Move Go code to src/

src/go-agentx/pdu/header.go

@@ -0,0 +1,61 @@
+// Copyright 2018 The agentx authors
+// Licensed under the LGPLv3 with static-linking exception.
+// See LICENCE file for details.
+
+package pdu
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+)
+
+const (
+	// HeaderSize defines the total size of a header packet.
+	HeaderSize = 20
+)
+
+// Header defines a pdu packet header
+type Header struct {
+	Version       byte
+	Type          Type
+	Flags         Flags
+	SessionID     uint32
+	TransactionID uint32
+	PacketID      uint32
+	PayloadLength uint32
+}
+
+// MarshalBinary returns the pdu header as a slice of bytes.
+func (h *Header) MarshalBinary() ([]byte, error) {
+	buffer := bytes.NewBuffer([]byte{h.Version, byte(h.Type), byte(h.Flags), 0x00})
+
+	binary.Write(buffer, binary.LittleEndian, h.SessionID)
+	binary.Write(buffer, binary.LittleEndian, h.TransactionID)
+	binary.Write(buffer, binary.LittleEndian, h.PacketID)
+	binary.Write(buffer, binary.LittleEndian, h.PayloadLength)
+
+	return buffer.Bytes(), nil
+}
+
+// UnmarshalBinary sets the header structure from the provided slice of bytes.
+func (h *Header) UnmarshalBinary(data []byte) error {
+	if len(data) < HeaderSize {
+		return fmt.Errorf("not enough bytes (%d) to unmarshal the header (%d)", len(data), HeaderSize)
+	}
+
+	h.Version, h.Type, h.Flags = data[0], Type(data[1]), Flags(data[2])
+
+	buffer := bytes.NewBuffer(data[4:])
+
+	binary.Read(buffer, binary.LittleEndian, &h.SessionID)
+	binary.Read(buffer, binary.LittleEndian, &h.TransactionID)
+	binary.Read(buffer, binary.LittleEndian, &h.PacketID)
+	binary.Read(buffer, binary.LittleEndian, &h.PayloadLength)
+
+	return nil
+}
+
+func (h *Header) String() string {
+	return "(header " + h.Type.String() + ")"
+}