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bindec

(PHP 4, PHP 5)

bindecBinary to decimal

Описание

number bindec ( string $binary_string )

Returns the decimal equivalent of the binary number represented by the binary_string argument.

bindec() converts a binary number to an integer or, if needed for size reasons, float.

Список параметров

binary_string

The binary string to convert

Возвращаемые значения

The decimal value of binary_string

Список изменений

Версия Описание
Since 4.1.0 The function can now convert numbers that are too large to fit into the platforms integer type, larger values are returned as float in that case.

Примеры

Пример #1 bindec() example

<?php
echo bindec('110011') . "\n";
echo 
bindec('000110011') . "\n";

echo 
bindec('111');
?>

Результат выполнения данного примера:

51
51
7

Смотрите также


User Contributed Notes
bindec
info at rickdg dot nl
01-Apr-2010 12:40
Two functions to convert 16bit or 8bit binary to integer using two's complement. If input exceeds maximum bits, false is returned. Function is easily scalable to x bits by changing the hexadecimals.

<?php function _bin16dec($bin) {
   
// Function to convert 16bit binary numbers to integers using two's complement
   
$num = bindec($bin);
    if(
$num > 0xFFFF) { return false; }
    if(
$num >= 0x8000) {
        return -((
$num ^ 0xFFFF)+1);
    } else {
        return
$num;
    }
}

function
_bin8dec($bin) {
   
// Function to convert 8bit binary numbers to integers using two's complement
   
$num = bindec($bin);
    if(
$num > 0xFF) { return false; }
    if(
$num >= 0x80) {
        return -((
$num ^ 0xFF)+1);
    } else {
        return
$num;
    }
}
?>
Nitrogen
21-Jul-2009 02:27
Binary to Decimal conversion using the BCMath extension..

<?php

function BCBin2Dec($Input='') {
 
$Output='0';
  if(
preg_match("/^[01]+$/",$Input)) {
    for(
$i=0;$i<strlen($Input);$i++)
     
$Output=BCAdd(BCMul($Output,'2'),$Input{$i});
  }
  return(
$Output);
}

?>

This will simply convert from Base-2 to Base-10 using BCMath (arbitrary precision calculation).

See also: my 'BCDec2Bin' function on the 'decbin' document.
Enjoy,
Nitrogen.
nodarinodo at mail dot ru
08-Jan-2009 07:51
<?php   
// bindecfunc :)))) I think it works well too :)
function bindecc($str)
    {
       
$str = str_replace(" ", "", $str);
       
$strr = preg_match('/[^01]/', $str);
        if(
$strr == 1) { return "<b> Error ! only 1 and 0;</b>"; }
       
$strsig = strlen($str);
       
$strr1 = strrev($str);
       
$strf = '';
        for(
$i = $strsig; $i >= 0; $i--)
        {
           
$strf += ($strr1[$i] * pow(2, $i));
           
#$strf += $str[$i];
       
}
        return
$strf;
    }
?>
flashpack at gmail dot com
16-Nov-2008 12:40
for converting fractions :
eg : 1001.1101

<?php
function BinaryToDecimal($binary){
 
$binary=trim($binary);
  if (
strstr($binary,'.')){
   
$split=explode('.',$binary);
   
$integer=$split[0];
   
$fraction=$split[1];

   
$digits=str_split($fraction);
   
$num=sizeof($digits);
    for (
$i=1; $i<=$num;$i++){
      if (
$digits[$i-1]>1){
        echo
'<script>alert("Enter Binary Digits Only {0,1}\n \n eg: 11001 or 11001.011");history.go(-1)</script> ';
      }
     
$exponent=pow(2,-$i);
     
$fraction_result+=$digits[$i-1]*$exponent;
    }

  }else{
   
$integer=$binary;
  }

 
$splits=str_split($integer);
 
$num=sizeof($splits)-1;
 
$i=$num;
  foreach(
$splits as $digits){
    if (
$digits>1){
      echo
'<script>alert("Enter Binary Digits Only {0,1}\n \n eg: 11001 or 11001.011");history.go(-1)</script> ';
    }
   
$exponent=pow(2,$i);
   
$integer_result+=$digits*$exponent;
   
$i--;
  }
  if(
$fraction_result){
   
$result=$integer_result+$fraction_result;
  }else {
   
$result=$integer_result;
  }
  return
$result ;
}
?>
mashematician at gmail dot com
13-Mar-2008 04:57
A binary to decimal conversion function that takes advantage of the BC library functions to return decimal values of arbitrary length.

Input type must be a string in order to work properly.

<?php

function binary_to_decimal($a) {
   
$bin_array = str_split($a);

   
$y=sizeof($bin_array)-1;
    for (
$x=0; $x<sizeof($bin_array)-1; $x++) {
        if (
$bin_array[$x] == 1) {
           
$bin_array[$x] = bcpow(2, $y);
        }
       
$y--;
    }
   
    for (
$z=0; $z<sizeof($bin_array); $z++) {
       
$result = bcadd($result, $bin_array[$z]);
    }
    echo
$result;
}

binary_to_decimal('11111');

?>
alan hogan dot com slash contact
09-Nov-2007 09:34
The "smartbindec" function I wrote below will convert any binary string (of a reasonable size) to decimal.  It will use two's complement if the leftmost bit is 1, regardless of bit length.  If you are getting unexpected negative answers, try zero-padding your strings with sprintf("%032s", $yourBitString).

<?php
function twoscomp($bin) {
   
$out = "";
   
$mode = "init";
    for(
$x = strlen($bin)-1; $x >= 0; $x--) {
        if (
$mode != "init")
           
$out = ($bin[$x] == "0" ? "1" : "0").$out;
        else {
            if(
$bin[$x] == "1") {
               
$out = "1".$out;
               
$mode = "invert";
            }
            else
               
$out = "0".$out;
        }
    }
    return
$out;
}
function
smartbindec($bin) {
    if(
$bin[0] == 1)
        return -
1 * bindec(twoscomp($bin));
    else return (int)
bindec($bin);
}
?>
gwbdome at freenet dot de
19-Aug-2004 09:43
i think a better method than the "shift-method" is my method ^^...
here it comes:

function convert2bin($string) {
     $finished=0;
     $base=1;
     if(preg_match("/[^0-9]/", $string)) {
         for($i=0; $string!=chr($i); $i++);
         $dec_nr=$i;
     }
     else $dec_nr=$string;
     while($dec_nr>$base) {
         $base=$base*2;
         if($base>$dec_nr) {
             $base=$base/2;
             break;
         }
     }
     while(!$finished) {
         if(($dec_nr-$base)>0) {
             $dec_nr=$dec_nr-$base;
             $bin_nr.=1;
             $base=$base/2;
         }
         elseif(($dec_nr-$base)<0) {
             $bin_nr.=0;
             $base=$base/2;
         }
         elseif(($dec_nr-$base)==0) {
             $bin_nr.=1;
             $finished=1;
             while($base>1) {   
                 $bin_nr.=0;
                 $base=$base/2;
             }
         }
     }
     return $bin_nr;
 }

=====================================================

if you want to reconvert it (from binary to string or integer) you can use this function:

function reconvert($bin_nr) {
     $base=1;
     $dec_nr=0;
     $bin_nr=explode(",", preg_replace("/(.*),/", "$1", str_replace("1", "1,", str_replace("0", "0,", $bin_nr))));
     for($i=1; $i<count($bin_nr); $i++) $base=$base*2;
     foreach($bin_nr as $key=>$bin_nr_bit) {
         if($bin_nr_bit==1) {
             $dec_nr+=$base;
             $base=$base/2;
         }
         if($bin_nr_bit==0) $base=$base/2;
     }
     return(array("string"=>chr($dec_nr), "int"=>$dec_nr));
 }
martin at punix dot de
30-May-2003 05:47
## calculate binary with "shift-method" ##

<?php
function dec2bin($decimal_code){
 for(
$half=($decimal_code);$half>=1;$half=(floor($half))/2){
   if((
$half%2)!=0){
   
$y.=1;
   }
   else{
   
$y.=0;
   }
  }
 
$calculated_bin=strrev($y);
 return
$calculated_bin;
}
?>

## example ##

[bin] 123 = [dec] 1111011

e.g.
123/2 = 61,5 => 1
61/2  = 30,5 => 1
30/2  = 15   => 0
15/2  = 7,5  => 1
7/2   = 3,5  => 1
3/2   = 1,5  => 1
1/2   = 0,5  => 1
(0/2   = 0    finish)
php at silisoftware dot com
01-Mar-2002 03:16
For converting larger-than-31-bit numbers:

<?php
function Bin2Dec($binstring) {
    for (
$i=0;$i<strlen($binstring);$i++) {
       
$decvalue += ((int) substr($binstring, strlen($binstring) - $i - 1, 1)) * pow(2, $i);
    }
    return
$decvalue;
}
?>
 

 
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