aboutsummaryrefslogtreecommitdiffstats
path: root/lib/librte_hash/rte_jhash.h
blob: 207478c2823dd703593aaf11271e4f5f0b174946 (plain)
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
/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _RTE_JHASH_H
#define _RTE_JHASH_H

/**
 * @file
 *
 * jhash functions.
 */

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include <string.h>
#include <limits.h>

#include <rte_log.h>
#include <rte_byteorder.h>

/* jhash.h: Jenkins hash support.
 *
 * Copyright (C) 2006 Bob Jenkins (bob_jenkins@burtleburtle.net)
 *
 * http://burtleburtle.net/bob/hash/
 *
 * These are the credits from Bob's sources:
 *
 * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
 *
 * These are functions for producing 32-bit hashes for hash table lookup.
 * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
 * are externally useful functions.  Routines to test the hash are included
 * if SELF_TEST is defined.  You can use this free for any purpose.  It's in
 * the public domain.  It has no warranty.
 *
 * $FreeBSD$
 */

#define rot(x, k) (((x) << (k)) | ((x) >> (32-(k))))

/** @internal Internal function. NOTE: Arguments are modified. */
#define __rte_jhash_mix(a, b, c) do { \
	a -= c; a ^= rot(c, 4); c += b; \
	b -= a; b ^= rot(a, 6); a += c; \
	c -= b; c ^= rot(b, 8); b += a; \
	a -= c; a ^= rot(c, 16); c += b; \
	b -= a; b ^= rot(a, 19); a += c; \
	c -= b; c ^= rot(b, 4); b += a; \
} while (0)

#define __rte_jhash_final(a, b, c) do { \
	c ^= b; c -= rot(b, 14); \
	a ^= c; a -= rot(c, 11); \
	b ^= a; b -= rot(a, 25); \
	c ^= b; c -= rot(b, 16); \
	a ^= c; a -= rot(c, 4);  \
	b ^= a; b -= rot(a, 14); \
	c ^= b; c -= rot(b, 24); \
} while (0)

/** The golden ratio: an arbitrary value. */
#define RTE_JHASH_GOLDEN_RATIO      0xdeadbeef

#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
#define BIT_SHIFT(x, y, k) (((x) >> (k)) | ((uint64_t)(y) << (32-(k))))
#else
#define BIT_SHIFT(x, y, k) (((uint64_t)(x) << (k)) | ((y) >> (32-(k))))
#endif

#define LOWER8b_MASK rte_le_to_cpu_32(0xff)
#define LOWER16b_MASK rte_le_to_cpu_32(0xffff)
#define LOWER24b_MASK rte_le_to_cpu_32(0xffffff)

static inline void
__rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc,
		uint32_t *pb, unsigned check_align)
{
	uint32_t a, b, c;

	/* Set up the internal state */
	a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + *pc;
	c += *pb;

	/*
	 * Check key alignment. For x86 architecture, first case is always optimal
	 * If check_align is not set, first case will be used
	 */
#if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32)
	const uint32_t *k = (const uint32_t *)key;
	const uint32_t s = 0;
#else
	const uint32_t *k = (uint32_t *)((uintptr_t)key & (uintptr_t)~3);
	const uint32_t s = ((uintptr_t)key & 3) * CHAR_BIT;
#endif
	if (!check_align || s == 0) {
		while (length > 12) {
			a += k[0];
			b += k[1];
			c += k[2];

			__rte_jhash_mix(a, b, c);

			k += 3;
			length -= 12;
		}

		switch (length) {
		case 12:
			c += k[2]; b += k[1]; a += k[0]; break;
		case 11:
			c += k[2] & LOWER24b_MASK; b += k[1]; a += k[0]; break;
		case 10:
			c += k[2] & LOWER16b_MASK; b += k[1]; a += k[0]; break;
		case 9:
			c += k[2] & LOWER8b_MASK; b += k[1]; a += k[0]; break;
		case 8:
			b += k[1]; a += k[0]; break;
		case 7:
			b += k[1] & LOWER24b_MASK; a += k[0]; break;
		case 6:
			b += k[1] & LOWER16b_MASK; a += k[0]; break;
		case 5:
			b += k[1] & LOWER8b_MASK; a += k[0]; break;
		case 4:
			a += k[0]; break;
		case 3:
			a += k[0] & LOWER24b_MASK; break;
		case 2:
			a += k[0] & LOWER16b_MASK; break;
		case 1:
			a += k[0] & LOWER8b_MASK; break;
		/* zero length strings require no mixing */
		case 0:
			*pc = c;
			*pb = b;
			return;
		};
	} else {
		/* all but the last block: affect some 32 bits of (a, b, c) */
		while (length > 12) {
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s);
			c += BIT_SHIFT(k[2], k[3], s);
			__rte_jhash_mix(a, b, c);

			k += 3;
			length -= 12;
		}

		/* last block: affect all 32 bits of (c) */
		switch (length) {
		case 12:
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s);
			c += BIT_SHIFT(k[2], k[3], s);
			break;
		case 11:
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s);
			c += BIT_SHIFT(k[2], k[3], s) & LOWER24b_MASK;
			break;
		case 10:
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s);
			c += BIT_SHIFT(k[2], k[3], s) & LOWER16b_MASK;
			break;
		case 9:
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s);
			c += BIT_SHIFT(k[2], k[3], s) & LOWER8b_MASK;
			break;
		case 8:
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s);
			break;
		case 7:
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s) & LOWER24b_MASK;
			break;
		case 6:
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s) & LOWER16b_MASK;
			break;
		case 5:
			a += BIT_SHIFT(k[0], k[1], s);
			b += BIT_SHIFT(k[1], k[2], s) & LOWER8b_MASK;
			break;
		case 4:
			a += BIT_SHIFT(k[0], k[1], s);
			break;
		case 3:
			a += BIT_SHIFT(k[0], k[1], s) & LOWER24b_MASK;
			break;
		case 2:
			a += BIT_SHIFT(k[0], k[1], s) & LOWER16b_MASK;
			break;
		case 1:
			a += BIT_SHIFT(k[0], k[1], s) & LOWER8b_MASK;
			break;
		/* zero length strings require no mixing */
		case 0:
			*pc = c;
			*pb = b;
			return;
		}
	}

	__rte_jhash_final(a, b, c);

	*pc = c;
	*pb = b;
}

/**
 * Same as rte_jhash, but takes two seeds and return two uint32_ts.
 * pc and pb must be non-null, and *pc and *pb must both be initialized
 * with seeds. If you pass in (*pb)=0, the output (*pc) will be
 * the same as the return value from rte_jhash.
 *
 * @param key
 *   Key to calculate hash of.
 * @param length
 *   Length of key in bytes.
 * @param pc
 *   IN: seed OUT: primary hash value.
 * @param pb
 *   IN: second seed OUT: secondary hash value.
 */
static inline void
rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc, uint32_t *pb)
{
	__rte_jhash_2hashes(key, length, pc, pb, 1);
}

/**
 * Same as rte_jhash_32b, but takes two seeds and return two uint32_ts.
 * pc and pb must be non-null, and *pc and *pb must both be initialized
 * with seeds. If you pass in (*pb)=0, the output (*pc) will be
 * the same as the return value from rte_jhash_32b.
 *
 * @param k
 *   Key to calculate hash of.
 * @param length
 *   Length of key in units of 4 bytes.
 * @param pc
 *   IN: seed OUT: primary hash value.
 * @param pb
 *   IN: second seed OUT: secondary hash value.
 */
static inline void
rte_jhash_32b_2hashes(const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t *pb)
{
	__rte_jhash_2hashes((const void *) k, (length << 2), pc, pb, 0);
}

/**
 * The most generic version, hashes an arbitrary sequence
 * of bytes.  No alignment or length assumptions are made about
 * the input key.
 *
 * @param key
 *   Key to calculate hash of.
 * @param length
 *   Length of key in bytes.
 * @param initval
 *   Initialising value of hash.
 * @return
 *   Calculated hash value.
 */
static inline uint32_t
rte_jhash(const void *key, uint32_t length, uint32_t initval)
{
	uint32_t initval2 = 0;

	rte_jhash_2hashes(key, length, &initval, &initval2);

	return initval;
}

/**
 * A special optimized version that handles 1 or more of uint32_ts.
 * The length parameter here is the number of uint32_ts in the key.
 *
 * @param k
 *   Key to calculate hash of.
 * @param length
 *   Length of key in units of 4 bytes.
 * @param initval
 *   Initialising value of hash.
 * @return
 *   Calculated hash value.
 */
static inline uint32_t
rte_jhash_32b(const uint32_t *k, uint32_t length, uint32_t initval)
{
	uint32_t initval2 = 0;

	rte_jhash_32b_2hashes(k, length, &initval, &initval2);

	return initval;
}

static inline uint32_t
__rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
{
	a += RTE_JHASH_GOLDEN_RATIO + initval;
	b += RTE_JHASH_GOLDEN_RATIO + initval;
	c += RTE_JHASH_GOLDEN_RATIO + initval;

	__rte_jhash_final(a, b, c);

	return c;
}

/**
 * A special ultra-optimized versions that knows it is hashing exactly
 * 3 words.
 *
 * @param a
 *   First word to calculate hash of.
 * @param b
 *   Second word to calculate hash of.
 * @param c
 *   Third word to calculate hash of.
 * @param initval
 *   Initialising value of hash.
 * @return
 *   Calculated hash value.
 */
static inline uint32_t
rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
{
	return __rte_jhash_3words(a + 12, b + 12, c + 12, initval);
}

/**
 * A special ultra-optimized versions that knows it is hashing exactly
 * 2 words.
 *
 * @param a
 *   First word to calculate hash of.
 * @param b
 *   Second word to calculate hash of.
 * @param initval
 *   Initialising value of hash.
 * @return
 *   Calculated hash value.
 */
static inline uint32_t
rte_jhash_2words(uint32_t a, uint32_t b, uint32_t initval)
{
	return __rte_jhash_3words(a + 8, b + 8, 8, initval);
}

/**
 * A special ultra-optimized versions that knows it is hashing exactly
 * 1 word.
 *
 * @param a
 *   Word to calculate hash of.
 * @param initval
 *   Initialising value of hash.
 * @return
 *   Calculated hash value.
 */
static inline uint32_t
rte_jhash_1word(uint32_t a, uint32_t initval)
{
	return __rte_jhash_3words(a + 4, 4, 4, initval);
}

#ifdef __cplusplus
}
#endif

#endif /* _RTE_JHASH_H */