frame

Documentation

Index

• Constants
• type Frame
  • func From(header []byte, payload []byte) *Frame
  • func NewFrame() *Frame
  • func ReadFrame(data []byte) *Frame
  • func ReadHeader(data []byte) *Frame
  • func (*Frame) AppendOptions(header *[]byte, options []byte)
  • func (f *Frame) Bytes() []byte
  • func (f *Frame) Header() []byte
  • func (f *Frame) HeaderPtr() *[]byte
  • func (f *Frame) Payload() []byte
  • func (f *Frame) ReadFlags() byte
  • func (*Frame) ReadHL(header []byte) byte
  • func (f *Frame) ReadOptions(header []byte) []uint32
  • func (*Frame) ReadPayloadLen(header []byte) uint32
  • func (*Frame) ReadVersion(header []byte) byte
  • func (f *Frame) Reset()
  • func (*Frame) VerifyCRC(header []byte) bool
  • func (*Frame) WriteCRC(header []byte)
  • func (*Frame) WriteFlags(header []byte, flags ...byte)
  • func (f *Frame) WriteOptions(header *[]byte, options ...uint32)
  • func (f *Frame) WritePayload(data []byte)
  • func (*Frame) WritePayloadLen(header []byte, payloadLen uint32)
  • func (*Frame) WriteVersion(header []byte, version Version)
• type Version

Constants

const (
	CONTROL       byte = 0x01
	CODEC_RAW     byte = 0x04 //nolint:stylecheck,golint
	CODEC_JSON    byte = 0x08 //nolint:stylecheck,golint
	CODEC_MSGPACK byte = 0x10 //nolint:stylecheck,golint
	CODEC_GOB     byte = 0x20 //nolint:stylecheck,golint
	ERROR         byte = 0x40 //nolint:stylecheck,golint
	CODEC_PROTO   byte = 0x80 //nolint:stylecheck,golint
)

BYTE flags, it means, that we can set multiply flags from this group using bitwise OR For example CONTEXT_SEPARATOR | CODEC_RAW

const (
	RESERVED2 byte = 0x81
	RESERVED3 byte = 0x82
	RESERVED4 byte = 0x83
	RESERVED5 byte = 0x84
)

COMPLEX flags can't be used with Byte flags, because it's value more than 128

const OptionsMaxSize = 40

OptionsMaxSize represents header's options maximum size

const WORD = 4

WORD represents 32bit word

Types

type Frame

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

Frame defines new user level package format.

func From

func From(header []byte, payload []byte) *Frame

From will represent header and payload as a Frame

func NewFrame

func NewFrame() *Frame

NewFrame initializes new frame with 12-byte header and 100-byte reserved space for the payload

func ReadFrame

func ReadFrame(data []byte) *Frame

ReadFrame produces Frame from the RAW bytes first 12 bytes will be a header the rest - payload

func ReadHeader

func ReadHeader(data []byte) *Frame

ReadHeader reads only header, without payload

func (*Frame) AppendOptions

func (*Frame) AppendOptions(header *[]byte, options []byte)

AppendOptions appends options to the header

func (*Frame) Bytes

func (f *Frame) Bytes() []byte

Bytes returns header with payload

func (*Frame) Header

func (f *Frame) Header() []byte

Header returns frame header

func (*Frame) HeaderPtr

func (f *Frame) HeaderPtr() *[]byte

HeaderPtr returns frame header pointer

func (*Frame) Payload

func (f *Frame) Payload() []byte

Payload returns frame payload without header

func (*Frame) ReadFlags

func (f *Frame) ReadFlags() byte

ReadFlags Flags is full 1st byte

func (*Frame) ReadHL

func (*Frame) ReadHL(header []byte) byte

ReadHL The lower 4 bits of the 0th octet occupies our header len data. We should erase upper 4 bits, which contain information about Version To erase, we are applying bitwise AND to the upper 4 bits and returning result

func (*Frame) ReadOptions

func (f *Frame) ReadOptions(header []byte) []uint32

ReadOptions f.readHL() - 2 needed to know actual options size we know, that 2 WORDS is minimal header len extra WORDS will add extra 32bits to the options (4 bytes) cannot inline, cost 117 vs 80

func (*Frame) ReadPayloadLen

func (*Frame) ReadPayloadLen(header []byte) uint32

ReadPayloadLen LE format used to write Payload Using 4 bytes (2,3,4,5 bytes in the header)

func (*Frame) ReadVersion

func (*Frame) ReadVersion(header []byte) byte

ReadVersion ... To read version, we should return our 4 upper bits to their original place 1111_0000 -> 0000_1111 (15)

func (*Frame) Reset

func (f *Frame) Reset()

Reset a frame

func (*Frame) VerifyCRC

func (*Frame) VerifyCRC(header []byte) bool

VerifyCRC ... Reading info from 6th byte and verifying it with calculated in-place. Should be equal. If not - drop the frame as incorrect.

func (*Frame) WriteCRC

func (*Frame) WriteCRC(header []byte)

WriteCRC will calculate and write CRC32 4-bytes it to the 6th byte (7th reserved)

func (*Frame) WriteFlags

func (*Frame) WriteFlags(header []byte, flags ...byte)

func (*Frame) WriteOptions

func (f *Frame) WriteOptions(header *[]byte, options ...uint32)

WriteOptions Options slice len should not be more than 10 (40 bytes) we need a pointer to the header because we are reallocating the slice

func (*Frame) WritePayload

func (f *Frame) WritePayload(data []byte)

WritePayload writes payload

func (*Frame) WritePayloadLen

func (*Frame) WritePayloadLen(header []byte, payloadLen uint32)

WritePayloadLen LE format used to write Payload Using 4 bytes (2,3,4,5 bytes in the header)

func (*Frame) WriteVersion

func (*Frame) WriteVersion(header []byte, version Version)

WriteVersion To write version, we should do the following: 1. For example, we have version 15 it's 0000_1111 (1 byte) 2. We should shift 4 lower bits to upper and write that to the 0th byte 3. The 0th byte should become 1111_0000, but it's not 240, it's only 15, because version only 4 bits len

type Version

type Version byte

const (
	VERSION_1 Version = 0x01 //nolint:stylecheck,golint
)