字符串哈希函数 【ZZ http://www.byvoid.com/blog/string-hash-compare/】

 1 unsigned int BKDRHash(char *str)
 2 {
 3     unsigned int seed = 131; // 31 131 1313 13131 131313 etc..
 4     unsigned int hash = 0;
 5  
 6     while (*str)
 7     {
 8         hash = hash * seed + (*str++);
 9     }
10  
11     return (hash & 0x7FFFFFFF);
12 }

 

 1 unsigned int APHash(char *str)
 2 {
 3     unsigned int hash = 0;
 4     int i;
 5  
 6     for (i=0; *str; i++)
 7     {
 8         if ((i & 1) == 0)
 9         {
10             hash ^= ((hash << 7) ^ (*str++) ^ (hash >> 3));
11         }
12         else
13         {
14             hash ^= (~((hash << 11) ^ (*str++) ^ (hash >> 5)));
15         }
16     }
17  
18     return (hash & 0x7FFFFFFF);
19 }