A data compression/decompression library for embedded/real-time systems.

• Low memory usage (as low as 50 bytes)
  It is useful for some cases with less than 50 bytes, and useful for many general cases with < 300 bytes.
• Incremental, bounded CPU use
  You can chew on input data in arbitrarily tiny bites. This is a useful property in hard-realtime environments.
• Can use either static or dynamic memory allocation
  The library doesn't impose any constraints on memory management.
• BSD license
  You can use it freely, even for commercial purposes.

There is a standalone command-line program, heatshrink, but the encoder and decoder can also be used as libraries, independent of each other. To do so, copy heatshrink_common.h, heatshrink_config.h, and either heatshrink_encoder.c or heatshrink_decoder.c (and their respective header) into your project.

Dynamic allocation is used by default, but in an embedded context, you probably want to statically allocate the encoder/decoder. Set HEATSHRINK_DYNAMIC_ALLOC to 0 in heatshrink_config.h.

heatshrink is based on LZSS, since it's particularly suitable for compression in small amounts of memory. It can use an optional index to make compression faster, but otherwise can run in under 100 bytes of memory.

For more information, see the blog post for an overview, and the heatshrink_encoder.h / heatshrink_decoder.h header files for API documentation.