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TokenStream.php
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TokenStream.php
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<?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;
/**
* TokenStream represents a stream of CSS Selector tokens.
*
* This component is a port of the Python lxml library,
* which is copyright Infrae and distributed under the BSD license.
*
* @author Fabien Potencier <fabien@symfony.com>
*/
class TokenStream
{
private $used;
private $tokens;
private $source;
private $peeked;
private $peeking;
/**
* Constructor.
*
* @param array $tokens The tokens that make the stream.
* @param mixed $source The source of the stream.
*/
public function __construct($tokens, $source = null)
{
$this->used = array();
$this->tokens = $tokens;
$this->source = $source;
$this->peeked = null;
$this->peeking = false;
}
/**
* Gets the tokens that have already been visited in this stream.
*
* @return array
*/
public function getUsed()
{
return $this->used;
}
/**
* Gets the next token in the stream or null if there is none.
* Note that if this stream was set to be peeking its behavior
* will be restored to not peeking after this operation.
*
* @return mixed
*/
public function next()
{
if ($this->peeking) {
$this->peeking = false;
$this->used[] = $this->peeked;
return $this->peeked;
}
if (!count($this->tokens)) {
return null;
}
$next = array_shift($this->tokens);
$this->used[] = $next;
return $next;
}
/**
* Peeks for the next token in this stream. This means that the next token
* will be returned but it won't be considered as used (visited) until the
* next() method is invoked.
* If there are no remaining tokens null will be returned.
*
* @see next()
*
* @return mixed
*/
public function peek()
{
if (!$this->peeking) {
if (!count($this->tokens)) {
return null;
}
$this->peeked = array_shift($this->tokens);
$this->peeking = true;
}
return $this->peeked;
}
}