javascript hashmap:HashMap的JavaScript實現

function hashMap(){
/**
* Map大小
*/
var size = 0;
/**
* 容器預設最大長度
*/
var length = 256
var loadfactor = 0.75;
/**
* 質數
*/
var prime = 1000000;
/**
* 對象
*/
var table = new Array(length);
/**
* 設定構建Hash質數
* @param {Object} p
*/
this.setPrime = function(p){
this.prime = p;
}
/**
* 擷取構建Hash質數
*/
this.getPrime = function(){
return this.prime;
}
/**
* 當期的Hash值計算方法
*/
this.hash = BKDRHash;
/**
* HashMap的put方法
* @param {Object} key
* @param {Object} value
*/
this.put = function(key, value){
/**
* 如果裝填因子大於0.75則重新Hash
*/
if (size / length > loadfactor) {
rehash(this);
}
var counter = 0;
var code = this.hash(key);
//如果指定位置為空白，則直接存放
if (typeof table[code] == 'undefined') {
size = size + 1;
table[code] = new Entry(key, value);
//如果指定位置不為空白並且Key值相等，則覆蓋
}
else
if (table[code].key == key) {
table[code].value == value;
}
//發生散列衝突
else {
var entry = table[code];
// 訪問Hash鏈表
while(entry.next != undefined){
entry = entry.next;
if(entry.key == key){
//覆蓋
entry.value =
value;
break;
}else if(entry.next == undefined){
//新增
entry.next = new Entry(key,value);
entry.next.prev = entry;
size = siez + 1;
break;
}
}
}
}
/**
* 通過Key從HashMap中取值
* @param {Object} key 索引值
*/
this.load = function(key){
var hashcode = this.hash(key);
if(typeof table[hashcode] != 'undefined'){
var entry = table[hashcode];
if(entry.key == key){
return entry.value;
}else {
while(entry.next!= undefined){
entry = entry.next;
if(entry.key == key){
return entry.value;
}
}
}
}
return null; 本文連結http://www.cxybl.com/html/wyzz/JavaScript_Ajax/20121114/33820.html