Merge remote-tracking branch 'origin/unstable' into unstable

[redis.git] / src / t_zset.c

diff --git a/src/t_zset.c b/src/t_zset.c
index f42e5a3185bcf7b44f147c5b0871e7457099703a..d2535c72794baa95cbbd77048f8e78cb7489ef5f 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))