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/* -------------------------------------------------------------------- */
/*
* lookup3.c, by Bob Jenkins, May 2006, Public Domain.
*
* These are functions for producing 32-bit hashes for hash table lookup.
* jlu32w(), jlu32l(), jlu32lpair(), jlu32b(), _JLU3_MIX(), and _JLU3_FINAL()
* are externally useful functions. Routines to test the hash are included
* if SELF_TEST is defined. You can use this free for any purpose. It's in
* the public domain. It has no warranty.
*
* You probably want to use jlu32l(). jlu32l() and jlu32b()
* hash byte arrays. jlu32l() is is faster than jlu32b() on
* little-endian machines. Intel and AMD are little-endian machines.
* On second thought, you probably want jlu32lpair(), which is identical to
* jlu32l() except it returns two 32-bit hashes for the price of one.
* You could implement jlu32bpair() if you wanted but I haven't bothered here.
*
* If you want to find a hash of, say, exactly 7 integers, do
* a = i1; b = i2; c = i3;
* _JLU3_MIX(a,b,c);
* a += i4; b += i5; c += i6;
* _JLU3_MIX(a,b,c);
* a += i7;
* _JLU3_FINAL(a,b,c);
* then use c as the hash value. If you have a variable size array of
* 4-byte integers to hash, use jlu32w(). If you have a byte array (like
* a character string), use jlu32l(). If you have several byte arrays, or
* a mix of things, see the comments above jlu32l().
*
* Why is this so big? I read 12 bytes at a time into 3 4-byte integers,
* then mix those integers. This is fast (you can do a lot more thorough
* mixing with 12*3 instructions on 3 integers than you can with 3 instructions
* on 1 byte), but shoehorning those bytes into integers efficiently is messy.
*/
/* -------------------------------------------------------------------- */
#include <stdint.h>
#if defined(_JLU3_SELFTEST)
# define _JLU3_jlu32w 1
# define _JLU3_jlu32l 1
# define _JLU3_jlu32lpair 1
# define _JLU3_jlu32b 1
#endif
/*@-redef@*/
/*@unchecked@*/
static const union _dbswap {
const uint32_t ui;
const unsigned char uc[4];
} endian = { 0x11223344 };
# define HASH_LITTLE_ENDIAN (endian.uc[0] == (unsigned char) 0x44)
# define HASH_BIG_ENDIAN (endian.uc[0] == (unsigned char) 0x11)
/*@=redef@*/
#ifndef ROTL32
# define ROTL32(x, s) (((x) << (s)) | ((x) >> (32 - (s))))
#endif
/* NOTE: The _size parameter should be in bytes. */
#define _JLU3_INIT(_h, _size) (0xdeadbeef + ((uint32_t)(_size)) + (_h))
/* -------------------------------------------------------------------- */
/*
* _JLU3_MIX -- mix 3 32-bit values reversibly.
*
* This is reversible, so any information in (a,b,c) before _JLU3_MIX() is
* still in (a,b,c) after _JLU3_MIX().
*
* If four pairs of (a,b,c) inputs are run through _JLU3_MIX(), or through
* _JLU3_MIX() in reverse, there are at least 32 bits of the output that
* are sometimes the same for one pair and different for another pair.
* This was tested for:
* * pairs that differed by one bit, by two bits, in any combination
* of top bits of (a,b,c), or in any combination of bottom bits of
* (a,b,c).
* * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
* the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
* is commonly produced by subtraction) look like a single 1-bit
* difference.
* * the base values were pseudorandom, all zero but one bit set, or
* all zero plus a counter that starts at zero.
*
* Some k values for my "a-=c; a^=ROTL32(c,k); c+=b;" arrangement that
* satisfy this are
* 4 6 8 16 19 4
* 9 15 3 18 27 15
* 14 9 3 7 17 3
* Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
* for "differ" defined as + with a one-bit base and a two-bit delta. I
* used http://burtleburtle.net/bob/hash/avalanche.html to choose
* the operations, constants, and arrangements of the variables.
*
* This does not achieve avalanche. There are input bits of (a,b,c)
* that fail to affect some output bits of (a,b,c), especially of a. The
* most thoroughly mixed value is c, but it doesn't really even achieve
* avalanche in c.
*
* This allows some parallelism. Read-after-writes are good at doubling
* the number of bits affected, so the goal of mixing pulls in the opposite
* direction as the goal of parallelism. I did what I could. Rotates
* seem to cost as much as shifts on every machine I could lay my hands
* on, and rotates are much kinder to the top and bottom bits, so I used
* rotates.
*/
/* -------------------------------------------------------------------- */
#define _JLU3_MIX(a,b,c) \
{ \
a -= c; a ^= ROTL32(c, 4); c += b; \
b -= a; b ^= ROTL32(a, 6); a += c; \
c -= b; c ^= ROTL32(b, 8); b += a; \
a -= c; a ^= ROTL32(c,16); c += b; \
b -= a; b ^= ROTL32(a,19); a += c; \
c -= b; c ^= ROTL32(b, 4); b += a; \
}
/* -------------------------------------------------------------------- */
/**
* _JLU3_FINAL -- final mixing of 3 32-bit values (a,b,c) into c
*
* Pairs of (a,b,c) values differing in only a few bits will usually
* produce values of c that look totally different. This was tested for
* * pairs that differed by one bit, by two bits, in any combination
* of top bits of (a,b,c), or in any combination of bottom bits of
* (a,b,c).
* * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
* the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
* is commonly produced by subtraction) look like a single 1-bit
* difference.
* * the base values were pseudorandom, all zero but one bit set, or
* all zero plus a counter that starts at zero.
*
* These constants passed:
* 14 11 25 16 4 14 24
* 12 14 25 16 4 14 24
* and these came close:
* 4 8 15 26 3 22 24
* 10 8 15 26 3 22 24
* 11 8 15 26 3 22 24
*/
/* -------------------------------------------------------------------- */
#define _JLU3_FINAL(a,b,c) \
{ \
c ^= b; c -= ROTL32(b,14); \
a ^= c; a -= ROTL32(c,11); \
b ^= a; b -= ROTL32(a,25); \
c ^= b; c -= ROTL32(b,16); \
a ^= c; a -= ROTL32(c,4); \
b ^= a; b -= ROTL32(a,14); \
c ^= b; c -= ROTL32(b,24); \
}
#if defined(_JLU3_jlu32w)
uint32_t jlu32w(uint32_t h, /*@null@*/ const uint32_t *k, size_t size)
/*@*/;
/* -------------------------------------------------------------------- */
/**
* This works on all machines. To be useful, it requires
* -- that the key be an array of uint32_t's, and
* -- that the size be the number of uint32_t's in the key
*
* The function jlu32w() is identical to jlu32l() on little-endian
* machines, and identical to jlu32b() on big-endian machines,
* except that the size has to be measured in uint32_ts rather than in
* bytes. jlu32l() is more complicated than jlu32w() only because
* jlu32l() has to dance around fitting the key bytes into registers.
*
* @param h the previous hash, or an arbitrary value
* @param *k the key, an array of uint32_t values
* @param size the size of the key, in uint32_ts
* @return the lookup3 hash
*/
/* -------------------------------------------------------------------- */
uint32_t jlu32w(uint32_t h, const uint32_t *k, size_t size)
{
uint32_t a = _JLU3_INIT(h, (size * sizeof(*k)));
uint32_t b = a;
uint32_t c = a;
if (k == NULL)
goto exit;
/*----------------------------------------------- handle most of the key */
while (size > 3) {
a += k[0];
b += k[1];
c += k[2];
_JLU3_MIX(a,b,c);
size -= 3;
k += 3;
}
/*----------------------------------------- handle the last 3 uint32_t's */
switch (size) {
case 3 : c+=k[2];
case 2 : b+=k[1];
case 1 : a+=k[0];
_JLU3_FINAL(a,b,c);
/*@fallthrough@*/
case 0:
break;
}
/*---------------------------------------------------- report the result */
exit:
return c;
}
#endif /* defined(_JLU3_jlu32w) */
#if defined(_JLU3_jlu32l)
uint32_t jlu32l(uint32_t h, const void *key, size_t size)
/*@*/;
/* -------------------------------------------------------------------- */
/*
* jlu32l() -- hash a variable-length key into a 32-bit value
* h : can be any 4-byte value
* k : the key (the unaligned variable-length array of bytes)
* size : the size of the key, counting by bytes
* Returns a 32-bit value. Every bit of the key affects every bit of
* the return value. Two keys differing by one or two bits will have
* totally different hash values.
*
* The best hash table sizes are powers of 2. There is no need to do
* mod a prime (mod is sooo slow!). If you need less than 32 bits,
* use a bitmask. For example, if you need only 10 bits, do
* h = (h & hashmask(10));
* In which case, the hash table should have hashsize(10) elements.
*
* If you are hashing n strings (uint8_t **)k, do it like this:
* for (i=0, h=0; i<n; ++i) h = jlu32l(h, k[i], len[i]);
*
* By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this
* code any way you wish, private, educational, or commercial. It's free.
*
* Use for hash table lookup, or anything where one collision in 2^^32 is
* acceptable. Do NOT use for cryptographic purposes.
*
* @param h the previous hash, or an arbitrary value
* @param *k the key, an array of uint8_t values
* @param size the size of the key
* @return the lookup3 hash
*/
/* -------------------------------------------------------------------- */
uint32_t jlu32l(uint32_t h, const void *key, size_t size)
{
union { const void *ptr; size_t i; } u;
uint32_t a = _JLU3_INIT(h, size);
uint32_t b = a;
uint32_t c = a;
if (key == NULL)
goto exit;
u.ptr = key;
if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
#ifdef VALGRIND
const uint8_t *k8;
#endif
/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
while (size > 12) {
a += k[0];
b += k[1];
c += k[2];
_JLU3_MIX(a,b,c);
size -= 12;
k += 3;
}
/*------------------------- handle the last (probably partial) block */
/*
* "k[2]&0xffffff" actually reads beyond the end of the string, but
* then masks off the part it's not allowed to read. Because the
* string is aligned, the masked-off tail is in the same word as the
* rest of the string. Every machine with memory protection I've seen
* does it on word boundaries, so is OK with this. But VALGRIND will
* still catch it and complain. The masking trick does make the hash
* noticably faster for short strings (like English words).
*/
#ifndef VALGRIND
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
case 10: c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
case 9: c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
case 8: b += k[1]; a+=k[0]; break;
case 7: b += k[1]&0xffffff; a+=k[0]; break;
case 6: b += k[1]&0xffff; a+=k[0]; break;
case 5: b += k[1]&0xff; a+=k[0]; break;
case 4: a += k[0]; break;
case 3: a += k[0]&0xffffff; break;
case 2: a += k[0]&0xffff; break;
case 1: a += k[0]&0xff; break;
case 0: goto exit;
}
#else /* make valgrind happy */
k8 = (const uint8_t *)k;
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0] break;
case 11: c += ((uint32_t)k8[10])<<16; /*@fallthrough@*/
case 10: c += ((uint32_t)k8[9])<<8; /*@fallthrough@*/
case 9: c += k8[8]; /*@fallthrough@*/
case 8: b += k[1]; a+=k[0]; break;
case 7: b += ((uint32_t)k8[6])<<16; /*@fallthrough@*/
case 6: b += ((uint32_t)k8[5])<<8; /*@fallthrough@*/
case 5: b += k8[4]; /*@fallthrough@*/
case 4: a += k[0]; break;
case 3: a += ((uint32_t)k8[2])<<16; /*@fallthrough@*/
case 2: a += ((uint32_t)k8[1])<<8; /*@fallthrough@*/
case 1: a += k8[0]; break;
case 0: goto exit;
}
#endif /* !valgrind */
} else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
const uint8_t *k8;
/*----------- all but last block: aligned reads and different mixing */
while (size > 12) {
a += k[0] + (((uint32_t)k[1])<<16);
b += k[2] + (((uint32_t)k[3])<<16);
c += k[4] + (((uint32_t)k[5])<<16);
_JLU3_MIX(a,b,c);
size -= 12;
k += 6;
}
/*------------------------- handle the last (probably partial) block */
k8 = (const uint8_t *)k;
switch (size) {
case 12:
c += k[4]+(((uint32_t)k[5])<<16);
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 11:
c += ((uint32_t)k8[10])<<16;
/*@fallthrough@*/
case 10:
c += (uint32_t)k[4];
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 9:
c += (uint32_t)k8[8];
/*@fallthrough@*/
case 8:
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 7:
b += ((uint32_t)k8[6])<<16;
/*@fallthrough@*/
case 6:
b += (uint32_t)k[2];
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 5:
b += (uint32_t)k8[4];
/*@fallthrough@*/
case 4:
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 3:
a += ((uint32_t)k8[2])<<16;
/*@fallthrough@*/
case 2:
a += (uint32_t)k[0];
break;
case 1:
a += (uint32_t)k8[0];
break;
case 0:
goto exit;
}
} else { /* need to read the key one byte at a time */
const uint8_t *k = (const uint8_t *)key;
/*----------- all but the last block: affect some 32 bits of (a,b,c) */
while (size > 12) {
a += (uint32_t)k[0];
a += ((uint32_t)k[1])<<8;
a += ((uint32_t)k[2])<<16;
a += ((uint32_t)k[3])<<24;
b += (uint32_t)k[4];
b += ((uint32_t)k[5])<<8;
b += ((uint32_t)k[6])<<16;
b += ((uint32_t)k[7])<<24;
c += (uint32_t)k[8];
c += ((uint32_t)k[9])<<8;
c += ((uint32_t)k[10])<<16;
c += ((uint32_t)k[11])<<24;
_JLU3_MIX(a,b,c);
size -= 12;
k += 12;
}
/*---------------------------- last block: affect all 32 bits of (c) */
switch (size) {
case 12: c += ((uint32_t)k[11])<<24; /*@fallthrough@*/
case 11: c += ((uint32_t)k[10])<<16; /*@fallthrough@*/
case 10: c += ((uint32_t)k[9])<<8; /*@fallthrough@*/
case 9: c += (uint32_t)k[8]; /*@fallthrough@*/
case 8: b += ((uint32_t)k[7])<<24; /*@fallthrough@*/
case 7: b += ((uint32_t)k[6])<<16; /*@fallthrough@*/
case 6: b += ((uint32_t)k[5])<<8; /*@fallthrough@*/
case 5: b += (uint32_t)k[4]; /*@fallthrough@*/
case 4: a += ((uint32_t)k[3])<<24; /*@fallthrough@*/
case 3: a += ((uint32_t)k[2])<<16; /*@fallthrough@*/
case 2: a += ((uint32_t)k[1])<<8; /*@fallthrough@*/
case 1: a += (uint32_t)k[0];
break;
case 0:
goto exit;
}
}
_JLU3_FINAL(a,b,c);
exit:
return c;
}
#endif /* defined(_JLU3_jlu32l) */
#if defined(_JLU3_jlu32lpair)
/**
* jlu32lpair: return 2 32-bit hash values.
*
* This is identical to jlu32l(), except it returns two 32-bit hash
* values instead of just one. This is good enough for hash table
* lookup with 2^^64 buckets, or if you want a second hash if you're not
* happy with the first, or if you want a probably-unique 64-bit ID for
* the key. *pc is better mixed than *pb, so use *pc first. If you want
* a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
*
* @param h the previous hash, or an arbitrary value
* @param *key the key, an array of uint8_t values
* @param size the size of the key in bytes
* @retval *pc, IN: primary initval, OUT: primary hash
* *retval *pb IN: secondary initval, OUT: secondary hash
*/
void jlu32lpair(const void *key, size_t size, uint32_t *pc, uint32_t *pb)
{
union { const void *ptr; size_t i; } u;
uint32_t a = _JLU3_INIT(*pc, size);
uint32_t b = a;
uint32_t c = a;
if (key == NULL)
goto exit;
c += *pb; /* Add the secondary hash. */
u.ptr = key;
if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
#ifdef VALGRIND
const uint8_t *k8;
#endif
/*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
while (size > (size_t)12) {
a += k[0];
b += k[1];
c += k[2];
_JLU3_MIX(a,b,c);
size -= 12;
k += 3;
}
/*------------------------- handle the last (probably partial) block */
/*
* "k[2]&0xffffff" actually reads beyond the end of the string, but
* then masks off the part it's not allowed to read. Because the
* string is aligned, the masked-off tail is in the same word as the
* rest of the string. Every machine with memory protection I've seen
* does it on word boundaries, so is OK with this. But VALGRIND will
* still catch it and complain. The masking trick does make the hash
* noticably faster for short strings (like English words).
*/
#ifndef VALGRIND
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
case 10: c += k[2]&0xffff; b+=k[1]; a+=k[0]; break;
case 9: c += k[2]&0xff; b+=k[1]; a+=k[0]; break;
case 8: b += k[1]; a+=k[0]; break;
case 7: b += k[1]&0xffffff; a+=k[0]; break;
case 6: b += k[1]&0xffff; a+=k[0]; break;
case 5: b += k[1]&0xff; a+=k[0]; break;
case 4: a += k[0]; break;
case 3: a += k[0]&0xffffff; break;
case 2: a += k[0]&0xffff; break;
case 1: a += k[0]&0xff; break;
case 0: goto exit;
}
#else /* make valgrind happy */
k8 = (const uint8_t *)k;
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += ((uint32_t)k8[10])<<16; /*@fallthrough@*/
case 10: c += ((uint32_t)k8[9])<<8; /*@fallthrough@*/
case 9: c += k8[8]; /*@fallthrough@*/
case 8: b += k[1]; a+=k[0]; break;
case 7: b += ((uint32_t)k8[6])<<16; /*@fallthrough@*/
case 6: b += ((uint32_t)k8[5])<<8; /*@fallthrough@*/
case 5: b += k8[4]; /*@fallthrough@*/
case 4: a += k[0]; break;
case 3: a += ((uint32_t)k8[2])<<16; /*@fallthrough@*/
case 2: a += ((uint32_t)k8[1])<<8; /*@fallthrough@*/
case 1: a += k8[0]; break;
case 0: goto exit;
}
#endif /* !valgrind */
} else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
const uint8_t *k8;
/*----------- all but last block: aligned reads and different mixing */
while (size > (size_t)12) {
a += k[0] + (((uint32_t)k[1])<<16);
b += k[2] + (((uint32_t)k[3])<<16);
c += k[4] + (((uint32_t)k[5])<<16);
_JLU3_MIX(a,b,c);
size -= 12;
k += 6;
}
/*------------------------- handle the last (probably partial) block */
k8 = (const uint8_t *)k;
switch (size) {
case 12:
c += k[4]+(((uint32_t)k[5])<<16);
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 11:
c += ((uint32_t)k8[10])<<16;
/*@fallthrough@*/
case 10:
c += k[4];
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 9:
c += k8[8];
/*@fallthrough@*/
case 8:
b += k[2]+(((uint32_t)k[3])<<16);
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 7:
b += ((uint32_t)k8[6])<<16;
/*@fallthrough@*/
case 6:
b += k[2];
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 5:
b += k8[4];
/*@fallthrough@*/
case 4:
a += k[0]+(((uint32_t)k[1])<<16);
break;
case 3:
a += ((uint32_t)k8[2])<<16;
/*@fallthrough@*/
case 2:
a += k[0];
break;
case 1:
a += k8[0];
break;
case 0:
goto exit;
}
} else { /* need to read the key one byte at a time */
const uint8_t *k = (const uint8_t *)key;
/*----------- all but the last block: affect some 32 bits of (a,b,c) */
while (size > (size_t)12) {
a += k[0];
a += ((uint32_t)k[1])<<8;
a += ((uint32_t)k[2])<<16;
a += ((uint32_t)k[3])<<24;
b += k[4];
b += ((uint32_t)k[5])<<8;
b += ((uint32_t)k[6])<<16;
b += ((uint32_t)k[7])<<24;
c += k[8];
c += ((uint32_t)k[9])<<8;
c += ((uint32_t)k[10])<<16;
c += ((uint32_t)k[11])<<24;
_JLU3_MIX(a,b,c);
size -= 12;
k += 12;
}
/*---------------------------- last block: affect all 32 bits of (c) */
switch (size) {
case 12: c += ((uint32_t)k[11])<<24; /*@fallthrough@*/
case 11: c += ((uint32_t)k[10])<<16; /*@fallthrough@*/
case 10: c += ((uint32_t)k[9])<<8; /*@fallthrough@*/
case 9: c += k[8]; /*@fallthrough@*/
case 8: b += ((uint32_t)k[7])<<24; /*@fallthrough@*/
case 7: b += ((uint32_t)k[6])<<16; /*@fallthrough@*/
case 6: b += ((uint32_t)k[5])<<8; /*@fallthrough@*/
case 5: b += k[4]; /*@fallthrough@*/
case 4: a += ((uint32_t)k[3])<<24; /*@fallthrough@*/
case 3: a += ((uint32_t)k[2])<<16; /*@fallthrough@*/
case 2: a += ((uint32_t)k[1])<<8; /*@fallthrough@*/
case 1: a += k[0];
break;
case 0:
goto exit;
}
}
_JLU3_FINAL(a,b,c);
exit:
*pc = c;
*pb = b;
return;
}
#endif /* defined(_JLU3_jlu32lpair) */
#if defined(_JLU3_jlu32b)
uint32_t jlu32b(uint32_t h, /*@null@*/ const void *key, size_t size)
/*@*/;
/*
* jlu32b():
* This is the same as jlu32w() on big-endian machines. It is different
* from jlu32l() on all machines. jlu32b() takes advantage of
* big-endian byte ordering.
*
* @param h the previous hash, or an arbitrary value
* @param *k the key, an array of uint8_t values
* @param size the size of the key
* @return the lookup3 hash
*/
uint32_t jlu32b(uint32_t h, const void *key, size_t size)
{
union { const void *ptr; size_t i; } u;
uint32_t a = _JLU3_INIT(h, size);
uint32_t b = a;
uint32_t c = a;
if (key == NULL)
return h;
u.ptr = key;
if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
#ifdef VALGRIND
const uint8_t *k8;
#endif
/*-- all but last block: aligned reads and affect 32 bits of (a,b,c) */
while (size > 12) {
a += k[0];
b += k[1];
c += k[2];
_JLU3_MIX(a,b,c);
size -= 12;
k += 3;
}
/*------------------------- handle the last (probably partial) block */
/*
* "k[2]<<8" actually reads beyond the end of the string, but
* then shifts out the part it's not allowed to read. Because the
* string is aligned, the illegal read is in the same word as the
* rest of the string. Every machine with memory protection I've seen
* does it on word boundaries, so is OK with this. But VALGRIND will
* still catch it and complain. The masking trick does make the hash
* noticably faster for short strings (like English words).
*/
#ifndef VALGRIND
switch (size) {
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
case 10: c += k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
case 9: c += k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
case 8: b += k[1]; a+=k[0]; break;
case 7: b += k[1]&0xffffff00; a+=k[0]; break;
case 6: b += k[1]&0xffff0000; a+=k[0]; break;
case 5: b += k[1]&0xff000000; a+=k[0]; break;
case 4: a += k[0]; break;
case 3: a += k[0]&0xffffff00; break;
case 2: a += k[0]&0xffff0000; break;
case 1: a += k[0]&0xff000000; break;
case 0: goto exit;
}
#else /* make valgrind happy */
k8 = (const uint8_t *)k;
switch (size) { /* all the case statements fall through */
case 12: c += k[2]; b+=k[1]; a+=k[0]; break;
case 11: c += ((uint32_t)k8[10])<<8; /*@fallthrough@*/
case 10: c += ((uint32_t)k8[9])<<16; /*@fallthrough@*/
case 9: c += ((uint32_t)k8[8])<<24; /*@fallthrough@*/
case 8: b += k[1]; a+=k[0]; break;
case 7: b += ((uint32_t)k8[6])<<8; /*@fallthrough@*/
case 6: b += ((uint32_t)k8[5])<<16; /*@fallthrough@*/
case 5: b += ((uint32_t)k8[4])<<24; /*@fallthrough@*/
case 4: a += k[0]; break;
case 3: a += ((uint32_t)k8[2])<<8; /*@fallthrough@*/
case 2: a += ((uint32_t)k8[1])<<16; /*@fallthrough@*/
case 1: a += ((uint32_t)k8[0])<<24; break;
case 0: goto exit;
}
#endif /* !VALGRIND */
} else { /* need to read the key one byte at a time */
const uint8_t *k = (const uint8_t *)key;
/*----------- all but the last block: affect some 32 bits of (a,b,c) */
while (size > 12) {
a += ((uint32_t)k[0])<<24;
a += ((uint32_t)k[1])<<16;
a += ((uint32_t)k[2])<<8;
a += ((uint32_t)k[3]);
b += ((uint32_t)k[4])<<24;
b += ((uint32_t)k[5])<<16;
b += ((uint32_t)k[6])<<8;
b += ((uint32_t)k[7]);
c += ((uint32_t)k[8])<<24;
c += ((uint32_t)k[9])<<16;
c += ((uint32_t)k[10])<<8;
c += ((uint32_t)k[11]);
_JLU3_MIX(a,b,c);
size -= 12;
k += 12;
}
/*---------------------------- last block: affect all 32 bits of (c) */
switch (size) { /* all the case statements fall through */
case 12: c += k[11]; /*@fallthrough@*/
case 11: c += ((uint32_t)k[10])<<8; /*@fallthrough@*/
case 10: c += ((uint32_t)k[9])<<16; /*@fallthrough@*/
case 9: c += ((uint32_t)k[8])<<24; /*@fallthrough@*/
case 8: b += k[7]; /*@fallthrough@*/
case 7: b += ((uint32_t)k[6])<<8; /*@fallthrough@*/
case 6: b += ((uint32_t)k[5])<<16; /*@fallthrough@*/
case 5: b += ((uint32_t)k[4])<<24; /*@fallthrough@*/
case 4: a += k[3]; /*@fallthrough@*/
case 3: a += ((uint32_t)k[2])<<8; /*@fallthrough@*/
case 2: a += ((uint32_t)k[1])<<16; /*@fallthrough@*/
case 1: a += ((uint32_t)k[0])<<24; /*@fallthrough@*/
break;
case 0:
goto exit;
}
}
_JLU3_FINAL(a,b,c);
exit:
return c;
}
#endif /* defined(_JLU3_jlu32b) */
#if defined(_JLU3_SELFTEST)
/* used for timings */
static void driver1(void)
/*@*/
{
uint8_t buf[256];
uint32_t i;
uint32_t h=0;
time_t a,z;
time(&a);
for (i=0; i<256; ++i) buf[i] = 'x';
for (i=0; i<1; ++i) {
h = jlu32l(h, &buf[0], sizeof(buf[0]));
}
time(&z);
if (z-a > 0) printf("time %d %.8x\n", (int)(z-a), h);
}
/* check that every input bit changes every output bit half the time */
#define HASHSTATE 1
#define HASHLEN 1
#define MAXPAIR 60
#define MAXLEN 70
static void driver2(void)
/*@*/
{
uint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1];
uint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z;
uint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE];
uint32_t x[HASHSTATE],y[HASHSTATE];
uint32_t hlen;
printf("No more than %d trials should ever be needed \n",MAXPAIR/2);
for (hlen=0; hlen < MAXLEN; ++hlen) {
z=0;
for (i=0; i<hlen; ++i) { /*-------------- for each input byte, */
for (j=0; j<8; ++j) { /*--------------- for each input bit, */
for (m=1; m<8; ++m) { /*--- for serveral possible initvals, */
for (l=0; l<HASHSTATE; ++l)
e[l]=f[l]=g[l]=h[l]=x[l]=y[l]=~((uint32_t)0);
/* check that every output bit is affected by that input bit */
for (k=0; k<MAXPAIR; k+=2) {
uint32_t finished=1;
/* keys have one bit different */
for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (uint8_t)0;}
/* have a and b be two keys differing in only one bit */
a[i] ^= (k<<j);
a[i] ^= (k>>(8-j));
c[0] = jlu32l(m, a, hlen);
b[i] ^= ((k+1)<<j);
b[i] ^= ((k+1)>>(8-j));
d[0] = jlu32l(m, b, hlen);
/* check every bit is 1, 0, set, and not set at least once */
for (l=0; l<HASHSTATE; ++l) {
e[l] &= (c[l]^d[l]);
f[l] &= ~(c[l]^d[l]);
g[l] &= c[l];
h[l] &= ~c[l];
x[l] &= d[l];
y[l] &= ~d[l];
if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0;
}
if (finished) break;
}
if (k>z) z=k;
if (k == MAXPAIR) {
printf("Some bit didn't change: ");
printf("%.8x %.8x %.8x %.8x %.8x %.8x ",
e[0],f[0],g[0],h[0],x[0],y[0]);
printf("i %d j %d m %d len %d\n", i, j, m, hlen);
}
if (z == MAXPAIR) goto done;
}
}
}
done:
if (z < MAXPAIR) {
printf("Mix success %2d bytes %2d initvals ",i,m);
printf("required %d trials\n", z/2);
}
}
printf("\n");
}
/* Check for reading beyond the end of the buffer and alignment problems */
static void driver3(void)
/*@*/
{
uint8_t buf[MAXLEN+20], *b;
uint32_t len;
uint8_t q[] = "This is the time for all good men to come to the aid of their country...";
uint32_t h;
uint8_t qq[] = "xThis is the time for all good men to come to the aid of their country...";
uint32_t i;
uint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country...";
uint32_t j;
uint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country...";
uint32_t ref,x,y;
uint8_t *p;
uint32_t m = 13;
printf("Endianness. These lines should all be the same (for values filled in):\n");
printf("%.8x %.8x %.8x\n",
jlu32w(m, (const uint32_t *)q, (sizeof(q)-1)/4),
jlu32w(m, (const uint32_t *)q, (sizeof(q)-5)/4),
jlu32w(m, (const uint32_t *)q, (sizeof(q)-9)/4));
p = q;
printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
p = &qq[1];
printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
p = &qqq[2];
printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
p = &qqqq[3];
printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
jlu32l(m, p, sizeof(q)-1), jlu32l(m, p, sizeof(q)-2),
jlu32l(m, p, sizeof(q)-3), jlu32l(m, p, sizeof(q)-4),
jlu32l(m, p, sizeof(q)-5), jlu32l(m, p, sizeof(q)-6),
jlu32l(m, p, sizeof(q)-7), jlu32l(m, p, sizeof(q)-8),
jlu32l(m, p, sizeof(q)-9), jlu32l(m, p, sizeof(q)-10),
jlu32l(m, p, sizeof(q)-11), jlu32l(m, p, sizeof(q)-12));
printf("\n");
for (h=0, b=buf+1; h<8; ++h, ++b) {
for (i=0; i<MAXLEN; ++i) {
len = i;
for (j=0; j<i; ++j)
*(b+j)=0;
/* these should all be equal */
m = 1;
ref = jlu32l(m, b, len);
*(b+i)=(uint8_t)~0;
*(b-1)=(uint8_t)~0;
x = jlu32l(m, b, len);
y = jlu32l(m, b, len);
if ((ref != x) || (ref != y))
printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y, h, i);
}
}
}
/* check for problems with nulls */
static void driver4(void)
/*@*/
{
uint8_t buf[1];
uint32_t h;
uint32_t i;
uint32_t state[HASHSTATE];
buf[0] = ~0;
for (i=0; i<HASHSTATE; ++i)
state[i] = 1;
printf("These should all be different\n");
h = 0;
for (i=0; i<8; ++i) {
h = jlu32l(h, buf, 0);
printf("%2ld 0-byte strings, hash is %.8x\n", (long)i, h);
}
}
int main(int argc, char ** argv)
{
driver1(); /* test that the key is hashed: used for timings */
driver2(); /* test that whole key is hashed thoroughly */
driver3(); /* test that nothing but the key is hashed */
driver4(); /* test hashing multiple buffers (all buffers are null) */
return 1;
}
#endif /* _JLU3_SELFTEST */