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  1. <?php
  2. class MyClass{
  3.     function bin2dec($bin)
  4.     {
  5.         $length = count($bin) - 1;
  6.         $sum = 0;
  7.         //convert using doubling
  8.         for($i = 0; $i < $length; $i++)
  9.         {
  10.             //use string_add if doubling bigger than int32
  11.             if($i >= 16)
  12.             {
  13.                 $double = $this->string_add("$sum", "$sum");
  14.                 $cr = $bin[$i];
  15.                 if($cr == 0)
  16.                 {
  17.                     $sum = $this->string_add($sum, $double);
  18.                 }
  19.                 else{
  20.                 	return $i;
  21.                     $add = $this->string_add($double, "$cr");
  22.                     $sum = $this->string_add($sum, $add);
  23.                 }
  24.             }
  25.             else{
  26.                 $sum += ($sum * 2) + $bin[$i];
  27.             }
  28.         }
  29.         return $sum;
  30.     }
  31.  
  32.     function string_add($a, $b)
  33.     {
  34.         $lena = strlen($a); $lenb = strlen($b);
  35.         if($lena == $lenb)
  36.         {
  37.             $len = $lena - 1;//any
  38.         }
  39.         else if($lena > $lenb)
  40.         {
  41.             $b = str_pad($b, $lena, "0", STR_PAD_LEFT);
  42.             $len = $lena - 1;
  43.         }
  44.         else if($lenb > $lena){
  45.             $a = str_pad($a, $lenb, "0", STR_PAD_RIGHT);
  46.             $len = $lenb - 1;
  47.         }
  48.         $result = "";
  49.         for ($i = $len, $carry = 0; $i >= 0 || $carry != 0; $i--)
  50.         {
  51.             $add1 = $i < 0 ? 0 : $a[$i];
  52.             $add2 = $i < 0 ? 0 : $b[$i];
  53.             $add = $add1 + $add2 + $carry;
  54.             if ($add > 9) {
  55.                 $carry = 1;
  56.                 $add -= 10;
  57.             }
  58.             else {
  59.                 $carry = 0;
  60.             }
  61.             $result .= $add;
  62.         }
  63.         return strrev($result);
  64.     }
  65. }
  66.  
  67. $man = new MyClass();
  68. $arr = array_pad(array(1), 62, 0);
  69. $dec = $man->bin2dec($arr);
  70. echo $dec;
Success #stdin #stdout 0.01s 20520KB
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118534269812248282176546132235124736
https://ideone.com/kMs2lx
language:
PHP (php 7.3.5)
created:
9 years ago
visibility:
public

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