JAVA HASH算法

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本篇文章主要介绍了"JAVA HASH算法",主要涉及到JAVA HASH算法方面的内容,对于JAVA HASH算法感兴趣的同学可以参考一下。

/** * Hash算法大全<br> * 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 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);     }     /**//* 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) ? ( (hash << 7) ^ str.charAt(i) ^ (hash >> 3)) :         (~((hash << 11) ^ str.charAt(i) ^ (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;     } }

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