I needed a recursive function to go through directories and subdirectories, so I headed to PHP.net's readdir() page, knowing that I would find one in user comments. Or did I need a recursive function ? Hell no. I've found the nifty neat following function, which does not recursively calls itself. And what's so cool about it, you may ask ? Speed.
- <?php
- function list_directory($dir) {
- $file_list = '';
- $stack[] = $dir;
- while ($stack) {
- $current_dir = array_pop($stack);
- if ($dh = opendir($current_dir)) {
- while (($file = readdir($dh)) !== false) {
- if ($file !== '.' AND $file !== '..') {
- $current_file = "{$current_dir}/{$file}";
- if (is_file($current_file)) {
- $file_list[] = "{$current_dir}/{$file}";
- } elseif (is_dir($current_file)) {
- $stack[] = $current_file;
- }
- }
- }
- }
- }
- return $file_list;
- }
- ?>
The function returns an array of files from directory passed as argument and subdirectories. The user who submitted this function added a few benchmarks against an average recursive function, to find out that this one is about 50% quicker.
Just as anybody I guess, I've been using various recursive functions for years now, and I just had never thought about why or how to do it differently. Damn. So many CPU cycles wasted for nothing :)
It seems that Microsoft eventually 
