// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

library StringToBytes32 {
    error InvalidStringLength();

    function toBytes32(string memory str) internal pure returns (bytes32) {
        // Converting a string to bytes32 for immutable storage
        bytes memory stringBytes = bytes(str);

        // We can store up to 31 bytes of data as 1 byte is for encoding length
        if (stringBytes.length == 0 || stringBytes.length > 31) revert InvalidStringLength();

        uint256 stringNumber = uint256(bytes32(stringBytes));

        // Storing string length as the last byte of the data
        stringNumber |= 0xff & stringBytes.length;
        return bytes32(stringNumber);
    }
}

library Bytes32ToString {
    function toTrimmedString(bytes32 stringData) internal pure returns (string memory converted) {
        // recovering string length as the last byte of the data
        uint256 length = 0xff & uint256(stringData);

        // restoring the string with the correct length
        assembly {
            converted := mload(0x40)
            // new "memory end" including padding (the string isn't larger than 32 bytes)
            mstore(0x40, add(converted, 0x40))
            // store length in memory
            mstore(converted, length)
            // write actual data
            mstore(add(converted, 0x20), stringData)
        }
    }
}