Method LRange

tx_list.go:276–314

LRange returns the specified elements of the list stored in the bucket at given bucket,key, start and end. The offsets start and stop are zero-based indexes 0 being the first element of the list (the head of the list), 1 being the next element and so on. Start and end can also be negative numbers in

(bucket string, key []byte, start, end int)

// Start and end can also be negative numbers indicating offsets from the end of the list,
// where -1 is the last element of the list, -2 the penultimate element and so on.
func (tx *Tx) LRange(bucket string, key []byte, start, end int) ([][]byte, error) {
	if err := tx.checkTxIsClosed(); err != nil {
		return nil, err
	}

	b, err := tx.db.bucketMgr.GetBucket(DataStructureList, bucket)
	if err != nil {
		return nil, err
	}
	var (
		bucketId = b.Id
		l        *data.List
		exist    bool
	)

	if l, exist = tx.db.Index.List.exist(bucketId); !exist {
		return nil, ErrBucket
	}
	if tx.CheckExpire(bucket, key) {
		return nil, ErrListNotFound
	}

	records, err := l.LRange(string(key), start, end)
	if err != nil {
		return nil, err
	}

	values := make([][]byte, len(records))

	for i, r := range records {
		value, err := tx.db.getValueByRecord(r)
		if err != nil {
			return nil, err
		}
		values[i] = value
	}

	return values, nil
}

// LRem removes the first count occurrences of elements equal to value from the list stored in the bucket at given bucket,key,count.
// The count argument influences the operation in the following ways: