[ PHP ] Decodificador Hexadecimal

<title>Decoder by v3n0m</title>
<form method="POST"><center>Introducir codigo hexadecimal: <input type="text" name="hexa"><br>
<input type="submit" name="b1" value="Decodificar">
<?php
// Convertidor de hexadecimal a binario
// tool codeada x v3n0m - 13/02/2009 - 06:05 am
function hexstring($hexstr) {
   $hexstr = str_replace(' ', '', $hexstr);
   $retstr = pack('H*', $hexstr);
   return $retstr;
}
$teststr = $_POST['hexa'];
$b1 = $_POST['b1'];
if($b1){
$str = hexstring($teststr);
echo '<pre>';
echo "Codigo: $teststr\n\n";
echo "Binario: ";
var_dump( $str );
echo "\n";
echo '<br><a href="ascii2.php">Otro code?</a>';
}
?>
<br><br><br>
<code>c0ded by v3n0m (:
</pre>