CounterFacts™

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

/// @notice Library to encode strings in Base64.
/// @author Solady (https://github.com/vectorized/solady/blob/main/src/utils/Base64.sol)
/// @author Modified from Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/Base64.sol)
/// @author Modified from (https://github.com/Brechtpd/base64/blob/main/base64.sol) by Brecht Devos - <brecht@loopring.org>.
library Base64 {
    /// @dev Encodes `data` using the base64 encoding described in RFC 4648.
    /// See: https://datatracker.ietf.org/doc/html/rfc4648
    /// @param fileSafe  Whether to replace '+' with '-' and '/' with '_'.
    /// @param noPadding Whether to strip away the padding.
    function encode(bytes memory data, bool fileSafe, bool noPadding)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let dataLength := mload(data)

            if dataLength {
                // Multiply by 4/3 rounded up.
                // The `shl(2, ...)` is equivalent to multiplying by 4.
                let encodedLength := shl(2, div(add(dataLength, 2), 3))

                // Set `result` to point to the start of the free memory.
                result := mload(0x40)

                // Store the table into the scratch space.
                // Offsetted by -1 byte so that the `mload` will load the character.
                // We will rewrite the free memory pointer at `0x40` later with
                // the allocated size.
                // The magic constant 0x0230 will translate "-_" + "+/".
                mstore(0x1f, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdef")
                mstore(0x3f, sub("ghijklmnopqrstuvwxyz0123456789-_", mul(iszero(fileSafe), 0x0230)))

                // Skip the first slot, which stores the length.
                let ptr := add(result, 0x20)
                let end := add(ptr, encodedLength)

                // Run over the input, 3 bytes at a time.
                for {} 1 {} {
                    data := add(data, 3) // Advance 3 bytes.
                    let input := mload(data)

                    // Write 4 bytes. Optimized for fewer stack operations.
                    mstore8(0, mload(and(shr(18, input), 0x3F)))
                    mstore8(1, mload(and(shr(12, input), 0x3F)))
                    mstore8(2, mload(and(shr(6, input), 0x3F)))
                    mstore8(3, mload(and(input, 0x3F)))
                    mstore(ptr, mload(0x00))

                    ptr := add(ptr, 4) // Advance 4 bytes.

                    if iszero(lt(ptr, end)) { break }
                }

                // Allocate the memory for the string.
                // Add 31 and mask with `not(31)` to round the
                // free memory pointer up the next multiple of 32.
                mstore(0x40, and(add(end, 31), not(31)))

                // Equivalent to `o = [0, 2, 1][dataLength % 3]`.
                let o := div(2, mod(dataLength, 3))

                // Offset `ptr` and pad with '='. We can simply write over the end.
                mstore(sub(ptr, o), shl(240, 0x3d3d))
                // Set `o` to zero if there is padding.
                o := mul(iszero(iszero(noPadding)), o)
                // Zeroize the slot after the string.
                mstore(sub(ptr, o), 0)
                // Write the length of the string.
                mstore(result, sub(encodedLength, o))
            }
        }
    }

    /// @dev Encodes `data` using the base64 encoding described in RFC 4648.
    /// Equivalent to `encode(data, false, false)`.
    function encode(bytes memory data) internal pure returns (string memory result) {
        result = encode(data, false, false);
    }

    /// @dev Encodes `data` using the base64 encoding described in RFC 4648.
    /// Equivalent to `encode(data, fileSafe, false)`.
    function encode(bytes memory data, bool fileSafe)
        internal
        pure
        returns (string memory result)
    {
        result = encode(data, fileSafe, false);
    }

    /// @dev Encodes base64 encoded `data`.
    ///
    /// Supports:
    /// - RFC 4648 (both standard and file-safe mode).
    /// - RFC 3501 (63: ',').
    ///
    /// Does not support:
    /// - Line breaks.
    ///
    /// Note: For performance reasons,
    /// this function will NOT revert on invalid `data` inputs.
    /// Outputs for invalid inputs will simply be undefined behaviour.
    /// It is the user's responsibility to ensure that the `data`
    /// is a valid base64 encoded string.
    function decode(string memory data) internal pure returns (bytes memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            let dataLength := mload(data)

            if dataLength {
                let decodedLength := mul(shr(2, dataLength), 3)

                for {} 1 {} {
                    // If padded.
                    if iszero(and(dataLength, 3)) {
                        let t := xor(mload(add(data, dataLength)), 0x3d3d)
                        // forgefmt: disable-next-item
                        decodedLength := sub(
                            decodedLength,
                            add(iszero(byte(30, t)), iszero(byte(31, t)))
                        )
                        break
                    }
                    // If non-padded.
                    decodedLength := add(decodedLength, sub(and(dataLength, 3), 1))
                    break
                }
                result := mload(0x40)

                // Write the length of the bytes.
                mstore(result, decodedLength)

                // Skip the first slot, which stores the length.
                let ptr := add(result, 0x20)
                let end := add(ptr, decodedLength)

                // Load the table into the scratch space.
                // Constants are optimized for smaller bytecode with zero gas overhead.
                // `m` also doubles as the mask of the upper 6 bits.
                let m := 0xfc000000fc00686c7074787c8084888c9094989ca0a4a8acb0b4b8bcc0c4c8cc
                mstore(0x5b, m)
                mstore(0x3b, 0x04080c1014181c2024282c3034383c4044484c5054585c6064)
                mstore(0x1a, 0xf8fcf800fcd0d4d8dce0e4e8ecf0f4)

                for {} 1 {} {
                    // Read 4 bytes.
                    data := add(data, 4)
                    let input := mload(data)

                    // Write 3 bytes.
                    // forgefmt: disable-next-item
                    mstore(ptr, or(
                        and(m, mload(byte(28, input))),
                        shr(6, or(
                            and(m, mload(byte(29, input))),
                            shr(6, or(
                                and(m, mload(byte(30, input))),
                                shr(6, mload(byte(31, input)))
                            ))
                        ))
                    ))

                    ptr := add(ptr, 3)

                    if iszero(lt(ptr, end)) { break }
                }

                // Allocate the memory for the string.
                // Add 31 and mask with `not(31)` to round the
                // free memory pointer up the next multiple of 32.
                mstore(0x40, and(add(end, 31), not(31)))
                // Zeroize the slot after the bytes.
                mstore(end, 0)
                // Restore the zero slot.
                mstore(0x60, 0)
            }
        }
    }
}

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

import { ERC721 } from "solmate/tokens/ERC721.sol";
import { SSTORE2 } from "solady/utils/SSTORE2.sol";
import { Base64 } from "solady/utils/Base64.sol";
import { LibString } from "solady/utils/LibString.sol";

/**
 * @title CounterFacts™
 * @author emo.eth
 * @notice A contract for minting and revealing CounterFacts™: the fun,
 *         collectible way to prove you're right!
 *
 *         CounterFacts™ are ERC721 tokens that are pointers to data
 *         contracts containing the text of a prediction. Did we mention that
 *         the contract might not actually exist?
 *         Upon minting a CounterFact™, the creator supplies the deterministic
 *         counterfactual address of this data contract. Anyone can then
 *         reveal the text by providing the original data + salt to the reveal
 *         function. The data contract will be deployed to the same address,
 *         and the token will be updated to display the text the data contract
 *         contains.
 */
contract CounterFacts is ERC721(unicode"CounterFacts™", "COUNTER") {
    error ContractExists();
    error IncorrectStorageAddress();
    error DuplicateCounterFact();
    error TokenDoesNotExist(uint256 tokenId);

    event MetadataUpdate(uint256 _tokenId);

    struct DataContract {
        address dataContract;
        bool deployed;
    }

    uint256 public nextTokenId;
    mapping(uint256 tokenId => address creator) public creators;
    mapping(uint256 tokenId => DataContract dataContract) internal
        _dataContracts;
    mapping(address dataContract => uint256 tokenId) public
        dataContractToTokenId;

    /**
     * @notice Mint a new CounterFact™ by providing the deterministic address
     * of its contents (must currently be empty).
     */
    function mint(address dataContract) public returns (uint256 tokenId) {
        // this can be inaccurate if called during the constructor of
        // dataContract, so also store a boolean flag when actually deployed
        // by reveal()
        if (dataContract.code.length > 0) {
            revert ContractExists();
        }
        if (dataContractToTokenId[dataContract] != 0) {
            revert DuplicateCounterFact();
        }
        // Increment tokenId before minting to avoid tokenId 0
        tokenId = ++nextTokenId;
        // store the creator
        creators[tokenId] = msg.sender;
        // store the counterfactual contract address
        _dataContracts[tokenId] =
            DataContract({ dataContract: dataContract, deployed: false });
        // store the tokenId in the reverse mapping
        dataContractToTokenId[dataContract] = tokenId;
        _mint(msg.sender, tokenId);
    }

    /**
     * @notice Reveal the contents of a CounterFact™ by providing the data and
     *         salt that were used to generate the deterministic address used to
     *         mint it.
     */
    function reveal(uint256 tokenId, string calldata data, bytes32 salt)
        public
    {
        if (_ownerOf[tokenId] == address(0)) {
            revert TokenDoesNotExist(tokenId);
        }
        address deployed = SSTORE2.writeDeterministic(bytes(data), salt);
        DataContract memory dataContract = _dataContracts[tokenId];
        // check that the deployed address matches the counterfactual address
        if (deployed != dataContract.dataContract) {
            revert IncorrectStorageAddress();
        }
        _dataContracts[tokenId].deployed = true;
        // signal that the metadata has been updated
        emit MetadataUpdate(tokenId);
    }

    /**
     * @notice Convenience method to determine the deterministic address of a
     *         CounterFact™'s contents. Note that you will be exposing the
     *         contents of the CounterFact™ to the RPC provider.
     */
    function predict(string calldata data, bytes32 salt)
        public
        view
        returns (address)
    {
        return SSTORE2.predictDeterministicAddress(
            bytes(data), salt, address(this)
        );
    }

    /**
     * @notice Get the URI for a CounterFact™'s metadata.
     */
    function tokenURI(uint256 tokenId)
        public
        view
        override
        returns (string memory)
    {
        return string.concat(
            "data:application/json;base64,",
            Base64.encode(bytes(stringURI(tokenId)))
        );
    }

    /**
     * @notice Get the string URI for a CounterFact™'s metadata, for
     * convenience.
     */
    function stringURI(uint256 tokenId) public view returns (string memory) {
        if (_ownerOf[tokenId] == address(0)) {
            revert TokenDoesNotExist(tokenId);
        }
        string memory escapedString;

        DataContract memory dataContractStruct = _dataContracts[tokenId];
        address dataContract = dataContractStruct.dataContract;
        if (dataContract.code.length > 0) {
            if (dataContractStruct.deployed) {
                // escape HTML to avoid embedding of non-text content
                // escape JSON to avoid breaking the JSON
                escapedString = LibString.escapeJSON(
                    LibString.escapeHTML(string(SSTORE2.read(dataContract)))
                );
            } else {
                escapedString = "data:text/plain,Very sneaky!";
                return string.concat(
                    '{"animation_url":"',
                    escapedString,
                    '","attributes":[{"trait_type":"Creator","value":"',
                    "The Sneakooooor",
                    '"},{"trait_type":"Data Contract","value":"',
                    LibString.toHexString(dataContract),
                    '"}, {"trait_type":"Sneaky","value":"Yes',
                    '"}]}'
                );
            }
        } else {
            escapedString = "This CounterFact has not yet been revealed.";
        }
        escapedString = string.concat("data:text/plain,", escapedString);
        return string.concat(
            '{"animation_url":"',
            escapedString,
            '","attributes":[{"trait_type":"Creator","value":"',
            LibString.toHexString(creators[tokenId]),
            '"},{"trait_type":"Data Contract","value":"',
            LibString.toHexString(dataContract),
            '"}]}'
        );
    }

    function getDataContract(uint256 tokenId)
        public
        view
        returns (DataContract memory dataContract)
    {
        return _dataContracts[tokenId];
    }

    function contractURI() public pure returns (string memory) {
        return string.concat(
            "data:application/json;base64,",
            Base64.encode(
                bytes(
                    string.concat(
                        unicode'{"name":"CounterFacts™","description":"Counterfacts™: the fun, collectible way to prove ',
                        unicode"you're right!",
                        '"}'
                    )
                )
            )
        );
    }
}

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity >=0.8.0;

/// @notice Modern, minimalist, and gas efficient ERC-721 implementation.
/// @author Solmate (https://github.com/transmissions11/solmate/blob/main/src/tokens/ERC721.sol)
abstract contract ERC721 {
    /*//////////////////////////////////////////////////////////////
                                 EVENTS
    //////////////////////////////////////////////////////////////*/

    event Transfer(address indexed from, address indexed to, uint256 indexed id);

    event Approval(address indexed owner, address indexed spender, uint256 indexed id);

    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /*//////////////////////////////////////////////////////////////
                         METADATA STORAGE/LOGIC
    //////////////////////////////////////////////////////////////*/

    string public name;

    string public symbol;

    function tokenURI(uint256 id) public view virtual returns (string memory);

    /*//////////////////////////////////////////////////////////////
                      ERC721 BALANCE/OWNER STORAGE
    //////////////////////////////////////////////////////////////*/

    mapping(uint256 => address) internal _ownerOf;

    mapping(address => uint256) internal _balanceOf;

    function ownerOf(uint256 id) public view virtual returns (address owner) {
        require((owner = _ownerOf[id]) != address(0), "NOT_MINTED");
    }

    function balanceOf(address owner) public view virtual returns (uint256) {
        require(owner != address(0), "ZERO_ADDRESS");

        return _balanceOf[owner];
    }

    /*//////////////////////////////////////////////////////////////
                         ERC721 APPROVAL STORAGE
    //////////////////////////////////////////////////////////////*/

    mapping(uint256 => address) public getApproved;

    mapping(address => mapping(address => bool)) public isApprovedForAll;

    /*//////////////////////////////////////////////////////////////
                               CONSTRUCTOR
    //////////////////////////////////////////////////////////////*/

    constructor(string memory _name, string memory _symbol) {
        name = _name;
        symbol = _symbol;
    }

    /*//////////////////////////////////////////////////////////////
                              ERC721 LOGIC
    //////////////////////////////////////////////////////////////*/

    function approve(address spender, uint256 id) public virtual {
        address owner = _ownerOf[id];

        require(msg.sender == owner || isApprovedForAll[owner][msg.sender], "NOT_AUTHORIZED");

        getApproved[id] = spender;

        emit Approval(owner, spender, id);
    }

    function setApprovalForAll(address operator, bool approved) public virtual {
        isApprovedForAll[msg.sender][operator] = approved;

        emit ApprovalForAll(msg.sender, operator, approved);
    }

    function transferFrom(
        address from,
        address to,
        uint256 id
    ) public virtual {
        require(from == _ownerOf[id], "WRONG_FROM");

        require(to != address(0), "INVALID_RECIPIENT");

        require(
            msg.sender == from || isApprovedForAll[from][msg.sender] || msg.sender == getApproved[id],
            "NOT_AUTHORIZED"
        );

        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        unchecked {
            _balanceOf[from]--;

            _balanceOf[to]++;
        }

        _ownerOf[id] = to;

        delete getApproved[id];

        emit Transfer(from, to, id);
    }

    function safeTransferFrom(
        address from,
        address to,
        uint256 id
    ) public virtual {
        transferFrom(from, to, id);

        require(
            to.code.length == 0 ||
                ERC721TokenReceiver(to).onERC721Received(msg.sender, from, id, "") ==
                ERC721TokenReceiver.onERC721Received.selector,
            "UNSAFE_RECIPIENT"
        );
    }

    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        bytes calldata data
    ) public virtual {
        transferFrom(from, to, id);

        require(
            to.code.length == 0 ||
                ERC721TokenReceiver(to).onERC721Received(msg.sender, from, id, data) ==
                ERC721TokenReceiver.onERC721Received.selector,
            "UNSAFE_RECIPIENT"
        );
    }

    /*//////////////////////////////////////////////////////////////
                              ERC165 LOGIC
    //////////////////////////////////////////////////////////////*/

    function supportsInterface(bytes4 interfaceId) public view virtual returns (bool) {
        return
            interfaceId == 0x01ffc9a7 || // ERC165 Interface ID for ERC165
            interfaceId == 0x80ac58cd || // ERC165 Interface ID for ERC721
            interfaceId == 0x5b5e139f; // ERC165 Interface ID for ERC721Metadata
    }

    /*//////////////////////////////////////////////////////////////
                        INTERNAL MINT/BURN LOGIC
    //////////////////////////////////////////////////////////////*/

    function _mint(address to, uint256 id) internal virtual {
        require(to != address(0), "INVALID_RECIPIENT");

        require(_ownerOf[id] == address(0), "ALREADY_MINTED");

        // Counter overflow is incredibly unrealistic.
        unchecked {
            _balanceOf[to]++;
        }

        _ownerOf[id] = to;

        emit Transfer(address(0), to, id);
    }

    function _burn(uint256 id) internal virtual {
        address owner = _ownerOf[id];

        require(owner != address(0), "NOT_MINTED");

        // Ownership check above ensures no underflow.
        unchecked {
            _balanceOf[owner]--;
        }

        delete _ownerOf[id];

        delete getApproved[id];

        emit Transfer(owner, address(0), id);
    }

    /*//////////////////////////////////////////////////////////////
                        INTERNAL SAFE MINT LOGIC
    //////////////////////////////////////////////////////////////*/

    function _safeMint(address to, uint256 id) internal virtual {
        _mint(to, id);

        require(
            to.code.length == 0 ||
                ERC721TokenReceiver(to).onERC721Received(msg.sender, address(0), id, "") ==
                ERC721TokenReceiver.onERC721Received.selector,
            "UNSAFE_RECIPIENT"
        );
    }

    function _safeMint(
        address to,
        uint256 id,
        bytes memory data
    ) internal virtual {
        _mint(to, id);

        require(
            to.code.length == 0 ||
                ERC721TokenReceiver(to).onERC721Received(msg.sender, address(0), id, data) ==
                ERC721TokenReceiver.onERC721Received.selector,
            "UNSAFE_RECIPIENT"
        );
    }
}

/// @notice A generic interface for a contract which properly accepts ERC721 tokens.
/// @author Solmate (https://github.com/transmissions11/solmate/blob/main/src/tokens/ERC721.sol)
abstract contract ERC721TokenReceiver {
    function onERC721Received(
        address,
        address,
        uint256,
        bytes calldata
    ) external virtual returns (bytes4) {
        return ERC721TokenReceiver.onERC721Received.selector;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

/// @notice Library for converting numbers into strings and other string operations.
/// @author Solady (https://github.com/vectorized/solady/blob/main/src/utils/LibString.sol)
/// @author Modified from Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/LibString.sol)
library LibString {
    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                        CUSTOM ERRORS                       */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev The `length` of the output is too small to contain all the hex digits.
    error HexLengthInsufficient();

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                         CONSTANTS                          */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev The constant returned when the `search` is not found in the string.
    uint256 internal constant NOT_FOUND = type(uint256).max;

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                     DECIMAL OPERATIONS                     */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns the base 10 decimal representation of `value`.
    function toString(uint256 value) internal pure returns (string memory str) {
        /// @solidity memory-safe-assembly
        assembly {
            // The maximum value of a uint256 contains 78 digits (1 byte per digit), but
            // we allocate 0xa0 bytes to keep the free memory pointer 32-byte word aligned.
            // We will need 1 word for the trailing zeros padding, 1 word for the length,
            // and 3 words for a maximum of 78 digits.
            str := add(mload(0x40), 0x80)
            // Update the free memory pointer to allocate.
            mstore(0x40, add(str, 0x20))
            // Zeroize the slot after the string.
            mstore(str, 0)

            // Cache the end of the memory to calculate the length later.
            let end := str

            let w := not(0) // Tsk.
            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            for { let temp := value } 1 {} {
                str := add(str, w) // `sub(str, 1)`.
                // Write the character to the pointer.
                // The ASCII index of the '0' character is 48.
                mstore8(str, add(48, mod(temp, 10)))
                // Keep dividing `temp` until zero.
                temp := div(temp, 10)
                if iszero(temp) { break }
            }

            let length := sub(end, str)
            // Move the pointer 32 bytes leftwards to make room for the length.
            str := sub(str, 0x20)
            // Store the length.
            mstore(str, length)
        }
    }

    /// @dev Returns the base 10 decimal representation of `value`.
    function toString(int256 value) internal pure returns (string memory str) {
        if (value >= 0) {
            return toString(uint256(value));
        }
        unchecked {
            str = toString(uint256(-value));
        }
        /// @solidity memory-safe-assembly
        assembly {
            // We still have some spare memory space on the left,
            // as we have allocated 3 words (96 bytes) for up to 78 digits.
            let length := mload(str) // Load the string length.
            mstore(str, 0x2d) // Store the '-' character.
            str := sub(str, 1) // Move back the string pointer by a byte.
            mstore(str, add(length, 1)) // Update the string length.
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   HEXADECIMAL OPERATIONS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns the hexadecimal representation of `value`,
    /// left-padded to an input length of `length` bytes.
    /// The output is prefixed with "0x" encoded using 2 hexadecimal digits per byte,
    /// giving a total length of `length * 2 + 2` bytes.
    /// Reverts if `length` is too small for the output to contain all the digits.
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(value, length);
        /// @solidity memory-safe-assembly
        assembly {
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(str, 0x3078) // Write the "0x" prefix.
            str := sub(str, 2) // Move the pointer.
            mstore(str, strLength) // Write the length.
        }
    }

    /// @dev Returns the hexadecimal representation of `value`,
    /// left-padded to an input length of `length` bytes.
    /// The output is prefixed with "0x" encoded using 2 hexadecimal digits per byte,
    /// giving a total length of `length * 2` bytes.
    /// Reverts if `length` is too small for the output to contain all the digits.
    function toHexStringNoPrefix(uint256 value, uint256 length)
        internal
        pure
        returns (string memory str)
    {
        /// @solidity memory-safe-assembly
        assembly {
            // We need 0x20 bytes for the trailing zeros padding, `length * 2` bytes
            // for the digits, 0x02 bytes for the prefix, and 0x20 bytes for the length.
            // We add 0x20 to the total and round down to a multiple of 0x20.
            // (0x20 + 0x20 + 0x02 + 0x20) = 0x62.
            str := add(mload(0x40), and(add(shl(1, length), 0x42), not(0x1f)))
            // Allocate the memory.
            mstore(0x40, add(str, 0x20))
            // Zeroize the slot after the string.
            mstore(str, 0)

            // Cache the end to calculate the length later.
            let end := str
            // Store "0123456789abcdef" in scratch space.
            mstore(0x0f, 0x30313233343536373839616263646566)

            let start := sub(str, add(length, length))
            let w := not(1) // Tsk.
            let temp := value
            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            for {} 1 {} {
                str := add(str, w) // `sub(str, 2)`.
                mstore8(add(str, 1), mload(and(temp, 15)))
                mstore8(str, mload(and(shr(4, temp), 15)))
                temp := shr(8, temp)
                if iszero(xor(str, start)) { break }
            }

            if temp {
                // Store the function selector of `HexLengthInsufficient()`.
                mstore(0x00, 0x2194895a)
                // Revert with (offset, size).
                revert(0x1c, 0x04)
            }

            // Compute the string's length.
            let strLength := sub(end, str)
            // Move the pointer and write the length.
            str := sub(str, 0x20)
            mstore(str, strLength)
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is prefixed with "0x" and encoded using 2 hexadecimal digits per byte.
    /// As address are 20 bytes long, the output will left-padded to have
    /// a length of `20 * 2 + 2` bytes.
    function toHexString(uint256 value) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(value);
        /// @solidity memory-safe-assembly
        assembly {
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(str, 0x3078) // Write the "0x" prefix.
            str := sub(str, 2) // Move the pointer.
            mstore(str, strLength) // Write the length.
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is encoded using 2 hexadecimal digits per byte.
    /// As address are 20 bytes long, the output will left-padded to have
    /// a length of `20 * 2` bytes.
    function toHexStringNoPrefix(uint256 value) internal pure returns (string memory str) {
        /// @solidity memory-safe-assembly
        assembly {
            // We need 0x20 bytes for the trailing zeros padding, 0x20 bytes for the length,
            // 0x02 bytes for the prefix, and 0x40 bytes for the digits.
            // The next multiple of 0x20 above (0x20 + 0x20 + 0x02 + 0x40) is 0xa0.
            str := add(mload(0x40), 0x80)
            // Allocate the memory.
            mstore(0x40, add(str, 0x20))
            // Zeroize the slot after the string.
            mstore(str, 0)

            // Cache the end to calculate the length later.
            let end := str
            // Store "0123456789abcdef" in scratch space.
            mstore(0x0f, 0x30313233343536373839616263646566)

            let w := not(1) // Tsk.
            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            for { let temp := value } 1 {} {
                str := add(str, w) // `sub(str, 2)`.
                mstore8(add(str, 1), mload(and(temp, 15)))
                mstore8(str, mload(and(shr(4, temp), 15)))
                temp := shr(8, temp)
                if iszero(temp) { break }
            }

            // Compute the string's length.
            let strLength := sub(end, str)
            // Move the pointer and write the length.
            str := sub(str, 0x20)
            mstore(str, strLength)
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is prefixed with "0x", encoded using 2 hexadecimal digits per byte,
    /// and the alphabets are capitalized conditionally according to
    /// https://eips.ethereum.org/EIPS/eip-55
    function toHexStringChecksumed(address value) internal pure returns (string memory str) {
        str = toHexString(value);
        /// @solidity memory-safe-assembly
        assembly {
            let mask := shl(6, div(not(0), 255)) // `0b010000000100000000 ...`
            let o := add(str, 0x22)
            let hashed := and(keccak256(o, 40), mul(34, mask)) // `0b10001000 ... `
            let t := shl(240, 136) // `0b10001000 << 240`
            for { let i := 0 } 1 {} {
                mstore(add(i, i), mul(t, byte(i, hashed)))
                i := add(i, 1)
                if eq(i, 20) { break }
            }
            mstore(o, xor(mload(o), shr(1, and(mload(0x00), and(mload(o), mask)))))
            o := add(o, 0x20)
            mstore(o, xor(mload(o), shr(1, and(mload(0x20), and(mload(o), mask)))))
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is prefixed with "0x" and encoded using 2 hexadecimal digits per byte.
    function toHexString(address value) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(value);
        /// @solidity memory-safe-assembly
        assembly {
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(str, 0x3078) // Write the "0x" prefix.
            str := sub(str, 2) // Move the pointer.
            mstore(str, strLength) // Write the length.
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is encoded using 2 hexadecimal digits per byte.
    function toHexStringNoPrefix(address value) internal pure returns (string memory str) {
        /// @solidity memory-safe-assembly
        assembly {
            str := mload(0x40)

            // Allocate the memory.
            // We need 0x20 bytes for the trailing zeros padding, 0x20 bytes for the length,
            // 0x02 bytes for the prefix, and 0x28 bytes for the digits.
            // The next multiple of 0x20 above (0x20 + 0x20 + 0x02 + 0x28) is 0x80.
            mstore(0x40, add(str, 0x80))

            // Store "0123456789abcdef" in scratch space.
            mstore(0x0f, 0x30313233343536373839616263646566)

            str := add(str, 2)
            mstore(str, 40)

            let o := add(str, 0x20)
            mstore(add(o, 40), 0)

            value := shl(96, value)

            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            for { let i := 0 } 1 {} {
                let p := add(o, add(i, i))
                let temp := byte(i, value)
                mstore8(add(p, 1), mload(and(temp, 15)))
                mstore8(p, mload(shr(4, temp)))
                i := add(i, 1)
                if eq(i, 20) { break }
            }
        }
    }

    /// @dev Returns the hex encoded string from the raw bytes.
    /// The output is encoded using 2 hexadecimal digits per byte.
    function toHexString(bytes memory raw) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(raw);
        /// @solidity memory-safe-assembly
        assembly {
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(str, 0x3078) // Write the "0x" prefix.
            str := sub(str, 2) // Move the pointer.
            mstore(str, strLength) // Write the length.
        }
    }

    /// @dev Returns the hex encoded string from the raw bytes.
    /// The output is encoded using 2 hexadecimal digits per byte.
    function toHexStringNoPrefix(bytes memory raw) internal pure returns (string memory str) {
        /// @solidity memory-safe-assembly
        assembly {
            let length := mload(raw)
            str := add(mload(0x40), 2) // Skip 2 bytes for the optional prefix.
            mstore(str, add(length, length)) // Store the length of the output.

            // Store "0123456789abcdef" in scratch space.
            mstore(0x0f, 0x30313233343536373839616263646566)

            let o := add(str, 0x20)
            let end := add(raw, length)

            for {} iszero(eq(raw, end)) {} {
                raw := add(raw, 1)
                mstore8(add(o, 1), mload(and(mload(raw), 15)))
                mstore8(o, mload(and(shr(4, mload(raw)), 15)))
                o := add(o, 2)
            }
            mstore(o, 0) // Zeroize the slot after the string.
            mstore(0x40, and(add(o, 31), not(31))) // Allocate the memory.
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   RUNE STRING OPERATIONS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns the number of UTF characters in the string.
    function runeCount(string memory s) internal pure returns (uint256 result) {
        /// @solidity memory-safe-assembly
        assembly {
            if mload(s) {
                mstore(0x00, div(not(0), 255))
                mstore(0x20, 0x0202020202020202020202020202020202020202020202020303030304040506)
                let o := add(s, 0x20)
                let end := add(o, mload(s))
                for { result := 1 } 1 { result := add(result, 1) } {
                    o := add(o, byte(0, mload(shr(250, mload(o)))))
                    if iszero(lt(o, end)) { break }
                }
            }
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   BYTE STRING OPERATIONS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    // For performance and bytecode compactness, all indices of the following operations
    // are byte (ASCII) offsets, not UTF character offsets.

    /// @dev Returns `subject` all occurrences of `search` replaced with `replacement`.
    function replace(string memory subject, string memory search, string memory replacement)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let subjectLength := mload(subject)
            let searchLength := mload(search)
            let replacementLength := mload(replacement)

            subject := add(subject, 0x20)
            search := add(search, 0x20)
            replacement := add(replacement, 0x20)
            result := add(mload(0x40), 0x20)

            let subjectEnd := add(subject, subjectLength)
            if iszero(gt(searchLength, subjectLength)) {
                let subjectSearchEnd := add(sub(subjectEnd, searchLength), 1)
                let h := 0
                if iszero(lt(searchLength, 32)) { h := keccak256(search, searchLength) }
                let m := shl(3, sub(32, and(searchLength, 31)))
                let s := mload(search)
                for {} 1 {} {
                    let t := mload(subject)
                    // Whether the first `searchLength % 32` bytes of
                    // `subject` and `search` matches.
                    if iszero(shr(m, xor(t, s))) {
                        if h {
                            if iszero(eq(keccak256(subject, searchLength), h)) {
                                mstore(result, t)
                                result := add(result, 1)
                                subject := add(subject, 1)
                                if iszero(lt(subject, subjectSearchEnd)) { break }
                                continue
                            }
                        }
                        // Copy the `replacement` one word at a time.
                        for { let o := 0 } 1 {} {
                            mstore(add(result, o), mload(add(replacement, o)))
                            o := add(o, 0x20)
                            if iszero(lt(o, replacementLength)) { break }
                        }
                        result := add(result, replacementLength)
                        subject := add(subject, searchLength)
                        if searchLength {
                            if iszero(lt(subject, subjectSearchEnd)) { break }
                            continue
                        }
                    }
                    mstore(result, t)
                    result := add(result, 1)
                    subject := add(subject, 1)
                    if iszero(lt(subject, subjectSearchEnd)) { break }
                }
            }

            let resultRemainder := result
            result := add(mload(0x40), 0x20)
            let k := add(sub(resultRemainder, result), sub(subjectEnd, subject))
            // Copy the rest of the string one word at a time.
            for {} lt(subject, subjectEnd) {} {
                mstore(resultRemainder, mload(subject))
                resultRemainder := add(resultRemainder, 0x20)
                subject := add(subject, 0x20)
            }
            result := sub(result, 0x20)
            // Zeroize the slot after the string.
            let last := add(add(result, 0x20), k)
            mstore(last, 0)
            // Allocate memory for the length and the bytes,
            // rounded up to a multiple of 32.
            mstore(0x40, and(add(last, 31), not(31)))
            // Store the length of the result.
            mstore(result, k)
        }
    }

    /// @dev Returns the byte index of the first location of `search` in `subject`,
    /// searching from left to right, starting from `from`.
    /// Returns `NOT_FOUND` (i.e. `type(uint256).max`) if the `search` is not found.
    function indexOf(string memory subject, string memory search, uint256 from)
        internal
        pure
        returns (uint256 result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            for { let subjectLength := mload(subject) } 1 {} {
                if iszero(mload(search)) {
                    if iszero(gt(from, subjectLength)) {
                        result := from
                        break
                    }
                    result := subjectLength
                    break
                }
                let searchLength := mload(search)
                let subjectStart := add(subject, 0x20)

                result := not(0) // Initialize to `NOT_FOUND`.

                subject := add(subjectStart, from)
                let end := add(sub(add(subjectStart, subjectLength), searchLength), 1)

                let m := shl(3, sub(32, and(searchLength, 31)))
                let s := mload(add(search, 0x20))

                if iszero(and(lt(subject, end), lt(from, subjectLength))) { break }

                if iszero(lt(searchLength, 32)) {
                    for { let h := keccak256(add(search, 0x20), searchLength) } 1 {} {
                        if iszero(shr(m, xor(mload(subject), s))) {
                            if eq(keccak256(subject, searchLength), h) {
                                result := sub(subject, subjectStart)
                                break
                            }
                        }
                        subject := add(subject, 1)
                        if iszero(lt(subject, end)) { break }
                    }
                    break
                }
                for {} 1 {} {
                    if iszero(shr(m, xor(mload(subject), s))) {
                        result := sub(subject, subjectStart)
                        break
                    }
                    subject := add(subject, 1)
                    if iszero(lt(subject, end)) { break }
                }
                break
            }
        }
    }

    /// @dev Returns the byte index of the first location of `search` in `subject`,
    /// searching from left to right.
    /// Returns `NOT_FOUND` (i.e. `type(uint256).max`) if the `search` is not found.
    function indexOf(string memory subject, string memory search)
        internal
        pure
        returns (uint256 result)
    {
        result = indexOf(subject, search, 0);
    }

    /// @dev Returns the byte index of the first location of `search` in `subject`,
    /// searching from right to left, starting from `from`.
    /// Returns `NOT_FOUND` (i.e. `type(uint256).max`) if the `search` is not found.
    function lastIndexOf(string memory subject, string memory search, uint256 from)
        internal
        pure
        returns (uint256 result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            for {} 1 {} {
                result := not(0) // Initialize to `NOT_FOUND`.
                let searchLength := mload(search)
                if gt(searchLength, mload(subject)) { break }
                let w := result

                let fromMax := sub(mload(subject), searchLength)
                if iszero(gt(fromMax, from)) { from := fromMax }

                let end := add(add(subject, 0x20), w)
                subject := add(add(subject, 0x20), from)
                if iszero(gt(subject, end)) { break }
                // As this function is not too often used,
                // we shall simply use keccak256 for smaller bytecode size.
                for { let h := keccak256(add(search, 0x20), searchLength) } 1 {} {
                    if eq(keccak256(subject, searchLength), h) {
                        result := sub(subject, add(end, 1))
                        break
                    }
                    subject := add(subject, w) // `sub(subject, 1)`.
                    if iszero(gt(subject, end)) { break }
                }
                break
            }
        }
    }

    /// @dev Returns the byte index of the first location of `search` in `subject`,
    /// searching from right to left.
    /// Returns `NOT_FOUND` (i.e. `type(uint256).max`) if the `search` is not found.
    function lastIndexOf(string memory subject, string memory search)
        internal
        pure
        returns (uint256 result)
    {
        result = lastIndexOf(subject, search, uint256(int256(-1)));
    }

    /// @dev Returns whether `subject` starts with `search`.
    function startsWith(string memory subject, string memory search)
        internal
        pure
        returns (bool result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let searchLength := mload(search)
            // Just using keccak256 directly is actually cheaper.
            // forgefmt: disable-next-item
            result := and(
                iszero(gt(searchLength, mload(subject))),
                eq(
                    keccak256(add(subject, 0x20), searchLength),
                    keccak256(add(search, 0x20), searchLength)
                )
            )
        }
    }

    /// @dev Returns whether `subject` ends with `search`.
    function endsWith(string memory subject, string memory search)
        internal
        pure
        returns (bool result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let searchLength := mload(search)
            let subjectLength := mload(subject)
            // Whether `search` is not longer than `subject`.
            let withinRange := iszero(gt(searchLength, subjectLength))
            // Just using keccak256 directly is actually cheaper.
            // forgefmt: disable-next-item
            result := and(
                withinRange,
                eq(
                    keccak256(
                        // `subject + 0x20 + max(subjectLength - searchLength, 0)`.
                        add(add(subject, 0x20), mul(withinRange, sub(subjectLength, searchLength))),
                        searchLength
                    ),
                    keccak256(add(search, 0x20), searchLength)
                )
            )
        }
    }

    /// @dev Returns `subject` repeated `times`.
    function repeat(string memory subject, uint256 times)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let subjectLength := mload(subject)
            if iszero(or(iszero(times), iszero(subjectLength))) {
                subject := add(subject, 0x20)
                result := mload(0x40)
                let output := add(result, 0x20)
                for {} 1 {} {
                    // Copy the `subject` one word at a time.
                    for { let o := 0 } 1 {} {
                        mstore(add(output, o), mload(add(subject, o)))
                        o := add(o, 0x20)
                        if iszero(lt(o, subjectLength)) { break }
                    }
                    output := add(output, subjectLength)
                    times := sub(times, 1)
                    if iszero(times) { break }
                }
                // Zeroize the slot after the string.
                mstore(output, 0)
                // Store the length.
                let resultLength := sub(output, add(result, 0x20))
                mstore(result, resultLength)
                // Allocate memory for the length and the bytes,
                // rounded up to a multiple of 32.
                mstore(0x40, add(result, and(add(resultLength, 63), not(31))))
            }
        }
    }

    /// @dev Returns a copy of `subject` sliced from `start` to `end` (exclusive).
    /// `start` and `end` are byte offsets.
    function slice(string memory subject, uint256 start, uint256 end)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let subjectLength := mload(subject)
            if iszero(gt(subjectLength, end)) { end := subjectLength }
            if iszero(gt(subjectLength, start)) { start := subjectLength }
            if lt(start, end) {
                result := mload(0x40)
                let resultLength := sub(end, start)
                mstore(result, resultLength)
                subject := add(subject, start)
                let w := not(31)
                // Copy the `subject` one word at a time, backwards.
                for { let o := and(add(resultLength, 31), w) } 1 {} {
                    mstore(add(result, o), mload(add(subject, o)))
                    o := add(o, w) // `sub(o, 0x20)`.
                    if iszero(o) { break }
                }
                // Zeroize the slot after the string.
                mstore(add(add(result, 0x20), resultLength), 0)
                // Allocate memory for the length and the bytes,
                // rounded up to a multiple of 32.
                mstore(0x40, add(result, and(add(resultLength, 63), w)))
            }
        }
    }

    /// @dev Returns a copy of `subject` sliced from `start` to the end of the string.
    /// `start` is a byte offset.
    function slice(string memory subject, uint256 start)
        internal
        pure
        returns (string memory result)
    {
        result = slice(subject, start, uint256(int256(-1)));
    }

    /// @dev Returns all the indices of `search` in `subject`.
    /// The indices are byte offsets.
    function indicesOf(string memory subject, string memory search)
        internal
        pure
        returns (uint256[] memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let subjectLength := mload(subject)
            let searchLength := mload(search)

            if iszero(gt(searchLength, subjectLength)) {
                subject := add(subject, 0x20)
                search := add(search, 0x20)
                result := add(mload(0x40), 0x20)

                let subjectStart := subject
                let subjectSearchEnd := add(sub(add(subject, subjectLength), searchLength), 1)
                let h := 0
                if iszero(lt(searchLength, 32)) { h := keccak256(search, searchLength) }
                let m := shl(3, sub(32, and(searchLength, 31)))
                let s := mload(search)
                for {} 1 {} {
                    let t := mload(subject)
                    // Whether the first `searchLength % 32` bytes of
                    // `subject` and `search` matches.
                    if iszero(shr(m, xor(t, s))) {
                        if h {
                            if iszero(eq(keccak256(subject, searchLength), h)) {
                                subject := add(subject, 1)
                                if iszero(lt(subject, subjectSearchEnd)) { break }
                                continue
                            }
                        }
                        // Append to `result`.
                        mstore(result, sub(subject, subjectStart))
                        result := add(result, 0x20)
                        // Advance `subject` by `searchLength`.
                        subject := add(subject, searchLength)
                        if searchLength {
                            if iszero(lt(subject, subjectSearchEnd)) { break }
                            continue
                        }
                    }
                    subject := add(subject, 1)
                    if iszero(lt(subject, subjectSearchEnd)) { break }
                }
                let resultEnd := result
                // Assign `result` to the free memory pointer.
                result := mload(0x40)
                // Store the length of `result`.
                mstore(result, shr(5, sub(resultEnd, add(result, 0x20))))
                // Allocate memory for result.
                // We allocate one more word, so this array can be recycled for {split}.
                mstore(0x40, add(resultEnd, 0x20))
            }
        }
    }

    /// @dev Returns a arrays of strings based on the `delimiter` inside of the `subject` string.
    function split(string memory subject, string memory delimiter)
        internal
        pure
        returns (string[] memory result)
    {
        uint256[] memory indices = indicesOf(subject, delimiter);
        /// @solidity memory-safe-assembly
        assembly {
            let w := not(31)
            let indexPtr := add(indices, 0x20)
            let indicesEnd := add(indexPtr, shl(5, add(mload(indices), 1)))
            mstore(add(indicesEnd, w), mload(subject))
            mstore(indices, add(mload(indices), 1))
            let prevIndex := 0
            for {} 1 {} {
                let index := mload(indexPtr)
                mstore(indexPtr, 0x60)
                if iszero(eq(index, prevIndex)) {
                    let element := mload(0x40)
                    let elementLength := sub(index, prevIndex)
                    mstore(element, elementLength)
                    // Copy the `subject` one word at a time, backwards.
                    for { let o := and(add(elementLength, 31), w) } 1 {} {
                        mstore(add(element, o), mload(add(add(subject, prevIndex), o)))
                        o := add(o, w) // `sub(o, 0x20)`.
                        if iszero(o) { break }
                    }
                    // Zeroize the slot after the string.
                    mstore(add(add(element, 0x20), elementLength), 0)
                    // Allocate memory for the length and the bytes,
                    // rounded up to a multiple of 32.
                    mstore(0x40, add(element, and(add(elementLength, 63), w)))
                    // Store the `element` into the array.
                    mstore(indexPtr, element)
                }
                prevIndex := add(index, mload(delimiter))
                indexPtr := add(indexPtr, 0x20)
                if iszero(lt(indexPtr, indicesEnd)) { break }
            }
            result := indices
            if iszero(mload(delimiter)) {
                result := add(indices, 0x20)
                mstore(result, sub(mload(indices), 2))
            }
        }
    }

    /// @dev Returns a concatenated string of `a` and `b`.
    /// Cheaper than `string.concat()` and does not de-align the free memory pointer.
    function concat(string memory a, string memory b)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let w := not(31)
            result := mload(0x40)
            let aLength := mload(a)
            // Copy `a` one word at a time, backwards.
            for { let o := and(add(mload(a), 32), w) } 1 {} {
                mstore(add(result, o), mload(add(a, o)))
                o := add(o, w) // `sub(o, 0x20)`.
                if iszero(o) { break }
            }
            let bLength := mload(b)
            let output := add(result, mload(a))
            // Copy `b` one word at a time, backwards.
            for { let o := and(add(bLength, 32), w) } 1 {} {
                mstore(add(output, o), mload(add(b, o)))
                o := add(o, w) // `sub(o, 0x20)`.
                if iszero(o) { break }
            }
            let totalLength := add(aLength, bLength)
            let last := add(add(result, 0x20), totalLength)
            // Zeroize the slot after the string.
            mstore(last, 0)
            // Stores the length.
            mstore(result, totalLength)
            // Allocate memory for the length and the bytes,
            // rounded up to a multiple of 32.
            mstore(0x40, and(add(last, 31), w))
        }
    }

    /// @dev Returns a copy of the string in either lowercase or UPPERCASE.
    function toCase(string memory subject, bool toUpper)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let length := mload(subject)
            if length {
                result := add(mload(0x40), 0x20)
                subject := add(subject, 1)
                let flags := shl(add(70, shl(5, toUpper)), 67108863)
                let w := not(0)
                for { let o := length } 1 {} {
                    o := add(o, w)
                    let b := and(0xff, mload(add(subject, o)))
                    mstore8(add(result, o), xor(b, and(shr(b, flags), 0x20)))
                    if iszero(o) { break }
                }
                // Restore the result.
                result := mload(0x40)
                // Stores the string length.
                mstore(result, length)
                // Zeroize the slot after the string.
                let last := add(add(result, 0x20), length)
                mstore(last, 0)
                // Allocate memory for the length and the bytes,
                // rounded up to a multiple of 32.
                mstore(0x40, and(add(last, 31), not(31)))
            }
        }
    }

    /// @dev Returns a lowercased copy of the string.
    function lower(string memory subject) internal pure returns (string memory result) {
        result = toCase(subject, false);
    }

    /// @dev Returns an UPPERCASED copy of the string.
    function upper(string memory subject) internal pure returns (string memory result) {
        result = toCase(subject, true);
    }

    /// @dev Escapes the string to be used within HTML tags.
    function escapeHTML(string memory s) internal pure returns (string memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            for {
                let end := add(s, mload(s))
                result := add(mload(0x40), 0x20)
                // Store the bytes of the packed offsets and strides into the scratch space.
                // `packed = (stride << 5) | offset`. Max offset is 20. Max stride is 6.
                mstore(0x1f, 0x900094)
                mstore(0x08, 0xc0000000a6ab)
                // Store "&quot;&amp;&#39;&lt;&gt;" into the scratch space.
                mstore(0x00, shl(64, 0x2671756f743b26616d703b262333393b266c743b2667743b))
            } iszero(eq(s, end)) {} {
                s := add(s, 1)
                let c := and(mload(s), 0xff)
                // Not in `["\"","'","&","<",">"]`.
                if iszero(and(shl(c, 1), 0x500000c400000000)) {
                    mstore8(result, c)
                    result := add(result, 1)
                    continue
                }
                let t := shr(248, mload(c))
                mstore(result, mload(and(t, 31)))
                result := add(result, shr(5, t))
            }
            let last := result
            // Zeroize the slot after the string.
            mstore(last, 0)
            // Restore the result to the start of the free memory.
            result := mload(0x40)
            // Store the length of the result.
            mstore(result, sub(last, add(result, 0x20)))
            // Allocate memory for the length and the bytes,
            // rounded up to a multiple of 32.
            mstore(0x40, and(add(last, 31), not(31)))
        }
    }

    /// @dev Escapes the string to be used within double-quotes in a JSON.
    function escapeJSON(string memory s) internal pure returns (string memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            for {
                let end := add(s, mload(s))
                result := add(mload(0x40), 0x20)
                // Store "\\u0000" in scratch space.
                // Store "0123456789abcdef" in scratch space.
                // Also, store `{0x08:"b", 0x09:"t", 0x0a:"n", 0x0c:"f", 0x0d:"r"}`.
                // into the scratch space.
                mstore(0x15, 0x5c75303030303031323334353637383961626364656662746e006672)
                // Bitmask for detecting `["\"","\\"]`.
                let e := or(shl(0x22, 1), shl(0x5c, 1))
            } iszero(eq(s, end)) {} {
                s := add(s, 1)
                let c := and(mload(s), 0xff)
                if iszero(lt(c, 0x20)) {
                    if iszero(and(shl(c, 1), e)) {
                        // Not in `["\"","\\"]`.
                        mstore8(result, c)
                        result := add(result, 1)
                        continue
                    }
                    mstore8(result, 0x5c) // "\\".
                    mstore8(add(result, 1), c)
                    result := add(result, 2)
                    continue
                }
                if iszero(and(shl(c, 1), 0x3700)) {
                    // Not in `["\b","\t","\n","\f","\d"]`.
                    mstore8(0x1d, mload(shr(4, c))) // Hex value.
                    mstore8(0x1e, mload(and(c, 15))) // Hex value.
                    mstore(result, mload(0x19)) // "\\u00XX".
                    result := add(result, 6)
                    continue
                }
                mstore8(result, 0x5c) // "\\".
                mstore8(add(result, 1), mload(add(c, 8)))
                result := add(result, 2)
            }
            let last := result
            // Zeroize the slot after the string.
            mstore(last, 0)
            // Restore the result to the start of the free memory.
            result := mload(0x40)
            // Store the length of the result.
            mstore(result, sub(last, add(result, 0x20)))
            // Allocate memory for the length and the bytes,
            // rounded up to a multiple of 32.
            mstore(0x40, and(add(last, 31), not(31)))
        }
    }

    /// @dev Returns whether `a` equals `b`.
    function eq(string memory a, string memory b) internal pure returns (bool result) {
        assembly {
            result := eq(keccak256(add(a, 0x20), mload(a)), keccak256(add(b, 0x20), mload(b)))
        }
    }

    /// @dev Packs a single string with its length into a single word.
    /// Returns `bytes32(0)` if the length is zero or greater than 31.
    function packOne(string memory a) internal pure returns (bytes32 result) {
        /// @solidity memory-safe-assembly
        assembly {
            // We don't need to zero right pad the string,
            // since this is our own custom non-standard packing scheme.
            result :=
                mul(
                    // Load the length and the bytes.
                    mload(add(a, 0x1f)),
                    // `length != 0 && length < 32`. Abuses underflow.
                    // Assumes that the length is valid and within the block gas limit.
                    lt(sub(mload(a), 1), 0x1f)
                )
        }
    }

    /// @dev Unpacks a string packed using {packOne}.
    /// Returns the empty string if `packed` is `bytes32(0)`.
    /// If `packed` is not an output of {packOne}, the output behaviour is undefined.
    function unpackOne(bytes32 packed) internal pure returns (string memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            // Grab the free memory pointer.
            result := mload(0x40)
            // Allocate 2 words (1 for the length, 1 for the bytes).
            mstore(0x40, add(result, 0x40))
            // Zeroize the length slot.
            mstore(result, 0)
            // Store the length and bytes.
            mstore(add(result, 0x1f), packed)
            // Right pad with zeroes.
            mstore(add(add(result, 0x20), mload(result)), 0)
        }
    }

    /// @dev Packs two strings with their lengths into a single word.
    /// Returns `bytes32(0)` if combined length is zero or greater than 30.
    function packTwo(string memory a, string memory b) internal pure returns (bytes32 result) {
        /// @solidity memory-safe-assembly
        assembly {
            let aLength := mload(a)
            // We don't need to zero right pad the strings,
            // since this is our own custom non-standard packing scheme.
            result :=
                mul(
                    // Load the length and the bytes of `a` and `b`.
                    or(
                        shl(shl(3, sub(0x1f, aLength)), mload(add(a, aLength))),
                        mload(sub(add(b, 0x1e), aLength))
                    ),
                    // `totalLength != 0 && totalLength < 31`. Abuses underflow.
                    // Assumes that the lengths are valid and within the block gas limit.
                    lt(sub(add(aLength, mload(b)), 1), 0x1e)
                )
        }
    }

    /// @dev Unpacks strings packed using {packTwo}.
    /// Returns the empty strings if `packed` is `bytes32(0)`.
    /// If `packed` is not an output of {packTwo}, the output behaviour is undefined.
    function unpackTwo(bytes32 packed)
        internal
        pure
        returns (string memory resultA, string memory resultB)
    {
        /// @solidity memory-safe-assembly
        assembly {
            // Grab the free memory pointer.
            resultA := mload(0x40)
            resultB := add(resultA, 0x40)
            // Allocate 2 words for each string (1 for the length, 1 for the byte). Total 4 words.
            mstore(0x40, add(resultB, 0x40))
            // Zeroize the length slots.
            mstore(resultA, 0)
            mstore(resultB, 0)
            // Store the lengths and bytes.
            mstore(add(resultA, 0x1f), packed)
            mstore(add(resultB, 0x1f), mload(add(add(resultA, 0x20), mload(resultA))))
            // Right pad with zeroes.
            mstore(add(add(resultA, 0x20), mload(resultA)), 0)
            mstore(add(add(resultB, 0x20), mload(resultB)), 0)
        }
    }

    /// @dev Directly returns `a` without copying.
    function directReturn(string memory a) internal pure {
        assembly {
            // Assumes that the string does not start from the scratch space.
            let retStart := sub(a, 0x20)
            let retSize := add(mload(a), 0x40)
            // Right pad with zeroes. Just in case the string is produced
            // by a method that doesn't zero right pad.
            mstore(add(retStart, retSize), 0)
            // Store the return offset.
            mstore(retStart, 0x20)
            // End the transaction, returning the string.
            return(retStart, retSize)
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

/// @notice Read and write to persistent storage at a fraction of the cost.
/// @author Solady (https://github.com/vectorized/solmady/blob/main/src/utils/SSTORE2.sol)
/// @author Saw-mon-and-Natalie (https://github.com/Saw-mon-and-Natalie)
/// @author Modified from Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/SSTORE2.sol)
/// @author Modified from 0xSequence (https://github.com/0xSequence/sstore2/blob/master/contracts/SSTORE2.sol)
library SSTORE2 {
    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                         CONSTANTS                          */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev We skip the first byte as it's a STOP opcode,
    /// which ensures the contract can't be called.
    uint256 internal constant DATA_OFFSET = 1;

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                        CUSTOM ERRORS                       */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Unable to deploy the storage contract.
    error DeploymentFailed();

    /// @dev The storage contract address is invalid.
    error InvalidPointer();

    /// @dev Attempt to read outside of the storage contract's bytecode bounds.
    error ReadOutOfBounds();

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                         WRITE LOGIC                        */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Writes `data` into the bytecode of a storage contract and returns its address.
    function write(bytes memory data) internal returns (address pointer) {
        /// @solidity memory-safe-assembly
        assembly {
            let originalDataLength := mload(data)

            // Add 1 to data size since we are prefixing it with a STOP opcode.
            let dataSize := add(originalDataLength, DATA_OFFSET)

            /**
             * ------------------------------------------------------------------------------+
             * Opcode      | Mnemonic        | Stack                   | Memory              |
             * ------------------------------------------------------------------------------|
             * 61 codeSize | PUSH2 codeSize  | codeSize                |                     |
             * 80          | DUP1            | codeSize codeSize       |                     |
             * 60 0xa      | PUSH1 0xa       | 0xa codeSize codeSize   |                     |
             * 3D          | RETURNDATASIZE  | 0 0xa codeSize codeSize |                     |
             * 39          | CODECOPY        | codeSize                | [0..codeSize): code |
             * 3D          | RETURNDATASZIE  | 0 codeSize              | [0..codeSize): code |
             * F3          | RETURN          |                         | [0..codeSize): code |
             * 00          | STOP            |                         |                     |
             * ------------------------------------------------------------------------------+
             * @dev Prefix the bytecode with a STOP opcode to ensure it cannot be called.
             * Also PUSH2 is used since max contract size cap is 24,576 bytes which is less than 2 ** 16.
             */
            mstore(
                data,
                or(
                    0x61000080600a3d393df300,
                    // Left shift `dataSize` by 64 so that it lines up with the 0000 after PUSH2.
                    shl(0x40, dataSize)
                )
            )

            // Deploy a new contract with the generated creation code.
            pointer := create(0, add(data, 0x15), add(dataSize, 0xa))

            // If `pointer` is zero, revert.
            if iszero(pointer) {
                // Store the function selector of `DeploymentFailed()`.
                mstore(0x00, 0x30116425)
                // Revert with (offset, size).
                revert(0x1c, 0x04)
            }

            // Restore original length of the variable size `data`.
            mstore(data, originalDataLength)
        }
    }

    /// @dev Writes `data` into the bytecode of a storage contract with `salt`
    /// and returns its deterministic address.
    function writeDeterministic(bytes memory data, bytes32 salt)
        internal
        returns (address pointer)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let originalDataLength := mload(data)
            let dataSize := add(originalDataLength, DATA_OFFSET)

            mstore(data, or(0x61000080600a3d393df300, shl(0x40, dataSize)))

            // Deploy a new contract with the generated creation code.
            pointer := create2(0, add(data, 0x15), add(dataSize, 0xa), salt)

            // If `pointer` is zero, revert.
            if iszero(pointer) {
                // Store the function selector of `DeploymentFailed()`.
                mstore(0x00, 0x30116425)
                // Revert with (offset, size).
                revert(0x1c, 0x04)
            }

            // Restore original length of the variable size `data`.
            mstore(data, originalDataLength)
        }
    }

    /// @dev Returns the initialization code hash of the storage contract for `data`.
    /// Used for mining vanity addresses with create2crunch.
    function initCodeHash(bytes memory data) internal pure returns (bytes32 hash) {
        /// @solidity memory-safe-assembly
        assembly {
            let originalDataLength := mload(data)
            let dataSize := add(originalDataLength, DATA_OFFSET)

            mstore(data, or(0x61000080600a3d393df300, shl(0x40, dataSize)))

            hash := keccak256(add(data, 0x15), add(dataSize, 0xa))

            // Restore original length of the variable size `data`.
            mstore(data, originalDataLength)
        }
    }

    /// @dev Returns the address of the storage contract for `data`
    /// deployed with `salt` by `deployer`.
    function predictDeterministicAddress(bytes memory data, bytes32 salt, address deployer)
        internal
        pure
        returns (address predicted)
    {
        bytes32 hash = initCodeHash(data);
        /// @solidity memory-safe-assembly
        assembly {
            // Compute and store the bytecode hash.
            mstore8(0x00, 0xff) // Write the prefix.
            mstore(0x35, hash)
            mstore(0x01, shl(96, deployer))
            mstore(0x15, salt)
            predicted := keccak256(0x00, 0x55)
            // Restore the part of the free memory pointer that has been overwritten.
            mstore(0x35, 0)
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                         READ LOGIC                         */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns all the `data` from the bytecode of the storage contract at `pointer`.
    function read(address pointer) internal view returns (bytes memory data) {
        /// @solidity memory-safe-assembly
        assembly {
            let pointerCodesize := extcodesize(pointer)
            if iszero(pointerCodesize) {
                // Store the function selector of `InvalidPointer()`.
                mstore(0x00, 0x11052bb4)
                // Revert with (offset, size).
                revert(0x1c, 0x04)
            }
            // Offset all indices by 1 to skip the STOP opcode.
            let size := sub(pointerCodesize, DATA_OFFSET)

            // Get the pointer to the free memory and allocate
            // enough 32-byte words for the data and the length of the data,
            // then copy the code to the allocated memory.
            // Masking with 0xffe0 will suffice, since contract size is less than 16 bits.
            data := mload(0x40)
            mstore(0x40, add(data, and(add(size, 0x3f), 0xffe0)))
            mstore(data, size)
            mstore(add(add(data, 0x20), size), 0) // Zeroize the last slot.
            extcodecopy(pointer, add(data, 0x20), DATA_OFFSET, size)
        }
    }

    /// @dev Returns the `data` from the bytecode of the storage contract at `pointer`,
    /// from the byte at `start`, to the end of the data stored.
    function read(address pointer, uint256 start) internal view returns (bytes memory data) {
        /// @solidity memory-safe-assembly
        assembly {
            let pointerCodesize := extcodesize(pointer)
            if iszero(pointerCodesize) {
                // Store the function selector of `InvalidPointer()`.
                mstore(0x00, 0x11052bb4)
                // Revert with (offset, size).
                revert(0x1c, 0x04)
            }

            // If `!(pointer.code.size > start)`, reverts.
            // This also handles the case where `start + DATA_OFFSET` overflows.
            if iszero(gt(pointerCodesize, start)) {
                // Store the function selector of `ReadOutOfBounds()`.
                mstore(0x00, 0x84eb0dd1)
                // Revert with (offset, size).
                revert(0x1c, 0x04)
            }
            let size := sub(pointerCodesize, add(start, DATA_OFFSET))

            // Get the pointer to the free memory and allocate
            // enough 32-byte words for the data and the length of the data,
            // then copy the code to the allocated memory.
            // Masking with 0xffe0 will suffice, since contract size is less than 16 bits.
            data := mload(0x40)
            mstore(0x40, add(data, and(add(size, 0x3f), 0xffe0)))
            mstore(data, size)
            mstore(add(add(data, 0x20), size), 0) // Zeroize the last slot.
            extcodecopy(pointer, add(data, 0x20), add(start, DATA_OFFSET), size)
        }
    }

    /// @dev Returns the `data` from the bytecode of the storage contract at `pointer`,
    /// from the byte at `start`, to the byte at `end` (exclusive) of the data stored.
    function read(address pointer, uint256 start, uint256 end)
        internal
        view
        returns (bytes memory data)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let pointerCodesize := extcodesize(pointer)
            if iszero(pointerCodesize) {
                // Store the function selector of `InvalidPointer()`.
                mstore(0x00, 0x11052bb4)
                // Revert with (offset, size).
                revert(0x1c, 0x04)
            }

            // If `!(pointer.code.size > end) || (start > end)`, revert.
            // This also handles the cases where
            // `end + DATA_OFFSET` or `start + DATA_OFFSET` overflows.
            if iszero(
                and(
                    gt(pointerCodesize, end), // Within bounds.
                    iszero(gt(start, end)) // Valid range.
                )
            ) {
                // Store the function selector of `ReadOutOfBounds()`.
                mstore(0x00, 0x84eb0dd1)
                // Revert with (offset, size).
                revert(0x1c, 0x04)
            }
            let size := sub(end, start)

            // Get the pointer to the free memory and allocate
            // enough 32-byte words for the data and the length of the data,
            // then copy the code to the allocated memory.
            // Masking with 0xffe0 will suffice, since contract size is less than 16 bits.
            data := mload(0x40)
            mstore(0x40, add(data, and(add(size, 0x3f), 0xffe0)))
            mstore(data, size)
            mstore(add(add(data, 0x20), size), 0) // Zeroize the last slot.
            extcodecopy(pointer, add(data, 0x20), add(start, DATA_OFFSET), size)
        }
    }
}

{
  "compilationTarget": {
    "src/CounterFacts.sol": "CounterFacts"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "none"
  },
  "optimizer": {
    "enabled": true,
    "runs": 10000000
  },
  "remappings": [
    ":create2-helpers/=lib/create2-helpers/",
    ":create2-scripts/=lib/create2-helpers/script/",
    ":ds-test/=lib/forge-std/lib/ds-test/src/",
    ":forge-std/=lib/forge-std/src/",
    ":openzeppelin-contracts/=lib/openzeppelin-contracts/",
    ":solady/=lib/solady/src/",
    ":solmate/=lib/solmate/src/"
  ]
}