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