<?php

/**
 * @file
 * This file was auto-generated by generate-includes.php and includes all of
 * the core files required by HTML Purifier. Use this if performance is a
 * primary concern and you are using an opcode cache. PLEASE DO NOT EDIT THIS
 * FILE, changes will be overwritten the next time the script is run.
 * 
 * @version 3.1.1
 * 
 * @warning
 *      You must *not* include any other HTML Purifier files before this file,
 *      because 'require' not 'require_once' is used.
 * 
 * @warning
 *      This file requires that the include path contains the HTML Purifier
 *      library directory; this is not auto-set.
 */



/*! @mainpage
 * 
 * HTML Purifier is an HTML filter that will take an arbitrary snippet of
 * HTML and rigorously test, validate and filter it into a version that
 * is safe for output onto webpages. It achieves this by:
 * 
 *  -# Lexing (parsing into tokens) the document,
 *  -# Executing various strategies on the tokens:
 *      -# Removing all elements not in the whitelist,
 *      -# Making the tokens well-formed,
 *      -# Fixing the nesting of the nodes, and
 *      -# Validating attributes of the nodes; and
 *  -# Generating HTML from the purified tokens.
 * 
 * However, most users will only need to interface with the HTMLPurifier
 * and HTMLPurifier_Config.
 */

/*
    HTML Purifier 3.1.1 - Standards Compliant HTML Filtering
    Copyright (C) 2006-2008 Edward Z. Yang

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

/**
 * Facade that coordinates HTML Purifier's subsystems in order to purify HTML.
 * 
 * @note There are several points in which configuration can be specified 
 *       for HTML Purifier.  The precedence of these (from lowest to
 *       highest) is as follows:
 *          -# Instance: new HTMLPurifier($config)
 *          -# Invocation: purify($html, $config)
 *       These configurations are entirely independent of each other and
 *       are *not* merged (this behavior may change in the future).
 * 
 * @todo We need an easier way to inject strategies using the configuration
 *       object.
 */
class HTMLPurifier
{
    
    /** Version of HTML Purifier */
    public $version = '3.1.1';
    
    /** Constant with version of HTML Purifier */
    const VERSION = '3.1.1';
    
    /** Global configuration object */
    public $config;
    
    /** Array of extra HTMLPurifier_Filter objects to run on HTML, for backwards compatibility */
    private $filters = array();
    
    /** Single instance of HTML Purifier */
    private static $instance;
    
    protected $strategy, $generator;
    
    /**
     * Resultant HTMLPurifier_Context of last run purification. Is an array
     * of contexts if the last called method was purifyArray().
     */
    public $context;
    
    /**
     * Initializes the purifier.
     * @param $config Optional HTMLPurifier_Config object for all instances of
     *                the purifier, if omitted, a default configuration is
     *                supplied (which can be overridden on a per-use basis).
     *                The parameter can also be any type that
     *                HTMLPurifier_Config::create() supports.
     */
    public function __construct($config = null) {
        
        $this->config = HTMLPurifier_Config::create($config);
        
        $this->strategy     = new HTMLPurifier_Strategy_Core();
        
    }
    
    /**
     * Adds a filter to process the output. First come first serve
     * @param $filter HTMLPurifier_Filter object
     */
    public function addFilter($filter) {
        trigger_error('HTMLPurifier->addFilter() is deprecated, use configuration directives in the Filter namespace or Filter.Custom', E_USER_WARNING);
        $this->filters[] = $filter;
    }
    
    /**
     * Filters an HTML snippet/document to be XSS-free and standards-compliant.
     * 
     * @param $html String of HTML to purify
     * @param $config HTMLPurifier_Config object for this operation, if omitted,
     *                defaults to the config object specified during this
     *                object's construction. The parameter can also be any type
     *                that HTMLPurifier_Config::create() supports.
     * @return Purified HTML
     */
    public function purify($html, $config = null) {
        
        // :TODO: make the config merge in, instead of replace
        $config = $config ? HTMLPurifier_Config::create($config) : $this->config;
        
        // implementation is partially environment dependant, partially
        // configuration dependant
        $lexer = HTMLPurifier_Lexer::create($config);
        
        $context = new HTMLPurifier_Context();
        
        // setup HTML generator
        $this->generator = new HTMLPurifier_Generator($config, $context);
        $context->register('Generator', $this->generator);
        
        // set up global context variables
        if ($config->get('Core', 'CollectErrors')) {
            // may get moved out if other facilities use it
            $language_factory = HTMLPurifier_LanguageFactory::instance();
            $language = $language_factory->create($config, $context);
            $context->register('Locale', $language);
            
            $error_collector = new HTMLPurifier_ErrorCollector($context);
            $context->register('ErrorCollector', $error_collector);
        }
        
        // setup id_accumulator context, necessary due to the fact that
        // AttrValidator can be called from many places
        $id_accumulator = HTMLPurifier_IDAccumulator::build($config, $context);
        $context->register('IDAccumulator', $id_accumulator);
        
        $html = HTMLPurifier_Encoder::convertToUTF8($html, $config, $context);
        
        // setup filters
        $filter_flags = $config->getBatch('Filter');
        $custom_filters = $filter_flags['Custom'];
        unset($filter_flags['Custom']);
        $filters = array();
        foreach ($filter_flags as $filter => $flag) {
            if (!$flag) continue;
            $class = "HTMLPurifier_Filter_$filter";
            $filters[] = new $class;
        }
        foreach ($custom_filters as $filter) {
            // maybe "HTMLPurifier_Filter_$filter", but be consistent with AutoFormat
            $filters[] = $filter;
        }
        $filters = array_merge($filters, $this->filters);
        // maybe prepare(), but later
        
        for ($i = 0, $filter_size = count($filters); $i < $filter_size; $i++) {
            $html = $filters[$i]->preFilter($html, $config, $context);
        }
        
        // purified HTML
        $html = 
            $this->generator->generateFromTokens(
                // list of tokens
                $this->strategy->execute(
                    // list of un-purified tokens
                    $lexer->tokenizeHTML(
                        // un-purified HTML
                        $html, $config, $context
                    ),
                    $config, $context
                )
            );
        
        for ($i = $filter_size - 1; $i >= 0; $i--) {
            $html = $filters[$i]->postFilter($html, $config, $context);
        }
        
        $html = HTMLPurifier_Encoder::convertFromUTF8($html, $config, $context);
        $this->context =& $context;
        return $html;
    }
    
    /**
     * Filters an array of HTML snippets
     * @param $config Optional HTMLPurifier_Config object for this operation.
     *                See HTMLPurifier::purify() for more details.
     * @return Array of purified HTML
     */
    public function purifyArray($array_of_html, $config = null) {
        $context_array = array();
        foreach ($array_of_html as $key => $html) {
            $array_of_html[$key] = $this->purify($html, $config);
            $context_array[$key] = $this->context;
        }
        $this->context = $context_array;
        return $array_of_html;
    }
    
    /**
     * Singleton for enforcing just one HTML Purifier in your system
     * @param $prototype Optional prototype HTMLPurifier instance to
     *                   overload singleton with, or HTMLPurifier_Config
     *                   instance to configure the generated version with.
     */
    public static function instance($prototype = null) {
        if (!self::$instance || $prototype) {
            if ($prototype instanceof HTMLPurifier) {
                self::$instance = $prototype;
            } elseif ($prototype) {
                self::$instance = new HTMLPurifier($prototype);
            } else {
                self::$instance = new HTMLPurifier();
            }
        }
        return self::$instance;
    }
    
    /**
     * @note Backwards compatibility, see instance()
     */
    public static function getInstance($prototype = null) {
        return HTMLPurifier::instance($prototype);
    }
    
}



/**
 * Defines common attribute collections that modules reference
 */

class HTMLPurifier_AttrCollections
{
    
    /**
     * Associative array of attribute collections, indexed by name
     */
    public $info = array();
    
    /**
     * Performs all expansions on internal data for use by other inclusions
     * It also collects all attribute collection extensions from
     * modules
     * @param $attr_types HTMLPurifier_AttrTypes instance
     * @param $modules Hash array of HTMLPurifier_HTMLModule members
     */
    public function __construct($attr_types, $modules) {
        // load extensions from the modules
        foreach ($modules as $module) {
            foreach ($module->attr_collections as $coll_i => $coll) {
                if (!isset($this->info[$coll_i])) {
                    $this->info[$coll_i] = array();
                }
                foreach ($coll as $attr_i => $attr) {
                    if ($attr_i === 0 && isset($this->info[$coll_i][$attr_i])) {
                        // merge in includes
                        $this->info[$coll_i][$attr_i] = array_merge(
                            $this->info[$coll_i][$attr_i], $attr);
                        continue;
                    }
                    $this->info[$coll_i][$attr_i] = $attr;
                }
            }
        }
        // perform internal expansions and inclusions
        foreach ($this->info as $name => $attr) {
            // merge attribute collections that include others
            $this->performInclusions($this->info[$name]);
            // replace string identifiers with actual attribute objects
            $this->expandIdentifiers($this->info[$name], $attr_types);
        }
    }
    
    /**
     * Takes a reference to an attribute associative array and performs
     * all inclusions specified by the zero index.
     * @param &$attr Reference to attribute array
     */
    public function performInclusions(&$attr) {
        if (!isset($attr[0])) return;
        $merge = $attr[0];
        $seen  = array(); // recursion guard
        // loop through all the inclusions
        for ($i = 0; isset($merge[$i]); $i++) {
            if (isset($seen[$merge[$i]])) continue;
            $seen[$merge[$i]] = true;
            // foreach attribute of the inclusion, copy it over
            if (!isset($this->info[$merge[$i]])) continue;
            foreach ($this->info[$merge[$i]] as $key => $value) {
                if (isset($attr[$key])) continue; // also catches more inclusions
                $attr[$key] = $value;
            }
            if (isset($this->info[$merge[$i]][0])) {
                // recursion
                $merge = array_merge($merge, $this->info[$merge[$i]][0]);
            }
        }
        unset($attr[0]);
    }
    
    /**
     * Expands all string identifiers in an attribute array by replacing
     * them with the appropriate values inside HTMLPurifier_AttrTypes
     * @param &$attr Reference to attribute array
     * @param $attr_types HTMLPurifier_AttrTypes instance
     */
    public function expandIdentifiers(&$attr, $attr_types) {
        
        // because foreach will process new elements we add, make sure we
        // skip duplicates
        $processed = array();
        
        foreach ($attr as $def_i => $def) {
            // skip inclusions
            if ($def_i === 0) continue;
            
            if (isset($processed[$def_i])) continue;
            
            // determine whether or not attribute is required
            if ($required = (strpos($def_i, '*') !== false)) {
                // rename the definition
                unset($attr[$def_i]);
                $def_i = trim($def_i, '*');
                $attr[$def_i] = $def;
            }
            
            $processed[$def_i] = true;
            
            // if we've already got a literal object, move on
            if (is_object($def)) {
                // preserve previous required
                $attr[$def_i]->required = ($required || $attr[$def_i]->required);
                continue;
            }
            
            if ($def === false) {
                unset($attr[$def_i]);
                continue;
            }
            
            if ($t = $attr_types->get($def)) {
                $attr[$def_i] = $t;
                $attr[$def_i]->required = $required;
            } else {
                unset($attr[$def_i]);
            }
        }
        
    }
    
}




/**
 * Base class for all validating attribute definitions.
 * 
 * This family of classes forms the core for not only HTML attribute validation,
 * but also any sort of string that needs to be validated or cleaned (which
 * means CSS properties and composite definitions are defined here too).  
 * Besides defining (through code) what precisely makes the string valid,
 * subclasses are also responsible for cleaning the code if possible.
 */

abstract class HTMLPurifier_AttrDef
{
    
    /**
     * Tells us whether or not an HTML attribute is minimized. Has no
     * meaning in other contexts.
     */
    public $minimized = false;
    
    /**
     * Tells us whether or not an HTML attribute is required. Has no
     * meaning in other contexts
     */
    public $required = false;
    
    /**
     * Validates and cleans passed string according to a definition.
     * 
     * @param $string String to be validated and cleaned.
     * @param $config Mandatory HTMLPurifier_Config object.
     * @param $context Mandatory HTMLPurifier_AttrContext object.
     */
    abstract public function validate($string, $config, $context);
    
    /**
     * Convenience method that parses a string as if it were CDATA.
     * 
     * This method process a string in the manner specified at
     * <http://www.w3.org/TR/html4/types.html#h-6.2> by removing
     * leading and trailing whitespace, ignoring line feeds, and replacing
     * carriage returns and tabs with spaces.  While most useful for HTML
     * attributes specified as CDATA, it can also be applied to most CSS
     * values.
     * 
     * @note This method is not entirely standards compliant, as trim() removes
     *       more types of whitespace than specified in the spec. In practice,
     *       this is rarely a problem, as those extra characters usually have
     *       already been removed by HTMLPurifier_Encoder.
     * 
     * @warning This processing is inconsistent with XML's whitespace handling
     *          as specified by section 3.3.3 and referenced XHTML 1.0 section
     *          4.7.  However, note that we are NOT necessarily
     *          parsing XML, thus, this behavior may still be correct. We
     *          assume that newlines have been normalized.
     */
    public function parseCDATA($string) {
        $string = trim($string);
        $string = str_replace(array("\n", "\t", "\r"), ' ', $string);
        return $string;
    }
    
    /**
     * Factory method for creating this class from a string.
     * @param $string String construction info
     * @return Created AttrDef object corresponding to $string
     */
    public function make($string) {
        // default implementation, return a flyweight of this object.
        // If $string has an effect on the returned object (i.e. you
        // need to overload this method), it is best
        // to clone or instantiate new copies. (Instantiation is safer.)
        return $this;
    }
    
    /**
     * Removes spaces from rgb(0, 0, 0) so that shorthand CSS properties work
     * properly. THIS IS A HACK!
     */
    protected function mungeRgb($string) {
        return preg_replace('/rgb\((\d+)\s*,\s*(\d+)\s*,\s*(\d+)\)/', 'rgb(\1,\2,\3)', $string);
    }
    
}




/**
 * Processes an entire attribute array for corrections needing multiple values.
 * 
 * Occasionally, a certain attribute will need to be removed and popped onto
 * another value.  Instead of creating a complex return syntax for
 * HTMLPurifier_AttrDef, we just pass the whole attribute array to a
 * specialized object and have that do the special work.  That is the
 * family of HTMLPurifier_AttrTransform.
 * 
 * An attribute transformation can be assigned to run before or after
 * HTMLPurifier_AttrDef validation.  See HTMLPurifier_HTMLDefinition for
 * more details.
 */

abstract class HTMLPurifier_AttrTransform
{
    
    /**
     * Abstract: makes changes to the attributes dependent on multiple values.
     * 
     * @param $attr Assoc array of attributes, usually from
     *              HTMLPurifier_Token_Tag::$attr
     * @param $config Mandatory HTMLPurifier_Config object.
     * @param $context Mandatory HTMLPurifier_Context object
     * @returns Processed attribute array.
     */
    abstract public function transform($attr, $config, $context);
    
    /**
     * Prepends CSS properties to the style attribute, creating the
     * attribute if it doesn't exist.
     * @param $attr Attribute array to process (passed by reference)
     * @param $css CSS to prepend
     */
    public function prependCSS(&$attr, $css) {
        $attr['style'] = isset($attr['style']) ? $attr['style'] : '';
        $attr['style'] = $css . $attr['style'];
    }
    
    /**
     * Retrieves and removes an attribute
     * @param $attr Attribute array to process (passed by reference)
     * @param $key Key of attribute to confiscate
     */
    public function confiscateAttr(&$attr, $key) {
        if (!isset($attr[$key])) return null;
        $value = $attr[$key];
        unset($attr[$key]);
        return $value;
    }
    
}




/**
 * Provides lookup array of attribute types to HTMLPurifier_AttrDef objects
 */
class HTMLPurifier_AttrTypes
{
    /**
     * Lookup array of attribute string identifiers to concrete implementations
     */
    protected $info = array();
    
    /**
     * Constructs the info array, supplying default implementations for attribute
     * types.
     */
    public function __construct() {
        // pseudo-types, must be instantiated via shorthand
        $this->info['Enum']    = new HTMLPurifier_AttrDef_Enum();
        $this->info['Bool']    = new HTMLPurifier_AttrDef_HTML_Bool();
        
        $this->info['CDATA']    = new HTMLPurifier_AttrDef_Text();
        $this->info['ID']       = new HTMLPurifier_AttrDef_HTML_ID();
        $this->info['Length']   = new HTMLPurifier_AttrDef_HTML_Length();
        $this->info['MultiLength'] = new HTMLPurifier_AttrDef_HTML_MultiLength();
        $this->info['NMTOKENS'] = new HTMLPurifier_AttrDef_HTML_Nmtokens();
        $this->info['Pixels']   = new HTMLPurifier_AttrDef_HTML_Pixels();
        $this->info['Text']     = new HTMLPurifier_AttrDef_Text();
        $this->info['URI']      = new HTMLPurifier_AttrDef_URI();
        $this->info['LanguageCode'] = new HTMLPurifier_AttrDef_Lang();
        $this->info['Color']    = new HTMLPurifier_AttrDef_HTML_Color();
        
        // unimplemented aliases
        $this->info['ContentType'] = new HTMLPurifier_AttrDef_Text();
        
        // number is really a positive integer (one or more digits)
        // FIXME: ^^ not always, see start and value of list items
        $this->info['Number']   = new HTMLPurifier_AttrDef_Integer(false, false, true);
    }
    
    /**
     * Retrieves a type
     * @param $type String type name
     * @return Object AttrDef for type
     */
    public function get($type) {
        
        // determine if there is any extra info tacked on
        if (strpos($type, '#') !== false) list($type, $string) = explode('#', $type, 2);
        else $string = '';
        
        if (!isset($this->info[$type])) {
            trigger_error('Cannot retrieve undefined attribute type ' . $type, E_USER_ERROR);
            return;
        }
        
        return $this->info[$type]->make($string);
        
    }
    
    /**
     * Sets a new implementation for a type
     * @param $type String type name
     * @param $impl Object AttrDef for type
     */
    public function set($type, $impl) {
        $this->info[$type] = $impl;
    }
}





/**
 * Validates the attributes of a token. Doesn't manage required attributes
 * very well. The only reason we factored this out was because RemoveForeignElements
 * also needed it besides ValidateAttributes.
 */
class HTMLPurifier_AttrValidator
{
    
    /**
     * Validates the attributes of a token, returning a modified token
     * that has valid tokens
     * @param $token Reference to token to validate. We require a reference
     *     because the operation this class performs on the token are
     *     not atomic, so the context CurrentToken to be updated
     *     throughout
     * @param $config Instance of HTMLPurifier_Config
     * @param $context Instance of HTMLPurifier_Context
     */
    public function validateToken(&$token, &$config, $context) {
            
        $definition = $config->getHTMLDefinition();
        $e =& $context->get('ErrorCollector', true);
        
        // initialize IDAccumulator if necessary
        $ok =& $context->get('IDAccumulator', true);
        if (!$ok) {
            $id_accumulator = HTMLPurifier_IDAccumulator::build($config, $context);
            $context->register('IDAccumulator', $id_accumulator);
        }
        
        // initialize CurrentToken if necessary
        $current_token =& $context->get('CurrentToken', true);
        if (!$current_token) $context->register('CurrentToken', $token);
        
        if (
          !$token instanceof HTMLPurifier_Token_Start &&
          !$token instanceof HTMLPurifier_Token_Empty
        ) return $token;
        
        // create alias to global definition array, see also $defs
        // DEFINITION CALL
        $d_defs = $definition->info_global_attr;
        
        // don't update token until the very end, to ensure an atomic update
        $attr = $token->attr;
        
        // do global transformations (pre)
        // nothing currently utilizes this
        foreach ($definition->info_attr_transform_pre as $transform) {
            $attr = $transform->transform($o = $attr, $config, $context);
            if ($e && ($attr != $o)) $e->send(E_NOTICE, 'AttrValidator: Attributes transformed', $o, $attr);
        }
        
        // do local transformations only applicable to this element (pre)
        // ex. <p align="right"> to <p style="text-align:right;">
        foreach ($definition->info[$token->name]->attr_transform_pre as $transform) {
            $attr = $transform->transform($o = $attr, $config, $context);
            if ($e && ($attr != $o)) $e->send(E_NOTICE, 'AttrValidator: Attributes transformed', $o, $attr);
        }
        
        // create alias to this element's attribute definition array, see
        // also $d_defs (global attribute definition array)
        // DEFINITION CALL
        $defs = $definition->info[$token->name]->attr;
        
        $attr_key = false;
        $context->register('CurrentAttr', $attr_key);
        
        // iterate through all the attribute keypairs
        // Watch out for name collisions: $key has previously been used
        foreach ($attr as $attr_key => $value) {
            
            // call the definition
            if ( isset($defs[$attr_key]) ) {
                // there is a local definition defined
                if ($defs[$attr_key] === false) {
                    // We've explicitly been told not to allow this element.
                    // This is usually when there's a global definition
                    // that must be overridden.
                    // Theoretically speaking, we could have a
                    // AttrDef_DenyAll, but this is faster!
                    $result = false;
                } else {
                    // validate according to the element's definition
                    $result = $defs[$attr_key]->validate(
                                    $value, $config, $context
                               );
                }
            } elseif ( isset($d_defs[$attr_key]) ) {
                // there is a global definition defined, validate according
                // to the global definition
                $result = $d_defs[$attr_key]->validate(
                                $value, $config, $context
                           );
            } else {
                // system never heard of the attribute? DELETE!
                $result = false;
            }
            
            // put the results into effect
            if ($result === false || $result === null) {
                // this is a generic error message that should replaced
                // with more specific ones when possible
                if ($e) $e->send(E_ERROR, 'AttrValidator: Attribute removed');
                
                // remove the attribute
                unset($attr[$attr_key]);
            } elseif (is_string($result)) {
                // generally, if a substitution is happening, there
                // was some sort of implicit correction going on. We'll
                // delegate it to the attribute classes to say exactly what.
                
                // simple substitution
                $attr[$attr_key] = $result;
            }
            
            // we'd also want slightly more complicated substitution
            // involving an array as the return value,
            // although we're not sure how colliding attributes would
            // resolve (certain ones would be completely overriden,
            // others would prepend themselves).
        }
        
        $context->destroy('CurrentAttr');
        
        // post transforms
        
        // global (error reporting untested)
        foreach ($definition->info_attr_transform_post as $transform) {
            $attr = $transform->transform($o = $attr, $config, $context);
            if ($e && ($attr != $o)) $e->send(E_NOTICE, 'AttrValidator: Attributes transformed', $o, $attr);
        }
        
        // local (error reporting untested)
        foreach ($definition->info[$token->name]->attr_transform_post as $transform) {
            $attr = $transform->transform($o = $attr, $config, $context);
            if ($e && ($attr != $o)) $e->send(E_NOTICE, 'AttrValidator: Attributes transformed', $o, $attr);
        }
        
        $token->attr = $attr;
        
        // destroy CurrentToken if we made it ourselves
        if (!$current_token) $context->destroy('CurrentToken');
        
    }
    
    
}




// constants are slow, so we use as few as possible
if (!defined('HTMLPURIFIER_PREFIX')) {
    define('HTMLPURIFIER_PREFIX', dirname(__FILE__) . '/standalone');
    set_include_path(HTMLPURIFIER_PREFIX . PATH_SEPARATOR . get_include_path());
}

// accomodations for versions earlier than 5.0.2
// borrowed from PHP_Compat, LGPL licensed, by Aidan Lister <aidan@php.net>
if (!defined('PHP_EOL')) {
    switch (strtoupper(substr(PHP_OS, 0, 3))) {
        case 'WIN':
            define('PHP_EOL', "\r\n");
            break;
        case 'DAR':
            define('PHP_EOL', "\r");
            break;
        default:
            define('PHP_EOL', "\n");
    }
}

/**
 * Bootstrap class that contains meta-functionality for HTML Purifier such as
 * the autoload function.
 *
 * @note
 *      This class may be used without any other files from HTML Purifier.
 */
class HTMLPurifier_Bootstrap
{
    
    /**
     * Autoload function for HTML Purifier
     * @param $class Class to load
     */
    public static function autoload($class) {
        $file = HTMLPurifier_Bootstrap::getPath($class);
        if (!$file) return false;
        require HTMLPURIFIER_PREFIX . '/' . $file;
        return true;
    }
    
    /**
     * Returns the path for a specific class.
     */
    public static function getPath($class) {
        if (strncmp('HTMLPurifier', $class, 12) !== 0) return false;
        // Custom implementations
        if (strncmp('HTMLPurifier_Language_', $class, 22) === 0) {
            $code = str_replace('_', '-', substr($class, 22));
            $file = 'HTMLPurifier/Language/classes/' . $code . '.php';
        } else {
            $file = str_replace('_', '/', $class) . '.php';
        }
        if (!file_exists(HTMLPURIFIER_PREFIX . '/' . $file)) return false;
        return $file;
    }
    
    /**
     * "Pre-registers" our autoloader on the SPL stack.
     */
    public static function registerAutoload() {
        $autoload = array('HTMLPurifier_Bootstrap', 'autoload');
        if ( ($funcs = spl_autoload_functions()) === false ) {
            spl_autoload_register($autoload);
        } elseif (function_exists('spl_autoload_unregister')) {
            $compat = version_compare(PHP_VERSION, '5.1.2', '<=') &&
                      version_compare(PHP_VERSION, '5.1.0', '>=');
            foreach ($funcs as $func) {
                if (is_array($func)) {
                    // :TRICKY: There are some compatibility issues and some
                    // places where we need to error out
                    $reflector = new ReflectionMethod($func[0], $func[1]);
                    if (!$reflector->isStatic()) {
                        throw new Exception('
                            HTML Purifier autoloader registrar is not compatible
                            with non-static object methods due to PHP Bug #44144;
                            Please do not use HTMLPurifier.autoload.php (or any
                            file that includes this file); instead, place the code:
                            spl_autoload_register(array(\'HTMLPurifier_Bootstrap\', \'autoload\'))
                            after your own autoloaders.
                        ');
                    }
                    // Suprisingly, spl_autoload_register supports the
                    // Class::staticMethod callback format, although call_user_func doesn't
                    if ($compat) $func = implode('::', $func);
                }
                spl_autoload_unregister($func);
            }
            spl_autoload_register($autoload);
            foreach ($funcs as $func) spl_autoload_register($func);
        }
    }
    
}



/**
 * Super-class for definition datatype objects, implements serialization
 * functions for the class.
 */
abstract class HTMLPurifier_Definition
{
    
    /**
     * Has setup() been called yet?
     */
    public $setup = false;
    
    /**
     * What type of definition is it?
     */
    public $type;
    
    /**
     * Sets up the definition object into the final form, something
     * not done by the constructor
     * @param $config HTMLPurifier_Config instance
     */
    abstract protected function doSetup($config);
    
    /**
     * Setup function that aborts if already setup
     * @param $config HTMLPurifier_Config instance
     */
    public function setup($config) {
        if ($this->setup) return;
        $this->setup = true;
        $this->doSetup($config);
    }
    
}




/**
 * Defines allowed CSS attributes and what their values are.
 * @see HTMLPurifier_HTMLDefinition
 */
class HTMLPurifier_CSSDefinition extends HTMLPurifier_Definition
{
    
    public $type = 'CSS';
    
    /**
     * Assoc array of attribute name to definition object.
     */
    public $info = array();
    
    /**
     * Constructs the info array.  The meat of this class.
     */
    protected function doSetup($config) {
        
        $this->info['text-align'] = new HTMLPurifier_AttrDef_Enum(
            array('left', 'right', 'center', 'justify'), false);
        
        $border_style =
        $this->info['border-bottom-style'] = 
        $this->info['border-right-style'] = 
        $this->info['border-left-style'] = 
        $this->info['border-top-style'] =  new HTMLPurifier_AttrDef_Enum(
            array('none', 'hidden', 'dotted', 'dashed', 'solid', 'double',
            'groove', 'ridge', 'inset', 'outset'), false);
        
        $this->info['border-style'] = new HTMLPurifier_AttrDef_CSS_Multiple($border_style);
        
        $this->info['clear'] = new HTMLPurifier_AttrDef_Enum(
            array('none', 'left', 'right', 'both'), false);
        $this->info['float'] = new HTMLPurifier_AttrDef_Enum(
            array('none', 'left', 'right'), false);
        $this->info['font-style'] = new HTMLPurifier_AttrDef_Enum(
            array('normal', 'italic', 'oblique'), false);
        $this->info['font-variant'] = new HTMLPurifier_AttrDef_Enum(
            array('normal', 'small-caps'), false);
        
        $uri_or_none = new HTMLPurifier_AttrDef_CSS_Composite(
            array(
                new HTMLPurifier_AttrDef_Enum(array('none')),
                new HTMLPurifier_AttrDef_CSS_URI()
            )
        );
        
        $this->info['list-style-position'] = new HTMLPurifier_AttrDef_Enum(
            array('inside', 'outside'), false);
        $this->info['list-style-type'] = new HTMLPurifier_AttrDef_Enum(
            array('disc', 'circle', 'square', 'decimal', 'lower-roman',
            'upper-roman', 'lower-alpha', 'upper-alpha', 'none'), false);
        $this->info['list-style-image'] = $uri_or_none;
        
        $this->info['list-style'] = new HTMLPurifier_AttrDef_CSS_ListStyle($config);
        
        $this->info['text-transform'] = new HTMLPurifier_AttrDef_Enum(
            array('capitalize', 'uppercase', 'lowercase', 'none'), false);
        $this->info['color'] = new HTMLPurifier_AttrDef_CSS_Color();
        
        $this->info['background-image'] = $uri_or_none;
        $this->info['background-repeat'] = new HTMLPurifier_AttrDef_Enum(
            array('repeat', 'repeat-x', 'repeat-y', 'no-repeat')
        );
        $this->info['background-attachment'] = new HTMLPurifier_AttrDef_Enum(
            array('scroll', 'fixed')
        );
        $this->info['background-position'] = new HTMLPurifier_AttrDef_CSS_BackgroundPosition();
        
        $border_color = 
        $this->info['border-top-color'] = 
        $this->info['border-bottom-color'] = 
        $this->info['border-left-color'] = 
        $this->info['border-right-color'] = 
        $this->info['background-color'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_Enum(array('transparent')),
            new HTMLPurifier_AttrDef_CSS_Color()
        ));
        
        $this->info['background'] = new HTMLPurifier_AttrDef_CSS_Background($config);
        
        $this->info['border-color'] = new HTMLPurifier_AttrDef_CSS_Multiple($border_color);
        
        $border_width = 
        $this->info['border-top-width'] = 
        $this->info['border-bottom-width'] = 
        $this->info['border-left-width'] = 
        $this->info['border-right-width'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_Enum(array('thin', 'medium', 'thick')),
            new HTMLPurifier_AttrDef_CSS_Length('0') //disallow negative
        ));
        
        $this->info['border-width'] = new HTMLPurifier_AttrDef_CSS_Multiple($border_width);
        
        $this->info['letter-spacing'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_Enum(array('normal')),
            new HTMLPurifier_AttrDef_CSS_Length()
        ));
        
        $this->info['word-spacing'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_Enum(array('normal')),
            new HTMLPurifier_AttrDef_CSS_Length()
        ));
        
        $this->info['font-size'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_Enum(array('xx-small', 'x-small',
                'small', 'medium', 'large', 'x-large', 'xx-large',
                'larger', 'smaller')),
            new HTMLPurifier_AttrDef_CSS_Percentage(),
            new HTMLPurifier_AttrDef_CSS_Length()
        ));
        
        $this->info['line-height'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_Enum(array('normal')),
            new HTMLPurifier_AttrDef_CSS_Number(true), // no negatives
            new HTMLPurifier_AttrDef_CSS_Length('0'),
            new HTMLPurifier_AttrDef_CSS_Percentage(true)
        ));
        
        $margin =
        $this->info['margin-top'] = 
        $this->info['margin-bottom'] = 
        $this->info['margin-left'] = 
        $this->info['margin-right'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_CSS_Length(),
            new HTMLPurifier_AttrDef_CSS_Percentage(),
            new HTMLPurifier_AttrDef_Enum(array('auto'))
        ));
        
        $this->info['margin'] = new HTMLPurifier_AttrDef_CSS_Multiple($margin);
        
        // non-negative
        $padding =
        $this->info['padding-top'] = 
        $this->info['padding-bottom'] = 
        $this->info['padding-left'] = 
        $this->info['padding-right'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_CSS_Length('0'),
            new HTMLPurifier_AttrDef_CSS_Percentage(true)
        ));
        
        $this->info['padding'] = new HTMLPurifier_AttrDef_CSS_Multiple($padding);
        
        $this->info['text-indent'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_CSS_Length(),
            new HTMLPurifier_AttrDef_CSS_Percentage()
        ));
        
        $trusted_wh = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_CSS_Length('0'),
            new HTMLPurifier_AttrDef_CSS_Percentage(true),
            new HTMLPurifier_AttrDef_Enum(array('auto'))
        ));
        $max = $config->get('CSS', 'MaxImgLength');
        
        $this->info['width'] =
        $this->info['height'] =
            $max === null ?
            $trusted_wh : 
            new HTMLPurifier_AttrDef_Switch('img',
                // For img tags:
                new HTMLPurifier_AttrDef_CSS_Composite(array(
                    new HTMLPurifier_AttrDef_CSS_Length('0', $max),
                    new HTMLPurifier_AttrDef_Enum(array('auto'))
                )),
                // For everyone else:
                $trusted_wh
            );
        
        $this->info['text-decoration'] = new HTMLPurifier_AttrDef_CSS_TextDecoration();
        
        $this->info['font-family'] = new HTMLPurifier_AttrDef_CSS_FontFamily();
        
        // this could use specialized code
        $this->info['font-weight'] = new HTMLPurifier_AttrDef_Enum(
            array('normal', 'bold', 'bolder', 'lighter', '100', '200', '300',
            '400', '500', '600', '700', '800', '900'), false);
        
        // MUST be called after other font properties, as it references
        // a CSSDefinition object
        $this->info['font'] = new HTMLPurifier_AttrDef_CSS_Font($config);
        
        // same here
        $this->info['border'] =
        $this->info['border-bottom'] = 
        $this->info['border-top'] = 
        $this->info['border-left'] = 
        $this->info['border-right'] = new HTMLPurifier_AttrDef_CSS_Border($config);
        
        $this->info['border-collapse'] = new HTMLPurifier_AttrDef_Enum(array(
            'collapse', 'separate'));
        
        $this->info['caption-side'] = new HTMLPurifier_AttrDef_Enum(array(
            'top', 'bottom'));
        
        $this->info['table-layout'] = new HTMLPurifier_AttrDef_Enum(array(
            'auto', 'fixed'));
        
        $this->info['vertical-align'] = new HTMLPurifier_AttrDef_CSS_Composite(array(
            new HTMLPurifier_AttrDef_Enum(array('baseline', 'sub', 'super',
                'top', 'text-top', 'middle', 'bottom', 'text-bottom')),
            new HTMLPurifier_AttrDef_CSS_Length(),
            new HTMLPurifier_AttrDef_CSS_Percentage()
        ));
        
        $this->info['border-spacing'] = new HTMLPurifier_AttrDef_CSS_Multiple(new HTMLPurifier_AttrDef_CSS_Length(), 2);
        
        // partial support
        $this->info['white-space'] = new HTMLPurifier_AttrDef_Enum(array('nowrap'));
        
        if ($config->get('CSS', 'Proprietary')) {
            $this->doSetupProprietary($config);
        }
        
        if ($config->get('CSS', 'AllowTricky')) {
            $this->doSetupTricky($config);
        }
        
        $allow_important = $config->get('CSS', 'AllowImportant');
        // wrap all attr-defs with decorator that handles !important
        foreach ($this->info as $k => $v) {
            $this->info[$k] = new HTMLPurifier_AttrDef_CSS_ImportantDecorator($v, $allow_important);
        }
        
        $this->setupConfigStuff($config);
    }
    
    protected function doSetupProprietary($config) {
        // Internet Explorer only scrollbar colors
        $this->info['scrollbar-arrow-color']        = new HTMLPurifier_AttrDef_CSS_Color();
        $this->info['scrollbar-base-color']         = new HTMLPurifier_AttrDef_CSS_Color();
        $this->info['scrollbar-darkshadow-color']   = new HTMLPurifier_AttrDef_CSS_Color();
        $this->info['scrollbar-face-color']         = new HTMLPurifier_AttrDef_CSS_Color();
        $this->info['scrollbar-highlight-color']    = new HTMLPurifier_AttrDef_CSS_Color();
        $this->info['scrollbar-shadow-color']       = new HTMLPurifier_AttrDef_CSS_Color();
        
        // technically not proprietary, but CSS3, and no one supports it
        $this->info['opacity']          = new HTMLPurifier_AttrDef_CSS_AlphaValue();
        $this->info['-moz-opacity']     = new HTMLPurifier_AttrDef_CSS_AlphaValue();
        $this->info['-khtml-opacity']   = new HTMLPurifier_AttrDef_CSS_AlphaValue();
        
        // only opacity, for now
        $this->info['filter'] = new HTMLPurifier_AttrDef_CSS_Filter();
        
    }
    
    protected function doSetupTricky($config) {
        $this->info['display'] = new HTMLPurifier_AttrDef_Enum(array(
            'inline', 'block', 'list-item', 'run-in', 'compact',
            'marker', 'table', 'inline-table', 'table-row-group',
            'table-header-group', 'table-footer-group', 'table-row',
            'table-column-group', 'table-column', 'table-cell', 'table-caption', 'none'
        ));
        $this->info['visibility'] = new HTMLPurifier_AttrDef_Enum(array(
            'visible', 'hidden', 'collapse'
        ));
    }
    
    
    /**
     * Performs extra config-based processing. Based off of
     * HTMLPurifier_HTMLDefinition.
     * @todo Refactor duplicate elements into common class (probably using
     *       composition, not inheritance).
     */
    protected function setupConfigStuff($config) {
        
        // setup allowed elements
        $support = "(for information on implementing this, see the ".
                   "support forums) ";
        $allowed_attributes = $config->get('CSS', 'AllowedProperties');
        if ($allowed_attributes !== null) {
            foreach ($this->info as $name => $d) {
                if(!isset($allowed_attributes[$name])) unset($this->info[$name]);
                unset($allowed_attributes[$name]);
            }
            // emit errors
            foreach ($allowed_attributes as $name => $d) {
                // :TODO: Is this htmlspecialchars() call really necessary?
                $name = htmlspecialchars($name);
                trigger_error("Style attribute '$name' is not supported $support", E_USER_WARNING);
            }
        }
        
    }
}




/**
 * Defines allowed child nodes and validates tokens against it.
 */
abstract class HTMLPurifier_ChildDef
{
    /**
     * Type of child definition, usually right-most part of class name lowercase.
     * Used occasionally in terms of context.
     */
    public $type;
    
    /**
     * Bool that indicates whether or not an empty array of children is okay
     * 
     * This is necessary for redundant checking when changes affecting
     * a child node may cause a parent node to now be disallowed.
     */
    public $allow_empty;
    
    /**
     * Lookup array of all elements that this definition could possibly allow
     */
    public $elements = array();
    
    /**
     * Validates nodes according to definition and returns modification.
     * 
     * @param $tokens_of_children Array of HTMLPurifier_Token
     * @param $config HTMLPurifier_Config object
     * @param $context HTMLPurifier_Context object
     * @return bool true to leave nodes as is
     * @return bool false to remove parent node
     * @return array of replacement child tokens
     */
    abstract public function validateChildren($tokens_of_children, $config, $context);
}





/**
 * Configuration object that triggers customizable behavior.
 *
 * @warning This class is strongly defined: that means that the class
 *          will fail if an undefined directive is retrieved or set.
 * 
 * @note Many classes that could (although many times don't) use the
 *       configuration object make it a mandatory parameter.  This is
 *       because a configuration object should always be forwarded,
 *       otherwise, you run the risk of missing a parameter and then
 *       being stumped when a configuration directive doesn't work.
 * 
 * @todo Reconsider some of the public member variables
 */
class HTMLPurifier_Config
{
    
    /**
     * HTML Purifier's version
     */
    public $version = '3.1.1';
    
    /**
     * Bool indicator whether or not to automatically finalize 
     * the object if a read operation is done
     */
    public $autoFinalize = true;
    
    // protected member variables
    
    /**
     * Namespace indexed array of serials for specific namespaces (see
     * getSerial() for more info).
     */
    protected $serials = array();
    
    /**
     * Serial for entire configuration object
     */
    protected $serial;
    
    /**
     * Two-level associative array of configuration directives
     */
    protected $conf;
    
    /**
     * Parser for variables
     */
    protected $parser;
    
    /**
     * Reference HTMLPurifier_ConfigSchema for value checking
     * @note This is public for introspective purposes. Please don't
     *       abuse!
     */
    public $def;
    
    /**
     * Indexed array of definitions
     */
    protected $definitions;
    
    /**
     * Bool indicator whether or not config is finalized
     */
    protected $finalized = false;
    
    /**
     * @param $definition HTMLPurifier_ConfigSchema that defines what directives
     *                    are allowed.
     */
    public function __construct($definition) {
        $this->conf = $definition->defaults; // set up, copy in defaults
        $this->def  = $definition; // keep a copy around for checking
        $this->parser = new HTMLPurifier_VarParser_Flexible();
    }
    
    /**
     * Convenience constructor that creates a config object based on a mixed var
     * @param mixed $config Variable that defines the state of the config
     *                      object. Can be: a HTMLPurifier_Config() object,
     *                      an array of directives based on loadArray(),
     *                      or a string filename of an ini file.
     * @param HTMLPurifier_ConfigSchema Schema object
     * @return Configured HTMLPurifier_Config object
     */
    public static function create($config, $schema = null) {
        if ($config instanceof HTMLPurifier_Config) {
            // pass-through
            return $config;
        }
        if (!$schema) {
            $ret = HTMLPurifier_Config::createDefault();
        } else {
            $ret = new HTMLPurifier_Config($schema);
        }
        if (is_string($config)) $ret->loadIni($config);
        elseif (is_array($config)) $ret->loadArray($config);
        return $ret;
    }
    
    /**
     * Convenience constructor that creates a default configuration object.
     * @return Default HTMLPurifier_Config object.
     */
    public static function createDefault() {
        $definition = HTMLPurifier_ConfigSchema::instance();
        $config = new HTMLPurifier_Config($definition);
        return $config;
    }
    
    /**
     * Retreives a value from the configuration.
     * @param $namespace String namespace
     * @param $key String key
     */
    public function get($namespace, $key) {
        if (!$this->finalized && $this->autoFinalize) $this->finalize();
        if (!isset($this->def->info[$namespace][$key])) {
            // can't add % due to SimpleTest bug
            trigger_error('Cannot retrieve value of undefined directive ' . htmlspecialchars("$namespace.$key"),
                E_USER_WARNING);
            return;
        }
        if (isset($this->def->info[$namespace][$key]->isAlias)) {
            $d = $this->def->info[$namespace][$key];
            trigger_error('Cannot get value from aliased directive, use real name ' . $d->namespace . '.' . $d->name,
                E_USER_ERROR);
            return;
        }
        return $this->conf[$namespace][$key];
    }
    
    /**
     * Retreives an array of directives to values from a given namespace
     * @param $namespace String namespace
     */
    public function getBatch($namespace) {
        if (!$this->finalized && $this->autoFinalize) $this->finalize();
        if (!isset($this->def->info[$namespace])) {
            trigger_error('Cannot retrieve undefined namespace ' . htmlspecialchars($namespace),
                E_USER_WARNING);
            return;
        }
        return $this->conf[$namespace];
    }
    
    /**
     * Returns a md5 signature of a segment of the configuration object
     * that uniquely identifies that particular configuration
     * @note Revision is handled specially and is removed from the batch
     *       before processing!
     * @param $namespace Namespace to get serial for
     */
    public function getBatchSerial($namespace) {
        if (empty($this->serials[$namespace])) {
            $batch = $this->getBatch($namespace);
            unset($batch['DefinitionRev']);
            $this->serials[$namespace] = md5(serialize($batch));
        }
        return $this->serials[$namespace];
    }
    
    /**
     * Returns a md5 signature for the entire configuration object
     * that uniquely identifies that particular configuration
     */
    public function getSerial() {
        if (empty($this->serial)) {
            $this->serial = md5(serialize($this->getAll()));
        }
        return $this->serial;
    }
    
    /**
     * Retrieves all directives, organized by namespace
     */
    public function getAll() {
        if (!$this->finalized && $this->autoFinalize) $this->finalize();
        return $this->conf;
    }
    
    /**
     * Sets a value to configuration.
     * @param $namespace String namespace
     * @param $key String key
     * @param $value Mixed value
     */
    public function set($namespace, $key, $value, $from_alias = false) {
        if ($this->isFinalized('Cannot set directive after finalization')) return;
        if (!isset($this->def->info[$namespace][$key])) {
            trigger_error('Cannot set undefined directive ' . htmlspecialchars("$namespace.$key") . ' to value',
                E_USER_WARNING);
            return;
        }
        $def = $this->def->info[$namespace][$key];
        
        if (isset($def->isAlias)) {
            if ($from_alias) {
                trigger_error('Double-aliases not allowed, please fix '.
                    'ConfigSchema bug with' . "$namespace.$key", E_USER_ERROR);
                return;
            }
            $this->set($new_ns  = $def->namespace,
                       $new_dir = $def->name,
                       $value, true);
            trigger_error("$namespace.$key is an alias, preferred directive name is $new_ns.$new_dir", E_USER_NOTICE);
            return;
        }
        
        // Raw type might be negative when using the fully optimized form
        // of stdclass, which indicates allow_null == true
        $rtype = is_int($def) ? $def : $def->type;
        if ($rtype < 0) {
            $type = -$rtype;
            $allow_null = true;
        } else {
            $type = $rtype;
            $allow_null = isset($def->allow_null);
        }
        
        try {
            $value = $this->parser->parse($value, $type, $allow_null);
        } catch (HTMLPurifier_VarParserException $e) {
            trigger_error('Value for ' . "$namespace.$key" . ' is of invalid type, should be ' . HTMLPurifier_VarParser::getTypeName($type), E_USER_WARNING);
            return;
        }
        if (is_string($value) && is_object($def)) {
            // resolve value alias if defined
            if (isset($def->aliases[$value])) {
                $value = $def->aliases[$value];
            }
            // check to see if the value is allowed
            if (isset($def->allowed) && !isset($def->allowed[$value])) {
                trigger_error('Value not supported, valid values are: ' .
                    $this->_listify($def->allowed), E_USER_WARNING);
                return;
            }
        }
        $this->conf[$namespace][$key] = $value;
        
        // reset definitions if the directives they depend on changed
        // this is a very costly process, so it's discouraged 
        // with finalization
        if ($namespace == 'HTML' || $namespace == 'CSS') {
            $this->definitions[$namespace] = null;
        }
        
        $this->serials[$namespace] = false;
    }
    
    /**
     * Convenience function for error reporting
     */
    private function _listify($lookup) {
        $list = array();
        foreach ($lookup as $name => $b) $list[] = $name;
        return implode(', ', $list);
    }
    
    /**
     * Retrieves object reference to the HTML definition.
     * @param $raw Return a copy that has not been setup yet. Must be
     *             called before it's been setup, otherwise won't work.
     */
    public function getHTMLDefinition($raw = false) {
        return $this->getDefinition('HTML', $raw);
    }
    
    /**
     * Retrieves object reference to the CSS definition
     * @param $raw Return a copy that has not been setup yet. Must be
     *             called before it's been setup, otherwise won't work.
     */
    public function getCSSDefinition($raw = false) {
        return $this->getDefinition('CSS', $raw);
    }
    
    /**
     * Retrieves a definition
     * @param $type Type of definition: HTML, CSS, etc
     * @param $raw  Whether or not definition should be returned raw
     */
    public function getDefinition($type, $raw = false) {
        if (!$this->finalized && $this->autoFinalize) $this->finalize();
        $factory = HTMLPurifier_DefinitionCacheFactory::instance();
        $cache = $factory->create($type, $this);
        if (!$raw) {
            // see if we can quickly supply a definition
            if (!empty($this->definitions[$type])) {
                if (!$this->definitions[$type]->setup) {
                    $this->definitions[$type]->setup($this);
                    $cache->set($this->definitions[$type], $this);
                }
                return $this->definitions[$type];
            }
            // memory check missed, try cache
            $this->definitions[$type] = $cache->get($this);
            if ($this->definitions[$type]) {
                // definition in cache, return it
                return $this->definitions[$type];
            }
        } elseif (
            !empty($this->definitions[$type]) &&
            !$this->definitions[$type]->setup
        ) {
            // raw requested, raw in memory, quick return
            return $this->definitions[$type];
        }
        // quick checks failed, let's create the object
        if ($type == 'HTML') {
            $this->definitions[$type] = new HTMLPurifier_HTMLDefinition();
        } elseif ($type == 'CSS') {
            $this->definitions[$type] = new HTMLPurifier_CSSDefinition();
        } elseif ($type == 'URI') {
            $this->definitions[$type] = new HTMLPurifier_URIDefinition();
        } else {
            throw new HTMLPurifier_Exception("Definition of $type type not supported");
        }
        // quick abort if raw
        if ($raw) {
            if (is_null($this->get($type, 'DefinitionID'))) {
                // fatally error out if definition ID not set
                throw new HTMLPurifier_Exception("Cannot retrieve raw version without specifying %$type.DefinitionID");
            }
            return $this->definitions[$type];
        }
        // set it up
        $this->definitions[$type]->setup($this);
        // save in cache
        $cache->set($this->definitions[$type], $this);
        return $this->definitions[$type];
    }
    
    /**
     * Loads configuration values from an array with the following structure:
     * Namespace.Directive => Value
     * @param $config_array Configuration associative array
     */
    public function loadArray($config_array) {
        if ($this->isFinalized('Cannot load directives after finalization')) return;
        foreach ($config_array as $key => $value) {
            $key = str_replace('_', '.', $key);
            if (strpos($key, '.') !== false) {
                // condensed form
                list($namespace, $directive) = explode('.', $key);
                $this->set($namespace, $directive, $value);
            } else {
                $namespace = $key;
                $namespace_values = $value;
                foreach ($namespace_values as $directive => $value) {
                    $this->set($namespace, $directive, $value);
                }
            }
        }
    }
    
    /**
     * Returns a list of array(namespace, directive) for all directives
     * that are allowed in a web-form context as per an allowed
     * namespaces/directives list.
     * @param $allowed List of allowed namespaces/directives
     */
    public static function getAllowedDirectivesForForm($allowed, $schema = null) {
        if (!$schema) {
            $schema = HTMLPurifier_ConfigSchema::instance();
        }
        if ($allowed !== true) {
             if (is_string($allowed)) $allowed = array($allowed);
             $allowed_ns = array();
             $allowed_directives = array();
             $blacklisted_directives = array();
             foreach ($allowed as $ns_or_directive) {
                 if (strpos($ns_or_directive, '.') !== false) {
                     // directive
                     if ($ns_or_directive[0] == '-') {
                         $blacklisted_directives[substr($ns_or_directive, 1)] = true;
                     } else {
                         $allowed_directives[$ns_or_directive] = true;
                     }
                 } else {
                     // namespace
                     $allowed_ns[$ns_or_directive] = true;
                 }
             }
        }
        $ret = array();
        foreach ($schema->info as $ns => $keypairs) {
            foreach ($keypairs as $directive => $def) {
                if ($allowed !== true) {
                    if (isset($blacklisted_directives["$ns.$directive"])) continue;
                    if (!isset($allowed_directives["$ns.$directive"]) && !isset($allowed_ns[$ns])) continue;
                }
                if (isset($def->isAlias)) continue;
                if ($directive == 'DefinitionID' || $directive == 'DefinitionRev') continue;
                $ret[] = array($ns, $directive);
            }
        }
        return $ret;
    }
    
    /**
     * Loads configuration values from $_GET/$_POST that were posted
     * via ConfigForm
     * @param $array $_GET or $_POST array to import
     * @param $index Index/name that the config variables are in
     * @param $allowed List of allowed namespaces/directives 
     * @param $mq_fix Boolean whether or not to enable magic quotes fix
     * @param $schema Instance of HTMLPurifier_ConfigSchema to use, if not global copy
     */
    public static function loadArrayFromForm($array, $index = false, $allowed = true, $mq_fix = true, $schema = null) {
        $ret = HTMLPurifier_Config::prepareArrayFromForm($array, $index, $allowed, $mq_fix, $schema);
        $config = HTMLPurifier_Config::create($ret, $schema);
        return $config;
    }
    
    /**
     * Merges in configuration values from $_GET/$_POST to object. NOT STATIC.
     * @note Same parameters as loadArrayFromForm
     */
    public function mergeArrayFromForm($array, $index = false, $allowed = true, $mq_fix = true) {
         $ret = HTMLPurifier_Config::prepareArrayFromForm($array, $index, $allowed, $mq_fix, $this->def);
         $this->loadArray($ret);
    }
    
    /**
     * Prepares an array from a form into something usable for the more
     * strict parts of HTMLPurifier_Config
     */
    public static function prepareArrayFromForm($array, $index = false, $allowed = true, $mq_fix = true, $schema = null) {
        if ($index !== false) $array = (isset($array[$index]) && is_array($array[$index])) ? $array[$index] : array();
        $mq = $mq_fix && function_exists('get_magic_quotes_gpc') && get_magic_quotes_gpc();
        
        $allowed = HTMLPurifier_Config::getAllowedDirectivesForForm($allowed, $schema);
        $ret = array();
        foreach ($allowed as $key) {
            list($ns, $directive) = $key;
            $skey = "$ns.$directive";
            if (!empty($array["Null_$skey"])) {
                $ret[$ns][$directive] = null;
                continue;
            }
            if (!isset($array[$skey])) continue;
            $value = $mq ? stripslashes($array[$skey]) : $array[$skey];
            $ret[$ns][$directive] = $value;
        }
        return $ret;
    }
    
    /**
     * Loads configuration values from an ini file
     * @param $filename Name of ini file
     */
    public function loadIni($filename) {
        if ($this->isFinalized('Cannot load directives after finalization')) return;
        $array = parse_ini_file($filename, true);
        $this->loadArray($array);
    }
    
    /**
     * Checks whether or not the configuration object is finalized.
     * @param $error String error message, or false for no error
     */
    public function isFinalized($error = false) {
        if ($this->finalized && $error) {
            trigger_error($error, E_USER_ERROR);
        }
        return $this->finalized;
    }
    
    /**
     * Finalizes configuration only if auto finalize is on and not
     * already finalized
     */
    public function autoFinalize() {
        if (!$this->finalized && $this->autoFinalize) $this->finalize();
    }
    
    /**
     * Finalizes a configuration object, prohibiting further change
     */
    public function finalize() {
        $this->finalized = true;
    }
    
}






/**
 * Configuration definition, defines directives and their defaults.
 */
class HTMLPurifier_ConfigSchema {
    
    /**
     * Defaults of the directives and namespaces.
     * @note This shares the exact same structure as HTMLPurifier_Config::$conf
     */
    public $defaults = array();
    
    /**
     * Definition of the directives. The structure of this is:
     * 
     *  array(
     *      'Namespace' => array(
     *          'Directive' => new stdclass(),
     *      )
     *  )
     * 
     * The stdclass may have the following properties:
     * 
     *  - If isAlias isn't set:
     *      - type: Integer type of directive, see HTMLPurifier_VarParser for definitions
     *      - allow_null: If set, this directive allows null values
     *      - aliases: If set, an associative array of value aliases to real values
     *      - allowed: If set, a lookup array of allowed (string) values
     *  - If isAlias is set:
     *      - namespace: Namespace this directive aliases to
     *      - name: Directive name this directive aliases to
     * 
     * In certain degenerate cases, stdclass will actually be an integer. In
     * that case, the value is equivalent to an stdclass with the type
     * property set to the integer. If the integer is negative, type is
     * equal to the absolute value of integer, and allow_null is true.
     * 
     * This class is friendly with HTMLPurifier_Config. If you need introspection
     * about the schema, you're better of using the ConfigSchema_Interchange,
     * which uses more memory but has much richer information.
     */
    public $info = array();
    
    /**
     * Application-wide singleton
     */
    static protected $singleton;
    
    /**
     * Unserializes the default ConfigSchema.
     */
    public static function makeFromSerial() {
        return unserialize(file_get_contents(HTMLPURIFIER_PREFIX . '/HTMLPurifier/ConfigSchema/schema.ser'));
    }
    
    /**
     * Retrieves an instance of the application-wide configuration definition.
     */
    public static function instance($prototype = null) {
        if ($prototype !== null) {
            HTMLPurifier_ConfigSchema::$singleton = $prototype;
        } elseif (HTMLPurifier_ConfigSchema::$singleton === null || $prototype === true) {
            HTMLPurifier_ConfigSchema::$singleton = HTMLPurifier_ConfigSchema::makeFromSerial();
        }
        return HTMLPurifier_ConfigSchema::$singleton;
    }
    
    /**
     * Defines a directive for configuration
     * @warning Will fail of directive's namespace is defined.
     * @warning This method's signature is slightly different from the legacy
     *          define() static method! Beware!
     * @param $namespace Namespace the directive is in
     * @param $name Key of directive
     * @param $default Default value of directive
     * @param $type Allowed type of the directive. See
     *      HTMLPurifier_DirectiveDef::$type for allowed values
     * @param $allow_null Whether or not to allow null values
     */
    public function add($namespace, $name, $default, $type, $allow_null) {
        $obj = new stdclass();
        $obj->type = is_int($type) ? $type : HTMLPurifier_VarParser::$types[$type];
        if ($allow_null) $obj->allow_null = true;
        $this->info[$namespace][$name] = $obj;
        $this->defaults[$namespace][$name] = $default;
    }
    
    /**
     * Defines a namespace for directives to be put into.
     * @warning This is slightly different from the corresponding static
     *          method.
     * @param $namespace Namespace's name
     */
    public function addNamespace($namespace) {
        $this->info[$namespace] = array();
        $this->defaults[$namespace] = array();
    }
    
    /**
     * Defines a directive value alias.
     * 
     * Directive value aliases are convenient for developers because it lets
     * them set a directive to several values and get the same result.
     * @param $namespace Directive's namespace
     * @param $name Name of Directive
     * @param $aliases Hash of aliased values to the real alias
     */
    public function addValueAliases($namespace, $name, $aliases) {
        if (!isset($this->info[$namespace][$name]->aliases)) {
            $this->info[$namespace][$name]->aliases = array();
        }
        foreach ($aliases as $alias => $real) {
            $this->info[$namespace][$name]->aliases[$alias] = $real;
        }
    }
    
    /**
     * Defines a set of allowed values for a directive.
     * @warning This is slightly different from the corresponding static
     *          method definition.
     * @param $namespace Namespace of directive
     * @param $name Name of directive
     * @param $allowed Lookup array of allowed values
     */
    public function addAllowedValues($namespace, $name, $allowed) {
        $this->info[$namespace][$name]->allowed = $allowed;
    }
    
    /**
     * Defines a directive alias for backwards compatibility
     * @param $namespace
     * @param $name Directive that will be aliased
     * @param $new_namespace
     * @param $new_name Directive that the alias will be to
     */
    public function addAlias($namespace, $name, $new_namespace, $new_name) {
        $obj = new stdclass;
        $obj->namespace = $new_namespace;
        $obj->name = $new_name;
        $obj->isAlias = true;
        $this->info[$namespace][$name] = $obj;
    }
    
    /**
     * Replaces any stdclass that only has the type property with type integer.
     */
    public function postProcess() {
        foreach ($this->info as $namespace => $info) {
            foreach ($info as $directive => $v) {
                if (count((array) $v) == 1) {
                    $this->info[$namespace][$directive] = $v->type;
                } elseif (count((array) $v) == 2 && isset($v->allow_null)) {
                    $this->info[$namespace][$directive] = -$v->type;
                }
            }
        }
    }
    
    // DEPRECATED METHODS
    
    /** @see HTMLPurifier_ConfigSchema->set() */
    public static function define($namespace, $name, $default, $type, $description) {
        HTMLPurifier_ConfigSchema::deprecated(__METHOD__);
        $type_values = explode('/', $type, 2);
        $type = $type_values[0];
        $modifier = isset($type_values[1]) ? $type_values[1] : false;
        $allow_null = ($modifier === 'null');
        $def = HTMLPurifier_ConfigSchema::instance();
        $def->add($namespace, $name, $default, $type, $allow_null);
    }
    
    /** @see HTMLPurifier_ConfigSchema->addNamespace() */
    public static function defineNamespace($namespace, $description) {
        HTMLPurifier_ConfigSchema::deprecated(__METHOD__);
        $def = HTMLPurifier_ConfigSchema::instance();
        $def->addNamespace($namespace);
    }
    
    /** @see HTMLPurifier_ConfigSchema->addValueAliases() */
    public static function defineValueAliases($namespace, $name, $aliases) {
        HTMLPurifier_ConfigSchema::deprecated(__METHOD__);
        $def = HTMLPurifier_ConfigSchema::instance();
        $def->addValueAliases($namespace, $name, $aliases);
    }
    
    /** @see HTMLPurifier_ConfigSchema->addAllowedValues() */
    public static function defineAllowedValues($namespace, $name, $allowed_values) {
        HTMLPurifier_ConfigSchema::deprecated(__METHOD__);
        $allowed = array();
        foreach ($allowed_values as $value) {
            $allowed[$value] = true;
        }
        $def = HTMLPurifier_ConfigSchema::instance();
        $def->addAllowedValues($namespace, $name, $allowed);
    }
    
    /** @see HTMLPurifier_ConfigSchema->addAlias() */
    public static function defineAlias($namespace, $name, $new_namespace, $new_name) {
        HTMLPurifier_ConfigSchema::deprecated(__METHOD__);
        $def = HTMLPurifier_ConfigSchema::instance();
        $def->addAlias($namespace, $name, $new_namespace, $new_name);
    }
    
    /** @deprecated, use HTMLPurifier_VarParser->parse() */
    public function validate($a, $b, $c = false) {
        trigger_error("HTMLPurifier_ConfigSchema->validate deprecated, use HTMLPurifier_VarParser->parse instead", E_USER_NOTICE);
        $parser = new HTMLPurifier_VarParser();
        return $parser->parse($a, $b, $c);
    }
    
    /**
     * Throws an E_USER_NOTICE stating that a method is deprecated.
     */
    private static function deprecated($method) {
        trigger_error("Static HTMLPurifier_ConfigSchema::$method deprecated, use add*() method instead", E_USER_NOTICE);
    }
    
}





/**
 * @todo Unit test
 */
class HTMLPurifier_ContentSets
{
    
    /**
     * List of content set strings (pipe seperators) indexed by name.
     */
    public $info = array();
    
    /**
     * List of content set lookups (element => true) indexed by name.
     * @note This is in HTMLPurifier_HTMLDefinition->info_content_sets
     */
    public $lookup = array();
    
    /**
     * Synchronized list of defined content sets (keys of info)
     */
    protected $keys = array();
    /**
     * Synchronized list of defined content values (values of info)
     */
    protected $values = array();
    
    /**
     * Merges in module's content sets, expands identifiers in the content
     * sets and populates the keys, values and lookup member variables.
     * @param $modules List of HTMLPurifier_HTMLModule
     */
    public function __construct($modules) {
        if (!is_array($modules)) $modules = array($modules);
        // populate content_sets based on module hints
        // sorry, no way of overloading
        foreach ($modules as $module_i => $module) {
            foreach ($module->content_sets as $key => $value) {
                if (isset($this->info[$key])) {
                    // add it into the existing content set
                    $this->info[$key] = $this->info[$key] . ' | ' . $value;
                } else {
                    $this->info[$key] = $value;
                }
            }
        }
        // perform content_set expansions
        $this->keys = array_keys($this->info);
        foreach ($this->info as $i => $set) {
            // only performed once, so infinite recursion is not
            // a problem
            $this->info[$i] =
                str_replace(
                    $this->keys,
                    // must be recalculated each time due to
                    // changing substitutions
                    array_values($this->info),
                $set);
        }
        $this->values = array_values($this->info);
        
        // generate lookup tables
        foreach ($this->info as $name => $set) {
            $this->lookup[$name] = $this->convertToLookup($set);
        }
    }
    
    /**
     * Accepts a definition; generates and assigns a ChildDef for it
     * @param $def HTMLPurifier_ElementDef reference
     * @param $module Module that defined the ElementDef
     */
    public function generateChildDef(&$def, $module) {
        if (!empty($def->child)) return; // already done!
        $content_model = $def->content_model;
        if (is_string($content_model)) {
            $def->content_model = str_replace(
                $this->keys, $this->values, $content_model);
        }
        $def->child = $this->getChildDef($def, $module);
    }
    
    /**
     * Instantiates a ChildDef based on content_model and content_model_type
     * member variables in HTMLPurifier_ElementDef
     * @note This will also defer to modules for custom HTMLPurifier_ChildDef
     *       subclasses that need content set expansion
     * @param $def HTMLPurifier_ElementDef to have ChildDef extracted
     * @return HTMLPurifier_ChildDef corresponding to ElementDef
     */
    public function getChildDef($def, $module) {
        $value = $def->content_model;
        if (is_object($value)) {
            trigger_error(
                'Literal object child definitions should be stored in '.
                'ElementDef->child not ElementDef->content_model',
                E_USER_NOTICE
            );
            return $value;
        }
        switch ($def->content_model_type) {
            case 'required':
                return new HTMLPurifier_ChildDef_Required($value);
            case 'optional':
                return new HTMLPurifier_ChildDef_Optional($value);
            case 'empty':
                return new HTMLPurifier_ChildDef_Empty();
            case 'custom':
                return new HTMLPurifier_ChildDef_Custom($value);
        }
        // defer to its module
        $return = false;
        if ($module->defines_child_def) { // save a func call
            $return = $module->getChildDef($def);
        }
        if ($return !== false) return $return;
        // error-out
        trigger_error(
            'Could not determine which ChildDef class to instantiate',
            E_USER_ERROR
        );
        return false;
    }
    
    /**
     * Converts a string list of elements separated by pipes into
     * a lookup array.
     * @param $string List of elements
     * @return Lookup array of elements
     */
    protected function convertToLookup($string) {
        $array = explode('|', str_replace(' ', '', $string));
        $ret = array();
        foreach ($array as $i => $k) {
            $ret[$k] = true;
        }
        return $ret;
    }
    
}




/**
 * Registry object that contains information about the current context.
 * @warning Is a bit buggy when variables are set to null: it thinks
 *          they don't exist! So use false instead, please.
 * @note Since the variables Context deals with may not be objects,
 *       references are very important here! Do not remove!
 */
class HTMLPurifier_Context
{
    
    /**
     * Private array that stores the references.
     */
    private $_storage = array();
    
    /**
     * Registers a variable into the context.
     * @param $name String name
     * @param $ref Reference to variable to be registered
     */
    public function register($name, &$ref) {
        if (isset($this->_storage[$name])) {
            trigger_error("Name $name produces collision, cannot re-register",
                          E_USER_ERROR);
            return;
        }
        $this->_storage[$name] =& $ref;
    }
    
    /**
     * Retrieves a variable reference from the context.
     * @param $name String name
     * @param $ignore_error Boolean whether or not to ignore error
     */
    public function &get($name, $ignore_error = false) {
        if (!isset($this->_storage[$name])) {
            if (!$ignore_error) {
                trigger_error("Attempted to retrieve non-existent variable $name",
                              E_USER_ERROR);
            }
            $var = null; // so we can return by reference
            return $var;
        }
        return $this->_storage[$name];
    }
    
    /**
     * Destorys a variable in the context.
     * @param $name String name
     */
    public function destroy($name) {
        if (!isset($this->_storage[$name])) {
            trigger_error("Attempted to destroy non-existent variable $name",
                          E_USER_ERROR);
            return;
        }
        unset($this->_storage[$name]);
    }
    
    /**
     * Checks whether or not the variable exists.
     * @param $name String name
     */
    public function exists($name) {
        return isset($this->_storage[$name]);
    }
    
    /**
     * Loads a series of variables from an associative array
     * @param $context_array Assoc array of variables to load
     */
    public function loadArray($context_array) {
        foreach ($context_array as $key => $discard) {
            $this->register($key, $context_array[$key]);
        }
    }
    
}




/**
 * Abstract class representing Definition cache managers that implements
 * useful common methods and is a factory.
 * @todo Create a separate maintenance file advanced users can use to
 *       cache their custom HTMLDefinition, which can be loaded
 *       via a configuration directive
 * @todo Implement memcached
 */
abstract class HTMLPurifier_DefinitionCache
{
    
    public $type;
    
    /**
     * @param $name Type of definition objects this instance of the
     *      cache will handle.
     */
    public function __construct($type) {
        $this->type = $type;
    }
    
    /**
     * Generates a unique identifier for a particular configuration
     * @param Instance of HTMLPurifier_Config
     */
    public function generateKey($config) {
        return $config->version . ',' . // possibly replace with function calls
               $config->getBatchSerial($this->type) . ',' .
               $config->get($this->type, 'DefinitionRev');
    }
    
    /**
     * Tests whether or not a key is old with respect to the configuration's
     * version and revision number.
     * @param $key Key to test
     * @param $config Instance of HTMLPurifier_Config to test against
     */
    public function isOld($key, $config) {
        if (substr_count($key, ',') < 2) return true;
        list($version, $hash, $revision) = explode(',', $key, 3);
        $compare = version_compare($version, $config->version);
        // version mismatch, is always old
        if ($compare != 0) return true;
        // versions match, ids match, check revision number
        if (
            $hash == $config->getBatchSerial($this->type) &&
            $revision < $config->get($this->type, 'DefinitionRev')
        ) return true;
        return false;
    }
    
    /**
     * Checks if a definition's type jives with the cache's type
     * @note Throws an error on failure
     * @param $def Definition object to check
     * @return Boolean true if good, false if not
     */
    public function checkDefType($def) {
        if ($def->type !== $this->type) {
            trigger_error("Cannot use definition of type {$def->type} in cache for {$this->type}");
            return false;
        }
        return true;
    }
    
    /**
     * Adds a definition object to the cache
     */
    abstract public function add($def, $config);
    
    /**
     * Unconditionally saves a definition object to the cache
     */
    abstract public function set($def, $config);
    
    /**
     * Replace an object in the cache
     */
    abstract public function replace($def, $config);
    
    /**
     * Retrieves a definition object from the cache
     */
    abstract public function get($config);
    
    /**
     * Removes a definition object to the cache
     */
    abstract public function remove($config);
    
    /**
     * Clears all objects from cache
     */
    abstract public function flush($config);
    
    /**
     * Clears all expired (older version or revision) objects from cache
     * @note Be carefuly implementing this method as flush. Flush must
     *       not interfere with other Definition types, and cleanup()
     *       should not be repeatedly called by userland code.
     */
    abstract public function cleanup($config);
    
}




/**
 * Responsible for creating definition caches.
 */
class HTMLPurifier_DefinitionCacheFactory
{
    
    protected $caches = array('Serializer' => array());
    protected $implementations = array();
    protected $decorators = array();
    
    /**
     * Initialize default decorators
     */
    public function setup() {
        $this->addDecorator('Cleanup');
    }
    
    /**
     * Retrieves an instance of global definition cache factory.
     */
    public static function instance($prototype = null) {
        static $instance;
        if ($prototype !== null) {
            $instance = $prototype;
        } elseif ($instance === null || $prototype === true) {
            $instance = new HTMLPurifier_DefinitionCacheFactory();
            $instance->setup();
        }
        return $instance;
    }
    
    /**
     * Registers a new definition cache object
     * @param $short Short name of cache object, for reference
     * @param $long Full class name of cache object, for construction 
     */
    public function register($short, $long) {
        $this->implementations[$short] = $long;
    }
    
    /**
     * Factory method that creates a cache object based on configuration
     * @param $name Name of definitions handled by cache
     * @param $config Instance of HTMLPurifier_Config
     */
    public function create($type, $config) {
        $method = $config->get('Cache', 'DefinitionImpl');
        if ($method === null) {
            return new HTMLPurifier_DefinitionCache_Null($type);
        }
        if (!empty($this->caches[$method][$type])) {
            return $this->caches[$method][$type];
        }
        if (
          isset($this->implementations[$method]) &&
          class_exists($class = $this->implementations[$method], false)
        ) {
            $cache = new $class($type);
        } else {
            if ($method != 'Serializer') {
                trigger_error("Unrecognized DefinitionCache $method, using Serializer instead", E_USER_WARNING);
            }
            $cache = new HTMLPurifier_DefinitionCache_Serializer($type);
        }
        foreach ($this->decorators as $decorator) {
            $new_cache = $decorator->decorate($cache);
            // prevent infinite recursion in PHP 4
            unset($cache);
            $cache = $new_cache;
        }
        $this->caches[$method][$type] = $cache;
        return $this->caches[$method][$type];
    }
    
    /**
     * Registers a decorator to add to all new cache objects
     * @param 
     */
    public function addDecorator($decorator) {
        if (is_string($decorator)) {
            $class = "HTMLPurifier_DefinitionCache_Decorator_$decorator";
            $decorator = new $class;
        }
        $this->decorators[$decorator->name] = $decorator;
    }
    
}




/**
 * Represents a document type, contains information on which modules
 * need to be loaded.
 * @note This class is inspected by Printer_HTMLDefinition->renderDoctype.
 *       If structure changes, please update that function.
 */
class HTMLPurifier_Doctype
{
    /**
     * Full name of doctype
     */
    public $name;
    
    /**
     * List of standard modules (string identifiers or literal objects)
     * that this doctype uses
     */
    public $modules = array();
    
    /**
     * List of modules to use for tidying up code
     */
    public $tidyModules = array();
    
    /**
     * Is the language derived from XML (i.e. XHTML)?
     */
    public $xml = true;
    
    /**
     * List of aliases for this doctype
     */
    public $aliases = array();
    
    /**
     * Public DTD identifier
     */
    public $dtdPublic;
    
    /**
     * System DTD identifier
     */
    public $dtdSystem;
    
    public function __construct($name = null, $xml = true, $modules = array(),
        $tidyModules = array(), $aliases = array(), $dtd_public = null, $dtd_system = null
    ) {
        $this->name         = $name;
        $this->xml          = $xml;
        $this->modules      = $modules;
        $this->tidyModules  = $tidyModules;
        $this->aliases      = $aliases;
        $this->dtdPublic    = $dtd_public;
        $this->dtdSystem    = $dtd_system;
    }
}




class HTMLPurifier_DoctypeRegistry
{
    
    /**
     * Hash of doctype names to doctype objects
     */
    protected $doctypes;
    
    /**
     * Lookup table of aliases to real doctype names
     */
    protected $aliases;
    
    /**
     * Registers a doctype to the registry
     * @note Accepts a fully-formed doctype object, or the
     *       parameters for constructing a doctype object
     * @param $doctype Name of doctype or literal doctype object
     * @param $modules Modules doctype will load
     * @param $modules_for_modes Modules doctype will load for certain modes
     * @param $aliases Alias names for doctype
     * @return Editable registered doctype
     */
    public function register($doctype, $xml = true, $modules = array(),
        $tidy_modules = array(), $aliases = array(), $dtd_public = null, $dtd_system = null
    ) {
        if (!is_array($modules)) $modules = array($modules);
        if (!is_array($tidy_modules)) $tidy_modules = array($tidy_modules);
        if (!is_array($aliases)) $aliases = array($aliases);
        if (!is_object($doctype)) {
            $doctype = new HTMLPurifier_Doctype(
                $doctype, $xml, $modules, $tidy_modules, $aliases, $dtd_public, $dtd_system
            );
        }
        $this->doctypes[$doctype->name] = $doctype;
        $name = $doctype->name;
        // hookup aliases
        foreach ($doctype->aliases as $alias) {
            if (isset($this->doctypes[$alias])) continue;
            $this->aliases[$alias] = $name;
        }
        // remove old aliases
        if (isset($this->aliases[$name])) unset($this->aliases[$name]);
        return $doctype;
    }
    
    /**
     * Retrieves reference to a doctype of a certain name
     * @note This function resolves aliases
     * @note When possible, use the more fully-featured make()
     * @param $doctype Name of doctype
     * @return Editable doctype object
     */
    public function get($doctype) {
        if (isset($this->aliases[$doctype])) $doctype = $this->aliases[$doctype];
        if (!isset($this->doctypes[$doctype])) {
            trigger_error('Doctype ' . htmlspecialchars($doctype) . ' does not exist', E_USER_ERROR);
            $anon = new HTMLPurifier_Doctype($doctype);
            return $anon;
        }
        return $this->doctypes[$doctype];
    }
    
    /**
     * Creates a doctype based on a configuration object,
     * will perform initialization on the doctype
     * @note Use this function to get a copy of doctype that config
     *       can hold on to (this is necessary in order to tell
     *       Generator whether or not the current document is XML
     *       based or not).
     */
    public function make($config) {
        return clone $this->get($this->getDoctypeFromConfig($config));
    }
    
    /**
     * Retrieves the doctype from the configuration object
     */
    public function getDoctypeFromConfig($config) {
        // recommended test
        $doctype = $config->get('HTML', 'Doctype');
        if (!empty($doctype)) return $doctype;
        $doctype = $config->get('HTML', 'CustomDoctype');
        if (!empty($doctype)) return $doctype;
        // backwards-compatibility
        if ($config->get('HTML', 'XHTML')) {
            $doctype = 'XHTML 1.0';
        } else {
            $doctype = 'HTML 4.01';
        }
        if ($config->get('HTML', 'Strict')) {
            $doctype .= ' Strict';
        } else {
            $doctype .= ' Transitional';
        }
        return $doctype;
    }
    
}




/**
 * Structure that stores an HTML element definition. Used by
 * HTMLPurifier_HTMLDefinition and HTMLPurifier_HTMLModule.
 * @note This class is inspected by HTMLPurifier_Printer_HTMLDefinition.
 *       Please update that class too.
 */
class HTMLPurifier_ElementDef
{
    
    /**
     * Does the definition work by itself, or is it created solely
     * for the purpose of merging into another definition?
     */
    public $standalone = true;
    
    /**
     * Associative array of attribute name to HTMLPurifier_AttrDef
     * @note Before being processed by HTMLPurifier_AttrCollections
     *       when modules are finalized during
     *       HTMLPurifier_HTMLDefinition->setup(), this array may also
     *       contain an array at index 0 that indicates which attribute
     *       collections to load into the full array. It may also
     *       contain string indentifiers in lieu of HTMLPurifier_AttrDef,
     *       see HTMLPurifier_AttrTypes on how they are expanded during
     *       HTMLPurifier_HTMLDefinition->setup() processing.
     */
    public $attr = array();
    
    /**
     * Indexed list of tag's HTMLPurifier_AttrTransform to be done before validation
     */
    public $attr_transform_pre = array();
    
    /**
     * Indexed list of tag's HTMLPurifier_AttrTransform to be done after validation
     */
    public $attr_transform_post = array();
    
    /**
     * HTMLPurifier_ChildDef of this tag.
     */
    public $child;
    
    /**
     * Abstract string representation of internal ChildDef rules. See
     * HTMLPurifier_ContentSets for how this is parsed and then transformed
     * into an HTMLPurifier_ChildDef.
     * @warning This is a temporary variable that is not available after
     *      being processed by HTMLDefinition
     */
    public $content_model;
    
    /**
     * Value of $child->type, used to determine which ChildDef to use,
     * used in combination with $content_model.
     * @warning This must be lowercase
     * @warning This is a temporary variable that is not available after
     *      being processed by HTMLDefinition
     */
    public $content_model_type;
    
    
    
    /**
     * Does the element have a content model (#PCDATA | Inline)*? This
     * is important for chameleon ins and del processing in 
     * HTMLPurifier_ChildDef_Chameleon. Dynamically set: modules don't
     * have to worry about this one.
     */
    public $descendants_are_inline = false;
    
    /**
     * List of the names of required attributes this element has. Dynamically
     * populated by HTMLPurifier_HTMLDefinition::getElement
     */
    public $required_attr = array();
    
    /**
     * Lookup table of tags excluded from all descendants of this tag.
     * @note SGML permits exclusions for all descendants, but this is
     *       not possible with DTDs or XML Schemas. W3C has elected to
     *       use complicated compositions of content_models to simulate
     *       exclusion for children, but we go the simpler, SGML-style
     *       route of flat-out exclusions, which correctly apply to
     *       all descendants and not just children. Note that the XHTML
     *       Modularization Abstract Modules are blithely unaware of such
     *       distinctions.
     */
    public $excludes = array();
    
    /**
     * Low-level factory constructor for creating new standalone element defs
     */
    public static function create($content_model, $content_model_type, $attr) {
        $def = new HTMLPurifier_ElementDef();
        $def->content_model = $content_model;
        $def->content_model_type = $content_model_type;
        $def->attr = $attr;
        return $def;
    }
    
    /**
     * Merges the values of another element definition into this one.
     * Values from the new element def take precedence if a value is
     * not mergeable.
     */
    public function mergeIn($def) {
        
        // later keys takes precedence
        foreach($def->attr as $k => $v) {
            if ($k === 0) {
                // merge in the includes
                // sorry, no way to override an include
                foreach ($v as $v2) {
                    $this->attr[0][] = $v2;
                }
                continue;
            }
            if ($v === false) {
                if (isset($this->attr[$k])) unset($this->attr[$k]);
                continue;
            }
            $this->attr[$k] = $v;
        }
        $this->_mergeAssocArray($this->attr_transform_pre, $def->attr_transform_pre);
        $this->_mergeAssocArray($this->attr_transform_post, $def->attr_transform_post);
        $this->_mergeAssocArray($this->excludes, $def->excludes);
        
        if(!empty($def->content_model)) {
            $this->content_model .= ' | ' . $def->content_model;
            $this->child = false;
        }
        if(!empty($def->content_model_type)) {
            $this->content_model_type = $def->content_model_type;
            $this->child = false;
        }
        if(!is_null($def->child)) $this->child = $def->child;
        if($def->descendants_are_inline) $this->descendants_are_inline = $def->descendants_are_inline;
        
    }
    
    /**
     * Merges one array into another, removes values which equal false
     * @param $a1 Array by reference that is merged into
     * @param $a2 Array that merges into $a1
     */
    private function _mergeAssocArray(&$a1, $a2) {
        foreach ($a2 as $k => $v) {
            if ($v === false) {
                if (isset($a1[$k])) unset($a1[$k]);
                continue;
            }
            $a1[$k] = $v;
        }
    }
    
}





/**
 * A UTF-8 specific character encoder that handles cleaning and transforming.
 * @note All functions in this class should be static.
 */
class HTMLPurifier_Encoder
{
    
    /**
     * Constructor throws fatal error if you attempt to instantiate class
     */
    private function __construct() {
        trigger_error('Cannot instantiate encoder, call methods statically', E_USER_ERROR);
    }
    
    /**
     * Error-handler that mutes errors, alternative to shut-up operator.
     */
    private static function muteErrorHandler() {}
    
    /**
     * Cleans a UTF-8 string for well-formedness and SGML validity
     * 
     * It will parse according to UTF-8 and return a valid UTF8 string, with
     * non-SGML codepoints excluded.
     * 
     * @note Just for reference, the non-SGML code points are 0 to 31 and
     *       127 to 159, inclusive.  However, we allow code points 9, 10
     *       and 13, which are the tab, line feed and carriage return
     *       respectively. 128 and above the code points map to multibyte
     *       UTF-8 representations.
     * 
     * @note Fallback code adapted from utf8ToUnicode by Henri Sivonen and
     *       hsivonen@iki.fi at <http://iki.fi/hsivonen/php-utf8/> under the
     *       LGPL license.  Notes on what changed are inside, but in general,
     *       the original code transformed UTF-8 text into an array of integer
     *       Unicode codepoints. Understandably, transforming that back to
     *       a string would be somewhat expensive, so the function was modded to
     *       directly operate on the string.  However, this discourages code
     *       reuse, and the logic enumerated here would be useful for any
     *       function that needs to be able to understand UTF-8 characters.
     *       As of right now, only smart lossless character encoding converters
     *       would need that, and I'm probably not going to implement them.
     *       Once again, PHP 6 should solve all our problems.
     */
    public static function cleanUTF8($str, $force_php = false) {
        
        // UTF-8 validity is checked since PHP 4.3.5
        // This is an optimization: if the string is already valid UTF-8, no
        // need to do PHP stuff. 99% of the time, this will be the case.
        // The regexp matches the XML char production, as well as well as excluding
        // non-SGML codepoints U+007F to U+009F
        if (preg_match('/^[\x{9}\x{A}\x{D}\x{20}-\x{7E}\x{A0}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF}]*$/Du', $str)) {
            return $str;
        }
        
        $mState = 0; // cached expected number of octets after the current octet
                     // until the beginning of the next UTF8 character sequence
        $mUcs4  = 0; // cached Unicode character
        $mBytes = 1; // cached expected number of octets in the current sequence
        
        // original code involved an $out that was an array of Unicode
        // codepoints.  Instead of having to convert back into UTF-8, we've
        // decided to directly append valid UTF-8 characters onto a string
        // $out once they're done.  $char accumulates raw bytes, while $mUcs4
        // turns into the Unicode code point, so there's some redundancy.
        
        $out = '';
        $char = '';
        
        $len = strlen($str);
        for($i = 0; $i < $len; $i++) {
            $in = ord($str{$i});
            $char .= $str[$i]; // append byte to char
            if (0 == $mState) {
                // When mState is zero we expect either a US-ASCII character 
                // or a multi-octet sequence.
                if (0 == (0x80 & ($in))) {
                    // US-ASCII, pass straight through.
                    if (($in <= 31 || $in == 127) && 
                        !($in == 9 || $in == 13 || $in == 10) // save \r\t\n
                    ) {
                        // control characters, remove
                    } else {
                        $out .= $char;
                    }
                    // reset
                    $char = '';
                    $mBytes = 1;
                } elseif (0xC0 == (0xE0 & ($in))) {
                    // First octet of 2 octet sequence
                    $mUcs4 = ($in);
                    $mUcs4 = ($mUcs4 & 0x1F) << 6;
                    $mState = 1;
                    $mBytes = 2;
                } elseif (0xE0 == (0xF0 & ($in))) {
                    // First octet of 3 octet sequence
                    $mUcs4 = ($in);
                    $mUcs4 = ($mUcs4 & 0x0F) << 12;
                    $mState = 2;
                    $mBytes = 3;
                } elseif (0xF0 == (0xF8 & ($in))) {
                    // First octet of 4 octet sequence
                    $mUcs4 = ($in);
                    $mUcs4 = ($mUcs4 & 0x07) << 18;
                    $mState = 3;
                    $mBytes = 4;
                } elseif (0xF8 == (0xFC & ($in))) {
                    // First octet of 5 octet sequence.
                    // 
                    // This is illegal because the encoded codepoint must be 
                    // either:
                    // (a) not the shortest form or
                    // (b) outside the Unicode range of 0-0x10FFFF.
                    // Rather than trying to resynchronize, we will carry on 
                    // until the end of the sequence and let the later error
                    // handling code catch it.
                    $mUcs4 = ($in);
                    $mUcs4 = ($mUcs4 & 0x03) << 24;
                    $mState = 4;
                    $mBytes = 5;
                } elseif (0xFC == (0xFE & ($in))) {
                    // First octet of 6 octet sequence, see comments for 5
                    // octet sequence.
                    $mUcs4 = ($in);
                    $mUcs4 = ($mUcs4 & 1) << 30;
                    $mState = 5;
                    $mBytes = 6;
                } else {
                    // Current octet is neither in the US-ASCII range nor a 
                    // legal first octet of a multi-octet sequence.
                    $mState = 0;
                    $mUcs4  = 0;
                    $mBytes = 1;
                    $char = '';
                }
            } else {
                // When mState is non-zero, we expect a continuation of the
                // multi-octet sequence
                if (0x80 == (0xC0 & ($in))) {
                    // Legal continuation.
                    $shift = ($mState - 1) * 6;
                    $tmp = $in;
                    $tmp = ($tmp & 0x0000003F) << $shift;
                    $mUcs4 |= $tmp;
                    
                    if (0 == --$mState) {
                        // End of the multi-octet sequence. mUcs4 now contains
                        // the final Unicode codepoint to be output
                        
                        // Check for illegal sequences and codepoints.
                        
                        // From Unicode 3.1, non-shortest form is illegal
                        if (((2 == $mBytes) && ($mUcs4 < 0x0080)) ||
                            ((3 == $mBytes) && ($mUcs4 < 0x0800)) ||
                            ((4 == $mBytes) && ($mUcs4 < 0x10000)) ||
                            (4 < $mBytes) ||
                            // From Unicode 3.2, surrogate characters = illegal
                            (($mUcs4 & 0xFFFFF800) == 0xD800) ||
                            // Codepoints outside the Unicode range are illegal
                            ($mUcs4 > 0x10FFFF)
                        ) {
                            
                        } elseif (0xFEFF != $mUcs4 && // omit BOM
                            // check for valid Char unicode codepoints
                            (
                                0x9 == $mUcs4 ||
                                0xA == $mUcs4 ||
                                0xD == $mUcs4 ||
                                (0x20 <= $mUcs4 && 0x7E >= $mUcs4) ||
                                // 7F-9F is not strictly prohibited by XML,
                                // but it is non-SGML, and thus we don't allow it
                                (0xA0 <= $mUcs4 && 0xD7FF >= $mUcs4) ||
                                (0x10000 <= $mUcs4 && 0x10FFFF >= $mUcs4)
                            )
                        ) {
                            $out .= $char;
                        }
                        // initialize UTF8 cache (reset)
                        $mState = 0;
                        $mUcs4  = 0;
                        $mBytes = 1;
                        $char = '';
                    }
                } else {
                    // ((0xC0 & (*in) != 0x80) && (mState != 0))
                    // Incomplete multi-octet sequence.
                    // used to result in complete fail, but we'll reset
                    $mState = 0;
                    $mUcs4  = 0;
                    $mBytes = 1;
                    $char ='';
                }
            }
        }
        return $out;
    }
    
    /**
     * Translates a Unicode codepoint into its corresponding UTF-8 character.
     * @note Based on Feyd's function at
     *       <http://forums.devnetwork.net/viewtopic.php?p=191404#191404>,
     *       which is in public domain.
     * @note While we're going to do code point parsing anyway, a good
     *       optimization would be to refuse to translate code points that
     *       are non-SGML characters.  However, this could lead to duplication.
     * @note This is very similar to the unichr function in
     *       maintenance/generate-entity-file.php (although this is superior,
     *       due to its sanity checks).
     */
    
    // +----------+----------+----------+----------+
    // | 33222222 | 22221111 | 111111   |          |
    // | 10987654 | 32109876 | 54321098 | 76543210 | bit
    // +----------+----------+----------+----------+
    // |          |          |          | 0xxxxxxx | 1 byte 0x00000000..0x0000007F
    // |          |          | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF
    // |          | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF
    // | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF
    // +----------+----------+----------+----------+
    // | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF)
    // | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes
    // +----------+----------+----------+----------+ 
    
    public static function unichr($code) {
        if($code > 1114111 or $code < 0 or
          ($code >= 55296 and $code <= 57343) ) {
            // bits are set outside the "valid" range as defined
            // by UNICODE 4.1.0 
            return '';
        }
        
        $x = $y = $z = $w = 0; 
        if ($code < 128) {
            // regular ASCII character
            $x = $code;
        } else {
            // set up bits for UTF-8
            $x = ($code & 63) | 128;
            if ($code < 2048) {
                $y = (($code & 2047) >> 6) | 192;
            } else {
                $y = (($code & 4032) >> 6) | 128;
                if($code < 65536) {
                    $z = (($code >> 12) & 15) | 224;
                } else {
                    $z = (($code >> 12) & 63) | 128;
                    $w = (($code >> 18) & 7)  | 240;
                }
            } 
        }
        // set up the actual character
        $ret = '';
        if($w) $ret .= chr($w);
        if($z) $ret .= chr($z);
        if($y) $ret .= chr($y);
        $ret .= chr($x); 
        
        return $ret;
    }
    
    /**
     * Converts a string to UTF-8 based on configuration.
     */
    public static function convertToUTF8($str, $config, $context) {
        $encoding = $config->get('Core', 'Encoding');
        if ($encoding === 'utf-8') return $str;
        static $iconv = null;
        if ($iconv === null) $iconv = function_exists('iconv');
        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
        if ($iconv && !$config->get('Test', 'ForceNoIconv')) {
            $str = iconv($encoding, 'utf-8//IGNORE', $str);
            // If the string is bjorked by Shift_JIS or a similar encoding
            // that doesn't support all of ASCII, convert the naughty
            // characters to their true byte-wise ASCII/UTF-8 equivalents.
            $str = strtr($str, HTMLPurifier_Encoder::testEncodingSupportsASCII($encoding));
            restore_error_handler();
            return $str;
        } elseif ($encoding === 'iso-8859-1') {
            $str = utf8_encode($str);
            restore_error_handler();
            return $str;
        }
        trigger_error('Encoding not supported', E_USER_ERROR);
    }
    
    /**
     * Converts a string from UTF-8 based on configuration.
     * @note Currently, this is a lossy conversion, with unexpressable
     *       characters being omitted.
     */
    public static function convertFromUTF8($str, $config, $context) {
        $encoding = $config->get('Core', 'Encoding');
        if ($encoding === 'utf-8') return $str;
        static $iconv = null;
        if ($iconv === null) $iconv = function_exists('iconv');
        if ($escape = $config->get('Core', 'EscapeNonASCIICharacters')) {
            $str = HTMLPurifier_Encoder::convertToASCIIDumbLossless($str);
        }
        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
        if ($iconv && !$config->get('Test', 'ForceNoIconv')) {
            // Undo our previous fix in convertToUTF8, otherwise iconv will barf
            $ascii_fix = HTMLPurifier_Encoder::testEncodingSupportsASCII($encoding);
            if (!$escape && !empty($ascii_fix)) {
                $clear_fix = array();
                foreach ($ascii_fix as $utf8 => $native) $clear_fix[$utf8] = '';
                $str = strtr($str, $clear_fix);
            }
            $str = strtr($str, array_flip($ascii_fix));
            // Normal stuff
            $str = iconv('utf-8', $encoding . '//IGNORE', $str);
            restore_error_handler();
            return $str;
        } elseif ($encoding === 'iso-8859-1') {
            $str = utf8_decode($str);
            restore_error_handler();
            return $str;
        }
        trigger_error('Encoding not supported', E_USER_ERROR);
    }
    
    /**
     * Lossless (character-wise) conversion of HTML to ASCII
     * @param $str UTF-8 string to be converted to ASCII
     * @returns ASCII encoded string with non-ASCII character entity-ized
     * @warning Adapted from MediaWiki, claiming fair use: this is a common
     *       algorithm. If you disagree with this license fudgery,
     *       implement it yourself.
     * @note Uses decimal numeric entities since they are best supported.
     * @note This is a DUMB function: it has no concept of keeping
     *       character entities that the projected character encoding
     *       can allow. We could possibly implement a smart version
     *       but that would require it to also know which Unicode
     *       codepoints the charset supported (not an easy task).
     * @note Sort of with cleanUTF8() but it assumes that $str is
     *       well-formed UTF-8
     */
    public static function convertToASCIIDumbLossless($str) {
        $bytesleft = 0;
        $result = '';
        $working = 0;
        $len = strlen($str);
        for( $i = 0; $i < $len; $i++ ) {
            $bytevalue = ord( $str[$i] );
            if( $bytevalue <= 0x7F ) { //0xxx xxxx
                $result .= chr( $bytevalue );
                $bytesleft = 0;
            } elseif( $bytevalue <= 0xBF ) { //10xx xxxx
                $working = $working << 6;
                $working += ($bytevalue & 0x3F);
                $bytesleft--;
                if( $bytesleft <= 0 ) {
                    $result .= "&#" . $working . ";";
                }
            } elseif( $bytevalue <= 0xDF ) { //110x xxxx
                $working = $bytevalue & 0x1F;
                $bytesleft = 1;
            } elseif( $bytevalue <= 0xEF ) { //1110 xxxx
                $working = $bytevalue & 0x0F;
                $bytesleft = 2;
            } else { //1111 0xxx
                $working = $bytevalue & 0x07;
                $bytesleft = 3;
            }
        }
        return $result;
    }
    
    /**
     * This expensive function tests whether or not a given character
     * encoding supports ASCII. 7/8-bit encodings like Shift_JIS will
     * fail this test, and require special processing. Variable width
     * encodings shouldn't ever fail.
     * 
     * @param string $encoding Encoding name to test, as per iconv format
     * @param bool $bypass Whether or not to bypass the precompiled arrays.
     * @return Array of UTF-8 characters to their corresponding ASCII,
     *      which can be used to "undo" any overzealous iconv action.
     */
    public static function testEncodingSupportsASCII($encoding, $bypass = false) {
        static $encodings = array();
        if (!$bypass) {
            if (isset($encodings[$encoding])) return $encodings[$encoding];
            $lenc = strtolower($encoding);
            switch ($lenc) {
                case 'shift_jis':
                    return array("\xC2\xA5" => '\\', "\xE2\x80\xBE" => '~');
                case 'johab':
                    return array("\xE2\x82\xA9" => '\\');
            }
            if (strpos($lenc, 'iso-8859-') === 0) return array();
        }
        $ret = array();
        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
        if (iconv('UTF-8', $encoding, 'a') === false) return false;
        for ($i = 0x20; $i <= 0x7E; $i++) { // all printable ASCII chars
            $c = chr($i);
            if (iconv('UTF-8', "$encoding//IGNORE", $c) === '') {
                // Reverse engineer: what's the UTF-8 equiv of this byte
                // sequence? This assumes that there's no variable width
                // encoding that doesn't support ASCII.
                $ret[iconv($encoding, 'UTF-8//IGNORE', $c)] = $c;
            }
        }
        restore_error_handler();
        $encodings[$encoding] = $ret;
        return $ret;
    }
    
    
}




/**
 * Object that provides entity lookup table from entity name to character
 */
class HTMLPurifier_EntityLookup {
    
    /**
     * Assoc array of entity name to character represented.
     */
    public $table;
    
    /**
     * Sets up the entity lookup table from the serialized file contents.
     * @note The serialized contents are versioned, but were generated
     *       using the maintenance script generate_entity_file.php
     * @warning This is not in constructor to help enforce the Singleton
     */
    public function setup($file = false) {
        if (!$file) {
            $file = HTMLPURIFIER_PREFIX . '/HTMLPurifier/EntityLookup/entities.ser';
        }
        $this->table = unserialize(file_get_contents($file));
    }
    
    /**
     * Retrieves sole instance of the object.
     * @param Optional prototype of custom lookup table to overload with.
     */
    public static function instance($prototype = false) {
        // no references, since PHP doesn't copy unless modified
        static $instance = null;
        if ($prototype) {
            $instance = $prototype;
        } elseif (!$instance) {
            $instance = new HTMLPurifier_EntityLookup();
            $instance->setup();
        }
        return $instance;
    }
    
}




// 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;
        }
    }
    
}




/**
 * Error collection class that enables HTML Purifier to report HTML
 * problems back to the user
 */
class HTMLPurifier_ErrorCollector
{
    
    protected $errors = array();
    protected $locale;
    protected $generator;
    protected $context;
    
    public function __construct($context) {
        $this->locale    =& $context->get('Locale');
        $this->generator =& $context->get('Generator');
        $this->context   = $context;
    }
    
    /**
     * Sends an error message to the collector for later use
     * @param $line Integer line number, or HTMLPurifier_Token that caused error
     * @param $severity int Error severity, PHP error style (don't use E_USER_)
     * @param $msg string Error message text
     */
    public function send($severity, $msg) {
        
        $args = array();
        if (func_num_args() > 2) {
            $args = func_get_args();
            array_shift($args);
            unset($args[0]);
        }
        
        $token = $this->context->get('CurrentToken', true);
        $line  = $token ? $token->line : $this->context->get('CurrentLine', true);
        $attr  = $this->context->get('CurrentAttr', true);
        
        // perform special substitutions, also add custom parameters
        $subst = array();
        if (!is_null($token)) {
            $args['CurrentToken'] = $token;
        }
        if (!is_null($attr)) {
            $subst['$CurrentAttr.Name'] = $attr;
            if (isset($token->attr[$attr])) $subst['$CurrentAttr.Value'] = $token->attr[$attr];
        }
        
        if (empty($args)) {
            $msg = $this->locale->getMessage($msg);
        } else {
            $msg = $this->locale->formatMessage($msg, $args);
        }
        
        if (!empty($subst)) $msg = strtr($msg, $subst);
        
        $this->errors[] = array($line, $severity, $msg);
    }
    
    /**
     * Retrieves raw error data for custom formatter to use
     * @param List of arrays in format of array(Error message text,
     *        token that caused error, tokens surrounding token)
     */
    public function getRaw() {
        return $this->errors;
    }
    
    /**
     * Default HTML formatting implementation for error messages
     * @param $config Configuration array, vital for HTML output nature
     */
    public function getHTMLFormatted($config) {
        $ret = array();
        
        $errors = $this->errors;
        
        // sort error array by line
        // line numbers are enabled if they aren't explicitly disabled
        if ($config->get('Core', 'MaintainLineNumbers') !== false) {
            $has_line       = array();
            $lines          = array();
            $original_order = array();
            foreach ($errors as $i => $error) {
                $has_line[] = (int) (bool) $error[0];
                $lines[] = $error[0];
                $original_order[] = $i;
            }
            array_multisort($has_line, SORT_DESC, $lines, SORT_ASC, $original_order, SORT_ASC, $errors);
        }
        
        foreach ($errors as $error) {
            list($line, $severity, $msg) = $error;
            $string = '';
            $string .= '<strong>' . $this->locale->getErrorName($severity) . '</strong>: ';
            $string .= $this->generator->escape($msg); 
            if ($line) {
                // have javascript link generation that causes 
                // textarea to skip to the specified line
                $string .= $this->locale->formatMessage(
                    'ErrorCollector: At line', array('line' => $line));
            }
            $ret[] = $string;
        }
        
        if (empty($errors)) {
            return '<p>' . $this->locale->getMessage('ErrorCollector: No errors') . '</p>';
        } else {
            return '<ul><li>' . implode('</li><li>', $ret) . '</li></ul>';
        }
        
    }
    
}




/**
 * Global exception class for HTML Purifier; any exceptions we throw
 * are from here.
 */
class HTMLPurifier_Exception extends Exception
{
    
}




/**
 * Represents a pre or post processing filter on HTML Purifier's output
 * 
 * Sometimes, a little ad-hoc fixing of HTML has to be done before
 * it gets sent through HTML Purifier: you can use filters to acheive
 * this effect. For instance, YouTube videos can be preserved using
 * this manner. You could have used a decorator for this task, but
 * PHP's support for them is not terribly robust, so we're going
 * to just loop through the filters.
 * 
 * Filters should be exited first in, last out. If there are three filters,
 * named 1, 2 and 3, the order of execution should go 1->preFilter,
 * 2->preFilter, 3->preFilter, purify, 3->postFilter, 2->postFilter,
 * 1->postFilter.
 * 
 * @note Methods are not declared abstract as it is perfectly legitimate
 *       for an implementation not to want anything to happen on a step
 */

class HTMLPurifier_Filter
{
    
    /**
     * Name of the filter for identification purposes
     */
    public $name;
    
    /**
     * Pre-processor function, handles HTML before HTML Purifier 
     */
    public function preFilter($html, $config, $context) {
        return $html;
    }
    
    /**
     * Post-processor function, handles HTML after HTML Purifier
     */
    public function postFilter($html, $config, $context) {
        return $html;
    }
    
}




/**
 * Generates HTML from tokens.
 * @todo Refactor interface so that configuration/context is determined
 *       upon instantiation, no need for messy generateFromTokens() calls
 * @todo Make some of the more internal functions protected, and have
 *       unit tests work around that
 */
class HTMLPurifier_Generator
{
    
    /**
     * Whether or not generator should produce XML output
     */
    private $_xhtml = true;
    
    /**
     * :HACK: Whether or not generator should comment the insides of <script> tags
     */
    private $_scriptFix = false;
    
    /**
     * Cache of HTMLDefinition during HTML output