fwolf / base-converter.php

src/BaseConverter/BaseConverter.php

<?php
namespace Fwolf\Util\BaseConverter;

use Fwolf\Base\Singleton\SingleInstanceTrait;

/**
 * Notice: BC Math or GMP extension maybe not loaded, so test cannot cover all.
 *
 * @copyright   Copyright 2006-2016 Fwolf
 * @license     http://opensource.org/licenses/MIT MIT
 */
class BaseConverter implements BaseConverterInterface
{
    use SingleInstanceTrait;


    /**
     * Number to char
     *
     * @var array
     */
    protected $map = [
        '0',
        '1',
        '2',
        '3',
        '4',
        '5',
        '6',
        '7',
        '8',
        '9',
        'a',
        'b',
        'c',
        'd',
        'e',
        'f',
        'g',
        'h',
        'i',
        'j',
        'k',
        'l',
        'm',
        'n',
        'o',
        'p',
        'q',
        'r',
        's',
        't',
        'u',
        'v',
        'w',
        'x',
        'y',
        'z',
        'A',
        'B',
        'C',
        'D',
        'E',
        'F',
        'G',
        'H',
        'I',
        'J',
        'K',
        'L',
        'M',
        'N',
        'O',
        'P',
        'Q',
        'R',
        'S',
        'T',
        'U',
        'V',
        'W',
        'X',
        'Y',
        'Z',
    ];

    /**
     * Char to number
     *
     * @var array
     */
    protected $reverseMap = [
        '0' => 0,
        '1' => 1,
        '2' => 2,
        '3' => 3,
        '4' => 4,
        '5' => 5,
        '6' => 6,
        '7' => 7,
        '8' => 8,
        '9' => 9,
        'a' => 10,
        'b' => 11,
        'c' => 12,
        'd' => 13,
        'e' => 14,
        'f' => 15,
        'g' => 16,
        'h' => 17,
        'i' => 18,
        'j' => 19,
        'k' => 20,
        'l' => 21,
        'm' => 22,
        'n' => 23,
        'o' => 24,
        'p' => 25,
        'q' => 26,
        'r' => 27,
        's' => 28,
        't' => 29,
        'u' => 30,
        'v' => 31,
        'w' => 32,
        'x' => 33,
        'y' => 34,
        'z' => 35,
        'A' => 36,
        'B' => 37,
        'C' => 38,
        'D' => 39,
        'E' => 40,
        'F' => 41,
        'G' => 42,
        'H' => 43,
        'I' => 44,
        'J' => 45,
        'K' => 46,
        'L' => 47,
        'M' => 48,
        'N' => 49,
        'O' => 50,
        'P' => 51,
        'Q' => 52,
        'R' => 53,
        'S' => 54,
        'T' => 55,
        'U' => 56,
        'V' => 57,
        'W' => 58,
        'X' => 59,
        'Y' => 60,
        'Z' => 61,
    ];

    /**
     * Number equal or larger than 100000000000000(1.0E+14) will represent by
     * Scientific Notation(科学记数法), cause base_convert() loose precision.
     * So for larger number, use BC Math or GMP.
     *
     * This array is used to check number string length per base, if string is
     * longer than the array value, it should not use build-in base_convert().
     *
     * @link https://gist.github.com/fwolf/7250392
     */
    protected $safeLengthMap = [
        2  => 46,   //  2^46 = 70368744177664

50% of this comment could be valid code. Did you maybe forget this after debugging?

        3  => 29,   //  3^29 = 68630377364883

50% of this comment could be valid code. Did you maybe forget this after debugging?

        4  => 23,   //  4^23 = 70368744177664

50% of this comment could be valid code. Did you maybe forget this after debugging?

        5  => 20,   //  5^20 = 95367431640625

50% of this comment could be valid code. Did you maybe forget this after debugging?

        6  => 17,   //  6^17 = 16926659444736

50% of this comment could be valid code. Did you maybe forget this after debugging?

        7  => 16,   //  7^16 = 33232930569601

50% of this comment could be valid code. Did you maybe forget this after debugging?

        8  => 15,   //  8^15 = 35184372088832

50% of this comment could be valid code. Did you maybe forget this after debugging?

        9  => 14,   //  9^14 = 22876792454961

50% of this comment could be valid code. Did you maybe forget this after debugging?

        10 => 13,   // 10^13 = 10000000000000

50% of this comment could be valid code. Did you maybe forget this after debugging?

        11 => 13,   // 11^13 = 34522712143931

50% of this comment could be valid code. Did you maybe forget this after debugging?

        12 => 12,   // 12^12 = 8916100448256

50% of this comment could be valid code. Did you maybe forget this after debugging?

        13 => 12,   // 13^12 = 23298085122481

50% of this comment could be valid code. Did you maybe forget this after debugging?

        14 => 12,   // 14^12 = 56693912375296

50% of this comment could be valid code. Did you maybe forget this after debugging?

        15 => 11,   // 15^11 = 8649755859375

50% of this comment could be valid code. Did you maybe forget this after debugging?

        16 => 11,   // 16^11 = 17592186044416

50% of this comment could be valid code. Did you maybe forget this after debugging?

        17 => 11,   // 17^11 = 34271896307633,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        18 => 11,   // 18^11 = 64268410079232,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        19 => 11,   // 19^10 = 6131066257801,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        20 => 10,   // 20^10 = 10240000000000,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        21 => 10,   // 21^10 = 16679880978201,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        22 => 10,   // 22^10 = 26559922791424,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        23 => 10,   // 23^10 = 41426511213649,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        24 => 10,   // 24^10 = 63403380965376,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        25 => 10,   // 25^10 = 95367431640625,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        26 => 9,    // 26^9  = 5429503678976,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        27 => 9,    // 27^9  = 7625597484987,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        28 => 9,    // 28^9  = 10578455953408,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        29 => 9,    // 29^9  = 14507145975869,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        30 => 9,    // 30^9  = 19683000000000,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        31 => 9,    // 31^9  = 26439622160671,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        32 => 9,    // 32^9  = 35184372088832,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        33 => 9,    // 33^9  = 46411484401953,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        34 => 9,    // 34^9  = 60716992766464,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        35 => 9,    // 35^9  = 78815638671875,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        36 => 8,    // 36^8  = 2821109907456,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        37 => 8,    // 37^8  = 3512479453921,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        38 => 8,    // 38^8  = 4347792138496,

56% of this comment could be valid code. Did you maybe forget this after debugging?

        39 => 8,    // 39^8  = 5352009260481,

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        40 => 8,    // 40^8  = 6553600000000,

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        41 => 8,    // 41^8  = 7984925229121,

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        42 => 8,    // 42^8  = 9682651996416,

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        43 => 8,    // 43^8  = 11688200277601,

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        44 => 8,    // 44^8  = 14048223625216,

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        45 => 8,    // 45^8  = 16815125390625,

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        46 => 8,    // 46^8  = 20047612231936,

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        47 => 8,    // 47^8  = 23811286661761,

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        48 => 8,    // 48^8  = 28179280429056,

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        49 => 8,    // 49^8  = 33232930569601,

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        50 => 8,    // 50^8  = 39062500000000,

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        51 => 8,    // 51^8  = 45767944570401,

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        52 => 8,    // 52^8  = 53459728531456,

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        53 => 8,    // 53^8  = 62259690411361,

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        54 => 8,    // 54^8  = 72301961339136,

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        55 => 8,    // 55^8  = 83733937890625,

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        56 => 8,    // 56^8  = 96717311574016,

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        57 => 7,    // 57^7  = 1954897493193,

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        58 => 7,    // 58^7  = 2207984167552,

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        59 => 7,    // 59^7  = 2488651484819,

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        60 => 7,    // 60^7  = 2799360000000,

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        61 => 7,    // 61^7  = 3142742836021,

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        62 => 7,    // 62^7  = 3521614606208,

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    ];


    /**
     * {@inheritdoc}
     *
     * @throws  \InvalidArgumentException
     * @throws  \Exception
     */
    public function convert($number, $fromBase, $toBase)
    {
        $min = min($fromBase, $toBase);
        $max = max($fromBase, $toBase);
        if (2 > $min || 62 < $max) {
            throw new \InvalidArgumentException('Base must between 2 and 62.');
        }


        $number = trim((string)$number);
        if (empty($number)) {
            return '0';
        }


        // Simple convert use build-in base_convert()
        if (36 >= $fromBase && 36 >= $toBase &&
            strlen($number) <= $this->safeLengthMap[$fromBase]
        ) {
            return strtolower(base_convert($number, $fromBase, $toBase));
        }


        $number = ltrim($number, '0');  // GMP treat leading 0 different.

        // Convert using BC Math or GMP, preferred GMP which is faster
        // In PHP 5.3.2, gmp base was extended to 2~62
        if (extension_loaded('gmp')) {
            return $this->convertWithGmp($number, $fromBase, $toBase);

        } elseif (extension_loaded('bcmath')) {
            return $this->convertWithBcmath($number, $fromBase, $toBase);

        } else {
            throw new \Exception(
                'Number too large and BC Math or GMP not loaded.'
            );
        }
    }


    /**
     * Convert number string base using BC Math
     *
     * @param   string $number
     * @param   int    $fromBase
     * @param   int    $toBase
     * @return  string
     */
    protected function convertWithBcmath($number, $fromBase, $toBase)
    {
        if (10 == $fromBase) {
            $base10 = $number;
        } else {
            $base10 = 0;
            for ($i = 0, $j = strlen($number); $i < $j; $i++) {
                $num = $this->reverseMap[$number{$i}];
                $base10 = bcadd($num, bcmul($base10, $fromBase));
            }
        }

        if (10 == $toBase) {
            return $base10;
        } else {
            $baseN = '';
            while (0 < bccomp($base10, '0', 0)) {
                $remainder = intval(bcmod($base10, $toBase));
                $baseN = $this->map[$remainder] . $baseN;
                $base10 = bcdiv($base10, $toBase, 0);
            }

            return $baseN;
        }
    }


    /**
     * Convert number string base using GMP gmp_strval()
     *
     * @param   string $number
     * @param   int    $fromBase
     * @param   int    $toBase
     * @return  string
     */
    protected function convertWithGmp($number, $fromBase, $toBase)
    {
        // GMP use 0-9a-z for base 11~36, and 0-9A-Za-z for base 37~62, so we
        // need swap upper and lower case.
        // @link http://stackoverflow.com/questions/2259666
        if (36 < $fromBase) {
            $number = strtolower($number) ^ strtoupper($number) ^ $number;
        }

        $number = gmp_strval(gmp_init($number, $fromBase), $toBase);

        if (36 < $toBase) {
            $number = strtolower($number) ^ strtoupper($number) ^ $number;
        }

        return $number;
    }
}