Check uploaded file

check_uploaded_file.php

/**
 * Check uploaded file
 *
 * @param string $file file
 * @param int $max_file_length Maximum file length
 * @return bool Return TRUE if Ok, FALSE otherwise.
 */
function _check_upload_filename($file, $max_file_length = 260) {
    $valid_chars_regex = '.A-Z0-9_ !@#$%^&()+={}\[\]\',~`-';
    $file_name = preg_replace('/[^'.$valid_chars_regex.']|\.+$/i', "", basename($file) );
    return ( strlen($file_name) == 0 || strlen($file_name) > $max_file_length ? false : true );
}