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diff --git a/third_party/rust/ringbuf/README.md b/third_party/rust/ringbuf/README.md new file mode 100644 index 0000000000..082cec5074 --- /dev/null +++ b/third_party/rust/ringbuf/README.md @@ -0,0 +1,147 @@ +# ringbuf + +[![Crates.io][crates_badge]][crates] +[![Docs.rs][docs_badge]][docs] +[![Travis CI][travis_badge]][travis] +[![Appveyor][appveyor_badge]][appveyor] +[![Codecov.io][codecov_badge]][codecov] +[![License][license_badge]][license] + +[crates_badge]: https://img.shields.io/crates/v/ringbuf.svg +[docs_badge]: https://docs.rs/ringbuf/badge.svg +[travis_badge]: https://api.travis-ci.org/agerasev/ringbuf.svg +[appveyor_badge]: https://ci.appveyor.com/api/projects/status/github/agerasev/ringbuf?branch=master&svg=true +[codecov_badge]: https://codecov.io/gh/agerasev/ringbuf/graphs/badge.svg +[license_badge]: https://img.shields.io/crates/l/ringbuf.svg + +[crates]: https://crates.io/crates/ringbuf +[docs]: https://docs.rs/ringbuf +[travis]: https://travis-ci.org/agerasev/ringbuf +[appveyor]: https://ci.appveyor.com/project/agerasev/ringbuf +[codecov]: https://codecov.io/gh/agerasev/ringbuf +[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`. + +# 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 pjh = thread::spawn(move || { + println!("-> sending message: '{}'", smsg); + + let zero = [0 as u8]; + 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 cjh = thread::spawn(move || { + println!("<- receiving message"); + + 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. |