compact_arena 0.5.0

A crate with some types to allow indexed arenas with small memory footprint
Documentation 
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use compact_arena::{in_tiny_arena, mk_tiny_arena};

#[cfg(not(any(miri, target_os = "windows")))]
// this will take too much time for miri and won't work on windows
#[test]
fn add_65536_objects() {
    in_tiny_arena!(arena, {
        for _ in 0..=65535 {
            arena.add(42); // all should be ok
        }
    });
}

#[cfg(not(miri))] // miri will fail due to unsafe { panic_impl(&pi) }
#[test]
#[should_panic(expected = "Capacity Exceeded")]
fn add_65537_objects() {
    in_tiny_arena!(arena, {
        for _ in 0..=65535 {
            arena.add(42); // all should be ok
        }
        arena.add(65537); // should panic
    });
}

#[test]
fn two_tiny_arenas() {
    std::thread::Builder::new()
        .stack_size(32 * 1024 * 1024)
        .spawn(|| {
            assert_eq!(
                3,
                in_tiny_arena!(a, {
                    in_tiny_arena!(b, {
                        let x = a.add(1usize);
                        let y = b.add(2usize);
                        a[x] + b[y]
                    })
                })
            )
        })
        .unwrap()
        .join()
        .unwrap();
}

#[test]
fn two_tiny_arenas_one_scope() {
    std::thread::Builder::new()
        .stack_size(32 * 1024 * 1024)
        .spawn(|| {
            mk_tiny_arena!(a);
            mk_tiny_arena!(b);
            let x = a.add(1usize);
            let y = b.add(2usize);
            assert_eq!(3, a[x] + b[y])
        })
        .unwrap()
        .join()
        .unwrap();
}