struct Data {
    IERC20 sellToken;
    IERC20 buyToken;
    address receiver;
    uint256 sellAmount;
    uint256 buyAmount;
    uint32 validTo;
    bytes32 appData;
    uint256 feeAmount;
    bytes32 kind;
    bool partiallyFillable;
    bytes32 sellTokenBalance;
    bytes32 buyTokenBalance;
}

bytes32 constant KIND_SELL = keccak256("sell");
bytes32 constant KIND_BUY = keccak256("buy");
bytes32 constant BALANCE_ERC20 = keccak256("erc20");
bytes32 constant BALANCE_EXTERNAL = keccak256("external");
bytes32 constant BALANCE_INTERNAL = keccak256("internal");
uint256 constant UID_LENGTH = 56;

function hash(
    Data memory order,
    bytes32 domainSeparator
) internal pure returns (bytes32);

function actualReceiver(
    Data memory order,
    address owner
) internal pure returns (address);

function packOrderUidParams(
    bytes memory orderUid,
    bytes32 orderDigest,
    address owner,
    uint32 validTo
) internal pure;

function extractOrderUidParams(
    bytes calldata orderUid
) internal pure returns (
    bytes32 orderDigest,
    address owner,
    uint32 validTo
);