Convert LIRC hex codes to Arduino IR Library Hex Codes

<?php

// ---------------------------------------------------------
// -- A script to convert LIRC remote codes into the
// -- format used by the Ken Sheriff Arduino IR Library
// -- http://www.arcfn.com/2010/12/64-bit-rc6-codes-arduino-and-xbox.html
// ------ Usage --------------------------------------------
// -- Run with:
// -- php -q hexconvert.php 0x37FF07bff
// -- or
// -- php -q hexconvert.php 37FF07bff
// --
// -- It's case insensitive (but always returns lowercase)
// ---------------------------------------------------------

//print_r($argv);

// Is this the input I want? If it is, great, otherwise, end.
if (preg_match("/^[xa-f0-9]+$/i",$argv[1])) {

    // Clean up info, accept both 0x format, and hex without 0x.
    $input = $argv[1];
    $input = preg_replace("/^(0x)?(.+)$/","$2",$input);
    $input = strtolower($input);

    // echo "input: ".$input."\n";

} else {

    echo "did not detect a hexidecimal number in your input\n";
    echo "run like: php -q hexconvert.php 0x0b2FF4 etc\n";
    die("\n");

}

    // Renaming the input, lame.
    $hex = $input;
    // A string of hex digits to reference.
    $hexstr = "0123456789abcdef";

    // The variable where we'll store the result.
    $keep = "";

    // Cycle through all the hex characters in the string.
    for ($i=0; $i<strlen($hex); $i++) {
        // Get the hex character in question.
        $c = substr($hex,$i,1);

        // What's it's decimal value? We get this from the reference string.
        $pos = strpos($hexstr,$c);

        // We invert it's position (that's the whole point of this script)
        $inv = 15 - $pos;

        // And then we string that onto our "keeper" string.
        // echo $c." --> ".$pos." --> ".$inv."\n";
        $keep .= substr($hexstr,$inv,1);
    }

    // And give some output.
    echo "0x".$keep." [Converted to IR Library format]\n";
    echo "0x".$hex." [From your input (from LIRC)]\n";

    echo "\n";


    // Some testing hex values from my MCE remote.
    // x37FF07bff
    /*
            Blue          0x00007ba1
            Yellow        0x00007ba2
            Green         0x00007ba3
            Red           0x00007ba4

    */
    //  $code = 0x37FF07bff; // key ZERO
    //  $code = 0x37FF07bed;
    //  $code = 0x37FF06BFF; // Key 0
    //  $code = 0x37FF08BF3; // Xbox On/Off

?>