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Diffstat (limited to 'src/journal/lookup3.c')
| -rw-r--r-- | src/journal/lookup3.c | 1009 |
1 files changed, 0 insertions, 1009 deletions
diff --git a/src/journal/lookup3.c b/src/journal/lookup3.c deleted file mode 100644 index 52ffdf7b1d..0000000000 --- a/src/journal/lookup3.c +++ /dev/null @@ -1,1009 +0,0 @@ -/* Slightly modified by Lennart Poettering, to avoid name clashes, and - * unexport a few functions. */ - -#include "lookup3.h" - -/* -------------------------------------------------------------------------------- -lookup3.c, by Bob Jenkins, May 2006, Public Domain. - -These are functions for producing 32-bit hashes for hash table lookup. -hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and 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 hashlittle(). hashlittle() and hashbig() -hash byte arrays. hashlittle() is faster than hashbig() on -little-endian machines. Intel and AMD are little-endian machines. -On second thought, you probably want hashlittle2(), which is identical to -hashlittle() except it returns two 32-bit hashes for the price of one. -You could implement hashbig2() 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; - mix(a,b,c); - a += i4; b += i5; c += i6; - mix(a,b,c); - a += i7; - final(a,b,c); -then use c as the hash value. If you have a variable length array of -4-byte integers to hash, use hashword(). If you have a byte array (like -a character string), use hashlittle(). If you have several byte arrays, or -a mix of things, see the comments above hashlittle(). - -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. -------------------------------------------------------------------------------- -*/ -/* #define SELF_TEST 1 */ - -#include <stdio.h> /* defines printf for tests */ -#include <time.h> /* defines time_t for timings in the test */ -#include <stdint.h> /* defines uint32_t etc */ -#include <sys/param.h> /* attempt to define endianness */ -#ifdef linux -# include <endian.h> /* attempt to define endianness */ -#endif - -/* - * My best guess at if you are big-endian or little-endian. This may - * need adjustment. - */ -#if (defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && \ - __BYTE_ORDER == __LITTLE_ENDIAN) || \ - (defined(i386) || defined(__i386__) || defined(__i486__) || \ - defined(__i586__) || defined(__i686__) || defined(vax) || defined(MIPSEL)) -# define HASH_LITTLE_ENDIAN 1 -# define HASH_BIG_ENDIAN 0 -#elif (defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && \ - __BYTE_ORDER == __BIG_ENDIAN) || \ - (defined(sparc) || defined(POWERPC) || defined(mc68000) || defined(sel)) -# define HASH_LITTLE_ENDIAN 0 -# define HASH_BIG_ENDIAN 1 -#else -# define HASH_LITTLE_ENDIAN 0 -# define HASH_BIG_ENDIAN 0 -#endif - -#define hashsize(n) ((uint32_t)1<<(n)) -#define hashmask(n) (hashsize(n)-1) -#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) - -/* -------------------------------------------------------------------------------- -mix -- mix 3 32-bit values reversibly. - -This is reversible, so any information in (a,b,c) before mix() is -still in (a,b,c) after mix(). - -If four pairs of (a,b,c) inputs are run through mix(), or through -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^=rot(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 mix(a,b,c) \ -{ \ - a -= c; a ^= rot(c, 4); c += b; \ - b -= a; b ^= rot(a, 6); a += c; \ - c -= b; c ^= rot(b, 8); b += a; \ - a -= c; a ^= rot(c,16); c += b; \ - b -= a; b ^= rot(a,19); a += c; \ - c -= b; c ^= rot(b, 4); b += a; \ -} - -/* -------------------------------------------------------------------------------- -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 final(a,b,c) \ -{ \ - c ^= b; c -= rot(b,14); \ - a ^= c; a -= rot(c,11); \ - b ^= a; b -= rot(a,25); \ - c ^= b; c -= rot(b,16); \ - a ^= c; a -= rot(c,4); \ - b ^= a; b -= rot(a,14); \ - c ^= b; c -= rot(b,24); \ -} - -/* --------------------------------------------------------------------- - This works on all machines. To be useful, it requires - -- that the key be an array of uint32_t's, and - -- that the length be the number of uint32_t's in the key - - The function hashword() is identical to hashlittle() on little-endian - machines, and identical to hashbig() on big-endian machines, - except that the length has to be measured in uint32_ts rather than in - bytes. hashlittle() is more complicated than hashword() only because - hashlittle() has to dance around fitting the key bytes into registers. --------------------------------------------------------------------- -*/ -uint32_t jenkins_hashword( -const uint32_t *k, /* the key, an array of uint32_t values */ -size_t length, /* the length of the key, in uint32_ts */ -uint32_t initval) /* the previous hash, or an arbitrary value */ -{ - uint32_t a,b,c; - - /* Set up the internal state */ - a = b = c = 0xdeadbeef + (((uint32_t)length)<<2) + initval; - - /*------------------------------------------------- handle most of the key */ - while (length > 3) - { - a += k[0]; - b += k[1]; - c += k[2]; - mix(a,b,c); - length -= 3; - k += 3; - } - - /*------------------------------------------- handle the last 3 uint32_t's */ - switch(length) /* all the case statements fall through */ - { - case 3 : c+=k[2]; - case 2 : b+=k[1]; - case 1 : a+=k[0]; - final(a,b,c); - case 0: /* case 0: nothing left to add */ - break; - } - /*------------------------------------------------------ report the result */ - return c; -} - - -/* --------------------------------------------------------------------- -hashword2() -- same as hashword(), but take two seeds and return two -32-bit values. pc and pb must both be nonnull, and *pc and *pb must -both be initialized with seeds. If you pass in (*pb)==0, the output -(*pc) will be the same as the return value from hashword(). --------------------------------------------------------------------- -*/ -void jenkins_hashword2 ( -const uint32_t *k, /* the key, an array of uint32_t values */ -size_t length, /* the length of the key, in uint32_ts */ -uint32_t *pc, /* IN: seed OUT: primary hash value */ -uint32_t *pb) /* IN: more seed OUT: secondary hash value */ -{ - uint32_t a,b,c; - - /* Set up the internal state */ - a = b = c = 0xdeadbeef + ((uint32_t)(length<<2)) + *pc; - c += *pb; - - /*------------------------------------------------- handle most of the key */ - while (length > 3) - { - a += k[0]; - b += k[1]; - c += k[2]; - mix(a,b,c); - length -= 3; - k += 3; - } - - /*------------------------------------------- handle the last 3 uint32_t's */ - switch(length) /* all the case statements fall through */ - { - case 3 : c+=k[2]; - case 2 : b+=k[1]; - case 1 : a+=k[0]; - final(a,b,c); - case 0: /* case 0: nothing left to add */ - break; - } - /*------------------------------------------------------ report the result */ - *pc=c; *pb=b; -} - - -/* -------------------------------------------------------------------------------- -hashlittle() -- hash a variable-length key into a 32-bit value - k : the key (the unaligned variable-length array of bytes) - length : the length of the key, counting by bytes - initval : can be any 4-byte value -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 = hashlittle( k[i], len[i], h); - -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. -------------------------------------------------------------------------------- -*/ - -uint32_t jenkins_hashlittle( const void *key, size_t length, uint32_t initval) -{ - uint32_t a,b,c; /* internal state */ - union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */ - - /* Set up the internal state */ - a = b = c = 0xdeadbeef + ((uint32_t)length) + initval; - - u.ptr = key; - if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) { - const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */ - - /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */ - while (length > 12) - { - a += k[0]; - b += k[1]; - c += k[2]; - mix(a,b,c); - length -= 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 - * noticeably faster for short strings (like English words). - */ -#ifndef VALGRIND - - switch(length) - { - 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 : return c; /* zero length strings require no mixing */ - } - -#else /* make valgrind happy */ - { - const uint8_t *k8 = (const uint8_t *) k; - - switch(length) - { - case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; - case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ - case 10: c+=((uint32_t)k8[9])<<8; /* fall through */ - case 9 : c+=k8[8]; /* fall through */ - case 8 : b+=k[1]; a+=k[0]; break; - case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ - case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */ - case 5 : b+=k8[4]; /* fall through */ - case 4 : a+=k[0]; break; - case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ - case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */ - case 1 : a+=k8[0]; break; - case 0 : return c; - } - } - -#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 (length > 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); - mix(a,b,c); - length -= 12; - k += 6; - } - - /*----------------------------- handle the last (probably partial) block */ - k8 = (const uint8_t *)k; - switch(length) - { - 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; /* fall through */ - 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]; /* fall through */ - 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; /* fall through */ - case 6 : b+=k[2]; - a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 5 : b+=k8[4]; /* fall through */ - case 4 : a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ - case 2 : a+=k[0]; - break; - case 1 : a+=k8[0]; - break; - case 0 : return c; /* zero length requires no mixing */ - } - - } 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 (length > 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; - mix(a,b,c); - length -= 12; - k += 12; - } - - /*-------------------------------- last block: affect all 32 bits of (c) */ - switch(length) /* all the case statements fall through */ - { - case 12: c+=((uint32_t)k[11])<<24; - case 11: c+=((uint32_t)k[10])<<16; - case 10: c+=((uint32_t)k[9])<<8; - case 9 : c+=k[8]; - case 8 : b+=((uint32_t)k[7])<<24; - case 7 : b+=((uint32_t)k[6])<<16; - case 6 : b+=((uint32_t)k[5])<<8; - case 5 : b+=k[4]; - case 4 : a+=((uint32_t)k[3])<<24; - case 3 : a+=((uint32_t)k[2])<<16; - case 2 : a+=((uint32_t)k[1])<<8; - case 1 : a+=k[0]; - break; - case 0 : return c; - } - } - - final(a,b,c); - return c; -} - - -/* - * hashlittle2: return 2 32-bit hash values - * - * This is identical to hashlittle(), 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)". - */ -void jenkins_hashlittle2( - const void *key, /* the key to hash */ - size_t length, /* length of the key */ - uint32_t *pc, /* IN: primary initval, OUT: primary hash */ - uint32_t *pb) /* IN: secondary initval, OUT: secondary hash */ -{ - uint32_t a,b,c; /* internal state */ - union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */ - - /* Set up the internal state */ - a = b = c = 0xdeadbeef + ((uint32_t)length) + *pc; - c += *pb; - - u.ptr = key; - if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) { - const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */ - - /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */ - while (length > 12) - { - a += k[0]; - b += k[1]; - c += k[2]; - mix(a,b,c); - length -= 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 - * noticeably faster for short strings (like English words). - */ -#ifndef VALGRIND - - switch(length) - { - 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 : *pc=c; *pb=b; return; /* zero length strings require no mixing */ - } - -#else /* make valgrind happy */ - - { - const uint8_t *k8 = (const uint8_t *)k; - switch(length) - { - case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; - case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ - case 10: c+=((uint32_t)k8[9])<<8; /* fall through */ - case 9 : c+=k8[8]; /* fall through */ - case 8 : b+=k[1]; a+=k[0]; break; - case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ - case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */ - case 5 : b+=k8[4]; /* fall through */ - case 4 : a+=k[0]; break; - case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ - case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */ - case 1 : a+=k8[0]; break; - case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */ - } - } - -#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 (length > 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); - mix(a,b,c); - length -= 12; - k += 6; - } - - /*----------------------------- handle the last (probably partial) block */ - k8 = (const uint8_t *)k; - switch(length) - { - 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; /* fall through */ - 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]; /* fall through */ - 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; /* fall through */ - case 6 : b+=k[2]; - a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 5 : b+=k8[4]; /* fall through */ - case 4 : a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ - case 2 : a+=k[0]; - break; - case 1 : a+=k8[0]; - break; - case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */ - } - - } 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 (length > 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; - mix(a,b,c); - length -= 12; - k += 12; - } - - /*-------------------------------- last block: affect all 32 bits of (c) */ - switch(length) /* all the case statements fall through */ - { - case 12: c+=((uint32_t)k[11])<<24; - case 11: c+=((uint32_t)k[10])<<16; - case 10: c+=((uint32_t)k[9])<<8; - case 9 : c+=k[8]; - case 8 : b+=((uint32_t)k[7])<<24; - case 7 : b+=((uint32_t)k[6])<<16; - case 6 : b+=((uint32_t)k[5])<<8; - case 5 : b+=k[4]; - case 4 : a+=((uint32_t)k[3])<<24; - case 3 : a+=((uint32_t)k[2])<<16; - case 2 : a+=((uint32_t)k[1])<<8; - case 1 : a+=k[0]; - break; - case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */ - } - } - - final(a,b,c); - *pc=c; *pb=b; -} - - - -/* - * hashbig(): - * This is the same as hashword() on big-endian machines. It is different - * from hashlittle() on all machines. hashbig() takes advantage of - * big-endian byte ordering. - */ -uint32_t jenkins_hashbig( const void *key, size_t length, uint32_t initval) -{ - uint32_t a,b,c; - union { const void *ptr; size_t i; } u; /* to cast key to (size_t) happily */ - - /* Set up the internal state */ - a = b = c = 0xdeadbeef + ((uint32_t)length) + initval; - - u.ptr = key; - if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) { - const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */ - - /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */ - while (length > 12) - { - a += k[0]; - b += k[1]; - c += k[2]; - mix(a,b,c); - length -= 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 - * noticeably faster for short strings (like English words). - */ -#ifndef VALGRIND - - switch(length) - { - 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 : return c; /* zero length strings require no mixing */ - } - -#else /* make valgrind happy */ - - { - const uint8_t *k8 = (const uint8_t *)k; - switch(length) /* 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; /* fall through */ - case 10: c+=((uint32_t)k8[9])<<16; /* fall through */ - case 9 : c+=((uint32_t)k8[8])<<24; /* fall through */ - case 8 : b+=k[1]; a+=k[0]; break; - case 7 : b+=((uint32_t)k8[6])<<8; /* fall through */ - case 6 : b+=((uint32_t)k8[5])<<16; /* fall through */ - case 5 : b+=((uint32_t)k8[4])<<24; /* fall through */ - case 4 : a+=k[0]; break; - case 3 : a+=((uint32_t)k8[2])<<8; /* fall through */ - case 2 : a+=((uint32_t)k8[1])<<16; /* fall through */ - case 1 : a+=((uint32_t)k8[0])<<24; break; - case 0 : return c; - } - } - -#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 (length > 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]); - mix(a,b,c); - length -= 12; - k += 12; - } - - /*-------------------------------- last block: affect all 32 bits of (c) */ - switch(length) /* all the case statements fall through */ - { - case 12: c+=k[11]; - case 11: c+=((uint32_t)k[10])<<8; - case 10: c+=((uint32_t)k[9])<<16; - case 9 : c+=((uint32_t)k[8])<<24; - case 8 : b+=k[7]; - case 7 : b+=((uint32_t)k[6])<<8; - case 6 : b+=((uint32_t)k[5])<<16; - case 5 : b+=((uint32_t)k[4])<<24; - case 4 : a+=k[3]; - case 3 : a+=((uint32_t)k[2])<<8; - case 2 : a+=((uint32_t)k[1])<<16; - case 1 : a+=((uint32_t)k[0])<<24; - break; - case 0 : return c; - } - } - - final(a,b,c); - return c; -} - - -#ifdef SELF_TEST - -/* used for timings */ -void driver1() -{ - 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 = hashlittle(&buf[0],1,h); - } - time(&z); - if (z-a > 0) printf("time %d %.8x\n", 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 -void driver2() -{ - 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] = hashlittle(a, hlen, m); - b[i] ^= ((k+1)<<j); - b[i] ^= ((k+1)>>(8-j)); - d[0] = hashlittle(b, hlen, m); - /* 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 */ -void driver3() -{ - 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; - - printf("Endianness. These lines should all be the same (for values filled in):\n"); - printf("%.8x %.8x %.8x\n", - hashword((const uint32_t *)q, (sizeof(q)-1)/4, 13), - hashword((const uint32_t *)q, (sizeof(q)-5)/4, 13), - hashword((const uint32_t *)q, (sizeof(q)-9)/4, 13)); - p = q; - printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n", - hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13), - hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13), - hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13), - hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13), - hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13), - hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13)); - p = &qq[1]; - printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n", - hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13), - hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13), - hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13), - hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13), - hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13), - hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13)); - p = &qqq[2]; - printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n", - hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13), - hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13), - hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13), - hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13), - hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13), - hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13)); - p = &qqqq[3]; - printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n", - hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13), - hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13), - hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13), - hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13), - hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13), - hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13)); - printf("\n"); - - /* check that hashlittle2 and hashlittle produce the same results */ - i=47; j=0; - hashlittle2(q, sizeof(q), &i, &j); - if (hashlittle(q, sizeof(q), 47) != i) - printf("hashlittle2 and hashlittle mismatch\n"); - - /* check that hashword2 and hashword produce the same results */ - len = 0xdeadbeef; - i=47, j=0; - hashword2(&len, 1, &i, &j); - if (hashword(&len, 1, 47) != i) - printf("hashword2 and hashword mismatch %x %x\n", - i, hashword(&len, 1, 47)); - - /* check hashlittle doesn't read before or after the ends of the string */ - 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 */ - ref = hashlittle(b, len, (uint32_t)1); - *(b+i)=(uint8_t)~0; - *(b-1)=(uint8_t)~0; - x = hashlittle(b, len, (uint32_t)1); - y = hashlittle(b, len, (uint32_t)1); - if ((ref != x) || (ref != y)) - { - printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y, - h, i); - } - } - } -} - -/* check for problems with nulls */ - void driver4() -{ - uint8_t buf[1]; - uint32_t h,i,state[HASHSTATE]; - - - buf[0] = ~0; - for (i=0; i<HASHSTATE; ++i) state[i] = 1; - printf("These should all be different\n"); - for (i=0, h=0; i<8; ++i) - { - h = hashlittle(buf, 0, h); - printf("%2ld 0-byte strings, hash is %.8x\n", i, h); - } -} - -void driver5() -{ - uint32_t b,c; - b=0, c=0, hashlittle2("", 0, &c, &b); - printf("hash is %.8lx %.8lx\n", c, b); /* deadbeef deadbeef */ - b=0xdeadbeef, c=0, hashlittle2("", 0, &c, &b); - printf("hash is %.8lx %.8lx\n", c, b); /* bd5b7dde deadbeef */ - b=0xdeadbeef, c=0xdeadbeef, hashlittle2("", 0, &c, &b); - printf("hash is %.8lx %.8lx\n", c, b); /* 9c093ccd bd5b7dde */ - b=0, c=0, hashlittle2("Four score and seven years ago", 30, &c, &b); - printf("hash is %.8lx %.8lx\n", c, b); /* 17770551 ce7226e6 */ - b=1, c=0, hashlittle2("Four score and seven years ago", 30, &c, &b); - printf("hash is %.8lx %.8lx\n", c, b); /* e3607cae bd371de4 */ - b=0, c=1, hashlittle2("Four score and seven years ago", 30, &c, &b); - printf("hash is %.8lx %.8lx\n", c, b); /* cd628161 6cbea4b3 */ - c = hashlittle("Four score and seven years ago", 30, 0); - printf("hash is %.8lx\n", c); /* 17770551 */ - c = hashlittle("Four score and seven years ago", 30, 1); - printf("hash is %.8lx\n", c); /* cd628161 */ -} - - -int main() -{ - 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) */ - driver5(); /* test the hash against known vectors */ - return 1; -} - -#endif /* SELF_TEST */ |