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lookup3.c
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1 /* -------------------------------------------------------------------- */
2 /*
3 * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
4 *
5 * These are functions for producing 32-bit hashes for hash table lookup.
6 * jlu32w(), jlu32l(), jlu32lpair(), jlu32b(), _JLU3_MIX(), and _JLU3_FINAL()
7 * are externally useful functions. Routines to test the hash are included
8 * if SELF_TEST is defined. You can use this free for any purpose. It's in
9 * the public domain. It has no warranty.
10 *
11 * You probably want to use jlu32l(). jlu32l() and jlu32b()
12 * hash byte arrays. jlu32l() is is faster than jlu32b() on
13 * little-endian machines. Intel and AMD are little-endian machines.
14 * On second thought, you probably want jlu32lpair(), which is identical to
15 * jlu32l() except it returns two 32-bit hashes for the price of one.
16 * You could implement jlu32bpair() if you wanted but I haven't bothered here.
17 *
18 * If you want to find a hash of, say, exactly 7 integers, do
19 * a = i1; b = i2; c = i3;
20 * _JLU3_MIX(a,b,c);
21 * a += i4; b += i5; c += i6;
22 * _JLU3_MIX(a,b,c);
23 * a += i7;
24 * _JLU3_FINAL(a,b,c);
25 * then use c as the hash value. If you have a variable size array of
26 * 4-byte integers to hash, use jlu32w(). If you have a byte array (like
27 * a character string), use jlu32l(). If you have several byte arrays, or
28 * a mix of things, see the comments above jlu32l().
29 *
30 * Why is this so big? I read 12 bytes at a time into 3 4-byte integers,
31 * then mix those integers. This is fast (you can do a lot more thorough
32 * mixing with 12*3 instructions on 3 integers than you can with 3 instructions
33 * on 1 byte), but shoehorning those bytes into integers efficiently is messy.
34 */
35 /* -------------------------------------------------------------------- */
36
37 #include "system.h"
38 #include "rpmiotypes.h"
39 #include "debug.h"
40
41 #if defined(_JLU3_SELFTEST)
42 # define _JLU3_jlu32w 1
43 # define _JLU3_jlu32l 1
44 # define _JLU3_jlu32lpair 1
45 # define _JLU3_jlu32b 1
46 #endif
47
48 /*@-redef@*/
49 /*@unchecked@*/
50 static const union _dbswap {
51 const rpmuint32_t ui;
52 const unsigned char uc[4];
53 } endian = { .ui = 0x11223344 };
54 # define HASH_LITTLE_ENDIAN (endian.uc[0] == (unsigned char) 0x44)
55 # define HASH_BIG_ENDIAN (endian.uc[0] == (unsigned char) 0x11)
56 /*@=redef@*/
57
58 #ifndef ROTL32
59 # define ROTL32(x, s) (((x) << (s)) | ((x) >> (32 - (s))))
60 #endif
61
62 /* NOTE: The _size parameter should be in bytes. */
63 #define _JLU3_INIT(_h, _size) (0xdeadbeef + ((rpmuint32_t)(_size)) + (_h))
64
65 /* -------------------------------------------------------------------- */
66 /*
67 * _JLU3_MIX -- mix 3 32-bit values reversibly.
68 *
69 * This is reversible, so any information in (a,b,c) before _JLU3_MIX() is
70 * still in (a,b,c) after _JLU3_MIX().
71 *
72 * If four pairs of (a,b,c) inputs are run through _JLU3_MIX(), or through
73 * _JLU3_MIX() in reverse, there are at least 32 bits of the output that
74 * are sometimes the same for one pair and different for another pair.
75 * This was tested for:
76 * * pairs that differed by one bit, by two bits, in any combination
77 * of top bits of (a,b,c), or in any combination of bottom bits of
78 * (a,b,c).
79 * * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
80 * the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
81 * is commonly produced by subtraction) look like a single 1-bit
82 * difference.
83 * * the base values were pseudorandom, all zero but one bit set, or
84 * all zero plus a counter that starts at zero.
85 *
86 * Some k values for my "a-=c; a^=ROTL32(c,k); c+=b;" arrangement that
87 * satisfy this are
88 * 4 6 8 16 19 4
89 * 9 15 3 18 27 15
90 * 14 9 3 7 17 3
91 * Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
92 * for "differ" defined as + with a one-bit base and a two-bit delta. I
93 * used http://burtleburtle.net/bob/hash/avalanche.html to choose
94 * the operations, constants, and arrangements of the variables.
95 *
96 * This does not achieve avalanche. There are input bits of (a,b,c)
97 * that fail to affect some output bits of (a,b,c), especially of a. The
98 * most thoroughly mixed value is c, but it doesn't really even achieve
99 * avalanche in c.
100 *
101 * This allows some parallelism. Read-after-writes are good at doubling
102 * the number of bits affected, so the goal of mixing pulls in the opposite
103 * direction as the goal of parallelism. I did what I could. Rotates
104 * seem to cost as much as shifts on every machine I could lay my hands
105 * on, and rotates are much kinder to the top and bottom bits, so I used
106 * rotates.
107 */
108 /* -------------------------------------------------------------------- */
109 #define _JLU3_MIX(a,b,c) \
110 { \
111 a -= c; a ^= ROTL32(c, 4); c += b; \
112 b -= a; b ^= ROTL32(a, 6); a += c; \
113 c -= b; c ^= ROTL32(b, 8); b += a; \
114 a -= c; a ^= ROTL32(c,16); c += b; \
115 b -= a; b ^= ROTL32(a,19); a += c; \
116 c -= b; c ^= ROTL32(b, 4); b += a; \
117 }
118
119 /* -------------------------------------------------------------------- */
143 /* -------------------------------------------------------------------- */
144 #define _JLU3_FINAL(a,b,c) \
145 { \
146 c ^= b; c -= ROTL32(b,14); \
147 a ^= c; a -= ROTL32(c,11); \
148 b ^= a; b -= ROTL32(a,25); \
149 c ^= b; c -= ROTL32(b,16); \
150 a ^= c; a -= ROTL32(c,4); \
151 b ^= a; b -= ROTL32(a,14); \
152 c ^= b; c -= ROTL32(b,24); \
153 }
154
155 #if defined(_JLU3_jlu32w)
156 rpmuint32_t jlu32w(rpmuint32_t h, /*@null@*/ const rpmuint32_t *k, size_t size)
157 /*@*/;
158 /* -------------------------------------------------------------------- */
175 /* -------------------------------------------------------------------- */
176 rpmuint32_t jlu32w(rpmuint32_t h, const rpmuint32_t *k, size_t size)
177 {
178 rpmuint32_t a = _JLU3_INIT(h, (size * sizeof(*k)));
179 rpmuint32_t b = a;
180 rpmuint32_t c = a;
181
182 if (k == NULL)
183 goto exit;
184
185 /*----------------------------------------------- handle most of the key */
186 while (size > 3) {
187 a += k[0];
188 b += k[1];
189 c += k[2];
190 _JLU3_MIX(a,b,c);
191 size -= 3;
192 k += 3;
193 }
194
195 /*----------------------------------------- handle the last 3 rpmuint32_t's */
196 switch (size) {
197 case 3 : c+=k[2];
198 case 2 : b+=k[1];
199 case 1 : a+=k[0];
200 _JLU3_FINAL(a,b,c);
201 /*@fallthrough@*/
202 case 0:
203 break;
204 }
205 /*---------------------------------------------------- report the result */
206 exit:
207 return c;
208 }
209 #endif /* defined(_JLU3_jlu32w) */
210
211 #if defined(_JLU3_jlu32l)
212 rpmuint32_t jlu32l(rpmuint32_t h, const void *key, size_t size)
213 /*@*/;
214 /* -------------------------------------------------------------------- */
215 /*
216 * jlu32l() -- hash a variable-length key into a 32-bit value
217 * h : can be any 4-byte value
218 * k : the key (the unaligned variable-length array of bytes)
219 * size : the size of the key, counting by bytes
220 * Returns a 32-bit value. Every bit of the key affects every bit of
221 * the return value. Two keys differing by one or two bits will have
222 * totally different hash values.
223 *
224 * The best hash table sizes are powers of 2. There is no need to do
225 * mod a prime (mod is sooo slow!). If you need less than 32 bits,
226 * use a bitmask. For example, if you need only 10 bits, do
227 * h = (h & hashmask(10));
228 * In which case, the hash table should have hashsize(10) elements.
229 *
230 * If you are hashing n strings (rpmuint8_t **)k, do it like this:
231 * for (i=0, h=0; i<n; ++i) h = jlu32l(h, k[i], len[i]);
232 *
233 * By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this
234 * code any way you wish, private, educational, or commercial. It's free.
235 *
236 * Use for hash table lookup, or anything where one collision in 2^^32 is
237 * acceptable. Do NOT use for cryptographic purposes.
238 *
239 * @param h the previous hash, or an arbitrary value
240 * @param *k the key, an array of rpmuint8_t values
241 * @param size the size of the key
242 * @return the lookup3 hash
243 */
244 /* -------------------------------------------------------------------- */
245 rpmuint32_t jlu32l(rpmuint32_t h, const void *key, size_t size)
246 {
247 union { const void *ptr; size_t i; } u;
248 rpmuint32_t a = _JLU3_INIT(h, size);
249 rpmuint32_t b = a;
250 rpmuint32_t c = a;
251
252 if (key == NULL)
253 goto exit;
254
255 u.ptr = key;
256 if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
257 const rpmuint32_t *k = (const rpmuint32_t *)key; /* read 32-bit chunks */
258 #ifdef VALGRIND
259 const rpmuint8_t *k8;
260 #endif
261
262 /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
263 while (size > 12) {
264 a += k[0];
265 b += k[1];
266 c += k[2];
267 _JLU3_MIX(a,b,c);
268 size -= 12;
269 k += 3;
270 }
271
272 /*------------------------- handle the last (probably partial) block */
273 /*
274 * "k[2]&0xffffff" actually reads beyond the end of the string, but
275 * then masks off the part it's not allowed to read. Because the
276 * string is aligned, the masked-off tail is in the same word as the
277 * rest of the string. Every machine with memory protection I've seen
278 * does it on word boundaries, so is OK with this. But VALGRIND will
279 * still catch it and complain. The masking trick does make the hash
280 * noticably faster for short strings (like English words).
281 */
282 #ifndef VALGRIND
283
284 switch (size) {
285 case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
286 case 11: c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
287 case 10: c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
288 case 9: c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
289 case 8: b += k[1]; a+=k[0]; break;
290 case 7: b += k[1]&0xffffff; a+=k[0]; break;
291 case 6: b += k[1]&0xffff; a+=k[0]; break;
292 case 5: b += k[1]&0xff; a+=k[0]; break;
293 case 4: a += k[0]; break;
294 case 3: a += k[0]&0xffffff; break;
295 case 2: a += k[0]&0xffff; break;
296 case 1: a += k[0]&0xff; break;
297 case 0: goto exit;
298 }
299
300 #else /* make valgrind happy */
301
302 k8 = (const rpmuint8_t *)k;
303 switch (size) {
304 case 12: c += k[2]; b+=k[1]; a+=k[0] break;
305 case 11: c += ((rpmuint32_t)k8[10])<<16; /*@fallthrough@*/
306 case 10: c += ((rpmuint32_t)k8[9])<<8; /*@fallthrough@*/
307 case 9: c += k8[8]; /*@fallthrough@*/
308 case 8: b += k[1]; a+=k[0]; break;
309 case 7: b += ((rpmuint32_t)k8[6])<<16; /*@fallthrough@*/
310 case 6: b += ((rpmuint32_t)k8[5])<<8; /*@fallthrough@*/
311 case 5: b += k8[4]; /*@fallthrough@*/
312 case 4: a += k[0]; break;
313 case 3: a += ((rpmuint32_t)k8[2])<<16; /*@fallthrough@*/
314 case 2: a += ((rpmuint32_t)k8[1])<<8; /*@fallthrough@*/
315 case 1: a += k8[0]; break;
316 case 0: goto exit;
317 }
318
319 #endif /* !valgrind */
320
321 } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
322 const rpmuint16_t *k = (const rpmuint16_t *)key; /* read 16-bit chunks */
323 const rpmuint8_t *k8;
324
325 /*----------- all but last block: aligned reads and different mixing */
326 while (size > 12) {
327 a += k[0] + (((rpmuint32_t)k[1])<<16);
328 b += k[2] + (((rpmuint32_t)k[3])<<16);
329 c += k[4] + (((rpmuint32_t)k[5])<<16);
330 _JLU3_MIX(a,b,c);
331 size -= 12;
332 k += 6;
333 }
334
335 /*------------------------- handle the last (probably partial) block */
336 k8 = (const rpmuint8_t *)k;
337 switch (size) {
338 case 12:
339 c += k[4]+(((rpmuint32_t)k[5])<<16);
340 b += k[2]+(((rpmuint32_t)k[3])<<16);
341 a += k[0]+(((rpmuint32_t)k[1])<<16);
342 break;
343 case 11:
344 c += ((rpmuint32_t)k8[10])<<16;
345 /*@fallthrough@*/
346 case 10:
347 c += (rpmuint32_t)k[4];
348 b += k[2]+(((rpmuint32_t)k[3])<<16);
349 a += k[0]+(((rpmuint32_t)k[1])<<16);
350 break;
351 case 9:
352 c += (rpmuint32_t)k8[8];
353 /*@fallthrough@*/
354 case 8:
355 b += k[2]+(((rpmuint32_t)k[3])<<16);
356 a += k[0]+(((rpmuint32_t)k[1])<<16);
357 break;
358 case 7:
359 b += ((rpmuint32_t)k8[6])<<16;
360 /*@fallthrough@*/
361 case 6:
362 b += (rpmuint32_t)k[2];
363 a += k[0]+(((rpmuint32_t)k[1])<<16);
364 break;
365 case 5:
366 b += (rpmuint32_t)k8[4];
367 /*@fallthrough@*/
368 case 4:
369 a += k[0]+(((rpmuint32_t)k[1])<<16);
370 break;
371 case 3:
372 a += ((rpmuint32_t)k8[2])<<16;
373 /*@fallthrough@*/
374 case 2:
375 a += (rpmuint32_t)k[0];
376 break;
377 case 1:
378 a += (rpmuint32_t)k8[0];
379 break;
380 case 0:
381 goto exit;
382 }
383
384 } else { /* need to read the key one byte at a time */
385 const rpmuint8_t *k = (const rpmuint8_t *)key;
386
387 /*----------- all but the last block: affect some 32 bits of (a,b,c) */
388 while (size > 12) {
389 a += (rpmuint32_t)k[0];
390 a += ((rpmuint32_t)k[1])<<8;
391 a += ((rpmuint32_t)k[2])<<16;
392 a += ((rpmuint32_t)k[3])<<24;
393 b += (rpmuint32_t)k[4];
394 b += ((rpmuint32_t)k[5])<<8;
395 b += ((rpmuint32_t)k[6])<<16;
396 b += ((rpmuint32_t)k[7])<<24;
397 c += (rpmuint32_t)k[8];
398 c += ((rpmuint32_t)k[9])<<8;
399 c += ((rpmuint32_t)k[10])<<16;
400 c += ((rpmuint32_t)k[11])<<24;
401 _JLU3_MIX(a,b,c);
402 size -= 12;
403 k += 12;
404 }
405
406 /*---------------------------- last block: affect all 32 bits of (c) */
407 switch (size) {
408 case 12: c += ((rpmuint32_t)k[11])<<24; /*@fallthrough@*/
409 case 11: c += ((rpmuint32_t)k[10])<<16; /*@fallthrough@*/
410 case 10: c += ((rpmuint32_t)k[9])<<8; /*@fallthrough@*/
411 case 9: c += (rpmuint32_t)k[8]; /*@fallthrough@*/
412 case 8: b += ((rpmuint32_t)k[7])<<24; /*@fallthrough@*/
413 case 7: b += ((rpmuint32_t)k[6])<<16; /*@fallthrough@*/
414 case 6: b += ((rpmuint32_t)k[5])<<8; /*@fallthrough@*/
415 case 5: b += (rpmuint32_t)k[4]; /*@fallthrough@*/
416 case 4: a += ((rpmuint32_t)k[3])<<24; /*@fallthrough@*/
417 case 3: a += ((rpmuint32_t)k[2])<<16; /*@fallthrough@*/
418 case 2: a += ((rpmuint32_t)k[1])<<8; /*@fallthrough@*/
419 case 1: a += (rpmuint32_t)k[0];
420 break;
421 case 0:
422 goto exit;
423 }
424 }
425
426 _JLU3_FINAL(a,b,c);
427
428 exit:
429 return c;
430 }
431 #endif /* defined(_JLU3_jlu32l) */
432
433 #if defined(_JLU3_jlu32lpair)
434 void jlu32lpair(/*@null@*/ const void *key, size_t size,
435 rpmuint32_t *pc, rpmuint32_t *pb)
436 /*@modifies *pc, *pb@*/;
453 void jlu32lpair(const void *key, size_t size, rpmuint32_t *pc, rpmuint32_t *pb)
454 {
455 union { const void *ptr; size_t i; } u;
456 rpmuint32_t a = _JLU3_INIT(*pc, size);
457 rpmuint32_t b = a;
458 rpmuint32_t c = a;
459
460 if (key == NULL)
461 goto exit;
462
463 c += *pb; /* Add the secondary hash. */
464
465 u.ptr = key;
466 if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
467 const rpmuint32_t *k = (const rpmuint32_t *)key; /* read 32-bit chunks */
468 #ifdef VALGRIND
469 const rpmuint8_t *k8;
470 #endif
471
472 /*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
473 while (size > 12) {
474 a += k[0];
475 b += k[1];
476 c += k[2];
477 _JLU3_MIX(a,b,c);
478 size -= 12;
479 k += 3;
480 }
481 /*------------------------- handle the last (probably partial) block */
482 /*
483 * "k[2]&0xffffff" actually reads beyond the end of the string, but
484 * then masks off the part it's not allowed to read. Because the
485 * string is aligned, the masked-off tail is in the same word as the
486 * rest of the string. Every machine with memory protection I've seen
487 * does it on word boundaries, so is OK with this. But VALGRIND will
488 * still catch it and complain. The masking trick does make the hash
489 * noticably faster for short strings (like English words).
490 */
491 #ifndef VALGRIND
492
493 switch (size) {
494 case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
495 case 11: c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
496 case 10: c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
497 case 9: c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
498 case 8: b += k[1]; a+=k[0]; break;
499 case 7: b += k[1]&0xffffff; a+=k[0]; break;
500 case 6: b += k[1]&0xffff; a+=k[0]; break;
501 case 5: b += k[1]&0xff; a+=k[0]; break;
502 case 4: a += k[0]; break;
503 case 3: a += k[0]&0xffffff; break;
504 case 2: a += k[0]&0xffff; break;
505 case 1: a += k[0]&0xff; break;
506 case 0: goto exit;
507 }
508
509 #else /* make valgrind happy */
510
511 k8 = (const rpmuint8_t *)k;
512 switch (size) {
513 case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
514 case 11: c += ((rpmuint32_t)k8[10])<<16; /*@fallthrough@*/
515 case 10: c += ((rpmuint32_t)k8[9])<<8; /*@fallthrough@*/
516 case 9: c += k8[8]; /*@fallthrough@*/
517 case 8: b += k[1]; a+=k[0]; break;
518 case 7: b += ((rpmuint32_t)k8[6])<<16; /*@fallthrough@*/
519 case 6: b += ((rpmuint32_t)k8[5])<<8; /*@fallthrough@*/
520 case 5: b += k8[4]; /*@fallthrough@*/
521 case 4: a += k[0]; break;
522 case 3: a += ((rpmuint32_t)k8[2])<<16; /*@fallthrough@*/
523 case 2: a += ((rpmuint32_t)k8[1])<<8; /*@fallthrough@*/
524 case 1: a += k8[0]; break;
525 case 0: goto exit;
526 }
527
528 #endif /* !valgrind */
529
530 } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
531 const rpmuint16_t *k = (const rpmuint16_t *)key; /* read 16-bit chunks */
532 const rpmuint8_t *k8;
533
534 /*----------- all but last block: aligned reads and different mixing */
535 while (size > 12) {
536 a += k[0] + (((rpmuint32_t)k[1])<<16);
537 b += k[2] + (((rpmuint32_t)k[3])<<16);
538 c += k[4] + (((rpmuint32_t)k[5])<<16);
539 _JLU3_MIX(a,b,c);
540 size -= 12;
541 k += 6;
542 }
543
544 /*------------------------- handle the last (probably partial) block */
545 k8 = (const rpmuint8_t *)k;
546 switch (size) {
547 case 12:
548 c += k[4]+(((rpmuint32_t)k[5])<<16);
549 b += k[2]+(((rpmuint32_t)k[3])<<16);
550 a += k[0]+(((rpmuint32_t)k[1])<<16);
551 break;
552 case 11:
553 c += ((rpmuint32_t)k8[10])<<16;
554 /*@fallthrough@*/
555 case 10:
556 c += k[4];
557 b += k[2]+(((rpmuint32_t)k[3])<<16);
558 a += k[0]+(((rpmuint32_t)k[1])<<16);
559 break;
560 case 9:
561 c += k8[8];
562 /*@fallthrough@*/
563 case 8:
564 b += k[2]+(((rpmuint32_t)k[3])<<16);
565 a += k[0]+(((rpmuint32_t)k[1])<<16);
566 break;
567 case 7:
568 b += ((rpmuint32_t)k8[6])<<16;
569 /*@fallthrough@*/
570 case 6:
571 b += k[2];
572 a += k[0]+(((rpmuint32_t)k[1])<<16);
573 break;
574 case 5:
575 b += k8[4];
576 /*@fallthrough@*/
577 case 4:
578 a += k[0]+(((rpmuint32_t)k[1])<<16);
579 break;
580 case 3:
581 a += ((rpmuint32_t)k8[2])<<16;
582 /*@fallthrough@*/
583 case 2:
584 a += k[0];
585 break;
586 case 1:
587 a += k8[0];
588 break;
589 case 0:
590 goto exit;
591 }
592
593 } else { /* need to read the key one byte at a time */
594 const rpmuint8_t *k = (const rpmuint8_t *)key;
595
596 /*----------- all but the last block: affect some 32 bits of (a,b,c) */
597 while (size > 12) {
598 a += k[0];
599 a += ((rpmuint32_t)k[1])<<8;
600 a += ((rpmuint32_t)k[2])<<16;
601 a += ((rpmuint32_t)k[3])<<24;
602 b += k[4];
603 b += ((rpmuint32_t)k[5])<<8;
604 b += ((rpmuint32_t)k[6])<<16;
605 b += ((rpmuint32_t)k[7])<<24;
606 c += k[8];
607 c += ((rpmuint32_t)k[9])<<8;
608 c += ((rpmuint32_t)k[10])<<16;
609 c += ((rpmuint32_t)k[11])<<24;
610 _JLU3_MIX(a,b,c);
611 size -= 12;
612 k += 12;
613 }
614
615 /*---------------------------- last block: affect all 32 bits of (c) */
616 switch (size) {
617 case 12: c += ((rpmuint32_t)k[11])<<24; /*@fallthrough@*/
618 case 11: c += ((rpmuint32_t)k[10])<<16; /*@fallthrough@*/
619 case 10: c += ((rpmuint32_t)k[9])<<8; /*@fallthrough@*/
620 case 9: c += k[8]; /*@fallthrough@*/
621 case 8: b += ((rpmuint32_t)k[7])<<24; /*@fallthrough@*/
622 case 7: b += ((rpmuint32_t)k[6])<<16; /*@fallthrough@*/
623 case 6: b += ((rpmuint32_t)k[5])<<8; /*@fallthrough@*/
624 case 5: b += k[4]; /*@fallthrough@*/
625 case 4: a += ((rpmuint32_t)k[3])<<24; /*@fallthrough@*/
626 case 3: a += ((rpmuint32_t)k[2])<<16; /*@fallthrough@*/
627 case 2: a += ((rpmuint32_t)k[1])<<8; /*@fallthrough@*/
628 case 1: a += k[0]; /*@fallthrough@*/
629 break;
630 case 0:
631 goto exit;
632 }
633 }
634
635 _JLU3_FINAL(a,b,c);
636
637 exit:
638 *pc = c;
639 *pb = b;
640 return;
641 }
642 #endif /* defined(_JLU3_jlu32lpair) */
643
644 #if defined(_JLU3_jlu32b)
645 rpmuint32_t jlu32b(rpmuint32_t h, /*@null@*/ const void *key, size_t size)
646 /*@*/;
647 /*
648 * jlu32b():
649 * This is the same as jlu32w() on big-endian machines. It is different
650 * from jlu32l() on all machines. jlu32b() takes advantage of
651 * big-endian byte ordering.
652 *
653 * @param h the previous hash, or an arbitrary value
654 * @param *k the key, an array of rpmuint8_t values
655 * @param size the size of the key
656 * @return the lookup3 hash
657 */
658 rpmuint32_t jlu32b(rpmuint32_t h, const void *key, size_t size)
659 {
660 union { const void *ptr; size_t i; } u;
661 rpmuint32_t a = _JLU3_INIT(h, size);
662 rpmuint32_t b = a;
663 rpmuint32_t c = a;
664
665 if (key == NULL)
666 return h;
667
668 u.ptr = key;
669 if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
670 const rpmuint32_t *k = (const rpmuint32_t *)key; /* read 32-bit chunks */
671 #ifdef VALGRIND
672 const rpmuint8_t *k8;
673 #endif
674
675 /*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
676 while (size > 12) {
677 a += k[0];
678 b += k[1];
679 c += k[2];
680 _JLU3_MIX(a,b,c);
681 size -= 12;
682 k += 3;
683 }
684
685 /*------------------------- handle the last (probably partial) block */
686 /*
687 * "k[2]<<8" actually reads beyond the end of the string, but
688 * then shifts out the part it's not allowed to read. Because the
689 * string is aligned, the illegal read is in the same word as the
690 * rest of the string. Every machine with memory protection I've seen
691 * does it on word boundaries, so is OK with this. But VALGRIND will
692 * still catch it and complain. The masking trick does make the hash
693 * noticably faster for short strings (like English words).
694 */
695 #ifndef VALGRIND
696
697 switch (size) {
698 case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
699 case 11: c += k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
700 case 10: c += k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
701 case 9: c += k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
702 case 8: b += k[1]; a+=k[0]; break;
703 case 7: b += k[1]&0xffffff00; a+=k[0]; break;
704 case 6: b += k[1]&0xffff0000; a+=k[0]; break;
705 case 5: b += k[1]&0xff000000; a+=k[0]; break;
706 case 4: a += k[0]; break;
707 case 3: a += k[0]&0xffffff00; break;
708 case 2: a += k[0]&0xffff0000; break;
709 case 1: a += k[0]&0xff000000; break;
710 case 0: goto exit;
711 }
712
713 #else /* make valgrind happy */
714
715 k8 = (const rpmuint8_t *)k;
716 switch (size) { /* all the case statements fall through */
717 case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
718 case 11: c += ((rpmuint32_t)k8[10])<<8; /*@fallthrough@*/
719 case 10: c += ((rpmuint32_t)k8[9])<<16; /*@fallthrough@*/
720 case 9: c += ((rpmuint32_t)k8[8])<<24; /*@fallthrough@*/
721 case 8: b += k[1]; a+=k[0]; break;
722 case 7: b += ((rpmuint32_t)k8[6])<<8; /*@fallthrough@*/
723 case 6: b += ((rpmuint32_t)k8[5])<<16; /*@fallthrough@*/
724 case 5: b += ((rpmuint32_t)k8[4])<<24; /*@fallthrough@*/
725 case 4: a += k[0]; break;
726 case 3: a += ((rpmuint32_t)k8[2])<<8; /*@fallthrough@*/
727 case 2: a += ((rpmuint32_t)k8[1])<<16; /*@fallthrough@*/
728 case 1: a += ((rpmuint32_t)k8[0])<<24; break;
729 case 0: goto exit;
730 }
731
732 #endif /* !VALGRIND */
733
734 } else { /* need to read the key one byte at a time */
735 const rpmuint8_t *k = (const rpmuint8_t *)key;
736
737 /*----------- all but the last block: affect some 32 bits of (a,b,c) */
738 while (size > 12) {
739 a += ((rpmuint32_t)k[0])<<24;
740 a += ((rpmuint32_t)k[1])<<16;
741 a += ((rpmuint32_t)k[2])<<8;
742 a += ((rpmuint32_t)k[3]);
743 b += ((rpmuint32_t)k[4])<<24;
744 b += ((rpmuint32_t)k[5])<<16;
745 b += ((rpmuint32_t)k[6])<<8;
746 b += ((rpmuint32_t)k[7]);
747 c += ((rpmuint32_t)k[8])<<24;
748 c += ((rpmuint32_t)k[9])<<16;
749 c += ((rpmuint32_t)k[10])<<8;
750 c += ((rpmuint32_t)k[11]);
751 _JLU3_MIX(a,b,c);
752 size -= 12;
753 k += 12;
754 }
755
756 /*---------------------------- last block: affect all 32 bits of (c) */
757 switch (size) { /* all the case statements fall through */
758 case 12: c += k[11]; /*@fallthrough@*/
759 case 11: c += ((rpmuint32_t)k[10])<<8; /*@fallthrough@*/
760 case 10: c += ((rpmuint32_t)k[9])<<16; /*@fallthrough@*/
761 case 9: c += ((rpmuint32_t)k[8])<<24; /*@fallthrough@*/
762 case 8: b += k[7]; /*@fallthrough@*/
763 case 7: b += ((rpmuint32_t)k[6])<<8; /*@fallthrough@*/
764 case 6: b += ((rpmuint32_t)k[5])<<16; /*@fallthrough@*/
765 case 5: b += ((rpmuint32_t)k[4])<<24; /*@fallthrough@*/
766 case 4: a += k[3]; /*@fallthrough@*/
767 case 3: a += ((rpmuint32_t)k[2])<<8; /*@fallthrough@*/
768 case 2: a += ((rpmuint32_t)k[1])<<16; /*@fallthrough@*/
769 case 1: a += ((rpmuint32_t)k[0])<<24; /*@fallthrough@*/
770 break;
771 case 0:
772 goto exit;
773 }
774 }
775
776 _JLU3_FINAL(a,b,c);
777
778 exit:
779 return c;
780 }
781 #endif /* defined(_JLU3_jlu32b) */
782
783 #if defined(_JLU3_SELFTEST)
784
785 /* used for timings */
786 static void driver1(void)
787 /*@*/
788 {
789 rpmuint8_t buf[256];
790 rpmuint32_t i;
791 rpmuint32_t h=0;
792 time_t a,z;
793
794 time(&a);
795 for (i=0; i<256; ++i) buf[i] = 'x';
796 for (i=0; i<1; ++i) {
797 h = jlu32l(h, &buf[0], sizeof(buf[0]));
798 }
799 time(&z);
800 if (z-a > 0) printf("time %d %.8x\n", (int)(z-a), h);
801 }
802
803 /* check that every input bit changes every output bit half the time */
804 #define HASHSTATE 1
805 #define HASHLEN 1
806 #define MAXPAIR 60
807 #define MAXLEN 70
808 static void driver2(void)
809 /*@*/
810 {
811 rpmuint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1];
812 rpmuint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z;
813 rpmuint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE];
814 rpmuint32_t x[HASHSTATE],y[HASHSTATE];
815 rpmuint32_t hlen;
816
817 printf("No more than %d trials should ever be needed \n",MAXPAIR/2);
818 for (hlen=0; hlen < MAXLEN; ++hlen) {
819 z=0;
820 for (i=0; i<hlen; ++i) { /*-------------- for each input byte, */
821 for (j=0; j<8; ++j) { /*--------------- for each input bit, */
822 for (m=1; m<8; ++m) { /*--- for serveral possible initvals, */
823 for (l=0; l<HASHSTATE; ++l)
824 e[l]=f[l]=g[l]=h[l]=x[l]=y[l]=~((rpmuint32_t)0);
825
826 /* check that every output bit is affected by that input bit */
827 for (k=0; k<MAXPAIR; k+=2) {
828 rpmuint32_t finished=1;
829 /* keys have one bit different */
830 for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (rpmuint8_t)0;}
831 /* have a and b be two keys differing in only one bit */
832 a[i] ^= (k<<j);
833 a[i] ^= (k>>(8-j));
834 c[0] = jlu32l(m, a, hlen);
835 b[i] ^= ((k+1)<<j);
836 b[i] ^= ((k+1)>>(8-j));
837 d[0] = jlu32l(m, b, hlen);
838 /* check every bit is 1, 0, set, and not set at least once */
839 for (l=0; l<HASHSTATE; ++l) {
840 e[l] &= (c[l]^d[l]);
841 f[l] &= ~(c[l]^d[l]);
842 g[l] &= c[l];
843 h[l] &= ~c[l];
844 x[l] &= d[l];
845 y[l] &= ~d[l];
846 if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0;
847 }
848 if (finished) break;
849 }
850 if (k>z) z=k;
851 if (k == MAXPAIR) {
852 printf("Some bit didn't change: ");
853 printf("%.8x %.8x %.8x %.8x %.8x %.8x ",
854 e[0],f[0],g[0],h[0],x[0],y[0]);
855 printf("i %d j %d m %d len %d\n", i, j, m, hlen);
856 }
857 if (z == MAXPAIR) goto done;
858 }
859 }
860 }
861 done:
862 if (z < MAXPAIR) {
863 printf("Mix success %2d bytes %2d initvals ",i,m);
864 printf("required %d trials\n", z/2);
865 }
866 }
867 printf("\n");
868 }
869
870 /* Check for reading beyond the end of the buffer and alignment problems */
871 static void driver3(void)
872 /*@*/
873 {
874 rpmuint8_t buf[MAXLEN+20], *b;
875 rpmuint32_t len;
876 rpmuint8_t q[] = "This is the time for all good men to come to the aid of their country...";
877 rpmuint32_t h;
878 rpmuint8_t qq[] = "xThis is the time for all good men to come to the aid of their country...";
879 rpmuint32_t i;
880 rpmuint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country...";
881 rpmuint32_t j;
882 rpmuint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country...";
883 rpmuint32_t ref,x,y;
884 rpmuint8_t *p;
885 rpmuint32_t m = 13;
886
887 printf("Endianness. These lines should all be the same (for values filled in):\n");
888 printf("%.8x %.8x %.8x\n",
889 jlu32w(m, (const rpmuint32_t *)q, (sizeof(q)-1)/4),
890 jlu32w(m, (const rpmuint32_t *)q, (sizeof(q)-5)/4),
891 jlu32w(m, (const rpmuint32_t *)q, (sizeof(q)-9)/4));
892 p = q;
893 printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
894 jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
895 jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
896 jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
897 jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
898 jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
899 jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
900 p = &qq[1];
901 printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
902 jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
903 jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
904 jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
905 jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
906 jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
907 jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
908 p = &qqq[2];
909 printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
910 jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
911 jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
912 jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
913 jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
914 jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
915 jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
916 p = &qqqq[3];
917 printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
918 jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
919 jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
920 jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
921 jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
922 jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
923 jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
924 printf("\n");
925 for (h=0, b=buf+1; h<8; ++h, ++b) {
926 for (i=0; i<MAXLEN; ++i) {
927 len = i;
928 for (j=0; j<i; ++j)
929 *(b+j)=0;
930
931 /* these should all be equal */
932 m = 1;
933 ref = jlu32l(m, b, len);
934 *(b+i)=(rpmuint8_t)~0;
935 *(b-1)=(rpmuint8_t)~0;
936 x = jlu32l(m, b, len);
937 y = jlu32l(m, b, len);
938 if ((ref != x) || (ref != y))
939 printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y, h, i);
940 }
941 }
942 }
943
944 /* check for problems with nulls */
945 static void driver4(void)
946 /*@*/
947 {
948 rpmuint8_t buf[1];
949 rpmuint32_t h;
950 rpmuint32_t i;
951 rpmuint32_t state[HASHSTATE];
952
953 buf[0] = ~0;
954 for (i=0; i<HASHSTATE; ++i)
955 state[i] = 1;
956 printf("These should all be different\n");
957 h = 0;
958 for (i=0; i<8; ++i) {
959 h = jlu32l(h, buf, 0);
960 printf("%2ld 0-byte strings, hash is %.8x\n", (long)i, h);
961 }
962 }
963
964
965 int main(int argc, char ** argv)
966 {
967 driver1(); /* test that the key is hashed: used for timings */
968 driver2(); /* test that whole key is hashed thoroughly */
969 driver3(); /* test that nothing but the key is hashed */
970 driver4(); /* test hashing multiple buffers (all buffers are null) */
971 return 1;
972 }
973
974 #endif /* _JLU3_SELFTEST */