code:
<?php

/**
 * Defines common attribute collections that modules reference
 */

class HTMLPurifier_AttrCollections
{

    /**
     * Associative array of attribute collections, indexed by name.
     * @type array
     */
    public $info = array();

    /**
     * Performs all expansions on internal data for use by other inclusions
     * It also collects all attribute collection extensions from
     * modules
     * @param HTMLPurifier_AttrTypes $attr_types HTMLPurifier_AttrTypes instance
     * @param HTMLPurifier_HTMLModule[] $modules Hash array of HTMLPurifier_HTMLModule members
     */
    public function __construct($attr_types, $modules)
    {
        $this->doConstruct($attr_types, $modules);
    }

    public function doConstruct($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 array &$attr Reference to attribute array
     */
    public function performInclusions(&$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 array &$attr Reference to attribute array
     * @param HTMLPurifier_AttrTypes $attr_types HTMLPurifier_AttrTypes instance
     */
    public function expandIdentifiers(&$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]);
            }
        }
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * 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.
     * @type bool
     */
    public $minimized = false;

    /**
     * Tells us whether or not an HTML attribute is required.
     * Has no meaning in other contexts
     * @type bool
     */
    public $required = false;

    /**
     * Validates and cleans passed string according to a definition.
     *
     * @param string $string String to be validated and cleaned.
     * @param HTMLPurifier_Config $config Mandatory HTMLPurifier_Config object.
     * @param HTMLPurifier_Context $context Mandatory HTMLPurifier_Context object.
     */
    abstract public function validate($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 String construction info
     * @return HTMLPurifier_AttrDef 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!
     * @param string $string a CSS colour definition
     * @return string
     */
    protected function mungeRgb($string)
    {
        $p = '\s*(\d+(\.\d+)?([%]?))\s*';

        if (preg_match('/(rgba|hsla)\(/', $string)) {
            return preg_replace('/(rgba|hsla)\('.$p.','.$p.','.$p.','.$p.'\)/', '\1(\2,\5,\8,\11)', $string);
        }

        return preg_replace('/(rgb|hsl)\('.$p.','.$p.','.$p.'\)/', '\1(\2,\5,\8)', $string);
    }

    /**
     * Parses a possibly escaped CSS string and returns the "pure"
     * version of it.
     */
    protected function expandCSSEscape($string)
    {
        // flexibly parse it
        $ret = '';
        for ($i = 0, $c = strlen($string); $i < $c; $i++) {
            if ($string[$i] === '\\') {
                $i++;
                if ($i >= $c) {
                    $ret .= '\\';
                    break;
                }
                if (ctype_xdigit($string[$i])) {
                    $code = $string[$i];
                    for ($a = 1, $i++; $i < $c && $a < 6; $i++, $a++) {
                        if (!ctype_xdigit($string[$i])) {
                            break;
                        }
                        $code .= $string[$i];
                    }
                    // We have to be extremely careful when adding
                    // new characters, to make sure we're not breaking
                    // the encoding.
                    $char = HTMLPurifier_Encoder::unichr(hexdec($code));
                    if (HTMLPurifier_Encoder::cleanUTF8($char) === '') {
                        continue;
                    }
                    $ret .= $char;
                    if ($i < $c && trim($string[$i]) !== '') {
                        $i--;
                    }
                    continue;
                }
                if ($string[$i] === "\n") {
                    continue;
                }
            }
            $ret .= $string[$i];
        }
        return $ret;
    }
}

// vim: et sw=4 sts=4

repo_name: andremichelle/gnu

license: mit


code:
<?php

/**
 * Validates the HTML attribute style, otherwise known as CSS.
 * @note We don't implement the whole CSS specification, so it might be
 *       difficult to reuse this component in the context of validating
 *       actual stylesheet declarations.
 * @note If we were really serious about validating the CSS, we would
 *       tokenize the styles and then parse the tokens. Obviously, we
 *       are not doing that. Doing that could seriously harm performance,
 *       but would make these components a lot more viable for a CSS
 *       filtering solution.
 */
class HTMLPurifier_AttrDef_CSS extends HTMLPurifier_AttrDef
{

    /**
     * @param string $css
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($css, $config, $context)
    {
        $css = $this->parseCDATA($css);

        $definition = $config->getCSSDefinition();
        $allow_duplicates = $config->get("CSS.AllowDuplicates");

        // According to the CSS2.1 spec, the places where a
        // non-delimiting semicolon can appear are in strings
        // escape sequences.   So here is some dumb hack to
        // handle quotes.
        $len = strlen($css);
        $accum = "";
        $declarations = array();
        $quoted = false;
        for ($i = 0; $i < $len; $i++) {
            $c = strcspn($css, ";'\"", $i);
            $accum .= substr($css, $i, $c);
            $i += $c;
            if ($i == $len) break;
            $d = $css[$i];
            if ($quoted) {
                $accum .= $d;
                if ($d == $quoted) {
                    $quoted = false;
                }
            } else {
                if ($d == ";") {
                    $declarations[] = $accum;
                    $accum = "";
                } else {
                    $accum .= $d;
                    $quoted = $d;
                }
            }
        }
        if ($accum != "") $declarations[] = $accum;

        $propvalues = array();
        $new_declarations = '';

        /**
         * Name of the current CSS property being validated.
         */
        $property = false;
        $context->register('CurrentCSSProperty', $property);

        foreach ($declarations as $declaration) {
            if (!$declaration) {
                continue;
            }
            if (!strpos($declaration, ':')) {
                continue;
            }
            list($property, $value) = explode(':', $declaration, 2);
            $property = trim($property);
            $value = trim($value);
            $ok = false;
            do {
                if (isset($definition->info[$property])) {
                    $ok = true;
                    break;
                }
                if (ctype_lower($property)) {
                    break;
                }
                $property = strtolower($property);
                if (isset($definition->info[$property])) {
                    $ok = true;
                    break;
                }
            } while (0);
            if (!$ok) {
                continue;
            }
            // inefficient call, since the validator will do this again
            if (strtolower(trim($value)) !== 'inherit') {
                // inherit works for everything (but only on the base property)
                $result = $definition->info[$property]->validate(
                    $value,
                    $config,
                    $context
                );
            } else {
                $result = 'inherit';
            }
            if ($result === false) {
                continue;
            }
            if ($allow_duplicates) {
                $new_declarations .= "$property:$result;";
            } else {
                $propvalues[$property] = $result;
            }
        }

        $context->destroy('CurrentCSSProperty');

        // procedure does not write the new CSS simultaneously, so it's
        // slightly inefficient, but it's the only way of getting rid of
        // duplicates. Perhaps config to optimize it, but not now.

        foreach ($propvalues as $prop => $value) {
            $new_declarations .= "$prop:$value;";
        }

        return $new_declarations ? $new_declarations : false;

    }

}

// vim: et sw=4 sts=4


code:
<?php

class HTMLPurifier_AttrDef_CSS_AlphaValue extends HTMLPurifier_AttrDef_CSS_Number
{

    public function __construct()
    {
        parent::__construct(false); // opacity is non-negative, but we will clamp it
    }

    /**
     * @param string $number
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return string
     */
    public function validate($number, $config, $context)
    {
        $result = parent::validate($number, $config, $context);
        if ($result === false) {
            return $result;
        }
        $float = (float)$result;
        if ($float < 0.0) {
            $result = '0';
        }
        if ($float > 1.0) {
            $result = '1';
        }
        return $result;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates shorthand CSS property background.
 * @warning Does not support url tokens that have internal spaces.
 */
class HTMLPurifier_AttrDef_CSS_Background extends HTMLPurifier_AttrDef
{

    /**
     * Local copy of component validators.
     * @type HTMLPurifier_AttrDef[]
     * @note See HTMLPurifier_AttrDef_Font::$info for a similar impl.
     */
    protected $info;

    /**
     * @param HTMLPurifier_Config $config
     */
    public function __construct($config)
    {
        $def = $config->getCSSDefinition();
        $this->info['background-color'] = $def->info['background-color'];
        $this->info['background-image'] = $def->info['background-image'];
        $this->info['background-repeat'] = $def->info['background-repeat'];
        $this->info['background-attachment'] = $def->info['background-attachment'];
        $this->info['background-position'] = $def->info['background-position'];
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        // regular pre-processing
        $string = $this->parseCDATA($string);
        if ($string === '') {
            return false;
        }

        // munge rgb() decl if necessary
        $string = $this->mungeRgb($string);

        // assumes URI doesn't have spaces in it
        $bits = explode(' ', $string); // bits to process

        $caught = array();
        $caught['color'] = false;
        $caught['image'] = false;
        $caught['repeat'] = false;
        $caught['attachment'] = false;
        $caught['position'] = false;

        $i = 0; // number of catches

        foreach ($bits as $bit) {
            if ($bit === '') {
                continue;
            }
            foreach ($caught as $key => $status) {
                if ($key != 'position') {
                    if ($status !== false) {
                        continue;
                    }
                    $r = $this->info['background-' . $key]->validate($bit, $config, $context);
                } else {
                    $r = $bit;
                }
                if ($r === false) {
                    continue;
                }
                if ($key == 'position') {
                    if ($caught[$key] === false) {
                        $caught[$key] = '';
                    }
                    $caught[$key] .= $r . ' ';
                } else {
                    $caught[$key] = $r;
                }
                $i++;
                break;
            }
        }

        if (!$i) {
            return false;
        }
        if ($caught['position'] !== false) {
            $caught['position'] = $this->info['background-position']->
                validate($caught['position'], $config, $context);
        }

        $ret = array();
        foreach ($caught as $value) {
            if ($value === false) {
                continue;
            }
            $ret[] = $value;
        }

        if (empty($ret)) {
            return false;
        }
        return implode(' ', $ret);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/* W3C says:
    [ // adjective and number must be in correct order, even if
      // you could switch them without introducing ambiguity.
      // some browsers support that syntax
        [
            <percentage> | <length> | left | center | right
        ]
        [
            <percentage> | <length> | top | center | bottom
        ]?
    ] |
    [ // this signifies that the vertical and horizontal adjectives
      // can be arbitrarily ordered, however, there can only be two,
      // one of each, or none at all
        [
            left | center | right
        ] ||
        [
            top | center | bottom
        ]
    ]
    top, left = 0%
    center, (none) = 50%
    bottom, right = 100%
*/

/* QuirksMode says:
    keyword + length/percentage must be ordered correctly, as per W3C

    Internet Explorer and Opera, however, support arbitrary ordering. We
    should fix it up.

    Minor issue though, not strictly necessary.
*/

// control freaks may appreciate the ability to convert these to
// percentages or something, but it's not necessary

/**
 * Validates the value of background-position.
 */
class HTMLPurifier_AttrDef_CSS_BackgroundPosition extends HTMLPurifier_AttrDef
{

    /**
     * @type HTMLPurifier_AttrDef_CSS_Length
     */
    protected $length;

    /**
     * @type HTMLPurifier_AttrDef_CSS_Percentage
     */
    protected $percentage;

    public function __construct()
    {
        $this->length = new HTMLPurifier_AttrDef_CSS_Length();
        $this->percentage = new HTMLPurifier_AttrDef_CSS_Percentage();
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = $this->parseCDATA($string);
        $bits = explode(' ', $string);

        $keywords = array();
        $keywords['h'] = false; // left, right
        $keywords['v'] = false; // top, bottom
        $keywords['ch'] = false; // center (first word)
        $keywords['cv'] = false; // center (second word)
        $measures = array();

        $i = 0;

        $lookup = array(
            'top' => 'v',
            'bottom' => 'v',
            'left' => 'h',
            'right' => 'h',
            'center' => 'c'
        );

        foreach ($bits as $bit) {
            if ($bit === '') {
                continue;
            }

            // test for keyword
            $lbit = ctype_lower($bit) ? $bit : strtolower($bit);
            if (isset($lookup[$lbit])) {
                $status = $lookup[$lbit];
                if ($status == 'c') {
                    if ($i == 0) {
                        $status = 'ch';
                    } else {
                        $status = 'cv';
                    }
                }
                $keywords[$status] = $lbit;
                $i++;
            }

            // test for length
            $r = $this->length->validate($bit, $config, $context);
            if ($r !== false) {
                $measures[] = $r;
                $i++;
            }

            // test for percentage
            $r = $this->percentage->validate($bit, $config, $context);
            if ($r !== false) {
                $measures[] = $r;
                $i++;
            }
        }

        if (!$i) {
            return false;
        } // no valid values were caught

        $ret = array();

        // first keyword
        if ($keywords['h']) {
            $ret[] = $keywords['h'];
        } elseif ($keywords['ch']) {
            $ret[] = $keywords['ch'];
            $keywords['cv'] = false; // prevent re-use: center = center center
        } elseif (count($measures)) {
            $ret[] = array_shift($measures);
        }

        if ($keywords['v']) {
            $ret[] = $keywords['v'];
        } elseif ($keywords['cv']) {
            $ret[] = $keywords['cv'];
        } elseif (count($measures)) {
            $ret[] = array_shift($measures);
        }

        if (empty($ret)) {
            return false;
        }
        return implode(' ', $ret);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates the border property as defined by CSS.
 */
class HTMLPurifier_AttrDef_CSS_Border extends HTMLPurifier_AttrDef
{

    /**
     * Local copy of properties this property is shorthand for.
     * @type HTMLPurifier_AttrDef[]
     */
    protected $info = array();

    /**
     * @param HTMLPurifier_Config $config
     */
    public function __construct($config)
    {
        $def = $config->getCSSDefinition();
        $this->info['border-width'] = $def->info['border-width'];
        $this->info['border-style'] = $def->info['border-style'];
        $this->info['border-top-color'] = $def->info['border-top-color'];
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = $this->parseCDATA($string);
        $string = $this->mungeRgb($string);
        $bits = explode(' ', $string);
        $done = array(); // segments we've finished
        $ret = ''; // return value
        foreach ($bits as $bit) {
            foreach ($this->info as $propname => $validator) {
                if (isset($done[$propname])) {
                    continue;
                }
                $r = $validator->validate($bit, $config, $context);
                if ($r !== false) {
                    $ret .= $r . ' ';
                    $done[$propname] = true;
                    break;
                }
            }
        }
        return rtrim($ret);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates Color as defined by CSS.
 */
class HTMLPurifier_AttrDef_CSS_Color extends HTMLPurifier_AttrDef
{

    /**
     * @type HTMLPurifier_AttrDef_CSS_AlphaValue
     */
    protected $alpha;

    public function __construct()
    {
        $this->alpha = new HTMLPurifier_AttrDef_CSS_AlphaValue();
    }

    /**
     * @param string $color
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($color, $config, $context)
    {
        static $colors = null;
        if ($colors === null) {
            $colors = $config->get('Core.ColorKeywords');
        }

        $color = trim($color);
        if ($color === '') {
            return false;
        }

        $lower = strtolower($color);
        if (isset($colors[$lower])) {
            return $colors[$lower];
        }

        if (preg_match('#(rgb|rgba|hsl|hsla)\(#', $color, $matches) === 1) {
            $length = strlen($color);
            if (strpos($color, ')') !== $length - 1) {
                return false;
            }

            // get used function : rgb, rgba, hsl or hsla
            $function = $matches[1];

            $parameters_size = 3;
            $alpha_channel = false;
            if (substr($function, -1) === 'a') {
                $parameters_size = 4;
                $alpha_channel = true;
            }

            /*
             * Allowed types for values :
             * parameter_position => [type => max_value]
             */
            $allowed_types = array(
                1 => array('percentage' => 100, 'integer' => 255),
                2 => array('percentage' => 100, 'integer' => 255),
                3 => array('percentage' => 100, 'integer' => 255),
            );
            $allow_different_types = false;

            if (strpos($function, 'hsl') !== false) {
                $allowed_types = array(
                    1 => array('integer' => 360),
                    2 => array('percentage' => 100),
                    3 => array('percentage' => 100),
                );
                $allow_different_types = true;
            }

            $values = trim(str_replace($function, '', $color), ' ()');

            $parts = explode(',', $values);
            if (count($parts) !== $parameters_size) {
                return false;
            }

            $type = false;
            $new_parts = array();
            $i = 0;

            foreach ($parts as $part) {
                $i++;
                $part = trim($part);

                if ($part === '') {
                    return false;
                }

                // different check for alpha channel
                if ($alpha_channel === true && $i === count($parts)) {
                    $result = $this->alpha->validate($part, $config, $context);

                    if ($result === false) {
                        return false;
                    }

                    $new_parts[] = (string)$result;
                    continue;
                }

                if (substr($part, -1) === '%') {
                    $current_type = 'percentage';
                } else {
                    $current_type = 'integer';
                }

                if (!array_key_exists($current_type, $allowed_types[$i])) {
                    return false;
                }

                if (!$type) {
                    $type = $current_type;
                }

                if ($allow_different_types === false && $type != $current_type) {
                    return false;
                }

                $max_value = $allowed_types[$i][$current_type];

                if ($current_type == 'integer') {
                    // Return value between range 0 -> $max_value
                    $new_parts[] = (int)max(min($part, $max_value), 0);
                } elseif ($current_type == 'percentage') {
                    $new_parts[] = (float)max(min(rtrim($part, '%'), $max_value), 0) . '%';
                }
            }

            $new_values = implode(',', $new_parts);

            $color = $function . '(' . $new_values . ')';
        } else {
            // hexadecimal handling
            if ($color[0] === '#') {
                $hex = substr($color, 1);
            } else {
                $hex = $color;
                $color = '#' . $color;
            }
            $length = strlen($hex);
            if ($length !== 3 && $length !== 6) {
                return false;
            }
            if (!ctype_xdigit($hex)) {
                return false;
            }
        }
        return $color;
    }

}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Allows multiple validators to attempt to validate attribute.
 *
 * Composite is just what it sounds like: a composite of many validators.
 * This means that multiple HTMLPurifier_AttrDef objects will have a whack
 * at the string.  If one of them passes, that's what is returned.  This is
 * especially useful for CSS values, which often are a choice between
 * an enumerated set of predefined values or a flexible data type.
 */
class HTMLPurifier_AttrDef_CSS_Composite extends HTMLPurifier_AttrDef
{

    /**
     * List of objects that may process strings.
     * @type HTMLPurifier_AttrDef[]
     * @todo Make protected
     */
    public $defs;

    /**
     * @param HTMLPurifier_AttrDef[] $defs List of HTMLPurifier_AttrDef objects
     */
    public function __construct($defs)
    {
        $this->defs = $defs;
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        foreach ($this->defs as $i => $def) {
            $result = $this->defs[$i]->validate($string, $config, $context);
            if ($result !== false) {
                return $result;
            }
        }
        return false;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Decorator which enables CSS properties to be disabled for specific elements.
 */
class HTMLPurifier_AttrDef_CSS_DenyElementDecorator extends HTMLPurifier_AttrDef
{
    /**
     * @type HTMLPurifier_AttrDef
     */
    public $def;
    /**
     * @type string
     */
    public $element;

    /**
     * @param HTMLPurifier_AttrDef $def Definition to wrap
     * @param string $element Element to deny
     */
    public function __construct($def, $element)
    {
        $this->def = $def;
        $this->element = $element;
    }

    /**
     * Checks if CurrentToken is set and equal to $this->element
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $token = $context->get('CurrentToken', true);
        if ($token && $token->name == $this->element) {
            return false;
        }
        return $this->def->validate($string, $config, $context);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Microsoft's proprietary filter: CSS property
 * @note Currently supports the alpha filter. In the future, this will
 *       probably need an extensible framework
 */
class HTMLPurifier_AttrDef_CSS_Filter extends HTMLPurifier_AttrDef
{
    /**
     * @type HTMLPurifier_AttrDef_Integer
     */
    protected $intValidator;

    public function __construct()
    {
        $this->intValidator = new HTMLPurifier_AttrDef_Integer();
    }

    /**
     * @param string $value
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($value, $config, $context)
    {
        $value = $this->parseCDATA($value);
        if ($value === 'none') {
            return $value;
        }
        // if we looped this we could support multiple filters
        $function_length = strcspn($value, '(');
        $function = trim(substr($value, 0, $function_length));
        if ($function !== 'alpha' &&
            $function !== 'Alpha' &&
            $function !== 'progid:DXImageTransform.Microsoft.Alpha'
        ) {
            return false;
        }
        $cursor = $function_length + 1;
        $parameters_length = strcspn($value, ')', $cursor);
        $parameters = substr($value, $cursor, $parameters_length);
        $params = explode(',', $parameters);
        $ret_params = array();
        $lookup = array();
        foreach ($params as $param) {
            list($key, $value) = explode('=', $param);
            $key = trim($key);
            $value = trim($value);
            if (isset($lookup[$key])) {
                continue;
            }
            if ($key !== 'opacity') {
                continue;
            }
            $value = $this->intValidator->validate($value, $config, $context);
            if ($value === false) {
                continue;
            }
            $int = (int)$value;
            if ($int > 100) {
                $value = '100';
            }
            if ($int < 0) {
                $value = '0';
            }
            $ret_params[] = "$key=$value";
            $lookup[$key] = true;
        }
        $ret_parameters = implode(',', $ret_params);
        $ret_function = "$function($ret_parameters)";
        return $ret_function;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates shorthand CSS property font.
 */
class HTMLPurifier_AttrDef_CSS_Font extends HTMLPurifier_AttrDef
{

    /**
     * Local copy of validators
     * @type HTMLPurifier_AttrDef[]
     * @note If we moved specific CSS property definitions to their own
     *       classes instead of having them be assembled at run time by
     *       CSSDefinition, this wouldn't be necessary.  We'd instantiate
     *       our own copies.
     */
    protected $info = array();

    /**
     * @param HTMLPurifier_Config $config
     */
    public function __construct($config)
    {
        $def = $config->getCSSDefinition();
        $this->info['font-style'] = $def->info['font-style'];
        $this->info['font-variant'] = $def->info['font-variant'];
        $this->info['font-weight'] = $def->info['font-weight'];
        $this->info['font-size'] = $def->info['font-size'];
        $this->info['line-height'] = $def->info['line-height'];
        $this->info['font-family'] = $def->info['font-family'];
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        static $system_fonts = array(
            'caption' => true,
            'icon' => true,
            'menu' => true,
            'message-box' => true,
            'small-caption' => true,
            'status-bar' => true
        );

        // regular pre-processing
        $string = $this->parseCDATA($string);
        if ($string === '') {
            return false;
        }

        // check if it's one of the keywords
        $lowercase_string = strtolower($string);
        if (isset($system_fonts[$lowercase_string])) {
            return $lowercase_string;
        }

        $bits = explode(' ', $string); // bits to process
        $stage = 0; // this indicates what we're looking for
        $caught = array(); // which stage 0 properties have we caught?
        $stage_1 = array('font-style', 'font-variant', 'font-weight');
        $final = ''; // output

        for ($i = 0, $size = count($bits); $i < $size; $i++) {
            if ($bits[$i] === '') {
                continue;
            }
            switch ($stage) {
                case 0: // attempting to catch font-style, font-variant or font-weight
                    foreach ($stage_1 as $validator_name) {
                        if (isset($caught[$validator_name])) {
                            continue;
                        }
                        $r = $this->info[$validator_name]->validate(
                            $bits[$i],
                            $config,
                            $context
                        );
                        if ($r !== false) {
                            $final .= $r . ' ';
                            $caught[$validator_name] = true;
                            break;
                        }
                    }
                    // all three caught, continue on
                    if (count($caught) >= 3) {
                        $stage = 1;
                    }
                    if ($r !== false) {
                        break;
                    }
                case 1: // attempting to catch font-size and perhaps line-height
                    $found_slash = false;
                    if (strpos($bits[$i], '/') !== false) {
                        list($font_size, $line_height) =
                            explode('/', $bits[$i]);
                        if ($line_height === '') {
                            // ooh, there's a space after the slash!
                            $line_height = false;
                            $found_slash = true;
                        }
                    } else {
                        $font_size = $bits[$i];
                        $line_height = false;
                    }
                    $r = $this->info['font-size']->validate(
                        $font_size,
                        $config,
                        $context
                    );
                    if ($r !== false) {
                        $final .= $r;
                        // attempt to catch line-height
                        if ($line_height === false) {
                            // we need to scroll forward
                            for ($j = $i + 1; $j < $size; $j++) {
                                if ($bits[$j] === '') {
                                    continue;
                                }
                                if ($bits[$j] === '/') {
                                    if ($found_slash) {
                                        return false;
                                    } else {
                                        $found_slash = true;
                                        continue;
                                    }
                                }
                                $line_height = $bits[$j];
                                break;
                            }
                        } else {
                            // slash already found
                            $found_slash = true;
                            $j = $i;
                        }
                        if ($found_slash) {
                            $i = $j;
                            $r = $this->info['line-height']->validate(
                                $line_height,
                                $config,
                                $context
                            );
                            if ($r !== false) {
                                $final .= '/' . $r;
                            }
                        }
                        $final .= ' ';
                        $stage = 2;
                        break;
                    }
                    return false;
                case 2: // attempting to catch font-family
                    $font_family =
                        implode(' ', array_slice($bits, $i, $size - $i));
                    $r = $this->info['font-family']->validate(
                        $font_family,
                        $config,
                        $context
                    );
                    if ($r !== false) {
                        $final .= $r . ' ';
                        // processing completed successfully
                        return rtrim($final);
                    }
                    return false;
            }
        }
        return false;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates a font family list according to CSS spec
 */
class HTMLPurifier_AttrDef_CSS_FontFamily extends HTMLPurifier_AttrDef
{

    protected $mask = null;

    public function __construct()
    {
        $this->mask = '_- ';
        for ($c = 'a'; $c <= 'z'; $c++) {
            $this->mask .= $c;
        }
        for ($c = 'A'; $c <= 'Z'; $c++) {
            $this->mask .= $c;
        }
        for ($c = '0'; $c <= '9'; $c++) {
            $this->mask .= $c;
        } // cast-y, but should be fine
        // special bytes used by UTF-8
        for ($i = 0x80; $i <= 0xFF; $i++) {
            // We don't bother excluding invalid bytes in this range,
            // because the our restriction of well-formed UTF-8 will
            // prevent these from ever occurring.
            $this->mask .= chr($i);
        }

        /*
            PHP's internal strcspn implementation is
            O(length of string * length of mask), making it inefficient
            for large masks.  However, it's still faster than
            preg_match 8)
          for (p = s1;;) {
            spanp = s2;
            do {
              if (*spanp == c || p == s1_end) {
                return p - s1;
              }
            } while (spanp++ < (s2_end - 1));
            c = *++p;
          }
         */
        // possible optimization: invert the mask.
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        static $generic_names = array(
            'serif' => true,
            'sans-serif' => true,
            'monospace' => true,
            'fantasy' => true,
            'cursive' => true
        );
        $allowed_fonts = $config->get('CSS.AllowedFonts');

        // assume that no font names contain commas in them
        $fonts = explode(',', $string);
        $final = '';
        foreach ($fonts as $font) {
            $font = trim($font);
            if ($font === '') {
                continue;
            }
            // match a generic name
            if (isset($generic_names[$font])) {
                if ($allowed_fonts === null || isset($allowed_fonts[$font])) {
                    $final .= $font . ', ';
                }
                continue;
            }
            // match a quoted name
            if ($font[0] === '"' || $font[0] === "'") {
                $length = strlen($font);
                if ($length <= 2) {
                    continue;
                }
                $quote = $font[0];
                if ($font[$length - 1] !== $quote) {
                    continue;
                }
                $font = substr($font, 1, $length - 2);
            }

            $font = $this->expandCSSEscape($font);

            // $font is a pure representation of the font name

            if ($allowed_fonts !== null && !isset($allowed_fonts[$font])) {
                continue;
            }

            if (ctype_alnum($font) && $font !== '') {
                // very simple font, allow it in unharmed
                $final .= $font . ', ';
                continue;
            }

            // bugger out on whitespace.  form feed (0C) really
            // shouldn't show up regardless
            $font = str_replace(array("\n", "\t", "\r", "\x0C"), ' ', $font);

            // Here, there are various classes of characters which need
            // to be treated differently:
            //  - Alphanumeric characters are essentially safe.  We
            //    handled these above.
            //  - Spaces require quoting, though most parsers will do
            //    the right thing if there aren't any characters that
            //    can be misinterpreted
            //  - Dashes rarely occur, but they fairly unproblematic
            //    for parsing/rendering purposes.
            //  The above characters cover the majority of Western font
            //  names.
            //  - Arbitrary Unicode characters not in ASCII.  Because
            //    most parsers give little thought to Unicode, treatment
            //    of these codepoints is basically uniform, even for
            //    punctuation-like codepoints.  These characters can
            //    show up in non-Western pages and are supported by most
            //    major browsers, for example: "ＭＳ 明朝" is a
            //    legitimate font-name
            //    <http://ja.wikipedia.org/wiki/MS_明朝>.  See
            //    the CSS3 spec for more examples:
            //    <http://www.w3.org/TR/2011/WD-css3-fonts-20110324/localizedfamilynames.png>
            //    You can see live samples of these on the Internet:
            //    <http://www.google.co.jp/search?q=font-family+ＭＳ+明朝|ゴシック>
            //    However, most of these fonts have ASCII equivalents:
            //    for example, 'MS Mincho', and it's considered
            //    professional to use ASCII font names instead of
            //    Unicode font names.  Thanks Takeshi Terada for
            //    providing this information.
            //  The following characters, to my knowledge, have not been
            //  used to name font names.
            //  - Single quote.  While theoretically you might find a
            //    font name that has a single quote in its name (serving
            //    as an apostrophe, e.g. Dave's Scribble), I haven't
            //    been able to find any actual examples of this.
            //    Internet Explorer's cssText translation (which I
            //    believe is invoked by innerHTML) normalizes any
            //    quoting to single quotes, and fails to escape single
            //    quotes.  (Note that this is not IE's behavior for all
            //    CSS properties, just some sort of special casing for
            //    font-family).  So a single quote *cannot* be used
            //    safely in the font-family context if there will be an
            //    innerHTML/cssText translation.  Note that Firefox 3.x
            //    does this too.
            //  - Double quote.  In IE, these get normalized to
            //    single-quotes, no matter what the encoding.  (Fun
            //    fact, in IE8, the 'content' CSS property gained
            //    support, where they special cased to preserve encoded
            //    double quotes, but still translate unadorned double
            //    quotes into single quotes.)  So, because their
            //    fixpoint behavior is identical to single quotes, they
            //    cannot be allowed either.  Firefox 3.x displays
            //    single-quote style behavior.
            //  - Backslashes are reduced by one (so \\ -> \) every
            //    iteration, so they cannot be used safely.  This shows
            //    up in IE7, IE8 and FF3
            //  - Semicolons, commas and backticks are handled properly.
            //  - The rest of the ASCII punctuation is handled properly.
            // We haven't checked what browsers do to unadorned
            // versions, but this is not important as long as the
            // browser doesn't /remove/ surrounding quotes (as IE does
            // for HTML).
            //
            // With these results in hand, we conclude that there are
            // various levels of safety:
            //  - Paranoid: alphanumeric, spaces and dashes(?)
            //  - International: Paranoid + non-ASCII Unicode
            //  - Edgy: Everything except quotes, backslashes
            //  - NoJS: Standards compliance, e.g. sod IE. Note that
            //    with some judicious character escaping (since certain
            //    types of escaping doesn't work) this is theoretically
            //    OK as long as innerHTML/cssText is not called.
            // We believe that international is a reasonable default
            // (that we will implement now), and once we do more
            // extensive research, we may feel comfortable with dropping
            // it down to edgy.

            // Edgy: alphanumeric, spaces, dashes, underscores and Unicode.  Use of
            // str(c)spn assumes that the string was already well formed
            // Unicode (which of course it is).
            if (strspn($font, $this->mask) !== strlen($font)) {
                continue;
            }

            // Historical:
            // In the absence of innerHTML/cssText, these ugly
            // transforms don't pose a security risk (as \\ and \"
            // might--these escapes are not supported by most browsers).
            // We could try to be clever and use single-quote wrapping
            // when there is a double quote present, but I have choosen
            // not to implement that.  (NOTE: you can reduce the amount
            // of escapes by one depending on what quoting style you use)
            // $font = str_replace('\\', '\\5C ', $font);
            // $font = str_replace('"',  '\\22 ', $font);
            // $font = str_replace("'",  '\\27 ', $font);

            // font possibly with spaces, requires quoting
            $final .= "'$font', ";
        }
        $final = rtrim($final, ', ');
        if ($final === '') {
            return false;
        }
        return $final;
    }

}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates based on {ident} CSS grammar production
 */
class HTMLPurifier_AttrDef_CSS_Ident extends HTMLPurifier_AttrDef
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = trim($string);

        // early abort: '' and '0' (strings that convert to false) are invalid
        if (!$string) {
            return false;
        }

        $pattern = '/^(-?[A-Za-z_][A-Za-z_\-0-9]*)$/';
        if (!preg_match($pattern, $string)) {
            return false;
        }
        return $string;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Decorator which enables !important to be used in CSS values.
 */
class HTMLPurifier_AttrDef_CSS_ImportantDecorator extends HTMLPurifier_AttrDef
{
    /**
     * @type HTMLPurifier_AttrDef
     */
    public $def;
    /**
     * @type bool
     */
    public $allow;

    /**
     * @param HTMLPurifier_AttrDef $def Definition to wrap
     * @param bool $allow Whether or not to allow !important
     */
    public function __construct($def, $allow = false)
    {
        $this->def = $def;
        $this->allow = $allow;
    }

    /**
     * Intercepts and removes !important if necessary
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        // test for ! and important tokens
        $string = trim($string);
        $is_important = false;
        // :TODO: optimization: test directly for !important and ! important
        if (strlen($string) >= 9 && substr($string, -9) === 'important') {
            $temp = rtrim(substr($string, 0, -9));
            // use a temp, because we might want to restore important
            if (strlen($temp) >= 1 && substr($temp, -1) === '!') {
                $string = rtrim(substr($temp, 0, -1));
                $is_important = true;
            }
        }
        $string = $this->def->validate($string, $config, $context);
        if ($this->allow && $is_important) {
            $string .= ' !important';
        }
        return $string;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Represents a Length as defined by CSS.
 */
class HTMLPurifier_AttrDef_CSS_Length extends HTMLPurifier_AttrDef
{

    /**
     * @type HTMLPurifier_Length|string
     */
    protected $min;

    /**
     * @type HTMLPurifier_Length|string
     */
    protected $max;

    /**
     * @param HTMLPurifier_Length|string $min Minimum length, or null for no bound. String is also acceptable.
     * @param HTMLPurifier_Length|string $max Maximum length, or null for no bound. String is also acceptable.
     */
    public function __construct($min = null, $max = null)
    {
        $this->min = $min !== null ? HTMLPurifier_Length::make($min) : null;
        $this->max = $max !== null ? HTMLPurifier_Length::make($max) : null;
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = $this->parseCDATA($string);

        // Optimizations
        if ($string === '') {
            return false;
        }
        if ($string === '0') {
            return '0';
        }
        if (strlen($string) === 1) {
            return false;
        }

        $length = HTMLPurifier_Length::make($string);
        if (!$length->isValid()) {
            return false;
        }

        if ($this->min) {
            $c = $length->compareTo($this->min);
            if ($c === false) {
                return false;
            }
            if ($c < 0) {
                return false;
            }
        }
        if ($this->max) {
            $c = $length->compareTo($this->max);
            if ($c === false) {
                return false;
            }
            if ($c > 0) {
                return false;
            }
        }
        return $length->toString();
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates shorthand CSS property list-style.
 * @warning Does not support url tokens that have internal spaces.
 */
class HTMLPurifier_AttrDef_CSS_ListStyle extends HTMLPurifier_AttrDef
{

    /**
     * Local copy of validators.
     * @type HTMLPurifier_AttrDef[]
     * @note See HTMLPurifier_AttrDef_CSS_Font::$info for a similar impl.
     */
    protected $info;

    /**
     * @param HTMLPurifier_Config $config
     */
    public function __construct($config)
    {
        $def = $config->getCSSDefinition();
        $this->info['list-style-type'] = $def->info['list-style-type'];
        $this->info['list-style-position'] = $def->info['list-style-position'];
        $this->info['list-style-image'] = $def->info['list-style-image'];
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        // regular pre-processing
        $string = $this->parseCDATA($string);
        if ($string === '') {
            return false;
        }

        // assumes URI doesn't have spaces in it
        $bits = explode(' ', strtolower($string)); // bits to process

        $caught = array();
        $caught['type'] = false;
        $caught['position'] = false;
        $caught['image'] = false;

        $i = 0; // number of catches
        $none = false;

        foreach ($bits as $bit) {
            if ($i >= 3) {
                return;
            } // optimization bit
            if ($bit === '') {
                continue;
            }
            foreach ($caught as $key => $status) {
                if ($status !== false) {
                    continue;
                }
                $r = $this->info['list-style-' . $key]->validate($bit, $config, $context);
                if ($r === false) {
                    continue;
                }
                if ($r === 'none') {
                    if ($none) {
                        continue;
                    } else {
                        $none = true;
                    }
                    if ($key == 'image') {
                        continue;
                    }
                }
                $caught[$key] = $r;
                $i++;
                break;
            }
        }

        if (!$i) {
            return false;
        }

        $ret = array();

        // construct type
        if ($caught['type']) {
            $ret[] = $caught['type'];
        }

        // construct image
        if ($caught['image']) {
            $ret[] = $caught['image'];
        }

        // construct position
        if ($caught['position']) {
            $ret[] = $caught['position'];
        }

        if (empty($ret)) {
            return false;
        }
        return implode(' ', $ret);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Framework class for strings that involve multiple values.
 *
 * Certain CSS properties such as border-width and margin allow multiple
 * lengths to be specified.  This class can take a vanilla border-width
 * definition and multiply it, usually into a max of four.
 *
 * @note Even though the CSS specification isn't clear about it, inherit
 *       can only be used alone: it will never manifest as part of a multi
 *       shorthand declaration.  Thus, this class does not allow inherit.
 */
class HTMLPurifier_AttrDef_CSS_Multiple extends HTMLPurifier_AttrDef
{
    /**
     * Instance of component definition to defer validation to.
     * @type HTMLPurifier_AttrDef
     * @todo Make protected
     */
    public $single;

    /**
     * Max number of values allowed.
     * @todo Make protected
     */
    public $max;

    /**
     * @param HTMLPurifier_AttrDef $single HTMLPurifier_AttrDef to multiply
     * @param int $max Max number of values allowed (usually four)
     */
    public function __construct($single, $max = 4)
    {
        $this->single = $single;
        $this->max = $max;
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = $this->mungeRgb($this->parseCDATA($string));
        if ($string === '') {
            return false;
        }
        $parts = explode(' ', $string); // parseCDATA replaced \r, \t and \n
        $length = count($parts);
        $final = '';
        for ($i = 0, $num = 0; $i < $length && $num < $this->max; $i++) {
            if (ctype_space($parts[$i])) {
                continue;
            }
            $result = $this->single->validate($parts[$i], $config, $context);
            if ($result !== false) {
                $final .= $result . ' ';
                $num++;
            }
        }
        if ($final === '') {
            return false;
        }
        return rtrim($final);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates a number as defined by the CSS spec.
 */
class HTMLPurifier_AttrDef_CSS_Number extends HTMLPurifier_AttrDef
{

    /**
     * Indicates whether or not only positive values are allowed.
     * @type bool
     */
    protected $non_negative = false;

    /**
     * @param bool $non_negative indicates whether negatives are forbidden
     */
    public function __construct($non_negative = false)
    {
        $this->non_negative = $non_negative;
    }

    /**
     * @param string $number
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return string|bool
     * @warning Some contexts do not pass $config, $context. These
     *          variables should not be used without checking HTMLPurifier_Length
     */
    public function validate($number, $config, $context)
    {
        $number = $this->parseCDATA($number);

        if ($number === '') {
            return false;
        }
        if ($number === '0') {
            return '0';
        }

        $sign = '';
        switch ($number[0]) {
            case '-':
                if ($this->non_negative) {
                    return false;
                }
                $sign = '-';
            case '+':
                $number = substr($number, 1);
        }

        if (ctype_digit($number)) {
            $number = ltrim($number, '0');
            return $number ? $sign . $number : '0';
        }

        // Period is the only non-numeric character allowed
        if (strpos($number, '.') === false) {
            return false;
        }

        list($left, $right) = explode('.', $number, 2);

        if ($left === '' && $right === '') {
            return false;
        }
        if ($left !== '' && !ctype_digit($left)) {
            return false;
        }

        $left = ltrim($left, '0');
        $right = rtrim($right, '0');

        if ($right === '') {
            return $left ? $sign . $left : '0';
        } elseif (!ctype_digit($right)) {
            return false;
        }
        return $sign . $left . '.' . $right;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates a Percentage as defined by the CSS spec.
 */
class HTMLPurifier_AttrDef_CSS_Percentage extends HTMLPurifier_AttrDef
{

    /**
     * Instance to defer number validation to.
     * @type HTMLPurifier_AttrDef_CSS_Number
     */
    protected $number_def;

    /**
     * @param bool $non_negative Whether to forbid negative values
     */
    public function __construct($non_negative = false)
    {
        $this->number_def = new HTMLPurifier_AttrDef_CSS_Number($non_negative);
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = $this->parseCDATA($string);

        if ($string === '') {
            return false;
        }
        $length = strlen($string);
        if ($length === 1) {
            return false;
        }
        if ($string[$length - 1] !== '%') {
            return false;
        }

        $number = substr($string, 0, $length - 1);
        $number = $this->number_def->validate($number, $config, $context);

        if ($number === false) {
            return false;
        }
        return "$number%";
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates the value for the CSS property text-decoration
 * @note This class could be generalized into a version that acts sort of
 *       like Enum except you can compound the allowed values.
 */
class HTMLPurifier_AttrDef_CSS_TextDecoration extends HTMLPurifier_AttrDef
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        static $allowed_values = array(
            'line-through' => true,
            'overline' => true,
            'underline' => true,
        );

        $string = strtolower($this->parseCDATA($string));

        if ($string === 'none') {
            return $string;
        }

        $parts = explode(' ', $string);
        $final = '';
        foreach ($parts as $part) {
            if (isset($allowed_values[$part])) {
                $final .= $part . ' ';
            }
        }
        $final = rtrim($final);
        if ($final === '') {
            return false;
        }
        return $final;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates a URI in CSS syntax, which uses url('http://example.com')
 * @note While theoretically speaking a URI in a CSS document could
 *       be non-embedded, as of CSS2 there is no such usage so we're
 *       generalizing it. This may need to be changed in the future.
 * @warning Since HTMLPurifier_AttrDef_CSS blindly uses semicolons as
 *          the separator, you cannot put a literal semicolon in
 *          in the URI. Try percent encoding it, in that case.
 */
class HTMLPurifier_AttrDef_CSS_URI extends HTMLPurifier_AttrDef_URI
{

    public function __construct()
    {
        parent::__construct(true); // always embedded
    }

    /**
     * @param string $uri_string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($uri_string, $config, $context)
    {
        // parse the URI out of the string and then pass it onto
        // the parent object

        $uri_string = $this->parseCDATA($uri_string);
        if (strpos($uri_string, 'url(') !== 0) {
            return false;
        }
        $uri_string = substr($uri_string, 4);
        if (strlen($uri_string) == 0) {
            return false;
        }
        $new_length = strlen($uri_string) - 1;
        if ($uri_string[$new_length] != ')') {
            return false;
        }
        $uri = trim(substr($uri_string, 0, $new_length));

        if (!empty($uri) && ($uri[0] == "'" || $uri[0] == '"')) {
            $quote = $uri[0];
            $new_length = strlen($uri) - 1;
            if ($uri[$new_length] !== $quote) {
                return false;
            }
            $uri = substr($uri, 1, $new_length - 1);
        }

        $uri = $this->expandCSSEscape($uri);

        $result = parent::validate($uri, $config, $context);

        if ($result === false) {
            return false;
        }

        // extra sanity check; should have been done by URI
        $result = str_replace(array('"', "\\", "\n", "\x0c", "\r"), "", $result);

        // suspicious characters are ()'; we're going to percent encode
        // them for safety.
        $result = str_replace(array('(', ')', "'"), array('%28', '%29', '%27'), $result);

        // there's an extra bug where ampersands lose their escaping on
        // an innerHTML cycle, so a very unlucky query parameter could
        // then change the meaning of the URL.  Unfortunately, there's
        // not much we can do about that...
        return "url(\"$result\")";
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Dummy AttrDef that mimics another AttrDef, BUT it generates clones
 * with make.
 */
class HTMLPurifier_AttrDef_Clone extends HTMLPurifier_AttrDef
{
    /**
     * What we're cloning.
     * @type HTMLPurifier_AttrDef
     */
    protected $clone;

    /**
     * @param HTMLPurifier_AttrDef $clone
     */
    public function __construct($clone)
    {
        $this->clone = $clone;
    }

    /**
     * @param string $v
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($v, $config, $context)
    {
        return $this->clone->validate($v, $config, $context);
    }

    /**
     * @param string $string
     * @return HTMLPurifier_AttrDef
     */
    public function make($string)
    {
        return clone $this->clone;
    }
}

// vim: et sw=4 sts=4


code:
<?php

// Enum = Enumerated
/**
 * Validates a keyword against a list of valid values.
 * @warning The case-insensitive compare of this function uses PHP's
 *          built-in strtolower and ctype_lower functions, which may
 *          cause problems with international comparisons
 */
class HTMLPurifier_AttrDef_Enum extends HTMLPurifier_AttrDef
{

    /**
     * Lookup table of valid values.
     * @type array
     * @todo Make protected
     */
    public $valid_values = array();

    /**
     * Bool indicating whether or not enumeration is case sensitive.
     * @note In general this is always case insensitive.
     */
    protected $case_sensitive = false; // values according to W3C spec

    /**
     * @param array $valid_values List of valid values
     * @param bool $case_sensitive Whether or not case sensitive
     */
    public function __construct($valid_values = array(), $case_sensitive = false)
    {
        $this->valid_values = array_flip($valid_values);
        $this->case_sensitive = $case_sensitive;
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = trim($string);
        if (!$this->case_sensitive) {
            // we may want to do full case-insensitive libraries
            $string = ctype_lower($string) ? $string : strtolower($string);
        }
        $result = isset($this->valid_values[$string]);

        return $result ? $string : false;
    }

    /**
     * @param string $string In form of comma-delimited list of case-insensitive
     *      valid values. Example: "foo,bar,baz". Prepend "s:" to make
     *      case sensitive
     * @return HTMLPurifier_AttrDef_Enum
     */
    public function make($string)
    {
        if (strlen($string) > 2 && $string[0] == 's' && $string[1] == ':') {
            $string = substr($string, 2);
            $sensitive = true;
        } else {
            $sensitive = false;
        }
        $values = explode(',', $string);
        return new HTMLPurifier_AttrDef_Enum($values, $sensitive);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates a boolean attribute
 */
class HTMLPurifier_AttrDef_HTML_Bool extends HTMLPurifier_AttrDef
{

    /**
     * @type bool
     */
    protected $name;

    /**
     * @type bool
     */
    public $minimized = true;

    /**
     * @param bool $name
     */
    public function __construct($name = false)
    {
        $this->name = $name;
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        return $this->name;
    }

    /**
     * @param string $string Name of attribute
     * @return HTMLPurifier_AttrDef_HTML_Bool
     */
    public function make($string)
    {
        return new HTMLPurifier_AttrDef_HTML_Bool($string);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Implements special behavior for class attribute (normally NMTOKENS)
 */
class HTMLPurifier_AttrDef_HTML_Class extends HTMLPurifier_AttrDef_HTML_Nmtokens
{
    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    protected function split($string, $config, $context)
    {
        // really, this twiddle should be lazy loaded
        $name = $config->getDefinition('HTML')->doctype->name;
        if ($name == "XHTML 1.1" || $name == "XHTML 2.0") {
            return parent::split($string, $config, $context);
        } else {
            return preg_split('/\s+/', $string);
        }
    }

    /**
     * @param array $tokens
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return array
     */
    protected function filter($tokens, $config, $context)
    {
        $allowed = $config->get('Attr.AllowedClasses');
        $forbidden = $config->get('Attr.ForbiddenClasses');
        $ret = array();
        foreach ($tokens as $token) {
            if (($allowed === null || isset($allowed[$token])) &&
                !isset($forbidden[$token]) &&
                // We need this O(n) check because of PHP's array
                // implementation that casts -0 to 0.
                !in_array($token, $ret, true)
            ) {
                $ret[] = $token;
            }
        }
        return $ret;
    }
}


code:
<?php

/**
 * Validates a color according to the HTML spec.
 */
class HTMLPurifier_AttrDef_HTML_Color extends HTMLPurifier_AttrDef
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        static $colors = null;
        if ($colors === null) {
            $colors = $config->get('Core.ColorKeywords');
        }

        $string = trim($string);

        if (empty($string)) {
            return false;
        }
        $lower = strtolower($string);
        if (isset($colors[$lower])) {
            return $colors[$lower];
        }
        if ($string[0] === '#') {
            $hex = substr($string, 1);
        } else {
            $hex = $string;
        }

        $length = strlen($hex);
        if ($length !== 3 && $length !== 6) {
            return false;
        }
        if (!ctype_xdigit($hex)) {
            return false;
        }
        if ($length === 3) {
            $hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
        }
        return "#$hex";
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Special-case enum attribute definition that lazy loads allowed frame targets
 */
class HTMLPurifier_AttrDef_HTML_FrameTarget extends HTMLPurifier_AttrDef_Enum
{

    /**
     * @type array
     */
    public $valid_values = false; // uninitialized value

    /**
     * @type bool
     */
    protected $case_sensitive = false;

    public function __construct()
    {
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        if ($this->valid_values === false) {
            $this->valid_values = $config->get('Attr.AllowedFrameTargets');
        }
        return parent::validate($string, $config, $context);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates the HTML attribute ID.
 * @warning Even though this is the id processor, it
 *          will ignore the directive Attr:IDBlacklist, since it will only
 *          go according to the ID accumulator. Since the accumulator is
 *          automatically generated, it will have already absorbed the
 *          blacklist. If you're hacking around, make sure you use load()!
 */

class HTMLPurifier_AttrDef_HTML_ID extends HTMLPurifier_AttrDef
{

    // selector is NOT a valid thing to use for IDREFs, because IDREFs
    // *must* target IDs that exist, whereas selector #ids do not.

    /**
     * Determines whether or not we're validating an ID in a CSS
     * selector context.
     * @type bool
     */
    protected $selector;

    /**
     * @param bool $selector
     */
    public function __construct($selector = false)
    {
        $this->selector = $selector;
    }

    /**
     * @param string $id
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($id, $config, $context)
    {
        if (!$this->selector && !$config->get('Attr.EnableID')) {
            return false;
        }

        $id = trim($id); // trim it first

        if ($id === '') {
            return false;
        }

        $prefix = $config->get('Attr.IDPrefix');
        if ($prefix !== '') {
            $prefix .= $config->get('Attr.IDPrefixLocal');
            // prevent re-appending the prefix
            if (strpos($id, $prefix) !== 0) {
                $id = $prefix . $id;
            }
        } elseif ($config->get('Attr.IDPrefixLocal') !== '') {
            trigger_error(
                '%Attr.IDPrefixLocal cannot be used unless ' .
                '%Attr.IDPrefix is set',
                E_USER_WARNING
            );
        }

        if (!$this->selector) {
            $id_accumulator =& $context->get('IDAccumulator');
            if (isset($id_accumulator->ids[$id])) {
                return false;
            }
        }

        // we purposely avoid using regex, hopefully this is faster

        if ($config->get('Attr.ID.HTML5') === true) {
            if (preg_match('/[\t\n\x0b\x0c ]/', $id)) {
                return false;
            }
        } else {
            if (ctype_alpha($id)) {
                // OK
            } else {
                if (!ctype_alpha(@$id[0])) {
                    return false;
                }
                // primitive style of regexps, I suppose
                $trim = trim(
                    $id,
                    'A..Za..z0..9:-._'
                );
                if ($trim !== '') {
                    return false;
                }
            }
        }

        $regexp = $config->get('Attr.IDBlacklistRegexp');
        if ($regexp && preg_match($regexp, $id)) {
            return false;
        }

        if (!$this->selector) {
            $id_accumulator->add($id);
        }

        // if no change was made to the ID, return the result
        // else, return the new id if stripping whitespace made it
        //     valid, or return false.
        return $id;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates the HTML type length (not to be confused with CSS's length).
 *
 * This accepts integer pixels or percentages as lengths for certain
 * HTML attributes.
 */

class HTMLPurifier_AttrDef_HTML_Length extends HTMLPurifier_AttrDef_HTML_Pixels
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = trim($string);
        if ($string === '') {
            return false;
        }

        $parent_result = parent::validate($string, $config, $context);
        if ($parent_result !== false) {
            return $parent_result;
        }

        $length = strlen($string);
        $last_char = $string[$length - 1];

        if ($last_char !== '%') {
            return false;
        }

        $points = substr($string, 0, $length - 1);

        if (!is_numeric($points)) {
            return false;
        }

        $points = (int)$points;

        if ($points < 0) {
            return '0%';
        }
        if ($points > 100) {
            return '100%';
        }
        return ((string)$points) . '%';
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates a rel/rev link attribute against a directive of allowed values
 * @note We cannot use Enum because link types allow multiple
 *       values.
 * @note Assumes link types are ASCII text
 */
class HTMLPurifier_AttrDef_HTML_LinkTypes extends HTMLPurifier_AttrDef
{

    /**
     * Name config attribute to pull.
     * @type string
     */
    protected $name;

    /**
     * @param string $name
     */
    public function __construct($name)
    {
        $configLookup = array(
            'rel' => 'AllowedRel',
            'rev' => 'AllowedRev'
        );
        if (!isset($configLookup[$name])) {
            trigger_error(
                'Unrecognized attribute name for link ' .
                'relationship.',
                E_USER_ERROR
            );
            return;
        }
        $this->name = $configLookup[$name];
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $allowed = $config->get('Attr.' . $this->name);
        if (empty($allowed)) {
            return false;
        }

        $string = $this->parseCDATA($string);
        $parts = explode(' ', $string);

        // lookup to prevent duplicates
        $ret_lookup = array();
        foreach ($parts as $part) {
            $part = strtolower(trim($part));
            if (!isset($allowed[$part])) {
                continue;
            }
            $ret_lookup[$part] = true;
        }

        if (empty($ret_lookup)) {
            return false;
        }
        $string = implode(' ', array_keys($ret_lookup));
        return $string;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates a MultiLength as defined by the HTML spec.
 *
 * A multilength is either a integer (pixel count), a percentage, or
 * a relative number.
 */
class HTMLPurifier_AttrDef_HTML_MultiLength extends HTMLPurifier_AttrDef_HTML_Length
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = trim($string);
        if ($string === '') {
            return false;
        }

        $parent_result = parent::validate($string, $config, $context);
        if ($parent_result !== false) {
            return $parent_result;
        }

        $length = strlen($string);
        $last_char = $string[$length - 1];

        if ($last_char !== '*') {
            return false;
        }

        $int = substr($string, 0, $length - 1);

        if ($int == '') {
            return '*';
        }
        if (!is_numeric($int)) {
            return false;
        }

        $int = (int)$int;
        if ($int < 0) {
            return false;
        }
        if ($int == 0) {
            return '0';
        }
        if ($int == 1) {
            return '*';
        }
        return ((string)$int) . '*';
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates contents based on NMTOKENS attribute type.
 */
class HTMLPurifier_AttrDef_HTML_Nmtokens extends HTMLPurifier_AttrDef
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = trim($string);

        // early abort: '' and '0' (strings that convert to false) are invalid
        if (!$string) {
            return false;
        }

        $tokens = $this->split($string, $config, $context);
        $tokens = $this->filter($tokens, $config, $context);
        if (empty($tokens)) {
            return false;
        }
        return implode(' ', $tokens);
    }

    /**
     * Splits a space separated list of tokens into its constituent parts.
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return array
     */
    protected function split($string, $config, $context)
    {
        // OPTIMIZABLE!
        // do the preg_match, capture all subpatterns for reformulation

        // we don't support U+00A1 and up codepoints or
        // escaping because I don't know how to do that with regexps
        // and plus it would complicate optimization efforts (you never
        // see that anyway).
        $pattern = '/(?:(?<=\s)|\A)' . // look behind for space or string start
            '((?:--|-?[A-Za-z_])[A-Za-z_\-0-9]*)' .
            '(?:(?=\s)|\z)/'; // look ahead for space or string end
        preg_match_all($pattern, $string, $matches);
        return $matches[1];
    }

    /**
     * Template method for removing certain tokens based on arbitrary criteria.
     * @note If we wanted to be really functional, we'd do an array_filter
     *       with a callback. But... we're not.
     * @param array $tokens
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return array
     */
    protected function filter($tokens, $config, $context)
    {
        return $tokens;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates an integer representation of pixels according to the HTML spec.
 */
class HTMLPurifier_AttrDef_HTML_Pixels extends HTMLPurifier_AttrDef
{

    /**
     * @type int
     */
    protected $max;

    /**
     * @param int $max
     */
    public function __construct($max = null)
    {
        $this->max = $max;
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = trim($string);
        if ($string === '0') {
            return $string;
        }
        if ($string === '') {
            return false;
        }
        $length = strlen($string);
        if (substr($string, $length - 2) == 'px') {
            $string = substr($string, 0, $length - 2);
        }
        if (!is_numeric($string)) {
            return false;
        }
        $int = (int)$string;

        if ($int < 0) {
            return '0';
        }

        // upper-bound value, extremely high values can
        // crash operating systems, see <http://ha.ckers.org/imagecrash.html>
        // WARNING, above link WILL crash you if you're using Windows

        if ($this->max !== null && $int > $this->max) {
            return (string)$this->max;
        }
        return (string)$int;
    }

    /**
     * @param string $string
     * @return HTMLPurifier_AttrDef
     */
    public function make($string)
    {
        if ($string === '') {
            $max = null;
        } else {
            $max = (int)$string;
        }
        $class = get_class($this);
        return new $class($max);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates an integer.
 * @note While this class was modeled off the CSS definition, no currently
 *       allowed CSS uses this type.  The properties that do are: widows,
 *       orphans, z-index, counter-increment, counter-reset.  Some of the
 *       HTML attributes, however, find use for a non-negative version of this.
 */
class HTMLPurifier_AttrDef_Integer extends HTMLPurifier_AttrDef
{

    /**
     * Whether or not negative values are allowed.
     * @type bool
     */
    protected $negative = true;

    /**
     * Whether or not zero is allowed.
     * @type bool
     */
    protected $zero = true;

    /**
     * Whether or not positive values are allowed.
     * @type bool
     */
    protected $positive = true;

    /**
     * @param $negative Bool indicating whether or not negative values are allowed
     * @param $zero Bool indicating whether or not zero is allowed
     * @param $positive Bool indicating whether or not positive values are allowed
     */
    public function __construct($negative = true, $zero = true, $positive = true)
    {
        $this->negative = $negative;
        $this->zero = $zero;
        $this->positive = $positive;
    }

    /**
     * @param string $integer
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($integer, $config, $context)
    {
        $integer = $this->parseCDATA($integer);
        if ($integer === '') {
            return false;
        }

        // we could possibly simply typecast it to integer, but there are
        // certain fringe cases that must not return an integer.

        // clip leading sign
        if ($this->negative && $integer[0] === '-') {
            $digits = substr($integer, 1);
            if ($digits === '0') {
                $integer = '0';
            } // rm minus sign for zero
        } elseif ($this->positive && $integer[0] === '+') {
            $digits = $integer = substr($integer, 1); // rm unnecessary plus
        } else {
            $digits = $integer;
        }

        // test if it's numeric
        if (!ctype_digit($digits)) {
            return false;
        }

        // perform scope tests
        if (!$this->zero && $integer == 0) {
            return false;
        }
        if (!$this->positive && $integer > 0) {
            return false;
        }
        if (!$this->negative && $integer < 0) {
            return false;
        }

        return $integer;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates the HTML attribute lang, effectively a language code.
 * @note Built according to RFC 3066, which obsoleted RFC 1766
 */
class HTMLPurifier_AttrDef_Lang extends HTMLPurifier_AttrDef
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $string = trim($string);
        if (!$string) {
            return false;
        }

        $subtags = explode('-', $string);
        $num_subtags = count($subtags);

        if ($num_subtags == 0) { // sanity check
            return false;
        }

        // process primary subtag : $subtags[0]
        $length = strlen($subtags[0]);
        switch ($length) {
            case 0:
                return false;
            case 1:
                if (!($subtags[0] == 'x' || $subtags[0] == 'i')) {
                    return false;
                }
                break;
            case 2:
            case 3:
                if (!ctype_alpha($subtags[0])) {
                    return false;
                } elseif (!ctype_lower($subtags[0])) {
                    $subtags[0] = strtolower($subtags[0]);
                }
                break;
            default:
                return false;
        }

        $new_string = $subtags[0];
        if ($num_subtags == 1) {
            return $new_string;
        }

        // process second subtag : $subtags[1]
        $length = strlen($subtags[1]);
        if ($length == 0 || ($length == 1 && $subtags[1] != 'x') || $length > 8 || !ctype_alnum($subtags[1])) {
            return $new_string;
        }
        if (!ctype_lower($subtags[1])) {
            $subtags[1] = strtolower($subtags[1]);
        }

        $new_string .= '-' . $subtags[1];
        if ($num_subtags == 2) {
            return $new_string;
        }

        // process all other subtags, index 2 and up
        for ($i = 2; $i < $num_subtags; $i++) {
            $length = strlen($subtags[$i]);
            if ($length == 0 || $length > 8 || !ctype_alnum($subtags[$i])) {
                return $new_string;
            }
            if (!ctype_lower($subtags[$i])) {
                $subtags[$i] = strtolower($subtags[$i]);
            }
            $new_string .= '-' . $subtags[$i];
        }
        return $new_string;
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Decorator that, depending on a token, switches between two definitions.
 */
class HTMLPurifier_AttrDef_Switch
{

    /**
     * @type string
     */
    protected $tag;

    /**
     * @type HTMLPurifier_AttrDef
     */
    protected $withTag;

    /**
     * @type HTMLPurifier_AttrDef
     */
    protected $withoutTag;

    /**
     * @param string $tag Tag name to switch upon
     * @param HTMLPurifier_AttrDef $with_tag Call if token matches tag
     * @param HTMLPurifier_AttrDef $without_tag Call if token doesn't match, or there is no token
     */
    public function __construct($tag, $with_tag, $without_tag)
    {
        $this->tag = $tag;
        $this->withTag = $with_tag;
        $this->withoutTag = $without_tag;
    }

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $token = $context->get('CurrentToken', true);
        if (!$token || $token->name !== $this->tag) {
            return $this->withoutTag->validate($string, $config, $context);
        } else {
            return $this->withTag->validate($string, $config, $context);
        }
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates arbitrary text according to the HTML spec.
 */
class HTMLPurifier_AttrDef_Text extends HTMLPurifier_AttrDef
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        return $this->parseCDATA($string);
    }
}

// vim: et sw=4 sts=4


code:
<?php

/**
 * Validates a URI as defined by RFC 3986.
 * @note Scheme-specific mechanics deferred to HTMLPurifier_URIScheme
 */
class HTMLPurifier_AttrDef_URI extends HTMLPurifier_AttrDef
{

    /**
     * @type HTMLPurifier_URIParser
     */
    protected $parser;

    /**
     * @type bool
     */
    protected $embedsResource;

    /**
     * @param bool $embeds_resource Does the URI here result in an extra HTTP request?
     */
    public function __construct($embeds_resource = false)
    {
        $this->parser = new HTMLPurifier_URIParser();
        $this->embedsResource = (bool)$embeds_resource;
    }

    /**
     * @param string $string
     * @return HTMLPurifier_AttrDef_URI
     */
    public function make($string)
    {
        $embeds = ($string === 'embedded');
        return new HTMLPurifier_AttrDef_URI($embeds);
    }

    /**
     * @param string $uri
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($uri, $config, $context)
    {
        if ($config->get('URI.Disable')) {
            return false;
        }

        $uri = $this->parseCDATA($uri);

        // parse the URI
        $uri = $this->parser->parse($uri);
        if ($uri === false) {
            return false;
        }

        // add embedded flag to context for validators
        $context->register('EmbeddedURI', $this->embedsResource);

        $ok = false;
        do {

            // generic validation
            $result = $uri->validate($config, $context);
            if (!$result) {
                break;
            }

            // chained filtering
            $uri_def = $config->getDefinition('URI');
            $result = $uri_def->filter($uri, $config, $context);
            if (!$result) {
                break;
            }

            // scheme-specific validation
            $scheme_obj = $uri->getSchemeObj($config, $context);
            if (!$scheme_obj) {
                break;
            }
            if ($this->embedsResource && !$scheme_obj->browsable) {
                break;
            }
            $result = $scheme_obj->validate($uri, $config, $context);
            if (!$result) {
                break;
            }

            // Post chained filtering
            $result = $uri_def->postFilter($uri, $config, $context);
            if (!$result) {
                break;
            }

            // survived gauntlet
            $ok = true;

        } while (false);

        $context->destroy('EmbeddedURI');
        if (!$ok) {
            return false;
        }
        // back to string
        return $uri->toString();
    }
}

// vim: et sw=4 sts=4


code:
<?php

abstract class HTMLPurifier_AttrDef_URI_Email extends HTMLPurifier_AttrDef
{

    /**
     * Unpacks a mailbox into its display-name and address
     * @param string $string
     * @return mixed
     */
    public function unpack($string)
    {
        // needs to be implemented
    }

}

// sub-implementations

// vim: et sw=4 sts=4


code:
<?php

/**
 * Primitive email validation class based on the regexp found at
 * http://www.regular-expressions.info/email.html
 */
class HTMLPurifier_AttrDef_URI_Email_SimpleCheck extends HTMLPurifier_AttrDef_URI_Email
{

    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        // no support for named mailboxes i.e. "Bob <bob@example.com>"
        // that needs more percent encoding to be done
        if ($string == '') {
            return false;
        }
        $string = trim($string);
        $result = preg_match('/^[A-Z0-9._%-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i', $string);
        return $result ? $string : false;
    }
}

// vim: et sw=4 sts=4