资料:http://blog.youkuaiyun.com/liuben/article/details/5050697
1. 简单的方法:
unsigned int simple_hash(char *str)
{
register unsigned int hash;
register unsigned char *p;
for(hash = 0, p = (unsigned char *)str; *p ; p++)
hash = 31 * hash + *p;
return (hash & 0x7FFFFFFF);
}