mirror of
https://github.com/ezyang/htmlpurifier.git
synced 2024-11-14 09:18:41 +00:00
286 lines
9.7 KiB
PHP
286 lines
9.7 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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* @type HTMLPurifier_EntityLookup
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*/
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protected $_entity_lookup;
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/**
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* Callback regex string for entities in text.
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* @type string
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*/
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protected $_textEntitiesRegex;
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/**
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* Callback regex string for entities in attributes.
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* @type string
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*/
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protected $_attrEntitiesRegex;
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/**
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* Tests if the beginning of a string is a semi-optional regex
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*/
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protected $_semiOptionalPrefixRegex;
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public function __construct() {
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// From
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// http://stackoverflow.com/questions/15532252/why-is-reg-being-rendered-as-without-the-bounding-semicolon
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$semi_optional = "quot|QUOT|lt|LT|gt|GT|amp|AMP|AElig|Aacute|Acirc|Agrave|Aring|Atilde|Auml|COPY|Ccedil|ETH|Eacute|Ecirc|Egrave|Euml|Iacute|Icirc|Igrave|Iuml|Ntilde|Oacute|Ocirc|Ograve|Oslash|Otilde|Ouml|REG|THORN|Uacute|Ucirc|Ugrave|Uuml|Yacute|aacute|acirc|acute|aelig|agrave|aring|atilde|auml|brvbar|ccedil|cedil|cent|copy|curren|deg|divide|eacute|ecirc|egrave|eth|euml|frac12|frac14|frac34|iacute|icirc|iexcl|igrave|iquest|iuml|laquo|macr|micro|middot|nbsp|not|ntilde|oacute|ocirc|ograve|ordf|ordm|oslash|otilde|ouml|para|plusmn|pound|raquo|reg|sect|shy|sup1|sup2|sup3|szlig|thorn|times|uacute|ucirc|ugrave|uml|uuml|yacute|yen|yuml";
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// NB: three empty captures to put the fourth match in the right
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// place
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$this->_semiOptionalPrefixRegex = "/&()()()($semi_optional)/";
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$this->_textEntitiesRegex =
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'/&(?:'.
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// hex
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'[#]x([a-fA-F0-9]+);?|'.
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// dec
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'[#]0*(\d+);?|'.
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// string (mandatory semicolon)
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// NB: order matters: match semicolon preferentially
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'([A-Za-z_:][A-Za-z0-9.\-_:]*);|'.
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// string (optional semicolon)
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"($semi_optional)".
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')/';
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$this->_attrEntitiesRegex =
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'/&(?:'.
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// hex
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'[#]x([a-fA-F0-9]+);?|'.
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// dec
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'[#]0*(\d+);?|'.
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// string (mandatory semicolon)
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// NB: order matters: match semicolon preferentially
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'([A-Za-z_:][A-Za-z0-9.\-_:]*);|'.
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// string (optional semicolon)
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// don't match if trailing is equals or alphanumeric (URL
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// like)
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"($semi_optional)(?![=;A-Za-z0-9])".
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')/';
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}
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/**
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* Substitute entities with the parsed equivalents. Use this on
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* textual data in an HTML document (as opposed to attributes.)
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*
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* @param string $string String to have entities parsed.
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* @return string Parsed string.
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*/
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public function substituteTextEntities($string)
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{
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return preg_replace_callback(
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$this->_textEntitiesRegex,
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array($this, 'entityCallback'),
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$string
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);
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}
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/**
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* Substitute entities with the parsed equivalents. Use this on
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* attribute contents in documents.
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*
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* @param string $string String to have entities parsed.
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* @return string Parsed string.
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*/
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public function substituteAttrEntities($string)
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{
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return preg_replace_callback(
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$this->_attrEntitiesRegex,
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array($this, 'entityCallback'),
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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 array $matches PCRE matches array, with 0 the entire match, and
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* either index 1, 2 or 3 set with a hex value, dec value,
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* or string (respectively).
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* @return string Replacement string.
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*/
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protected function entityCallback($matches)
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{
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$entity = $matches[0];
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$hex_part = @$matches[1];
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$dec_part = @$matches[2];
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$named_part = empty($matches[3]) ? (empty($matches[4]) ? "" : $matches[4]) : $matches[3];
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if ($hex_part !== NULL && $hex_part !== "") {
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return HTMLPurifier_Encoder::unichr(hexdec($hex_part));
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} elseif ($dec_part !== NULL && $dec_part !== "") {
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return HTMLPurifier_Encoder::unichr((int) $dec_part);
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} else {
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if (!$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[$named_part])) {
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return $this->_entity_lookup->table[$named_part];
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} else {
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// exact match didn't match anything, so test if
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// any of the semicolon optional match the prefix.
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// Test that this is an EXACT match is important to
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// prevent infinite loop
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if (!empty($matches[3])) {
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return preg_replace_callback(
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$this->_semiOptionalPrefixRegex,
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array($this, 'entityCallback'),
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$entity
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);
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}
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return $entity;
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}
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}
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}
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// LEGACY CODE BELOW
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/**
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* Callback regex string for parsing entities.
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* @type string
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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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* @type array
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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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* @type array
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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 $string String to have non-special entities parsed.
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* @return string Parsed string.
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*/
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public function substituteNonSpecialEntities($string)
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{
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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 array $matches PCRE matches array, with 0 the entire match, and
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* either index 1, 2 or 3 set with a hex value, dec value,
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* or string (respectively).
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* @return string Replacement string.
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*/
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protected function nonSpecialEntityCallback($matches)
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{
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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])) {
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return $entity;
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}
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return HTMLPurifier_Encoder::unichr($code);
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} else {
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if (isset($this->_special_ent2dec[$matches[3]])) {
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return $entity;
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}
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if (!$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 $string String to have non-special entities parsed.
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* @return string Parsed string.
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*/
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public function substituteSpecialEntities($string)
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{
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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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/**
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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 array $matches PCRE-style matches array, with 0 the entire match, and
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* either index 1, 2 or 3 set with a hex value, dec value,
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* or string (respectively).
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* @return string Replacement string.
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*/
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protected function specialEntityCallback($matches)
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{
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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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$this->_special_dec2str[$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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