1<?php
2
3if (!function_exists('ctype_alpha')) {
4  function ctype_alpha($string)
5  {
6    return preg_match('/^[a-z]+$/i', $string);
7  }
8}
9
10if (!function_exists('ctype_xdigit')) {
11  function ctype_xdigit($string)
12  {
13    return preg_match('/^[0-9a-f]+$/i', $string);
14  }
15}
16
17if (!function_exists('ctype_space')) {
18  function ctype_space($string)
19  {
20    return preg_match('/^[\s]$/', $string);
21  }
22}
23
24?>