Recursively replace elements from passed arrays into the first array (safe for PHP 5.2)

safe_array_replace_recursive.php

<?php

/**
 * Recursively replace elements from passed arrays into the first array (safe for PHP 5.2).
 * 
 * @author Frankie Jarrett <fjarrett@gmail.com>
 * @link   http://php.net/manual/en/function.array-replace-recursive.php
 *
 * @param  array $array1
 * @param  array $array2
 * @param  array $...
 *
 * @return array
 */
function safe_array_replace_recursive( array $array1, array $array2 ) {

	if ( function_exists( 'array_replace_recursive' ) ) {
		
		$args = func_get_args();

		return call_user_func_array( 'array_replace_recursive', $args );

	}

	$result = array();

	for ( $i = 0, $total = func_num_args(); $i < $total; $i++ ) {

		$_array = func_get_arg( $i );

		foreach ( $_array as $key => &$value ) {

			if ( is_array( $value ) && isset( $result[ $key ] ) && is_array( $result[ $key ] ) ) {

				$result[ $key ] = call_user_func( __FUNCTION__, $result[ $key ], $value );

				continue;

			}

			$is_assoc = ( array_keys( $_array ) !== range( 0, count( $_array ) - 1 ) );

			if ( ! $is_assoc && ! in_array( $value, $merged, true ) ) {

				$result[] = $value;

				continue;

			}

			$result[ $key ] = $value;

		}

	}

	return (array) $result;

}