notebook VS AdventOfCode2019

Open source: End to End Encrypted Notebook / Website & Builder. Just had first release last week to fight for privacy and freedom of speech.

https://github.com/privapps/notebook

I've been (slowly) doing Advent of Code 2019 on an STM32F303 microcontroller. I want all of the problem data to be stored in the binary, with the answers being output on a display. Most of my time so far has been spent on getting the clock working, and compression/decompression. I only have limited space (256KB), and the 20 of last year's problems I solved take up 221KB, so I decided the best course of action would be to store them compressed when possible.

I did consider just using compression library, but decided against it partly because it would be more interesting to write it myself, but also having a quick look I couldn't find one that could do decompression without needing additional temporary storage. It's not that fancy, just LZW with a multi-stage compression to optimize the dictionary.

Because of how many of the inputs work, you can often handle it in smaller chunks (e.g. one line at a time, I called them records), so the inputs have a small amount of pre-processing on my PC to split them up into smaller chunks so the entire input doesn't need to be held in RAM at once.

Of course, not all input data will compress well, some will even "compress" to a larger size, so I've also abstracted over the data storage so that it can handle reading records from compressed or uncompressed inputs.

I've done 4 days so far, and none of the inputs have compressed. Total runtime is 3.24 seconds (that day 4...).

Current state can be found here for the morbidly curious: https://github.com/Measter/AdventOfCode2019 Spoilers are in the mcu/src/challenges folder.