ringbuf 0.4.8

Lock-free SPSC FIFO ring buffer with direct access to inner data
Documentation 
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use super::Rb;
use crate::{storage::Array, traits::*};

fn indices(this: impl Observer) -> (usize, usize) {
    (this.read_index(), this.write_index())
}

#[test]
fn capacity() {
    const CAP: usize = 13;
    let rb = Rb::<Array<i32, CAP>>::default();
    assert_eq!(rb.capacity().get(), CAP);
}
#[test]
fn split_capacity() {
    const CAP: usize = 13;
    let mut rb = Rb::<Array<i32, CAP>>::default();
    let (prod, cons) = rb.split_ref();

    assert_eq!(prod.capacity().get(), CAP);
    assert_eq!(cons.capacity().get(), CAP);
}

#[test]
fn try_push() {
    let mut rb = Rb::<Array<i32, 2>>::default();
    let (mut prod, _) = rb.split_ref();

    assert_eq!(indices(prod.observe()), (0, 0));

    assert_eq!(prod.try_push(123), Ok(()));
    assert_eq!(indices(prod.observe()), (0, 1));

    assert_eq!(prod.try_push(234), Ok(()));
    assert_eq!(indices(prod.observe()), (0, 2));

    assert_eq!(prod.try_push(345), Err(345));
    assert_eq!(indices(prod.observe()), (0, 2));
}

#[test]
fn pop_empty() {
    let mut rb = Rb::<Array<i32, 2>>::default();
    let (_, mut cons) = rb.split_ref();

    assert_eq!(indices(cons.observe()), (0, 0));

    assert_eq!(cons.try_pop(), None);
    assert_eq!(indices(cons.observe()), (0, 0));
}

#[test]
fn push_pop_one() {
    const CAP: usize = 2;
    let mut rb = Rb::<Array<i32, CAP>>::default();
    let (mut prod, mut cons) = rb.split_ref();

    const MOD: usize = 2 * CAP;
    let values = [12, 34, 56, 78, 90];
    assert_eq!(indices(cons.observe()), (0, 0));

    for (i, v) in values.iter().enumerate() {
        assert_eq!(prod.try_push(*v), Ok(()));
        assert_eq!(indices(cons.observe()), (i % MOD, (i + 1) % MOD));

        assert_eq!(cons.try_pop().unwrap(), *v);
        assert_eq!(indices(cons.observe()), ((i + 1) % MOD, (i + 1) % MOD));

        assert_eq!(cons.try_pop(), None);
        assert_eq!(indices(cons.observe()), ((i + 1) % MOD, (i + 1) % MOD));
    }
}

#[test]
fn push_pop_all() {
    const CAP: usize = 2;
    let mut rb = Rb::<Array<i32, CAP>>::default();
    let (mut prod, mut cons) = rb.split_ref();

    const MOD: usize = 2 * CAP;
    let values = [(12, 34, 13), (56, 78, 57), (90, 10, 91)];
    assert_eq!(indices(cons.observe()), (0, 0));

    for (i, v) in values.iter().enumerate() {
        assert_eq!(prod.try_push(v.0), Ok(()));
        assert_eq!(indices(cons.observe()), (CAP * i % MOD, (CAP * i + 1) % MOD));

        assert_eq!(prod.try_push(v.1), Ok(()));
        assert_eq!(indices(cons.observe()), (CAP * i % MOD, (CAP * i + 2) % MOD));

        assert_eq!(prod.try_push(v.2).unwrap_err(), v.2);
        assert_eq!(indices(cons.observe()), (CAP * i % MOD, (CAP * i + 2) % MOD));

        assert_eq!(cons.try_pop().unwrap(), v.0);
        assert_eq!(indices(cons.observe()), ((CAP * i + 1) % MOD, (CAP * i + 2) % MOD));

        assert_eq!(cons.try_pop().unwrap(), v.1);
        assert_eq!(indices(cons.observe()), ((CAP * i + 2) % MOD, (CAP * i + 2) % MOD));

        assert_eq!(cons.try_pop(), None);
        assert_eq!(indices(cons.observe()), ((CAP * i + 2) % MOD, (CAP * i + 2) % MOD));
    }
}

#[test]
fn empty_full() {
    let mut rb = Rb::<Array<i32, 1>>::default();
    let (mut prod, cons) = rb.split_ref();

    assert!(prod.is_empty());
    assert!(cons.is_empty());
    assert!(!prod.is_full());
    assert!(!cons.is_full());

    assert_eq!(prod.try_push(123), Ok(()));

    assert!(!prod.is_empty());
    assert!(!cons.is_empty());
    assert!(prod.is_full());
    assert!(cons.is_full());
}

#[test]
fn len_remaining() {
    let mut rb = Rb::<Array<i32, 2>>::default();
    let (mut prod, mut cons) = rb.split_ref();

    assert_eq!(prod.occupied_len(), 0);
    assert_eq!(cons.occupied_len(), 0);
    assert_eq!(prod.vacant_len(), 2);
    assert_eq!(cons.vacant_len(), 2);

    assert_eq!(prod.try_push(123), Ok(()));

    assert_eq!(prod.occupied_len(), 1);
    assert_eq!(cons.occupied_len(), 1);
    assert_eq!(prod.vacant_len(), 1);
    assert_eq!(cons.vacant_len(), 1);

    assert_eq!(prod.try_push(456), Ok(()));

    assert_eq!(prod.occupied_len(), 2);
    assert_eq!(cons.occupied_len(), 2);
    assert_eq!(prod.vacant_len(), 0);
    assert_eq!(cons.vacant_len(), 0);

    assert_eq!(cons.try_pop(), Some(123));

    assert_eq!(prod.occupied_len(), 1);
    assert_eq!(cons.occupied_len(), 1);
    assert_eq!(prod.vacant_len(), 1);
    assert_eq!(cons.vacant_len(), 1);

    assert_eq!(cons.try_pop(), Some(456));

    assert_eq!(prod.occupied_len(), 0);
    assert_eq!(cons.occupied_len(), 0);
    assert_eq!(prod.vacant_len(), 2);
    assert_eq!(cons.vacant_len(), 2);

    assert_eq!(prod.try_push(789), Ok(()));

    assert_eq!(prod.occupied_len(), 1);
    assert_eq!(cons.occupied_len(), 1);
    assert_eq!(prod.vacant_len(), 1);
    assert_eq!(cons.vacant_len(), 1);
}