Heatshrink

Heatshrink is an open-source lossless data compression library designed for embedded and resource-constrained systems. It provides a small streaming compressor and decompressor that can operate on data as it arrives, making it suitable for sensor data, telemetry, and other real-time communications in microcontroller environments.

The library emphasizes a tiny memory footprint and portability. It is written in portable C and can run with limited RAM, with configuration options that adjust the internal lookback window and other memory-related parameters. The encoder and decoder operate on streaming data via small input and output buffers and maintain internal state between calls, allowing incremental processing without large buffers.

Heatshrink uses a compact coding scheme that combines literals with back-references to previously seen data. The streaming format supports incremental flushing and end-of-stream signaling, enabling integration with asynchronous data flows typical of embedded networks.

Applications include telemetry from sensors, industrial monitoring, and other IoT contexts where bandwidth is limited and devices have constrained processing power. The library is designed to be portable across compilers and architectures common in embedded development.

Heatshrink is available as an open-source project. The exact licensing terms are defined in its repository, and contributions are welcome from the community. See also data compression, LZ77, entropy coding, and embedded systems.