Method Decode

tsdb/compression/compression.go:112–130

Decode returns the decoded form of src or error, given expected compression type. The buf is used as a buffer for the returned decoded entry, and it must not overlap with src. It is valid to pass a nil buf.

(t Type, src, buf []byte)

// The buf is used as a buffer for the returned decoded entry, and it must not
// overlap with src. It is valid to pass a nil buf.
func (d *Decoder) Decode(t Type, src, buf []byte) (_ []byte, err error) {
	switch {
	case len(src) == 0, t == "", t == None:
		return src, nil
	case t == Snappy:
		// The snappy library uses `len` to calculate if we need a new buffer.
		// In order to allocate as few buffers as possible make the length
		// equal to the capacity.
		buf = buf[:cap(buf)]
		return snappy.Decode(buf, src)
	case t == Zstd:
		if d == nil {
			return nil, errors.New("zstd requested but Decoder was not initialized with NewDecoder()")
		}
		return d.r.DecodeAll(src, buf[:0])
	default:
		return nil, fmt.Errorf("unsupported compression type: %s", t)
	}
}