codacy-badger/arithmetic-coding

:wrench: Arithmetic coding algorithm implemented in Node.js, both API and CLI support. 算数编码 npm 包，支持 API 调用和 CLI。

arithmetic-coding

• English Documentation
• Chinese Documentation

Installation

Install as module for API usage:

npm i arithmetic-coding

Or install as global CLI:

npm i -g arithmetic-coding

API

From file path:

const ariCoding = require('arithmetic-coding');
// Encode from file
ariCoding.encode(__dirname + '/txt/long.txt', __dirname + '/txt/long-encoded.txt');
// Decode from file
ariCoding.decode(__dirname + '/txt/long-encoded.txt', __dirname + '/txt/long-decoded.txt');

From Buffer:

let data = Buffer.from('Example data', 'utf8');
// Encode from Buffer
let encoded = encode.encodeFromBuffer(data);
console.log(`encoded = ${encoded}`);
// Decode from Buffer
let decoded = decode.decodeFromBuffer(encoded);
console.log(`decoded = ${decoded}`);

Command-line interface

$ ari-coding -h
Usage: index [options] [command]

Options:
  -v, --version              output the version number
  -h, --help                 output usage information

Commands:
  encode|e [options] <file>  encode a file
  decode|d [options] <file>  decode a file

$ ari-coding encode -h
Usage: encode|e [options] <file>

encode a file

Options:
  -o, --output <file>  output file path
  -h, --help           output usage information

Performance

You can see the latest travis test for running time used by each test.

Some benchmarks are shown below:

File size (Bytes)	total time	encode time	decode time
60640	110ms	small	110ms
2130640	2940ms	426ms	2514ms

About the algorithm

1. Wikipedia
2. How to implement practical encoder/decoder
3. Reference-arithmetic-coding on GitHub