Line data Source code
1 : /* Slightly modified by Lennart Poettering, to avoid name clashes, and
2 : * unexport a few functions. */
3 :
4 : #include "lookup3.h"
5 :
6 : /*
7 : -------------------------------------------------------------------------------
8 : lookup3.c, by Bob Jenkins, May 2006, Public Domain.
9 :
10 : These are functions for producing 32-bit hashes for hash table lookup.
11 : hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
12 : are externally useful functions. Routines to test the hash are included
13 : if SELF_TEST is defined. You can use this free for any purpose. It's in
14 : the public domain. It has no warranty.
15 :
16 : You probably want to use hashlittle(). hashlittle() and hashbig()
17 : hash byte arrays. hashlittle() is faster than hashbig() on
18 : little-endian machines. Intel and AMD are little-endian machines.
19 : On second thought, you probably want hashlittle2(), which is identical to
20 : hashlittle() except it returns two 32-bit hashes for the price of one.
21 : You could implement hashbig2() if you wanted but I haven't bothered here.
22 :
23 : If you want to find a hash of, say, exactly 7 integers, do
24 : a = i1; b = i2; c = i3;
25 : mix(a,b,c);
26 : a += i4; b += i5; c += i6;
27 : mix(a,b,c);
28 : a += i7;
29 : final(a,b,c);
30 : then use c as the hash value. If you have a variable length array of
31 : 4-byte integers to hash, use hashword(). If you have a byte array (like
32 : a character string), use hashlittle(). If you have several byte arrays, or
33 : a mix of things, see the comments above hashlittle().
34 :
35 : Why is this so big? I read 12 bytes at a time into 3 4-byte integers,
36 : then mix those integers. This is fast (you can do a lot more thorough
37 : mixing with 12*3 instructions on 3 integers than you can with 3 instructions
38 : on 1 byte), but shoehorning those bytes into integers efficiently is messy.
39 : -------------------------------------------------------------------------------
40 : */
41 : /* #define SELF_TEST 1 */
42 :
43 : #include <stdio.h> /* defines printf for tests */
44 : #include <time.h> /* defines time_t for timings in the test */
45 : #include <stdint.h> /* defines uint32_t etc */
46 : #include <sys/param.h> /* attempt to define endianness */
47 : #ifdef linux
48 : # include <endian.h> /* attempt to define endianness */
49 : #endif
50 :
51 : /*
52 : * My best guess at if you are big-endian or little-endian. This may
53 : * need adjustment.
54 : */
55 : #if (defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && \
56 : __BYTE_ORDER == __LITTLE_ENDIAN) || \
57 : (defined(i386) || defined(__i386__) || defined(__i486__) || \
58 : defined(__i586__) || defined(__i686__) || defined(vax) || defined(MIPSEL))
59 : # define HASH_LITTLE_ENDIAN 1
60 : # define HASH_BIG_ENDIAN 0
61 : #elif (defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && \
62 : __BYTE_ORDER == __BIG_ENDIAN) || \
63 : (defined(sparc) || defined(POWERPC) || defined(mc68000) || defined(sel))
64 : # define HASH_LITTLE_ENDIAN 0
65 : # define HASH_BIG_ENDIAN 1
66 : #else
67 : # define HASH_LITTLE_ENDIAN 0
68 : # define HASH_BIG_ENDIAN 0
69 : #endif
70 :
71 : #define hashsize(n) ((uint32_t)1<<(n))
72 : #define hashmask(n) (hashsize(n)-1)
73 : #define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
74 :
75 : /*
76 : -------------------------------------------------------------------------------
77 : mix -- mix 3 32-bit values reversibly.
78 :
79 : This is reversible, so any information in (a,b,c) before mix() is
80 : still in (a,b,c) after mix().
81 :
82 : If four pairs of (a,b,c) inputs are run through mix(), or through
83 : mix() in reverse, there are at least 32 bits of the output that
84 : are sometimes the same for one pair and different for another pair.
85 : This was tested for:
86 : * pairs that differed by one bit, by two bits, in any combination
87 : of top bits of (a,b,c), or in any combination of bottom bits of
88 : (a,b,c).
89 : * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
90 : the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
91 : is commonly produced by subtraction) look like a single 1-bit
92 : difference.
93 : * the base values were pseudorandom, all zero but one bit set, or
94 : all zero plus a counter that starts at zero.
95 :
96 : Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that
97 : satisfy this are
98 : 4 6 8 16 19 4
99 : 9 15 3 18 27 15
100 : 14 9 3 7 17 3
101 : Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
102 : for "differ" defined as + with a one-bit base and a two-bit delta. I
103 : used http://burtleburtle.net/bob/hash/avalanche.html to choose
104 : the operations, constants, and arrangements of the variables.
105 :
106 : This does not achieve avalanche. There are input bits of (a,b,c)
107 : that fail to affect some output bits of (a,b,c), especially of a. The
108 : most thoroughly mixed value is c, but it doesn't really even achieve
109 : avalanche in c.
110 :
111 : This allows some parallelism. Read-after-writes are good at doubling
112 : the number of bits affected, so the goal of mixing pulls in the opposite
113 : direction as the goal of parallelism. I did what I could. Rotates
114 : seem to cost as much as shifts on every machine I could lay my hands
115 : on, and rotates are much kinder to the top and bottom bits, so I used
116 : rotates.
117 : -------------------------------------------------------------------------------
118 : */
119 : #define mix(a,b,c) \
120 : { \
121 : a -= c; a ^= rot(c, 4); c += b; \
122 : b -= a; b ^= rot(a, 6); a += c; \
123 : c -= b; c ^= rot(b, 8); b += a; \
124 : a -= c; a ^= rot(c,16); c += b; \
125 : b -= a; b ^= rot(a,19); a += c; \
126 : c -= b; c ^= rot(b, 4); b += a; \
127 : }
128 :
129 : /*
130 : -------------------------------------------------------------------------------
131 : final -- final mixing of 3 32-bit values (a,b,c) into c
132 :
133 : Pairs of (a,b,c) values differing in only a few bits will usually
134 : produce values of c that look totally different. This was tested for
135 : * pairs that differed by one bit, by two bits, in any combination
136 : of top bits of (a,b,c), or in any combination of bottom bits of
137 : (a,b,c).
138 : * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
139 : the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
140 : is commonly produced by subtraction) look like a single 1-bit
141 : difference.
142 : * the base values were pseudorandom, all zero but one bit set, or
143 : all zero plus a counter that starts at zero.
144 :
145 : These constants passed:
146 : 14 11 25 16 4 14 24
147 : 12 14 25 16 4 14 24
148 : and these came close:
149 : 4 8 15 26 3 22 24
150 : 10 8 15 26 3 22 24
151 : 11 8 15 26 3 22 24
152 : -------------------------------------------------------------------------------
153 : */
154 : #define final(a,b,c) \
155 : { \
156 : c ^= b; c -= rot(b,14); \
157 : a ^= c; a -= rot(c,11); \
158 : b ^= a; b -= rot(a,25); \
159 : c ^= b; c -= rot(b,16); \
160 : a ^= c; a -= rot(c,4); \
161 : b ^= a; b -= rot(a,14); \
162 : c ^= b; c -= rot(b,24); \
163 : }
164 :
165 : /*
166 : --------------------------------------------------------------------
167 : This works on all machines. To be useful, it requires
168 : -- that the key be an array of uint32_t's, and
169 : -- that the length be the number of uint32_t's in the key
170 :
171 : The function hashword() is identical to hashlittle() on little-endian
172 : machines, and identical to hashbig() on big-endian machines,
173 : except that the length has to be measured in uint32_ts rather than in
174 : bytes. hashlittle() is more complicated than hashword() only because
175 : hashlittle() has to dance around fitting the key bytes into registers.
176 : --------------------------------------------------------------------
177 : */
178 0 : uint32_t jenkins_hashword(
179 : const uint32_t *k, /* the key, an array of uint32_t values */
180 : size_t length, /* the length of the key, in uint32_ts */
181 : uint32_t initval) /* the previous hash, or an arbitrary value */
182 : {
183 : uint32_t a,b,c;
184 :
185 : /* Set up the internal state */
186 0 : a = b = c = 0xdeadbeef + (((uint32_t)length)<<2) + initval;
187 :
188 : /*------------------------------------------------- handle most of the key */
189 0 : while (length > 3)
190 : {
191 0 : a += k[0];
192 0 : b += k[1];
193 0 : c += k[2];
194 0 : mix(a,b,c);
195 0 : length -= 3;
196 0 : k += 3;
197 : }
198 :
199 : /*------------------------------------------- handle the last 3 uint32_t's */
200 0 : switch(length) /* all the case statements fall through */
201 : {
202 0 : case 3 : c+=k[2];
203 0 : case 2 : b+=k[1];
204 0 : case 1 : a+=k[0];
205 0 : final(a,b,c);
206 : case 0: /* case 0: nothing left to add */
207 0 : break;
208 : }
209 : /*------------------------------------------------------ report the result */
210 0 : return c;
211 : }
212 :
213 :
214 : /*
215 : --------------------------------------------------------------------
216 : hashword2() -- same as hashword(), but take two seeds and return two
217 : 32-bit values. pc and pb must both be nonnull, and *pc and *pb must
218 : both be initialized with seeds. If you pass in (*pb)==0, the output
219 : (*pc) will be the same as the return value from hashword().
220 : --------------------------------------------------------------------
221 : */
222 0 : void jenkins_hashword2 (
223 : const uint32_t *k, /* the key, an array of uint32_t values */
224 : size_t length, /* the length of the key, in uint32_ts */
225 : uint32_t *pc, /* IN: seed OUT: primary hash value */
226 : uint32_t *pb) /* IN: more seed OUT: secondary hash value */
227 : {
228 : uint32_t a,b,c;
229 :
230 : /* Set up the internal state */
231 0 : a = b = c = 0xdeadbeef + ((uint32_t)(length<<2)) + *pc;
232 0 : c += *pb;
233 :
234 : /*------------------------------------------------- handle most of the key */
235 0 : while (length > 3)
236 : {
237 0 : a += k[0];
238 0 : b += k[1];
239 0 : c += k[2];
240 0 : mix(a,b,c);
241 0 : length -= 3;
242 0 : k += 3;
243 : }
244 :
245 : /*------------------------------------------- handle the last 3 uint32_t's */
246 0 : switch(length) /* all the case statements fall through */
247 : {
248 0 : case 3 : c+=k[2];
249 0 : case 2 : b+=k[1];
250 0 : case 1 : a+=k[0];
251 0 : final(a,b,c);
252 : case 0: /* case 0: nothing left to add */
253 0 : break;
254 : }
255 : /*------------------------------------------------------ report the result */
256 0 : *pc=c; *pb=b;
257 0 : }
258 :
259 :
260 : /*
261 : -------------------------------------------------------------------------------
262 : hashlittle() -- hash a variable-length key into a 32-bit value
263 : k : the key (the unaligned variable-length array of bytes)
264 : length : the length of the key, counting by bytes
265 : initval : can be any 4-byte value
266 : Returns a 32-bit value. Every bit of the key affects every bit of
267 : the return value. Two keys differing by one or two bits will have
268 : totally different hash values.
269 :
270 : The best hash table sizes are powers of 2. There is no need to do
271 : mod a prime (mod is sooo slow!). If you need less than 32 bits,
272 : use a bitmask. For example, if you need only 10 bits, do
273 : h = (h & hashmask(10));
274 : In which case, the hash table should have hashsize(10) elements.
275 :
276 : If you are hashing n strings (uint8_t **)k, do it like this:
277 : for (i=0, h=0; i<n; ++i) h = hashlittle( k[i], len[i], h);
278 :
279 : By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this
280 : code any way you wish, private, educational, or commercial. It's free.
281 :
282 : Use for hash table lookup, or anything where one collision in 2^^32 is
283 : acceptable. Do NOT use for cryptographic purposes.
284 : -------------------------------------------------------------------------------
285 : */
286 :
287 0 : uint32_t jenkins_hashlittle( const void *key, size_t length, uint32_t initval)
288 : {
289 : uint32_t a,b,c; /* internal state */
290 : union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */
291 :
292 : /* Set up the internal state */
293 0 : a = b = c = 0xdeadbeef + ((uint32_t)length) + initval;
294 :
295 0 : u.ptr = key;
296 0 : if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
297 0 : const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
298 :
299 : /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
300 0 : while (length > 12)
301 : {
302 0 : a += k[0];
303 0 : b += k[1];
304 0 : c += k[2];
305 0 : mix(a,b,c);
306 0 : length -= 12;
307 0 : k += 3;
308 : }
309 :
310 : /*----------------------------- handle the last (probably partial) block */
311 : /*
312 : * "k[2]&0xffffff" actually reads beyond the end of the string, but
313 : * then masks off the part it's not allowed to read. Because the
314 : * string is aligned, the masked-off tail is in the same word as the
315 : * rest of the string. Every machine with memory protection I've seen
316 : * does it on word boundaries, so is OK with this. But VALGRIND will
317 : * still catch it and complain. The masking trick does make the hash
318 : * noticeably faster for short strings (like English words).
319 : */
320 : #ifndef VALGRIND
321 :
322 0 : switch(length)
323 : {
324 0 : case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
325 0 : case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
326 0 : case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
327 0 : case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
328 0 : case 8 : b+=k[1]; a+=k[0]; break;
329 0 : case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
330 0 : case 6 : b+=k[1]&0xffff; a+=k[0]; break;
331 0 : case 5 : b+=k[1]&0xff; a+=k[0]; break;
332 0 : case 4 : a+=k[0]; break;
333 0 : case 3 : a+=k[0]&0xffffff; break;
334 0 : case 2 : a+=k[0]&0xffff; break;
335 0 : case 1 : a+=k[0]&0xff; break;
336 0 : case 0 : return c; /* zero length strings require no mixing */
337 : }
338 :
339 : #else /* make valgrind happy */
340 : {
341 : const uint8_t *k8 = (const uint8_t *) k;
342 :
343 : switch(length)
344 : {
345 : case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
346 : case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
347 : case 10: c+=((uint32_t)k8[9])<<8; /* fall through */
348 : case 9 : c+=k8[8]; /* fall through */
349 : case 8 : b+=k[1]; a+=k[0]; break;
350 : case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
351 : case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */
352 : case 5 : b+=k8[4]; /* fall through */
353 : case 4 : a+=k[0]; break;
354 : case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
355 : case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */
356 : case 1 : a+=k8[0]; break;
357 : case 0 : return c;
358 : }
359 : }
360 :
361 : #endif /* !valgrind */
362 :
363 0 : } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
364 0 : const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
365 : const uint8_t *k8;
366 :
367 : /*--------------- all but last block: aligned reads and different mixing */
368 0 : while (length > 12)
369 : {
370 0 : a += k[0] + (((uint32_t)k[1])<<16);
371 0 : b += k[2] + (((uint32_t)k[3])<<16);
372 0 : c += k[4] + (((uint32_t)k[5])<<16);
373 0 : mix(a,b,c);
374 0 : length -= 12;
375 0 : k += 6;
376 : }
377 :
378 : /*----------------------------- handle the last (probably partial) block */
379 0 : k8 = (const uint8_t *)k;
380 0 : switch(length)
381 : {
382 0 : case 12: c+=k[4]+(((uint32_t)k[5])<<16);
383 0 : b+=k[2]+(((uint32_t)k[3])<<16);
384 0 : a+=k[0]+(((uint32_t)k[1])<<16);
385 0 : break;
386 0 : case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
387 0 : case 10: c+=k[4];
388 0 : b+=k[2]+(((uint32_t)k[3])<<16);
389 0 : a+=k[0]+(((uint32_t)k[1])<<16);
390 0 : break;
391 0 : case 9 : c+=k8[8]; /* fall through */
392 0 : case 8 : b+=k[2]+(((uint32_t)k[3])<<16);
393 0 : a+=k[0]+(((uint32_t)k[1])<<16);
394 0 : break;
395 0 : case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
396 0 : case 6 : b+=k[2];
397 0 : a+=k[0]+(((uint32_t)k[1])<<16);
398 0 : break;
399 0 : case 5 : b+=k8[4]; /* fall through */
400 0 : case 4 : a+=k[0]+(((uint32_t)k[1])<<16);
401 0 : break;
402 0 : case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
403 0 : case 2 : a+=k[0];
404 0 : break;
405 0 : case 1 : a+=k8[0];
406 0 : break;
407 0 : case 0 : return c; /* zero length requires no mixing */
408 : }
409 :
410 : } else { /* need to read the key one byte at a time */
411 0 : const uint8_t *k = (const uint8_t *)key;
412 :
413 : /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
414 0 : while (length > 12)
415 : {
416 0 : a += k[0];
417 0 : a += ((uint32_t)k[1])<<8;
418 0 : a += ((uint32_t)k[2])<<16;
419 0 : a += ((uint32_t)k[3])<<24;
420 0 : b += k[4];
421 0 : b += ((uint32_t)k[5])<<8;
422 0 : b += ((uint32_t)k[6])<<16;
423 0 : b += ((uint32_t)k[7])<<24;
424 0 : c += k[8];
425 0 : c += ((uint32_t)k[9])<<8;
426 0 : c += ((uint32_t)k[10])<<16;
427 0 : c += ((uint32_t)k[11])<<24;
428 0 : mix(a,b,c);
429 0 : length -= 12;
430 0 : k += 12;
431 : }
432 :
433 : /*-------------------------------- last block: affect all 32 bits of (c) */
434 0 : switch(length) /* all the case statements fall through */
435 : {
436 0 : case 12: c+=((uint32_t)k[11])<<24;
437 0 : case 11: c+=((uint32_t)k[10])<<16;
438 0 : case 10: c+=((uint32_t)k[9])<<8;
439 0 : case 9 : c+=k[8];
440 0 : case 8 : b+=((uint32_t)k[7])<<24;
441 0 : case 7 : b+=((uint32_t)k[6])<<16;
442 0 : case 6 : b+=((uint32_t)k[5])<<8;
443 0 : case 5 : b+=k[4];
444 0 : case 4 : a+=((uint32_t)k[3])<<24;
445 0 : case 3 : a+=((uint32_t)k[2])<<16;
446 0 : case 2 : a+=((uint32_t)k[1])<<8;
447 0 : case 1 : a+=k[0];
448 0 : break;
449 0 : case 0 : return c;
450 : }
451 : }
452 :
453 0 : final(a,b,c);
454 0 : return c;
455 : }
456 :
457 :
458 : /*
459 : * hashlittle2: return 2 32-bit hash values
460 : *
461 : * This is identical to hashlittle(), except it returns two 32-bit hash
462 : * values instead of just one. This is good enough for hash table
463 : * lookup with 2^^64 buckets, or if you want a second hash if you're not
464 : * happy with the first, or if you want a probably-unique 64-bit ID for
465 : * the key. *pc is better mixed than *pb, so use *pc first. If you want
466 : * a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
467 : */
468 170724 : void jenkins_hashlittle2(
469 : const void *key, /* the key to hash */
470 : size_t length, /* length of the key */
471 : uint32_t *pc, /* IN: primary initval, OUT: primary hash */
472 : uint32_t *pb) /* IN: secondary initval, OUT: secondary hash */
473 : {
474 : uint32_t a,b,c; /* internal state */
475 : union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */
476 :
477 : /* Set up the internal state */
478 170724 : a = b = c = 0xdeadbeef + ((uint32_t)length) + *pc;
479 170724 : c += *pb;
480 :
481 170724 : u.ptr = key;
482 170724 : if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
483 170703 : const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
484 :
485 : /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
486 974227 : while (length > 12)
487 : {
488 632821 : a += k[0];
489 632821 : b += k[1];
490 632821 : c += k[2];
491 632821 : mix(a,b,c);
492 632821 : length -= 12;
493 632821 : k += 3;
494 : }
495 :
496 : /*----------------------------- handle the last (probably partial) block */
497 : /*
498 : * "k[2]&0xffffff" actually reads beyond the end of the string, but
499 : * then masks off the part it's not allowed to read. Because the
500 : * string is aligned, the masked-off tail is in the same word as the
501 : * rest of the string. Every machine with memory protection I've seen
502 : * does it on word boundaries, so is OK with this. But VALGRIND will
503 : * still catch it and complain. The masking trick does make the hash
504 : * noticeably faster for short strings (like English words).
505 : */
506 : #ifndef VALGRIND
507 :
508 170703 : switch(length)
509 : {
510 10846 : case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
511 6453 : case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
512 15794 : case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
513 13037 : case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
514 18737 : case 8 : b+=k[1]; a+=k[0]; break;
515 12169 : case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
516 24196 : case 6 : b+=k[1]&0xffff; a+=k[0]; break;
517 34460 : case 5 : b+=k[1]&0xff; a+=k[0]; break;
518 5444 : case 4 : a+=k[0]; break;
519 6900 : case 3 : a+=k[0]&0xffffff; break;
520 8377 : case 2 : a+=k[0]&0xffff; break;
521 14290 : case 1 : a+=k[0]&0xff; break;
522 0 : case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
523 : }
524 :
525 : #else /* make valgrind happy */
526 :
527 : {
528 : const uint8_t *k8 = (const uint8_t *)k;
529 : switch(length)
530 : {
531 : case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
532 : case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
533 : case 10: c+=((uint32_t)k8[9])<<8; /* fall through */
534 : case 9 : c+=k8[8]; /* fall through */
535 : case 8 : b+=k[1]; a+=k[0]; break;
536 : case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
537 : case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */
538 : case 5 : b+=k8[4]; /* fall through */
539 : case 4 : a+=k[0]; break;
540 : case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
541 : case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */
542 : case 1 : a+=k8[0]; break;
543 : case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
544 : }
545 : }
546 :
547 : #endif /* !valgrind */
548 :
549 21 : } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
550 5 : const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
551 : const uint8_t *k8;
552 :
553 : /*--------------- all but last block: aligned reads and different mixing */
554 10 : while (length > 12)
555 : {
556 0 : a += k[0] + (((uint32_t)k[1])<<16);
557 0 : b += k[2] + (((uint32_t)k[3])<<16);
558 0 : c += k[4] + (((uint32_t)k[5])<<16);
559 0 : mix(a,b,c);
560 0 : length -= 12;
561 0 : k += 6;
562 : }
563 :
564 : /*----------------------------- handle the last (probably partial) block */
565 5 : k8 = (const uint8_t *)k;
566 5 : switch(length)
567 : {
568 0 : case 12: c+=k[4]+(((uint32_t)k[5])<<16);
569 0 : b+=k[2]+(((uint32_t)k[3])<<16);
570 0 : a+=k[0]+(((uint32_t)k[1])<<16);
571 0 : break;
572 0 : case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
573 1 : case 10: c+=k[4];
574 1 : b+=k[2]+(((uint32_t)k[3])<<16);
575 1 : a+=k[0]+(((uint32_t)k[1])<<16);
576 1 : break;
577 1 : case 9 : c+=k8[8]; /* fall through */
578 1 : case 8 : b+=k[2]+(((uint32_t)k[3])<<16);
579 1 : a+=k[0]+(((uint32_t)k[1])<<16);
580 1 : break;
581 0 : case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
582 1 : case 6 : b+=k[2];
583 1 : a+=k[0]+(((uint32_t)k[1])<<16);
584 1 : break;
585 1 : case 5 : b+=k8[4]; /* fall through */
586 2 : case 4 : a+=k[0]+(((uint32_t)k[1])<<16);
587 2 : break;
588 0 : case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
589 0 : case 2 : a+=k[0];
590 0 : break;
591 0 : case 1 : a+=k8[0];
592 0 : break;
593 0 : case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
594 : }
595 :
596 : } else { /* need to read the key one byte at a time */
597 16 : const uint8_t *k = (const uint8_t *)key;
598 :
599 : /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
600 32 : while (length > 12)
601 : {
602 0 : a += k[0];
603 0 : a += ((uint32_t)k[1])<<8;
604 0 : a += ((uint32_t)k[2])<<16;
605 0 : a += ((uint32_t)k[3])<<24;
606 0 : b += k[4];
607 0 : b += ((uint32_t)k[5])<<8;
608 0 : b += ((uint32_t)k[6])<<16;
609 0 : b += ((uint32_t)k[7])<<24;
610 0 : c += k[8];
611 0 : c += ((uint32_t)k[9])<<8;
612 0 : c += ((uint32_t)k[10])<<16;
613 0 : c += ((uint32_t)k[11])<<24;
614 0 : mix(a,b,c);
615 0 : length -= 12;
616 0 : k += 12;
617 : }
618 :
619 : /*-------------------------------- last block: affect all 32 bits of (c) */
620 16 : switch(length) /* all the case statements fall through */
621 : {
622 0 : case 12: c+=((uint32_t)k[11])<<24;
623 2 : case 11: c+=((uint32_t)k[10])<<16;
624 6 : case 10: c+=((uint32_t)k[9])<<8;
625 10 : case 9 : c+=k[8];
626 12 : case 8 : b+=((uint32_t)k[7])<<24;
627 15 : case 7 : b+=((uint32_t)k[6])<<16;
628 16 : case 6 : b+=((uint32_t)k[5])<<8;
629 16 : case 5 : b+=k[4];
630 16 : case 4 : a+=((uint32_t)k[3])<<24;
631 16 : case 3 : a+=((uint32_t)k[2])<<16;
632 16 : case 2 : a+=((uint32_t)k[1])<<8;
633 16 : case 1 : a+=k[0];
634 16 : break;
635 0 : case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
636 : }
637 : }
638 :
639 170724 : final(a,b,c);
640 170724 : *pc=c; *pb=b;
641 : }
642 :
643 :
644 :
645 : /*
646 : * hashbig():
647 : * This is the same as hashword() on big-endian machines. It is different
648 : * from hashlittle() on all machines. hashbig() takes advantage of
649 : * big-endian byte ordering.
650 : */
651 0 : uint32_t jenkins_hashbig( const void *key, size_t length, uint32_t initval)
652 : {
653 : uint32_t a,b,c;
654 : union { const void *ptr; size_t i; } u; /* to cast key to (size_t) happily */
655 :
656 : /* Set up the internal state */
657 0 : a = b = c = 0xdeadbeef + ((uint32_t)length) + initval;
658 :
659 0 : u.ptr = key;
660 : if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
661 : const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
662 :
663 : /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
664 : while (length > 12)
665 : {
666 : a += k[0];
667 : b += k[1];
668 : c += k[2];
669 : mix(a,b,c);
670 : length -= 12;
671 : k += 3;
672 : }
673 :
674 : /*----------------------------- handle the last (probably partial) block */
675 : /*
676 : * "k[2]<<8" actually reads beyond the end of the string, but
677 : * then shifts out the part it's not allowed to read. Because the
678 : * string is aligned, the illegal read is in the same word as the
679 : * rest of the string. Every machine with memory protection I've seen
680 : * does it on word boundaries, so is OK with this. But VALGRIND will
681 : * still catch it and complain. The masking trick does make the hash
682 : * noticeably faster for short strings (like English words).
683 : */
684 : #ifndef VALGRIND
685 :
686 : switch(length)
687 : {
688 : case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
689 : case 11: c+=k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
690 : case 10: c+=k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
691 : case 9 : c+=k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
692 : case 8 : b+=k[1]; a+=k[0]; break;
693 : case 7 : b+=k[1]&0xffffff00; a+=k[0]; break;
694 : case 6 : b+=k[1]&0xffff0000; a+=k[0]; break;
695 : case 5 : b+=k[1]&0xff000000; a+=k[0]; break;
696 : case 4 : a+=k[0]; break;
697 : case 3 : a+=k[0]&0xffffff00; break;
698 : case 2 : a+=k[0]&0xffff0000; break;
699 : case 1 : a+=k[0]&0xff000000; break;
700 : case 0 : return c; /* zero length strings require no mixing */
701 : }
702 :
703 : #else /* make valgrind happy */
704 :
705 : {
706 : const uint8_t *k8 = (const uint8_t *)k;
707 : switch(length) /* all the case statements fall through */
708 : {
709 : case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
710 : case 11: c+=((uint32_t)k8[10])<<8; /* fall through */
711 : case 10: c+=((uint32_t)k8[9])<<16; /* fall through */
712 : case 9 : c+=((uint32_t)k8[8])<<24; /* fall through */
713 : case 8 : b+=k[1]; a+=k[0]; break;
714 : case 7 : b+=((uint32_t)k8[6])<<8; /* fall through */
715 : case 6 : b+=((uint32_t)k8[5])<<16; /* fall through */
716 : case 5 : b+=((uint32_t)k8[4])<<24; /* fall through */
717 : case 4 : a+=k[0]; break;
718 : case 3 : a+=((uint32_t)k8[2])<<8; /* fall through */
719 : case 2 : a+=((uint32_t)k8[1])<<16; /* fall through */
720 : case 1 : a+=((uint32_t)k8[0])<<24; break;
721 : case 0 : return c;
722 : }
723 : }
724 :
725 : #endif /* !VALGRIND */
726 :
727 : } else { /* need to read the key one byte at a time */
728 0 : const uint8_t *k = (const uint8_t *)key;
729 :
730 : /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
731 0 : while (length > 12)
732 : {
733 0 : a += ((uint32_t)k[0])<<24;
734 0 : a += ((uint32_t)k[1])<<16;
735 0 : a += ((uint32_t)k[2])<<8;
736 0 : a += ((uint32_t)k[3]);
737 0 : b += ((uint32_t)k[4])<<24;
738 0 : b += ((uint32_t)k[5])<<16;
739 0 : b += ((uint32_t)k[6])<<8;
740 0 : b += ((uint32_t)k[7]);
741 0 : c += ((uint32_t)k[8])<<24;
742 0 : c += ((uint32_t)k[9])<<16;
743 0 : c += ((uint32_t)k[10])<<8;
744 0 : c += ((uint32_t)k[11]);
745 0 : mix(a,b,c);
746 0 : length -= 12;
747 0 : k += 12;
748 : }
749 :
750 : /*-------------------------------- last block: affect all 32 bits of (c) */
751 0 : switch(length) /* all the case statements fall through */
752 : {
753 0 : case 12: c+=k[11];
754 0 : case 11: c+=((uint32_t)k[10])<<8;
755 0 : case 10: c+=((uint32_t)k[9])<<16;
756 0 : case 9 : c+=((uint32_t)k[8])<<24;
757 0 : case 8 : b+=k[7];
758 0 : case 7 : b+=((uint32_t)k[6])<<8;
759 0 : case 6 : b+=((uint32_t)k[5])<<16;
760 0 : case 5 : b+=((uint32_t)k[4])<<24;
761 0 : case 4 : a+=k[3];
762 0 : case 3 : a+=((uint32_t)k[2])<<8;
763 0 : case 2 : a+=((uint32_t)k[1])<<16;
764 0 : case 1 : a+=((uint32_t)k[0])<<24;
765 0 : break;
766 0 : case 0 : return c;
767 : }
768 : }
769 :
770 0 : final(a,b,c);
771 0 : return c;
772 : }
773 :
774 :
775 : #ifdef SELF_TEST
776 :
777 : /* used for timings */
778 : void driver1()
779 : {
780 : uint8_t buf[256];
781 : uint32_t i;
782 : uint32_t h=0;
783 : time_t a,z;
784 :
785 : time(&a);
786 : for (i=0; i<256; ++i) buf[i] = 'x';
787 : for (i=0; i<1; ++i)
788 : {
789 : h = hashlittle(&buf[0],1,h);
790 : }
791 : time(&z);
792 : if (z-a > 0) printf("time %d %.8x\n", z-a, h);
793 : }
794 :
795 : /* check that every input bit changes every output bit half the time */
796 : #define HASHSTATE 1
797 : #define HASHLEN 1
798 : #define MAXPAIR 60
799 : #define MAXLEN 70
800 : void driver2()
801 : {
802 : uint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1];
803 : uint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z;
804 : uint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE];
805 : uint32_t x[HASHSTATE],y[HASHSTATE];
806 : uint32_t hlen;
807 :
808 : printf("No more than %d trials should ever be needed \n",MAXPAIR/2);
809 : for (hlen=0; hlen < MAXLEN; ++hlen)
810 : {
811 : z=0;
812 : for (i=0; i<hlen; ++i) /*----------------------- for each input byte, */
813 : {
814 : for (j=0; j<8; ++j) /*------------------------ for each input bit, */
815 : {
816 : for (m=1; m<8; ++m) /*------------ for serveral possible initvals, */
817 : {
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 : {
824 : uint32_t finished=1;
825 : /* keys have one bit different */
826 : for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (uint8_t)0;}
827 : /* have a and b be two keys differing in only one bit */
828 : a[i] ^= (k<<j);
829 : a[i] ^= (k>>(8-j));
830 : c[0] = hashlittle(a, hlen, m);
831 : b[i] ^= ((k+1)<<j);
832 : b[i] ^= ((k+1)>>(8-j));
833 : d[0] = hashlittle(b, hlen, m);
834 : /* check every bit is 1, 0, set, and not set at least once */
835 : for (l=0; l<HASHSTATE; ++l)
836 : {
837 : e[l] &= (c[l]^d[l]);
838 : f[l] &= ~(c[l]^d[l]);
839 : g[l] &= c[l];
840 : h[l] &= ~c[l];
841 : x[l] &= d[l];
842 : y[l] &= ~d[l];
843 : if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0;
844 : }
845 : if (finished) break;
846 : }
847 : if (k>z) z=k;
848 : if (k==MAXPAIR)
849 : {
850 : printf("Some bit didn't change: ");
851 : printf("%.8x %.8x %.8x %.8x %.8x %.8x ",
852 : e[0],f[0],g[0],h[0],x[0],y[0]);
853 : printf("i %d j %d m %d len %d\n", i, j, m, hlen);
854 : }
855 : if (z==MAXPAIR) goto done;
856 : }
857 : }
858 : }
859 : done:
860 : if (z < MAXPAIR)
861 : {
862 : printf("Mix success %2d bytes %2d initvals ",i,m);
863 : printf("required %d trials\n", z/2);
864 : }
865 : }
866 : printf("\n");
867 : }
868 :
869 : /* Check for reading beyond the end of the buffer and alignment problems */
870 : void driver3()
871 : {
872 : uint8_t buf[MAXLEN+20], *b;
873 : uint32_t len;
874 : uint8_t q[] = "This is the time for all good men to come to the aid of their country...";
875 : uint32_t h;
876 : uint8_t qq[] = "xThis is the time for all good men to come to the aid of their country...";
877 : uint32_t i;
878 : uint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country...";
879 : uint32_t j;
880 : uint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country...";
881 : uint32_t ref,x,y;
882 : uint8_t *p;
883 :
884 : printf("Endianness. These lines should all be the same (for values filled in):\n");
885 : printf("%.8x %.8x %.8x\n",
886 : hashword((const uint32_t *)q, (sizeof(q)-1)/4, 13),
887 : hashword((const uint32_t *)q, (sizeof(q)-5)/4, 13),
888 : hashword((const uint32_t *)q, (sizeof(q)-9)/4, 13));
889 : p = q;
890 : printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
891 : hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
892 : hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
893 : hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
894 : hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
895 : hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
896 : hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
897 : p = &qq[1];
898 : printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
899 : hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
900 : hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
901 : hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
902 : hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
903 : hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
904 : hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
905 : p = &qqq[2];
906 : printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
907 : hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
908 : hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
909 : hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
910 : hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
911 : hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
912 : hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
913 : p = &qqqq[3];
914 : printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
915 : hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
916 : hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
917 : hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
918 : hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
919 : hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
920 : hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
921 : printf("\n");
922 :
923 : /* check that hashlittle2 and hashlittle produce the same results */
924 : i=47; j=0;
925 : hashlittle2(q, sizeof(q), &i, &j);
926 : if (hashlittle(q, sizeof(q), 47) != i)
927 : printf("hashlittle2 and hashlittle mismatch\n");
928 :
929 : /* check that hashword2 and hashword produce the same results */
930 : len = 0xdeadbeef;
931 : i=47, j=0;
932 : hashword2(&len, 1, &i, &j);
933 : if (hashword(&len, 1, 47) != i)
934 : printf("hashword2 and hashword mismatch %x %x\n",
935 : i, hashword(&len, 1, 47));
936 :
937 : /* check hashlittle doesn't read before or after the ends of the string */
938 : for (h=0, b=buf+1; h<8; ++h, ++b)
939 : {
940 : for (i=0; i<MAXLEN; ++i)
941 : {
942 : len = i;
943 : for (j=0; j<i; ++j) *(b+j)=0;
944 :
945 : /* these should all be equal */
946 : ref = hashlittle(b, len, (uint32_t)1);
947 : *(b+i)=(uint8_t)~0;
948 : *(b-1)=(uint8_t)~0;
949 : x = hashlittle(b, len, (uint32_t)1);
950 : y = hashlittle(b, len, (uint32_t)1);
951 : if ((ref != x) || (ref != y))
952 : {
953 : printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y,
954 : h, i);
955 : }
956 : }
957 : }
958 : }
959 :
960 : /* check for problems with nulls */
961 : void driver4()
962 : {
963 : uint8_t buf[1];
964 : uint32_t h,i,state[HASHSTATE];
965 :
966 :
967 : buf[0] = ~0;
968 : for (i=0; i<HASHSTATE; ++i) state[i] = 1;
969 : printf("These should all be different\n");
970 : for (i=0, h=0; i<8; ++i)
971 : {
972 : h = hashlittle(buf, 0, h);
973 : printf("%2ld 0-byte strings, hash is %.8x\n", i, h);
974 : }
975 : }
976 :
977 : void driver5()
978 : {
979 : uint32_t b,c;
980 : b=0, c=0, hashlittle2("", 0, &c, &b);
981 : printf("hash is %.8lx %.8lx\n", c, b); /* deadbeef deadbeef */
982 : b=0xdeadbeef, c=0, hashlittle2("", 0, &c, &b);
983 : printf("hash is %.8lx %.8lx\n", c, b); /* bd5b7dde deadbeef */
984 : b=0xdeadbeef, c=0xdeadbeef, hashlittle2("", 0, &c, &b);
985 : printf("hash is %.8lx %.8lx\n", c, b); /* 9c093ccd bd5b7dde */
986 : b=0, c=0, hashlittle2("Four score and seven years ago", 30, &c, &b);
987 : printf("hash is %.8lx %.8lx\n", c, b); /* 17770551 ce7226e6 */
988 : b=1, c=0, hashlittle2("Four score and seven years ago", 30, &c, &b);
989 : printf("hash is %.8lx %.8lx\n", c, b); /* e3607cae bd371de4 */
990 : b=0, c=1, hashlittle2("Four score and seven years ago", 30, &c, &b);
991 : printf("hash is %.8lx %.8lx\n", c, b); /* cd628161 6cbea4b3 */
992 : c = hashlittle("Four score and seven years ago", 30, 0);
993 : printf("hash is %.8lx\n", c); /* 17770551 */
994 : c = hashlittle("Four score and seven years ago", 30, 1);
995 : printf("hash is %.8lx\n", c); /* cd628161 */
996 : }
997 :
998 :
999 : int main()
1000 : {
1001 : driver1(); /* test that the key is hashed: used for timings */
1002 : driver2(); /* test that whole key is hashed thoroughly */
1003 : driver3(); /* test that nothing but the key is hashed */
1004 : driver4(); /* test hashing multiple buffers (all buffers are null) */
1005 : driver5(); /* test the hash against known vectors */
1006 : return 1;
1007 : }
1008 :
1009 : #endif /* SELF_TEST */
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