一致性hash算法

Author: wjcgithub

consistency_hash/MemServerSetting.php

@@ -0,0 +1,85 @@
+<?php
+
+    /**
+     *
+     * Created by PhpStorm.
+     * Author: evolution
+     * Date: 16-7-8
+     * Time: 上午9:33
+     *
+     * license GPL
+     */
+    class MemServerSetting
+    {
+        //hashtable size
+        private $size = 100;
+        private static $instance;
+        private $memServer=[];
+
+        /**
+         * 初始化hash表
+         *
+         */
+        private function __construct(){
+            //部署缓存服务器
+            $this->setMemServer();
+            //设置缓存服务器的个数
+            $this->size = count($this->memServer);
+        }
+
+        private function __clone(){
+            echo 'not instance';
+        }
+
+        /**
+         * 部署缓存服务器
+         *
+         * @author: jichao.wang <[email protected]>
+         */
+        private function setMemServer(){
+            $this->memServer = [
+                ['host'=>'192.168.1.123', 'port'=>6379],
+                ['host'=>'192.168.1.321', 'port'=>6379],
+            ];
+        }
+
+        /**
+         * 选择合适的缓存服务器
+         *
+         * @author: jichao.wang <[email protected]>
+         *
+         * @param $key
+         */
+        public function getMemServer($key){
+            $index = $this->hashFunc($key);
+            return $this->memServer[$index];
+        }
+
+        /**
+         * 获取一个缓存服务的实例
+         *
+         * @author: jichao.wang <[email protected]>
+         */
+        static public function getInstance(){
+            if(empty(self::$instance)){
+                self::$instance = new MemServerSetting();
+            }
+
+            return self::$instance;
+        }
+
+        /**
+         * hash 函数
+         *
+         * @author: jichao.wang <[email protected]>
+         *
+         * @param $key
+         *
+         * @return int
+         */
+        private function hashFunc($key){
+            $sum = crc32($key);
+            return $sum % $this->size;
+        }
+
+    }

consistency_hash/index.php

@@ -0,0 +1,40 @@
+<?php
+    /**
+     * Created by PhpStorm.
+     * Author: evolution
+     * Date: 16-7-8
+     * Time: 下午4:26
+     *
+     * license GPL
+     */
+    include_once "MemServerSetting.php";
+    $mObj = MemServerSetting::getInstance();
+    print_r($mObj->getMemServer('name'));
+    print_r($mObj->getMemServer('age'));
+    print_r($mObj->getMemServer('sex'));
+
+    function chash($key){
+        $md5 = substr(md5($key),0,8);
+        echo $md5;
+        $seed = 31;
+        $hash = 0;
+
+        for($i = 0; $i<8;$i++){
+            $hash = $hash*$seed + ord($md5{$i});
+        }
+
+        echo "\r\n";
+        echo $hash;
+        echo "\r\n";
+        echo "crc32:".crc32($key);
+        echo "\r\n";
+        return $hash & 0x7FFFFFFF;
+    }
+
+    echo chash('name');
+    echo "\r\n";
+    echo 2740435799612 & 0x7FFFFFFF;
+    echo bindec(100111111000001110101100111100111000111100 & 1111111111111111111111111111111);
+    echo "\r\n";
+    echo "end";
+    echo "\r\n";