php中的哈希表是什么

<?php

class HashTable

{

private $buckets;   //用于存储数据的数组

private $size = 12;   //记录buckets 数组的大小

public function __construct(){

$this->buckets = new SplFixedArray($this->size);

//SplFixedArray效率更高，也可以用一般的数组来代替

}

    private function hashfunc($key){

$strlen = strlen($key); //返回字符串的长度

$hashval = 0; 

for($i = 0; $i<$strlen ; $i++){

$hashval +=ord($key[$i]); //返回ASCII的值

}

return $hashval%12;    //    返回取余数后的值

}

public function insert($key,$value){

$index = $this->hashfunc($key);

if(isset($this->buckets[$index])){

$newNode = new HashNode($key,$value,$this->buckets[$index]);

}else{

$newNode = new HashNode($key,$value,null);

}

$this->buckets[$index] = $newNode;

}

public function find($key){

$index = $this->hashfunc($key);

$current = $this->buckets[$index];

echo "</br>";

var_dump($current);

while(isset($current)){    //遍历当前链表

if($current->key==$key){    //比较当前结点关键字

return $current->value;

}

$current = $current->nextNode;

//return $current->value;

}

return NULL;

}

}

 class HashNode{

public $key;  //关键字

public $value;  //数据

public $nextNode; //HASHNODE来存储信息

public function __construct($key,$value,$nextNode = NULL){

$this->key = $key;

$this->value = $value;

$this->nextNode = $nextNode;

}

}

  $ht = new HashTable();

  $ht->insert('Bucket1','value1');

  $ht->insert('Bucket2','value2');

  $ht->insert('Bucket3','value3');

  echo $ht->find('Bucket1');

?>