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 := count // count may be very large, so we must limit it for below mem make. if nv <= 0 || nv > 1024 { nv = 64 } v := make([]ScorePair, 0, nv) var it *store.RangeLimitIterator //if reverse and offset is 0, count < 0, we may use forward iterator then reverse //because store 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 }