1: <?php
 2: 
 3: /**
 4:  * @copyright Copyright (c) 2009-2022 ThemeCatcher (https://www.themecatcher.net)
 5:  */
 6: class Quform_Filter_Alpha extends Quform_Filter_Abstract
 7: {
 8:     /**
 9:      * Filter everything from the given value except alphabet characters
10:      *
11:      * If the value provided is not a string, the value will remain unfiltered
12:      *
13:      * @param   string  $value  The value to filter
14:      * @return  string          The filtered value
15:      */
16:     public function filter($value)
17:     {
18:         if ( ! is_string($value)) {
19:             return $value;
20:         }
21: 
22:         $whiteSpace = $this->config('allowWhiteSpace') ? '\s' : '';
23: 
24:         if (Quform::hasPcreUnicodeSupport()) {
25:             // Use native language alphabet
26:             $pattern = '/[^\p{L}' . $whiteSpace . ']/u';
27:         } else {
28:             $pattern = '/[^a-zA-Z' . $whiteSpace . ']/';
29:         }
30: 
31:         return preg_replace($pattern, '', $value);
32:     }
33: 
34:     /**
35:      * Get the default config for this filter
36:      *
37:      * @param   string|null  $key  Get the config by key, if omitted the full config is returned
38:      * @return  array
39:      */
40:     public static function getDefaultConfig($key = null)
41:     {
42:         $config = apply_filters('quform_default_config_filter_alpha', array(
43:             'allowWhiteSpace' => false
44:         ));
45: 
46:         $config['type'] = 'alpha';
47: 
48:         if (Quform::isNonEmptyString($key)) {
49:             return Quform::get($config, $key);
50:         }
51: 
52:         return $config;
53:     }
54: }
55: