A function I created to non-recursively get the path of all files and folders including sub-directories of a given folder.
Though I have not tested it completely, it seems to be working.

<?php

/**
 * Finds path, relative to the given root folder, of all files and directories in the given directory and its sub-directories non recursively.
 * Will return an array of the form 
 * array(
 *   'files' => [],
 *   'dirs'  => [],
 * )
 * @author sreekumar
 * @param string $root
 * @result array
 */
function read_all_files($root = '.'){
  $files  = array('files'=>array(), 'dirs'=>array());
  $directories  = array();
  $last_letter  = $root[strlen($root)-1];
  $root  = ($last_letter == '\\' || $last_letter == '/') ? $root : $root.DIRECTORY_SEPARATOR;
  
  $directories[]  = $root;
  
  while (sizeof($directories)) {
    $dir  = array_pop($directories);
    if ($handle = opendir($dir)) {
      while (false !== ($file = readdir($handle))) {
        if ($file == '.' || $file == '..') {
          continue;
        }
        $file  = $dir.$file;
        if (is_dir($file)) {
          $directory_path = $file.DIRECTORY_SEPARATOR;
          array_push($directories, $directory_path);
          $files['dirs'][]  = $directory_path;
        } elseif (is_file($file)) {
          $files['files'][]  = $file;
        }
      }
      closedir($handle);
    }
  }
  
  return $files;
}
?>