Added the SRANDMEMBER key <count> variant.

[redis.git] / src / t_zset.c

diff --git a/src/t_zset.c b/src/t_zset.c
index 7008f0c4aec93b7ac581f89779af928707c67d7a..4812709e19048c67acc25ab337fcc30d3e48ac8f 100644 (file)
--- a/src/t_zset.c
+++ b/src/t_zset.c
@@ -17,7 +17,7 @@
 /* This skiplist implementation is almost a C translation of the original
  * algorithm described by William Pugh in "Skip Lists: A Probabilistic
  * Alternative to Balanced Trees", modified in three ways:
- * a) this implementation allows for repeated values.
+ * a) this implementation allows for repeated scores.
  * b) the comparison is not just by key (our 'score') but by satellite data.
  * c) there is a back pointer, so it's a doubly linked list with the back
  * pointers being only at "level 1". This allows to traverse the list
@@ -64,6 +64,10 @@ void zslFree(zskiplist *zsl) {
     zfree(zsl);
 }
 
+/* Returns a random level for the new skiplist node we are going to create.
+ * The return value of this function is between 1 and ZSKIPLIST_MAXLEVEL
+ * (both inclusive), with a powerlaw-alike distribution where higher
+ * levels are less likely to be returned. */
 int zslRandomLevel(void) {
     int level = 1;
     while ((random()&0xFFFF) < (ZSKIPLIST_P * 0xFFFF))
@@ -498,7 +502,7 @@ int zzlIsInRange(unsigned char *zl, zrangespec *range) {
         return 0;
 
     p = ziplistIndex(zl,-1); /* Last score. */
-    redisAssert(p != NULL);
+    if (p == NULL) return 0; /* Empty sorted set */
     score = zzlGetScore(p);
     if (!zslValueGteMin(score,range))
         return 0;
@@ -1250,13 +1254,16 @@ int zuiNext(zsetopsrc *op, zsetopval *val) {
     if (val->flags & OPVAL_DIRTY_ROBJ)
         decrRefCount(val->ele);
 
-    bzero(val,sizeof(zsetopval));
+    memset(val,0,sizeof(zsetopval));
 
     if (op->type == REDIS_SET) {
         iterset *it = &op->iter.set;
         if (op->encoding == REDIS_ENCODING_INTSET) {
-            if (!intsetGet(it->is.is,it->is.ii,(int64_t*)&val->ell))
+            int64_t ell;
+
+            if (!intsetGet(it->is.is,it->is.ii,&ell))
                 return 0;
+            val->ell = ell;
             val->score = 1.0;
 
             /* Move to next element. */
@@ -1545,6 +1552,8 @@ void zunionInterGenericCommand(redisClient *c, robj *dstkey, int op) {
                 double score, value;
 
                 score = src[0].weight * zval.score;
+                if (isnan(score)) score = 0;
+
                 for (j = 1; j < setnum; j++) {
                     /* It is not safe to access the zset we are
                      * iterating, so explicitly check for equal object. */
@@ -1587,6 +1596,7 @@ void zunionInterGenericCommand(redisClient *c, robj *dstkey, int op) {
 
                 /* Initialize score */
                 score = src[i].weight * zval.score;
+                if (isnan(score)) score = 0;
 
                 /* Because the inputs are sorted by size, it's only possible
                  * for sets at larger indices to hold this element. */