Summary

calculatePixelWidth can be optimized as bytes(text).length can be very large and we have only one "It is further assumed that there is no other semicolon in text".

Vulnerability Details

function calculatePixelWidth(string memory text, bool largeFont) internal pure returns (uint256 width) {
    uint256 length = bytes(text).length;
    if (length == 0) {
        return 0;
    }

    unchecked {
        uint256 charWidth = largeFont ? 16 : 13;
        uint256 semicolonIndex;
        for (uint256 i = 0; i < length; ++i) {
            if (bytes(text)[i] == ";") {
                semicolonIndex = i;
            }
            width += charWidth;
        }

        // Account for escaped characters (such as &#8805;).
  @>>      width -= charWidth * semicolonIndex;
    }
}

Impact

code is optimized as we are not going through the whole array.

Tools Used

Recommendations

function calculatePixelWidth(string memory text, bool largeFont) internal pure returns (uint256 width) {
    uint256 length = bytes(text).length;
    if (length == 0) {
        return 0;
    }

    unchecked {
        uint256 charWidth = largeFont ? 16 : 13;
        uint256 semicolonIndex;
        for (uint256 i = 0; i < length; ++i) {
            if (bytes(text)[i] == ";") {
                semicolonIndex = i;
                 break;

            }
           
        }

        // Account for escaped characters (such as &#8805;).
         width =(length-i)*charWidth;
    }
}