Adjust copyrights years
<?php
/**
* SeekQuarry/Yioop --
* Open Source Pure PHP Search Engine, Crawler, and Indexer
*
* Copyright (C) 2009 - 2023 Chris Pollett chris@pollett.org
*
* LICENSE:
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* END LICENSE
*
* @author Parth Patel
* @license https://www.gnu.org/licenses/ GPL3
* @link https://www.seekquarry.com/
* @copyright 2009 - 2023
* @filesource
*/
namespace seekquarry\yioop\library;
use seekquarry\yioop\library as L;
/**
* Implements a least recently used cache
*
* @author Parth Patel
*/
class LRUCache
{
/**
* An associative array that represent cache
* @var array
*/
private $cache;
/**
* Size of the cache
* @var int
*/
private $size;
/**
* Default size of LRU Cache
* @var int
*/
const DEFAULT_SIZE = 200;
/**
* Creates an empty cache and sets the size
*
* @param int $size size of the cache
*/
public function __construct($size = self::DEFAULT_SIZE)
{
$this->cache = [];
$this->size = $size;
}
/**
* Add or update a key with given value to the cache
*
* @param mixed $key used to look up value
* @param mixed $value associated to the key
* @return mixed evicted key-value pair if any
*/
public function put($key, $value)
{
//use array_key_values rather than isset as value might be null
if (array_key_exists($key, $this->cache)) {
unset($this->cache[$key]);
// move to front
$this->cache = [$key => $value] + $this->cache;
} else {
if (count($this->cache) < $this->size) {
// insert at front
$this->cache = [$key => $value] + $this->cache;
} else {
$evicted_key = array_key_last($this->cache);
$evicted_value = $this->cache[$evicted_key];
unset($this->cache[$evicted_key]);
$this->cache = [$key => $value] + $this->cache;
return [$evicted_key, $evicted_value];
}
}
}
/**
* Returns the value for a given key if found in the cache
*
* @param mixed $key used to look up value
* @return mixed $value if found
*/
public function get($key)
{
if (array_key_exists($key, $this->cache)) {
return $this->cache[$key];
}
}
/**
* Returns all the items currently in cache
*
* @return array $this->cache
*/
public function getAll()
{
return $this->cache;
}
}