C API

[hargoniX]

It would be nice if we could expose a C API and compile into a static lib so the crate could be linked into already exisitng C programs in order to be used in already existing C applications. This could be especially interesting for once AVR supports lands in rustc, then it could be used in Arduino applications as a safe building stone.

[SkamDart]

@hargoniX looks like no one has taken a stab at this and I would be interested.
Would you feature flag the C FFI then use something like cbindgen to generate C headers using libc for C types in Rust?

[hargoniX]

I would gate it yes, however as of now the public API still requires some alloc (HashSet in specific + some Vecs) so i imagine that might be hard to represent, I got a PR that tries to change that, however I didnt get back to it for quite some while as I've been busy with other things :/

Since its kind of a blocker for you though I'll try to get to it this evening / during the weekend.

Some other API's however shoul mostly be C friendly so you should be good to start off with those why I finish the no_std part.

As for libc, I think that'd be a big no no since we are targeting Embedded here where lots of times no libc is available for use. I could imagine you either working around that by making sure the bindings only expose stuff with C types that are available without C stdlib on a bare metal system...or alternatively handwrite the bindings, I'll leave that up to you!

[SkamDart]

I was thinking of something like this so glibc is only a dependency if you want to use the c_ffi feature.

[package]
name = "nmea"
version = "0.0.9"
authors = ["Felix Obenhuber <felix@obenhuber.de>", "Evgeniy A. Dushistov <dushistov@mail.ru>"]
description = "Simple NMEA 0183 parser"
license = "Apache-2.0"
keywords = ["NMEA", "gps", "glonass", "coordinate", "position"]
repository = "https://github.com/AeroRust/nmea"
documentation = "https://docs.rs/nmea/"
readme = "README.md"
edition = "2018"

[dependencies]
arrayvec = "0.5"
chrono = "0.4"
libc = { version = "0.2.73", optional = true }
nom = "5"

[build-dependencies]
cbindgen = { version = "0.14.3", optional = true }

[features]
c_ffi = ["libc", "cbindgen"]


[dev-dependencies]
quickcheck = "0.9"
approx = "0.3"

[hargoniX]

I'd say we should restrict ourselves to a set of types that are available when using libc in no_std mode (according to their README that's a thing), after all this crate should be usable in environments like Arduino or embedded C running on Cortex-M (or R) etc. which probably only have a subset of C types (and definitely no rust std library). These projects however might want to have a lib that provides them memory save parsing of NMEA packets since C is not very good at parsing (living example, libxml2 fixing memory bugs on a weekly basis)