func (db *DB) zRange(key []byte, min int64, max int64, offset int, count int, reverse bool) ([]ScorePair, error) {
if len(key) > MaxKeySize {
return nil, errKeySize
}
if offset < 0 {
return []ScorePair{}, nil
}
nv := 64
if count > 0 {
nv = count
}
v := make([]ScorePair, 0, nv)
var it *leveldb.RangeLimitIterator
//if reverse and offset is 0, count < 0, we may use forward iterator then reverse
//because leveldb iterator prev is slower than next
if !reverse || (offset == 0 && count < 0) {
it = db.zIterator(key, min, max, offset, count, false)
} else {
it = db.zIterator(key, min, max, offset, count, true)
}
for ; it.Valid(); it.Next() {
_, m, s, err := db.zDecodeScoreKey(it.Key())
//may be we will check key equal?
if err != nil {
continue
}
v = append(v, ScorePair{Member: m, Score: s})
}
it.Close()
if reverse && (offset == 0 && count < 0) {
for i, j := 0, len(v)-1; i < j; i, j = i+1, j-1 {
v[i], v[j] = v[j], v[i]
}
}
return v, nil
}
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.db.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 *leveldb.RangeLimitIterator
sk := db.zEncodeScoreKey(key, member, s)
if !reverse {
minKey := db.zEncodeStartScoreKey(key, MinScore)
rit = leveldb.NewRangeIterator(it, &leveldb.Range{minKey, sk, leveldb.RangeClose})
} else {
maxKey := db.zEncodeStopScoreKey(key, MaxScore)
rit = leveldb.NewRevRangeIterator(it, &leveldb.Range{sk, maxKey, leveldb.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
}