File Source for class.apc

<?php
/**
* APC queue
* @package apc_queue
* @author Julius Beckmann
* @link http://juliusbeckmann.de/classes/apc_queue/
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
* @filesource
*/
/**
* Simple queue interface
* @package apc_queue
*/
interface queue_interface{
public function add($value);
public function get();
public function length();
}
/**
* Simple class for fifo queues saved in APC cache
* @name APC queue
* @version v0.1_2010.01.29
* @access public
* @package apc_queue
*
* Copyright 2009 Julius Beckmann
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
class apc_queue implements queue_interface {
/**
* Overall prefix for queue keys
*/
private $prefix = 'APC_QUEUE_';
/**
* Name of this queue
*/
private $name = '';
/**
* Key prefix
*/
private $key = NULL;
/**
* Key of head counter
*/
private $head = NULL;
/**
* Key of tail counter
*/
private $tail = NULL;
/**
* Creates queue object. Every queue needs a name.
* @param string $queue_name
* @param boolean $force_new
*/
public function __construct($queue_name, $force_new=FALSE) {
$this->name = (string)$queue_name;
// Defined counter keys
$this->head = $this->prefix.$this->name.'_head';
$this->tail = $this->prefix.$this->name.'_tail';
$this->key = $this->prefix.$this->name.'_';
$this->init($force_new);
}
/**
* Initializes the queue and checks for counter integrity
* @access private
* @param boolean $force_new
* @return boolean
*/
private function init($force_new=FALSE) {
if($force_new) {
// Force new queue by resettings counters
apc_store($this->head, 0);
apc_store($this->tail, 0);
}else{
// Check head counter
$success = FALSE;
$val_head = apc_fetch($this->head, $success);
if(!$success) {
apc_store($this->head, 0);
}
// Check tail counter
$success = FALSE;
$val_tail = apc_fetch($this->tail, $success);
if(!$success) {
apc_store($this->tail, 0);
}
// Check counter integrity
if($val_head < $val_tail) {
// Force new queue
$this->init(TRUE);
}
}
return TRUE;
}
/**
* Adds a value to queue
* @param mixed $value
*/
public function add($value) {
$id = apc_fetch($this->head)+1;
apc_store($this->head, $id);
apc_store($this->key.$id, $value);
return TRUE;
}
/**
* Fetches next value from queue. FALSE if empty.
* @return mixed
*/
public function get() {
// Check length
if($this->length() < 1) {
// Reset counters if queue is empty
$this->init(TRUE);
return FALSE;
}
$id = apc_fetch($this->tail)+1;
apc_store($this->tail, $id);
return apc_fetch($this->key.$id);
}
/**
* Returns queue length
* @return integer
*/
public function length() {
$head = apc_fetch($this->head);
$tail = apc_fetch($this->tail);
$length = $head - $tail;
return ($length >= 0) ? $length : 0 ;
}
}
// Check if APC has some memory left
// var_dump(apc_sma_info());
// Example:
/*
$q = new apc_queue('test', isset($_GET['force']));
echo "LENGTH: ", $q->length(), "\nSTORE: ";
for($i=0; $i<10; ++$i) {
$rand = rand(0,9);
echo $rand,',';
$q->add($rand);
}
echo "\nLENGTH: ", $q->length(), "\nFETCH: ";
while(($g = $q->get()) !== FALSE) {
echo $g,',';
}
echo "\nLENGTH: ", $q->length();
*/

Source for file class.apc_queue.php