各种hash函数

public class HashAlgorithms 
{ 
/** 
* 加法hash 
* @param key 字符串 
* @param prime 一个质数 
* @return hash结果 
*/ 
public static int additiveHash(String key, int prime) 
{ 
int hash, i; 
for (hash = key.length(), i = 0; i < key.length(); i++) 
hash += key.charAt(i); 
return (hash % prime); 
} 

/** 
* 旋转hash 
* @param key 输入字符串 
* @param prime 质数 
* @return hash值 
*/ 
public static int rotatingHash(String key, int prime) 
{ 
int hash, i; 
for (hash=key.length(), i=0; i<key.length(); ++i) 
hash = (hash<<4)^(hash>>28)^key.charAt(i); 
return (hash % prime); 
// return (hash ^ (hash>>10) ^ (hash>>20)); 
} 

// 替代： 
// 使用：hash = (hash ^ (hash>>10) ^ (hash>>20)) & mask; 
// 替代：hash %= prime; 


/** 
* MASK值，随便找一个值，最好是质数 
*/ 
static int M_MASK = 0x8765fed1; 
/** 
* 一次一个hash 
* @param key 输入字符串 
* @return 输出hash值 
*/ 
public static int oneByOneHash(String key) 
{ 
int hash, i; 
for (hash=0, i=0; i<key.length(); ++i) 
{ 
hash += key.charAt(i); 
hash += (hash << 10); 
hash ^= (hash >> 6); 
} 
hash += (hash << 3); 
hash ^= (hash >> 11); 
hash += (hash << 15); 
// return (hash & M_MASK); 
return hash; 
} 

/** 
* Bernstein‘s hash 
* @param key 输入字节数组 
* @param level 初始hash常量 
* @return 结果hash 
*/ 
public static int bernstein(String key) 
{ 
int hash = 0; 
int i; 
for (i=0; i<key.length(); ++i) hash = 33*hash + key.charAt(i); 
return hash; 
} 

// 
//// Pearson‘s Hash 
// char pearson(char[]key, ub4 len, char tab[256]) 
// { 
// char hash; 
// ub4 i; 
// for (hash=len, i=0; i<len; ++i) 
// hash=tab[hash^key[i]]; 
// return (hash); 
// } 

//// CRC Hashing，计算crc,具体代码见其他 
// ub4 crc(char *key, ub4 len, ub4 mask, ub4 tab[256]) 
// { 
// ub4 hash, i; 
// for (hash=len, i=0; i<len; ++i) 
// hash = (hash >> 8) ^ tab[(hash & 0xff) ^ key[i]]; 
// return (hash & mask); 
// } 

/** 
* Universal Hashing 
*/ 
public static int universal(char[]key, int mask, int[] tab) 
{ 
int hash = key.length, i, len = key.length; 
for (i=0; i<(len<<3); i+=8) 
{ 
char k = key[i>>3]; 
if ((k&0x01) == 0) hash ^= tab[i+0]; 
if ((k&0x02) == 0) hash ^= tab[i+1]; 
if ((k&0x04) == 0) hash ^= tab[i+2]; 
if ((k&0x08) == 0) hash ^= tab[i+3]; 
if ((k&0x10) == 0) hash ^= tab[i+4]; 
if ((k&0x20) == 0) hash ^= tab[i+5]; 
if ((k&0x40) == 0) hash ^= tab[i+6]; 
if ((k&0x80) == 0) hash ^= tab[i+7]; 
} 
return (hash & mask); 
} 

/** 
* Zobrist Hashing 
*/ 
public static int zobrist( char[] key,int mask, int[][] tab) 
{ 
int hash, i; 
for (hash=key.length, i=0; i<key.length; ++i) 
hash ^= tab[i][key[i]]; 
return (hash & mask); 
} 

// LOOKUP3 
// 见Bob Jenkins(3).c文件 

// 32位FNV算法 
static int M_SHIFT = 0; 
/** 
* 32位的FNV算法 
* @param data 数组 
* @return int值 
*/ 
public static int FNVHash(byte[] data) 
{ 
int hash = (int)2166136261L; 
for(byte b : data) 
hash = (hash * 16777619) ^ b; 
if (M_SHIFT == 0) 
return hash; 
return (hash ^ (hash >> M_SHIFT)) & M_MASK; 
} 
/** 
* 改进的32位FNV算法1 
* @param data 数组 
* @return int值 
*/ 
public static int FNVHash1(byte[] data) 
{ 
final int p = 16777619; 
int hash = (int)2166136261L; 
for(byte b:data) 
hash = (hash ^ b) * p; 
hash += hash << 13; 
hash ^= hash >> 7; 
hash += hash << 3; 
hash ^= hash >> 17; 
hash += hash << 5; 
return hash; 
} 
/** 
* 改进的32位FNV算法1 
* @param data 字符串 
* @return int值 
*/ 
public static int FNVHash1(String data) 
{ 
final int p = 16777619; 
int hash = (int)2166136261L; 
for(int i=0;i<data.length();i++) 
hash = (hash ^ data.charAt(i)) * p; 
hash += hash << 13; 
hash ^= hash >> 7; 
hash += hash << 3; 
hash ^= hash >> 17; 
hash += hash << 5; 
return hash; 
} 

/** 
* Thomas Wang的算法，整数hash 
*/ 
public static int intHash(int key) 
{ 
key += ~(key << 15); 
key ^= (key >>> 10); 
key += (key << 3); 
key ^= (key >>> 6); 
key += ~(key << 11); 
key ^= (key >>> 16); 
return key; 
} 
/** 
* RS算法hash 
* @param str 字符串 
*/ 
public static int RSHash(String str) 
{ 
int b = 378551; 
int a = 63689; 
int hash = 0; 

for(int i = 0; i < str.length(); i++) 
{ 
hash = hash * a + str.charAt(i); 
a = a * b; 
} 

return (hash & 0x7FFFFFFF); 
} 
/* End Of RS Hash Function */ 

/** 
* JS算法 
*/ 
public static int JSHash(String str) 
{ 
int hash = 1315423911; 

for(int i = 0; i < str.length(); i++) 
{ 
hash ^= ((hash << 5) + str.charAt(i) + (hash >> 2)); 
} 

return (hash & 0x7FFFFFFF); 
} 
/* End Of JS Hash Function */ 

/** 
* PJW算法 
*/ 
public static int PJWHash(String str) 
{ 
int BitsInUnsignedInt = 32; 
int ThreeQuarters = (BitsInUnsignedInt * 3) / 4; 
int OneEighth = BitsInUnsignedInt / 8; 
int HighBits = 0xFFFFFFFF << (BitsInUnsignedInt - OneEighth); 
int hash = 0; 
int test = 0; 

for(int i = 0; i < str.length();i++) 
{ 
hash = (hash << OneEighth) + str.charAt(i); 

if((test = hash & HighBits) != 0) 
{ 
hash = (( hash ^ (test >> ThreeQuarters)) & (~HighBits)); 
} 
} 

return (hash & 0x7FFFFFFF); 
} 
/* End Of P. J. Weinberger Hash Function */ 

/** 
* ELF算法 
*/ 
public static int ELFHash(String str) 
{ 
int hash = 0; 
int x = 0; 

for(int i = 0; i < str.length(); i++) 
{ 
hash = (hash << 4) + str.charAt(i); 
if((x = (int)(hash & 0xF0000000L)) != 0) 
{ 
hash ^= (x >> 24); 
hash &= ~x; 
} 
} 

return (hash & 0x7FFFFFFF); 
} 
/* End Of ELF Hash Function */ 

/** 
* BKDR算法 
*/ 
public static int BKDRHash(String str) 
{ 
int seed = 131; // 31 131 1313 13131 131313 etc.. 
int hash = 0; 

for(int i = 0; i < str.length(); i++) 
{ 
hash = (hash * seed) + str.charAt(i); 
} 

return (hash & 0x7FFFFFFF); 
} 
/* End Of BKDR Hash Function */ 

/** 
* SDBM算法 
*/ 
public static int SDBMHash(String str) 
{ 
int hash = 0; 

for(int i = 0; i < str.length(); i++) 
{ 
hash = str.charAt(i) + (hash << 6) + (hash << 16) - hash; 
} 

return (hash & 0x7FFFFFFF); 
} 
/* End Of SDBM Hash Function */ 

/** 
* DJB算法 
*/ 
public static int DJBHash(String str) 
{ 
int hash = 5381; 

for(int i = 0; i < str.length(); i++) 
{ 
hash = ((hash << 5) + hash) + str.charAt(i); 
} 

return (hash & 0x7FFFFFFF); 
} 
/* End Of DJB Hash Function */ 

/** 
* DEK算法 
*/ 
public static int DEKHash(String str) 
{ 
int hash = str.length(); 

for(int i = 0; i < str.length(); i++) 
{ 
hash = ((hash << 5) ^ (hash >> 27)) ^ str.charAt(i); 
} 

return (hash & 0x7FFFFFFF); 
} 

/** 
* ELF算法 
*/ 
public static int ELFHash(String str) 
{ 
    int hash = 0; 
    int x = 0; 

    for(int i = 0; i < str.length(); i++) 
    { 
        hash = (hash << 4) + str.charAt(i); 
        if((x = (int)(hash & 0xF0000000L)) != 0) 
        { 
            hash ^= (x >> 24); 
            hash &= ~x; 
        } 
    }
｝ 

glib质数表

static const gint prime_mod [] =
{
1, /* For 1 << 0 */
2,
3,
7,
13,
31,
61,
127,
251,
509,
1021,
2039,
4093,
8191,
16381,
32749,
65521, /* For 1 << 16 */
131071,
262139,
524287,
1048573,
2097143,
4194301,
8388593,
16777213,
33554393,
67108859,
134217689,
268435399,
536870909,
1073741789,
2147483647 /* For 1 << 31 */
};