+++ /dev/null
-/*
--------------------------------------------------------------------------------
-lookup3.c, by Bob Jenkins, May 2006, Public Domain.
-
-These are functions for producing 32-bit hashes for hash table lookup.
-hash_word(), 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 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 hash_word(). 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
-
-#if 0
-#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 */
-#endif
-
-#include "hash/hash.h"
-#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 hash_word() 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 hash_word() only because
- hashlittle() has to dance around fitting the key bytes into registers.
---------------------------------------------------------------------
-*/
-uint32_t hash_u32(
-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;
-}
-
-
-#if 0
-/*
---------------------------------------------------------------------
-hash_word2() -- same as hash_word(), 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 hash_word().
---------------------------------------------------------------------
-*/
-void hash_word2 (
-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;
-}
-#endif
-
-/*
--------------------------------------------------------------------------------
-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.
--------------------------------------------------------------------------------
-*/
-
-static uint32_t 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 */
-#ifdef VALGRIND
- const uint8_t *k8;
-#endif
-
- /*------ 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
- * noticably 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 */
-
- 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;
-}
-
-#if 0
-/*
- * 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 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 */
- const uint8_t *k8;
-
- /*------ 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
- * noticably 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 */
-
- 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;
-}
-#endif
-
-
-/*
- * hashbig():
- * This is the same as hash_word() on big-endian machines. It is different
- * from hashlittle() on all machines. hashbig() takes advantage of
- * big-endian byte ordering.
- */
-static uint32_t 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 */
-#ifdef VALGRIND
- const uint8_t *k8;
-#endif
-
- /*------ 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
- * noticably 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 */
-
- 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;
-}
-
-uint32_t hash_any_stable(const void *key, size_t length, uint32_t base)
-{
- /* We use hashlittle as our stable hash. */
- return hashlittle(key, length, base);
-}
-
-uint32_t hash_any(const void *key, size_t length, uint32_t base)
-{
- if (HASH_BIG_ENDIAN)
- return hashbig(key, length, base);
- else
- /* We call hash_any_stable not hashlittle. This way we know
- * that hashlittle will be inlined in hash_any_stable. */
- return hash_any_stable(key, length, base);
-}
-
-#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",
- hash_word((const uint32_t *)q, (sizeof(q)-1)/4, 13),
- hash_word((const uint32_t *)q, (sizeof(q)-5)/4, 13),
- hash_word((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 hash_word2 and hash_word produce the same results */
- len = 0xdeadbeef;
- i=47, j=0;
- hash_word2(&len, 1, &i, &j);
- if (hash_word(&len, 1, 47) != i)
- printf("hash_word2 and hash_word mismatch %x %x\n",
- i, hash_word(&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);
- }
-}
-
-
-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) */
- return 1;
-}
-
-#endif /* SELF_TEST */
projects / ccan / blobdiff