Line data Source code
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 <stdint.h>
38 :
39 : #if defined(_JLU3_SELFTEST)
40 : # define _JLU3_jlu32w 1
41 : # define _JLU3_jlu32l 1
42 : # define _JLU3_jlu32lpair 1
43 : # define _JLU3_jlu32b 1
44 : #endif
45 :
46 : /*@-redef@*/
47 : /*@unchecked@*/
48 : static const union _dbswap {
49 : const uint32_t ui;
50 : const unsigned char uc[4];
51 : } endian = { .ui = 0x11223344 };
52 : # define HASH_LITTLE_ENDIAN (endian.uc[0] == (unsigned char) 0x44)
53 : # define HASH_BIG_ENDIAN (endian.uc[0] == (unsigned char) 0x11)
54 : /*@=redef@*/
55 :
56 : #ifndef ROTL32
57 : # define ROTL32(x, s) (((x) << (s)) | ((x) >> (32 - (s))))
58 : #endif
59 :
60 : /* NOTE: The _size parameter should be in bytes. */
61 : #define _JLU3_INIT(_h, _size) (0xdeadbeef + ((uint32_t)(_size)) + (_h))
62 :
63 : /* -------------------------------------------------------------------- */
64 : /*
65 : * _JLU3_MIX -- mix 3 32-bit values reversibly.
66 : *
67 : * This is reversible, so any information in (a,b,c) before _JLU3_MIX() is
68 : * still in (a,b,c) after _JLU3_MIX().
69 : *
70 : * If four pairs of (a,b,c) inputs are run through _JLU3_MIX(), or through
71 : * _JLU3_MIX() in reverse, there are at least 32 bits of the output that
72 : * are sometimes the same for one pair and different for another pair.
73 : * This was tested for:
74 : * * pairs that differed by one bit, by two bits, in any combination
75 : * of top bits of (a,b,c), or in any combination of bottom bits of
76 : * (a,b,c).
77 : * * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
78 : * the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
79 : * is commonly produced by subtraction) look like a single 1-bit
80 : * difference.
81 : * * the base values were pseudorandom, all zero but one bit set, or
82 : * all zero plus a counter that starts at zero.
83 : *
84 : * Some k values for my "a-=c; a^=ROTL32(c,k); c+=b;" arrangement that
85 : * satisfy this are
86 : * 4 6 8 16 19 4
87 : * 9 15 3 18 27 15
88 : * 14 9 3 7 17 3
89 : * Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
90 : * for "differ" defined as + with a one-bit base and a two-bit delta. I
91 : * used http://burtleburtle.net/bob/hash/avalanche.html to choose
92 : * the operations, constants, and arrangements of the variables.
93 : *
94 : * This does not achieve avalanche. There are input bits of (a,b,c)
95 : * that fail to affect some output bits of (a,b,c), especially of a. The
96 : * most thoroughly mixed value is c, but it doesn't really even achieve
97 : * avalanche in c.
98 : *
99 : * This allows some parallelism. Read-after-writes are good at doubling
100 : * the number of bits affected, so the goal of mixing pulls in the opposite
101 : * direction as the goal of parallelism. I did what I could. Rotates
102 : * seem to cost as much as shifts on every machine I could lay my hands
103 : * on, and rotates are much kinder to the top and bottom bits, so I used
104 : * rotates.
105 : */
106 : /* -------------------------------------------------------------------- */
107 : #define _JLU3_MIX(a,b,c) \
108 : { \
109 : a -= c; a ^= ROTL32(c, 4); c += b; \
110 : b -= a; b ^= ROTL32(a, 6); a += c; \
111 : c -= b; c ^= ROTL32(b, 8); b += a; \
112 : a -= c; a ^= ROTL32(c,16); c += b; \
113 : b -= a; b ^= ROTL32(a,19); a += c; \
114 : c -= b; c ^= ROTL32(b, 4); b += a; \
115 : }
116 :
117 : /* -------------------------------------------------------------------- */
118 : /**
119 : * _JLU3_FINAL -- final mixing of 3 32-bit values (a,b,c) into c
120 : *
121 : * Pairs of (a,b,c) values differing in only a few bits will usually
122 : * produce values of c that look totally different. This was tested for
123 : * * pairs that differed by one bit, by two bits, in any combination
124 : * of top bits of (a,b,c), or in any combination of bottom bits of
125 : * (a,b,c).
126 : * * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
127 : * the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
128 : * is commonly produced by subtraction) look like a single 1-bit
129 : * difference.
130 : * * the base values were pseudorandom, all zero but one bit set, or
131 : * all zero plus a counter that starts at zero.
132 : *
133 : * These constants passed:
134 : * 14 11 25 16 4 14 24
135 : * 12 14 25 16 4 14 24
136 : * and these came close:
137 : * 4 8 15 26 3 22 24
138 : * 10 8 15 26 3 22 24
139 : * 11 8 15 26 3 22 24
140 : */
141 : /* -------------------------------------------------------------------- */
142 : #define _JLU3_FINAL(a,b,c) \
143 : { \
144 : c ^= b; c -= ROTL32(b,14); \
145 : a ^= c; a -= ROTL32(c,11); \
146 : b ^= a; b -= ROTL32(a,25); \
147 : c ^= b; c -= ROTL32(b,16); \
148 : a ^= c; a -= ROTL32(c,4); \
149 : b ^= a; b -= ROTL32(a,14); \
150 : c ^= b; c -= ROTL32(b,24); \
151 : }
152 :
153 : #if defined(_JLU3_jlu32w)
154 : uint32_t jlu32w(uint32_t h, /*@null@*/ const uint32_t *k, size_t size)
155 : /*@*/;
156 : /* -------------------------------------------------------------------- */
157 : /**
158 : * This works on all machines. To be useful, it requires
159 : * -- that the key be an array of uint32_t's, and
160 : * -- that the size be the number of uint32_t's in the key
161 : *
162 : * The function jlu32w() is identical to jlu32l() on little-endian
163 : * machines, and identical to jlu32b() on big-endian machines,
164 : * except that the size has to be measured in uint32_ts rather than in
165 : * bytes. jlu32l() is more complicated than jlu32w() only because
166 : * jlu32l() has to dance around fitting the key bytes into registers.
167 : *
168 : * @param h the previous hash, or an arbitrary value
169 : * @param *k the key, an array of uint32_t values
170 : * @param size the size of the key, in uint32_ts
171 : * @return the lookup3 hash
172 : */
173 : /* -------------------------------------------------------------------- */
174 : uint32_t jlu32w(uint32_t h, const uint32_t *k, size_t size)
175 : {
176 : uint32_t a = _JLU3_INIT(h, (size * sizeof(*k)));
177 : uint32_t b = a;
178 : uint32_t c = a;
179 :
180 : if (k == NULL)
181 : goto exit;
182 :
183 : /*----------------------------------------------- handle most of the key */
184 : while (size > 3) {
185 : a += k[0];
186 : b += k[1];
187 : c += k[2];
188 : _JLU3_MIX(a,b,c);
189 : size -= 3;
190 : k += 3;
191 : }
192 :
193 : /*----------------------------------------- handle the last 3 uint32_t's */
194 : switch (size) {
195 : case 3 : c+=k[2];
196 : case 2 : b+=k[1];
197 : case 1 : a+=k[0];
198 : _JLU3_FINAL(a,b,c);
199 : /*@fallthrough@*/
200 : case 0:
201 : break;
202 : }
203 : /*---------------------------------------------------- report the result */
204 : exit:
205 : return c;
206 : }
207 : #endif /* defined(_JLU3_jlu32w) */
208 :
209 : #if defined(_JLU3_jlu32l)
210 : uint32_t jlu32l(uint32_t h, const void *key, size_t size)
211 : /*@*/;
212 : /* -------------------------------------------------------------------- */
213 : /*
214 : * jlu32l() -- hash a variable-length key into a 32-bit value
215 : * h : can be any 4-byte value
216 : * k : the key (the unaligned variable-length array of bytes)
217 : * size : the size of the key, counting by bytes
218 : * Returns a 32-bit value. Every bit of the key affects every bit of
219 : * the return value. Two keys differing by one or two bits will have
220 : * totally different hash values.
221 : *
222 : * The best hash table sizes are powers of 2. There is no need to do
223 : * mod a prime (mod is sooo slow!). If you need less than 32 bits,
224 : * use a bitmask. For example, if you need only 10 bits, do
225 : * h = (h & hashmask(10));
226 : * In which case, the hash table should have hashsize(10) elements.
227 : *
228 : * If you are hashing n strings (uint8_t **)k, do it like this:
229 : * for (i=0, h=0; i<n; ++i) h = jlu32l(h, k[i], len[i]);
230 : *
231 : * By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this
232 : * code any way you wish, private, educational, or commercial. It's free.
233 : *
234 : * Use for hash table lookup, or anything where one collision in 2^^32 is
235 : * acceptable. Do NOT use for cryptographic purposes.
236 : *
237 : * @param h the previous hash, or an arbitrary value
238 : * @param *k the key, an array of uint8_t values
239 : * @param size the size of the key
240 : * @return the lookup3 hash
241 : */
242 : /* -------------------------------------------------------------------- */
243 : uint32_t jlu32l(uint32_t h, const void *key, size_t size)
244 : {
245 : union { const void *ptr; size_t i; } u;
246 : uint32_t a = _JLU3_INIT(h, size);
247 : uint32_t b = a;
248 : uint32_t c = a;
249 :
250 : if (key == NULL)
251 : goto exit;
252 :
253 : u.ptr = key;
254 : if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
255 : const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
256 : #ifdef VALGRIND
257 : const uint8_t *k8;
258 : #endif
259 :
260 : /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
261 : while (size > 12) {
262 : a += k[0];
263 : b += k[1];
264 : c += k[2];
265 : _JLU3_MIX(a,b,c);
266 : size -= 12;
267 : k += 3;
268 : }
269 :
270 : /*------------------------- handle the last (probably partial) block */
271 : /*
272 : * "k[2]&0xffffff" actually reads beyond the end of the string, but
273 : * then masks off the part it's not allowed to read. Because the
274 : * string is aligned, the masked-off tail is in the same word as the
275 : * rest of the string. Every machine with memory protection I've seen
276 : * does it on word boundaries, so is OK with this. But VALGRIND will
277 : * still catch it and complain. The masking trick does make the hash
278 : * noticably faster for short strings (like English words).
279 : */
280 : #ifndef VALGRIND
281 :
282 : switch (size) {
283 : case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
284 : case 11: c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
285 : case 10: c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
286 : case 9: c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
287 : case 8: b += k[1]; a+=k[0]; break;
288 : case 7: b += k[1]&0xffffff; a+=k[0]; break;
289 : case 6: b += k[1]&0xffff; a+=k[0]; break;
290 : case 5: b += k[1]&0xff; a+=k[0]; break;
291 : case 4: a += k[0]; break;
292 : case 3: a += k[0]&0xffffff; break;
293 : case 2: a += k[0]&0xffff; break;
294 : case 1: a += k[0]&0xff; break;
295 : case 0: goto exit;
296 : }
297 :
298 : #else /* make valgrind happy */
299 :
300 : k8 = (const uint8_t *)k;
301 : switch (size) {
302 : case 12: c += k[2]; b+=k[1]; a+=k[0] break;
303 : case 11: c += ((uint32_t)k8[10])<<16; /*@fallthrough@*/
304 : case 10: c += ((uint32_t)k8[9])<<8; /*@fallthrough@*/
305 : case 9: c += k8[8]; /*@fallthrough@*/
306 : case 8: b += k[1]; a+=k[0]; break;
307 : case 7: b += ((uint32_t)k8[6])<<16; /*@fallthrough@*/
308 : case 6: b += ((uint32_t)k8[5])<<8; /*@fallthrough@*/
309 : case 5: b += k8[4]; /*@fallthrough@*/
310 : case 4: a += k[0]; break;
311 : case 3: a += ((uint32_t)k8[2])<<16; /*@fallthrough@*/
312 : case 2: a += ((uint32_t)k8[1])<<8; /*@fallthrough@*/
313 : case 1: a += k8[0]; break;
314 : case 0: goto exit;
315 : }
316 :
317 : #endif /* !valgrind */
318 :
319 : } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
320 : const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
321 : const uint8_t *k8;
322 :
323 : /*----------- all but last block: aligned reads and different mixing */
324 : while (size > 12) {
325 : a += k[0] + (((uint32_t)k[1])<<16);
326 : b += k[2] + (((uint32_t)k[3])<<16);
327 : c += k[4] + (((uint32_t)k[5])<<16);
328 : _JLU3_MIX(a,b,c);
329 : size -= 12;
330 : k += 6;
331 : }
332 :
333 : /*------------------------- handle the last (probably partial) block */
334 : k8 = (const uint8_t *)k;
335 : switch (size) {
336 : case 12:
337 : c += k[4]+(((uint32_t)k[5])<<16);
338 : b += k[2]+(((uint32_t)k[3])<<16);
339 : a += k[0]+(((uint32_t)k[1])<<16);
340 : break;
341 : case 11:
342 : c += ((uint32_t)k8[10])<<16;
343 : /*@fallthrough@*/
344 : case 10:
345 : c += (uint32_t)k[4];
346 : b += k[2]+(((uint32_t)k[3])<<16);
347 : a += k[0]+(((uint32_t)k[1])<<16);
348 : break;
349 : case 9:
350 : c += (uint32_t)k8[8];
351 : /*@fallthrough@*/
352 : case 8:
353 : b += k[2]+(((uint32_t)k[3])<<16);
354 : a += k[0]+(((uint32_t)k[1])<<16);
355 : break;
356 : case 7:
357 : b += ((uint32_t)k8[6])<<16;
358 : /*@fallthrough@*/
359 : case 6:
360 : b += (uint32_t)k[2];
361 : a += k[0]+(((uint32_t)k[1])<<16);
362 : break;
363 : case 5:
364 : b += (uint32_t)k8[4];
365 : /*@fallthrough@*/
366 : case 4:
367 : a += k[0]+(((uint32_t)k[1])<<16);
368 : break;
369 : case 3:
370 : a += ((uint32_t)k8[2])<<16;
371 : /*@fallthrough@*/
372 : case 2:
373 : a += (uint32_t)k[0];
374 : break;
375 : case 1:
376 : a += (uint32_t)k8[0];
377 : break;
378 : case 0:
379 : goto exit;
380 : }
381 :
382 : } else { /* need to read the key one byte at a time */
383 : const uint8_t *k = (const uint8_t *)key;
384 :
385 : /*----------- all but the last block: affect some 32 bits of (a,b,c) */
386 : while (size > 12) {
387 : a += (uint32_t)k[0];
388 : a += ((uint32_t)k[1])<<8;
389 : a += ((uint32_t)k[2])<<16;
390 : a += ((uint32_t)k[3])<<24;
391 : b += (uint32_t)k[4];
392 : b += ((uint32_t)k[5])<<8;
393 : b += ((uint32_t)k[6])<<16;
394 : b += ((uint32_t)k[7])<<24;
395 : c += (uint32_t)k[8];
396 : c += ((uint32_t)k[9])<<8;
397 : c += ((uint32_t)k[10])<<16;
398 : c += ((uint32_t)k[11])<<24;
399 : _JLU3_MIX(a,b,c);
400 : size -= 12;
401 : k += 12;
402 : }
403 :
404 : /*---------------------------- last block: affect all 32 bits of (c) */
405 : switch (size) {
406 : case 12: c += ((uint32_t)k[11])<<24; /*@fallthrough@*/
407 : case 11: c += ((uint32_t)k[10])<<16; /*@fallthrough@*/
408 : case 10: c += ((uint32_t)k[9])<<8; /*@fallthrough@*/
409 : case 9: c += (uint32_t)k[8]; /*@fallthrough@*/
410 : case 8: b += ((uint32_t)k[7])<<24; /*@fallthrough@*/
411 : case 7: b += ((uint32_t)k[6])<<16; /*@fallthrough@*/
412 : case 6: b += ((uint32_t)k[5])<<8; /*@fallthrough@*/
413 : case 5: b += (uint32_t)k[4]; /*@fallthrough@*/
414 : case 4: a += ((uint32_t)k[3])<<24; /*@fallthrough@*/
415 : case 3: a += ((uint32_t)k[2])<<16; /*@fallthrough@*/
416 : case 2: a += ((uint32_t)k[1])<<8; /*@fallthrough@*/
417 : case 1: a += (uint32_t)k[0];
418 : break;
419 : case 0:
420 : goto exit;
421 : }
422 : }
423 :
424 : _JLU3_FINAL(a,b,c);
425 :
426 : exit:
427 : return c;
428 : }
429 : #endif /* defined(_JLU3_jlu32l) */
430 :
431 : #if defined(_JLU3_jlu32lpair)
432 : /**
433 : * jlu32lpair: return 2 32-bit hash values.
434 : *
435 : * This is identical to jlu32l(), except it returns two 32-bit hash
436 : * values instead of just one. This is good enough for hash table
437 : * lookup with 2^^64 buckets, or if you want a second hash if you're not
438 : * happy with the first, or if you want a probably-unique 64-bit ID for
439 : * the key. *pc is better mixed than *pb, so use *pc first. If you want
440 : * a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
441 : *
442 : * @param h the previous hash, or an arbitrary value
443 : * @param *key the key, an array of uint8_t values
444 : * @param size the size of the key in bytes
445 : * @retval *pc, IN: primary initval, OUT: primary hash
446 : * *retval *pb IN: secondary initval, OUT: secondary hash
447 : */
448 0 : void jlu32lpair(const void *key, size_t size, uint32_t *pc, uint32_t *pb)
449 : {
450 : union { const void *ptr; size_t i; } u;
451 0 : uint32_t a = _JLU3_INIT(*pc, size);
452 0 : uint32_t b = a;
453 0 : uint32_t c = a;
454 :
455 0 : if (key == NULL)
456 0 : goto exit;
457 :
458 0 : c += *pb; /* Add the secondary hash. */
459 :
460 0 : u.ptr = key;
461 0 : if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
462 0 : const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
463 : #ifdef VALGRIND
464 : const uint8_t *k8;
465 : #endif
466 :
467 : /*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
468 0 : while (size > (size_t)12) {
469 0 : a += k[0];
470 0 : b += k[1];
471 0 : c += k[2];
472 0 : _JLU3_MIX(a,b,c);
473 0 : size -= 12;
474 0 : k += 3;
475 : }
476 : /*------------------------- handle the last (probably partial) block */
477 : /*
478 : * "k[2]&0xffffff" actually reads beyond the end of the string, but
479 : * then masks off the part it's not allowed to read. Because the
480 : * string is aligned, the masked-off tail is in the same word as the
481 : * rest of the string. Every machine with memory protection I've seen
482 : * does it on word boundaries, so is OK with this. But VALGRIND will
483 : * still catch it and complain. The masking trick does make the hash
484 : * noticably faster for short strings (like English words).
485 : */
486 : #ifndef VALGRIND
487 :
488 0 : switch (size) {
489 0 : case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
490 0 : case 11: c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
491 0 : case 10: c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
492 0 : case 9: c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
493 0 : case 8: b += k[1]; a+=k[0]; break;
494 0 : case 7: b += k[1]&0xffffff; a+=k[0]; break;
495 0 : case 6: b += k[1]&0xffff; a+=k[0]; break;
496 0 : case 5: b += k[1]&0xff; a+=k[0]; break;
497 0 : case 4: a += k[0]; break;
498 0 : case 3: a += k[0]&0xffffff; break;
499 0 : case 2: a += k[0]&0xffff; break;
500 0 : case 1: a += k[0]&0xff; break;
501 0 : case 0: goto exit;
502 : }
503 :
504 : #else /* make valgrind happy */
505 :
506 : k8 = (const uint8_t *)k;
507 : switch (size) {
508 : case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
509 : case 11: c += ((uint32_t)k8[10])<<16; /*@fallthrough@*/
510 : case 10: c += ((uint32_t)k8[9])<<8; /*@fallthrough@*/
511 : case 9: c += k8[8]; /*@fallthrough@*/
512 : case 8: b += k[1]; a+=k[0]; break;
513 : case 7: b += ((uint32_t)k8[6])<<16; /*@fallthrough@*/
514 : case 6: b += ((uint32_t)k8[5])<<8; /*@fallthrough@*/
515 : case 5: b += k8[4]; /*@fallthrough@*/
516 : case 4: a += k[0]; break;
517 : case 3: a += ((uint32_t)k8[2])<<16; /*@fallthrough@*/
518 : case 2: a += ((uint32_t)k8[1])<<8; /*@fallthrough@*/
519 : case 1: a += k8[0]; break;
520 : case 0: goto exit;
521 : }
522 :
523 : #endif /* !valgrind */
524 :
525 0 : } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
526 0 : const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
527 : const uint8_t *k8;
528 :
529 : /*----------- all but last block: aligned reads and different mixing */
530 0 : while (size > (size_t)12) {
531 0 : a += k[0] + (((uint32_t)k[1])<<16);
532 0 : b += k[2] + (((uint32_t)k[3])<<16);
533 0 : c += k[4] + (((uint32_t)k[5])<<16);
534 0 : _JLU3_MIX(a,b,c);
535 0 : size -= 12;
536 0 : k += 6;
537 : }
538 :
539 : /*------------------------- handle the last (probably partial) block */
540 0 : k8 = (const uint8_t *)k;
541 0 : switch (size) {
542 0 : case 12:
543 0 : c += k[4]+(((uint32_t)k[5])<<16);
544 0 : b += k[2]+(((uint32_t)k[3])<<16);
545 0 : a += k[0]+(((uint32_t)k[1])<<16);
546 0 : break;
547 0 : case 11:
548 0 : c += ((uint32_t)k8[10])<<16;
549 : /*@fallthrough@*/
550 0 : case 10:
551 0 : c += k[4];
552 0 : b += k[2]+(((uint32_t)k[3])<<16);
553 0 : a += k[0]+(((uint32_t)k[1])<<16);
554 0 : break;
555 0 : case 9:
556 0 : c += k8[8];
557 : /*@fallthrough@*/
558 0 : case 8:
559 0 : b += k[2]+(((uint32_t)k[3])<<16);
560 0 : a += k[0]+(((uint32_t)k[1])<<16);
561 0 : break;
562 0 : case 7:
563 0 : b += ((uint32_t)k8[6])<<16;
564 : /*@fallthrough@*/
565 0 : case 6:
566 0 : b += k[2];
567 0 : a += k[0]+(((uint32_t)k[1])<<16);
568 0 : break;
569 0 : case 5:
570 0 : b += k8[4];
571 : /*@fallthrough@*/
572 0 : case 4:
573 0 : a += k[0]+(((uint32_t)k[1])<<16);
574 0 : break;
575 0 : case 3:
576 0 : a += ((uint32_t)k8[2])<<16;
577 : /*@fallthrough@*/
578 0 : case 2:
579 0 : a += k[0];
580 0 : break;
581 0 : case 1:
582 0 : a += k8[0];
583 0 : break;
584 0 : case 0:
585 0 : goto exit;
586 : }
587 :
588 : } else { /* need to read the key one byte at a time */
589 0 : const uint8_t *k = (const uint8_t *)key;
590 :
591 : /*----------- all but the last block: affect some 32 bits of (a,b,c) */
592 0 : while (size > (size_t)12) {
593 0 : a += k[0];
594 0 : a += ((uint32_t)k[1])<<8;
595 0 : a += ((uint32_t)k[2])<<16;
596 0 : a += ((uint32_t)k[3])<<24;
597 0 : b += k[4];
598 0 : b += ((uint32_t)k[5])<<8;
599 0 : b += ((uint32_t)k[6])<<16;
600 0 : b += ((uint32_t)k[7])<<24;
601 0 : c += k[8];
602 0 : c += ((uint32_t)k[9])<<8;
603 0 : c += ((uint32_t)k[10])<<16;
604 0 : c += ((uint32_t)k[11])<<24;
605 0 : _JLU3_MIX(a,b,c);
606 0 : size -= 12;
607 0 : k += 12;
608 : }
609 :
610 : /*---------------------------- last block: affect all 32 bits of (c) */
611 0 : switch (size) {
612 0 : case 12: c += ((uint32_t)k[11])<<24; /*@fallthrough@*/
613 0 : case 11: c += ((uint32_t)k[10])<<16; /*@fallthrough@*/
614 0 : case 10: c += ((uint32_t)k[9])<<8; /*@fallthrough@*/
615 0 : case 9: c += k[8]; /*@fallthrough@*/
616 0 : case 8: b += ((uint32_t)k[7])<<24; /*@fallthrough@*/
617 0 : case 7: b += ((uint32_t)k[6])<<16; /*@fallthrough@*/
618 0 : case 6: b += ((uint32_t)k[5])<<8; /*@fallthrough@*/
619 0 : case 5: b += k[4]; /*@fallthrough@*/
620 0 : case 4: a += ((uint32_t)k[3])<<24; /*@fallthrough@*/
621 0 : case 3: a += ((uint32_t)k[2])<<16; /*@fallthrough@*/
622 0 : case 2: a += ((uint32_t)k[1])<<8; /*@fallthrough@*/
623 0 : case 1: a += k[0];
624 0 : break;
625 0 : case 0:
626 0 : goto exit;
627 : }
628 : }
629 :
630 0 : _JLU3_FINAL(a,b,c);
631 :
632 0 : exit:
633 0 : *pc = c;
634 0 : *pb = b;
635 0 : return;
636 : }
637 : #endif /* defined(_JLU3_jlu32lpair) */
638 :
639 : #if defined(_JLU3_jlu32b)
640 : uint32_t jlu32b(uint32_t h, /*@null@*/ const void *key, size_t size)
641 : /*@*/;
642 : /*
643 : * jlu32b():
644 : * This is the same as jlu32w() on big-endian machines. It is different
645 : * from jlu32l() on all machines. jlu32b() takes advantage of
646 : * big-endian byte ordering.
647 : *
648 : * @param h the previous hash, or an arbitrary value
649 : * @param *k the key, an array of uint8_t values
650 : * @param size the size of the key
651 : * @return the lookup3 hash
652 : */
653 : uint32_t jlu32b(uint32_t h, const void *key, size_t size)
654 : {
655 : union { const void *ptr; size_t i; } u;
656 : uint32_t a = _JLU3_INIT(h, size);
657 : uint32_t b = a;
658 : uint32_t c = a;
659 :
660 : if (key == NULL)
661 : return h;
662 :
663 : u.ptr = key;
664 : if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
665 : const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
666 : #ifdef VALGRIND
667 : const uint8_t *k8;
668 : #endif
669 :
670 : /*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
671 : while (size > 12) {
672 : a += k[0];
673 : b += k[1];
674 : c += k[2];
675 : _JLU3_MIX(a,b,c);
676 : size -= 12;
677 : k += 3;
678 : }
679 :
680 : /*------------------------- handle the last (probably partial) block */
681 : /*
682 : * "k[2]<<8" actually reads beyond the end of the string, but
683 : * then shifts out the part it's not allowed to read. Because the
684 : * string is aligned, the illegal read is in the same word as the
685 : * rest of the string. Every machine with memory protection I've seen
686 : * does it on word boundaries, so is OK with this. But VALGRIND will
687 : * still catch it and complain. The masking trick does make the hash
688 : * noticably faster for short strings (like English words).
689 : */
690 : #ifndef VALGRIND
691 :
692 : switch (size) {
693 : case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
694 : case 11: c += k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
695 : case 10: c += k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
696 : case 9: c += k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
697 : case 8: b += k[1]; a+=k[0]; break;
698 : case 7: b += k[1]&0xffffff00; a+=k[0]; break;
699 : case 6: b += k[1]&0xffff0000; a+=k[0]; break;
700 : case 5: b += k[1]&0xff000000; a+=k[0]; break;
701 : case 4: a += k[0]; break;
702 : case 3: a += k[0]&0xffffff00; break;
703 : case 2: a += k[0]&0xffff0000; break;
704 : case 1: a += k[0]&0xff000000; break;
705 : case 0: goto exit;
706 : }
707 :
708 : #else /* make valgrind happy */
709 :
710 : k8 = (const uint8_t *)k;
711 : switch (size) { /* all the case statements fall through */
712 : case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
713 : case 11: c += ((uint32_t)k8[10])<<8; /*@fallthrough@*/
714 : case 10: c += ((uint32_t)k8[9])<<16; /*@fallthrough@*/
715 : case 9: c += ((uint32_t)k8[8])<<24; /*@fallthrough@*/
716 : case 8: b += k[1]; a+=k[0]; break;
717 : case 7: b += ((uint32_t)k8[6])<<8; /*@fallthrough@*/
718 : case 6: b += ((uint32_t)k8[5])<<16; /*@fallthrough@*/
719 : case 5: b += ((uint32_t)k8[4])<<24; /*@fallthrough@*/
720 : case 4: a += k[0]; break;
721 : case 3: a += ((uint32_t)k8[2])<<8; /*@fallthrough@*/
722 : case 2: a += ((uint32_t)k8[1])<<16; /*@fallthrough@*/
723 : case 1: a += ((uint32_t)k8[0])<<24; break;
724 : case 0: goto exit;
725 : }
726 :
727 : #endif /* !VALGRIND */
728 :
729 : } else { /* need to read the key one byte at a time */
730 : const uint8_t *k = (const uint8_t *)key;
731 :
732 : /*----------- all but the last block: affect some 32 bits of (a,b,c) */
733 : while (size > 12) {
734 : a += ((uint32_t)k[0])<<24;
735 : a += ((uint32_t)k[1])<<16;
736 : a += ((uint32_t)k[2])<<8;
737 : a += ((uint32_t)k[3]);
738 : b += ((uint32_t)k[4])<<24;
739 : b += ((uint32_t)k[5])<<16;
740 : b += ((uint32_t)k[6])<<8;
741 : b += ((uint32_t)k[7]);
742 : c += ((uint32_t)k[8])<<24;
743 : c += ((uint32_t)k[9])<<16;
744 : c += ((uint32_t)k[10])<<8;
745 : c += ((uint32_t)k[11]);
746 : _JLU3_MIX(a,b,c);
747 : size -= 12;
748 : k += 12;
749 : }
750 :
751 : /*---------------------------- last block: affect all 32 bits of (c) */
752 : switch (size) { /* all the case statements fall through */
753 : case 12: c += k[11]; /*@fallthrough@*/
754 : case 11: c += ((uint32_t)k[10])<<8; /*@fallthrough@*/
755 : case 10: c += ((uint32_t)k[9])<<16; /*@fallthrough@*/
756 : case 9: c += ((uint32_t)k[8])<<24; /*@fallthrough@*/
757 : case 8: b += k[7]; /*@fallthrough@*/
758 : case 7: b += ((uint32_t)k[6])<<8; /*@fallthrough@*/
759 : case 6: b += ((uint32_t)k[5])<<16; /*@fallthrough@*/
760 : case 5: b += ((uint32_t)k[4])<<24; /*@fallthrough@*/
761 : case 4: a += k[3]; /*@fallthrough@*/
762 : case 3: a += ((uint32_t)k[2])<<8; /*@fallthrough@*/
763 : case 2: a += ((uint32_t)k[1])<<16; /*@fallthrough@*/
764 : case 1: a += ((uint32_t)k[0])<<24; /*@fallthrough@*/
765 : break;
766 : case 0:
767 : goto exit;
768 : }
769 : }
770 :
771 : _JLU3_FINAL(a,b,c);
772 :
773 : exit:
774 : return c;
775 : }
776 : #endif /* defined(_JLU3_jlu32b) */
777 :
778 : #if defined(_JLU3_SELFTEST)
779 :
780 : /* used for timings */
781 : static void driver1(void)
782 : /*@*/
783 : {
784 : uint8_t buf[256];
785 : uint32_t i;
786 : uint32_t h=0;
787 : time_t a,z;
788 :
789 : time(&a);
790 : for (i=0; i<256; ++i) buf[i] = 'x';
791 : for (i=0; i<1; ++i) {
792 : h = jlu32l(h, &buf[0], sizeof(buf[0]));
793 : }
794 : time(&z);
795 : if (z-a > 0) printf("time %d %.8x\n", (int)(z-a), h);
796 : }
797 :
798 : /* check that every input bit changes every output bit half the time */
799 : #define HASHSTATE 1
800 : #define HASHLEN 1
801 : #define MAXPAIR 60
802 : #define MAXLEN 70
803 : static void driver2(void)
804 : /*@*/
805 : {
806 : uint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1];
807 : uint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z;
808 : uint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE];
809 : uint32_t x[HASHSTATE],y[HASHSTATE];
810 : uint32_t hlen;
811 :
812 : printf("No more than %d trials should ever be needed \n",MAXPAIR/2);
813 : for (hlen=0; hlen < MAXLEN; ++hlen) {
814 : z=0;
815 : for (i=0; i<hlen; ++i) { /*-------------- for each input byte, */
816 : for (j=0; j<8; ++j) { /*--------------- for each input bit, */
817 : for (m=1; m<8; ++m) { /*--- for serveral possible initvals, */
818 : for (l=0; l<HASHSTATE; ++l)
819 : e[l]=f[l]=g[l]=h[l]=x[l]=y[l]=~((uint32_t)0);
820 :
821 : /* check that every output bit is affected by that input bit */
822 : for (k=0; k<MAXPAIR; k+=2) {
823 : uint32_t finished=1;
824 : /* keys have one bit different */
825 : for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (uint8_t)0;}
826 : /* have a and b be two keys differing in only one bit */
827 : a[i] ^= (k<<j);
828 : a[i] ^= (k>>(8-j));
829 : c[0] = jlu32l(m, a, hlen);
830 : b[i] ^= ((k+1)<<j);
831 : b[i] ^= ((k+1)>>(8-j));
832 : d[0] = jlu32l(m, b, hlen);
833 : /* check every bit is 1, 0, set, and not set at least once */
834 : for (l=0; l<HASHSTATE; ++l) {
835 : e[l] &= (c[l]^d[l]);
836 : f[l] &= ~(c[l]^d[l]);
837 : g[l] &= c[l];
838 : h[l] &= ~c[l];
839 : x[l] &= d[l];
840 : y[l] &= ~d[l];
841 : if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0;
842 : }
843 : if (finished) break;
844 : }
845 : if (k>z) z=k;
846 : if (k == MAXPAIR) {
847 : printf("Some bit didn't change: ");
848 : printf("%.8x %.8x %.8x %.8x %.8x %.8x ",
849 : e[0],f[0],g[0],h[0],x[0],y[0]);
850 : printf("i %d j %d m %d len %d\n", i, j, m, hlen);
851 : }
852 : if (z == MAXPAIR) goto done;
853 : }
854 : }
855 : }
856 : done:
857 : if (z < MAXPAIR) {
858 : printf("Mix success %2d bytes %2d initvals ",i,m);
859 : printf("required %d trials\n", z/2);
860 : }
861 : }
862 : printf("\n");
863 : }
864 :
865 : /* Check for reading beyond the end of the buffer and alignment problems */
866 : static void driver3(void)
867 : /*@*/
868 : {
869 : uint8_t buf[MAXLEN+20], *b;
870 : uint32_t len;
871 : uint8_t q[] = "This is the time for all good men to come to the aid of their country...";
872 : uint32_t h;
873 : uint8_t qq[] = "xThis is the time for all good men to come to the aid of their country...";
874 : uint32_t i;
875 : uint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country...";
876 : uint32_t j;
877 : uint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country...";
878 : uint32_t ref,x,y;
879 : uint8_t *p;
880 : uint32_t m = 13;
881 :
882 : printf("Endianness. These lines should all be the same (for values filled in):\n");
883 : printf("%.8x %.8x %.8x\n",
884 : jlu32w(m, (const uint32_t *)q, (sizeof(q)-1)/4),
885 : jlu32w(m, (const uint32_t *)q, (sizeof(q)-5)/4),
886 : jlu32w(m, (const uint32_t *)q, (sizeof(q)-9)/4));
887 : p = q;
888 : printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
889 : jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
890 : jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
891 : jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
892 : jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
893 : jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
894 : jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
895 : p = &qq[1];
896 : printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
897 : jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
898 : jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
899 : jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
900 : jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
901 : jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
902 : jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
903 : p = &qqq[2];
904 : printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
905 : jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
906 : jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
907 : jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
908 : jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
909 : jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
910 : jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
911 : p = &qqqq[3];
912 : printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
913 : jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
914 : jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
915 : jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
916 : jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
917 : jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
918 : jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
919 : printf("\n");
920 : for (h=0, b=buf+1; h<8; ++h, ++b) {
921 : for (i=0; i<MAXLEN; ++i) {
922 : len = i;
923 : for (j=0; j<i; ++j)
924 : *(b+j)=0;
925 :
926 : /* these should all be equal */
927 : m = 1;
928 : ref = jlu32l(m, b, len);
929 : *(b+i)=(uint8_t)~0;
930 : *(b-1)=(uint8_t)~0;
931 : x = jlu32l(m, b, len);
932 : y = jlu32l(m, b, len);
933 : if ((ref != x) || (ref != y))
934 : printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y, h, i);
935 : }
936 : }
937 : }
938 :
939 : /* check for problems with nulls */
940 : static void driver4(void)
941 : /*@*/
942 : {
943 : uint8_t buf[1];
944 : uint32_t h;
945 : uint32_t i;
946 : uint32_t state[HASHSTATE];
947 :
948 : buf[0] = ~0;
949 : for (i=0; i<HASHSTATE; ++i)
950 : state[i] = 1;
951 : printf("These should all be different\n");
952 : h = 0;
953 : for (i=0; i<8; ++i) {
954 : h = jlu32l(h, buf, 0);
955 : printf("%2ld 0-byte strings, hash is %.8x\n", (long)i, h);
956 : }
957 : }
958 :
959 :
960 : int main(int argc, char ** argv)
961 : {
962 : driver1(); /* test that the key is hashed: used for timings */
963 : driver2(); /* test that whole key is hashed thoroughly */
964 : driver3(); /* test that nothing but the key is hashed */
965 : driver4(); /* test hashing multiple buffers (all buffers are null) */
966 : return 1;
967 : }
968 :
969 : #endif /* _JLU3_SELFTEST */
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