func (db *DB) zRange(key []byte, min int64, max int64, withScores bool, offset int, limit int, reverse bool) ([]interface{}, error) {
if len(key) > MaxKeySize {
return nil, ErrKeySize
}
if offset < 0 {
return []interface{}{}, nil
}
nv := 64
if limit > 0 {
nv = limit
}
if withScores {
nv = 2 * nv
}
v := make([]interface{}, 0, nv)
var it *leveldb.Iterator
//if reverse and offset is 0, limit < 0, we may use forward iterator then reverse
//because leveldb iterator prev is slower than next
if !reverse || (offset == 0 && limit < 0) {
it = db.zIterator(key, min, max, offset, limit, false)
} else {
it = db.zIterator(key, min, max, offset, limit, 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, m)
if withScores {
v = append(v, StrPutInt64(s))
}
}
if reverse && (offset == 0 && limit < 0) {
v = db.zReverse(v, withScores)
}
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)
if v, err := db.db.Get(k); err != nil {
return 0, err
} else if v == nil {
return -1, nil
} else {
if s, err := Int64(v, err); err != nil {
return 0, err
} else {
var it *leveldb.Iterator
sk := db.zEncodeScoreKey(key, member, s)
if !reverse {
minKey := db.zEncodeStartScoreKey(key, MinScore)
it = db.db.Iterator(minKey, sk, leveldb.RangeClose, 0, -1)
} else {
maxKey := db.zEncodeStopScoreKey(key, MaxScore)
it = db.db.RevIterator(sk, maxKey, leveldb.RangeClose, 0, -1)
}
var lastKey []byte = nil
var n int64 = 0
for ; it.Valid(); it.Next() {
n++
lastKey = it.Key()
}
it.Close()
if _, m, _, err := db.zDecodeScoreKey(lastKey); err == nil && bytes.Equal(m, member) {
n--
return n, nil
}
}
}
return -1, nil
}