Decode a file with encoded strings

decode.php

<?php
// Decodes files that have a bunch of strings with things like "\x6d" and "\155" and such in them.
// Meat of the code from https://stackoverflow.com/questions/13774215/convert-hex-code-into-readable-string-in-php
// run me like so on command line:
// php decode.php < encoded.php > output.php
function decode_code($code)
{
    return preg_replace_callback('@\\\(x)?([0-9a-f]{2,3})@',
        function ($m) {
            if ($m[1]) {
                $hex = substr($m[2], 0, 2);
                $unhex = chr(hexdec($hex));
                if (strlen($m[2]) > 2) {
                    $unhex .= substr($m[2], 2);
                }
                return $unhex;
            } else {
                return chr(octdec($m[2]));
            }
        }, $code);
}
$file = file_get_contents('php://stdin');
echo decode_code($file);