func (db *DB) zrank(key []byte, member []byte, reverse bool) (int64, error) {
if err := checkZSetKMSize(key, member); err != nil {
return 0, err
}
k := db.zEncodeSetKey(key, member)
it := db.bucket.NewIterator()
defer it.Close()
if v := it.Find(k); v == nil {
return -1, nil
} else {
if s, err := Int64(v, nil); err != nil {
return 0, err
} else {
var rit *store.RangeLimitIterator
sk := db.zEncodeScoreKey(key, member, s)
if !reverse {
minKey := db.zEncodeStartScoreKey(key, MinScore)
rit = store.NewRangeIterator(it, &store.Range{minKey, sk, store.RangeClose})
} else {
maxKey := db.zEncodeStopScoreKey(key, MaxScore)
rit = store.NewRevRangeIterator(it, &store.Range{sk, maxKey, store.RangeClose})
}
var lastKey []byte = nil
var n int64 = 0
for ; rit.Valid(); rit.Next() {
n++
lastKey = rit.BufKey(lastKey)
}
if _, m, _, err := db.zDecodeScoreKey(lastKey); err == nil && bytes.Equal(m, member) {
n--
return n, nil
}
}
}
return -1, nil
}
