11 "github.com/pkg/errors"
17 MaxLength Integer // TODO: Should this include the length header or not?
20 // io.EOF is returned if the source terminates cleanly on a message boundary.
21 func (d *Decoder) Decode(msg *Message) (err error) {
23 err = binary.Read(d.R, binary.BigEndian, &length)
26 err = fmt.Errorf("error reading message length: %w", err)
30 if length > d.MaxLength {
31 return errors.New("message too long")
38 r := &io.LimitedReader{R: d.R, N: int64(length)}
39 // Check that all of r was utilized.
45 err = fmt.Errorf("%d bytes unused in message type %d", r.N, msg.Type)
53 msg.Type = MessageType(c)
55 case Choke, Unchoke, Interested, NotInterested, HaveAll, HaveNone:
57 case Have, AllowedFast, Suggest:
58 err = msg.Index.Read(r)
59 case Request, Cancel, Reject:
60 for _, data := range []*Integer{&msg.Index, &msg.Begin, &msg.Length} {
67 b := make([]byte, length-1)
68 _, err = io.ReadFull(r, b)
69 msg.Bitfield = unmarshalBitfield(b)
71 for _, pi := range []*Integer{&msg.Index, &msg.Begin} {
78 msg.Piece = (*d.Pool.Get().(*[]byte))
79 if int64(cap(msg.Piece)) < dataLen {
80 return errors.New("piece data longer than expected")
82 msg.Piece = msg.Piece[:dataLen]
83 _, err := io.ReadFull(r, msg.Piece)
85 return errors.Wrap(err, "reading piece data")
93 msg.ExtendedID = ExtensionNumber(b)
94 msg.ExtendedPayload, err = ioutil.ReadAll(r)
96 err = binary.Read(r, binary.BigEndian, &msg.Port)
98 err = fmt.Errorf("unknown message type %#v", c)
103 func readByte(r io.Reader) (b byte, err error) {
105 n, err := r.Read(arr[:])
117 func unmarshalBitfield(b []byte) (bf []bool) {
118 for _, c := range b {
119 for i := 7; i >= 0; i-- {
120 bf = append(bf, (c>>uint(i))&1 == 1)