常用hash算法

这个比较多，还有性能测评：

http://yuhuafx.blog.hexun.com/58369610_d.html

 

这个也不错，介绍非常全，非常详细：

 http://iaml.is-programmer.com/posts/7878.html

 

暴雪大大的~很有趣，三重哈希值验证存储地方：

http://opaque.blogbus.com/logs/30017835.html

 

一致性哈西算法，分布式计算可以用：

http://blog.youkuaiyun.com/sparkliang/archive/2010/02/02/5279393.aspx

 

 

 

 

times33的哈希算法，就是乘以33求散列：

static unsigned long int zend_inline_hash_func(const char *arKey, unsigned int nKeyLength) { register unsigned long int hash = 5381; /* variant with the hash unrolled eight times */ for (; nKeyLength >= 8; nKeyLength -= 8) { hash = ((hash << 5) + hash) + *arKey++; hash = ((hash << 5) + hash) + *arKey++; hash = ((hash << 5) + hash) + *arKey++; hash = ((hash << 5) + hash) + *arKey++; hash = ((hash << 5) + hash) + *arKey++; hash = ((hash << 5) + hash) + *arKey++; hash = ((hash << 5) + hash) + *arKey++; hash = ((hash << 5) + hash) + *arKey++; } switch (nKeyLength) { case 7: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */ case 6: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */ case 5: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */ case 4: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */ case 3: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */ case 2: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */ case 1: hash = ((hash << 5) + hash) + *arKey++; break; case 0: break; } return hash; }

 

 

简单的说就是规定一个初始值，然后对于每8bit数a，hash = hash*33 + a，因为字符串每个字符可以看成是usigned int(0-255)，所以最后求出来的值就是hash的结果了，是一个unsigned long类型的数。