# array-section

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When you want to return a buffer of unknown size (but smaller than some limit) from/in a const context.
This crate defines a type backed by an array where only a (contiguous) subsection of the array may be viewed.

This can be useful in const functions that wish to return an array of size `N`,
but with some elements potentially unused.

The crate is `no_std` compatible.

 ```rust
/// Returns an array of the square numbers smaller than both x and N.
const fn squares_smaller_than<const N: usize>(x: usize) -> ArraySection<usize, N> {
    let mut i = 0;
    let mut ans = [0; N];
    while i * i < N && i * i < x {
        ans[i] = i * i;
        i += 1;
    }
    ArraySection::new(ans, 0..i)
}
assert_eq!(squares_smaller_than::<10>(16), [0, 1, 4, 9]);
```

## Feature flags

`std`: lets the error type provide a [`Backtrace`](https://doc.rust-lang.org/std/backtrace/struct.Backtrace.html).
When this feature is disabled the crate is `no_std` compatible. Enables the `alloc` feature.

`alloc`: enables conversion of the array section into `Vec`s and `Box`ed slices.

<br>

### License

<sup>
Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
</sup>

<br>

<sub>
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.
</sub>