codec

README

Codec

A go library to encode/decode data which integrates well with io.WriterTo and io.ReaderFrom interfaces.

Documentation

Overview

Package codec provides a simple interface for encoding and decoding data.

It is based around the io.ReaderFrom and io.WriterTo interfaces to allow for easy transfer of data between a source and destination using arbitrary encodings.

The encoding and decoding functions are implemented as io.Writer and io.Reader, respectively. In order to support a new encoding, you must implement the Encoder and Decoder interfaces, i.e., you must provide a way to create a new io.Writer and io.Reader for the encoding.

Example:

- Define an Encoder:

type myEncoder struct {
	w io.Writer
}

func (m *myEncoder) Write(p []byte) (n int, err error) {
	// In practice, you would transform the input data
	// before writing it to the underlying writer.
	return m.w.Write(p)
}

- Define a Decoder:

type myDecoder struct {
	r io.Reader
}

func (m *myDecoder) Read(p []byte) (n int, err error) {
	// Read at most len(p)
	data := make([]byte, len(p))
	n, err = m.r.Read(data)
	if err != nil {
		return n, err
	}
	// In practice, you would transform the input data
	// before writing it to the underlying writer.
	copy(p, data[:n])
	return n, nil
}

- Define an Encoding struct

type myEncoding struct{}

func (e *myEncoding) NewWriter(w io.Writer) (io.WriteCloser, error) {
	return &myEncoder{w}, nil
}

func (e *myEncoding) NewReader(r io.Reader) (io.ReadCloser, error) {
	return &myDecoder{r}, nil
}

// Verify that myEncoding implements the Encoding interface
var (
	_ Encoding  = &myEncoding{}
)

- Now you're good to go:

func doSomething(src io.WriterTo, dest io.ReaderFrom) {
	// Create a new encoding
	encoding := &myEncoding{}
	// You can encode data
	Encode(encoding, src, dest)
	// You can decode data
	Decode(encoding, src, dest)
}

Index

• func Decode(encoding Decoder, src io.WriterTo, dest io.ReaderFrom) (int64, error)
• func Encode(encoding Encoder, src io.WriterTo, dest io.ReaderFrom) (int64, error)
• type Decoder
• type Encoder
• type Encoding

Functions

func Decode

func Decode(encoding Decoder, src io.WriterTo, dest io.ReaderFrom) (int64, error)

Decode reads from src and write to dest after decoding using provided decoder.

func Encode

func Encode(encoding Encoder, src io.WriterTo, dest io.ReaderFrom) (int64, error)

Encode reads from src and write to dest after encoding using provided encoder.

Types

type Decoder

type Decoder interface {
	NewReader(r io.Reader) (io.Reader, error)
}

Decoder is an interface for decoding data.

type Encoder

type Encoder interface {
	NewWriter(w io.Writer) (io.Writer, error)
}

Encoder is an interface for encoding data.

type Encoding

type Encoding interface {
	Encoder
	Decoder
}

Encoding is an interface for encoding and decoding data.