ring/aead/
shift.rs

1// Copyright 2018 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 AUTHOR DISCLAIMS ALL WARRANTIES
8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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(target_arch = "x86")]
16pub fn shift_full_blocks<const BLOCK_LEN: usize>(
17    in_out: super::overlapping::Overlapping<'_, u8>,
18    mut transform: impl FnMut(&[u8; BLOCK_LEN]) -> [u8; BLOCK_LEN],
19) {
20    let (in_out, src) = in_out.into_slice_src_mut();
21    let in_out_len = in_out[src.clone()].len();
22
23    for i in (0..in_out_len).step_by(BLOCK_LEN) {
24        let block = {
25            let input =
26                <&[u8; BLOCK_LEN]>::try_from(&in_out[(src.start + i)..][..BLOCK_LEN]).unwrap();
27            transform(input)
28        };
29        let output = <&mut [u8; BLOCK_LEN]>::try_from(&mut in_out[i..][..BLOCK_LEN]).unwrap();
30        *output = block;
31    }
32}