1 unstable release
0.5.1 | May 5, 2022 |
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#1739 in Embedded development
63KB
696 lines
BBQueue
BBQueue, short for "BipBuffer Queue", is a Single Producer Single Consumer, lockless, no_std, thread safe, queue, based on BipBuffers. For more info on the design of the lock-free algorithm used by bbqueue, see this blog post.
For a 90 minute guided tour of BBQueue, you can also view this guide on YouTube.
BBQueue is designed (primarily) to be a First-In, First-Out queue for use with DMA on embedded systems.
While Circular/Ring Buffers allow you to send data between two threads (or from an interrupt to main code), you must push the data one piece at a time. With BBQueue, you instead are granted a block of contiguous memory, which can be filled (or emptied) by a DMA engine.
Local usage
// Create a buffer with six elements
let bb: BBBuffer<6> = BBBuffer::new();
let (mut prod, mut cons) = bb.try_split().unwrap();
// Request space for one byte
let mut wgr = prod.grant_exact(1).unwrap();
// Set the data
wgr[0] = 123;
assert_eq!(wgr.len(), 1);
// Make the data ready for consuming
wgr.commit(1);
// Read all available bytes
let rgr = cons.read().unwrap();
assert_eq!(rgr[0], 123);
// Release the space for later writes
rgr.release(1);
Static usage
use bbqueue::BBBuffer;
// Create a buffer with six elements
static BB: BBBuffer<6> = BBBuffer::new();
fn main() {
// Split the bbqueue into producer and consumer halves.
// These halves can be sent to different threads or to
// an interrupt handler for thread safe SPSC usage
let (mut prod, mut cons) = BB.try_split().unwrap();
// Request space for one byte
let mut wgr = prod.grant_exact(1).unwrap();
// Set the data
wgr[0] = 123;
assert_eq!(wgr.len(), 1);
// Make the data ready for consuming
wgr.commit(1);
// Read all available bytes
let rgr = cons.read().unwrap();
assert_eq!(rgr[0], 123);
// Release the space for later writes
rgr.release(1);
// The buffer cannot be split twice
assert!(BB.try_split().is_err());
}
The bbqueue
crate is located in core/
, and tests are located in bbqtest/
.
Features
By default BBQueue uses atomic operations which are available on most platforms. However on some (mostly embedded) platforms atomic support is limited and with the default features you will get a compiler error about missing atomic methods.
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.
Dependencies
~0–335KB