<?php
// if want to implement error collecting here, we'll need to use some sort // of global data (probably trigger_error) because it's impossible to pass // $config or $context to the callback functions.
/** * Handles referencing and derefencing character entities */ class HTMLPurifier_EntityParser {
/** * Reference to entity lookup table. */ protected $_entity_lookup;
/** * Callback regex string for parsing entities. */ protected $_substituteEntitiesRegex = '/&(?:[#]x([a-fA-F0-9]+)|[#]0*(\d+)|([A-Za-z_:][A-Za-z0-9.\-_:]*));?/'; // 1. hex 2. dec 3. string (XML style)
/** * Decimal to parsed string conversion table for special entities. */ protected $_special_dec2str = array( 34 => '"', 38 => '&', 39 => "'", 60 => '<', 62 => '>' );
/** * Stripped entity names to decimal conversion table for special entities. */ protected $_special_ent2dec = array( 'quot' => 34, 'amp' => 38, 'lt' => 60, 'gt' => 62 );
/** * Substitutes non-special entities with their parsed equivalents. Since * running this whenever you have parsed character is t3h 5uck, we run * it before everything else. * * @param $string String to have non-special entities parsed. * @returns Parsed string. */ public function substituteNonSpecialEntities($string) { // it will try to detect missing semicolons, but don't rely on it return preg_replace_callback( $this->_substituteEntitiesRegex, array($this, 'nonSpecialEntityCallback'), $string ); }
/** * Callback function for substituteNonSpecialEntities() that does the work. * * @param $matches PCRE matches array, with 0 the entire match, and * either index 1, 2 or 3 set with a hex value, dec value, * or string (respectively). * @returns Replacement string. */
protected function nonSpecialEntityCallback($matches) { // replaces all but big five $entity = $matches[0]; $is_num = (@$matches[0][1] === '#'); if ($is_num) { $is_hex = (@$entity[2] === 'x'); $code = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
// abort for special characters if (isset($this->_special_dec2str[$code])) return $entity;
return HTMLPurifier_Encoder::unichr($code); } else { if (isset($this->_special_ent2dec[$matches[3]])) return $entity; if (!$this->_entity_lookup) { $this->_entity_lookup = HTMLPurifier_EntityLookup::instance(); } if (isset($this->_entity_lookup->table[$matches[3]])) { return $this->_entity_lookup->table[$matches[3]]; } else { return $entity; } } }
/** * Substitutes only special entities with their parsed equivalents. * * @notice We try to avoid calling this function because otherwise, it * would have to be called a lot (for every parsed section). * * @param $string String to have non-special entities parsed. * @returns Parsed string. */ public function substituteSpecialEntities($string) { return preg_replace_callback( $this->_substituteEntitiesRegex, array($this, 'specialEntityCallback'), $string); }
/** * Callback function for substituteSpecialEntities() that does the work. * * This callback has same syntax as nonSpecialEntityCallback(). * * @param $matches PCRE-style matches array, with 0 the entire match, and * either index 1, 2 or 3 set with a hex value, dec value, * or string (respectively). * @returns Replacement string. */ protected function specialEntityCallback($matches) { $entity = $matches[0]; $is_num = (@$matches[0][1] === '#'); if ($is_num) { $is_hex = (@$entity[2] === 'x'); $int = $is_hex ? hexdec($matches[1]) : (int) $matches[2]; return isset($this->_special_dec2str[$int]) ? $this->_special_dec2str[$int] : $entity; } else { return isset($this->_special_ent2dec[$matches[3]]) ? $this->_special_ent2dec[$matches[3]] : $entity; } }
}
// vim: et sw=4 sts=4
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