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
15 use super::block::{Block, BLOCK_LEN};
16
17 #[cfg(target_arch = "x86")]
shift_full_blocks<F>(in_out: &mut [u8], in_prefix_len: usize, mut transform: F) where F: FnMut(&[u8; BLOCK_LEN]) -> Block,18 pub fn shift_full_blocks<F>(in_out: &mut [u8], in_prefix_len: usize, mut transform: F)
19 where
20 F: FnMut(&[u8; BLOCK_LEN]) -> Block,
21 {
22 use core::convert::TryFrom;
23
24 let in_out_len = in_out.len().checked_sub(in_prefix_len).unwrap();
25
26 for i in (0..in_out_len).step_by(BLOCK_LEN) {
27 let block = {
28 let input =
29 <&[u8; BLOCK_LEN]>::try_from(&in_out[(in_prefix_len + i)..][..BLOCK_LEN]).unwrap();
30 transform(input)
31 };
32 let output = <&mut [u8; BLOCK_LEN]>::try_from(&mut in_out[i..][..BLOCK_LEN]).unwrap();
33 *output = *block.as_ref();
34 }
35 }
36
shift_partial<F>((in_prefix_len, in_out): (usize, &mut [u8]), transform: F) where F: FnOnce(&[u8]) -> Block,37 pub fn shift_partial<F>((in_prefix_len, in_out): (usize, &mut [u8]), transform: F)
38 where
39 F: FnOnce(&[u8]) -> Block,
40 {
41 let (block, in_out_len) = {
42 let input = &in_out[in_prefix_len..];
43 let in_out_len = input.len();
44 if in_out_len == 0 {
45 return;
46 }
47 debug_assert!(in_out_len < BLOCK_LEN);
48 (transform(input), in_out_len)
49 };
50 in_out[..in_out_len].copy_from_slice(&block.as_ref()[..in_out_len]);
51 }
52