/modules/purifier/vendor/htmlpurifier/library/HTMLPurifier/AttrDef/Lang.php

<?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

{



    public function validate($string, $config, $context) {



        $string = trim($string);

        if (!$string) return false;



        $subtags = explode('-', $string);

        $num_subtags = count($subtags);



        if ($num_subtags == 0) return false; // sanity check



        // 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;



    }



}



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