This crate provides support for compressing files using Sega's CMP run-length encoding scheme, which was used in games for the Sega Saturn game console.
Run-length encoding is a simple kind of compression which works by analyzing data for repetitive sequences of data (or "runs"); any repeating sequences can be replaced by commands to repeat X data N times.
For example, imagine the text AAAAAAAABBBBAABA.
If you described it in terms of patterns, you could think of it as being
8A4B2A1B1A - which takes up 10 bytes instead of 16.
Sega included CMP in the official Saturn SDK; they provided a closed-source commandline tool to compress data and source code to do compression from within games. As a result, many games used it for data with lots of repetitive content such as text and graphics. This crate's CMP implementation aims to be 100% compatible with the original decoder; it produces identical compressed data to the original encoder. Its output has been tested to work in commercial Saturn games which use CMP.
This crate provides two basic functions: the header-generating create_header,
and the data-creating compress. Most Saturn games store both in the same place,
with the header followed immedaitely by the compressed data.