ffi-convert

Convert between idiomatic Rust values and C-compatible data structures with a minimum of unsafe ceremony.

ffi-convert provides two conversion traits — CReprOf (Rust → C) and AsRust (C → Rust) — plus CDrop and RawPointerConverter to handle ownership of pointer fields, and derive macros that take care of the boilerplate.

use ffi_convert::{AsRust, CDrop, CReprOf};
use libc::{c_char, c_float};

pub struct Pizza {
    pub name: String,
    pub weight: f32,
}

#[repr(C)]
#[derive(CReprOf, AsRust, CDrop)]
#[target_type(Pizza)]
pub struct CPizza {
    pub name: *const c_char,
    pub weight: c_float,
}

let pizza = Pizza { name: "Margarita".to_owned(), weight: 450.0 };
let c_pizza = CPizza::c_repr_of(pizza).unwrap();        // Rust -> C
let again: Pizza = c_pizza.as_rust().unwrap();          // C    -> Rust

Workspace layout

Crate	What's in it
ffi-convert	The conversion traits (CReprOf, AsRust, CDrop, RawPointerConverter, RawBorrow).
ffi-convert-derive	#[derive(...)] macros for all four conversion traits. Re-exported from ffi-convert.
ffi-convert-extra-ctypes	Optional C-compatible containers: CArray<T> (Vec<U>), CStringArray (Vec<String>), CRange<T>.
ffi-convert-tests	Workspace tests, including C round-trip tests with AddressSanitizer / MemorySanitizer.

Full documentation lives on docs.rs/ffi-convert, including the type-mapping table, attribute reference, and caveats that apply to the derives.

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License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.