<?php


class Crypto {

  public static function bc2bin($num) {

    return self::dec2base($num, 256);
  }

  public static function dec2base($dec, $base, $digits = false) {

    if ($base < 2 || $base > 256) {
      die('Invalid Base: ' . $base);
    }

    bcscale(0);

    $value = '';

    if (!$digits) {
      $digits = self::digits($base);
    }

    while ($dec > $base - 1) {

      $rest  = bcmod($dec, $base);
      $dec   = bcdiv($dec, $base);
      $value = $digits[$rest] . $value;
    }

    $value   = $digits[intval($dec)] . $value;

    return (string) $value;
  }

  public static function base2dec($value, $base, $digits = false) {

    if ($base < 2 || $base > 256) {
      die('Invalid Base: ' . $base);
    }

    bcscale(0);

    if ($base < 37) {
      $value = strtolower($value);
    }
    if (!$digits) {
      $digits = self::digits($base);
    }

    $size = strlen($value);
    $dec = '0';

    for ($loop = 0; $loop < $size; $loop++) {
      $element = strpos($digits, $value[$loop]);
      $power   = bcpow($base, $size - $loop - 1);
      $dec     = bcadd($dec, bcmul($element, $power));
    }

    return (string) $dec;
  }

  public static function digits($base) {

    if ($base > 64) {

      $digits = '';

      for ($loop = 0; $loop < 256; $loop++) {
        $digits .= chr($loop);
      }
    } else {
      $digits = '0123456789abcdefghijklmnopqrstuvwxyz';
      $digits .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ-_';
    }

    $digits = substr($digits, 0, $base);

    return (string)$digits;
  }

  public static function bin2bc($num) {

    return self::base2dec($num, 256);
  }
}