FileFS

FileFS: Implement a virtual file system within a single file.

Layout

.
├── bench/      # Cross-language full-API benchmark harness + matrix
├── c/          # C implementation (original)
├── cpp/        # Pure C++20 port
├── dotnet/     # Pure C# / .NET port
├── go/         # Pure-Go port
├── java/       # Pure Java 21 port
├── kotlin/     # Pure Kotlin/JVM port
├── lua/        # Pure Lua 5.4 port
├── moonbit/    # Pure MoonBit port
├── nodejs/     # Pure JavaScript ESM port
├── python/     # Python package (CPython bindings to c/)
├── rust/       # Pure-Rust port
├── swift/      # Pure Swift port
├── wasm/       # WebAssembly (Zig) + JS glue (in-memory image)
├── zig/        # Pure-Zig port
├── LICENSE
└── README.md

C

cd c
make
./demo

Includes FileGit (git-like VCS at /.git) and FileXfer (host ↔ FileFS binary import/export, including directory trees). See c/README.md.

cd c && make test

See c/README.md.

C++

cmake -S cpp -B cpp/build -DCMAKE_BUILD_TYPE=Release
cmake --build cpp/build -j
ctest --test-dir cpp/build --output-on-failure

See cpp/README.md.

.NET

cd dotnet
dotnet test

See dotnet/README.md.

Go

cd go
go build -o demo ./cmd/demo
./demo

See go/README.md.

Java

mvn -f java/pom.xml test

See java/README.md.

Kotlin

cd kotlin
./build.sh

See kotlin/README.md.

Lua

cd lua
lua5.4 tests/run_tests.lua

See lua/README.md.

MoonBit

cd moonbit
moon test

See moonbit/README.md.

Node.js

cd nodejs
npm test

See nodejs/README.md.

Python

cd python
python3 -m venv .venv
source .venv/bin/activate
pip install -e .
python -m unittest discover -s tests -v

See python/README.md.

Rust

cd rust
cargo test

See rust/README.md.

Swift

cd swift
swift test

See swift/README.md.

WebAssembly

cd wasm
zig build
npm test

In-memory FileFS image for browser/Node via Zig wasm32-freestanding + JS glue.
See wasm/README.md.

Zig

cd zig
zig build test

See zig/README.md.

Host language ports share the same on-disk format (512-byte blocks, magic 78 11 45 14).
The Wasm port uses the same block layout in an in-memory image suitable for browsers.

Performance matrix

Cross-language full-API microbenchmarks (ns/op, lower is better). Workload: filefs-full-api · iterations=20 · payload=4096 bytes. Cell colors are row-relative (green = faster for that API among measured ports, red = slower).

API \ Lang	c	cpp	dotnet	go	java	kotlin	lua	moonbit	nodejs	python	rust	swift	wasm	zig
mkfs	193.6µs	191.3µs	256.0µs	191.1µs	550.7µs	580.1µs	97.5µs	61.5µs	216.2µs	442.0µs	204.2µs	214.1µs	1.5µs	194.2µs
mount+umount	3.0µs	3.2µs	7.7µs	5.0µs	34.4µs	53.4µs	93.0µs	31.5µs	12.1µs	5.7µs	3.0µs	15.7µs	735ns	4.4µs
mkdir	333.9µs	885.3µs	657.0µs	399.9µs	790.6µs	608.4µs	50.33ms	1.49ms	615.7µs	797.0µs	421.0µs	302.7µs	3.4µs	410.9µs
chdir+getcwd	1.1µs	1.0µs	2.6µs	1.9µs	11.0µs	7.0µs	2.0µs	4.4µs	25.5µs	1.4µs	1.1µs	4.3µs	4.0µs	4.7µs
open(w)+close	258.7µs	349.8µs	544.2µs	334.1µs	687.8µs	591.0µs	92.61ms	1.29ms	572.4µs	245.8µs	329.6µs	236.4µs	3.5µs	323.6µs
write 4KiB	606.4µs	787.8µs	1.14ms	856.8µs	1.40ms	1.44ms	326.56ms	7.33ms	1.50ms	549.4µs	826.7µs	524.1µs	4.0µs	1.12ms
read 4KiB	3.2µs	3.3µs	4.2µs	10.1µs	17.6µs	6.1µs	80.0µs	12.0µs	29.0µs	3.7µs	6.8µs	15.6µs	3.2µs	10.7µs
seek+tell+rewind	2.9µs	3.0µs	7.0µs	9.2µs	16.3µs	5.4µs	2.0µs	2.9µs	49.4µs	3.4µs	14.6µs	29.6µs	3.4µs	6.3µs
copy_file	578.3µs	1.00ms	1.42ms	965.9µs	1.26ms	1.23ms	376.95ms	7.66ms	2.26ms	557.5µs	926.7µs	723.5µs	8.1µs	736.3µs
rename	25.5µs	1.24ms	1.38ms	1.05ms	1.84ms	1.91ms	603.29ms	5.11ms	1.90ms	714.6µs	1.68ms	871.0µs	11.4µs	965.9µs
remove_file	258.4µs	844.4µs	843.2µs	896.5µs	1.14ms	1.18ms	403.27ms	3.40ms	1.33ms	499.2µs	1.33ms	597.7µs	6.8µs	637.1µs
opendir+readdir	1.9µs	1.7µs	4.5µs	3.3µs	11.5µs	14.5µs	13.0µs	20.2µs	26.1µs	15.4µs	3.6µs	7.1µs	22.3µs	3.8µs
file/dir exists	2.6µs	2.6µs	3.2µs	5.1µs	10.0µs	1.6µs	2.0µs	1.9µs	19.9µs	4.2µs	2.7µs	10.8µs	23.5µs	3.0µs
begin+write+commit	244.2µs	420.7µs	574.8µs	547.4µs	632.3µs	817.1µs	329.10ms	3.10ms	811.8µs	408.6µs	449.6µs	382.4µs	6.4µs	357.2µs

Source SVG

bench/matrix.svg

Regenerate:

python3 bench/run_all.py

Raw results: bench/results/latest.json · unix=1784876936. Harness details: bench/README.md.