How to fix special character file names issues during file uploads from custom and drupals form.

<?php/** * Last mod : Inder SIngh @ Sat 12 Mart 2:18 AM 2010 */function inders_mod_init() {        //Add any css or js file there        drupal_add_css(drupal_get_path('module', 'inders_mod') .'/inders_mod.css');        //If custom field were used for uploading        //Never prefered        if(!empty($_FILES['avatar_image']) || !empty($_FILES['profile_pic'])){                foreach ($_FILES as $field_name => $field) {                    $_FILES[$field_name]['orig_name']=$field['name'];                    $_FILES[$field_name]['name']=preg_replace('`[^\.a-z0-9]`i','_',$field['name']);            }        }        //This will work for all files if using drupal forms        if (!empty($_FILES['files'])){//Working with global            foreach ($_FILES['files']['name'] as $field => $filename) {                if($field=="diagram"){                    $_FILES['files']['orig_name'][$field] = $filename;//May be useful for some cases                                        //Get the trick to work here                    $_FILES['files']['name'][$field] = preg_replace('`[^\.a-z0-9]`i','_',$filename);                }            }        }}/** * */?>