creation_sourcecode: // SPDX-License-Identifier: AGPL-3.0-or-later
  pragma solidity 0.8.19;
  pragma abicoder v2;
  
  /**
   * @dev Wrappers over Solidity's arithmetic operations with added overflow
   * checks.
   *
   * Arithmetic operations in Solidity wrap on overflow. This can easily result
   * in bugs, because programmers usually assume that an overflow raises an
   * error, which is the standard behavior in high level programming languages.
   * `SafeMath` restores this intuition by reverting the transaction when an
   * operation overflows.
   *
   * Using this library instead of the unchecked operations eliminates an entire
   * class of bugs, so it's recommended to use it always.
   */
  library SafeMath {
      /**
       * @dev Returns the addition of two unsigned integers, with an overflow flag.
       */
      function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          uint256 c = a + b;
          if (c < a) return (false, 0);
          return (true, c);
      }
  
      /**
       * @dev Returns the substraction of two unsigned integers, with an overflow flag.
       */
      function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          if (b > a) return (false, 0);
          return (true, a - b);
      }
  
      /**
       * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
       */
      function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
          // benefit is lost if 'b' is also tested.
          // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
          if (a == 0) return (true, 0);
          uint256 c = a * b;
          if (c / a != b) return (false, 0);
          return (true, c);
      }
  
      /**
       * @dev Returns the division of two unsigned integers, with a division by zero flag.
       */
      function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          if (b == 0) return (false, 0);
          return (true, a / b);
      }
  
      /**
       * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
       */
      function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          if (b == 0) return (false, 0);
          return (true, a % b);
      }
  
      /**
       * @dev Returns the addition of two unsigned integers, reverting on
       * overflow.
       *
       * Counterpart to Solidity's `+` operator.
       *
       * Requirements:
       *
       * - Addition cannot overflow.
       */
      function add(uint256 a, uint256 b) internal pure returns (uint256) {
          uint256 c = a + b;
          require(c >= a, "SafeMath: addition overflow");
          return c;
      }
  
      /**
       * @dev Returns the subtraction of two unsigned integers, reverting on
       * overflow (when the result is negative).
       *
       * Counterpart to Solidity's `-` operator.
       *
       * Requirements:
       *
       * - Subtraction cannot overflow.
       */
      function sub(uint256 a, uint256 b) internal pure returns (uint256) {
          require(b <= a, "SafeMath: subtraction overflow");
          return a - b;
      }
  
      /**
       * @dev Returns the multiplication of two unsigned integers, reverting on
       * overflow.
       *
       * Counterpart to Solidity's `*` operator.
       *
       * Requirements:
       *
       * - Multiplication cannot overflow.
       */
      function mul(uint256 a, uint256 b) internal pure returns (uint256) {
          if (a == 0) return 0;
          uint256 c = a * b;
          require(c / a == b, "SafeMath: multiplication overflow");
          return c;
      }
  
      /**
       * @dev Returns the integer division of two unsigned integers, reverting on
       * division by zero. The result is rounded towards zero.
       *
       * Counterpart to Solidity's `/` operator. Note: this function uses a
       * `revert` opcode (which leaves remaining gas untouched) while Solidity
       * uses an invalid opcode to revert (consuming all remaining gas).
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function div(uint256 a, uint256 b) internal pure returns (uint256) {
          require(b > 0, "SafeMath: division by zero");
          return a / b;
      }
  
      /**
       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
       * reverting when dividing by zero.
       *
       * Counterpart to Solidity's `%` operator. This function uses a `revert`
       * opcode (which leaves remaining gas untouched) while Solidity uses an
       * invalid opcode to revert (consuming all remaining gas).
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function mod(uint256 a, uint256 b) internal pure returns (uint256) {
          require(b > 0, "SafeMath: modulo by zero");
          return a % b;
      }
  
      /**
       * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
       * overflow (when the result is negative).
       *
       * CAUTION: This function is deprecated because it requires allocating memory for the error
       * message unnecessarily. For custom revert reasons use {trySub}.
       *
       * Counterpart to Solidity's `-` operator.
       *
       * Requirements:
       *
       * - Subtraction cannot overflow.
       */
      function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
          require(b <= a, errorMessage);
          return a - b;
      }
  
      /**
       * @dev Returns the integer division of two unsigned integers, reverting with custom message on
       * division by zero. The result is rounded towards zero.
       *
       * CAUTION: This function is deprecated because it requires allocating memory for the error
       * message unnecessarily. For custom revert reasons use {tryDiv}.
       *
       * Counterpart to Solidity's `/` operator. Note: this function uses a
       * `revert` opcode (which leaves remaining gas untouched) while Solidity
       * uses an invalid opcode to revert (consuming all remaining gas).
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
          require(b > 0, errorMessage);
          return a / b;
      }
  
      /**
       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
       * reverting with custom message when dividing by zero.
       *
       * CAUTION: This function is deprecated because it requires allocating memory for the error
       * message unnecessarily. For custom revert reasons use {tryMod}.
       *
       * Counterpart to Solidity's `%` operator. This function uses a `revert`
       * opcode (which leaves remaining gas untouched) while Solidity uses an
       * invalid opcode to revert (consuming all remaining gas).
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
          require(b > 0, errorMessage);
          return a % b;
      }
  }
  
  /**
   * @dev Interface of the ERC20 standard as defined in the EIP.
   */
  interface IERC20 {
      /**
       * @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 `recipient`.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * Emits a {Transfer} event.
       */
      function transfer(address recipient, 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 `sender` to `recipient` 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 sender, address recipient, uint256 amount) external returns (bool);
  
      /**
       * @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 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 GSN 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 payable) {
  		// Since Solidity 0.8, msg.sender is not payable anymore. You need to cast it to payable first.	
          // Old code was       return msg.sender;
  		
  		return payable(msg.sender);		
      }
  
      function _msgData() internal view virtual returns (bytes memory) {
          this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
          return msg.data;
      }
  }
  
  /**
   * @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
       * ====
       */
      function isContract(address account) internal view returns (bool) {
          // This method relies on extcodesize, which returns 0 for contracts in
          // construction, since the code is only stored at the end of the
          // constructor execution.
  
          uint256 size;
          // solhint-disable-next-line no-inline-assembly
          assembly { size := extcodesize(account) }
          return size > 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://diligence.consensys.net/posts/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/v0.5.11/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");
  
          // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
          (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 functionCall(target, data, "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");
          require(isContract(target), "Address: call to non-contract");
  
          // solhint-disable-next-line avoid-low-level-calls
          (bool success, bytes memory returndata) = target.call{ value: value }(data);
          return _verifyCallResult(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) {
          require(isContract(target), "Address: static call to non-contract");
  
          // solhint-disable-next-line avoid-low-level-calls
          (bool success, bytes memory returndata) = target.staticcall(data);
          return _verifyCallResult(success, returndata, errorMessage);
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but performing a delegate call.
       *
       * _Available since v3.3._
       */
      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 v3.3._
       */
      function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
          require(isContract(target), "Address: delegate call to non-contract");
  
          // solhint-disable-next-line avoid-low-level-calls
          (bool success, bytes memory returndata) = target.delegatecall(data);
          return _verifyCallResult(success, returndata, errorMessage);
      }
  
      function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
          if (success) {
              return returndata;
          } else {
              // 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
  
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      let returndata_size := mload(returndata)
                      revert(add(32, returndata), returndata_size)
                  }
              } else {
                  revert(errorMessage);
              }
          }
      }
  }
  
  /**
   * @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 SafeMath for uint256;
      using Address for address;
  
      function safeTransfer(IERC20 token, address to, uint256 value) internal {
          _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
      }
  
      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'
          // solhint-disable-next-line max-line-length
          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));
      }
  
      function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
          uint256 newAllowance = token.allowance(address(this), spender).add(value);
          _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
      }
  
      function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
          uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
          _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
      }
  
      /**
       * @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");
          if (returndata.length > 0) { // Return data is optional
              // solhint-disable-next-line max-line-length
              require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
          }
      }
  }
  
  contract TokenSwapper {
  
          error SwapNumberAlreadyUsed();
          error ExpiryDateNotWithinFutureYear();
          error AddressValueZeroOrInvalid();
          error TokensAddressesCannotBeSame();
          error TokenAmountCannotBeZero(); 
          error SwapNumberDoesNotExistOrExpired();
          error SwapNoMoreOpen();
          error InCorrectSwapExecute(); 
          error SwapNotYetExpired();
  
  
      enum States {
          INVALID,
          OPEN,
          CLOSED,
          EXPIRED
      }
  
      struct Swap {
          address executor;
          address openingToken;
          uint256 tokensToOpen;
          address closingToken;
          uint256 tokensToClose;
          uint256 expiry;
          States status;
      }
  
      //swaps stored as allSwaps[swapOriginator][swapNumber]
      mapping(address => mapping(uint256 => Swap)) allSwaps;
  
      event Opened(address indexed originator, address executor, address indexed openingToken, uint256 tokensToOpen, address closingToken, uint256 tokensToClose);
      event Closed(address indexed originator, address executor, address indexed openingToken, uint256 tokensToOpen, address closingToken, uint256 tokensToClose);
      event Expired(address indexed originator, address executor, address indexed openingToken, uint256 tokensToOpen, address closingToken, uint256 swapNumber);
  
      function open(uint256 swapNumber, address _executor, address _openingToken, uint256 _tokensToOpen, address _closingToken, uint256 _tokensToClose, uint256 _expiry) external returns(bool) {
          //sanity checks
  
          // check if swap number already used. use expiry from struct as reference
          if( allSwaps[msg.sender][swapNumber].expiry > 0 ) {
              revert SwapNumberAlreadyUsed();      
          }
  
          if( _expiry <= block.timestamp || _expiry > block.timestamp + 365 days ) {
              revert ExpiryDateNotWithinFutureYear();
          }
  
          if( _executor == address(0) ) {
              revert AddressValueZeroOrInvalid();
          } 
  
          if( _openingToken == address(0) ) {
              revert AddressValueZeroOrInvalid();
          } 
  
          if( _closingToken == address(0) ) {
              revert AddressValueZeroOrInvalid();
          } 
  
          if ( _openingToken == _closingToken ) {
              revert TokensAddressesCannotBeSame();
          }
  
          if( _tokensToOpen == 0 ) {
              revert TokenAmountCannotBeZero(); 
          }
          
          if( _tokensToClose == 0 ) {
              revert TokenAmountCannotBeZero(); 
          }
  
  
          //fetch details of swap
          Swap memory swap = allSwaps[msg.sender][swapNumber];
  
          //fill in new swap details
          swap = Swap({
              executor: _executor,
              openingToken: _openingToken,
              tokensToOpen: _tokensToOpen,
              closingToken: _closingToken,
              tokensToClose: _tokensToClose,
              expiry: _expiry,
              status: States.OPEN
          });
  
          //store swap details in storage
          allSwaps[msg.sender][swapNumber] = swap;
  
          //transfer tokensToOpen from swap creator
          IERC20 token = IERC20(_openingToken);
          SafeERC20.safeTransferFrom(token, msg.sender, address(this), _tokensToOpen);
  
          //emit event
          emit Opened(msg.sender, _executor, _openingToken, _tokensToOpen, _closingToken, _tokensToClose);
  
          return true;
      }
  
      function close(address originator, uint256 swapNumber) external returns(bool) {
          //check if swap number does not exists then revert
          if( !(allSwaps[originator][swapNumber].expiry > 0) ) {
              revert SwapNumberDoesNotExistOrExpired();        
          }
  
          //fetch swap data
          Swap storage swap = allSwaps[originator][swapNumber];
  
          if( swap.status != States.OPEN ) {
              revert SwapNoMoreOpen();
          }
  
          if( msg.sender != swap.executor ) { 
              revert InCorrectSwapExecute(); 
          }
  
          if( block.timestamp > swap.expiry ) { 
              revert SwapNumberDoesNotExistOrExpired();
          }
  
          //set swap to closed
          swap.status = States.CLOSED;
  
          //transfer tokensToClose from msg.sender to originator
          IERC20 tokenB = IERC20(swap.closingToken);
          SafeERC20.safeTransferFrom(tokenB, msg.sender, originator, swap.tokensToClose);
  
          //transfer tokensToOpen from originator to msg.sender
          IERC20 tokenA = IERC20(swap.openingToken);
          SafeERC20.safeTransfer(tokenA, msg.sender, swap.tokensToOpen);
  
          //emit event
          emit Closed(originator, swap.executor , swap.openingToken, swap.tokensToOpen, swap.closingToken, swap.tokensToClose);
  
          return true;
      }
  
      function expire(address originator, uint256 swapNumber) external returns(bool) {
  
          // check if swap number does not exists then revert
          if( !(allSwaps[originator][swapNumber].expiry > 0) ) {
              revert SwapNumberDoesNotExistOrExpired();
          }
  
          // use storage instead of memory to save changes directly inside 
          Swap storage swap = allSwaps[originator][swapNumber];
  
          if( swap.status != States.OPEN ) {
              revert SwapNoMoreOpen();
          } 
  
          if (block.timestamp <= swap.expiry) {
              revert SwapNotYetExpired();
          } 
  
          //set swap to expired
          swap.status = States.EXPIRED;
  
          //transfer tokensToOpen back to originator
          IERC20 token = IERC20(swap.openingToken);
          SafeERC20.safeTransfer(token, originator, swap.tokensToOpen);
  
          //emit event
          emit Expired(originator, swap.executor , swap.openingToken, swap.tokensToOpen, swap.closingToken, swap.tokensToClose);
  
          return true;
      }
  
      function getSwapData(address originator, uint256 swapNumber) external view
      returns(Swap memory, uint256 swapState){
          Swap memory swap = allSwaps[originator][swapNumber];
          return(swap, uint256(swap.status));
      }
  
  
  }