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fix hash functions, especially for rationals and cons cells, and maybe for bytes and strings

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svn: r7020
This commit is contained in:
Matthew Flatt 2007-08-04 14:02:22 +00:00
parent a4ec1349b1
commit a2d33dceb4
1 changed files with 22 additions and 8 deletions
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30
src/mzscheme/src/hash.c
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@ -862,6 +862,10 @@ static Scheme_Object *hash_k(void)
#define MZ_HASH_K hash_k #define MZ_HASH_K hash_k
#define MZ_HASH_I1 (k - t) #define MZ_HASH_I1 (k - t)
/* Based on Bob Jenkins's one-at-a-time hash function at
http://www.burtleburtle.net/bob/hash/doobs.html: */
#define MZ_MIX(k) (k += (k << 10), k ^= (k >> 6))
static long equal_hash_key(Scheme_Object *o, long k) static long equal_hash_key(Scheme_Object *o, long k)
{ {
Scheme_Type t; Scheme_Type t;
@ -963,7 +967,8 @@ static long equal_hash_key(Scheme_Object *o, long k)
char *s = SCHEME_BYTE_STR_VAL(o); char *s = SCHEME_BYTE_STR_VAL(o);
while (i--) { while (i--) {
k = (k << 5) + k + s[i]; k += s[i];
MZ_MIX(k);
} }
return k; return k;
@ -974,7 +979,8 @@ static long equal_hash_key(Scheme_Object *o, long k)
mzchar *s = SCHEME_CHAR_STR_VAL(o); mzchar *s = SCHEME_CHAR_STR_VAL(o);
while (i--) { while (i--) {
k = (k << 5) + k + s[i]; k += s[i];
MZ_MIX(k);
} }
return k; return k;
@ -992,7 +998,7 @@ static long equal_hash_key(Scheme_Object *o, long k)
for (i = SCHEME_STRUCT_NUM_SLOTS(s1); i--; ) { for (i = SCHEME_STRUCT_NUM_SLOTS(s1); i--; ) {
k += equal_hash_key(s1->slots[i], 0); k += equal_hash_key(s1->slots[i], 0);
k = (k << 5) + k; MZ_MIX(k);
} }
return k; return k;
@ -1012,6 +1018,7 @@ static long equal_hash_key(Scheme_Object *o, long k)
Scheme_Hash_Table *ht = (Scheme_Hash_Table *)o; Scheme_Hash_Table *ht = (Scheme_Hash_Table *)o;
Scheme_Object **vals, **keys; Scheme_Object **vals, **keys;
int i; int i;
long vk;
# include "mzhashchk.inc" # include "mzhashchk.inc"
@ -1021,8 +1028,11 @@ static long equal_hash_key(Scheme_Object *o, long k)
vals = ht->vals; vals = ht->vals;
for (i = ht->size; i--; ) { for (i = ht->size; i--; ) {
if (vals[i]) { if (vals[i]) {
k += equal_hash_key(keys[i], 0); vk = equal_hash_key(keys[i], 0);
k += (equal_hash_key(vals[i], 0) << 1); MZ_MIX(vk);
vk += equal_hash_key(vals[i], 0);
MZ_MIX(vk);
k += vk; /* can't mix k, because the key order shouldn't matter */
} }
} }
@ -1034,6 +1044,7 @@ static long equal_hash_key(Scheme_Object *o, long k)
Scheme_Bucket **buckets, *bucket; Scheme_Bucket **buckets, *bucket;
const char *key; const char *key;
int i, weak; int i, weak;
long vk;
# include "mzhashchk.inc" # include "mzhashchk.inc"
@ -1051,8 +1062,11 @@ static long equal_hash_key(Scheme_Object *o, long k)
key = bucket->key; key = bucket->key;
} }
if (key) { if (key) {
k += (equal_hash_key((Scheme_Object *)bucket->val, 0) << 1); vk = equal_hash_key((Scheme_Object *)bucket->val, 0);
k += equal_hash_key((Scheme_Object *)key, 0); MZ_MIX(vk);
vk += equal_hash_key((Scheme_Object *)key, 0);
MZ_MIX(vk);
k += vk; /* can't mix k, because the key order shouldn't matter */
} }
} }
} }
@ -1092,7 +1106,7 @@ static long equal_hash_key(Scheme_Object *o, long k)
} }
} }
k = (k << 1) + k; MZ_MIX(k);
goto top; goto top;
} }