//SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

library LibUintToString {
    uint256 private constant MAX_UINT256_STRING_LENGTH = 78;
    uint8 private constant ASCII_DIGIT_OFFSET = 48;

    /// @dev Converts a `uint256` value to a string.
    /// @param n The integer to convert.
    /// @return nstr `n` as a decimal string.
    function toString(uint256 n) internal pure returns (string memory nstr) {
        if (n == 0) {
            return '0';
        }
        // Overallocate memory
        nstr = new string(MAX_UINT256_STRING_LENGTH);
        uint256 k = MAX_UINT256_STRING_LENGTH;
        // Populate string from right to left (lsb to msb).
        while (n != 0) {
            assembly {
                let char := add(ASCII_DIGIT_OFFSET, mod(n, 10))
                mstore(add(nstr, k), char)
                k := sub(k, 1)
                n := div(n, 10)
            }
        }
        assembly {
            // Shift pointer over to actual start of string.
            nstr := add(nstr, k)
            // Store actual string length.
            mstore(nstr, sub(MAX_UINT256_STRING_LENGTH, k))
        }
        return nstr;
    }
}