The function hex2bin does not exist in PHP5.
You can use 'pack' instead :
$binary_string = pack("H*" , $hex_string);
(PHP >= 5.4.0)
hex2bin — Decodes a hexadecimally encoded binary string
$data
)Decodes a hexadecimally encoded binary string.
This function does NOT convert a hexadecimal number to a binary number. This can be done using the base_convert() function.
dataHexadecimal representation of data.
Returns the binary representation of the given data or FALSE on failure.
If the hexadecimal input string is of odd length or invalid hexadecimal string
an E_WARNING level error is thrown.
| Version | Description |
|---|---|
| 5.5.1 | A warning is thrown if the input string is invalid hexadecimal string. |
| 5.4.4 | A warning is thrown if the input string is of odd length. In PHP 5.4.0 the string was silently accepted, but the last byte was truncated. |
Example #1 hex2bin() example
<?php
$hex = hex2bin("6578616d706c65206865782064617461");
var_dump($hex);
?>
The above example will output something similar to:
string(16) "example hex data"
The function hex2bin does not exist in PHP5.
You can use 'pack' instead :
$binary_string = pack("H*" , $hex_string);
I modified the function by Johnson a bit so it can be used as a drop-in-replacement. You don't need to worry about upgrading php because when it is upgraded, it will use the build in function.
<?php
if ( !function_exists( 'hex2bin' ) ) {
function hex2bin( $str ) {
$sbin = "";
$len = strlen( $str );
for ( $i = 0; $i < $len; $i += 2 ) {
$sbin .= pack( "H*", substr( $str, $i, 2 ) );
}
return $sbin;
}
}
?>
A drop-in hex2bin emulator which behaves just like the the one in v5.5.1.
<?php
if (!function_exists('hex2bin')) {
function hex2bin($data) {
static $old;
if ($old === null) {
$old = version_compare(PHP_VERSION, '5.2', '<');
}
$isobj = false;
if (is_scalar($data) || (($isobj = is_object($data)) && method_exists($data, '__toString'))) {
if ($isobj && $old) {
ob_start();
echo $data;
$data = ob_get_clean();
}
else {
$data = (string) $data;
}
}
else {
trigger_error(__FUNCTION__.'() expects parameter 1 to be string, ' . gettype($data) . ' given', E_USER_WARNING);
return;//null in this case
}
$len = strlen($data);
if ($len % 2) {
trigger_error(__FUNCTION__.'(): Hexadecimal input string must have an even length', E_USER_WARNING);
return false;
}
if (strspn($data, '0123456789abcdefABCDEF') != $len) {
trigger_error(__FUNCTION__.'(): Input string must be hexadecimal string', E_USER_WARNING);
return false;
}
return pack('H*', $data);
}
}
?>
The function pack("H*" , $hex_string); will not work as expected if $hex_string contains an odd number of hexadecimal digits.
For example:
<?php echo ord(pack("H*", 'F')); ?>
will return 240 not 15. Use pack("H*", '0F'); instead.
$test = bin2hex('sample ...');
echo _hex2bin($test);
// another hex2bin replacement
function _hex2bin($result) {
$out = '';
for($c=0;$c<strlen($result);$c+=2) {
$out .= chr(hexdec($result[$c].$result[$c+1]));
} //end for
return (string) $out;
}
Case of an incomplete hex string following function may help:
<?php
function make2validhex($data){
$data = (string) $data;
$len = strlen($data);
if($len % 2) {
return substr($data, 0, $len -1);
}
return $data;
}
?>
test:
<?php
$string="not complete";
echo $string;
echo PHP_EOL;
$hex = bin2hex($string); //"6e6f7420636f6d706c657465"
echo $hex;
echo PHP_EOL;
$deff = substr ($hex, 0, strlen($hex) -1);//"6e6f7420636f6d706c65746"
echo $deff;
echo PHP_EOL;
echo hex2bin(make2validhex($deff)); //"not complet"
echo PHP_EOL;
?>
For those who have php version prior to 5.4, i have a solution to convert hex to binary. It works for me in an encryption and decryption application.
<?php
function hextobin($hexstr)
{
$n = strlen($hexstr);
$sbin="";
$i=0;
while($i<$n)
{
$a =substr($hexstr,$i,2);
$c = pack("H*",$a);
if ($i==0){$sbin=$c;}
else {$sbin.=$c;}
$i+=2;
}
return $sbin;
}
?>
A way to convert hex strings in the form "0x123ABC" to integer is to use the function base_convert("0x123ABC", 16, 10)
Ran into an interesting case with hex2bin and php5.5.12 while upgrading from 5.3.3 -> 5.5.12
The previous code had redeclared the hex2bin function with the $binary_string = pack("H*" , $hex_string) trick.
php5.5.12 would have none of that. The solution, albeit a hacky one, was doing a find an replace of hex2bin to 'hex3bin' for the whole site directory.