见代码:
unsigned int hash_BPHash(unsigned char *str){
unsigned int hash = 0;
while(*str){
hash = (hash << 7) ^ (*str++);
}
return hash;
}
unsigned int hash_FNVHash(unsigned char *str){
unsigned int hash = 0;
while(*str){
hash = (hash * 0x811C9DC5) ^ (*str++);
}
return hash;
}
unsigned int hash_BKDRHash(unsigned char *str){
unsigned int hash = 0;
while(*str){
hash = (hash * 131) + (*str++); // 31 131 1313 13131 131313 etc...
}
return hash;
}
unsigned int hash_DJBHash(unsigned char *str){
unsigned int hash = 5381;
while(*str){
hash += ((hash << 5) + (*str++));
}
return hash;
}
unsigned int hash_JSHash(unsigned char *str){
unsigned int hash = 1315423911;
while(*str){
hash ^= ((hash << 5) + (hash >> 2) + (*str++));
}
return hash;
}
unsigned int hash_DEKHash(unsigned char *str){
unsigned int hash = strlen(str);
while(*str){
hash = ((hash << 5) ^ (hash >> 27)) ^ (*str++);
}
return hash;
}
unsigned int hash_SDBMHash(unsigned char *str){
unsigned int hash = 0;
while(*str){
hash = (hash << 6) + (hash << 16) + (*str++) - hash;
}
return hash;
}
unsigned int hash_RSHash(unsigned char *str){
unsigned int a = 63689;
unsigned int hash = 0;
while(*str){
hash = hash * a + (*str++);
a *= 378551;
}
return hash;
}
unsigned int hash_APHash(unsigned char *str){
unsigned int hash = 0; //0x00000000, 0xAAAAAAAA
unsigned int flag = 0;
while(*str){
if(flag&1){
hash ^= (~((hash << 11) ^ (*str++) ^ (hash >> 5)));
}
else{
hash ^= ((hash << 7) ^ (*str++) ^ (hash >> 3));
}
flag++;
}
return hash;
}
unsigned int hash_PJWHash(unsigned char *str){
unsigned int hash = 0;
unsigned int test = 0;
while(*str){
hash = (hash << 4) + (*str++);
if((test = hash & 0xF0000000) != 0){
hash = ((hash ^ (test >> 24)) & 0x0FFFFFFF);
}
}
return hash;
}
unsigned int hash_ELFHash(unsigned char *str){
unsigned int hash = 0;
unsigned int test = 0;
while(*str){
hash = (hash << 4) + (*str++);
if((test = hash & 0xF0000000) != 0){
hash = ((hash ^ (test >> 24)) & (~test));
}
}
return hash;
}
另外收集了一个查表法的CRC32校验算法,也可用于字符串哈希,见 《一种查表法实现的CRC32校验算法》 这篇笔记。
记于 2019-02-23