Exemplo n.º 1
0
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
}
Exemplo n.º 2
0
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
}