# ringbuf
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[license]: #license
Lock-free single-producer single-consumer (SPSC) FIFO ring buffer with direct access to inner data.
# Overview
`RingBuffer` is the initial structure representing ring buffer itself.
Ring buffer can be splitted into pair of `Producer` and `Consumer`.
`Producer` and `Consumer` are used to append/remove elements to/from the ring buffer accordingly. They can be safely transfered between threads.
Operations with `Producer` and `Consumer` are lock-free - they're succeded or failed immediately without blocking or waiting.
Elements can be effectively appended/removed one by one or many at once.
Also data could be loaded/stored directly into/from [`Read`]/[`Write`] instances.
And finally, there are `unsafe` methods allowing thread-safe direct access in place to the inner memory being appended/removed.
[`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
[`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
When building with nightly toolchain it is possible to run benchmarks via `cargo bench --features benchmark`.
Also the crate could be used with `no_std` (but `alloc` is still required).
# Examples
## Simple example
```rust
use ringbuf::RingBuffer;
let rb = RingBuffer::<i32>::new(2);
let (mut prod, mut cons) = rb.split();
prod.push(0).unwrap();
prod.push(1).unwrap();
assert_eq!(prod.push(2), Err(2));
assert_eq!(cons.pop().unwrap(), 0);
prod.push(2).unwrap();
assert_eq!(cons.pop().unwrap(), 1);
assert_eq!(cons.pop().unwrap(), 2);
assert_eq!(cons.pop(), None);
```
## Message transfer
This is more complicated example of transfering text message between threads.
```rust
use std::io::Read;
use std::thread;
use std::time::Duration;
use ringbuf::RingBuffer;
let buf = RingBuffer::<u8>::new(10);
let (mut prod, mut cons) = buf.split();
let smsg = "The quick brown fox jumps over the lazy dog";
let zero = [0];
let mut bytes = smsg.as_bytes().chain(&zero[..]);
loop {
if prod.is_full() {
println!("-> buffer is full, waiting");
thread::sleep(Duration::from_millis(1));
} else {
let n = prod.read_from(&mut bytes, None).unwrap();
if n == 0 {
break;
}
println!("-> {} bytes sent", n);
}
}
println!("-> message sent");
});
let mut bytes = Vec::<u8>::new();
loop {
if cons.is_empty() {
if bytes.ends_with(&[0]) {
break;
} else {
println!("<- buffer is empty, waiting");
thread::sleep(Duration::from_millis(1));
}
} else {
let n = cons.write_into(&mut bytes, None).unwrap();
println!("<- {} bytes received", n);
}
}
assert_eq!(bytes.pop().unwrap(), 0);
let msg = String::from_utf8(bytes).unwrap();
println!("<- message received: '{}'", msg);
msg
});
pjh.join().unwrap();
let rmsg = cjh.join().unwrap();
assert_eq!(smsg, rmsg);
```
## License
Licensed under either of
* Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](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.