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author | Brian Cully <bjc@kublai.com> | 2019-08-13 11:20:24 -0400 |
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committer | Brian Cully <bjc@kublai.com> | 2019-08-13 11:20:24 -0400 |
commit | 25bbfb332e0edcdc7f3c400d8fc1b83efa9ac6d0 (patch) | |
tree | 35401508aa3555247feab392c006b54c9b22457f | |
parent | eb0a3c051cd52dbc3af44ade4c2afae10eba94ea (diff) | |
download | starb-25bbfb332e0edcdc7f3c400d8fc1b83efa9ac6d0.tar.gz starb-25bbfb332e0edcdc7f3c400d8fc1b83efa9ac6d0.zip |
Documentation.
-rwxr-xr-x | src/lib.rs | 19 |
1 files changed, 19 insertions, 0 deletions
@@ -19,8 +19,12 @@ use core::{ /// This will disappear when const generics appear. const CAPACITY: usize = 1024; +/// Errors that can be made when interacting with the ring buffer. #[derive(Debug, PartialEq)] pub enum Error { + /// The buffer is at capacity and cannot fit any more + /// elements. You need to `unshift` at least once to make some + /// space. BufferFull, } @@ -40,6 +44,9 @@ where T: Copy, { /// Create a new RingBuffer. + /// + /// The `default` element isn't important, but is, unfortunately, + /// currently required to make stable rust happy. pub const fn new(default: T) -> Self { Self { head: AtomicUsize::new(0), @@ -48,6 +55,9 @@ where } } + /// Splits the ring buffer into a consumer/producer pair + /// (`Reader`/`Writer` respectively). These structures can be used + /// safely across threads. // Honestly, this should consume `self` or at least be `mut`, but // it needs to be available in const static contexts, which // prevents that. Basically all the rest of the unsafe stuff in @@ -68,6 +78,7 @@ where } } +/// Consumer of `RingBuffer`. pub struct Reader<'a, T> { rb: *const RingBuffer<T>, _marker: PhantomData<&'a ()>, @@ -75,6 +86,7 @@ pub struct Reader<'a, T> { unsafe impl<T> Send for Reader<'_, T> where T: Send {} unsafe impl<T> Sync for Reader<'_, T> {} +/// Producer for `Ringbuffer`. pub struct Writer<'a, T> { rb: *const RingBuffer<T>, _marker: PhantomData<&'a ()>, @@ -86,6 +98,12 @@ impl<T> Reader<'_, T> where T: Copy, { + /// The number of elements currently available for reading. + /// + /// NB: Because the `Writer` half of the ring buffer may be adding + /// elements in another thread, the value read from `len` is a + /// *minimum* of what may actually be available by the time the + /// reading takes place. pub fn len(&self) -> usize { let rb: &mut RingBuffer<T> = unsafe { core::mem::transmute(self.rb) }; let h = rb.head.load(Ordering::SeqCst); @@ -94,6 +112,7 @@ where rc } + /// Whether or not the ring buffer is empty. pub fn is_empty(&self) -> bool { self.len() == 0 } |