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49 #include <rte_byteorder.h>
51 /* jhash.h: Jenkins hash support.
53 * Copyright (C) 2006 Bob Jenkins (bob_jenkins@burtleburtle.net)
55 * http://burtleburtle.net/bob/hash/
57 * These are the credits from Bob's sources:
59 * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
61 * These are functions for producing 32-bit hashes for hash table lookup.
62 * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
63 * are externally useful functions. Routines to test the hash are included
64 * if SELF_TEST is defined. You can use this free for any purpose. It's in
65 * the public domain. It has no warranty.
70 #define rot(x, k) (((x) << (k)) | ((x) >> (32-(k))))
72 /** @internal Internal function. NOTE: Arguments are modified. */
73 #define __rte_jhash_mix(a, b, c) do { \
74 a -= c; a ^= rot(c, 4); c += b; \
75 b -= a; b ^= rot(a, 6); a += c; \
76 c -= b; c ^= rot(b, 8); b += a; \
77 a -= c; a ^= rot(c, 16); c += b; \
78 b -= a; b ^= rot(a, 19); a += c; \
79 c -= b; c ^= rot(b, 4); b += a; \
82 #define __rte_jhash_final(a, b, c) do { \
83 c ^= b; c -= rot(b, 14); \
84 a ^= c; a -= rot(c, 11); \
85 b ^= a; b -= rot(a, 25); \
86 c ^= b; c -= rot(b, 16); \
87 a ^= c; a -= rot(c, 4); \
88 b ^= a; b -= rot(a, 14); \
89 c ^= b; c -= rot(b, 24); \
92 /** The golden ratio: an arbitrary value. */
93 #define RTE_JHASH_GOLDEN_RATIO 0xdeadbeef
95 #if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
96 #define BIT_SHIFT(x, y, k) (((x) >> (k)) | ((uint64_t)(y) << (32-(k))))
98 #define BIT_SHIFT(x, y, k) (((uint64_t)(x) << (k)) | ((y) >> (32-(k))))
101 #define LOWER8b_MASK rte_le_to_cpu_32(0xff)
102 #define LOWER16b_MASK rte_le_to_cpu_32(0xffff)
103 #define LOWER24b_MASK rte_le_to_cpu_32(0xffffff)
106 __rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc,
107 uint32_t *pb, unsigned check_align)
111 /* Set up the internal state */
112 a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + *pc;
116 * Check key alignment. For x86 architecture, first case is always optimal
117 * If check_align is not set, first case will be used
119 #if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32)
120 const uint32_t *k = key;
121 const uint32_t s = 0;
123 const uint32_t *k = (uint32_t *)(uintptr_t)key & (uintptr_t)~3);
124 const uint32_t s = ((uintptr_t)key & 3) * CHAR_BIT;
126 if (!check_align || s == 0) {
127 while (length > 12) {
132 __rte_jhash_mix(a, b, c);
140 c += k[2]; b += k[1]; a += k[0]; break;
142 c += k[2] & LOWER24b_MASK; b += k[1]; a += k[0]; break;
144 c += k[2] & LOWER16b_MASK; b += k[1]; a += k[0]; break;
146 c += k[2] & LOWER8b_MASK; b += k[1]; a += k[0]; break;
148 b += k[1]; a += k[0]; break;
150 b += k[1] & LOWER24b_MASK; a += k[0]; break;
152 b += k[1] & LOWER16b_MASK; a += k[0]; break;
154 b += k[1] & LOWER8b_MASK; a += k[0]; break;
158 a += k[0] & LOWER24b_MASK; break;
160 a += k[0] & LOWER16b_MASK; break;
162 a += k[0] & LOWER8b_MASK; break;
163 /* zero length strings require no mixing */
170 /* all but the last block: affect some 32 bits of (a, b, c) */
171 while (length > 12) {
172 a += BIT_SHIFT(k[0], k[1], s);
173 b += BIT_SHIFT(k[1], k[2], s);
174 c += BIT_SHIFT(k[2], k[3], s);
175 __rte_jhash_mix(a, b, c);
181 /* last block: affect all 32 bits of (c) */
184 a += BIT_SHIFT(k[0], k[1], s);
185 b += BIT_SHIFT(k[1], k[2], s);
186 c += BIT_SHIFT(k[2], k[3], s);
189 a += BIT_SHIFT(k[0], k[1], s);
190 b += BIT_SHIFT(k[1], k[2], s);
191 c += BIT_SHIFT(k[2], k[3], s) & LOWER24b_MASK;
194 a += BIT_SHIFT(k[0], k[1], s);
195 b += BIT_SHIFT(k[1], k[2], s);
196 c += BIT_SHIFT(k[2], k[3], s) & LOWER16b_MASK;
199 a += BIT_SHIFT(k[0], k[1], s);
200 b += BIT_SHIFT(k[1], k[2], s);
201 c += BIT_SHIFT(k[2], k[3], s) & LOWER8b_MASK;
204 a += BIT_SHIFT(k[0], k[1], s);
205 b += BIT_SHIFT(k[1], k[2], s);
208 a += BIT_SHIFT(k[0], k[1], s);
209 b += BIT_SHIFT(k[1], k[2], s) & LOWER24b_MASK;
212 a += BIT_SHIFT(k[0], k[1], s);
213 b += BIT_SHIFT(k[1], k[2], s) & LOWER16b_MASK;
216 a += BIT_SHIFT(k[0], k[1], s);
217 b += BIT_SHIFT(k[1], k[2], s) & LOWER8b_MASK;
220 a += BIT_SHIFT(k[0], k[1], s);
223 a += BIT_SHIFT(k[0], k[1], s) & LOWER24b_MASK;
226 a += BIT_SHIFT(k[0], k[1], s) & LOWER16b_MASK;
229 a += BIT_SHIFT(k[0], k[1], s) & LOWER8b_MASK;
231 /* zero length strings require no mixing */
239 __rte_jhash_final(a, b, c);
246 * Same as rte_jhash, but takes two seeds and return two uint32_ts.
247 * pc and pb must be non-null, and *pc and *pb must both be initialized
248 * with seeds. If you pass in (*pb)=0, the output (*pc) will be
249 * the same as the return value from rte_jhash.
252 * Key to calculate hash of.
254 * Length of key in bytes.
256 * IN: seed OUT: primary hash value.
258 * IN: second seed OUT: secondary hash value.
261 rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc, uint32_t *pb)
263 __rte_jhash_2hashes(key, length, pc, pb, 1);
267 * Same as rte_jhash2, but takes two seeds and return two uint32_ts.
268 * pc and pb must be non-null, and *pc and *pb must both be initialized
269 * with seeds. If you pass in (*pb)=0, the output (*pc) will be
270 * the same as the return value from rte_jhash2.
273 * Key to calculate hash of.
275 * Length of key in units of 4 bytes.
277 * IN: seed OUT: primary hash value.
279 * IN: second seed OUT: secondary hash value.
282 rte_jhash2_2hashes(const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t *pb)
284 __rte_jhash_2hashes((const void *) k, (length << 2), pc, pb, 0);
288 * The most generic version, hashes an arbitrary sequence
289 * of bytes. No alignment or length assumptions are made about
293 * Key to calculate hash of.
295 * Length of key in bytes.
297 * Initialising value of hash.
299 * Calculated hash value.
301 static inline uint32_t
302 rte_jhash(const void *key, uint32_t length, uint32_t initval)
304 uint32_t initval2 = 0;
306 rte_jhash_2hashes(key, length, &initval, &initval2);
312 * A special optimized version that handles 1 or more of uint32_ts.
313 * The length parameter here is the number of uint32_ts in the key.
316 * Key to calculate hash of.
318 * Length of key in units of 4 bytes.
320 * Initialising value of hash.
322 * Calculated hash value.
324 static inline uint32_t
325 rte_jhash2(const uint32_t *k, uint32_t length, uint32_t initval)
327 uint32_t initval2 = 0;
329 rte_jhash2_2hashes(k, length, &initval, &initval2);
334 static inline uint32_t
335 __rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
337 a += RTE_JHASH_GOLDEN_RATIO + initval;
338 b += RTE_JHASH_GOLDEN_RATIO + initval;
339 c += RTE_JHASH_GOLDEN_RATIO + initval;
341 __rte_jhash_final(a, b, c);
347 * A special ultra-optimized versions that knows it is hashing exactly
351 * First word to calcuate hash of.
353 * Second word to calcuate hash of.
355 * Third word to calcuate hash of.
357 * Initialising value of hash.
359 * Calculated hash value.
361 static inline uint32_t
362 rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
364 return __rte_jhash_3words(a + 12, b + 12, c + 12, initval);
368 * A special ultra-optimized versions that knows it is hashing exactly
372 * First word to calcuate hash of.
374 * Second word to calcuate hash of.
376 * Initialising value of hash.
378 * Calculated hash value.
380 static inline uint32_t
381 rte_jhash_2words(uint32_t a, uint32_t b, uint32_t initval)
383 return __rte_jhash_3words(a + 8, b + 8, 8, initval);
387 * A special ultra-optimized versions that knows it is hashing exactly
391 * Word to calcuate hash of.
393 * Initialising value of hash.
395 * Calculated hash value.
397 static inline uint32_t
398 rte_jhash_1word(uint32_t a, uint32_t initval)
400 return __rte_jhash_3words(a + 4, 4, 4, initval);
407 #endif /* _RTE_JHASH_H */