zig-systems-software

A collection of small, self-contained Zig projects — systems programming experiments written to explore the language rather than to ship a product. Each directory is an independent zig build project with its own build.zig and build.zig.zon; there is no workspace-level build.

Themes that recur: comptime-driven parsing, allocator design, C interop, WebAssembly targets, and cryptography.

Projects

Project	What it is
mkvify	Batch video → MKV converter for smart-TV playback. Probes files through the FFmpeg C libraries (libavformat/libavcodec) instead of shelling out to ffprobe.
aead-encryption	Authenticated file encryption with ChaCha20-Poly1305. PBKDF2-HMAC-SHA256 key derivation, chunked format with a per-chunk nonce and Poly1305 tag.
csv-validator	Schema-driven CSV validator compiled to WebAssembly, with a browser front-end that runs validation entirely client-side.
json-parser	Comptime JSON parser — JsonParser(T) generates a parser for the target type, so the shape of T drives the parse.
toon-parser	The same comptime approach applied to an indentation-sensitive format.
bump-allocator	Thread-safe bump/arena allocator over a fixed buffer. O(1) allocation, no individual free, bulk reclaim via reset().
xor-encryption	XOR cipher CLI. Educational — trivially broken by frequency analysis, and labelled as such.

Building

Each project stands alone:

cd <project>
zig build                      # build
zig build test --summary all   # run its tests
zig build -Doptimize=ReleaseFast

csv-validator targets WebAssembly and is driven from index.html:

cd csv-validator
zig build -Dtarget=wasm32-freestanding -Doptimize=ReleaseSmall
python3 -m http.server        # then open index.html

mkvify is the one project with an external dependency — it links the FFmpeg C libraries and needs their development headers:

sudo pacman -S ffmpeg                       # Arch
sudo apt install ffmpeg libavformat-dev libavcodec-dev libavutil-dev

Zig version

Everything targets Zig 0.16, but each build.zig.zon pins a different 0.16.0-dev nightly, so behaviour varies against the 0.16.0 release. Current state on stable 0.16.0:

Project	0.16.0 release
aead-encryption	builds
bump-allocator	builds
csv-validator	builds
json-parser	builds
mkvify	builds
toon-parser	library-shaped; build.zig still builds an executable and no main exists
xor-encryption	uses std.heap.GeneralPurposeAllocator, renamed to DebugAllocator

Zig 0.16 moved a lot of std around. The renames that account for most breakage in older code here:

Older	0.16
pub fn main() !void	pub fn main(init: std.process.Init) !void
std.fs.File	std.Io.File
std.heap.GeneralPurposeAllocator	std.heap.DebugAllocator
std.process.argsAlloc	init.minimal.args.toSlice(arena)
Child.init / spawnAndWait	std.process.spawn(io, .{ .argv = ... })
Dir.makePath / Dir.realpath	Dir.createDirPath / Dir.realPath
std.ArrayList (managed)	unmanaged: .empty, append(alloc, x)

Layout

<project>/
  build.zig
  build.zig.zon
  src/
    main.zig      entry point (or the exported surface, for library-shaped projects)
    root.zig      module root where one is used

Notes

Tests live beside the code in test blocks and run with zig build test. mkvify carries the most (12), because its decision logic is deliberately kept free of C and I/O so the rules can be tested without a media file on disk — a pattern worth reusing anywhere a thin C layer wraps real logic.