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package main
import (
"encoding/binary"
"io"
)
type MessageType byte
type BlockPayload struct {
Index uint32
Begin uint32
Block []byte
}
type IncomingMessage struct {
Len uint32
MessageType MessageType
Payload []byte
}
type OutgoingMessage struct {
MessageType MessageType
Writer io.Writer
}
type RequestPayload struct {
Index uint32
Begin uint32
Length uint32
}
const (
MessageTypeChoke MessageType = iota
MessageTypeUnchoke
MessageTypeInterested
MessageTypeNotInterested
MessageTypeHave
MessageTypeBitfield
MessageTypeRequest
MessageTypePiece
MessageTypeCancel
)
func (o *OutgoingMessage) Write(b []byte) (int, error) {
msgLen := 1 + len(b)
payloadBuff := make([]byte, msgLen+4)
binary.BigEndian.PutUint32(payloadBuff[0:4], uint32(msgLen))
payloadBuff[4] = byte(o.MessageType)
if msgLen > 1 {
copy(payloadBuff[5:], b)
}
return o.Writer.Write(payloadBuff)
}
func (r RequestPayload) Bytes() []byte {
buf := make([]byte, 12)
binary.BigEndian.PutUint32(buf[0:4], r.Index)
binary.BigEndian.PutUint32(buf[4:8], r.Begin)
binary.BigEndian.PutUint32(buf[8:12], r.Length)
return buf
}
func (p *BlockPayload) Write(b []byte) (int, error) {
p.Index = binary.BigEndian.Uint32(b[0:4])
p.Begin = binary.BigEndian.Uint32(b[4:8])
p.Block = b[8:]
return len(b), nil
}
func (p *BlockPayload) WriteTo(w io.Writer) (int64, error) {
n, err := w.Write(p.Block)
return int64(n), err
}
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