1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969
|
/* -------------------------------------------------------------------- */
/*
* lookup3.c, by Bob Jenkins, May 2006, Public Domain.
*
* These are functions for producing 32-bit hashes for hash table lookup.
* jlu32w(), jlu32l(), jlu32lpair(), jlu32b(), _JLU3_MIX(), and _JLU3_FINAL()
* are externally useful functions. Routines to test the hash are included
* if SELF_TEST is defined. You can use this free for any purpose. It's in
* the public domain. It has no warranty.
*
* You probably want to use jlu32l(). jlu32l() and jlu32b()
* hash byte arrays. jlu32l() is is faster than jlu32b() on
* little-endian machines. Intel and AMD are little-endian machines.
* On second thought, you probably want jlu32lpair(), which is identical to
* jlu32l() except it returns two 32-bit hashes for the price of one.
* You could implement jlu32bpair() if you wanted but I haven't bothered here.
*
* If you want to find a hash of, say, exactly 7 integers, do
* a = i1; b = i2; c = i3;
* _JLU3_MIX(a,b,c);
* a += i4; b += i5; c += i6;
* _JLU3_MIX(a,b,c);
* a += i7;
* _JLU3_FINAL(a,b,c);
* then use c as the hash value. If you have a variable size array of
* 4-byte integers to hash, use jlu32w(). If you have a byte array (like
* a character string), use jlu32l(). If you have several byte arrays, or
* a mix of things, see the comments above jlu32l().
*
* Why is this so big? I read 12 bytes at a time into 3 4-byte integers,
* then mix those integers. This is fast (you can do a lot more thorough
* mixing with 12*3 instructions on 3 integers than you can with 3 instructions
* on 1 byte), but shoehorning those bytes into integers efficiently is messy.
*/
/* -------------------------------------------------------------------- */
#include <stdint.h>
#if defined(_JLU3_SELFTEST)
# define _JLU3_jlu32w 1
# define _JLU3_jlu32l 1
# define _JLU3_jlu32lpair 1
# define _JLU3_jlu32b 1
#endif
/*@-redef@*/
/*@unchecked@*/
static const union _dbswap {
const uint32_t ui;
const unsigned char uc[4];
} endian = { .ui = 0x11223344 };
# define HASH_LITTLE_ENDIAN (endian.uc[0] == (unsigned char) 0x44)
# define HASH_BIG_ENDIAN (endian.uc[0] == (unsigned char) 0x11)
/*@=redef@*/
#ifndef ROTL32
# define ROTL32(x, s) (((x) << (s)) | ((x) >> (32 - (s))))
#endif
/* NOTE: The _size parameter should be in bytes. */
#define _JLU3_INIT(_h, _size) (0xdeadbeef + ((uint32_t)(_size)) + (_h))
/* -------------------------------------------------------------------- */
/*
* _JLU3_MIX -- mix 3 32-bit values reversibly.
*
* This is reversible, so any information in (a,b,c) before _JLU3_MIX() is
* still in (a,b,c) after _JLU3_MIX().
*
* If four pairs of (a,b,c) inputs are run through _JLU3_MIX(), or through
* _JLU3_MIX() in reverse, there are at least 32 bits of the output that
* are sometimes the same for one pair and different for another pair.
* This was tested for:
* * pairs that differed by one bit, by two bits, in any combination
* of top bits of (a,b,c), or in any combination of bottom bits of
* (a,b,c).
* * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
* the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
* is commonly produced by subtraction) look like a single 1-bit
* difference.
* * the base values were pseudorandom, all zero but one bit set, or
* all zero plus a counter that starts at zero.
*
* Some k values for my "a-=c; a^=ROTL32(c,k); c+=b;" arrangement that
* satisfy this are
* 4 6 8 16 19 4
* 9 15 3 18 27 15
* 14 9 3 7 17 3
* Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
* for "differ" defined as + with a one-bit base and a two-bit delta. I
* used http://burtleburtle.net/bob/hash/avalanche.html to choose
* the operations, constants, and arrangements of the variables.
*
* This does not achieve avalanche. There are input bits of (a,b,c)
* that fail to affect some output bits of (a,b,c), especially of a. The
* most thoroughly mixed value is c, but it doesn't really even achieve
* avalanche in c.
*
* This allows some parallelism. Read-after-writes are good at doubling
* the number of bits affected, so the goal of mixing pulls in the opposite
* direction as the goal of parallelism. I did what I could. Rotates
* seem to cost as much as shifts on every machine I could lay my hands
* on, and rotates are much kinder to the top and bottom bits, so I used
* rotates.
*/
/* -------------------------------------------------------------------- */
#define _JLU3_MIX(a,b,c) \
{ \
a -= c; a ^= ROTL32(c, 4); c += b; \
b -= a; b ^= ROTL32(a, 6); a += c; \
c -= b; c ^= ROTL32(b, 8); b += a; \
a -= c; a ^= ROTL32(c,16); c += b; \
b -= a; b ^= ROTL32(a,19); a += c; \
c -= b; c ^= ROTL32(b, 4); b += a; \
}
/* -------------------------------------------------------------------- */
/**
* _JLU3_FINAL -- final mixing of 3 32-bit values (a,b,c) into c
*
* Pairs of (a,b,c) values differing in only a few bits will usually
* produce values of c that look totally different. This was tested for
* * pairs that differed by one bit, by two bits, in any combination
* of top bits of (a,b,c), or in any combination of bottom bits of
* (a,b,c).
* * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
* the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
* is commonly produced by subtraction) look like a single 1-bit
* difference.
* * the base values were pseudorandom, all zero but one bit set, or
* all zero plus a counter that starts at zero.
*
* These constants passed:
* 14 11 25 16 4 14 24
* 12 14 25 16 4 14 24
* and these came close:
* 4 8 15 26 3 22 24
* 10 8 15 26 3 22 24
* 11 8 15 26 3 22 24
*/
/* -------------------------------------------------------------------- */
#define _JLU3_FINAL(a,b,c) \
{ \
c ^= b; c -= ROTL32(b,14); \
a ^= c; a -= ROTL32(c,11); \
b ^= a; b -= ROTL32(a,25); \
c ^= b; c -= ROTL32(b,16); \
a ^= c; a -= ROTL32(c,4); \
b ^= a; b -= ROTL32(a,14); \
c ^= b; c -= ROTL32(b,24); \
}
#if defined(_JLU3_jlu32w)
uint32_t jlu32w(uint32_t h, /*@null@*/ const uint32_t *k, size_t size)
/*@*/;
/* -------------------------------------------------------------------- */
/**
* This works on all machines. To be useful, it requires
* -- that the key be an array of uint32_t's, and
* -- that the size be the number of uint32_t's in the key
*
* The function jlu32w() is identical to jlu32l() on little-endian
* machines, and identical to jlu32b() on big-endian machines,
* except that the size has to be measured in uint32_ts rather than in
* bytes. jlu32l() is more complicated than jlu32w() only because
* jlu32l() has to dance around fitting the key bytes into registers.
*
* @param h the previous hash, or an arbitrary value
* @param *k the key, an array of uint32_t values
* @param size the size of the key, in uint32_ts
* @return the lookup3 hash
*/
/* -------------------------------------------------------------------- */
uint32_t jlu32w(uint32_t h, const uint32_t *k, size_t size)
{
uint32_t a = _JLU3_INIT(h, (size * sizeof(*k)));
uint32_t b = a;
uint32_t c = a;
if (k == NULL)
goto exit;
/*----------------------------------------------- handle most of the key */
while (size > 3) {
a += k[0];
b += k[1];
c += k[2];
_JLU3_MIX(a,b,c);
size -= 3;
k += 3;
}
/*----------------------------------------- handle the last 3 uint32_t's */
switch (size) {
case 3 : c+=k[2];
case 2 : b+=k[1];
case 1 : a+=k[0];
_JLU3_FINAL(a,b,c);
/*@fallthrough@*/
case 0:
break;
}
/*---------------------------------------------------- report the result */
exit:
return c;
}
#endif /* defined(_JLU3_jlu32w) */
#if defined(_JLU3_jlu32l)
uint32_t jlu32l(uint32_t h, const void *key, size_t size)
/*@*/;
/* -------------------------------------------------------------------- */
/*
* jlu32l() -- hash a variable-length key into a 32-bit value
* h : can be any 4-byte value
* k : the key (the unaligned variable-length array of bytes)
* size : the size of the key, counting by bytes
* Returns a 32-bit value. Every bit of the key affects every bit of
* the return value. Two keys differing by one or two bits will have
* totally different hash values.
*
* The best hash table sizes are powers of 2. There is no need to do
* mod a prime (mod is sooo slow!). If you need less than 32 bits,
* use a bitmask. For example, if you need only 10 bits, do
* h = (h & hashmask(10));
* In which case, the hash table should have hashsize(10) elements.
*
* If you are hashing n strings (uint8_t **)k, do it like this:
* for (i=0, h=0; i<n; ++i) h = jlu32l(h, k[i], len[i]);
*
* By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this
* code any way you wish, private, educational, or commercial. It's free.
*
* Use for hash table lookup, or anything where one collision in 2^^32 is
* acceptable. Do NOT use for cryptographic purposes.
*
* @param h the previous hash, or an arbitrary value
* @param *k the key, an array of uint8_t values
* @param size the size of the key
* @return the lookup3 hash
*/
/* -------------------------------------------------------------------- */
uint32_t jlu32l(uint32_t h, const void *key, size_t size)
{
union { const void *ptr; size_t i; } u;
uint32_t a = _JLU3_INIT(h, size);
uint32_t b = a;
uint32_t c = a;
if (key == NULL)
goto exit;
u.ptr = key;
if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
#ifdef VALGRIND
const uint8_t *k8;
#endif
/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
while (size > 12) {
a += k[0];
b += k[1];
c += k[2];
_JLU3_MIX(a,b,c);
size -= 12;
k += 3;
}
/*------------------------- handle the last (probably partial) block */
/*
* "k[2]&0xffffff" actually reads beyond the end of the string, but
* then masks off the part it's not allowed to read. Because the
* string is aligned, the masked-off tail is in the same word as the
* rest of the string. Every machine with memory protection I've seen
* does it on word boundaries, so is OK with this. But VALGRIND will
* still catch it and complain. The masking trick does make the hash
* noticably faster for short strings (like English words).
*/
#ifndef VALGRIND
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
case 10: c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
case 9: c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
case 8: b += k[1]; a+=k[0]; break;
case 7: b += k[1]&0xffffff; a+=k[0]; break;
case 6: b += k[1]&0xffff; a+=k[0]; break;
case 5: b += k[1]&0xff; a+=k[0]; break;
case 4: a += k[0]; break;
case 3: a += k[0]&0xffffff; break;
case 2: a += k[0]&0xffff; break;
case 1: a += k[0]&0xff; break;
case 0: goto exit;
}
#else /* make valgrind happy */
k8 = (const uint8_t *)k;
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0] break;
case 11: c += ((uint32_t)k8[10])<<16; /*@fallthrough@*/
case 10: c += ((uint32_t)k8[9])<<8; /*@fallthrough@*/
case 9: c += k8[8]; /*@fallthrough@*/
case 8: b += k[1]; a+=k[0]; break;
case 7: b += ((uint32_t)k8[6])<<16; /*@fallthrough@*/
case 6: b += ((uint32_t)k8[5])<<8; /*@fallthrough@*/
case 5: b += k8[4]; /*@fallthrough@*/
case 4: a += k[0]; break;
case 3: a += ((uint32_t)k8[2])<<16; /*@fallthrough@*/
case 2: a += ((uint32_t)k8[1])<<8; /*@fallthrough@*/
case 1: a += k8[0]; break;
case 0: goto exit;
}
#endif /* !valgrind */
} else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
const uint8_t *k8;
/*----------- all but last block: aligned reads and different mixing */
while (size > 12) {
a += k[0] + (((uint32_t)k[1])<<16);
b += k[2] + (((uint32_t)k[3])<<16);
c += k[4] + (((uint32_t)k[5])<<16);
_JLU3_MIX(a,b,c);
size -= 12;
k += 6;
}
/*------------------------- handle the last (probably partial) block */
k8 = (const uint8_t *)k;
switch (size) {
case 12:
c += k[4]+(((uint32_t)k[5])<<16);
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 11:
c += ((uint32_t)k8[10])<<16;
/*@fallthrough@*/
case 10:
c += (uint32_t)k[4];
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 9:
c += (uint32_t)k8[8];
/*@fallthrough@*/
case 8:
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 7:
b += ((uint32_t)k8[6])<<16;
/*@fallthrough@*/
case 6:
b += (uint32_t)k[2];
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 5:
b += (uint32_t)k8[4];
/*@fallthrough@*/
case 4:
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 3:
a += ((uint32_t)k8[2])<<16;
/*@fallthrough@*/
case 2:
a += (uint32_t)k[0];
break;
case 1:
a += (uint32_t)k8[0];
break;
case 0:
goto exit;
}
} else { /* need to read the key one byte at a time */
const uint8_t *k = (const uint8_t *)key;
/*----------- all but the last block: affect some 32 bits of (a,b,c) */
while (size > 12) {
a += (uint32_t)k[0];
a += ((uint32_t)k[1])<<8;
a += ((uint32_t)k[2])<<16;
a += ((uint32_t)k[3])<<24;
b += (uint32_t)k[4];
b += ((uint32_t)k[5])<<8;
b += ((uint32_t)k[6])<<16;
b += ((uint32_t)k[7])<<24;
c += (uint32_t)k[8];
c += ((uint32_t)k[9])<<8;
c += ((uint32_t)k[10])<<16;
c += ((uint32_t)k[11])<<24;
_JLU3_MIX(a,b,c);
size -= 12;
k += 12;
}
/*---------------------------- last block: affect all 32 bits of (c) */
switch (size) {
case 12: c += ((uint32_t)k[11])<<24; /*@fallthrough@*/
case 11: c += ((uint32_t)k[10])<<16; /*@fallthrough@*/
case 10: c += ((uint32_t)k[9])<<8; /*@fallthrough@*/
case 9: c += (uint32_t)k[8]; /*@fallthrough@*/
case 8: b += ((uint32_t)k[7])<<24; /*@fallthrough@*/
case 7: b += ((uint32_t)k[6])<<16; /*@fallthrough@*/
case 6: b += ((uint32_t)k[5])<<8; /*@fallthrough@*/
case 5: b += (uint32_t)k[4]; /*@fallthrough@*/
case 4: a += ((uint32_t)k[3])<<24; /*@fallthrough@*/
case 3: a += ((uint32_t)k[2])<<16; /*@fallthrough@*/
case 2: a += ((uint32_t)k[1])<<8; /*@fallthrough@*/
case 1: a += (uint32_t)k[0];
break;
case 0:
goto exit;
}
}
_JLU3_FINAL(a,b,c);
exit:
return c;
}
#endif /* defined(_JLU3_jlu32l) */
#if defined(_JLU3_jlu32lpair)
/**
* jlu32lpair: return 2 32-bit hash values.
*
* This is identical to jlu32l(), except it returns two 32-bit hash
* values instead of just one. This is good enough for hash table
* lookup with 2^^64 buckets, or if you want a second hash if you're not
* happy with the first, or if you want a probably-unique 64-bit ID for
* the key. *pc is better mixed than *pb, so use *pc first. If you want
* a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
*
* @param h the previous hash, or an arbitrary value
* @param *key the key, an array of uint8_t values
* @param size the size of the key in bytes
* @retval *pc, IN: primary initval, OUT: primary hash
* *retval *pb IN: secondary initval, OUT: secondary hash
*/
void jlu32lpair(const void *key, size_t size, uint32_t *pc, uint32_t *pb)
{
union { const void *ptr; size_t i; } u;
uint32_t a = _JLU3_INIT(*pc, size);
uint32_t b = a;
uint32_t c = a;
if (key == NULL)
goto exit;
c += *pb; /* Add the secondary hash. */
u.ptr = key;
if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
#ifdef VALGRIND
const uint8_t *k8;
#endif
/*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
while (size > (size_t)12) {
a += k[0];
b += k[1];
c += k[2];
_JLU3_MIX(a,b,c);
size -= 12;
k += 3;
}
/*------------------------- handle the last (probably partial) block */
/*
* "k[2]&0xffffff" actually reads beyond the end of the string, but
* then masks off the part it's not allowed to read. Because the
* string is aligned, the masked-off tail is in the same word as the
* rest of the string. Every machine with memory protection I've seen
* does it on word boundaries, so is OK with this. But VALGRIND will
* still catch it and complain. The masking trick does make the hash
* noticably faster for short strings (like English words).
*/
#ifndef VALGRIND
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
case 10: c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
case 9: c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
case 8: b += k[1]; a+=k[0]; break;
case 7: b += k[1]&0xffffff; a+=k[0]; break;
case 6: b += k[1]&0xffff; a+=k[0]; break;
case 5: b += k[1]&0xff; a+=k[0]; break;
case 4: a += k[0]; break;
case 3: a += k[0]&0xffffff; break;
case 2: a += k[0]&0xffff; break;
case 1: a += k[0]&0xff; break;
case 0: goto exit;
}
#else /* make valgrind happy */
k8 = (const uint8_t *)k;
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += ((uint32_t)k8[10])<<16; /*@fallthrough@*/
case 10: c += ((uint32_t)k8[9])<<8; /*@fallthrough@*/
case 9: c += k8[8]; /*@fallthrough@*/
case 8: b += k[1]; a+=k[0]; break;
case 7: b += ((uint32_t)k8[6])<<16; /*@fallthrough@*/
case 6: b += ((uint32_t)k8[5])<<8; /*@fallthrough@*/
case 5: b += k8[4]; /*@fallthrough@*/
case 4: a += k[0]; break;
case 3: a += ((uint32_t)k8[2])<<16; /*@fallthrough@*/
case 2: a += ((uint32_t)k8[1])<<8; /*@fallthrough@*/
case 1: a += k8[0]; break;
case 0: goto exit;
}
#endif /* !valgrind */
} else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
const uint8_t *k8;
/*----------- all but last block: aligned reads and different mixing */
while (size > (size_t)12) {
a += k[0] + (((uint32_t)k[1])<<16);
b += k[2] + (((uint32_t)k[3])<<16);
c += k[4] + (((uint32_t)k[5])<<16);
_JLU3_MIX(a,b,c);
size -= 12;
k += 6;
}
/*------------------------- handle the last (probably partial) block */
k8 = (const uint8_t *)k;
switch (size) {
case 12:
c += k[4]+(((uint32_t)k[5])<<16);
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 11:
c += ((uint32_t)k8[10])<<16;
/*@fallthrough@*/
case 10:
c += k[4];
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 9:
c += k8[8];
/*@fallthrough@*/
case 8:
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 7:
b += ((uint32_t)k8[6])<<16;
/*@fallthrough@*/
case 6:
b += k[2];
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 5:
b += k8[4];
/*@fallthrough@*/
case 4:
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 3:
a += ((uint32_t)k8[2])<<16;
/*@fallthrough@*/
case 2:
a += k[0];
break;
case 1:
a += k8[0];
break;
case 0:
goto exit;
}
} else { /* need to read the key one byte at a time */
const uint8_t *k = (const uint8_t *)key;
/*----------- all but the last block: affect some 32 bits of (a,b,c) */
while (size > (size_t)12) {
a += k[0];
a += ((uint32_t)k[1])<<8;
a += ((uint32_t)k[2])<<16;
a += ((uint32_t)k[3])<<24;
b += k[4];
b += ((uint32_t)k[5])<<8;
b += ((uint32_t)k[6])<<16;
b += ((uint32_t)k[7])<<24;
c += k[8];
c += ((uint32_t)k[9])<<8;
c += ((uint32_t)k[10])<<16;
c += ((uint32_t)k[11])<<24;
_JLU3_MIX(a,b,c);
size -= 12;
k += 12;
}
/*---------------------------- last block: affect all 32 bits of (c) */
switch (size) {
case 12: c += ((uint32_t)k[11])<<24; /*@fallthrough@*/
case 11: c += ((uint32_t)k[10])<<16; /*@fallthrough@*/
case 10: c += ((uint32_t)k[9])<<8; /*@fallthrough@*/
case 9: c += k[8]; /*@fallthrough@*/
case 8: b += ((uint32_t)k[7])<<24; /*@fallthrough@*/
case 7: b += ((uint32_t)k[6])<<16; /*@fallthrough@*/
case 6: b += ((uint32_t)k[5])<<8; /*@fallthrough@*/
case 5: b += k[4]; /*@fallthrough@*/
case 4: a += ((uint32_t)k[3])<<24; /*@fallthrough@*/
case 3: a += ((uint32_t)k[2])<<16; /*@fallthrough@*/
case 2: a += ((uint32_t)k[1])<<8; /*@fallthrough@*/
case 1: a += k[0];
break;
case 0:
goto exit;
}
}
_JLU3_FINAL(a,b,c);
exit:
*pc = c;
*pb = b;
return;
}
#endif /* defined(_JLU3_jlu32lpair) */
#if defined(_JLU3_jlu32b)
uint32_t jlu32b(uint32_t h, /*@null@*/ const void *key, size_t size)
/*@*/;
/*
* jlu32b():
* This is the same as jlu32w() on big-endian machines. It is different
* from jlu32l() on all machines. jlu32b() takes advantage of
* big-endian byte ordering.
*
* @param h the previous hash, or an arbitrary value
* @param *k the key, an array of uint8_t values
* @param size the size of the key
* @return the lookup3 hash
*/
uint32_t jlu32b(uint32_t h, const void *key, size_t size)
{
union { const void *ptr; size_t i; } u;
uint32_t a = _JLU3_INIT(h, size);
uint32_t b = a;
uint32_t c = a;
if (key == NULL)
return h;
u.ptr = key;
if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
#ifdef VALGRIND
const uint8_t *k8;
#endif
/*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
while (size > 12) {
a += k[0];
b += k[1];
c += k[2];
_JLU3_MIX(a,b,c);
size -= 12;
k += 3;
}
/*------------------------- handle the last (probably partial) block */
/*
* "k[2]<<8" actually reads beyond the end of the string, but
* then shifts out the part it's not allowed to read. Because the
* string is aligned, the illegal read is in the same word as the
* rest of the string. Every machine with memory protection I've seen
* does it on word boundaries, so is OK with this. But VALGRIND will
* still catch it and complain. The masking trick does make the hash
* noticably faster for short strings (like English words).
*/
#ifndef VALGRIND
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
case 10: c += k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
case 9: c += k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
case 8: b += k[1]; a+=k[0]; break;
case 7: b += k[1]&0xffffff00; a+=k[0]; break;
case 6: b += k[1]&0xffff0000; a+=k[0]; break;
case 5: b += k[1]&0xff000000; a+=k[0]; break;
case 4: a += k[0]; break;
case 3: a += k[0]&0xffffff00; break;
case 2: a += k[0]&0xffff0000; break;
case 1: a += k[0]&0xff000000; break;
case 0: goto exit;
}
#else /* make valgrind happy */
k8 = (const uint8_t *)k;
switch (size) { /* all the case statements fall through */
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += ((uint32_t)k8[10])<<8; /*@fallthrough@*/
case 10: c += ((uint32_t)k8[9])<<16; /*@fallthrough@*/
case 9: c += ((uint32_t)k8[8])<<24; /*@fallthrough@*/
case 8: b += k[1]; a+=k[0]; break;
case 7: b += ((uint32_t)k8[6])<<8; /*@fallthrough@*/
case 6: b += ((uint32_t)k8[5])<<16; /*@fallthrough@*/
case 5: b += ((uint32_t)k8[4])<<24; /*@fallthrough@*/
case 4: a += k[0]; break;
case 3: a += ((uint32_t)k8[2])<<8; /*@fallthrough@*/
case 2: a += ((uint32_t)k8[1])<<16; /*@fallthrough@*/
case 1: a += ((uint32_t)k8[0])<<24; break;
case 0: goto exit;
}
#endif /* !VALGRIND */
} else { /* need to read the key one byte at a time */
const uint8_t *k = (const uint8_t *)key;
/*----------- all but the last block: affect some 32 bits of (a,b,c) */
while (size > 12) {
a += ((uint32_t)k[0])<<24;
a += ((uint32_t)k[1])<<16;
a += ((uint32_t)k[2])<<8;
a += ((uint32_t)k[3]);
b += ((uint32_t)k[4])<<24;
b += ((uint32_t)k[5])<<16;
b += ((uint32_t)k[6])<<8;
b += ((uint32_t)k[7]);
c += ((uint32_t)k[8])<<24;
c += ((uint32_t)k[9])<<16;
c += ((uint32_t)k[10])<<8;
c += ((uint32_t)k[11]);
_JLU3_MIX(a,b,c);
size -= 12;
k += 12;
}
/*---------------------------- last block: affect all 32 bits of (c) */
switch (size) { /* all the case statements fall through */
case 12: c += k[11]; /*@fallthrough@*/
case 11: c += ((uint32_t)k[10])<<8; /*@fallthrough@*/
case 10: c += ((uint32_t)k[9])<<16; /*@fallthrough@*/
case 9: c += ((uint32_t)k[8])<<24; /*@fallthrough@*/
case 8: b += k[7]; /*@fallthrough@*/
case 7: b += ((uint32_t)k[6])<<8; /*@fallthrough@*/
case 6: b += ((uint32_t)k[5])<<16; /*@fallthrough@*/
case 5: b += ((uint32_t)k[4])<<24; /*@fallthrough@*/
case 4: a += k[3]; /*@fallthrough@*/
case 3: a += ((uint32_t)k[2])<<8; /*@fallthrough@*/
case 2: a += ((uint32_t)k[1])<<16; /*@fallthrough@*/
case 1: a += ((uint32_t)k[0])<<24; /*@fallthrough@*/
break;
case 0:
goto exit;
}
}
_JLU3_FINAL(a,b,c);
exit:
return c;
}
#endif /* defined(_JLU3_jlu32b) */
#if defined(_JLU3_SELFTEST)
/* used for timings */
static void driver1(void)
/*@*/
{
uint8_t buf[256];
uint32_t i;
uint32_t h=0;
time_t a,z;
time(&a);
for (i=0; i<256; ++i) buf[i] = 'x';
for (i=0; i<1; ++i) {
h = jlu32l(h, &buf[0], sizeof(buf[0]));
}
time(&z);
if (z-a > 0) printf("time %d %.8x\n", (int)(z-a), h);
}
/* check that every input bit changes every output bit half the time */
#define HASHSTATE 1
#define HASHLEN 1
#define MAXPAIR 60
#define MAXLEN 70
static void driver2(void)
/*@*/
{
uint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1];
uint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z;
uint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE];
uint32_t x[HASHSTATE],y[HASHSTATE];
uint32_t hlen;
printf("No more than %d trials should ever be needed \n",MAXPAIR/2);
for (hlen=0; hlen < MAXLEN; ++hlen) {
z=0;
for (i=0; i<hlen; ++i) { /*-------------- for each input byte, */
for (j=0; j<8; ++j) { /*--------------- for each input bit, */
for (m=1; m<8; ++m) { /*--- for serveral possible initvals, */
for (l=0; l<HASHSTATE; ++l)
e[l]=f[l]=g[l]=h[l]=x[l]=y[l]=~((uint32_t)0);
/* check that every output bit is affected by that input bit */
for (k=0; k<MAXPAIR; k+=2) {
uint32_t finished=1;
/* keys have one bit different */
for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (uint8_t)0;}
/* have a and b be two keys differing in only one bit */
a[i] ^= (k<<j);
a[i] ^= (k>>(8-j));
c[0] = jlu32l(m, a, hlen);
b[i] ^= ((k+1)<<j);
b[i] ^= ((k+1)>>(8-j));
d[0] = jlu32l(m, b, hlen);
/* check every bit is 1, 0, set, and not set at least once */
for (l=0; l<HASHSTATE; ++l) {
e[l] &= (c[l]^d[l]);
f[l] &= ~(c[l]^d[l]);
g[l] &= c[l];
h[l] &= ~c[l];
x[l] &= d[l];
y[l] &= ~d[l];
if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0;
}
if (finished) break;
}
if (k>z) z=k;
if (k == MAXPAIR) {
printf("Some bit didn't change: ");
printf("%.8x %.8x %.8x %.8x %.8x %.8x ",
e[0],f[0],g[0],h[0],x[0],y[0]);
printf("i %d j %d m %d len %d\n", i, j, m, hlen);
}
if (z == MAXPAIR) goto done;
}
}
}
done:
if (z < MAXPAIR) {
printf("Mix success %2d bytes %2d initvals ",i,m);
printf("required %d trials\n", z/2);
}
}
printf("\n");
}
/* Check for reading beyond the end of the buffer and alignment problems */
static void driver3(void)
/*@*/
{
uint8_t buf[MAXLEN+20], *b;
uint32_t len;
uint8_t q[] = "This is the time for all good men to come to the aid of their country...";
uint32_t h;
uint8_t qq[] = "xThis is the time for all good men to come to the aid of their country...";
uint32_t i;
uint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country...";
uint32_t j;
uint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country...";
uint32_t ref,x,y;
uint8_t *p;
uint32_t m = 13;
printf("Endianness. These lines should all be the same (for values filled in):\n");
printf("%.8x %.8x %.8x\n",
jlu32w(m, (const uint32_t *)q, (sizeof(q)-1)/4),
jlu32w(m, (const uint32_t *)q, (sizeof(q)-5)/4),
jlu32w(m, (const uint32_t *)q, (sizeof(q)-9)/4));
p = q;
printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
p = &qq[1];
printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
p = &qqq[2];
printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
p = &qqqq[3];
printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
printf("\n");
for (h=0, b=buf+1; h<8; ++h, ++b) {
for (i=0; i<MAXLEN; ++i) {
len = i;
for (j=0; j<i; ++j)
*(b+j)=0;
/* these should all be equal */
m = 1;
ref = jlu32l(m, b, len);
*(b+i)=(uint8_t)~0;
*(b-1)=(uint8_t)~0;
x = jlu32l(m, b, len);
y = jlu32l(m, b, len);
if ((ref != x) || (ref != y))
printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y, h, i);
}
}
}
/* check for problems with nulls */
static void driver4(void)
/*@*/
{
uint8_t buf[1];
uint32_t h;
uint32_t i;
uint32_t state[HASHSTATE];
buf[0] = ~0;
for (i=0; i<HASHSTATE; ++i)
state[i] = 1;
printf("These should all be different\n");
h = 0;
for (i=0; i<8; ++i) {
h = jlu32l(h, buf, 0);
printf("%2ld 0-byte strings, hash is %.8x\n", (long)i, h);
}
}
int main(int argc, char ** argv)
{
driver1(); /* test that the key is hashed: used for timings */
driver2(); /* test that whole key is hashed thoroughly */
driver3(); /* test that nothing but the key is hashed */
driver4(); /* test hashing multiple buffers (all buffers are null) */
return 1;
}
#endif /* _JLU3_SELFTEST */
|