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administrator/components/com_finder/src/Indexer/Parser.php

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+<?php
+
+/**
+ * @package     Joomla.Administrator
+ * @subpackage  com_finder
+ *
+ * @copyright   (C) 2011 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license     GNU General Public License version 2 or later; see LICENSE.txt
+ */
+
+namespace Joomla\Component\Finder\Administrator\Indexer;
+
+use Joomla\CMS\Filter\InputFilter;
+use Joomla\CMS\Language\Text;
+
+// phpcs:disable PSR1.Files.SideEffects
+\defined('_JEXEC') or die;
+// phpcs:enable PSR1.Files.SideEffects
+
+/**
+ * Parser base class for the Finder indexer package.
+ *
+ * @since  2.5
+ */
+abstract class Parser
+{
+    /**
+     * Parser support instances container.
+     *
+     * @var    Parser[]
+     * @since  4.0.0
+     */
+    protected static $instances = [];
+
+    /**
+     * Method to get a parser, creating it if necessary.
+     *
+     * @param   string  $format  The type of parser to load.
+     *
+     * @return  Parser  A Parser instance.
+     *
+     * @since   2.5
+     * @throws  \Exception on invalid parser.
+     */
+    public static function getInstance($format)
+    {
+        $format = InputFilter::getInstance()->clean($format, 'cmd');
+
+        // Only create one parser for each format.
+        if (isset(self::$instances[$format])) {
+            return self::$instances[$format];
+        }
+
+        // Setup the adapter for the parser.
+        $class = '\\Joomla\\Component\\Finder\\Administrator\\Indexer\\Parser\\' . ucfirst($format);
+
+        // Check if a parser exists for the format.
+        if (class_exists($class)) {
+            self::$instances[$format] = new $class();
+
+            return self::$instances[$format];
+        }
+
+        // Throw invalid format exception.
+        throw new \Exception(Text::sprintf('COM_FINDER_INDEXER_INVALID_PARSER', $format));
+    }
+
+    /**
+     * Method to parse input and extract the plain text. Because this method is
+     * called from both inside and outside the indexer, it needs to be able to
+     * batch out its parsing functionality to deal with the inefficiencies of
+     * regular expressions. We will parse recursively in 2KB chunks.
+     *
+     * @param   string  $input  The input to parse.
+     *
+     * @return  string  The plain text input.
+     *
+     * @since   2.5
+     */
+    public function parse($input)
+    {
+        // If the input is less than 2KB we can parse it in one go.
+        if (strlen($input) <= 2048) {
+            return $this->process($input);
+        }
+
+        // Input is longer than 2Kb so parse it in chunks of 2Kb or less.
+        $start  = 0;
+        $end    = strlen($input);
+        $chunk  = 2048;
+        $return = null;
+
+        while ($start < $end) {
+            // Setup the string.
+            $string = substr($input, $start, $chunk);
+
+            // Find the last space character if we aren't at the end.
+            $ls = (($start + $chunk) < $end ? strrpos($string, ' ') : false);
+
+            // Truncate to the last space character (but include it in the string).
+            if ($ls !== false) {
+                $string = substr($string, 0, $ls + 1);
+            }
+
+            // Adjust the start position for the next iteration.
+            $start += $ls !== false ? $ls + 1 : $chunk;
+
+            // Parse the chunk.
+            $return .= $this->process($string);
+        }
+
+        return $return;
+    }
+
+    /**
+     * Method to process input and extract the plain text.
+     *
+     * @param   string  $input  The input to process.
+     *
+     * @return  string  The plain text input.
+     *
+     * @since   2.5
+     */
+    abstract protected function process($input);
+}