当前位置: 首页 > Java > 正文

Hash算法Java

关键字:
1 星2 星3 星4 星5 星 (暂无评分)
Loading ... Loading ...
baidu_share

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:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
package com.xq.test;
 
/**
 * 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;
	}
 
	public static void main(String[] args){
		System.out.println(java("192.168.0.1")%1000);
		System.out.println(java("192.168.0.2")%1000);
		System.out.println(java("112.118.0.2")%1000);
	}
}

本文固定链接: http://www.chepoo.com/java-hash-algorithm.html | IT技术精华网

Hash算法Java:等您坐沙发呢!

发表评论