From ffb1997902facb36b78a7cfa522f41f2b3d71cda Mon Sep 17 00:00:00 2001
From: Mike Macgirvin <mike@macgirvin.com>
Date: Wed, 8 Sep 2010 20:14:17 -0700
Subject: mistpark 2.0 infrasturcture lands

---
 library/HTMLPurifier/EntityParser.php | 144 ++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)
 create mode 100644 library/HTMLPurifier/EntityParser.php

(limited to 'library/HTMLPurifier/EntityParser.php')

diff --git a/library/HTMLPurifier/EntityParser.php b/library/HTMLPurifier/EntityParser.php
new file mode 100644
index 000000000..8c384472d
--- /dev/null
+++ b/library/HTMLPurifier/EntityParser.php
@@ -0,0 +1,144 @@
+<?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.
+     */
+    protected $_entity_lookup;
+
+    /**
+     * Callback regex string for parsing entities.
+     */
+    protected $_substituteEntitiesRegex =
+'/&(?:[#]x([a-fA-F0-9]+)|[#]0*(\d+)|([A-Za-z_:][A-Za-z0-9.\-_:]*));?/';
+//     1. hex             2. dec      3. string (XML style)
+
+
+    /**
+     * Decimal to parsed string conversion table for special entities.
+     */
+    protected $_special_dec2str =
+            array(
+                    34 => '"',
+                    38 => '&',
+                    39 => "'",
+                    60 => '<',
+                    62 => '>'
+            );
+
+    /**
+     * Stripped entity names to decimal conversion table for special entities.
+     */
+    protected $_special_ent2dec =
+            array(
+                    'quot' => 34,
+                    'amp'  => 38,
+                    'lt'   => 60,
+                    'gt'   => 62
+            );
+
+    /**
+     * Substitutes non-special entities with their parsed equivalents. Since
+     * running this whenever you have parsed character is t3h 5uck, we run
+     * it before everything else.
+     *
+     * @param $string String to have non-special entities parsed.
+     * @returns Parsed string.
+     */
+    public function substituteNonSpecialEntities($string) {
+        // it will try to detect missing semicolons, but don't rely on it
+        return preg_replace_callback(
+            $this->_substituteEntitiesRegex,
+            array($this, 'nonSpecialEntityCallback'),
+            $string
+            );
+    }
+
+    /**
+     * Callback function for substituteNonSpecialEntities() that does the work.
+     *
+     * @param $matches  PCRE matches array, with 0 the entire match, and
+     *                  either index 1, 2 or 3 set with a hex value, dec value,
+     *                  or string (respectively).
+     * @returns Replacement string.
+     */
+
+    protected function nonSpecialEntityCallback($matches) {
+        // replaces all but big five
+        $entity = $matches[0];
+        $is_num = (@$matches[0][1] === '#');
+        if ($is_num) {
+            $is_hex = (@$entity[2] === 'x');
+            $code = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
+
+            // abort for special characters
+            if (isset($this->_special_dec2str[$code]))  return $entity;
+
+            return HTMLPurifier_Encoder::unichr($code);
+        } else {
+            if (isset($this->_special_ent2dec[$matches[3]])) return $entity;
+            if (!$this->_entity_lookup) {
+                $this->_entity_lookup = HTMLPurifier_EntityLookup::instance();
+            }
+            if (isset($this->_entity_lookup->table[$matches[3]])) {
+                return $this->_entity_lookup->table[$matches[3]];
+            } else {
+                return $entity;
+            }
+        }
+    }
+
+    /**
+     * Substitutes only special entities with their parsed equivalents.
+     *
+     * @notice We try to avoid calling this function because otherwise, it
+     * would have to be called a lot (for every parsed section).
+     *
+     * @param $string String to have non-special entities parsed.
+     * @returns Parsed string.
+     */
+    public function substituteSpecialEntities($string) {
+        return preg_replace_callback(
+            $this->_substituteEntitiesRegex,
+            array($this, 'specialEntityCallback'),
+            $string);
+    }
+
+    /**
+     * Callback function for substituteSpecialEntities() that does the work.
+     *
+     * This callback has same syntax as nonSpecialEntityCallback().
+     *
+     * @param $matches  PCRE-style matches array, with 0 the entire match, and
+     *                  either index 1, 2 or 3 set with a hex value, dec value,
+     *                  or string (respectively).
+     * @returns Replacement string.
+     */
+    protected function specialEntityCallback($matches) {
+        $entity = $matches[0];
+        $is_num = (@$matches[0][1] === '#');
+        if ($is_num) {
+            $is_hex = (@$entity[2] === 'x');
+            $int = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
+            return isset($this->_special_dec2str[$int]) ?
+                $this->_special_dec2str[$int] :
+                $entity;
+        } else {
+            return isset($this->_special_ent2dec[$matches[3]]) ?
+                $this->_special_ent2dec[$matches[3]] :
+                $entity;
+        }
+    }
+
+}
+
+// vim: et sw=4 sts=4
-- 
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