1 #![no_std]
2 // Copyright 2023 Google LLC
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 //     http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 
16 //! Crate exposing macros to take array references of slices
17 
18 #[cfg(feature = "std")]
19 extern crate std;
20 
21 /// Generate an array reference to a subset of a slice-able bit of data
22 /// panics if the provided offset and len are out of range of the array
23 #[macro_export]
24 macro_rules! array_ref {
25     ($arr:expr, $offset:expr, $len:expr) => {{
26         let offset = $offset;
27         let slice = &$arr[offset..offset + $len];
28         let result: &[u8; $len] =
29             slice.try_into().expect("array ref len and offset should be valid for provided array");
30         result
31     }};
32 }
33 
34 /// Generates a mutable array reference to a subset of a slice-able bit of data
35 /// panics if the provided offset and len are out of range of the array
36 #[macro_export]
37 macro_rules! array_mut_ref {
38     ($arr:expr, $offset:expr, $len:expr) => {{
39         let offset = $offset;
40         let slice = &mut $arr[offset..offset + $len];
41         let result: &mut [u8; $len] =
42             slice.try_into().expect("array ref len and offset should be valid for provided array");
43         result
44     }};
45 }
46