<?php

// File: array_compare
// 
// Bi-directional comparison of multi-dimensional arrays.

// Function: array_compare
//
// Crawl through each array to find differences.  This includes differences in
// type (i.e. "2", 2 and 2.0 differ) as well as bits present on one side but
// not on the other.  To catch differences, including those of type, you need
// to use var_dump() on the result; print_r() is too limited.
//
// Discussed at length in the user contributed notes at
// <http://ca.php.net/manual/en/function.array-diff-assoc.php>
//
// This version includes dwraven's replacement of isset() with
// array_key_exists(), as well as a new improvement to allow the comparison of
// non-array arguments.
//
// Returns:
// An array with two elements, one containing what's in your first array, but
// not your second, and the second is vice versa.
//
// License:
// This comes from a group discusson and effort on user notes on php.net.  I
// don't think I can force GPL v3 on this unilaterally.  Therefore, all I can
// say is use/modify this as you'd like, and if you distribute modified
// versions, please keep the mention that our effort on php.net got us this
// far. :-)
function array_compare($array1, $array2) {
	$diff = false;
	if (!is_array($array1) || !is_array($array2)) {
		// We need two arrays, so return non-array comparison.
		if ($array1 !== $array2) $diff = Array($array1, $array2);
		return $diff;
	};
	// Left-to-right
	foreach ($array1 as $key => $value) {
		if (!array_key_exists($key, $array2)) {
			$diff[0][$key] = $value;
		} elseif (is_array($value)) {
			if (!is_array($array2[$key])) {
				$diff[0][$key] = $value;
				$diff[1][$key] = $array2[$key];
			} else {
				$new = array_compare($value, $array2[$key]);
				if ($new !== false) {
					if (isset($new[0])) $diff[0][$key] = $new[0];
					if (isset($new[1])) $diff[1][$key] = $new[1];
				};
			};
		} elseif ($array2[$key] !== $value) {
			$diff[0][$key] = $value;
			$diff[1][$key] = $array2[$key];
		};
	};
	// Right-to-left
	foreach ($array2 as $key => $value) {
		if (!array_key_exists($key, $array1)) {
			$diff[1][$key] = $value;
		};
		// No direct comparsion because matching keys were compared in the
		// left-to-right loop earlier, recursively.
	};
	return $diff;
};

?>