Annotation of embedaddon/coova-chilli/src/lookup3.c, revision 1.1
1.1 ! misho 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: hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and 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 hashlittle(). hashlittle() and hashbig()
! 12: hash byte arrays. hashlittle() is is faster than hashbig() on
! 13: little-endian machines. Intel and AMD are little-endian machines.
! 14: On second thought, you probably want hashlittle2(), which is identical to
! 15: hashlittle() except it returns two 32-bit hashes for the price of one.
! 16: You could implement hashbig2() 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: mix(a,b,c);
! 21: a += i4; b += i5; c += i6;
! 22: mix(a,b,c);
! 23: a += i7;
! 24: final(a,b,c);
! 25: then use c as the hash value. If you have a variable length array of
! 26: 4-byte integers to hash, use hashword(). If you have a byte array (like
! 27: a character string), use hashlittle(). If you have several byte arrays, or
! 28: a mix of things, see the comments above hashlittle().
! 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: #define SELF_TEST 1
! 36: */
! 37:
! 38: #include <stdio.h> /* defines printf for tests */
! 39: #include <time.h> /* defines time_t for timings in the test */
! 40: #include <stdint.h> /* defines uint32_t etc */
! 41: #include <sys/param.h> /* attempt to define endianness */
! 42: #ifdef linux
! 43: # include <endian.h> /* attempt to define endianness */
! 44: #endif
! 45:
! 46: /*
! 47: * My best guess at if you are big-endian or little-endian. This may
! 48: * need adjustment.
! 49: */
! 50: #if (defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && \
! 51: __BYTE_ORDER == __LITTLE_ENDIAN) || \
! 52: (defined(i386) || defined(__i386__) || defined(__i486__) || \
! 53: defined(__i586__) || defined(__i686__) || defined(vax) || defined(MIPSEL))
! 54: # define HASH_LITTLE_ENDIAN 1
! 55: # define HASH_BIG_ENDIAN 0
! 56: #elif (defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && \
! 57: __BYTE_ORDER == __BIG_ENDIAN) || \
! 58: (defined(sparc) || defined(POWERPC) || defined(mc68000) || defined(sel))
! 59: # define HASH_LITTLE_ENDIAN 0
! 60: # define HASH_BIG_ENDIAN 1
! 61: #else
! 62: # define HASH_LITTLE_ENDIAN 0
! 63: # define HASH_BIG_ENDIAN 0
! 64: #endif
! 65:
! 66: #define hashsize(n) ((uint32_t)1<<(n))
! 67: #define hashmask(n) (hashsize(n)-1)
! 68: #define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
! 69:
! 70: /*
! 71: -------------------------------------------------------------------------------
! 72: mix -- mix 3 32-bit values reversibly.
! 73:
! 74: This is reversible, so any information in (a,b,c) before mix() is
! 75: still in (a,b,c) after mix().
! 76:
! 77: If four pairs of (a,b,c) inputs are run through mix(), or through
! 78: mix() in reverse, there are at least 32 bits of the output that
! 79: are sometimes the same for one pair and different for another pair.
! 80: This was tested for:
! 81: * pairs that differed by one bit, by two bits, in any combination
! 82: of top bits of (a,b,c), or in any combination of bottom bits of
! 83: (a,b,c).
! 84: * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
! 85: the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
! 86: is commonly produced by subtraction) look like a single 1-bit
! 87: difference.
! 88: * the base values were pseudorandom, all zero but one bit set, or
! 89: all zero plus a counter that starts at zero.
! 90:
! 91: Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that
! 92: satisfy this are
! 93: 4 6 8 16 19 4
! 94: 9 15 3 18 27 15
! 95: 14 9 3 7 17 3
! 96: Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
! 97: for "differ" defined as + with a one-bit base and a two-bit delta. I
! 98: used http://burtleburtle.net/bob/hash/avalanche.html to choose
! 99: the operations, constants, and arrangements of the variables.
! 100:
! 101: This does not achieve avalanche. There are input bits of (a,b,c)
! 102: that fail to affect some output bits of (a,b,c), especially of a. The
! 103: most thoroughly mixed value is c, but it doesn't really even achieve
! 104: avalanche in c.
! 105:
! 106: This allows some parallelism. Read-after-writes are good at doubling
! 107: the number of bits affected, so the goal of mixing pulls in the opposite
! 108: direction as the goal of parallelism. I did what I could. Rotates
! 109: seem to cost as much as shifts on every machine I could lay my hands
! 110: on, and rotates are much kinder to the top and bottom bits, so I used
! 111: rotates.
! 112: -------------------------------------------------------------------------------
! 113: */
! 114: #define mix(a,b,c) \
! 115: { \
! 116: a -= c; a ^= rot(c, 4); c += b; \
! 117: b -= a; b ^= rot(a, 6); a += c; \
! 118: c -= b; c ^= rot(b, 8); b += a; \
! 119: a -= c; a ^= rot(c,16); c += b; \
! 120: b -= a; b ^= rot(a,19); a += c; \
! 121: c -= b; c ^= rot(b, 4); b += a; \
! 122: }
! 123:
! 124: /*
! 125: -------------------------------------------------------------------------------
! 126: final -- final mixing of 3 32-bit values (a,b,c) into c
! 127:
! 128: Pairs of (a,b,c) values differing in only a few bits will usually
! 129: produce values of c that look totally different. This was tested for
! 130: * pairs that differed by one bit, by two bits, in any combination
! 131: of top bits of (a,b,c), or in any combination of bottom bits of
! 132: (a,b,c).
! 133: * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
! 134: the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
! 135: is commonly produced by subtraction) look like a single 1-bit
! 136: difference.
! 137: * the base values were pseudorandom, all zero but one bit set, or
! 138: all zero plus a counter that starts at zero.
! 139:
! 140: These constants passed:
! 141: 14 11 25 16 4 14 24
! 142: 12 14 25 16 4 14 24
! 143: and these came close:
! 144: 4 8 15 26 3 22 24
! 145: 10 8 15 26 3 22 24
! 146: 11 8 15 26 3 22 24
! 147: -------------------------------------------------------------------------------
! 148: */
! 149: #define final(a,b,c) \
! 150: { \
! 151: c ^= b; c -= rot(b,14); \
! 152: a ^= c; a -= rot(c,11); \
! 153: b ^= a; b -= rot(a,25); \
! 154: c ^= b; c -= rot(b,16); \
! 155: a ^= c; a -= rot(c,4); \
! 156: b ^= a; b -= rot(a,14); \
! 157: c ^= b; c -= rot(b,24); \
! 158: }
! 159:
! 160: /*
! 161: --------------------------------------------------------------------
! 162: This works on all machines. To be useful, it requires
! 163: -- that the key be an array of uint32_t's, and
! 164: -- that the length be the number of uint32_t's in the key
! 165:
! 166: The function hashword() is identical to hashlittle() on little-endian
! 167: machines, and identical to hashbig() on big-endian machines,
! 168: except that the length has to be measured in uint32_ts rather than in
! 169: bytes. hashlittle() is more complicated than hashword() only because
! 170: hashlittle() has to dance around fitting the key bytes into registers.
! 171: --------------------------------------------------------------------
! 172: */
! 173: uint32_t hashword(
! 174: const uint32_t *k, /* the key, an array of uint32_t values */
! 175: size_t length, /* the length of the key, in uint32_ts */
! 176: uint32_t initval) /* the previous hash, or an arbitrary value */
! 177: {
! 178: uint32_t a,b,c;
! 179:
! 180: /* Set up the internal state */
! 181: a = b = c = 0xdeadbeef + (((uint32_t)length)<<2) + initval;
! 182:
! 183: /*------------------------------------------------- handle most of the key */
! 184: while (length > 3)
! 185: {
! 186: a += k[0];
! 187: b += k[1];
! 188: c += k[2];
! 189: mix(a,b,c);
! 190: length -= 3;
! 191: k += 3;
! 192: }
! 193:
! 194: /*------------------------------------------- handle the last 3 uint32_t's */
! 195: switch(length) /* all the case statements fall through */
! 196: {
! 197: case 3 : c+=k[2];
! 198: case 2 : b+=k[1];
! 199: case 1 : a+=k[0];
! 200: final(a,b,c);
! 201: case 0: /* case 0: nothing left to add */
! 202: break;
! 203: }
! 204: /*------------------------------------------------------ report the result */
! 205: return c;
! 206: }
! 207:
! 208:
! 209: /*
! 210: --------------------------------------------------------------------
! 211: hashword2() -- same as hashword(), but take two seeds and return two
! 212: 32-bit values. pc and pb must both be nonnull, and *pc and *pb must
! 213: both be initialized with seeds. If you pass in (*pb)==0, the output
! 214: (*pc) will be the same as the return value from hashword().
! 215: --------------------------------------------------------------------
! 216: */
! 217: void hashword2 (
! 218: const uint32_t *k, /* the key, an array of uint32_t values */
! 219: size_t length, /* the length of the key, in uint32_ts */
! 220: uint32_t *pc, /* IN: seed OUT: primary hash value */
! 221: uint32_t *pb) /* IN: more seed OUT: secondary hash value */
! 222: {
! 223: uint32_t a,b,c;
! 224:
! 225: /* Set up the internal state */
! 226: a = b = c = 0xdeadbeef + ((uint32_t)(length<<2)) + *pc;
! 227: c += *pb;
! 228:
! 229: /*------------------------------------------------- handle most of the key */
! 230: while (length > 3)
! 231: {
! 232: a += k[0];
! 233: b += k[1];
! 234: c += k[2];
! 235: mix(a,b,c);
! 236: length -= 3;
! 237: k += 3;
! 238: }
! 239:
! 240: /*------------------------------------------- handle the last 3 uint32_t's */
! 241: switch(length) /* all the case statements fall through */
! 242: {
! 243: case 3 : c+=k[2];
! 244: case 2 : b+=k[1];
! 245: case 1 : a+=k[0];
! 246: final(a,b,c);
! 247: case 0: /* case 0: nothing left to add */
! 248: break;
! 249: }
! 250: /*------------------------------------------------------ report the result */
! 251: *pc=c; *pb=b;
! 252: }
! 253:
! 254:
! 255: /*
! 256: -------------------------------------------------------------------------------
! 257: hashlittle() -- hash a variable-length key into a 32-bit value
! 258: k : the key (the unaligned variable-length array of bytes)
! 259: length : the length of the key, counting by bytes
! 260: initval : can be any 4-byte value
! 261: Returns a 32-bit value. Every bit of the key affects every bit of
! 262: the return value. Two keys differing by one or two bits will have
! 263: totally different hash values.
! 264:
! 265: The best hash table sizes are powers of 2. There is no need to do
! 266: mod a prime (mod is sooo slow!). If you need less than 32 bits,
! 267: use a bitmask. For example, if you need only 10 bits, do
! 268: h = (h & hashmask(10));
! 269: In which case, the hash table should have hashsize(10) elements.
! 270:
! 271: If you are hashing n strings (uint8_t **)k, do it like this:
! 272: for (i=0, h=0; i<n; ++i) h = hashlittle( k[i], len[i], h);
! 273:
! 274: By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this
! 275: code any way you wish, private, educational, or commercial. It's free.
! 276:
! 277: Use for hash table lookup, or anything where one collision in 2^^32 is
! 278: acceptable. Do NOT use for cryptographic purposes.
! 279: -------------------------------------------------------------------------------
! 280: */
! 281:
! 282: uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
! 283: {
! 284: uint32_t a,b,c; /* internal state */
! 285: union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */
! 286:
! 287: /* Set up the internal state */
! 288: a = b = c = 0xdeadbeef + ((uint32_t)length) + initval;
! 289:
! 290: u.ptr = key;
! 291: if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
! 292: const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
! 293: /*const uint8_t *k8;*/
! 294:
! 295: /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
! 296: while (length > 12)
! 297: {
! 298: a += k[0];
! 299: b += k[1];
! 300: c += k[2];
! 301: mix(a,b,c);
! 302: length -= 12;
! 303: k += 3;
! 304: }
! 305:
! 306: /*----------------------------- handle the last (probably partial) block */
! 307: /*
! 308: * "k[2]&0xffffff" actually reads beyond the end of the string, but
! 309: * then masks off the part it's not allowed to read. Because the
! 310: * string is aligned, the masked-off tail is in the same word as the
! 311: * rest of the string. Every machine with memory protection I've seen
! 312: * does it on word boundaries, so is OK with this. But VALGRIND will
! 313: * still catch it and complain. The masking trick does make the hash
! 314: * noticably faster for short strings (like English words).
! 315: */
! 316: #ifndef VALGRIND
! 317:
! 318: switch(length)
! 319: {
! 320: case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
! 321: case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
! 322: case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
! 323: case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
! 324: case 8 : b+=k[1]; a+=k[0]; break;
! 325: case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
! 326: case 6 : b+=k[1]&0xffff; a+=k[0]; break;
! 327: case 5 : b+=k[1]&0xff; a+=k[0]; break;
! 328: case 4 : a+=k[0]; break;
! 329: case 3 : a+=k[0]&0xffffff; break;
! 330: case 2 : a+=k[0]&0xffff; break;
! 331: case 1 : a+=k[0]&0xff; break;
! 332: case 0 : return c; /* zero length strings require no mixing */
! 333: }
! 334:
! 335: #else /* make valgrind happy */
! 336:
! 337: k8 = (const uint8_t *)k;
! 338: switch(length)
! 339: {
! 340: case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
! 341: case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
! 342: case 10: c+=((uint32_t)k8[9])<<8; /* fall through */
! 343: case 9 : c+=k8[8]; /* fall through */
! 344: case 8 : b+=k[1]; a+=k[0]; break;
! 345: case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
! 346: case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */
! 347: case 5 : b+=k8[4]; /* fall through */
! 348: case 4 : a+=k[0]; break;
! 349: case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
! 350: case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */
! 351: case 1 : a+=k8[0]; break;
! 352: case 0 : return c;
! 353: }
! 354:
! 355: #endif /* !valgrind */
! 356:
! 357: } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
! 358: const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
! 359: const uint8_t *k8;
! 360:
! 361: /*--------------- all but last block: aligned reads and different mixing */
! 362: while (length > 12)
! 363: {
! 364: a += k[0] + (((uint32_t)k[1])<<16);
! 365: b += k[2] + (((uint32_t)k[3])<<16);
! 366: c += k[4] + (((uint32_t)k[5])<<16);
! 367: mix(a,b,c);
! 368: length -= 12;
! 369: k += 6;
! 370: }
! 371:
! 372: /*----------------------------- handle the last (probably partial) block */
! 373: k8 = (const uint8_t *)k;
! 374: switch(length)
! 375: {
! 376: case 12: c+=k[4]+(((uint32_t)k[5])<<16);
! 377: b+=k[2]+(((uint32_t)k[3])<<16);
! 378: a+=k[0]+(((uint32_t)k[1])<<16);
! 379: break;
! 380: case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
! 381: case 10: c+=k[4];
! 382: b+=k[2]+(((uint32_t)k[3])<<16);
! 383: a+=k[0]+(((uint32_t)k[1])<<16);
! 384: break;
! 385: case 9 : c+=k8[8]; /* fall through */
! 386: case 8 : b+=k[2]+(((uint32_t)k[3])<<16);
! 387: a+=k[0]+(((uint32_t)k[1])<<16);
! 388: break;
! 389: case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
! 390: case 6 : b+=k[2];
! 391: a+=k[0]+(((uint32_t)k[1])<<16);
! 392: break;
! 393: case 5 : b+=k8[4]; /* fall through */
! 394: case 4 : a+=k[0]+(((uint32_t)k[1])<<16);
! 395: break;
! 396: case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
! 397: case 2 : a+=k[0];
! 398: break;
! 399: case 1 : a+=k8[0];
! 400: break;
! 401: case 0 : return c; /* zero length requires no mixing */
! 402: }
! 403:
! 404: } else { /* need to read the key one byte at a time */
! 405: const uint8_t *k = (const uint8_t *)key;
! 406:
! 407: /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
! 408: while (length > 12)
! 409: {
! 410: a += k[0];
! 411: a += ((uint32_t)k[1])<<8;
! 412: a += ((uint32_t)k[2])<<16;
! 413: a += ((uint32_t)k[3])<<24;
! 414: b += k[4];
! 415: b += ((uint32_t)k[5])<<8;
! 416: b += ((uint32_t)k[6])<<16;
! 417: b += ((uint32_t)k[7])<<24;
! 418: c += k[8];
! 419: c += ((uint32_t)k[9])<<8;
! 420: c += ((uint32_t)k[10])<<16;
! 421: c += ((uint32_t)k[11])<<24;
! 422: mix(a,b,c);
! 423: length -= 12;
! 424: k += 12;
! 425: }
! 426:
! 427: /*-------------------------------- last block: affect all 32 bits of (c) */
! 428: switch(length) /* all the case statements fall through */
! 429: {
! 430: case 12: c+=((uint32_t)k[11])<<24;
! 431: case 11: c+=((uint32_t)k[10])<<16;
! 432: case 10: c+=((uint32_t)k[9])<<8;
! 433: case 9 : c+=k[8];
! 434: case 8 : b+=((uint32_t)k[7])<<24;
! 435: case 7 : b+=((uint32_t)k[6])<<16;
! 436: case 6 : b+=((uint32_t)k[5])<<8;
! 437: case 5 : b+=k[4];
! 438: case 4 : a+=((uint32_t)k[3])<<24;
! 439: case 3 : a+=((uint32_t)k[2])<<16;
! 440: case 2 : a+=((uint32_t)k[1])<<8;
! 441: case 1 : a+=k[0];
! 442: break;
! 443: case 0 : return c;
! 444: }
! 445: }
! 446:
! 447: final(a,b,c);
! 448: return c;
! 449: }
! 450:
! 451:
! 452: /*
! 453: * hashlittle2: return 2 32-bit hash values
! 454: *
! 455: * This is identical to hashlittle(), except it returns two 32-bit hash
! 456: * values instead of just one. This is good enough for hash table
! 457: * lookup with 2^^64 buckets, or if you want a second hash if you're not
! 458: * happy with the first, or if you want a probably-unique 64-bit ID for
! 459: * the key. *pc is better mixed than *pb, so use *pc first. If you want
! 460: * a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
! 461: */
! 462: void hashlittle2(
! 463: const void *key, /* the key to hash */
! 464: size_t length, /* length of the key */
! 465: uint32_t *pc, /* IN: primary initval, OUT: primary hash */
! 466: uint32_t *pb) /* IN: secondary initval, OUT: secondary hash */
! 467: {
! 468: uint32_t a,b,c; /* internal state */
! 469: union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */
! 470:
! 471: /* Set up the internal state */
! 472: a = b = c = 0xdeadbeef + ((uint32_t)length) + *pc;
! 473: c += *pb;
! 474:
! 475: u.ptr = key;
! 476: if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
! 477: const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
! 478: /*const uint8_t *k8;*/
! 479:
! 480: /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
! 481: while (length > 12)
! 482: {
! 483: a += k[0];
! 484: b += k[1];
! 485: c += k[2];
! 486: mix(a,b,c);
! 487: length -= 12;
! 488: k += 3;
! 489: }
! 490:
! 491: /*----------------------------- handle the last (probably partial) block */
! 492: /*
! 493: * "k[2]&0xffffff" actually reads beyond the end of the string, but
! 494: * then masks off the part it's not allowed to read. Because the
! 495: * string is aligned, the masked-off tail is in the same word as the
! 496: * rest of the string. Every machine with memory protection I've seen
! 497: * does it on word boundaries, so is OK with this. But VALGRIND will
! 498: * still catch it and complain. The masking trick does make the hash
! 499: * noticably faster for short strings (like English words).
! 500: */
! 501: #ifndef VALGRIND
! 502:
! 503: switch(length)
! 504: {
! 505: case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
! 506: case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
! 507: case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
! 508: case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
! 509: case 8 : b+=k[1]; a+=k[0]; break;
! 510: case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
! 511: case 6 : b+=k[1]&0xffff; a+=k[0]; break;
! 512: case 5 : b+=k[1]&0xff; a+=k[0]; break;
! 513: case 4 : a+=k[0]; break;
! 514: case 3 : a+=k[0]&0xffffff; break;
! 515: case 2 : a+=k[0]&0xffff; break;
! 516: case 1 : a+=k[0]&0xff; break;
! 517: case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
! 518: }
! 519:
! 520: #else /* make valgrind happy */
! 521:
! 522: k8 = (const uint8_t *)k;
! 523: switch(length)
! 524: {
! 525: case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
! 526: case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
! 527: case 10: c+=((uint32_t)k8[9])<<8; /* fall through */
! 528: case 9 : c+=k8[8]; /* fall through */
! 529: case 8 : b+=k[1]; a+=k[0]; break;
! 530: case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
! 531: case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */
! 532: case 5 : b+=k8[4]; /* fall through */
! 533: case 4 : a+=k[0]; break;
! 534: case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
! 535: case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */
! 536: case 1 : a+=k8[0]; break;
! 537: case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
! 538: }
! 539:
! 540: #endif /* !valgrind */
! 541:
! 542: } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
! 543: const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
! 544: const uint8_t *k8;
! 545:
! 546: /*--------------- all but last block: aligned reads and different mixing */
! 547: while (length > 12)
! 548: {
! 549: a += k[0] + (((uint32_t)k[1])<<16);
! 550: b += k[2] + (((uint32_t)k[3])<<16);
! 551: c += k[4] + (((uint32_t)k[5])<<16);
! 552: mix(a,b,c);
! 553: length -= 12;
! 554: k += 6;
! 555: }
! 556:
! 557: /*----------------------------- handle the last (probably partial) block */
! 558: k8 = (const uint8_t *)k;
! 559: switch(length)
! 560: {
! 561: case 12: c+=k[4]+(((uint32_t)k[5])<<16);
! 562: b+=k[2]+(((uint32_t)k[3])<<16);
! 563: a+=k[0]+(((uint32_t)k[1])<<16);
! 564: break;
! 565: case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
! 566: case 10: c+=k[4];
! 567: b+=k[2]+(((uint32_t)k[3])<<16);
! 568: a+=k[0]+(((uint32_t)k[1])<<16);
! 569: break;
! 570: case 9 : c+=k8[8]; /* fall through */
! 571: case 8 : b+=k[2]+(((uint32_t)k[3])<<16);
! 572: a+=k[0]+(((uint32_t)k[1])<<16);
! 573: break;
! 574: case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
! 575: case 6 : b+=k[2];
! 576: a+=k[0]+(((uint32_t)k[1])<<16);
! 577: break;
! 578: case 5 : b+=k8[4]; /* fall through */
! 579: case 4 : a+=k[0]+(((uint32_t)k[1])<<16);
! 580: break;
! 581: case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
! 582: case 2 : a+=k[0];
! 583: break;
! 584: case 1 : a+=k8[0];
! 585: break;
! 586: case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
! 587: }
! 588:
! 589: } else { /* need to read the key one byte at a time */
! 590: const uint8_t *k = (const uint8_t *)key;
! 591:
! 592: /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
! 593: while (length > 12)
! 594: {
! 595: a += k[0];
! 596: a += ((uint32_t)k[1])<<8;
! 597: a += ((uint32_t)k[2])<<16;
! 598: a += ((uint32_t)k[3])<<24;
! 599: b += k[4];
! 600: b += ((uint32_t)k[5])<<8;
! 601: b += ((uint32_t)k[6])<<16;
! 602: b += ((uint32_t)k[7])<<24;
! 603: c += k[8];
! 604: c += ((uint32_t)k[9])<<8;
! 605: c += ((uint32_t)k[10])<<16;
! 606: c += ((uint32_t)k[11])<<24;
! 607: mix(a,b,c);
! 608: length -= 12;
! 609: k += 12;
! 610: }
! 611:
! 612: /*-------------------------------- last block: affect all 32 bits of (c) */
! 613: switch(length) /* all the case statements fall through */
! 614: {
! 615: case 12: c+=((uint32_t)k[11])<<24;
! 616: case 11: c+=((uint32_t)k[10])<<16;
! 617: case 10: c+=((uint32_t)k[9])<<8;
! 618: case 9 : c+=k[8];
! 619: case 8 : b+=((uint32_t)k[7])<<24;
! 620: case 7 : b+=((uint32_t)k[6])<<16;
! 621: case 6 : b+=((uint32_t)k[5])<<8;
! 622: case 5 : b+=k[4];
! 623: case 4 : a+=((uint32_t)k[3])<<24;
! 624: case 3 : a+=((uint32_t)k[2])<<16;
! 625: case 2 : a+=((uint32_t)k[1])<<8;
! 626: case 1 : a+=k[0];
! 627: break;
! 628: case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
! 629: }
! 630: }
! 631:
! 632: final(a,b,c);
! 633: *pc=c; *pb=b;
! 634: }
! 635:
! 636:
! 637:
! 638: /*
! 639: * hashbig():
! 640: * This is the same as hashword() on big-endian machines. It is different
! 641: * from hashlittle() on all machines. hashbig() takes advantage of
! 642: * big-endian byte ordering.
! 643: */
! 644: uint32_t hashbig( const void *key, size_t length, uint32_t initval)
! 645: {
! 646: uint32_t a,b,c;
! 647: union { const void *ptr; size_t i; } u; /* to cast key to (size_t) happily */
! 648:
! 649: /* Set up the internal state */
! 650: a = b = c = 0xdeadbeef + ((uint32_t)length) + initval;
! 651:
! 652: u.ptr = key;
! 653: if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
! 654: const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
! 655: /*const uint8_t *k8;*/
! 656:
! 657: /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
! 658: while (length > 12)
! 659: {
! 660: a += k[0];
! 661: b += k[1];
! 662: c += k[2];
! 663: mix(a,b,c);
! 664: length -= 12;
! 665: k += 3;
! 666: }
! 667:
! 668: /*----------------------------- handle the last (probably partial) block */
! 669: /*
! 670: * "k[2]<<8" actually reads beyond the end of the string, but
! 671: * then shifts out the part it's not allowed to read. Because the
! 672: * string is aligned, the illegal read is in the same word as the
! 673: * rest of the string. Every machine with memory protection I've seen
! 674: * does it on word boundaries, so is OK with this. But VALGRIND will
! 675: * still catch it and complain. The masking trick does make the hash
! 676: * noticably faster for short strings (like English words).
! 677: */
! 678: #ifndef VALGRIND
! 679:
! 680: switch(length)
! 681: {
! 682: case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
! 683: case 11: c+=k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
! 684: case 10: c+=k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
! 685: case 9 : c+=k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
! 686: case 8 : b+=k[1]; a+=k[0]; break;
! 687: case 7 : b+=k[1]&0xffffff00; a+=k[0]; break;
! 688: case 6 : b+=k[1]&0xffff0000; a+=k[0]; break;
! 689: case 5 : b+=k[1]&0xff000000; a+=k[0]; break;
! 690: case 4 : a+=k[0]; break;
! 691: case 3 : a+=k[0]&0xffffff00; break;
! 692: case 2 : a+=k[0]&0xffff0000; break;
! 693: case 1 : a+=k[0]&0xff000000; break;
! 694: case 0 : return c; /* zero length strings require no mixing */
! 695: }
! 696:
! 697: #else /* make valgrind happy */
! 698:
! 699: k8 = (const uint8_t *)k;
! 700: switch(length) /* all the case statements fall through */
! 701: {
! 702: case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
! 703: case 11: c+=((uint32_t)k8[10])<<8; /* fall through */
! 704: case 10: c+=((uint32_t)k8[9])<<16; /* fall through */
! 705: case 9 : c+=((uint32_t)k8[8])<<24; /* fall through */
! 706: case 8 : b+=k[1]; a+=k[0]; break;
! 707: case 7 : b+=((uint32_t)k8[6])<<8; /* fall through */
! 708: case 6 : b+=((uint32_t)k8[5])<<16; /* fall through */
! 709: case 5 : b+=((uint32_t)k8[4])<<24; /* fall through */
! 710: case 4 : a+=k[0]; break;
! 711: case 3 : a+=((uint32_t)k8[2])<<8; /* fall through */
! 712: case 2 : a+=((uint32_t)k8[1])<<16; /* fall through */
! 713: case 1 : a+=((uint32_t)k8[0])<<24; break;
! 714: case 0 : return c;
! 715: }
! 716:
! 717: #endif /* !VALGRIND */
! 718:
! 719: } else { /* need to read the key one byte at a time */
! 720: const uint8_t *k = (const uint8_t *)key;
! 721:
! 722: /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
! 723: while (length > 12)
! 724: {
! 725: a += ((uint32_t)k[0])<<24;
! 726: a += ((uint32_t)k[1])<<16;
! 727: a += ((uint32_t)k[2])<<8;
! 728: a += ((uint32_t)k[3]);
! 729: b += ((uint32_t)k[4])<<24;
! 730: b += ((uint32_t)k[5])<<16;
! 731: b += ((uint32_t)k[6])<<8;
! 732: b += ((uint32_t)k[7]);
! 733: c += ((uint32_t)k[8])<<24;
! 734: c += ((uint32_t)k[9])<<16;
! 735: c += ((uint32_t)k[10])<<8;
! 736: c += ((uint32_t)k[11]);
! 737: mix(a,b,c);
! 738: length -= 12;
! 739: k += 12;
! 740: }
! 741:
! 742: /*-------------------------------- last block: affect all 32 bits of (c) */
! 743: switch(length) /* all the case statements fall through */
! 744: {
! 745: case 12: c+=k[11];
! 746: case 11: c+=((uint32_t)k[10])<<8;
! 747: case 10: c+=((uint32_t)k[9])<<16;
! 748: case 9 : c+=((uint32_t)k[8])<<24;
! 749: case 8 : b+=k[7];
! 750: case 7 : b+=((uint32_t)k[6])<<8;
! 751: case 6 : b+=((uint32_t)k[5])<<16;
! 752: case 5 : b+=((uint32_t)k[4])<<24;
! 753: case 4 : a+=k[3];
! 754: case 3 : a+=((uint32_t)k[2])<<8;
! 755: case 2 : a+=((uint32_t)k[1])<<16;
! 756: case 1 : a+=((uint32_t)k[0])<<24;
! 757: break;
! 758: case 0 : return c;
! 759: }
! 760: }
! 761:
! 762: final(a,b,c);
! 763: return c;
! 764: }
! 765:
! 766:
! 767: #ifdef SELF_TEST
! 768:
! 769: /* used for timings */
! 770: void driver1()
! 771: {
! 772: uint8_t buf[256];
! 773: uint32_t i;
! 774: uint32_t h=0;
! 775: time_t a,z;
! 776:
! 777: time(&a);
! 778: for (i=0; i<256; ++i) buf[i] = 'x';
! 779: for (i=0; i<1; ++i)
! 780: {
! 781: h = hashlittle(&buf[0],1,h);
! 782: }
! 783: time(&z);
! 784: if (z-a > 0) printf("time %d %.8x\n", z-a, h);
! 785: }
! 786:
! 787: /* check that every input bit changes every output bit half the time */
! 788: #define HASHSTATE 1
! 789: #define HASHLEN 1
! 790: #define MAXPAIR 60
! 791: #define MAXLEN 70
! 792: void driver2()
! 793: {
! 794: uint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1];
! 795: uint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z;
! 796: uint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE];
! 797: uint32_t x[HASHSTATE],y[HASHSTATE];
! 798: uint32_t hlen;
! 799:
! 800: printf("No more than %d trials should ever be needed \n",MAXPAIR/2);
! 801: for (hlen=0; hlen < MAXLEN; ++hlen)
! 802: {
! 803: z=0;
! 804: for (i=0; i<hlen; ++i) /*----------------------- for each input byte, */
! 805: {
! 806: for (j=0; j<8; ++j) /*------------------------ for each input bit, */
! 807: {
! 808: for (m=1; m<8; ++m) /*------------ for serveral possible initvals, */
! 809: {
! 810: for (l=0; l<HASHSTATE; ++l)
! 811: e[l]=f[l]=g[l]=h[l]=x[l]=y[l]=~((uint32_t)0);
! 812:
! 813: /*---- check that every output bit is affected by that input bit */
! 814: for (k=0; k<MAXPAIR; k+=2)
! 815: {
! 816: uint32_t finished=1;
! 817: /* keys have one bit different */
! 818: for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (uint8_t)0;}
! 819: /* have a and b be two keys differing in only one bit */
! 820: a[i] ^= (k<<j);
! 821: a[i] ^= (k>>(8-j));
! 822: c[0] = hashlittle(a, hlen, m);
! 823: b[i] ^= ((k+1)<<j);
! 824: b[i] ^= ((k+1)>>(8-j));
! 825: d[0] = hashlittle(b, hlen, m);
! 826: /* check every bit is 1, 0, set, and not set at least once */
! 827: for (l=0; l<HASHSTATE; ++l)
! 828: {
! 829: e[l] &= (c[l]^d[l]);
! 830: f[l] &= ~(c[l]^d[l]);
! 831: g[l] &= c[l];
! 832: h[l] &= ~c[l];
! 833: x[l] &= d[l];
! 834: y[l] &= ~d[l];
! 835: if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0;
! 836: }
! 837: if (finished) break;
! 838: }
! 839: if (k>z) z=k;
! 840: if (k==MAXPAIR)
! 841: {
! 842: printf("Some bit didn't change: ");
! 843: printf("%.8x %.8x %.8x %.8x %.8x %.8x ",
! 844: e[0],f[0],g[0],h[0],x[0],y[0]);
! 845: printf("i %d j %d m %d len %d\n", i, j, m, hlen);
! 846: }
! 847: if (z==MAXPAIR) goto done;
! 848: }
! 849: }
! 850: }
! 851: done:
! 852: if (z < MAXPAIR)
! 853: {
! 854: printf("Mix success %2d bytes %2d initvals ",i,m);
! 855: printf("required %d trials\n", z/2);
! 856: }
! 857: }
! 858: printf("\n");
! 859: }
! 860:
! 861: /* Check for reading beyond the end of the buffer and alignment problems */
! 862: void driver3()
! 863: {
! 864: uint8_t buf[MAXLEN+20], *b;
! 865: uint32_t len;
! 866: uint8_t q[] = "This is the time for all good men to come to the aid of their country...";
! 867: uint32_t h;
! 868: uint8_t qq[] = "xThis is the time for all good men to come to the aid of their country...";
! 869: uint32_t i;
! 870: uint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country...";
! 871: uint32_t j;
! 872: uint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country...";
! 873: uint32_t ref,x,y;
! 874: uint8_t *p;
! 875:
! 876: printf("Endianness. These lines should all be the same (for values filled in):\n");
! 877: printf("%.8x %.8x %.8x\n",
! 878: hashword((const uint32_t *)q, (sizeof(q)-1)/4, 13),
! 879: hashword((const uint32_t *)q, (sizeof(q)-5)/4, 13),
! 880: hashword((const uint32_t *)q, (sizeof(q)-9)/4, 13));
! 881: p = q;
! 882: printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
! 883: hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
! 884: hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
! 885: hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
! 886: hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
! 887: hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
! 888: hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
! 889: p = &qq[1];
! 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 = &qqq[2];
! 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 = &qqqq[3];
! 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: printf("\n");
! 914:
! 915: /* check that hashlittle2 and hashlittle produce the same results */
! 916: i=47; j=0;
! 917: hashlittle2(q, sizeof(q), &i, &j);
! 918: if (hashlittle(q, sizeof(q), 47) != i)
! 919: printf("hashlittle2 and hashlittle mismatch\n");
! 920:
! 921: /* check that hashword2 and hashword produce the same results */
! 922: len = 0xdeadbeef;
! 923: i=47, j=0;
! 924: hashword2(&len, 1, &i, &j);
! 925: if (hashword(&len, 1, 47) != i)
! 926: printf("hashword2 and hashword mismatch %x %x\n",
! 927: i, hashword(&len, 1, 47));
! 928:
! 929: /* check hashlittle doesn't read before or after the ends of the string */
! 930: for (h=0, b=buf+1; h<8; ++h, ++b)
! 931: {
! 932: for (i=0; i<MAXLEN; ++i)
! 933: {
! 934: len = i;
! 935: for (j=0; j<i; ++j) *(b+j)=0;
! 936:
! 937: /* these should all be equal */
! 938: ref = hashlittle(b, len, (uint32_t)1);
! 939: *(b+i)=(uint8_t)~0;
! 940: *(b-1)=(uint8_t)~0;
! 941: x = hashlittle(b, len, (uint32_t)1);
! 942: y = hashlittle(b, len, (uint32_t)1);
! 943: if ((ref != x) || (ref != y))
! 944: {
! 945: printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y,
! 946: h, i);
! 947: }
! 948: }
! 949: }
! 950: }
! 951:
! 952: /* check for problems with nulls */
! 953: void driver4()
! 954: {
! 955: uint8_t buf[1];
! 956: uint32_t h,i,state[HASHSTATE];
! 957:
! 958:
! 959: buf[0] = ~0;
! 960: for (i=0; i<HASHSTATE; ++i) state[i] = 1;
! 961: printf("These should all be different\n");
! 962: for (i=0, h=0; i<8; ++i)
! 963: {
! 964: h = hashlittle(buf, 0, h);
! 965: printf("%2ld 0-byte strings, hash is %.8x\n", i, h);
! 966: }
! 967: }
! 968:
! 969:
! 970: int main()
! 971: {
! 972: driver1(); /* test that the key is hashed: used for timings */
! 973: driver2(); /* test that whole key is hashed thoroughly */
! 974: driver3(); /* test that nothing but the key is hashed */
! 975: driver4(); /* test hashing multiple buffers (all buffers are null) */
! 976: return 1;
! 977: }
! 978:
! 979: #endif /* SELF_TEST */
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