gas to be passed to the call.
    /// @param tokenGasPrice price in token for the gas to be charged.
    /// @param baseGasCharge amount of gas charged on top of the gas used for the call.
    /// @param tokenReceiver recipient address of the token charged for the gas used.
    /// @return whether the transfer was successful.
    function transferAndChargeForGas(
        address from,
        address to,
        uint256 amount,
        uint256 gasLimit,
        uint256 tokenGasPrice,
        uint256 baseGasCharge,
        address tokenReceiver
    ) external returns (bool) {
        uint256 initialGas = gasleft();
        require(_executionOperators[msg.sender], "only execution operators allowed to perfrom transfer and charge");
        _transfer(from, to, amount);
        if (tokenGasPrice > 0) {
            _charge(from, gasLimit, tokenGasPrice, initialGas, baseGasCharge, tokenReceiver);
        }
        return true;
    }
    function _charge(
        address from,
        uint256 gasLimit,
        uint256 tokenGasPrice,
        uint256 initialGas,
        uint256 baseGasCharge,
        address tokenReceiver
    ) internal {
        uint256 gasCharge = initialGas - gasleft();
        if(gasCharge > gasLimit) {
            gasCharge = gasLimit;
        }
        gasCharge += baseGasCharge;
        uint256 tokensToCharge = gasCharge * tokenGasPrice;
        require(tokensToCharge / gasCharge == tokenGasPrice, "overflow");
        _transfer(from, tokenReceiver, tokensToCharge);
    }
    function _approveAndExecuteWithSpecificGas(
        address from,
        address to,
        uint256 amount,
        uint256 gasLimit,
        bytes memory data
    ) internal returns (bool success, bytes memory returnData) {
        if (amount > 0) {
            _addAllowanceIfNeeded(from, to, amount);
        }
        (success, returnData) = to.call.gas(gasLimit)(data);
        assert(gasleft() > gasLimit / 63); // not enough gas provided, assert to throw all gas // TODO use EIP-1930
    }
    function _transfer(address from, address to, uint256 amount) internal;
    function _addAllowanceIfNeeded(address owner, address spender, uint256 amountNeeded) internal;
}

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;
  }
}