packet

package
v0.0.0-...-7a19e20 Latest Latest
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 Go to latest Published: Apr 25, 2024 License: BSD-3-Clause Imports: 5 Imported by: 5

Documentation

Index

Constants

View Source 
const (
	Alignment = 8

	// Packet header
	OffsetSize   = 0
	OffsetCode   = 4
	OffsetDomain = 6
	OffsetIndex  = 7
	HeaderSize   = 8

	// Services packet header
	OffsetServicesCount = HeaderSize + 0
	ServicesHeaderSize  = HeaderSize + 2

	// Flow packet header
	FlowHeaderSize = HeaderSize

	// Data packet header
	OffsetDataID   = HeaderSize + 0
	OffsetDataNote = HeaderSize + 4
	DataHeaderSize = HeaderSize + 8
)

Variables

This section is empty.

Functions

func Align 

func Align(length int) int

Align packet length up to a multiple of packet alignment.

func IsValidCall 

func IsValidCall(b []byte, c Code) bool

IsValidCall checks service call packet's or call result packet's header. Packet content is disregarded.

func IsValidData 

func IsValidData(b []byte, c Code) bool

IsValidData checks stream data packet's header. Data is disregarded.

func IsValidFlow 

func IsValidFlow(b []byte, c Code) bool

IsValidFlow checks stream flow packet, including the flow entries.

func IsValidInfo 

func IsValidInfo(b []byte, c Code) bool

IsValidInfo checks service info packet's header. Packet content is disregarded.

Types

type Buf 

type Buf []byte

Buf holds a packet of at least HeaderSize bytes.

func ImportCall 

func ImportCall(b []byte, c Code) (Buf, error)

ImportCall packet, validating it leniently. The buffer is NOT copied.

func Make 

func Make(code Code, domain Domain, packetSize int) Buf

func MakeCall 

func MakeCall(code Code, contentSize int) Buf

func MakeDataEOF 

func MakeDataEOF(code Code, id int32) Buf

func MakeFlow 

func MakeFlow(code Code, id, value int32) Buf

func MakeFlowEOF 

func MakeFlowEOF(code Code, id int32) Buf

func MakeInfo 

func MakeInfo(code Code, contentSize int) Buf

func MustBeCall 

func MustBeCall(b Buf) Buf

MustBeCall panicks if b is not in the call domain. The value is passed through.

func MustBeInfo 

func MustBeInfo(b Buf) Buf

MustBeInfo panicks if b is not in the info domain. The value is passed through.

func (Buf) Code 

func (b Buf) Code() Code

func (Buf) Content 

func (b Buf) Content() []byte

Content of a received packet, or buffer for initializing sent packet.

func (Buf) Cut 

func (b Buf) Cut(headerSize, prefixLen int) (prefix, unused Buf)

Cut a packet into two parts. The headerSize parameter determins how many bytes are initialized in the second part: the header is copied from the first part. The length of the first part is given as the prefixLen parameter. If the buffer is too short for the second part, the length of the second buffer will be zero.

func (Buf) Domain 

func (b Buf) Domain() Domain

func (Buf) EncodedSize 

func (b Buf) EncodedSize() int

EncodedSize decodes the packet header field.

func (Buf) Index 

func (b Buf) Index() uint8

func (Buf) SetCode 

func (b Buf) SetCode(code Code)

func (Buf) SetIndex 

func (b Buf) SetIndex(i uint8)

func (Buf) SetSize 

func (b Buf) SetSize()

SetSize encodes the current slice length into the packet header.

func (Buf) String 

func (b Buf) String() string

func (Buf) Thunk 

func (b Buf) Thunk() Thunk

Thunk returns a function which returns the packet.

type Code 

type Code int16

Code represents the source or destination of a packet. It is specific to a program instance. 

const (
	CodeServices Code = -1
)

func (Code) String 

func (code Code) String() string

type DataBuf 

type DataBuf Buf

DataBuf holds a data packet of at least DataHeaderSize bytes.

func ImportData 

func ImportData(b []byte, c Code) (DataBuf, error)

ImportData packet, validating it leniently. The buffer is NOT copied.

func MakeData 

func MakeData(code Code, id int32, dataSize int) DataBuf

func MustBeData 

func MustBeData(b Buf) DataBuf

MustBeData panicks if b is not in the data domain. The value is passed through.

func (DataBuf) Code 

func (b DataBuf) Code() Code

func (DataBuf) Cut 

func (b DataBuf) Cut(dataLen int) (prefix Buf, unused DataBuf)

func (DataBuf) Data 

func (b DataBuf) Data() []byte

func (DataBuf) DataLen 

func (b DataBuf) DataLen() int

func (DataBuf) EOF 

func (b DataBuf) EOF() bool

func (DataBuf) ID 

func (b DataBuf) ID() int32

func (DataBuf) Note 

func (b DataBuf) Note() int32

Note is a value associated with a data packet. Each service interface specifies its semantics separately.

func (DataBuf) SetNote 

func (b DataBuf) SetNote(value int32)

SetNote value. It defaults to zero.

func (DataBuf) String 

func (b DataBuf) String() string

func (DataBuf) Thunk 

func (b DataBuf) Thunk() Thunk

Thunk returns a function which returns the packet.

type Domain 

type Domain uint8
const (
	DomainCall Domain = iota
	DomainInfo
	DomainFlow
	DomainData
)

func (Domain) String 

func (dom Domain) String() string

type Flow 

type Flow struct {
	ID    int32 // Stream ID.
	Value int32 // Positive increment, EOF indicator (0), or negative note.
}

Flow change of a stream.

func (Flow) Increment 

func (f Flow) Increment() (n int32, ok bool)

Increment is positive (if ok).

func (Flow) IsEOF 

func (f Flow) IsEOF() bool

func (Flow) IsIncrement 

func (f Flow) IsIncrement() bool

func (Flow) IsNote 

func (f Flow) IsNote() bool

func (Flow) Note 

func (f Flow) Note() (n int32, ok bool)

Note is negative (if ok).

type FlowBuf 

type FlowBuf Buf

FlowBuf holds a flow packet of at least FlowHeaderSize bytes.

func MakeFlows 

func MakeFlows(code Code, count int) FlowBuf

func MustBeFlow 

func MustBeFlow(b Buf) FlowBuf

MustBeFlow panicks if b is not in the flow domain. The value is passed through.

func (FlowBuf) At 

func (b FlowBuf) At(i int) Flow

func (FlowBuf) Code 

func (b FlowBuf) Code() Code

func (FlowBuf) Len 

func (b FlowBuf) Len() int

func (FlowBuf) Set 

func (b FlowBuf) Set(i int, f Flow)

func (FlowBuf) SetFlow 

func (b FlowBuf) SetFlow(i int, id, value int32)

func (FlowBuf) String 

func (b FlowBuf) String() string

func (FlowBuf) Thunk 

func (b FlowBuf) Thunk() Thunk

Thunk returns a function which returns the packet.

type Service 

type Service struct {
	MaxSendSize int // Maximum size which the program is prepared to receive.
	Code        Code
}

Service packet properties.

type Thunk 

type Thunk func() (Buf, error)

Thunk may be called once to acquire a packet. It returns an empty buffer if no packet was available after all.

Source Files

View all Source files

Directories

Path Synopsis
Package packetio provides streaming utilities.
 Package packetio provides streaming utilities.

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