COBS

A Golang module for the Consistent Overhead Byte Stuffing (COBS) algorithm.

Usage

This module provides both simple helper functions to Encode/Decode []byte arrays and Encoder/Decoder structs to stream bytes to an io.Writer instance.

Encode/Decode functions

The helper functions will allocate buffers to hold the encoded/decoded data and return a []byte slice or an error.

The following example encodes a string with embedded zeroes:

package main

import (
	"os"

	"github.com/pdgendt/cobs"
)

func main() {
	enc, _ := cobs.Encode([]byte{'H', 'e', 'l', 'l', 'o', 0x00, 'w', 'o', 'r', 'l', 'd', '!'})

	os.Stdout.write(enc)
}

Encoder/Decoder structs

The structs require an io.Writer instance on creation. As soon as data is available it is written, for the Encoder this is done for each group, with a maximum of 255 bytes, for the Decoder every byte is written individually.

The structs implement the io.Writer interface to allow chaining.

The following example encodes bytes read from os.Stdin and writes them to os.Stdout:

package main

import (
	"io"
	"os"

	"github.com/pdgendt/cobs"
)

func main() {
	enc := cobs.NewEncoder(os.Stdout)

	if _, err := io.Copy(enc, os.Stdin); err != nil {
		panic(err)
	}

	// Close needs to be called to flush the last group
	if err := enc.Close(); err != nil {
		panic(err)
	}
}

CLI tools

The cmd/ directory contains simple encode/decode command line tools that take in data from stdin and writes it to stdout.

This can be used to pipe encoded/decoded data to other processes.

$ echo "Hello world" | go run cmd/encode/main.go | go run cmd/decode/main.go
Hello world