ParagonIE_Sodium_Core_Util::compare( string $left, string $right, int $len = null ): int

176    public static function compare($left, $right, $len = null)177    {178        $leftLen = self::strlen($left);179        $rightLen = self::strlen($right);180        if ($len === null) {181            $len = max($leftLen, $rightLen);182            $left = str_pad($left, $len, "\x00", STR_PAD_RIGHT);183            $right = str_pad($right, $len, "\x00", STR_PAD_RIGHT);184        } elseif ($leftLen !== $rightLen) {185            throw new SodiumException("Argument #1 and argument #2 must have the same length");186        }187 188        $gt = 0;189        $eq = 1;190        $i = $len;191        while ($i !== 0) {192            --$i;193            $gt |= ((self::chrToInt($right[$i]) - self::chrToInt($left[$i])) >> 8) & $eq;194            $eq &= ((self::chrToInt($right[$i]) ^ self::chrToInt($left[$i])) - 1) >> 8;195        }196        return ($gt + $gt + $eq) - 1;197    }