What is the PHP equivalent of MySQL's UNHEX()?

Question

What is the PHP equivalent of MySQL's UNHEX()?

For instance, the following query and PHP function should provide the same value.

SELECT UNHEX(c1) AS unhexed_c1 FROM table;

$unhexed_c1=PHPs_UNHEX_Equivalent($c1);

Answer 1

There's a built-in function called hex2bin if you're running PHP >= 5.4.

Answer 2

It can be done with pack:

$unhexed = pack('H*', $hexstring);

Answer 3

See How to convert hex to string or text in php:

  function unhex($hex) {
    for($i=0;$i<strlen($hex);$i+=2)
       $str .= chr(hexdec(substr($hex,$i,2)));

    return $str;
  }