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 // TODO: Is that before or after the message?
22 func (d *Decoder) Decode(msg *Message) (err error) {
24 err = binary.Read(d.R, binary.BigEndian, &length)
27 err = fmt.Errorf("error reading message length: %s", err)
31 if length > d.MaxLength {
32 return errors.New("message too long")
39 r := &io.LimitedReader{R: d.R, N: int64(length)}
40 // Check that all of r was utilized.
46 err = fmt.Errorf("%d bytes unused in message type %d", r.N, msg.Type)
54 msg.Type = MessageType(c)
56 case Choke, Unchoke, Interested, NotInterested, HaveAll, HaveNone:
58 case Have, AllowedFast, Suggest:
59 err = msg.Index.Read(r)
60 case Request, Cancel, Reject:
61 for _, data := range []*Integer{&msg.Index, &msg.Begin, &msg.Length} {
68 b := make([]byte, length-1)
69 _, err = io.ReadFull(r, b)
70 msg.Bitfield = unmarshalBitfield(b)
72 for _, pi := range []*Integer{&msg.Index, &msg.Begin} {
79 msg.Piece = (*d.Pool.Get().(*[]byte))
80 if int64(cap(msg.Piece)) < dataLen {
81 return errors.New("piece data longer than expected")
83 msg.Piece = msg.Piece[:dataLen]
84 _, err := io.ReadFull(r, msg.Piece)
86 return errors.Wrap(err, "reading piece data")
94 msg.ExtendedID = ExtensionNumber(b)
95 msg.ExtendedPayload, err = ioutil.ReadAll(r)
97 err = binary.Read(r, binary.BigEndian, &msg.Port)
99 err = fmt.Errorf("unknown message type %#v", c)
104 func readByte(r io.Reader) (b byte, err error) {
106 n, err := r.Read(arr[:])
118 func unmarshalBitfield(b []byte) (bf []bool) {
119 for _, c := range b {
120 for i := 7; i >= 0; i-- {
121 bf = append(bf, (c>>uint(i))&1 == 1)