亿级数据判断 bitmap-布隆过滤器

$bitmap = 0b11101010;
$goodsId = 3;
$bitToNum = 1 << $goodsId;//算出这个数字的二进制位数
echo "goodsId 2的二进制:" . decbin($bitToNum), PHP_EOL;
$tempNum = $bitmap & $bitToNum;
echo "位运算结果:" . decbin($tempNum), PHP_EOL;
if ($tempNum != $bitToNum) {
    echo "商品id:{$goodsId}不存在\\n";
}else{
    echo "商品id:{$goodsId}存在\\n";
}

<?php
/**
 * Created by PhpStorm.
 * User: xdd
 * Date: 2020/9/21
 * Time: 10:23
 */
/**
 * Created by PhpStorm.
 * User: apple
 * Date: 2020-04-30
 * Time: 14:25
 */
class BloomFilter
{
    //由于php的int为64位,如果要存储10亿,或者更大的数据,需要通过多个int数组实现
    protected $bitmap = \[\];
    //一个int,只能表示0-64的数字
    //10亿的数字
    protected $maxNum = 1 << 30;
    function add($key)
    {
        $hash = $this->hash($key);
        $bitmapKey = $this->getBitmapKey($hash);
        if (isset($this->bitmap\[$bitmapKey\])) {
            //如果已经添加了这个数组,则直接与运算将数据加上
            $this->bitmap\[$bitmapKey\] = $this->bitmap\[$bitmapKey\] | (1 << ($hash % 64));
        } else {
            $this->bitmap\[$bitmapKey\] = 1 << ($hash % 64);
        }
        return $hash;
    }
    function get($key)
    {
        $hash = $this->hash($key);
        $bitmapKey = $this->getBitmapKey($hash);
        if (isset($this->bitmap\[$bitmapKey\])) {
            $bitToNum = 1 << ($hash % 64);//算出这个数字的二进制位数
            $tempNum = $this->bitmap\[$bitmapKey\] & $bitToNum;
            if ($tempNum != $bitToNum) {
                return false;
            }
            return true;
        } else {
            return false;
        }
    }
    function hash($key)
    {
        $hash = crc32($key);
        //time33返回的数据是0-2^31,目前我们的设想是只存储2^30,所以取余
        $hash = $hash % $this->maxNum;
        return $hash;
    }
    function getBitmapKey($data)
    {
        $key = intval($data / 64);
        return $key;
    }
}
$bloomFilter = new BloomFilter();
$str = "测试1234";
$hash = $bloomFilter->add($str);
var_dump($bloomFilter->get($str));
var_dump($bloomFilter->get('213312'));