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 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
15use super::block::{Block, BLOCK_LEN};
16
17#[cfg(target_arch = "x86")]
18pub fn shift_full_blocks<F>(in_out: &mut [u8], src: core::ops::RangeFrom<usize>, mut transform: F)
19where
20    F: FnMut(&[u8; BLOCK_LEN]) -> Block,
21{
22    let in_out_len = in_out[src.clone()].len();
23
24    for i in (0..in_out_len).step_by(BLOCK_LEN) {
25        let block = {
26            let input =
27                <&[u8; BLOCK_LEN]>::try_from(&in_out[(src.start + i)..][..BLOCK_LEN]).unwrap();
28            transform(input)
29        };
30        let output = <&mut [u8; BLOCK_LEN]>::try_from(&mut in_out[i..][..BLOCK_LEN]).unwrap();
31        *output = *block.as_ref();
32    }
33}
34
35pub fn shift_partial<F>((in_prefix_len, in_out): (usize, &mut [u8]), transform: F)
36where
37    F: FnOnce(&[u8]) -> Block,
38{
39    let (block, in_out_len) = {
40        let input = &in_out[in_prefix_len..];
41        let in_out_len = input.len();
42        if in_out_len == 0 {
43            return;
44        }
45        debug_assert!(in_out_len < BLOCK_LEN);
46        (transform(input), in_out_len)
47    };
48    in_out[..in_out_len].copy_from_slice(&block.as_ref()[..in_out_len]);
49}
ring/aead/shift.rs

ring/aead/
shift.rs
