MEMQ Class checkin

memq.class.php

@@ -0,0 +1,92 @@
+<?php
+
+	define('MEMQ_POOL', 'localhost:11211');
+	define('MEMQ_TTL', 0);
+
+	class MEMQ {
+
+		private static $mem = NULL;
+
+		private function __construct() {}
+
+		private function __clone() {}
+
+		private static function getInstance() {
+			if(!self::$mem) self::init();
+			return self::$mem;
+		}
+
+		private static function init() {
+			$mem = new Memcached;
+			$servers = explode(",", MEMQ_POOL);
+			foreach($servers as $server) {
+				list($host, $port) = explode(":", $server);
+				$mem->addServer($host, $port);
+			}
+			self::$mem = $mem;
+		}
+
+		public static function is_empty($queue) {
+			$mem = self::getInstance();
+			$head = $mem->get($queue."_head");
+			$tail = $mem->get($queue."_tail");
+
+			if($head >= $tail || $head === FALSE || $tail === FALSE) 
+				return TRUE;
+			else 
+				return FALSE;
+		}
+
+		public static function dequeue($queue, $after_id=FALSE, $till_id=FALSE) {
+			$mem = self::getInstance();
+
+			if($after_id === FALSE && $till_id === FALSE) {
+				$tail = $mem->get($queue."_tail");
+				if(($id = $mem->increment($queue."_head")) === FALSE) 
+					return FALSE;
+
+				if($id <= $tail) {
+					return $mem->get($queue."_".($id-1));
+				}
+				else {
+					$mem->decrement($queue."_head");
+					return FALSE;
+				}
+			}
+			else if($after_id !== FALSE && $till_id === FALSE) {
+				$till_id = $mem->get($queue."_tail");	
+			}
+
+			$item_keys = array();
+			for($i=$after_id+1; $i<=$till_id; $i++) 
+				$item_keys[] = $queue."_".$i;
+			$null = NULL;
+
+			return $mem->getMulti($item_keys, $null, Memcached::GET_PRESERVE_ORDER); 
+		}
+
+		public static function enqueue($queue, $item) {
+			$mem = self::getInstance();
+
+			$id = $mem->increment($queue."_tail");
+			if($id === FALSE) {
+				if($mem->add($queue."_tail", 1, MEMQ_TTL) === FALSE) {
+					$id = $mem->increment($queue."_tail");
+					if($id === FALSE) 
+						return FALSE;
+				}
+				else {
+					$id = 1;
+					$mem->add($queue."_head", $id, MEMQ_TTL);
+				}
+			}
+
+			if($mem->add($queue."_".$id, $item, MEMQ_TTL) === FALSE) 
+				return FALSE;
+
+			return $id;
+		}
+
+	}
+
+?>