Merge pull request #68 from trifectatechfoundation/blogpost-zlib-stable-api

blog post on zlib 0.6

Author: erikjee

content/blog/zlib-rs stable API.md

@@ -0,0 +1,57 @@
++++
+title = "zlib-rs: a stable API and 30M downloads"
+slug = "zlib-rs-stable-api"
+authors = ["Folkert de Vries"]
+date = "2026-01-27"
+
+[taxonomies]
+tags = ["zlib-rs", "data compression"]
+
++++
+
+Since the first release in April 2024, zlib-rs has come a long way. It has seen major adoption over the last year, and, we're proud to say, is now feature complete.
+We've released zlib-rs 0.6, the first version with [a stable and complete API](https://docs.rs/zlib-rs/0.6.0/zlib_rs/).
+
+<!-- more -->
+
+With this milestone, we now fully deliver on the promise of our [Data compression initiative](/initiatives/data-compression): real alternatives to C/C++ counterparts that reduce attack surface through memory safety and provide on-par performance.
+
+Features and promises are nice, but seeing adoption grow is the cherry on the cake: zlib-rs recently crossed 30M downloads, 25M+ in the last year, and is on track to become the default implementation in `flate2`, which is expected to further boost usage.
+
+This blog post is a quick round-up of the latest release, 0.6. The full release notes are [here](https://github.com/trifectatechfoundation/zlib-rs/releases/tag/v0.6.0).
+
+## Stable API
+
+The `zlib-rs` crate now has a stable API. It hides away most of the internals, but exposes enough for `flate2` and `rustls`. Generally we recommend to use `zlib-rs` via `flate2` in applications, but for low-level libraries using `zlib-rs` directly is now an option.
+
+Additionally `flate2` now uses the `zlib-rs` CRC32 checksum implementation when `zlib-rs` is used. Our implementation is faster, and it saves a dependency.
+
+## C-compatible API
+
+The `libz-rs-sys` crate is a C-compatible API built on top of `zlib-rs`. It can be compiled into a drop-in compatible C library.
+
+### ABI changes
+
+All exported functions now use `extern "C"` instead of `extern "C-unwind"`.
+
+This is a change we've wanted to make for a while, but held off on because we had rust crates using `libz-rs-sys`. Now that they instead use `zlib-rs` directly, we can focus more on C users in the `libz-rs-sys` crate.
+
+Normally, when rust functions panic, they start unwinding the stack. That is only valid when the caller anticipates that the callee might unwind. For rust functions this case is handled, but when exporting a function, the caller is likely not written in rust, and does not support stack unwinding.
+
+If the callee does unwind into an unsuspecting caller, behavior is undefined. Although `libz-rs-sys` should not panic, causing UB when we somehow do is a massive footgun. So now we use `extern "C"`, which will instead abort the program at the FFI boundary.
+
+### Support for `gz*` functions
+
+We've added functions like `gzread`, `gzwrite` and many others to the `libz-rs-sys` API. These were already available in `libz-rs-sys-cdylib`, and have now been promoted. They are still behind the `gz` feature, so enable that if you need these functions. Most of the `gz*` functions were implemented by [@brian-pane](https://github.com/brian-pane).
+
+In addition, we've implemented several other missing functions (like `inflateBack`), so that we're now fully compatible with the zlib and zlib-ng public API.
+
+## Thank yous
+
+For completing this final milestone we thank all the contributors, specifically [@brian-pane](https://github.com/brian-pane), and the [Sovereign Tech Fund](https://www.sovereign.tech/) for investing in the API stabilization. 
+
+## What's next
+
+Although the public API is now complete, a project like this is never truly done. There are always new optimization ideas to try, versions to update, and obscure edge cases to support.
+
+The biggest remaining items is that technically the API is only complete when using nightly rust. The `gzprintf` and `gzvprintf` functions are c-variadic, and c-variadic function definitions are currently unstable. I hope to stabilize [`#[feature(c_variadic)]`](https://github.com/rust-lang/rust/issues/44930) in the next ~6 months.

content/initiatives/data-compression.md

@@ -31,6 +31,7 @@ supporters = [
 ]
 
 blogposts = [
+    "zlib-rs stable API",
     "Emulating avx-512 intrinsics in Miri",
     "bzip2 crate switches from C to 100% rust",
     "SIMD in zlib-rs (part 2): compare256",

content/news.md

@@ -5,6 +5,7 @@ template = "news.html"
 
 [extra]
 blogposts = [
+    "zlib-rs stable API",
     "Video: sudo-rs and beyond (Ubuntu Summit 25.10)",
     "Calling for memory safety incentives in EU cybersecurity policies",
     "Emulating avx-512 intrinsics in Miri",

content/projects/zlib-rs.md

@@ -28,6 +28,7 @@ supporters = [
 ]
 
 blogposts = [
+    "zlib-rs stable API",
     "Emulating avx-512 intrinsics in Miri",
     "SIMD in zlib-rs (part 2): compare256",
     "SIMD in zlib-rs (part 1): Autovectorization and target features",