tiny-snake.rs

A very tiny terminal snake game, purely implemented in Rust.

Features

Optimized binary has only 2760 bytes.
No dependencies. Not even libc.
Works on x86_64 Linux 3.17+.
100% Rust 🦀.
Panic-free.

Background

While thinking about implementing the snake in the bf lang using only ANSI escape codes, I decided to build a proof of concept for the snake logic, and ANSI rendering.

I have also seen this blog post about writing a Hello World program using raw syscalls, and I figured out that is all I would need to write the snake game. I also took the opportunity to implement it in a single file, using rustc directly, and avoiding cargo boilerplate.

In the end, for my delight, I discovered that after building for release and stripping symbols, of the binary was less than 20 KiB. So I decided invest a little more in decreasing the binary size.

Changing some parameters parameters for compilation decrease the total size to about 7KiB, and after making the program panic-free the total size decreased to less than 3KiB.

There is still room for improvements, but the last change was so dramatic that I am now satisfied.

Building and Running

To build the game binary you only need rustc and make:

$ make snake

This creates a binary called snake in the current folder, and you can run it with:

$ ./snake

You can also build and run in a single command:

$ make run

The Makefile contains the following commands:

snake: build the main binary.
snake.debug: build the a version of the binary with debug info.
size: print informations about the size of each symbol and section, and total size of the binary.
snake.asm: emmit a clean up version of the assembly emmited by rustc.
gdb: run snake.debug on rust-gdb.
objdump: produce a clean up disassembly of snake.debug.
fmt: format snake.rs
clean: delete all generated files.

Acknowledgments

Kpcyrd's blog post about writing a Hello World program using only raw syscalls.
Graham King's blog post that lists many techniques for reducing the size of a Rust binary, although I still didn't use all of them.