Proyectos de Subversion Moodle

<?php

// if want to implement error collecting here, we'll need to use some sort

// of global data (probably trigger_error) because it's impossible to pass

// $config or $context to the callback functions.

/**

 * Handles referencing and derefencing character entities

 */

class HTMLPurifier_EntityParser

{

    /**

     * Reference to entity lookup table.

     * @type HTMLPurifier_EntityLookup

     */

    protected $_entity_lookup;

    /**

     * Callback regex string for entities in text.

     * @type string

     */

    protected $_textEntitiesRegex;

    /**

     * Callback regex string for entities in attributes.

     * @type string

     */

    protected $_attrEntitiesRegex;

    /**

     * Tests if the beginning of a string is a semi-optional regex

     */

    protected $_semiOptionalPrefixRegex;

    public function __construct() {

        // From

        // http://stackoverflow.com/questions/15532252/why-is-reg-being-rendered-as-without-the-bounding-semicolon

        $semi_optional = "quot|QUOT|lt|LT|gt|GT|amp|AMP|AElig|Aacute|Acirc|Agrave|Aring|Atilde|Auml|COPY|Ccedil|ETH|Eacute|Ecirc|Egrave|Euml|Iacute|Icirc|Igrave|Iuml|Ntilde|Oacute|Ocirc|Ograve|Oslash|Otilde|Ouml|REG|THORN|Uacute|Ucirc|Ugrave|Uuml|Yacute|aacute|acirc|acute|aelig|agrave|aring|atilde|auml|brvbar|ccedil|cedil|cent|copy|curren|deg|divide|eacute|ecirc|egrave|eth|euml|frac12|frac14|frac34|iacute|icirc|iexcl|igrave|iquest|iuml|laquo|macr|micro|middot|nbsp|not|ntilde|oacute|ocirc|ograve|ordf|ordm|oslash|otilde|ouml|para|plusmn|pound|raquo|reg|sect|shy|sup1|sup2|sup3|szlig|thorn|times|uacute|ucirc|ugrave|uml|uuml|yacute|yen|yuml";

        // NB: three empty captures to put the fourth match in the right

        // place

        $this->_semiOptionalPrefixRegex = "/&()()()($semi_optional)/";

        $this->_textEntitiesRegex =

            '/&(?:'.

            // hex

            '[#]x([a-fA-F0-9]+);?|'.

            // dec

            '[#]0*(\d+);?|'.

            // string (mandatory semicolon)

            // NB: order matters: match semicolon preferentially

            '([A-Za-z_:][A-Za-z0-9.\-_:]*);|'.

            // string (optional semicolon)

            "($semi_optional)".

            ')/';

        $this->_attrEntitiesRegex =

            '/&(?:'.

            // hex

            '[#]x([a-fA-F0-9]+);?|'.

            // dec

            '[#]0*(\d+);?|'.

            // string (mandatory semicolon)

            // NB: order matters: match semicolon preferentially

            '([A-Za-z_:][A-Za-z0-9.\-_:]*);|'.

            // string (optional semicolon)

            // don't match if trailing is equals or alphanumeric (URL

            // like)

            "($semi_optional)(?![=;A-Za-z0-9])".

            ')/';

    }

    /**

     * Substitute entities with the parsed equivalents.  Use this on

     * textual data in an HTML document (as opposed to attributes.)

     *

     * @param string $string String to have entities parsed.

     * @return string Parsed string.

     */

    public function substituteTextEntities($string)

    {

        return preg_replace_callback(

            $this->_textEntitiesRegex,

            array($this, 'entityCallback'),

            $string

        );

    }

    /**

     * Substitute entities with the parsed equivalents.  Use this on

     * attribute contents in documents.

     *

     * @param string $string String to have entities parsed.

     * @return string Parsed string.

     */

    public function substituteAttrEntities($string)

    {

        return preg_replace_callback(

            $this->_attrEntitiesRegex,

            array($this, 'entityCallback'),

            $string

        );

    }

    /**

     * Callback function for substituteNonSpecialEntities() that does the work.

     *

     * @param array $matches  PCRE matches array, with 0 the entire match, and

     *                  either index 1, 2 or 3 set with a hex value, dec value,

     *                  or string (respectively).

     * @return string Replacement string.

     */

    protected function entityCallback($matches)

    {

        $entity = $matches[0];

        $hex_part = @$matches[1];

        $dec_part = @$matches[2];

        $named_part = empty($matches[3]) ? (empty($matches[4]) ? "" : $matches[4]) : $matches[3];

        if ($hex_part !== NULL && $hex_part !== "") {

            return HTMLPurifier_Encoder::unichr(hexdec($hex_part));

        } elseif ($dec_part !== NULL && $dec_part !== "") {

            return HTMLPurifier_Encoder::unichr((int) $dec_part);

        } else {

            if (!$this->_entity_lookup) {

                $this->_entity_lookup = HTMLPurifier_EntityLookup::instance();

            }

            if (isset($this->_entity_lookup->table[$named_part])) {

                return $this->_entity_lookup->table[$named_part];

            } else {

                // exact match didn't match anything, so test if

                // any of the semicolon optional match the prefix.

                // Test that this is an EXACT match is important to

                // prevent infinite loop

                if (!empty($matches[3])) {

                    return preg_replace_callback(

                        $this->_semiOptionalPrefixRegex,

                        array($this, 'entityCallback'),

                        $entity

                    );

                }

                return $entity;

            }

        }

    }

    // LEGACY CODE BELOW

    /**

     * Callback regex string for parsing entities.

     * @type string

     */

    protected $_substituteEntitiesRegex =

        '/&(?:[#]x([a-fA-F0-9]+)|[#]0*(\d+)|([A-Za-z_:][A-Za-z0-9.\-_:]*));?/';

        //     1. hex             2. dec      3. string (XML style)

    /**

     * Decimal to parsed string conversion table for special entities.

     * @type array

     */

    protected $_special_dec2str =

            array(

                    34 => '"',

                    38 => '&',

                    39 => "'",

                    60 => '<',

                    62 => '>'

            );

    /**

     * Stripped entity names to decimal conversion table for special entities.

     * @type array

     */

    protected $_special_ent2dec =

            array(

                    'quot' => 34,

                    'amp'  => 38,

                    'lt'   => 60,

                    'gt'   => 62

            );

    /**

     * Substitutes non-special entities with their parsed equivalents. Since

     * running this whenever you have parsed character is t3h 5uck, we run

     * it before everything else.

     *

     * @param string $string String to have non-special entities parsed.

     * @return string Parsed string.

     */

    public function substituteNonSpecialEntities($string)

    {

        // it will try to detect missing semicolons, but don't rely on it

        return preg_replace_callback(

            $this->_substituteEntitiesRegex,

            array($this, 'nonSpecialEntityCallback'),

            $string

        );

    }

    /**

     * Callback function for substituteNonSpecialEntities() that does the work.

     *

     * @param array $matches  PCRE matches array, with 0 the entire match, and

     *                  either index 1, 2 or 3 set with a hex value, dec value,

     *                  or string (respectively).

     * @return string Replacement string.

     */

    protected function nonSpecialEntityCallback($matches)

    {

        // replaces all but big five

        $entity = $matches[0];

        $is_num = (@$matches[0][1] === '#');

        if ($is_num) {

            $is_hex = (@$entity[2] === 'x');

            $code = $is_hex ? hexdec($matches[1]) : (int) $matches[2];

            // abort for special characters

            if (isset($this->_special_dec2str[$code])) {

                return $entity;

            }

            return HTMLPurifier_Encoder::unichr($code);

        } else {

            if (isset($this->_special_ent2dec[$matches[3]])) {

                return $entity;

            }

            if (!$this->_entity_lookup) {

                $this->_entity_lookup = HTMLPurifier_EntityLookup::instance();

            }

            if (isset($this->_entity_lookup->table[$matches[3]])) {

                return $this->_entity_lookup->table[$matches[3]];

            } else {

                return $entity;

            }

        }

    }

    /**

     * Substitutes only special entities with their parsed equivalents.

     *

     * @notice We try to avoid calling this function because otherwise, it

     * would have to be called a lot (for every parsed section).

     *

     * @param string $string String to have non-special entities parsed.

     * @return string Parsed string.

     */

    public function substituteSpecialEntities($string)

    {

        return preg_replace_callback(

            $this->_substituteEntitiesRegex,

            array($this, 'specialEntityCallback'),

            $string

        );

    }

    /**

     * Callback function for substituteSpecialEntities() that does the work.

     *

     * This callback has same syntax as nonSpecialEntityCallback().

     *

     * @param array $matches  PCRE-style matches array, with 0 the entire match, and

     *                  either index 1, 2 or 3 set with a hex value, dec value,

     *                  or string (respectively).

     * @return string Replacement string.

     */

    protected function specialEntityCallback($matches)

    {

        $entity = $matches[0];

        $is_num = (@$matches[0][1] === '#');

        if ($is_num) {

            $is_hex = (@$entity[2] === 'x');

            $int = $is_hex ? hexdec($matches[1]) : (int) $matches[2];

            return isset($this->_special_dec2str[$int]) ?

                $this->_special_dec2str[$int] :

                $entity;

        } else {

            return isset($this->_special_ent2dec[$matches[3]]) ?

                $this->_special_dec2str[$this->_special_ent2dec[$matches[3]]] :

                $entity;

        }

    }

}

// vim: et sw=4 sts=4