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https://github.com/fluencelabs/redis
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5e3dcc522b
commit
170e41464d
54
src/dict.c
54
src/dict.c
@ -666,34 +666,42 @@ dictEntry *dictGetRandomKey(dict *d)
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* at producing N elements, and the elements are guaranteed to be non
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* repeating. */
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unsigned int dictGetRandomKeys(dict *d, dictEntry **des, unsigned int count) {
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int j; /* internal hash table id, 0 or 1. */
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unsigned int stored = 0;
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unsigned int j; /* internal hash table id, 0 or 1. */
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unsigned int tables; /* 1 or 2 tables? */
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unsigned int stored = 0, maxsizemask;
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if (dictSize(d) < count) count = dictSize(d);
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while(stored < count) {
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for (j = 0; j < 2; j++) {
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/* Pick a random point inside the hash table 0 or 1. */
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unsigned int i = random() & d->ht[j].sizemask;
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int size = d->ht[j].size;
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/* Make sure to visit every bucket by iterating 'size' times. */
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while(size--) {
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dictEntry *he = d->ht[j].table[i];
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while (he) {
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/* Collect all the elements of the buckets found non
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* empty while iterating. */
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*des = he;
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des++;
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he = he->next;
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stored++;
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if (stored == count) return stored;
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}
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i = (i+1) & d->ht[j].sizemask;
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/* Try to do a rehashing work proportional to 'count'. */
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for (j = 0; j < count; j++) {
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if (dictIsRehashing(d))
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_dictRehashStep(d);
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else
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break;
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}
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tables = dictIsRehashing(d) ? 2 : 1;
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maxsizemask = d->ht[0].sizemask;
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if (tables > 1 && maxsizemask < d->ht[1].sizemask)
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maxsizemask = d->ht[1].sizemask;
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/* Pick a random point inside the larger table. */
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unsigned int i = random() & maxsizemask;
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while(stored < count) {
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for (j = 0; j < tables; j++) {
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if (i >= d->ht[j].size) continue; /* Out of range for this table. */
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dictEntry *he = d->ht[j].table[i];
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while (he) {
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/* Collect all the elements of the buckets found non
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* empty while iterating. */
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*des = he;
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des++;
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he = he->next;
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stored++;
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if (stored == count) return stored;
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}
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/* If there is only one table and we iterated it all, we should
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* already have 'count' elements. Assert this condition. */
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assert(dictIsRehashing(d) != 0);
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}
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i = (i+1) & maxsizemask;
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}
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return stored; /* Never reached. */
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}
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