常用Hash算法(C語言的簡單實(shí)現(xiàn))
更新時(shí)間：2016年09月25日 20:26:39 投稿：jingxian
下面小編就為大家?guī)硪黄Ｓ肏ash算法(C語言的簡單實(shí)現(xiàn))。小編覺得挺不錯(cuò)的，現(xiàn)在就分享給大家，也給大家做個(gè)參考。一起跟隨小編過來看看吧
如下所示：
#include "GeneralHashFunctions.h"
unsigned int RSHash(char* str, unsigned int len)
{
unsigned int b = 378551;
unsigned int a = 63689;
unsigned int hash = 0;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash = hash * a + (*str);
a = a * b;
}
return hash;
}
/* End Of RS Hash Function */
unsigned int JSHash(char* str, unsigned int len)
{
unsigned int hash = 1315423911;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash ^= ((hash << 5) + (*str) + (hash >> 2));
}
return hash;
}
/* End Of JS Hash Function */
unsigned int PJWHash(char* str, unsigned int len)
{
const unsigned int BitsInUnsignedInt = (unsigned int)(sizeof(unsigned int) * 8);
const unsigned int ThreeQuarters = (unsigned int)((BitsInUnsignedInt * 3) / 4);
const unsigned int OneEighth = (unsigned int)(BitsInUnsignedInt / 8);
const unsigned int HighBits = (unsigned int)(0xFFFFFFFF) << (BitsInUnsignedInt - OneEighth);
unsigned int hash = 0;
unsigned int test = 0;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash = (hash << OneEighth) + (*str);
if((test = hash & HighBits) != 0)
{
hash = (( hash ^ (test >> ThreeQuarters)) & (~HighBits));
}
}
return hash;
}
/* End Of P. J. Weinberger Hash Function */
unsigned int ELFHash(char* str, unsigned int len)
{
unsigned int hash = 0;
unsigned int x = 0;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash = (hash << 4) + (*str);
if((x = hash & 0xF0000000L) != 0)
{
hash ^= (x >> 24);
}
hash &= ~x;
}
return hash;
}
/* End Of ELF Hash Function */
unsigned int BKDRHash(char* str, unsigned int len)
{
unsigned int seed = 131; /* 31 131 1313 13131 131313 etc.. */
unsigned int hash = 0;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash = (hash * seed) + (*str);
}
return hash;
}
/* End Of BKDR Hash Function */
unsigned int SDBMHash(char* str, unsigned int len)
{
unsigned int hash = 0;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash = (*str) + (hash << 6) + (hash << 16) - hash;
}
return hash;
}
/* End Of SDBM Hash Function */
unsigned int DJBHash(char* str, unsigned int len)
{
unsigned int hash = 5381;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash = ((hash << 5) + hash) + (*str);
}
return hash;
}
/* End Of DJB Hash Function */
unsigned int DEKHash(char* str, unsigned int len)
{
unsigned int hash = len;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash = ((hash << 5) ^ (hash >> 27)) ^ (*str);
}
return hash;
}
/* End Of DEK Hash Function */
unsigned int BPHash(char* str, unsigned int len)
{
unsigned int hash = 0;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash = hash << 7 ^ (*str);
}
return hash;
}
/* End Of BP Hash Function */
unsigned int FNVHash(char* str, unsigned int len)
{
const unsigned int fnv_prime = 0x811C9DC5;
unsigned int hash = 0;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash *= fnv_prime;
hash ^= (*str);
}
return hash;
}
/* End Of FNV Hash Function */
unsigned int APHash(char* str, unsigned int len)
{
unsigned int hash = 0xAAAAAAAA;
unsigned int i = 0;
for(i = 0; i < len; str++, i++)
{
hash ^= ((i & 1) == 0) ? ( (hash << 7) ^ (*str) * (hash >> 3)) :
(~((hash << 11) + ((*str) ^ (hash >> 5))));
}
return hash;
}
/* End Of AP Hash Function */
以上就是小編為大家?guī)淼某Ｓ肏ash算法(C語言的簡單實(shí)現(xiàn))的全部內(nèi)容了，希望對大家有所幫助，多多支持腳本之家~
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