php bccomp的替換函數

if (!function_exists('bccomp')) {

    /**
     * 支援正數和負數的比較
     * ++ -- +-
     * @param $numOne
     * @param $numTwo
     * @param null $scale
     * @return int|string
     */
    function bccomp($numOne, $numTwo, $scale = null)
    {
        //先判斷是傳過來的兩個變量是否合法,不合法都傳回'0'
        if (!preg_match("/^([+-]?)\d+(\.\d+)?$/", $numOne, $numOneSign) ||
            !preg_match("/^([+-]?)\d+(\.\d+)?$/", $numTwo, $numTwoSign)
        ) {
            return '0';
        }

        $signOne = $numOneSign[1] === '-' ? '-' : '+';
        $signTwo = $numTwoSign[1] === '-' ? '-' : '+';

        if ($signOne !== $signTwo) {    //異号
            if ($signOne === '-' && $signTwo === '+') {
                return -1;
            } else if ($signOne === '+' && $signTwo === '-') {
                return 1;
            } else {
                return '0';
            }
        } else {  //同号
            //兩個負數比較
            if ($signOne === "-" && $signTwo === '-') {
                $numOne = abs($numOne);
                $numTwo = abs($numTwo);
                $flag = bccompPositiveNum($numOne, $numTwo, $scale);
                if ($flag === 0) {
                    return 0;
                } else if ($flag === 1) {
                    return -1;
                } else if ($flag === -1) {
                    return 1;
                } else {
                    return '0';
                }
            } else {    //兩個正數比較
                //兩正數比較
                return bccompPositiveNum($numOne, $numTwo, $scale);
            }
        }
    }
}


if (!function_exists('bccompPositiveNum')) {
    /**
     * 比較正數的大小寫問題
     * @param $numOne
     * @param $numTwo
     * @param null $scale
     * @return int|string
     */
    function bccompPositiveNum($numOne, $numTwo, $scale = null)
    {
        // check if they're valid positive numbers, extract the whole numbers and decimals
        if (!preg_match("/^\+?(\d+)(\.\d+)?$/", $numOne, $tmpOne) ||
            !preg_match("/^\+?(\d+)(\.\d+)?$/", $numTwo, $tmpTwo)
        ) {
            return '0';
        }

        // remove leading zeroes from whole numbers
        $numOne = ltrim($tmpOne[1], '0');
        $numTwo = ltrim($tmpTwo[1], '0');

        // first, we can just check the lengths of the numbers, this can help save processing time
        // if $numOne is longer than $numTwo, return 1.. vice versa with the next step.
        if (strlen($numOne) > strlen($numTwo)) {
            return 1;
        } else {
            if (strlen($numOne) < strlen($numTwo)) {
                return -1;
            } // if the two numbers are of equal length, we check digit-by-digit
            else {

                // remove ending zeroes from decimals and remove point
                $Dec1 = isset($tmpOne[2]) ? rtrim(substr($tmpOne[2], 1), '0') : '';
                $Dec2 = isset($tmpTwo[2]) ? rtrim(substr($tmpTwo[2], 1), '0') : '';

                // if the user defined $scale, then make sure we use that only
                if ($scale != null) {
                    $Dec1 = substr($Dec1, 0, $scale);
                    $Dec2 = substr($Dec2, 0, $scale);
                }

                // calculate the longest length of decimals
                $DLen = max(strlen($Dec1), strlen($Dec2));

                // append the padded decimals onto the end of the whole numbers
                $numOne .= str_pad($Dec1, $DLen, '0');
                $numTwo .= str_pad($Dec2, $DLen, '0');

                // check digit-by-digit, if they have a difference, return 1 or -1 (greater/lower than)
                for ($i = 0; $i < strlen($numOne); ++$i) {
                    if ((int)$numOne{$i} > (int)$numTwo{$i}) {
                        return 1;
                    } elseif ((int)$numOne{$i} < (int)$numTwo{$i}) {
                        return -1;
                    }
                }

                // if the two numbers have no difference (they're the same).. return 0
                return 0;
            }
        }
    }
}