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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 * The most generic version, hashes an arbitrary sequence
107 * of bytes. No alignment or length assumptions are made about
111 * Key to calculate hash of.
113 * Length of key in bytes.
115 * Initialising value of hash.
117 * Calculated hash value.
119 static inline uint32_t
120 rte_jhash(const void *key, uint32_t length, uint32_t initval)
124 /* Set up the internal state */
125 a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + initval;
127 /* Check key alignment. For x86 architecture, first case is always optimal */
128 #if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32)
129 const uint32_t *k = key;
130 const uint32_t s = 0;
132 const uint32_t *k = (uint32_t *)(uintptr_t)key & (uintptr_t)~3);
133 const uint32_t s = ((uintptr_t)key & 3) * CHAR_BIT;
137 while (length > 12) {
142 __rte_jhash_mix(a, b, c);
150 c += k[2]; b += k[1]; a += k[0]; break;
152 c += k[2] & LOWER24b_MASK; b += k[1]; a += k[0]; break;
154 c += k[2] & LOWER16b_MASK; b += k[1]; a += k[0]; break;
156 c += k[2] & LOWER8b_MASK; b += k[1]; a += k[0]; break;
158 b += k[1]; a += k[0]; break;
160 b += k[1] & LOWER24b_MASK; a += k[0]; break;
162 b += k[1] & LOWER16b_MASK; a += k[0]; break;
164 b += k[1] & LOWER8b_MASK; a += k[0]; break;
168 a += k[0] & LOWER24b_MASK; break;
170 a += k[0] & LOWER16b_MASK; break;
172 a += k[0] & LOWER8b_MASK; break;
173 /* zero length strings require no mixing */
178 /* all but the last block: affect some 32 bits of (a, b, c) */
179 while (length > 12) {
180 a += BIT_SHIFT(k[0], k[1], s);
181 b += BIT_SHIFT(k[1], k[2], s);
182 c += BIT_SHIFT(k[2], k[3], s);
183 __rte_jhash_mix(a, b, c);
189 /* last block: affect all 32 bits of (c) */
192 a += BIT_SHIFT(k[0], k[1], s);
193 b += BIT_SHIFT(k[1], k[2], s);
194 c += BIT_SHIFT(k[2], k[3], s);
197 a += BIT_SHIFT(k[0], k[1], s);
198 b += BIT_SHIFT(k[1], k[2], s);
199 c += BIT_SHIFT(k[2], k[3], s) & LOWER24b_MASK;
202 a += BIT_SHIFT(k[0], k[1], s);
203 b += BIT_SHIFT(k[1], k[2], s);
204 c += BIT_SHIFT(k[2], k[3], s) & LOWER16b_MASK;
207 a += BIT_SHIFT(k[0], k[1], s);
208 b += BIT_SHIFT(k[1], k[2], s);
209 c += BIT_SHIFT(k[2], k[3], s) & LOWER8b_MASK;
212 a += BIT_SHIFT(k[0], k[1], s);
213 b += BIT_SHIFT(k[1], k[2], s);
216 a += BIT_SHIFT(k[0], k[1], s);
217 b += BIT_SHIFT(k[1], k[2], s) & LOWER24b_MASK;
220 a += BIT_SHIFT(k[0], k[1], s);
221 b += BIT_SHIFT(k[1], k[2], s) & LOWER16b_MASK;
224 a += BIT_SHIFT(k[0], k[1], s);
225 b += BIT_SHIFT(k[1], k[2], s) & LOWER8b_MASK;
228 a += BIT_SHIFT(k[0], k[1], s);
231 a += BIT_SHIFT(k[0], k[1], s) & LOWER24b_MASK;
234 a += BIT_SHIFT(k[0], k[1], s) & LOWER16b_MASK;
237 a += BIT_SHIFT(k[0], k[1], s) & LOWER8b_MASK;
239 /* zero length strings require no mixing */
245 __rte_jhash_final(a, b, c);
251 * A special optimized version that handles 1 or more of uint32_ts.
252 * The length parameter here is the number of uint32_ts in the key.
255 * Key to calculate hash of.
257 * Length of key in units of 4 bytes.
259 * Initialising value of hash.
261 * Calculated hash value.
263 static inline uint32_t
264 rte_jhash2(const uint32_t *k, uint32_t length, uint32_t initval)
268 /* Set up the internal state */
269 a = b = c = RTE_JHASH_GOLDEN_RATIO + (((uint32_t)length) << 2) + initval;
271 /* Handle most of the key */
277 __rte_jhash_mix(a, b, c);
283 /* Handle the last 3 uint32_t's */
293 __rte_jhash_final(a, b, c);
295 /* case 0: nothing left to add */
304 * Same as rte_jhash, but takes two seeds and return two uint32_ts.
305 * pc and pb must be non-null, and *pc and *pb must both be initialized
306 * with seeds. If you pass in (*pb)=0, the output (*pc) will be
307 * the same as the return value from rte_jhash.
310 * Key to calculate hash of.
312 * Length of key in bytes.
314 * IN: seed OUT: primary hash value.
316 * IN: second seed OUT: secondary hash value.
319 rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc, uint32_t *pb)
323 /* Set up the internal state */
324 a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + *pc;
327 /* Check key alignment. For x86 architecture, first case is always optimal */
328 #if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32)
329 const uint32_t *k = key;
330 const uint32_t s = 0;
332 const uint32_t *k = (uint32_t *)(uintptr_t)key & (uintptr_t)~3);
333 const uint32_t s = ((uintptr_t)key & 3) * CHAR_BIT;
337 while (length > 12) {
342 __rte_jhash_mix(a, b, c);
350 c += k[2]; b += k[1]; a += k[0]; break;
352 c += k[2] & LOWER24b_MASK; b += k[1]; a += k[0]; break;
354 c += k[2] & LOWER16b_MASK; b += k[1]; a += k[0]; break;
356 c += k[2] & LOWER8b_MASK; b += k[1]; a += k[0]; break;
358 b += k[1]; a += k[0]; break;
360 b += k[1] & LOWER24b_MASK; a += k[0]; break;
362 b += k[1] & LOWER16b_MASK; a += k[0]; break;
364 b += k[1] & LOWER8b_MASK; a += k[0]; break;
368 a += k[0] & LOWER24b_MASK; break;
370 a += k[0] & LOWER16b_MASK; break;
372 a += k[0] & LOWER8b_MASK; break;
373 /* zero length strings require no mixing */
380 /* all but the last block: affect some 32 bits of (a, b, c) */
381 while (length > 12) {
382 a += BIT_SHIFT(k[0], k[1], s);
383 b += BIT_SHIFT(k[1], k[2], s);
384 c += BIT_SHIFT(k[2], k[3], s);
385 __rte_jhash_mix(a, b, c);
391 /* last block: affect all 32 bits of (c) */
394 a += BIT_SHIFT(k[0], k[1], s);
395 b += BIT_SHIFT(k[1], k[2], s);
396 c += BIT_SHIFT(k[2], k[3], s);
399 a += BIT_SHIFT(k[0], k[1], s);
400 b += BIT_SHIFT(k[1], k[2], s);
401 c += BIT_SHIFT(k[2], k[3], s) & LOWER24b_MASK;
404 a += BIT_SHIFT(k[0], k[1], s);
405 b += BIT_SHIFT(k[1], k[2], s);
406 c += BIT_SHIFT(k[2], k[3], s) & LOWER16b_MASK;
409 a += BIT_SHIFT(k[0], k[1], s);
410 b += BIT_SHIFT(k[1], k[2], s);
411 c += BIT_SHIFT(k[2], k[3], s) & LOWER8b_MASK;
414 a += BIT_SHIFT(k[0], k[1], s);
415 b += BIT_SHIFT(k[1], k[2], s);
418 a += BIT_SHIFT(k[0], k[1], s);
419 b += BIT_SHIFT(k[1], k[2], s) & LOWER24b_MASK;
422 a += BIT_SHIFT(k[0], k[1], s);
423 b += BIT_SHIFT(k[1], k[2], s) & LOWER16b_MASK;
426 a += BIT_SHIFT(k[0], k[1], s);
427 b += BIT_SHIFT(k[1], k[2], s) & LOWER8b_MASK;
430 a += BIT_SHIFT(k[0], k[1], s);
433 a += BIT_SHIFT(k[0], k[1], s) & LOWER24b_MASK;
436 a += BIT_SHIFT(k[0], k[1], s) & LOWER16b_MASK;
439 a += BIT_SHIFT(k[0], k[1], s) & LOWER8b_MASK;
441 /* zero length strings require no mixing */
449 __rte_jhash_final(a, b, c);
456 * Same as rte_jhash2, but takes two seeds and return two uint32_ts.
457 * pc and pb must be non-null, and *pc and *pb must both be initialized
458 * with seeds. If you pass in (*pb)=0, the output (*pc) will be
459 * the same as the return value from rte_jhash2.
462 * Key to calculate hash of.
464 * Length of key in units of 4 bytes.
466 * IN: seed OUT: primary hash value.
468 * IN: second seed OUT: secondary hash value.
471 rte_jhash2_2hashes(const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t *pb)
475 /* Set up the internal state */
476 a = b = c = RTE_JHASH_GOLDEN_RATIO + (((uint32_t)length) << 2) + *pc;
479 /* Handle most of the key */
485 __rte_jhash_mix(a, b, c);
491 /* Handle the last 3 uint32_t's */
501 __rte_jhash_final(a, b, c);
503 /* case 0: nothing left to add */
512 static inline uint32_t
513 __rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
515 a += RTE_JHASH_GOLDEN_RATIO + initval;
516 b += RTE_JHASH_GOLDEN_RATIO + initval;
517 c += RTE_JHASH_GOLDEN_RATIO + initval;
519 __rte_jhash_final(a, b, c);
525 * A special ultra-optimized versions that knows it is hashing exactly
529 * First word to calcuate hash of.
531 * Second word to calcuate hash of.
533 * Third word to calcuate hash of.
535 * Initialising value of hash.
537 * Calculated hash value.
539 static inline uint32_t
540 rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
542 return __rte_jhash_3words(a + 12, b + 12, c + 12, initval);
546 * A special ultra-optimized versions that knows it is hashing exactly
550 * First word to calcuate hash of.
552 * Second word to calcuate hash of.
554 * Initialising value of hash.
556 * Calculated hash value.
558 static inline uint32_t
559 rte_jhash_2words(uint32_t a, uint32_t b, uint32_t initval)
561 return __rte_jhash_3words(a + 8, b + 8, 8, initval);
565 * A special ultra-optimized versions that knows it is hashing exactly
569 * Word to calcuate hash of.
571 * Initialising value of hash.
573 * Calculated hash value.
575 static inline uint32_t
576 rte_jhash_1word(uint32_t a, uint32_t initval)
578 return __rte_jhash_3words(a + 4, 4, 4, initval);
585 #endif /* _RTE_JHASH_H */