hash算法
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/** * 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;}/** * 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;}}
