#!/usr/bin/php
<?php
# ---------------------------------------------------------------
# xor.php
#   script to xor 2 strings or files
# Usage: 
#   xor [--hex] {-s <str> | -f <fname>} {-s <str> | -f <fname>}
# ---------------------------------------------------------------

# Convert \xAF chars to chr(0xaf)
function parseArgStr($s) {
	return preg_replace("/\\\\x([0-9a-f]{2})/ie", 'chr(0x$1)', $s);
}

# dechex with leading zeroes
function tohex($num, $l = 2) {
	$a = dechex($num);
	while (strlen($a) < $l) $a = "0".$a;
	return $a;
}

# Show message and exit with some code
function halt($message, $exitcode) {
	if ($message) echo rtrim($message, "\r\n")."\n";
	die(intval($exitcode));
}


# ---------------------


$pname = basename(array_shift($argv));
if ($argc < 5) usage();
function usage() {
	global $pname;
	halt("Usage: $pname [--hex] {-s str | -f fname} {-s str | -f fname}\n", 1);
}

function get($type, $var) {
	switch ($type) {
		case "-f": $s = file_get_contents($var); break;
		case "-s": $s = parseArgStr($var); break;
		case "-h": $s = parseHex($var); break;
		default: halt("Error: bad string type.\n", 3);
	}
	return $s;
}

function parseHex($s) {
	$res = '';
	if (strpos($s, ' ') !== false) $hexes = explode(' ', $s);
	else $hexes = str_split($s, 2);
	foreach ($hexes as $hex) {
		$res .= chr(hexdec($hex));
	}
	return $res;
}

$hex = 0;
if ($argv[0] == "--hex") {
	$hex = 1;
	array_shift($argv);
}
if ($argv[0] == "--hex2") {
	$hex = 2;
	array_shift($argv);
}

$s1 = get($argv[0], $argv[1]); //(($argv[0] == '-f') ? file_get_contents($argv[1]) : parseArgStr($argv[1]));
$s2 = get($argv[2], $argv[3]); //(($argv[2] == '-f') ? file_get_contents($argv[3]) : parseArgStr($argv[3]));

for ($i = 0; $i < strlen($s1); $i++) {
	$ch = ord($s1[$i]) ^ ord($s2[$i % strlen($s2)]);
	if ($hex == 1) {echo "\\x".tohex($ch);}
	elseif ($hex == 2) {echo tohex($ch);}
	else {echo chr($ch);}
}
if ($hex) echo "\n"
?>