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