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
+ val2 : IN: can be any 4-byte value OUT: second 32 bit hash.
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.
+totally different hash values. Note that the return value is better
+mixed than val2, so use that first.
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,
-------------------------------------------------------------------------------
*/
-static uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
+static uint32_t hashlittle( const void *key, size_t length, uint32_t *val2 )
{
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;
+ a = b = c = 0xdeadbeef + ((uint32_t)length) + *val2;
u.ptr = key;
if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
}
final(a,b,c);
+ *val2 = b;
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)
+static uint32_t hashbig( const void *key, size_t length, uint32_t *val2)
{
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;
+ a = b = c = 0xdeadbeef + ((uint32_t)length) + *val2;
u.ptr = key;
if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
}
final(a,b,c);
+ *val2 = b;
return c;
}
* element. This delivers least-surprise: hash such as "int arr[] = {
* 1, 2 }; hash_stable(arr, 2, 0);" will be the same on big and little
* endian machines, even though a bytewise hash wouldn't be. */
-uint32_t hash_stable_64(const void *key, size_t n, uint32_t base)
+uint64_t hash64_stable_64(const void *key, size_t n, uint64_t base)
{
const uint64_t *k = key;
uint32_t a,b,c;
/* Set up the internal state */
- a = b = c = 0xdeadbeef + ((uint32_t)n*8) + base;
+ a = b = c = 0xdeadbeef + ((uint32_t)n*8) + (base >> 32) + base;
while (n > 3) {
a += (uint32_t)k[0];
return c;
}
final(a,b,c);
- return c;
+ return ((uint64_t)b << 32) | c;
}
-uint32_t hash_stable_32(const void *key, size_t n, uint32_t base)
+uint64_t hash64_stable_32(const void *key, size_t n, uint64_t base)
{
const uint32_t *k = key;
uint32_t a,b,c;
/* Set up the internal state */
- a = b = c = 0xdeadbeef + ((uint32_t)n*4) + base;
+ a = b = c = 0xdeadbeef + ((uint32_t)n*4) + (base >> 32) + base;
while (n > 3) {
a += k[0];
return c;
}
final(a,b,c);
- return c;
+ return ((uint64_t)b << 32) | c;
}
-uint32_t hash_stable_16(const void *key, size_t n, uint32_t base)
+uint64_t hash64_stable_16(const void *key, size_t n, uint64_t base)
{
const uint16_t *k = key;
uint32_t a,b,c;
/* Set up the internal state */
- a = b = c = 0xdeadbeef + ((uint32_t)n*2) + base;
+ a = b = c = 0xdeadbeef + ((uint32_t)n*2) + (base >> 32) + base;
while (n > 6) {
a += (uint32_t)k[0] + ((uint32_t)k[1] << 16);
return c;
}
final(a,b,c);
- return c;
+ return ((uint64_t)b << 32) | c;
}
-
-uint32_t hash_stable_8(const void *key, size_t n, uint32_t base)
+
+uint64_t hash64_stable_8(const void *key, size_t n, uint64_t base)
{
- return hashlittle(key, n, base);
+ uint32_t b32 = base + (base >> 32);
+ uint32_t lower = hashlittle(key, n, &b32);
+
+ return ((uint64_t)b32 << 32) | lower;
}
uint32_t hash_any(const void *key, size_t length, uint32_t base)
{
if (HASH_BIG_ENDIAN)
- return hashbig(key, length, base);
+ return hashbig(key, length, &base);
else
- return hashlittle(key, length, base);
+ return hashlittle(key, length, &base);
+}
+
+uint32_t hash_stable_64(const void *key, size_t n, uint32_t base)
+{
+ return hash64_stable_64(key, n, base);
+}
+
+uint32_t hash_stable_32(const void *key, size_t n, uint32_t base)
+{
+ return hash64_stable_32(key, n, base);
+}
+
+uint32_t hash_stable_16(const void *key, size_t n, uint32_t base)
+{
+ return hash64_stable_16(key, n, base);
+}
+
+uint32_t hash_stable_8(const void *key, size_t n, uint32_t base)
+{
+ return hashlittle(key, n, &base);
+}
+
+/* Jenkins' lookup8 is a 64 bit hash, but he says it's obsolete. Use
+ * the plain one and recombine into 64 bits. */
+uint64_t hash64_any(const void *key, size_t length, uint64_t base)
+{
+ uint32_t b32 = base + (base >> 32);
+ uint32_t lower;
+
+ if (HASH_BIG_ENDIAN)
+ lower = hashbig(key, length, &b32);
+ else
+ lower = hashlittle(key, length, &b32);
+
+ return ((uint64_t)b32 << 32) | lower;
}
#ifdef SELF_TEST
projects / ccan / blobdiff