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dict.c sub-hashing WIP.

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antirez 2016-09-07 15:28:30 +02:00
parent 5d4cd43ef8
commit e9ad6b39d8
1 changed files with 39 additions and 4 deletions
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43
src/dict.c
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@ -571,13 +571,48 @@ dictEntry *dictFind(dict *d, const void *key)
dv = d->ht[table].table[idx]; dv = d->ht[table].table[idx];
if (dv != NULL) { if (dv != NULL) {
uint32_t entries = dv->used + dv->free; uint32_t entries = dv->used + dv->free;
uint32_t j; /* In order to scan less entries, we use the entries vector
for (j = 0; j < entries; j++) { * as a sub hash table. The entry is not really guaranteed to
* be there, however we try to access it using this pattern and
* if possible we also swap the entries so that the next time
* we'll succeed in accessing the entry at the first try. */
unsigned int h2 = (h<<5)+(h>>16);
uint32_t j = h2 % entries, i = entries;
while(i--) {
dictEntry *he = dv->entry+j; dictEntry *he = dv->entry+j;
if (he->key == NULL || he->hash != h) continue; if (he->key == NULL || he->hash != h) {
if (key==he->key || dictCompareKeys(d, key, he->key)) j = (j+1) % entries;
continue;
}
if (key==he->key || dictCompareKeys(d, key, he->key)) {
#if 1
if (d->iterators == 0 && /* No interators with indexes. */
dict_can_resize && /* No copy on write concerns. */
i != entries-1 /* Not already in right place. */)
{
uint32_t destpos = h2 % entries;
uint32_t target_h2 = (dv->entry[destpos].hash << 5) +
(dv->entry[destpos].hash >> 16);
// printf("%d -> %d (%d)\n", (int)j, (int)destpos,
// (dv->entry[destpos].key == NULL) ? -1 :
// dv->entry[destpos].hash % entries);
/* Only swap if the entry we are going to replace is
* empty or is not in its final destination. */
if (dv->entry[destpos].key == NULL ||
(target_h2 % entries) != destpos)
{
// printf("From %d to %d\n", (int)j, (int)destpos);
dictEntry copy = *he;
dv->entry[j] = dv->entry[destpos];;
dv->entry[destpos] = copy;
he = dv->entry+destpos;
}
}
#endif
return he; return he;
} }
j = (j+1) % entries;
}
} }
if (!dictIsRehashing(d)) return NULL; if (!dictIsRehashing(d)) return NULL;
} }