Lang.php
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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