b64-ct 0.1.3

Fast and secure Base64 encoding/decoding. This crate provides an implementation of Base64 encoding/decoding that is designed to be resistant against software side-channel attacks (such as timing & cache attacks), see the documentation for details. On certain platforms it also uses SIMD making it very fast. This makes it suitable for e.g. decoding cryptographic private keys in PEM format. The API is very similar to the base64 implementation in the old rustc-serialize crate, making it easy to use in existing projects.
Documentation 
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/* Copyright (c) Fortanix, Inc.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#[cfg(target_arch = "x86")]
use core::arch::x86::*;
#[cfg(target_arch = "x86_64")]
use core::arch::x86_64::*;

#[rustfmt::skip]
pub(crate) unsafe fn dup_mm_setr_epi8(e: [i8; 16]) -> __m256i {
    _mm256_setr_epi8(
        e[0x0], e[0x1], e[0x2], e[0x3], e[0x4], e[0x5], e[0x6], e[0x7], 
        e[0x8], e[0x9], e[0xa], e[0xb], e[0xc], e[0xd], e[0xe], e[0xf], 
        e[0x0], e[0x1], e[0x2], e[0x3], e[0x4], e[0x5], e[0x6], e[0x7], 
        e[0x8], e[0x9], e[0xa], e[0xb], e[0xc], e[0xd], e[0xe], e[0xf], 
    )
}

#[rustfmt::skip]
pub(crate) unsafe fn dup_mm_setr_epu8(e: [u8; 16]) -> __m256i {
    _mm256_setr_epi8(
        e[0x0] as _, e[0x1] as _, e[0x2] as _, e[0x3] as _, e[0x4] as _, e[0x5] as _, e[0x6] as _, e[0x7] as _, 
        e[0x8] as _, e[0x9] as _, e[0xa] as _, e[0xb] as _, e[0xc] as _, e[0xd] as _, e[0xe] as _, e[0xf] as _, 
        e[0x0] as _, e[0x1] as _, e[0x2] as _, e[0x3] as _, e[0x4] as _, e[0x5] as _, e[0x6] as _, e[0x7] as _, 
        e[0x8] as _, e[0x9] as _, e[0xa] as _, e[0xb] as _, e[0xc] as _, e[0xd] as _, e[0xe] as _, e[0xf] as _, 
    )
}

pub(crate) unsafe fn _mm256_not_si256(i: __m256i) -> __m256i {
    _mm256_xor_si256(i, _mm256_set1_epi8(!0))
}

pub(crate) unsafe fn array_as_m256i(v: [u8; 32]) -> __m256i {
    core::mem::transmute(v)
}

pub(crate) unsafe fn m256i_as_array(v: __m256i) -> [u8; 32] {
    core::mem::transmute(v)
}