1// Copyright 2024 Brian Smith.
2//
3// Permission to use, copy, modify, and/or distribute this software for any
4// purpose with or without fee is hereby granted, provided that the above
5// copyright notice and this permission notice appear in all copies.
6//
7// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
10// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
14
15#![cfg_attr(not(test), allow(dead_code))]
16
17use super::Overlapping;
18use crate::error::LenMismatchError;
19use core::array::TryFromSliceError;
20
21pub struct Array<'o, T, const N: usize> {
22 // Invariant: N != 0.
23 // Invariant: `self.in_out.len() == N`.
24 in_out: Overlapping<'o, T>,
25}
26
27impl<'o, T, const N: usize> Array<'o, T, N> {
28 pub(super) fn new(in_out: Overlapping<'o, T>) -> Result<Self, LenMismatchError> {
29 if N == 0 || in_out.len() != N {
30 return Err(LenMismatchError::new(N));
31 }
32 Ok(Self { in_out })
33 }
34
35 pub fn into_unwritten_output(self) -> &'o mut [T; N]
36 where
37 &'o mut [T]: TryInto<&'o mut [T; N], Error = TryFromSliceError>,
38 {
39 self.in_out
40 .into_unwritten_output()
41 .try_into()
42 .unwrap_or_else(|TryFromSliceError { .. }| {
43 unreachable!() // Due to invariant
44 })
45 }
46}
47
48impl<T, const N: usize> Array<'_, T, N> {
49 pub fn input<'s>(&'s self) -> &'s [T; N]
50 where
51 &'s [T]: TryInto<&'s [T; N], Error = TryFromSliceError>,
52 {
53 self.in_out
54 .input()
55 .try_into()
56 .unwrap_or_else(|TryFromSliceError { .. }| {
57 unreachable!() // Due to invariant
58 })
59 }
60}
61