// Copyright 2024 Brian Smith.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

use super::{BlockLen, CHAINING_WORDS};
use crate::{cpu, polyfill::slice::AsChunks};
use cfg_if::cfg_if;
use core::num::Wrapping;

pub(in super::super) const SHA256_BLOCK_LEN: BlockLen = BlockLen::_512;

pub type State32 = [Wrapping<u32>; CHAINING_WORDS];

pub(crate) fn block_data_order_32(
    state: &mut State32,
    data: AsChunks<u8, { SHA256_BLOCK_LEN.into() }>,
    cpu: cpu::Features,
) {
    cfg_if! {
        if #[cfg(all(target_arch = "aarch64", target_endian = "little"))] {
            use cpu::{GetFeature as _, arm::Sha256};
            if let Some(cpu) = cpu.get_feature() {
                sha2_32_ffi!(unsafe { Sha256 => sha256_block_data_order_hw }, state, data, cpu)
            } else {
                sha2_32_ffi!(unsafe { () => sha256_block_data_order_nohw }, state, data, ())
            }
        } else if #[cfg(all(target_arch = "arm", target_endian = "little"))] {
            use cpu::{GetFeature as _, arm::Neon};
            if let Some(cpu) = cpu.get_feature() {
                sha2_32_ffi!(unsafe { Neon => sha256_block_data_order_neon }, state, data, cpu)
            } else {
                sha2_32_ffi!(unsafe { () => sha256_block_data_order_nohw }, state, data, ())
            }
        } else if #[cfg(target_arch = "x86_64")] {
            use cpu::{GetFeature as _, intel::{Avx, IntelCpu, Sha, Ssse3 }};
            let cpu = cpu.values();
            if let Some(cpu) = cpu.get_feature() {
                sha2_32_ffi!(unsafe { (Sha, Ssse3) => sha256_block_data_order_hw }, state, data, cpu)
            } else if let Some(cpu) = cpu.get_feature() {
                // Pre-Zen AMD CPUs had slow SHLD/SHRD; Zen added the SHA
                // extension; see the discussion in upstream's sha1-586.pl.
                sha2_32_ffi!(unsafe { (Avx, IntelCpu) => sha256_block_data_order_avx }, state, data, cpu)
            } else if let Some(cpu) = cpu.get_feature() {
                sha2_32_ffi!(unsafe { Ssse3 => sha256_block_data_order_ssse3 }, state, data, cpu)
            } else {
                sha2_32_ffi!(unsafe { () => sha256_block_data_order_nohw }, state, data, ())
            }
        } else {
            let _ = cpu; // Unneeded.
            *state = super::fallback::block_data_order(*state, data)
        }
    }
}