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rpmio/lookup3.c

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00001 /* -------------------------------------------------------------------- */
00002 /*
00003  * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
00004  * 
00005  * These are functions for producing 32-bit hashes for hash table lookup.
00006  * jlu32w(), jlu32l(), jlu32lpair(), jlu32b(), _JLU3_MIX(), and _JLU3_FINAL() 
00007  * are externally useful functions.  Routines to test the hash are included 
00008  * if SELF_TEST is defined.  You can use this free for any purpose.  It's in
00009  * the public domain.  It has no warranty.
00010  * 
00011  * You probably want to use jlu32l().  jlu32l() and jlu32b()
00012  * hash byte arrays.  jlu32l() is is faster than jlu32b() on
00013  * little-endian machines.  Intel and AMD are little-endian machines.
00014  * On second thought, you probably want jlu32lpair(), which is identical to
00015  * jlu32l() except it returns two 32-bit hashes for the price of one.  
00016  * You could implement jlu32bpair() if you wanted but I haven't bothered here.
00017  * 
00018  * If you want to find a hash of, say, exactly 7 integers, do
00019  *   a = i1;  b = i2;  c = i3;
00020  *   _JLU3_MIX(a,b,c);
00021  *   a += i4; b += i5; c += i6;
00022  *   _JLU3_MIX(a,b,c);
00023  *   a += i7;
00024  *   _JLU3_FINAL(a,b,c);
00025  * then use c as the hash value.  If you have a variable size array of
00026  * 4-byte integers to hash, use jlu32w().  If you have a byte array (like
00027  * a character string), use jlu32l().  If you have several byte arrays, or
00028  * a mix of things, see the comments above jlu32l().  
00029  * 
00030  * Why is this so big?  I read 12 bytes at a time into 3 4-byte integers, 
00031  * then mix those integers.  This is fast (you can do a lot more thorough
00032  * mixing with 12*3 instructions on 3 integers than you can with 3 instructions
00033  * on 1 byte), but shoehorning those bytes into integers efficiently is messy.
00034 */
00035 /* -------------------------------------------------------------------- */
00036 
00037 #include "system.h"
00038 #include "rpmiotypes.h"
00039 #include "debug.h"
00040 
00041 #if defined(_JLU3_SELFTEST)
00042 # define _JLU3_jlu32w           1
00043 # define _JLU3_jlu32l           1
00044 # define _JLU3_jlu32lpair       1
00045 # define _JLU3_jlu32b           1
00046 #endif
00047 
00048 /*@-redef@*/
00049 /*@unchecked@*/
00050 static const union _dbswap {
00051     const rpmuint32_t ui;
00052     const unsigned char uc[4];
00053 } endian = { .ui = 0x11223344 };
00054 # define HASH_LITTLE_ENDIAN     (endian.uc[0] == (unsigned char) 0x44)
00055 # define HASH_BIG_ENDIAN        (endian.uc[0] == (unsigned char) 0x11)
00056 /*@=redef@*/
00057 
00058 #ifndef ROTL32
00059 # define ROTL32(x, s) (((x) << (s)) | ((x) >> (32 - (s))))
00060 #endif
00061 
00062 /* NOTE: The _size parameter should be in bytes. */
00063 #define _JLU3_INIT(_h, _size)   (0xdeadbeef + ((rpmuint32_t)(_size)) + (_h))
00064 
00065 /* -------------------------------------------------------------------- */
00066 /*
00067  * _JLU3_MIX -- mix 3 32-bit values reversibly.
00068  * 
00069  * This is reversible, so any information in (a,b,c) before _JLU3_MIX() is
00070  * still in (a,b,c) after _JLU3_MIX().
00071  * 
00072  * If four pairs of (a,b,c) inputs are run through _JLU3_MIX(), or through
00073  * _JLU3_MIX() in reverse, there are at least 32 bits of the output that
00074  * are sometimes the same for one pair and different for another pair.
00075  * This was tested for:
00076  * * pairs that differed by one bit, by two bits, in any combination
00077  *   of top bits of (a,b,c), or in any combination of bottom bits of
00078  *   (a,b,c).
00079  * * "differ" is defined as +, -, ^, or ~^.  For + and -, I transformed
00080  *   the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
00081  *   is commonly produced by subtraction) look like a single 1-bit
00082  *   difference.
00083  * * the base values were pseudorandom, all zero but one bit set, or 
00084  *   all zero plus a counter that starts at zero.
00085  * 
00086  * Some k values for my "a-=c; a^=ROTL32(c,k); c+=b;" arrangement that
00087  * satisfy this are
00088  *     4  6  8 16 19  4
00089  *     9 15  3 18 27 15
00090  *    14  9  3  7 17  3
00091  * Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
00092  * for "differ" defined as + with a one-bit base and a two-bit delta.  I
00093  * used http://burtleburtle.net/bob/hash/avalanche.html to choose 
00094  * the operations, constants, and arrangements of the variables.
00095  * 
00096  * This does not achieve avalanche.  There are input bits of (a,b,c)
00097  * that fail to affect some output bits of (a,b,c), especially of a.  The
00098  * most thoroughly mixed value is c, but it doesn't really even achieve
00099  * avalanche in c.
00100  * 
00101  * This allows some parallelism.  Read-after-writes are good at doubling
00102  * the number of bits affected, so the goal of mixing pulls in the opposite
00103  * direction as the goal of parallelism.  I did what I could.  Rotates
00104  * seem to cost as much as shifts on every machine I could lay my hands
00105  * on, and rotates are much kinder to the top and bottom bits, so I used
00106  * rotates.
00107  */
00108 /* -------------------------------------------------------------------- */
00109 #define _JLU3_MIX(a,b,c) \
00110 { \
00111   a -= c;  a ^= ROTL32(c, 4);  c += b; \
00112   b -= a;  b ^= ROTL32(a, 6);  a += c; \
00113   c -= b;  c ^= ROTL32(b, 8);  b += a; \
00114   a -= c;  a ^= ROTL32(c,16);  c += b; \
00115   b -= a;  b ^= ROTL32(a,19);  a += c; \
00116   c -= b;  c ^= ROTL32(b, 4);  b += a; \
00117 }
00118 
00119 /* -------------------------------------------------------------------- */
00143 /* -------------------------------------------------------------------- */
00144 #define _JLU3_FINAL(a,b,c) \
00145 { \
00146   c ^= b; c -= ROTL32(b,14); \
00147   a ^= c; a -= ROTL32(c,11); \
00148   b ^= a; b -= ROTL32(a,25); \
00149   c ^= b; c -= ROTL32(b,16); \
00150   a ^= c; a -= ROTL32(c,4);  \
00151   b ^= a; b -= ROTL32(a,14); \
00152   c ^= b; c -= ROTL32(b,24); \
00153 }
00154 
00155 #if defined(_JLU3_jlu32w)
00156 rpmuint32_t jlu32w(rpmuint32_t h, /*@null@*/ const rpmuint32_t *k, size_t size)
00157         /*@*/;
00158 /* -------------------------------------------------------------------- */
00175 /* -------------------------------------------------------------------- */
00176 rpmuint32_t jlu32w(rpmuint32_t h, const rpmuint32_t *k, size_t size)
00177 {
00178     rpmuint32_t a = _JLU3_INIT(h, (size * sizeof(*k)));
00179     rpmuint32_t b = a;
00180     rpmuint32_t c = a;
00181 
00182     if (k == NULL)
00183         goto exit;
00184 
00185     /*----------------------------------------------- handle most of the key */
00186     while (size > 3) {
00187         a += k[0];
00188         b += k[1];
00189         c += k[2];
00190         _JLU3_MIX(a,b,c);
00191         size -= 3;
00192         k += 3;
00193     }
00194 
00195     /*----------------------------------------- handle the last 3 rpmuint32_t's */
00196     switch (size) {
00197     case 3 : c+=k[2];
00198     case 2 : b+=k[1];
00199     case 1 : a+=k[0];
00200         _JLU3_FINAL(a,b,c);
00201         /*@fallthrough@*/
00202     case 0:
00203         break;
00204     }
00205     /*---------------------------------------------------- report the result */
00206 exit:
00207     return c;
00208 }
00209 #endif  /* defined(_JLU3_jlu32w) */
00210 
00211 #if defined(_JLU3_jlu32l)
00212 rpmuint32_t jlu32l(rpmuint32_t h, const void *key, size_t size)
00213         /*@*/;
00214 /* -------------------------------------------------------------------- */
00215 /*
00216  * jlu32l() -- hash a variable-length key into a 32-bit value
00217  *   h       : can be any 4-byte value
00218  *   k       : the key (the unaligned variable-length array of bytes)
00219  *   size    : the size of the key, counting by bytes
00220  * Returns a 32-bit value.  Every bit of the key affects every bit of
00221  * the return value.  Two keys differing by one or two bits will have
00222  * totally different hash values.
00223  * 
00224  * The best hash table sizes are powers of 2.  There is no need to do
00225  * mod a prime (mod is sooo slow!).  If you need less than 32 bits,
00226  * use a bitmask.  For example, if you need only 10 bits, do
00227  *   h = (h & hashmask(10));
00228  * In which case, the hash table should have hashsize(10) elements.
00229  * 
00230  * If you are hashing n strings (rpmuint8_t **)k, do it like this:
00231  *   for (i=0, h=0; i<n; ++i) h = jlu32l(h, k[i], len[i]);
00232  * 
00233  * By Bob Jenkins, 2006.  bob_jenkins@burtleburtle.net.  You may use this
00234  * code any way you wish, private, educational, or commercial.  It's free.
00235  * 
00236  * Use for hash table lookup, or anything where one collision in 2^^32 is
00237  * acceptable.  Do NOT use for cryptographic purposes.
00238  *
00239  * @param h             the previous hash, or an arbitrary value
00240  * @param *k            the key, an array of rpmuint8_t values
00241  * @param size          the size of the key
00242  * @return              the lookup3 hash
00243  */
00244 /* -------------------------------------------------------------------- */
00245 rpmuint32_t jlu32l(rpmuint32_t h, const void *key, size_t size)
00246 {
00247     union { const void *ptr; size_t i; } u;
00248     rpmuint32_t a = _JLU3_INIT(h, size);
00249     rpmuint32_t b = a;
00250     rpmuint32_t c = a;
00251 
00252     if (key == NULL)
00253         goto exit;
00254 
00255     u.ptr = key;
00256     if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
00257         const rpmuint32_t *k = (const rpmuint32_t *)key;        /* read 32-bit chunks */
00258 #ifdef  VALGRIND
00259         const rpmuint8_t  *k8;
00260 #endif
00261 
00262     /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
00263         while (size > 12) {
00264             a += k[0];
00265             b += k[1];
00266             c += k[2];
00267             _JLU3_MIX(a,b,c);
00268             size -= 12;
00269             k += 3;
00270         }
00271 
00272         /*------------------------- handle the last (probably partial) block */
00273         /* 
00274          * "k[2]&0xffffff" actually reads beyond the end of the string, but
00275          * then masks off the part it's not allowed to read.  Because the
00276          * string is aligned, the masked-off tail is in the same word as the
00277          * rest of the string.  Every machine with memory protection I've seen
00278          * does it on word boundaries, so is OK with this.  But VALGRIND will
00279          * still catch it and complain.  The masking trick does make the hash
00280          * noticably faster for short strings (like English words).
00281          */
00282 #ifndef VALGRIND
00283 
00284         switch (size) {
00285         case 12:        c += k[2]; b+=k[1]; a+=k[0]; break;
00286         case 11:        c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
00287         case 10:        c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
00288         case  9:        c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
00289         case  8:        b += k[1]; a+=k[0]; break;
00290         case  7:        b += k[1]&0xffffff; a+=k[0]; break;
00291         case  6:        b += k[1]&0xffff; a+=k[0]; break;
00292         case  5:        b += k[1]&0xff; a+=k[0]; break;
00293         case  4:        a += k[0]; break;
00294         case  3:        a += k[0]&0xffffff; break;
00295         case  2:        a += k[0]&0xffff; break;
00296         case  1:        a += k[0]&0xff; break;
00297         case  0:        goto exit;
00298         }
00299 
00300 #else /* make valgrind happy */
00301 
00302         k8 = (const rpmuint8_t *)k;
00303         switch (size) {
00304         case 12:        c += k[2]; b+=k[1]; a+=k[0]     break;
00305         case 11:        c += ((rpmuint32_t)k8[10])<<16; /*@fallthrough@*/
00306         case 10:        c += ((rpmuint32_t)k8[9])<<8;   /*@fallthrough@*/
00307         case  9:        c += k8[8];                     /*@fallthrough@*/
00308         case  8:        b += k[1]; a+=k[0];             break;
00309         case  7:        b += ((rpmuint32_t)k8[6])<<16;  /*@fallthrough@*/
00310         case  6:        b += ((rpmuint32_t)k8[5])<<8;   /*@fallthrough@*/
00311         case  5:        b += k8[4];                     /*@fallthrough@*/
00312         case  4:        a += k[0];                      break;
00313         case  3:        a += ((rpmuint32_t)k8[2])<<16;  /*@fallthrough@*/
00314         case  2:        a += ((rpmuint32_t)k8[1])<<8;   /*@fallthrough@*/
00315         case  1:        a += k8[0];                     break;
00316         case  0:        goto exit;
00317         }
00318 
00319 #endif /* !valgrind */
00320 
00321     } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
00322         const rpmuint16_t *k = (const rpmuint16_t *)key;        /* read 16-bit chunks */
00323         const rpmuint8_t  *k8;
00324 
00325         /*----------- all but last block: aligned reads and different mixing */
00326         while (size > 12) {
00327             a += k[0] + (((rpmuint32_t)k[1])<<16);
00328             b += k[2] + (((rpmuint32_t)k[3])<<16);
00329             c += k[4] + (((rpmuint32_t)k[5])<<16);
00330             _JLU3_MIX(a,b,c);
00331             size -= 12;
00332             k += 6;
00333         }
00334 
00335         /*------------------------- handle the last (probably partial) block */
00336         k8 = (const rpmuint8_t *)k;
00337         switch (size) {
00338         case 12:
00339             c += k[4]+(((rpmuint32_t)k[5])<<16);
00340             b += k[2]+(((rpmuint32_t)k[3])<<16);
00341             a += k[0]+(((rpmuint32_t)k[1])<<16);
00342             break;
00343         case 11:
00344             c += ((rpmuint32_t)k8[10])<<16;
00345             /*@fallthrough@*/
00346         case 10:
00347             c += (rpmuint32_t)k[4];
00348             b += k[2]+(((rpmuint32_t)k[3])<<16);
00349             a += k[0]+(((rpmuint32_t)k[1])<<16);
00350             break;
00351         case  9:
00352             c += (rpmuint32_t)k8[8];
00353             /*@fallthrough@*/
00354         case  8:
00355             b += k[2]+(((rpmuint32_t)k[3])<<16);
00356             a += k[0]+(((rpmuint32_t)k[1])<<16);
00357             break;
00358         case  7:
00359             b += ((rpmuint32_t)k8[6])<<16;
00360             /*@fallthrough@*/
00361         case  6:
00362             b += (rpmuint32_t)k[2];
00363             a += k[0]+(((rpmuint32_t)k[1])<<16);
00364             break;
00365         case  5:
00366             b += (rpmuint32_t)k8[4];
00367             /*@fallthrough@*/
00368         case  4:
00369             a += k[0]+(((rpmuint32_t)k[1])<<16);
00370             break;
00371         case  3:
00372             a += ((rpmuint32_t)k8[2])<<16;
00373             /*@fallthrough@*/
00374         case  2:
00375             a += (rpmuint32_t)k[0];
00376             break;
00377         case  1:
00378             a += (rpmuint32_t)k8[0];
00379             break;
00380         case  0:
00381             goto exit;
00382         }
00383 
00384     } else {            /* need to read the key one byte at a time */
00385         const rpmuint8_t *k = (const rpmuint8_t *)key;
00386 
00387         /*----------- all but the last block: affect some 32 bits of (a,b,c) */
00388         while (size > 12) {
00389             a += (rpmuint32_t)k[0];
00390             a += ((rpmuint32_t)k[1])<<8;
00391             a += ((rpmuint32_t)k[2])<<16;
00392             a += ((rpmuint32_t)k[3])<<24;
00393             b += (rpmuint32_t)k[4];
00394             b += ((rpmuint32_t)k[5])<<8;
00395             b += ((rpmuint32_t)k[6])<<16;
00396             b += ((rpmuint32_t)k[7])<<24;
00397             c += (rpmuint32_t)k[8];
00398             c += ((rpmuint32_t)k[9])<<8;
00399             c += ((rpmuint32_t)k[10])<<16;
00400             c += ((rpmuint32_t)k[11])<<24;
00401             _JLU3_MIX(a,b,c);
00402             size -= 12;
00403             k += 12;
00404         }
00405 
00406         /*---------------------------- last block: affect all 32 bits of (c) */
00407         switch (size) {
00408         case 12:        c += ((rpmuint32_t)k[11])<<24;  /*@fallthrough@*/
00409         case 11:        c += ((rpmuint32_t)k[10])<<16;  /*@fallthrough@*/
00410         case 10:        c += ((rpmuint32_t)k[9])<<8;    /*@fallthrough@*/
00411         case  9:        c += (rpmuint32_t)k[8];         /*@fallthrough@*/
00412         case  8:        b += ((rpmuint32_t)k[7])<<24;   /*@fallthrough@*/
00413         case  7:        b += ((rpmuint32_t)k[6])<<16;   /*@fallthrough@*/
00414         case  6:        b += ((rpmuint32_t)k[5])<<8;    /*@fallthrough@*/
00415         case  5:        b += (rpmuint32_t)k[4];         /*@fallthrough@*/
00416         case  4:        a += ((rpmuint32_t)k[3])<<24;   /*@fallthrough@*/
00417         case  3:        a += ((rpmuint32_t)k[2])<<16;   /*@fallthrough@*/
00418         case  2:        a += ((rpmuint32_t)k[1])<<8;    /*@fallthrough@*/
00419         case  1:        a += (rpmuint32_t)k[0];
00420             break;
00421         case  0:
00422             goto exit;
00423         }
00424     }
00425 
00426     _JLU3_FINAL(a,b,c);
00427 
00428 exit:
00429     return c;
00430 }
00431 #endif  /* defined(_JLU3_jlu32l) */
00432 
00433 #if defined(_JLU3_jlu32lpair)
00434 void jlu32lpair(/*@null@*/ const void *key, size_t size,
00435                 rpmuint32_t *pc, rpmuint32_t *pb)
00436         /*@modifies *pc, *pb@*/;
00453 void jlu32lpair(const void *key, size_t size, rpmuint32_t *pc, rpmuint32_t *pb)
00454 {
00455     union { const void *ptr; size_t i; } u;
00456     rpmuint32_t a = _JLU3_INIT(*pc, size);
00457     rpmuint32_t b = a;
00458     rpmuint32_t c = a;
00459 
00460     if (key == NULL)
00461         goto exit;
00462 
00463     c += *pb;   /* Add the secondary hash. */
00464 
00465     u.ptr = key;
00466     if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
00467         const rpmuint32_t *k = (const rpmuint32_t *)key;        /* read 32-bit chunks */
00468 #ifdef  VALGRIND
00469         const rpmuint8_t  *k8;
00470 #endif
00471 
00472         /*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
00473         while (size > 12) {
00474             a += k[0];
00475             b += k[1];
00476             c += k[2];
00477             _JLU3_MIX(a,b,c);
00478             size -= 12;
00479             k += 3;
00480         }
00481         /*------------------------- handle the last (probably partial) block */
00482         /* 
00483          * "k[2]&0xffffff" actually reads beyond the end of the string, but
00484          * then masks off the part it's not allowed to read.  Because the
00485          * string is aligned, the masked-off tail is in the same word as the
00486          * rest of the string.  Every machine with memory protection I've seen
00487          * does it on word boundaries, so is OK with this.  But VALGRIND will
00488          * still catch it and complain.  The masking trick does make the hash
00489          * noticably faster for short strings (like English words).
00490          */
00491 #ifndef VALGRIND
00492 
00493         switch (size) {
00494         case 12:        c += k[2]; b+=k[1]; a+=k[0]; break;
00495         case 11:        c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
00496         case 10:        c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
00497         case  9:        c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
00498         case  8:        b += k[1]; a+=k[0]; break;
00499         case  7:        b += k[1]&0xffffff; a+=k[0]; break;
00500         case  6:        b += k[1]&0xffff; a+=k[0]; break;
00501         case  5:        b += k[1]&0xff; a+=k[0]; break;
00502         case  4:        a += k[0]; break;
00503         case  3:        a += k[0]&0xffffff; break;
00504         case  2:        a += k[0]&0xffff; break;
00505         case  1:        a += k[0]&0xff; break;
00506         case  0:        goto exit;
00507         }
00508 
00509 #else /* make valgrind happy */
00510 
00511         k8 = (const rpmuint8_t *)k;
00512         switch (size) {
00513         case 12:        c += k[2]; b+=k[1]; a+=k[0];    break;
00514         case 11:        c += ((rpmuint32_t)k8[10])<<16; /*@fallthrough@*/
00515         case 10:        c += ((rpmuint32_t)k8[9])<<8;   /*@fallthrough@*/
00516         case  9:        c += k8[8];                     /*@fallthrough@*/
00517         case  8:        b += k[1]; a+=k[0];             break;
00518         case  7:        b += ((rpmuint32_t)k8[6])<<16;  /*@fallthrough@*/
00519         case  6:        b += ((rpmuint32_t)k8[5])<<8;   /*@fallthrough@*/
00520         case  5:        b += k8[4];                     /*@fallthrough@*/
00521         case  4:        a += k[0];                      break;
00522         case  3:        a += ((rpmuint32_t)k8[2])<<16;  /*@fallthrough@*/
00523         case  2:        a += ((rpmuint32_t)k8[1])<<8;   /*@fallthrough@*/
00524         case  1:        a += k8[0];                     break;
00525         case  0:        goto exit;
00526         }
00527 
00528 #endif /* !valgrind */
00529 
00530     } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
00531         const rpmuint16_t *k = (const rpmuint16_t *)key;        /* read 16-bit chunks */
00532         const rpmuint8_t  *k8;
00533 
00534         /*----------- all but last block: aligned reads and different mixing */
00535         while (size > 12) {
00536             a += k[0] + (((rpmuint32_t)k[1])<<16);
00537             b += k[2] + (((rpmuint32_t)k[3])<<16);
00538             c += k[4] + (((rpmuint32_t)k[5])<<16);
00539             _JLU3_MIX(a,b,c);
00540             size -= 12;
00541             k += 6;
00542         }
00543 
00544         /*------------------------- handle the last (probably partial) block */
00545         k8 = (const rpmuint8_t *)k;
00546         switch (size) {
00547         case 12:
00548             c += k[4]+(((rpmuint32_t)k[5])<<16);
00549             b += k[2]+(((rpmuint32_t)k[3])<<16);
00550             a += k[0]+(((rpmuint32_t)k[1])<<16);
00551             break;
00552         case 11:
00553             c += ((rpmuint32_t)k8[10])<<16;
00554             /*@fallthrough@*/
00555         case 10:
00556             c += k[4];
00557             b += k[2]+(((rpmuint32_t)k[3])<<16);
00558             a += k[0]+(((rpmuint32_t)k[1])<<16);
00559             break;
00560         case  9:
00561             c += k8[8];
00562             /*@fallthrough@*/
00563         case  8:
00564             b += k[2]+(((rpmuint32_t)k[3])<<16);
00565             a += k[0]+(((rpmuint32_t)k[1])<<16);
00566             break;
00567         case  7:
00568             b += ((rpmuint32_t)k8[6])<<16;
00569             /*@fallthrough@*/
00570         case  6:
00571             b += k[2];
00572             a += k[0]+(((rpmuint32_t)k[1])<<16);
00573             break;
00574         case  5:
00575             b += k8[4];
00576             /*@fallthrough@*/
00577         case  4:
00578             a += k[0]+(((rpmuint32_t)k[1])<<16);
00579             break;
00580         case  3:
00581             a += ((rpmuint32_t)k8[2])<<16;
00582             /*@fallthrough@*/
00583         case  2:
00584             a += k[0];
00585             break;
00586         case  1:
00587             a += k8[0];
00588             break;
00589         case  0:
00590             goto exit;
00591         }
00592 
00593     } else {            /* need to read the key one byte at a time */
00594         const rpmuint8_t *k = (const rpmuint8_t *)key;
00595 
00596         /*----------- all but the last block: affect some 32 bits of (a,b,c) */
00597         while (size > 12) {
00598             a += k[0];
00599             a += ((rpmuint32_t)k[1])<<8;
00600             a += ((rpmuint32_t)k[2])<<16;
00601             a += ((rpmuint32_t)k[3])<<24;
00602             b += k[4];
00603             b += ((rpmuint32_t)k[5])<<8;
00604             b += ((rpmuint32_t)k[6])<<16;
00605             b += ((rpmuint32_t)k[7])<<24;
00606             c += k[8];
00607             c += ((rpmuint32_t)k[9])<<8;
00608             c += ((rpmuint32_t)k[10])<<16;
00609             c += ((rpmuint32_t)k[11])<<24;
00610             _JLU3_MIX(a,b,c);
00611             size -= 12;
00612             k += 12;
00613         }
00614 
00615         /*---------------------------- last block: affect all 32 bits of (c) */
00616         switch (size) {
00617         case 12:        c += ((rpmuint32_t)k[11])<<24;  /*@fallthrough@*/
00618         case 11:        c += ((rpmuint32_t)k[10])<<16;  /*@fallthrough@*/
00619         case 10:        c += ((rpmuint32_t)k[9])<<8;    /*@fallthrough@*/
00620         case  9:        c += k[8];                      /*@fallthrough@*/
00621         case  8:        b += ((rpmuint32_t)k[7])<<24;   /*@fallthrough@*/
00622         case  7:        b += ((rpmuint32_t)k[6])<<16;   /*@fallthrough@*/
00623         case  6:        b += ((rpmuint32_t)k[5])<<8;    /*@fallthrough@*/
00624         case  5:        b += k[4];                      /*@fallthrough@*/
00625         case  4:        a += ((rpmuint32_t)k[3])<<24;   /*@fallthrough@*/
00626         case  3:        a += ((rpmuint32_t)k[2])<<16;   /*@fallthrough@*/
00627         case  2:        a += ((rpmuint32_t)k[1])<<8;    /*@fallthrough@*/
00628         case  1:        a += k[0];                      /*@fallthrough@*/
00629             break;
00630         case  0:
00631             goto exit;
00632         }
00633     }
00634 
00635     _JLU3_FINAL(a,b,c);
00636 
00637 exit:
00638     *pc = c;
00639     *pb = b;
00640     return;
00641 }
00642 #endif  /* defined(_JLU3_jlu32lpair) */
00643 
00644 #if defined(_JLU3_jlu32b)
00645 rpmuint32_t jlu32b(rpmuint32_t h, /*@null@*/ const void *key, size_t size)
00646         /*@*/;
00647 /*
00648  * jlu32b():
00649  * This is the same as jlu32w() on big-endian machines.  It is different
00650  * from jlu32l() on all machines.  jlu32b() takes advantage of
00651  * big-endian byte ordering. 
00652  *
00653  * @param h             the previous hash, or an arbitrary value
00654  * @param *k            the key, an array of rpmuint8_t values
00655  * @param size          the size of the key
00656  * @return              the lookup3 hash
00657  */
00658 rpmuint32_t jlu32b(rpmuint32_t h, const void *key, size_t size)
00659 {
00660     union { const void *ptr; size_t i; } u;
00661     rpmuint32_t a = _JLU3_INIT(h, size);
00662     rpmuint32_t b = a;
00663     rpmuint32_t c = a;
00664 
00665     if (key == NULL)
00666         return h;
00667 
00668     u.ptr = key;
00669     if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
00670         const rpmuint32_t *k = (const rpmuint32_t *)key;        /* read 32-bit chunks */
00671 #ifdef  VALGRIND
00672         const rpmuint8_t  *k8;
00673 #endif
00674 
00675         /*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
00676         while (size > 12) {
00677             a += k[0];
00678             b += k[1];
00679             c += k[2];
00680             _JLU3_MIX(a,b,c);
00681             size -= 12;
00682             k += 3;
00683         }
00684 
00685         /*------------------------- handle the last (probably partial) block */
00686         /* 
00687          * "k[2]<<8" actually reads beyond the end of the string, but
00688          * then shifts out the part it's not allowed to read.  Because the
00689          * string is aligned, the illegal read is in the same word as the
00690          * rest of the string.  Every machine with memory protection I've seen
00691          * does it on word boundaries, so is OK with this.  But VALGRIND will
00692          * still catch it and complain.  The masking trick does make the hash
00693          * noticably faster for short strings (like English words).
00694          */
00695 #ifndef VALGRIND
00696 
00697         switch (size) {
00698         case 12:        c += k[2]; b+=k[1]; a+=k[0]; break;
00699         case 11:        c += k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
00700         case 10:        c += k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
00701         case  9:        c += k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
00702         case  8:        b += k[1]; a+=k[0]; break;
00703         case  7:        b += k[1]&0xffffff00; a+=k[0]; break;
00704         case  6:        b += k[1]&0xffff0000; a+=k[0]; break;
00705         case  5:        b += k[1]&0xff000000; a+=k[0]; break;
00706         case  4:        a += k[0]; break;
00707         case  3:        a += k[0]&0xffffff00; break;
00708         case  2:        a += k[0]&0xffff0000; break;
00709         case  1:        a += k[0]&0xff000000; break;
00710         case  0:        goto exit;
00711     }
00712 
00713 #else  /* make valgrind happy */
00714 
00715         k8 = (const rpmuint8_t *)k;
00716         switch (size) { /* all the case statements fall through */
00717         case 12:        c += k[2]; b+=k[1]; a+=k[0];    break;
00718         case 11:        c += ((rpmuint32_t)k8[10])<<8;  /*@fallthrough@*/
00719         case 10:        c += ((rpmuint32_t)k8[9])<<16;  /*@fallthrough@*/
00720         case  9:        c += ((rpmuint32_t)k8[8])<<24;  /*@fallthrough@*/
00721         case  8:        b += k[1]; a+=k[0];             break;
00722         case  7:        b += ((rpmuint32_t)k8[6])<<8;   /*@fallthrough@*/
00723         case  6:        b += ((rpmuint32_t)k8[5])<<16;  /*@fallthrough@*/
00724         case  5:        b += ((rpmuint32_t)k8[4])<<24;  /*@fallthrough@*/
00725         case  4:        a += k[0];                      break;
00726         case  3:        a += ((rpmuint32_t)k8[2])<<8;   /*@fallthrough@*/
00727         case  2:        a += ((rpmuint32_t)k8[1])<<16;  /*@fallthrough@*/
00728         case  1:        a += ((rpmuint32_t)k8[0])<<24;  break;
00729         case  0:        goto exit;
00730     }
00731 
00732 #endif /* !VALGRIND */
00733 
00734     } else {                        /* need to read the key one byte at a time */
00735         const rpmuint8_t *k = (const rpmuint8_t *)key;
00736 
00737         /*----------- all but the last block: affect some 32 bits of (a,b,c) */
00738         while (size > 12) {
00739             a += ((rpmuint32_t)k[0])<<24;
00740             a += ((rpmuint32_t)k[1])<<16;
00741             a += ((rpmuint32_t)k[2])<<8;
00742             a += ((rpmuint32_t)k[3]);
00743             b += ((rpmuint32_t)k[4])<<24;
00744             b += ((rpmuint32_t)k[5])<<16;
00745             b += ((rpmuint32_t)k[6])<<8;
00746             b += ((rpmuint32_t)k[7]);
00747             c += ((rpmuint32_t)k[8])<<24;
00748             c += ((rpmuint32_t)k[9])<<16;
00749             c += ((rpmuint32_t)k[10])<<8;
00750             c += ((rpmuint32_t)k[11]);
00751             _JLU3_MIX(a,b,c);
00752             size -= 12;
00753             k += 12;
00754         }
00755 
00756         /*---------------------------- last block: affect all 32 bits of (c) */
00757         switch (size) { /* all the case statements fall through */
00758         case 12:        c += k[11];                     /*@fallthrough@*/
00759         case 11:        c += ((rpmuint32_t)k[10])<<8;   /*@fallthrough@*/
00760         case 10:        c += ((rpmuint32_t)k[9])<<16;   /*@fallthrough@*/
00761         case  9:        c += ((rpmuint32_t)k[8])<<24;   /*@fallthrough@*/
00762         case  8:        b += k[7];                      /*@fallthrough@*/
00763         case  7:        b += ((rpmuint32_t)k[6])<<8;    /*@fallthrough@*/
00764         case  6:        b += ((rpmuint32_t)k[5])<<16;   /*@fallthrough@*/
00765         case  5:        b += ((rpmuint32_t)k[4])<<24;   /*@fallthrough@*/
00766         case  4:        a += k[3];                      /*@fallthrough@*/
00767         case  3:        a += ((rpmuint32_t)k[2])<<8;    /*@fallthrough@*/
00768         case  2:        a += ((rpmuint32_t)k[1])<<16;   /*@fallthrough@*/
00769         case  1:        a += ((rpmuint32_t)k[0])<<24;   /*@fallthrough@*/
00770             break;
00771         case  0:
00772             goto exit;
00773         }
00774     }
00775 
00776     _JLU3_FINAL(a,b,c);
00777 
00778 exit:
00779     return c;
00780 }
00781 #endif  /* defined(_JLU3_jlu32b) */
00782 
00783 #if defined(_JLU3_SELFTEST)
00784 
00785 /* used for timings */
00786 static void driver1(void)
00787         /*@*/
00788 {
00789     rpmuint8_t buf[256];
00790     rpmuint32_t i;
00791     rpmuint32_t h=0;
00792     time_t a,z;
00793 
00794     time(&a);
00795     for (i=0; i<256; ++i) buf[i] = 'x';
00796     for (i=0; i<1; ++i) {
00797         h = jlu32l(h, &buf[0], sizeof(buf[0]));
00798     }
00799     time(&z);
00800     if (z-a > 0) printf("time %d %.8x\n", (int)(z-a), h);
00801 }
00802 
00803 /* check that every input bit changes every output bit half the time */
00804 #define HASHSTATE 1
00805 #define HASHLEN   1
00806 #define MAXPAIR 60
00807 #define MAXLEN  70
00808 static void driver2(void)
00809         /*@*/
00810 {
00811     rpmuint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1];
00812     rpmuint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z;
00813     rpmuint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE];
00814     rpmuint32_t x[HASHSTATE],y[HASHSTATE];
00815     rpmuint32_t hlen;
00816 
00817     printf("No more than %d trials should ever be needed \n",MAXPAIR/2);
00818     for (hlen=0; hlen < MAXLEN; ++hlen) {
00819         z=0;
00820         for (i=0; i<hlen; ++i) {        /*-------------- for each input byte, */
00821             for (j=0; j<8; ++j) {       /*--------------- for each input bit, */
00822                 for (m=1; m<8; ++m) {   /*--- for serveral possible initvals, */
00823                     for (l=0; l<HASHSTATE; ++l)
00824                         e[l]=f[l]=g[l]=h[l]=x[l]=y[l]=~((rpmuint32_t)0);
00825 
00826                     /* check that every output bit is affected by that input bit */
00827                     for (k=0; k<MAXPAIR; k+=2) { 
00828                         rpmuint32_t finished=1;
00829                         /* keys have one bit different */
00830                         for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (rpmuint8_t)0;}
00831                         /* have a and b be two keys differing in only one bit */
00832                         a[i] ^= (k<<j);
00833                         a[i] ^= (k>>(8-j));
00834                         c[0] = jlu32l(m, a, hlen);
00835                         b[i] ^= ((k+1)<<j);
00836                         b[i] ^= ((k+1)>>(8-j));
00837                         d[0] = jlu32l(m, b, hlen);
00838                         /* check every bit is 1, 0, set, and not set at least once */
00839                         for (l=0; l<HASHSTATE; ++l) {
00840                             e[l] &= (c[l]^d[l]);
00841                             f[l] &= ~(c[l]^d[l]);
00842                             g[l] &= c[l];
00843                             h[l] &= ~c[l];
00844                             x[l] &= d[l];
00845                             y[l] &= ~d[l];
00846                             if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0;
00847                         }
00848                         if (finished) break;
00849                     }
00850                     if (k>z) z=k;
00851                     if (k == MAXPAIR) {
00852                         printf("Some bit didn't change: ");
00853                         printf("%.8x %.8x %.8x %.8x %.8x %.8x  ",
00854                                 e[0],f[0],g[0],h[0],x[0],y[0]);
00855                         printf("i %d j %d m %d len %d\n", i, j, m, hlen);
00856                     }
00857                     if (z == MAXPAIR) goto done;
00858                 }
00859             }
00860         }
00861    done:
00862         if (z < MAXPAIR) {
00863             printf("Mix success  %2d bytes  %2d initvals  ",i,m);
00864             printf("required  %d  trials\n", z/2);
00865         }
00866     }
00867     printf("\n");
00868 }
00869 
00870 /* Check for reading beyond the end of the buffer and alignment problems */
00871 static void driver3(void)
00872         /*@*/
00873 {
00874     rpmuint8_t buf[MAXLEN+20], *b;
00875     rpmuint32_t len;
00876     rpmuint8_t q[] = "This is the time for all good men to come to the aid of their country...";
00877     rpmuint32_t h;
00878     rpmuint8_t qq[] = "xThis is the time for all good men to come to the aid of their country...";
00879     rpmuint32_t i;
00880     rpmuint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country...";
00881     rpmuint32_t j;
00882     rpmuint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country...";
00883     rpmuint32_t ref,x,y;
00884     rpmuint8_t *p;
00885     rpmuint32_t m = 13;
00886 
00887     printf("Endianness.  These lines should all be the same (for values filled in):\n");
00888     printf("%.8x                            %.8x                            %.8x\n",
00889         jlu32w(m, (const rpmuint32_t *)q, (sizeof(q)-1)/4),
00890         jlu32w(m, (const rpmuint32_t *)q, (sizeof(q)-5)/4),
00891         jlu32w(m, (const rpmuint32_t *)q, (sizeof(q)-9)/4));
00892     p = q;
00893     printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
00894         jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
00895         jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
00896         jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
00897         jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
00898         jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
00899         jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
00900     p = &qq[1];
00901     printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
00902         jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
00903         jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
00904         jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
00905         jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
00906         jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
00907         jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
00908     p = &qqq[2];
00909     printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
00910         jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
00911         jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
00912         jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
00913         jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
00914         jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
00915         jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
00916     p = &qqqq[3];
00917     printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
00918         jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
00919         jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
00920         jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
00921         jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
00922         jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
00923         jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
00924     printf("\n");
00925     for (h=0, b=buf+1; h<8; ++h, ++b) {
00926         for (i=0; i<MAXLEN; ++i) {
00927             len = i;
00928             for (j=0; j<i; ++j)
00929                 *(b+j)=0;
00930 
00931             /* these should all be equal */
00932             m = 1;
00933             ref = jlu32l(m, b, len);
00934             *(b+i)=(rpmuint8_t)~0;
00935             *(b-1)=(rpmuint8_t)~0;
00936             x = jlu32l(m, b, len);
00937             y = jlu32l(m, b, len);
00938             if ((ref != x) || (ref != y)) 
00939                 printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y, h, i);
00940         }
00941     }
00942 }
00943 
00944 /* check for problems with nulls */
00945 static void driver4(void)
00946         /*@*/
00947 {
00948     rpmuint8_t buf[1];
00949     rpmuint32_t h;
00950     rpmuint32_t i;
00951     rpmuint32_t state[HASHSTATE];
00952 
00953     buf[0] = ~0;
00954     for (i=0; i<HASHSTATE; ++i)
00955         state[i] = 1;
00956     printf("These should all be different\n");
00957     h = 0;
00958     for (i=0; i<8; ++i) {
00959         h = jlu32l(h, buf, 0);
00960         printf("%2ld  0-byte strings, hash is  %.8x\n", (long)i, h);
00961     }
00962 }
00963 
00964 
00965 int main(int argc, char ** argv)
00966 {
00967     driver1();  /* test that the key is hashed: used for timings */
00968     driver2();  /* test that whole key is hashed thoroughly */
00969     driver3();  /* test that nothing but the key is hashed */
00970     driver4();  /* test hashing multiple buffers (all buffers are null) */
00971     return 1;
00972 }
00973 
00974 #endif  /* _JLU3_SELFTEST */

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