Hash算法大全(java实现).doc

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1、Hash算法大全(java实现）java view plaincopy/* * Hash算法大全 * 推荐使用FNV1算法 * algorithm None * author Goodzzp 2006-11-20 * lastEdit Goodzzp 2006-11-20 * editDetail Create */ 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

2、 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; ikey.length(); +i)

3、hash = (hash28)key.charAt(i); return (hash % prime); / return (hash (hash10) (hash20); / 替代： / 使用：hash = (hash (hash10) (hash20) & 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(S

4、tring key) int hash, i; for (hash=0, i=0; ikey.length(); +i) hash += key.charAt(i); hash += (hash 6); hash += (hash 11); hash += (hash 15); / return (hash & M_MASK); return hash; /* * Bernsteins 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)

5、 int hash = 0; int i; for (i=0; ikey.length(); +i) hash = 33*hash + key.charAt(i); return hash; / / Pearsons Hash / char pearson(charkey, ub4 len, char tab256) / / char hash; / ub4 i; / for (hash=len, i=0; ilen; +i) / hash=tabhashkeyi; / return (hash); / / CRC Hashing，计算crc,具体代码见其他 / ub4 crc(char *k

6、ey, ub4 len, ub4 mask, ub4 tab256) / / ub4 hash, i; / for (hash=len, i=0; i 8) tab(hash & 0xff) keyi; / return (hash & mask); / /* * Universal Hashing */ public static int universal(charkey, int mask, int tab) int hash = key.length, i, len = key.length; for (i=0; i(len3; if (k&0x01) = 0) hash = tabi

7、+0; if (k&0x02) = 0) hash = tabi+1; if (k&0x04) = 0) hash = tabi+2; if (k&0x08) = 0) hash = tabi+3; if (k&0x10) = 0) hash = tabi+4; if (k&0x20) = 0) hash = tabi+5; if (k&0x40) = 0) hash = tabi+6; if (k&0x80) = 0) hash = tabi+7; return (hash & mask); /* * Zobrist Hashing */ public static int zobrist(

8、 char key,int mask, int tab) int hash, i; for (hash=key.length, i=0; i 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 = ; int hash = (int)L; for(byte b:data) hash = (hash b) * p; hash += hash 7; hash += hash 17; hash += hash 5;

9、 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 = ; int hash = (int)L; for(int i=0;idata.length();i+) hash = (hash data.charAt(i) * p; hash += hash 7; hash += hash 17; hash += hash 5; return hash; /* * Thomas Wang的算法，整数hash */ pub

10、lic static int intHash(int key) key += (key 10); key += (key 6); key += (key 16); return key; /* * RS算法hash * param str 字符串 */ public static int RSHash(String str) int b = ; 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 & 0x7

11、FFFFFFF); /* End Of RS Hash Function */ /* * JS算法 */ public static int JSHash(String str) int hash = ; for(int i = 0; i str.length(); i+) hash = (hash 2); return (hash & 0x7FFFFFFF); /* End Of JS Hash Function */ /* * PJW算法 */ public static int PJWHash(String str) int BitsInUnsignedInt = 32; int Thr

12、eeQuarters = (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 ThreeQuarters) & (HighBits); return (hash & 0x7FFFFFFF); /* End Of P. J. Weinberger H

13、ash 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 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

14、13131 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

15、 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 st

16、atic int DEKHash(String str) int hash = str.length(); for(int i = 0; i str.length(); i+) hash = (hash 27) str.charAt(i); return (hash & 0x7FFFFFFF); /* End Of DEK Hash Function */ /* * AP算法 */ public static int APHash(String str) int hash = 0; for(int i = 0; i str.length(); i+) hash = (i & 1) = 0) ?

17、 ( (hash 3) : (hash 5); / return (hash & 0x7FFFFFFF); return hash; /* End Of AP Hash Function */ /* * JAVA自己带的算法 */ public static int java(String str) int h = 0; int off = 0; int len = str.length(); for (int i = 0; i len; i+) h = 31 * h + str.charAt(off+); return h; /* * 混合hash算法，输出64位的值 */ public static long mixHash(String str) long hash = str.hashCode(); hash = 32; hash |= FNVHash1(str); return hash; Hash算法有很多很多种类。具体的可以参考之前我写的Hash算法的一些分析。本处给大家提供一个集合了很多使用的Hash算法的类，应该可以满足不少人的需要的：