52 lines
1.9 KiB
Rust
52 lines
1.9 KiB
Rust
// Copyright 2018 Brian Smith.
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
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// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
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// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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use super::block::{Block, BLOCK_LEN};
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#[cfg(target_arch = "x86")]
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pub fn shift_full_blocks<F>(in_out: &mut [u8], in_prefix_len: usize, mut transform: F)
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where
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F: FnMut(&[u8; BLOCK_LEN]) -> Block,
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{
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use core::convert::TryFrom;
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let in_out_len = in_out.len().checked_sub(in_prefix_len).unwrap();
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for i in (0..in_out_len).step_by(BLOCK_LEN) {
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let block = {
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let input =
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<&[u8; BLOCK_LEN]>::try_from(&in_out[(in_prefix_len + i)..][..BLOCK_LEN]).unwrap();
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transform(input)
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};
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let output = <&mut [u8; BLOCK_LEN]>::try_from(&mut in_out[i..][..BLOCK_LEN]).unwrap();
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*output = *block.as_ref();
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}
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}
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pub fn shift_partial<F>((in_prefix_len, in_out): (usize, &mut [u8]), transform: F)
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where
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F: FnOnce(&[u8]) -> Block,
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{
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let (block, in_out_len) = {
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let input = &in_out[in_prefix_len..];
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let in_out_len = input.len();
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if in_out_len == 0 {
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return;
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}
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debug_assert!(in_out_len < BLOCK_LEN);
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(transform(input), in_out_len)
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};
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in_out[..in_out_len].copy_from_slice(&block.as_ref()[..in_out_len]);
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}
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