zfit: Compression for FIT files

Contains a delta encoder / decoder and heatshrink compression.

heatshrink comes from https://github.com/atomicobject/heatshrink

To build

Type make, which builds both static and dynamically-allocated compressor / decompressors.

To use on desktop

Start with the dynamic/fit_*zip.c files.

The fit_zip executable can take two command-line arguments: -w sets the window size and -l sets the lookup size. -w 0 has a special meaning: No compression is performed, just delta encoding.

The fit_unzip executable can take one command-line flag: -d disables decompression and performs only delta decoding.

To use embedded

Start with static/fit_zip.c. You will need to supply FILE * file descriptors to read and write. Only fread() and fwrite() are called on these, so they can be search-and-replaced to a different type of file descriptors if necessary. (or maybe macro-ized?)

See zfit.pdf to choose appropriate parameters for your device.

File descriptions

File	Description
./README	This file
./LICENSE	ISC License, like heatshrink itself
./zfit.pdf	Algorithm documentation
./Makefile	Makes both static and dynamic variants
./heatshrink	git pull of heatshrink source
./static	Statically-allocated variant. Encoder only.
./dynamic	Dynamically-allocated, encoder and decoder
./static/heatshrink_config.h	heatshrink configuration for static alloc
./static/fit_zip.c	Source for static compressor
./static/Makefile	Builds static compressor
./verify.py	Python helper for verification / testing
./dynamic/heatshrink_config.h	heatshrink configuration for dynamic alloc
./dynamic/fit_zip.c	Source for dynamic compressor
./dynamic/fit_unzip.c	Source for dynamic decompressor
./dynamic/Makefile	Builds dynamic compressor / decompressor
./fit_delta_encode.c	FIT delta encoder