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- <?php
- /**
- * Validates the HTML attribute lang, effectively a language code.
- * @note Built according to RFC 3066, which obsoleted RFC 1766
- */
- class HTMLPurifier_AttrDef_Lang extends HTMLPurifier_AttrDef
- {
- /**
- * @param string $string
- * @param HTMLPurifier_Config $config
- * @param HTMLPurifier_Context $context
- * @return bool|string
- */
- public function validate($string, $config, $context)
- {
- $string = trim($string);
- if (!$string) {
- return false;
- }
- $subtags = explode('-', $string);
- $num_subtags = count($subtags);
- if ($num_subtags == 0) { // sanity check
- return false;
- }
- // process primary subtag : $subtags[0]
- $length = strlen($subtags[0]);
- switch ($length) {
- case 0:
- return false;
- case 1:
- if (!($subtags[0] == 'x' || $subtags[0] == 'i')) {
- return false;
- }
- break;
- case 2:
- case 3:
- if (!ctype_alpha($subtags[0])) {
- return false;
- } elseif (!ctype_lower($subtags[0])) {
- $subtags[0] = strtolower($subtags[0]);
- }
- break;
- default:
- return false;
- }
- $new_string = $subtags[0];
- if ($num_subtags == 1) {
- return $new_string;
- }
- // process second subtag : $subtags[1]
- $length = strlen($subtags[1]);
- if ($length == 0 || ($length == 1 && $subtags[1] != 'x') || $length > 8 || !ctype_alnum($subtags[1])) {
- return $new_string;
- }
- if (!ctype_lower($subtags[1])) {
- $subtags[1] = strtolower($subtags[1]);
- }
- $new_string .= '-' . $subtags[1];
- if ($num_subtags == 2) {
- return $new_string;
- }
- // process all other subtags, index 2 and up
- for ($i = 2; $i < $num_subtags; $i++) {
- $length = strlen($subtags[$i]);
- if ($length == 0 || $length > 8 || !ctype_alnum($subtags[$i])) {
- return $new_string;
- }
- if (!ctype_lower($subtags[$i])) {
- $subtags[$i] = strtolower($subtags[$i]);
- }
- $new_string .= '-' . $subtags[$i];
- }
- return $new_string;
- }
- }
- // vim: et sw=4 sts=4
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