Reference arithmetic coding

This project is a clear implementation of arithmetic coding, suitable as a reference for educational purposes. It is provided separately in Java, Python, C++, and is open source.

The code can be used for study, and as a solid basis for modification and extension. Consequently, the codebase optimizes for readability and avoids fancy logic, and does not target the best speed/memory/performance.

Home page with detailed description: https://www.nayuki.io/page/reference-arithmetic-coding

License

Copyright © 2026 Project Nayuki. (MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

• The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

• The Software is provided "as is", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the Software or the use or other dealings in the Software.