codec

Documentation

Overview

Package codec implements readers and writers for https://github.com/dominictarr/packet-stream-codec

Packet structure:

(
	[flags (1byte), length (4 bytes, UInt32BE), req (4 bytes, Int32BE)] # Header
	[body (length bytes)]
) *
[zeros (9 bytes)]

Flags:

[ignored (4 bits), stream (1 bit), end/err (1 bit), type (2 bits)]
type = {0 => Buffer, 1 => String, 2 => JSON} # PacketType

Index

• type Body
  • func (b Body) String() string
• type Flag
  • func (f Flag) Clear(g Flag) Flag
  • func (f Flag) Get(g Flag) bool
  • func (f Flag) Set(g Flag) Flag
  • func (f Flag) String() string
• type Header
• type Packet
  • func ReadAllPackets(rd *Reader) ([]*Packet, error)
• type Reader
  • func NewReader(r io.Reader) *Reader
  • func (r Reader) NextBodyReader(pktLen uint32) io.Reader
  • func (r Reader) ReadBodyInto(w io.Writer, pktLen uint32) error
  • func (r Reader) ReadHeader(hdr *Header) error
  • func (r Reader) ReadPacket() (*Packet, error)
• type Writer
  • func NewWriter(w io.Writer) *Writer
  • func (w *Writer) Close() error
  • func (w *Writer) WritePacket(r Packet) error

Types

type Body

type Body []byte

func (Body) String

func (b Body) String() string

type Flag

type Flag byte

Flag is the first byte of the Header

const (
	FlagString Flag = 1 << iota // type
	FlagJSON                    // bits
	FlagEndErr
	FlagStream
)

Flag bitmasks

func (Flag) Clear

func (f Flag) Clear(g Flag) Flag

func (Flag) Get

func (f Flag) Get(g Flag) bool

func (Flag) Set

func (f Flag) Set(g Flag) Flag

func (Flag) String

func (f Flag) String() string

type Header

type Header struct {
	Flag Flag
	Len  uint32
	Req  int32
}

Header is the wire representation of a packet header

type Packet

type Packet struct {
	Flag Flag
	Req  int32
	Body Body
}

Packet is the decoded high-level representation

func ReadAllPackets

func ReadAllPackets(rd *Reader) ([]*Packet, error)

type Reader

type Reader struct {
	// contains filtered or unexported fields
}

func NewReader

func NewReader(r io.Reader) *Reader

func (Reader) NextBodyReader

func (r Reader) NextBodyReader(pktLen uint32) io.Reader

func (Reader) ReadBodyInto

func (r Reader) ReadBodyInto(w io.Writer, pktLen uint32) error

func (Reader) ReadHeader

func (r Reader) ReadHeader(hdr *Header) error

ReadHeader only reads the header packet data (flag, len, req id). Use the exposed io.Reader to read the body.

func (Reader) ReadPacket

func (r Reader) ReadPacket() (*Packet, error)

ReadPacket decodes the header from the underlying reader, and reads as many bytes as specified in it TODO: pass in packet pointer as arg to reduce allocations

type Writer

type Writer struct {
	// contains filtered or unexported fields
}

func NewWriter

func NewWriter(w io.Writer) *Writer

NewWriter creates a new packet-stream writer

func (*Writer) Close

func (w *Writer) Close() error

Close sends 9 zero bytes and also closes it's underlying writer if it is also an io.Closer

func (*Writer) WritePacket

func (w *Writer) WritePacket(r Packet) error

WritePacket creates an header for the Packet and writes it and the body to the underlying writer