<?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; } } // vim: et sw=4 sts=4