--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\CssSelector\Parser;
+
+/**
+ * CSS selector reader.
+ *
+ * This component is a port of the Python cssselect library,
+ * which is copyright Ian Bicking, @see https://github.com/SimonSapin/cssselect.
+ *
+ * @author Jean-François Simon <jeanfrancois.simon@sensiolabs.com>
+ *
+ * @internal
+ */
+class Reader
+{
+ /**
+ * @var string
+ */
+ private $source;
+
+ /**
+ * @var int
+ */
+ private $length;
+
+ /**
+ * @var int
+ */
+ private $position = 0;
+
+ /**
+ * @param string $source
+ */
+ public function __construct($source)
+ {
+ $this->source = $source;
+ $this->length = strlen($source);
+ }
+
+ /**
+ * @return bool
+ */
+ public function isEOF()
+ {
+ return $this->position >= $this->length;
+ }
+
+ /**
+ * @return int
+ */
+ public function getPosition()
+ {
+ return $this->position;
+ }
+
+ /**
+ * @return int
+ */
+ public function getRemainingLength()
+ {
+ return $this->length - $this->position;
+ }
+
+ /**
+ * @param int $length
+ * @param int $offset
+ *
+ * @return string
+ */
+ public function getSubstring($length, $offset = 0)
+ {
+ return substr($this->source, $this->position + $offset, $length);
+ }
+
+ /**
+ * @param string $string
+ *
+ * @return int
+ */
+ public function getOffset($string)
+ {
+ $position = strpos($this->source, $string, $this->position);
+
+ return false === $position ? false : $position - $this->position;
+ }
+
+ /**
+ * @param string $pattern
+ *
+ * @return bool
+ */
+ public function findPattern($pattern)
+ {
+ $source = substr($this->source, $this->position);
+
+ if (preg_match($pattern, $source, $matches)) {
+ return $matches;
+ }
+
+ return false;
+ }
+
+ /**
+ * @param int $length
+ */
+ public function moveForward($length)
+ {
+ $this->position += $length;
+ }
+
+ public function moveToEnd()
+ {
+ $this->position = $this->length;
+ }
+}