// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build (amd64 || 386 || ppc64le) && !purego

package sha3

import (
	"encoding/binary"
	"unsafe"
)

// A storageBuf is an aligned array of maxRate bytes.
type storageBuf [maxRate / 8]uint64

func (b *storageBuf) asBytes() *[maxRate]byte {
	return (*[maxRate]byte)(unsafe.Pointer(b))
}

// xorInUnaligned uses unaligned reads and writes to update d.a to contain d.a
// XOR buf.
func xorInUnaligned(d *HasherState, buf []byte) {
	n := len(buf)
	if n >= 72 {
		d.a[0] ^= binary.LittleEndian.Uint64(buf[8*0:])
		d.a[1] ^= binary.LittleEndian.Uint64(buf[8*1:])
		d.a[2] ^= binary.LittleEndian.Uint64(buf[8*2:])
		d.a[3] ^= binary.LittleEndian.Uint64(buf[8*3:])
		d.a[4] ^= binary.LittleEndian.Uint64(buf[8*4:])
		d.a[5] ^= binary.LittleEndian.Uint64(buf[8*5:])
		d.a[6] ^= binary.LittleEndian.Uint64(buf[8*6:])
		d.a[7] ^= binary.LittleEndian.Uint64(buf[8*7:])
		d.a[8] ^= binary.LittleEndian.Uint64(buf[8*8:])
	}
	if n >= 104 {
		d.a[9] ^= binary.LittleEndian.Uint64(buf[8*9:])
		d.a[10] ^= binary.LittleEndian.Uint64(buf[8*10:])
		d.a[11] ^= binary.LittleEndian.Uint64(buf[8*11:])
		d.a[12] ^= binary.LittleEndian.Uint64(buf[8*12:])
	}
	if n >= 136 {
		d.a[13] ^= binary.LittleEndian.Uint64(buf[8*13:])
		d.a[14] ^= binary.LittleEndian.Uint64(buf[8*14:])
		d.a[15] ^= binary.LittleEndian.Uint64(buf[8*15:])
		d.a[16] ^= binary.LittleEndian.Uint64(buf[8*16:])
	}
	if n >= 144 {
		d.a[17] ^= binary.LittleEndian.Uint64(buf[8*17:])
	}
	if n >= 168 {
		d.a[18] ^= binary.LittleEndian.Uint64(buf[8*18:])
		d.a[19] ^= binary.LittleEndian.Uint64(buf[8*19:])
		d.a[20] ^= binary.LittleEndian.Uint64(buf[8*20:])
	}
}

func copyOutUnaligned(d *HasherState, buf []byte) {
	ab := (*[maxRate]uint8)(unsafe.Pointer(&d.a[0]))
	copy(buf, ab[:])
}

func xorIn(d *HasherState, buf []byte) {
	xorInUnaligned(d, buf)
}

var (
	copyOut = copyOutUnaligned
)

const xorImplementationUnaligned = "unaligned"