use std::os::raw::c_void;





struct Encoder<TCallback>
where
    TCallback: Fn(&[u8]),
{
    callback: TCallback,
}





type EncoderType = Encoder<Box<Fn(&[u8])>>;

#[no_mangle]
unsafe extern "C" fn encoder_create(
    on_data: unsafe extern "C" fn(data: *const u8, length: usize),
    instance: *mut *mut c_void,
) -> bool {
    let encoder: EncoderType = Encoder {
        callback: move |data| unsafe { (on_data)(data.as_ptr(), data.len()) },
    };

    *instance = Box::into_raw(Box::new(encoder)) as *mut c_void;
    true
}

#[no_mangle]
pub unsafe extern "C" fn encoder_destroy(instance: *mut c_void) {
    if !instance.is_null() {
        Box::from_raw(instance as *mut EncoderType);
    }
}




fn main() {
    println!("Hello, world!");
}