JapaneseNumerals.php

<?php

class JapaneseNumerals
{
    const USE_FORMAL = 1;
    const USE_FORMAL_TEN_THOUSAND = 2;

    /**
     @return string          Japanese Numeral
     */
    public static function to($left, $right = null, $flags = 0)
    {
        $numbers = self::getNumbers($flags);
        $zero = self::getZero($flags);
        $quartets = self::getQuartets($flags);

        $string = '';
        $data_array = [];
        $data_string = '';
        $decimal_string = '';

        if ($right != null) {
            $decimal_string = $right;
        }

        $t = (ceil(strlen($left) / 4) * 4) - strlen($left); // Amount of placeholder we're going to need to make the quartets evenly divisible.  This makes it so much easier on us.
        $left = str_repeat('0', $t).$left; // Prepend Zeros to make an Even Amount

        // Make an Array of Each Quartet
        $i = 4;
        while ($i <= strlen($left)) {
            $data_array[] = substr($left, $i * -1, 4);
            $i += 4;
        }

        // Create the Number from the lowest quartet to the highest
        foreach ($data_array as $i => $v) {
            if (intval($v) == 0) {
                continue;
            } // Skip the Quartet if its worthless

            $temp_string = '';

            // Each of the below "Place"s are per-quartet places

            // Ones Place
            $temp_string = $numbers[substr($v, -1, 1)];

            // Tens Place
            if (substr($v, -2, 1) == 1) { // If we have --1-
                $temp_string = $numbers[10].$temp_string;
            } elseif (substr($v, -2, 1) != 0) { // If we have --X-
                $temp_string = $numbers[substr($v, -2, 1)].$numbers[10].$temp_string;
            }

            // Hundreds Place
            if (substr($v, -3, 1) == 1) { // If we have -1--
                $temp_string = $numbers[100].$temp_string;
            } elseif (substr($v, -3, 1) != 0) { // If we have -X--
                $temp_string = $numbers[substr($v, -3, 1)].$numbers[100].$temp_string;
            }

            // Thousands Place
            if (substr($v, -4, 1) == 1) { // If we have 1---
                $temp_string = $numbers[1000].$temp_string;
            } elseif (substr($v, -4, 1) != 0) { // If we have X---
                $temp_string = $numbers[substr($v, -4, 1)].$numbers[1000].$temp_string;
            }

            // Prepend the newest data to string, separating it from the string by the quartet identifier
            $data_string = $temp_string.$quartets[$i].$data_string;
        }

        // If there is no number, our number is zero - of course!
        if ($data_string == '') {
            $data_string = $zero;
        }

        // Now we do the decimal (if we have one)
        if ($decimal_string != '') {
            $decimal_convert = $numbers;
            $decimal_convert[0] = $zero; // Replace the placeholder with Zero here.
            $decimal_string = str_replace([
                '0',
                '1',
                '2',
                '3',
                '4',
                '5',
                '6',
                '7',
                '8',
                '9',
                'x',
            ], // Each number to be replaced.  X is a placeholder for the non-existant 10
                $decimal_convert, $decimal_string);
            // Separate the Left and Right of the decimal using a Japanese Middot
            $data_string = $data_string.'・'.$decimal_string;
        }

        // Finally, Return the number!
        return $data_string;
    }

    /**
     @return string  Arabic Numeral
     */
    public static function from($num)
    {
        $definitionTable = self::getDefinitionTables();
        $numbers = $definitionTable['numbers'];
        $myriads = $definitionTable['myriads'];
        $len = mb_strlen($num);
        $myriad = 0;
        $temp = 1;
        $temp2 = 0;
        $result = '0';
        mb_internal_encoding('UTF-8');
        for ($i = 0;$i < $len;++$i) {
            $parse = self::substr_unicode($num, $i, 1);
            if (isset($numbers[$parse]) && intval($numbers[$parse]) < 10) {
                $temp = intval($numbers[$parse]);
                $temp2 = $temp;
            } elseif (isset($numbers[$parse])) {
                $myriad += $temp * intval($numbers[$parse]);
                $temp = 1;
                $temp2 = 0;
            } else {
                foreach ($myriads as $j => $v) {
                    if (self::substr_unicode($j, 0, 1) == $parse) {
                        $i += mb_strlen($j);
                        if ($myriad == 0) {
                            $myriad = $temp;
                        }
                        $result = bcadd($result, bcmul($myriad, $v));
                        $myriad = 0;
                        $temp = 1;
                        $temp2 = 0;
                        break;
                    }
                }
            }
        }
        $result = bcadd($result, $temp2);
        $result = bcadd($result, $myriad);

        return $result;
    }

    public static function getDefinitionTables()
    {
        $temp = self::getNumbers();
        $temp[0] = self::getZero();
        $numbers = [];
        foreach ($temp as $arabic => $kanji) {
            $numbers[$kanji] = $arabic;
        }
        $numbers['壱'] = '1';
        $numbers['弐'] = '2';
        $numbers['参'] = '3';
        $numbers['拾'] = '10';
        $numbers[self::getZero(1)] = '0';

        $temp = self::getQuartets();
        $quartets = [];
        foreach ($temp as $key => $kanji) {
            if ($kanji == '') {
                continue;
            }
            $quartets[$kanji] = bcpow(10, $key * 4);
        }
        $quartets['萬'] = '10000';

        return ['numbers' => $numbers, 'myriads' => $quartets];
    }

    protected static function getNumbers($flags = 0)
    {
        $numbers = [
            '', // Blank for ease of use.  Going to use Array Index to grab the proper character
            '一', // 1
            '二', // 2
            '三', // 3
            '四', // 4
            '五', // 5
            '六', // 6
            '七', // 7
            '八', // 8
            '九', // 9
            '十', // 10
        ];
        if ($flags & self::USE_FORMAL == self::USE_FORMAL) {
            $numbers[1] = '壱'; // Formal 1
            $numbers[2] = '弐'; // Formal 2
            $numbers[3] = '参'; // Formal 3
            $numbers[10] = '拾'; // Formal 10
        }
        $numbers[100] = '百'; // 100
        $numbers[1000] = '千'; // 1,000
        return $numbers;
    }

    protected static function getZero($flags = 0)
    {
        if ($flags & self::USE_FORMAL == self::USE_FORMAL) {
            return '零';
        } // Formal 0
        return '〇'; // Informal 0
    }

    protected static function getQuartets($flags = 0)
    {
        // Adding to this array should have no negative consequences
        $quartets = [
            '', // Default Quartet has no symbol
            '万', // 10^4
            '億', // 10^8
            '兆', // 10^12
            '京', // 10^16
            '垓', // 10^20
            '秭', // 10^24
            '穣', // 10^28
            '溝', // 10^32
            '澗', // 10^36
            '正', // 10^40
            '載', // 10^44
            '極', // 10^48
            '恒河沙', // 10^52
            '阿僧祇', // 10^56
            '那由他', // 10^60
            '不可思議', // 10^64
            '無量大数', // 10^68 (as high as quartets currently go?)
        ];
        if ($flags & self::USE_FORMAL_TEN_THOUSAND == self::USE_FORMAL_TEN_THOUSAND) {
            $quartets[1] = '萬';
        } // Older formal character for 10,000
        return $quartets;
    }

    final protected static function substr_unicode($str, $s, $l = null)
    {
        return implode('', array_slice(preg_split('//u', $str, -1, PREG_SPLIT_NO_EMPTY), $s, $l));
    }
}