<?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.
* @type HTMLPurifier_EntityLookup
*/
protected $_entity_lookup;
/**
* Callback regex string for entities in text.
* @type string
*/
protected $_textEntitiesRegex;
/**
* Callback regex string for entities in attributes.
* @type string
*/
protected $_attrEntitiesRegex;
/**
* Tests if the beginning of a string is a semi-optional regex
*/
protected $_semiOptionalPrefixRegex;
public function __construct() {
// From
// http://stackoverflow.com/questions/15532252/why-is-reg-being-rendered-as-without-the-bounding-semicolon
$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";
// NB: three empty captures to put the fourth match in the right
// place
$this->_semiOptionalPrefixRegex = "/&()()()($semi_optional)/";
$this->_textEntitiesRegex =
'/&(?:'.
// hex
'[#]x([a-fA-F0-9]+);?|'.
// dec
'[#]0*(\d+);?|'.
// string (mandatory semicolon)
// NB: order matters: match semicolon preferentially
'([A-Za-z_:][A-Za-z0-9.\-_:]*);|'.
// string (optional semicolon)
"($semi_optional)".
')/';
$this->_attrEntitiesRegex =
'/&(?:'.
// hex
'[#]x([a-fA-F0-9]+);?|'.
// dec
'[#]0*(\d+);?|'.
// string (mandatory semicolon)
// NB: order matters: match semicolon preferentially
'([A-Za-z_:][A-Za-z0-9.\-_:]*);|'.
// string (optional semicolon)
// don't match if trailing is equals or alphanumeric (URL
// like)
"($semi_optional)(?![=;A-Za-z0-9])".
')/';
}
/**
* Substitute entities with the parsed equivalents. Use this on
* textual data in an HTML document (as opposed to attributes.)
*
* @param string $string String to have entities parsed.
* @return string Parsed string.
*/
public function substituteTextEntities($string)
{
return preg_replace_callback(
$this->_textEntitiesRegex,
array($this, 'entityCallback'),
$string
);
}
/**
* Substitute entities with the parsed equivalents. Use this on
* attribute contents in documents.
*
* @param string $string String to have entities parsed.
* @return string Parsed string.
*/
public function substituteAttrEntities($string)
{
return preg_replace_callback(
$this->_attrEntitiesRegex,
array($this, 'entityCallback'),
$string
);
}
/**
* Callback function for substituteNonSpecialEntities() that does the work.
*
* @param array $matches PCRE matches array, with 0 the entire match, and
* either index 1, 2 or 3 set with a hex value, dec value,
* or string (respectively).
* @return string Replacement string.
*/
protected function entityCallback($matches)
{
$entity = $matches[0];
$hex_part = @$matches[1];
$dec_part = @$matches[2];
$named_part = empty($matches[3]) ? (empty($matches[4]) ? "" : $matches[4]) : $matches[3];
if ($hex_part !== NULL && $hex_part !== "") {
return HTMLPurifier_Encoder::unichr(hexdec($hex_part));
} elseif ($dec_part !== NULL && $dec_part !== "") {
return HTMLPurifier_Encoder::unichr((int) $dec_part);
} else {
if (!$this->_entity_lookup) {
$this->_entity_lookup = HTMLPurifier_EntityLookup::instance();
}
if (isset($this->_entity_lookup->table[$named_part])) {
return $this->_entity_lookup->table[$named_part];
} else {
// exact match didn't match anything, so test if
// any of the semicolon optional match the prefix.
// Test that this is an EXACT match is important to
// prevent infinite loop
if (!empty($matches[3])) {
return preg_replace_callback(
$this->_semiOptionalPrefixRegex,
array($this, 'entityCallback'),
$entity
);
}
return $entity;
}
}
}
// LEGACY CODE BELOW
/**
* Callback regex string for parsing entities.
* @type string
*/
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.
* @type array
*/
protected $_special_dec2str =
array(
34 => '"',
38 => '&',
39 => "'",
60 => '<',
62 => '>'
);
/**
* Stripped entity names to decimal conversion table for special entities.
* @type array
*/
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 $string String to have non-special entities parsed.
* @return string Parsed string.
*/
public function substituteNonSpecialEntities($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 array $matches PCRE matches array, with 0 the entire match, and
* either index 1, 2 or 3 set with a hex value, dec value,
* or string (respectively).
* @return string Replacement string.
*/
protected function nonSpecialEntityCallback($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 $string String to have non-special entities parsed.
* @return string Parsed string.
*/
public function substituteSpecialEntities($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 array $matches PCRE-style matches array, with 0 the entire match, and
* either index 1, 2 or 3 set with a hex value, dec value,
* or string (respectively).
* @return string Replacement string.
*/
protected function specialEntityCallback($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]]) ?
$this->_special_dec2str[$this->_special_ent2dec[$matches[3]]] :
$entity;
}
}
}
// vim: et sw=4 sts=4