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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\Intl\ResourceBundle\Util;
use Symfony\Component\Intl\Exception\OutOfBoundsException;
/**
* Implements a ring buffer.
*
* A ring buffer is an array-like structure with a fixed size. If the buffer
* is full, the next written element overwrites the first bucket in the buffer,
* then the second and so on.
*
* @author Bernhard Schussek <bschussek@gmail.com>
*/
class RingBuffer implements \ArrayAccess
{
private $values = array();
private $indices = array();
private $cursor = 0;
private $size;
public function __construct($size)
{
$this->size = $size;
}
/**
* {@inheritdoc}
*/
public function offsetExists($key)
{
return isset($this->indices[$key]);
}
/**
* {@inheritdoc}
*/
public function offsetGet($key)
{
if (!isset($this->indices[$key])) {
throw new OutOfBoundsException(sprintf(
'The index "%s" does not exist.',
$key
));
}
return $this->values[$this->indices[$key]];
}
/**
* {@inheritdoc}
*/
public function offsetSet($key, $value)
{
if (false !== ($keyToRemove = array_search($this->cursor, $this->indices))) {
unset($this->indices[$keyToRemove]);
}
$this->values[$this->cursor] = $value;
$this->indices[$key] = $this->cursor;
$this->cursor = ($this->cursor + 1) % $this->size;
}
/**
* {@inheritdoc}
*/
public function offsetUnset($key)
{
if (isset($this->indices[$key])) {
$this->values[$this->indices[$key]] = null;
unset($this->indices[$key]);
}
}
}
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