buffin_derive

This crate should be used together with the buffin crate.

This crate enables you to automatically derive ToBytes and FromBytes for custom structs and enums, provided all fields within them implement ToBytes and FromBytes, respectively.

use buffin::Buffin;
use buffin_derive::{FromBytes, ToBytes};

#[derive(ToBytes, FromBytes)]
struct MyStruct {
    number: u16,
    text: String,
}

#[derive(ToBytes, FromBytes)]
enum MyEnum {
    #[tag("vnt1")]
    Variant1 {
        my_struct: MyStruct,
    },
}

// snip //

let my_enum = MyEnum::Variant1 {
    my_struct: MyStruct {
        number: 12,
        text: "letters and things".to_string(),
    }
};

// Grab a bit of memory and stuff it in a Buffin instance.
// This can also be a vec. Keep in mind that the vec will never be resized.
let mut buffer = [0; 1024];
let mut buffer = Buffin::new(&mut buffer);

// Put my_enum in the buffin.
buffer.add(&my_enum).expect("failed to add my_enum");

// Check how many bytes we've used.
println!("buffer length: {}", buffer.len());

// Take it back out again.
let my_parsed_enum = buffer.pop::<MyEnum>().expect("failed to parse");

It's possible to serialize multiple things into the same buffer.

#[derive(Debug, ToBytes, FromBytes)]
enum Message {
    #[tag("j")]
    Join { channel: String },
    #[tag("l")]
    Leave { channel: String },
    #[tag("s")]
    Say { channel: String, message: String }
}

// snip //

let mut buffer = [0; 1024];
let mut buffer = Buffin::new(&mut buffer);

// Put some messages in the buffin.
buffer.add(&Message::Join { channel: "ch1".to_string() }).expect("failed to add message");
buffer.add(&Message::Say { channel: "ch1".to_string(), message: "Woop woop".to_string() }).expect("failed to add message");
buffer.add(&Message::Leave { channel: "ch1".to_string() }).expect("failed to add message");

// Check how many bytes we've used. It should be 37.
println!("buffer length: {}", buffer.len());

// Read them all back out again.
while let Ok(message) = buffer.pop::<Message>() {
    println!("message: {message:?}");
}