presto-spi/src/main/java/io/prestosql/spi/type/Chars.java/Chars/compareUnsignedBytes
class Chars:    private static int compareUnsignedBytes(byte thisByte, byte thatByte)
    {
        return unsignedByteToInt(thisByte) - unsignedByteToInt(thatByte);
    }