array_replace_recursive

WordPress Version: .10

/**
 * PHP-agnostic version of {@link array_replace_recursive()}.
 *
 * The array_replace_recursive() function is a PHP 5.3 function. WordPress
 * currently supports down to PHP 5.2, so this method is a workaround
 * for PHP 5.2.
 *
 * Note: array_replace_recursive() supports infinite arguments, but for our use-
 * case, we only need to support two arguments.
 *
 * Subject to removal once WordPress makes PHP 5.3.0 the minimum requirement.
 *
 * @since 4.5.3
 *
 * @see http://php.net/manual/en/function.array-replace-recursive.php#109390
 *
 * @param  array $base         Array with keys needing to be replaced.
 * @param  array $replacements Array with the replaced keys.
 *
 * @return array
 */
function array_replace_recursive($base = array(), $replacements = array())
{
    foreach (array_slice(func_get_args(), 1) as $replacements) {
        $bref_stack = array(&$base);
        $head_stack = array($replacements);
        do {
            end($bref_stack);
            $bref =& $bref_stack[key($bref_stack)];
            $head = array_pop($head_stack);
            unset($bref_stack[key($bref_stack)]);
            foreach (array_keys($head) as $key) {
                if (isset($key, $bref) && isset($bref[$key]) && is_array($bref[$key]) && isset($head[$key]) && is_array($head[$key])) {
                    $bref_stack[] =& $bref[$key];
                    $head_stack[] = $head[$key];
                } else {
                    $bref[$key] = $head[$key];
                }
            }
        } while (count($head_stack));
    }
    return $base;
}