1// Copyright 2015 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package sha3
6
7import (
8	"crypto/subtle"
9	"encoding/binary"
10	"unsafe"
11
12	"golang.org/x/sys/cpu"
13)
14
15// xorIn xors the bytes in buf into the state.
16func xorIn(d *state, buf []byte) {
17	if cpu.IsBigEndian {
18		for i := 0; len(buf) >= 8; i++ {
19			a := binary.LittleEndian.Uint64(buf)
20			d.a[i] ^= a
21			buf = buf[8:]
22		}
23	} else {
24		ab := (*[25 * 64 / 8]byte)(unsafe.Pointer(&d.a))
25		subtle.XORBytes(ab[:], ab[:], buf)
26	}
27}
28
29// copyOut copies uint64s to a byte buffer.
30func copyOut(d *state, b []byte) {
31	if cpu.IsBigEndian {
32		for i := 0; len(b) >= 8; i++ {
33			binary.LittleEndian.PutUint64(b, d.a[i])
34			b = b[8:]
35		}
36	} else {
37		ab := (*[25 * 64 / 8]byte)(unsafe.Pointer(&d.a))
38		copy(b, ab[:])
39	}
40}
41