Did you ever saw a char and thought: "Damn, 1 byte for a single char is pretty darn inefficient"? No? Well I did. So what I decided to do instead is to pack 5 chars, convert each char to a 2 digit integer and then concat those 5 2 digit ints together into one big unsigned int and boom, I saved 5 chars using only 4 instead of 5 bytes. The reason this works is, because one unsigned int is a ten digit long number and so I can save one char using 2 digits. In theory you could save 32 different chars using this technique (the first two digits of an unsigned int are 42 and if you dont want to account for a possible 0 in the beginning you end up with 32 chars). If you would decide to use all 10 digits you could save exactly 3 chars. Why should anyone do that? Idk. Is it way to much work to be useful? Yes. Was it funny? Yes.
Anyone whos interested in the code: Heres how I did it in C: https://pastebin.com/hDeHijX6
Yes I know, the code is probably bad, but I do not care. It was just a funny useless idea I had.
You would have done well with this kind of thinking in the mid-80s when you needed to fit code and data into maybe 16k!
As long as you were happy to rewrite it in Z80 or 6502.
Another alternative is arithmetic encoding. For instance, if you only needed to store A-Z and space, you code those as 0-26, then multiply each char by 1, 27, 27^2, 26^3 etc, the add them.
To unpack them, divide by 27 repeatedly, the remainder each time is each character. It's simply covering numbers to base-27.
It wouldn't make much difference from using 5 bits per char for a short run, though, but could be efficient for longer strings, or if encoding a smaller set of characters.
It sucks for me because my brain innately enjoys this kind of thinking
Play the Zachtronics programming games (Exapunks, Shenzen I/O, TIS-100) if you haven't yet.