xor_unaligned.go

Documentation: golang.org/x/crypto/sha3

     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  
     5  //go:build (amd64 || 386 || ppc64le) && !purego
     6  
     7  package sha3
     8  
     9  import "unsafe"
    10  
    11  // A storageBuf is an aligned array of maxRate bytes.
    12  type storageBuf [maxRate / 8]uint64
    13  
    14  func (b *storageBuf) asBytes() *[maxRate]byte {
    15  	return (*[maxRate]byte)(unsafe.Pointer(b))
    16  }
    17  
    18  // xorInUnaligned uses unaligned reads and writes to update d.a to contain d.a
    19  // XOR buf.
    20  func xorInUnaligned(d *state, buf []byte) {
    21  	n := len(buf)
    22  	bw := (*[maxRate / 8]uint64)(unsafe.Pointer(&buf[0]))[: n/8 : n/8]
    23  	if n >= 72 {
    24  		d.a[0] ^= bw[0]
    25  		d.a[1] ^= bw[1]
    26  		d.a[2] ^= bw[2]
    27  		d.a[3] ^= bw[3]
    28  		d.a[4] ^= bw[4]
    29  		d.a[5] ^= bw[5]
    30  		d.a[6] ^= bw[6]
    31  		d.a[7] ^= bw[7]
    32  		d.a[8] ^= bw[8]
    33  	}
    34  	if n >= 104 {
    35  		d.a[9] ^= bw[9]
    36  		d.a[10] ^= bw[10]
    37  		d.a[11] ^= bw[11]
    38  		d.a[12] ^= bw[12]
    39  	}
    40  	if n >= 136 {
    41  		d.a[13] ^= bw[13]
    42  		d.a[14] ^= bw[14]
    43  		d.a[15] ^= bw[15]
    44  		d.a[16] ^= bw[16]
    45  	}
    46  	if n >= 144 {
    47  		d.a[17] ^= bw[17]
    48  	}
    49  	if n >= 168 {
    50  		d.a[18] ^= bw[18]
    51  		d.a[19] ^= bw[19]
    52  		d.a[20] ^= bw[20]
    53  	}
    54  }
    55  
    56  func copyOutUnaligned(d *state, buf []byte) {
    57  	ab := (*[maxRate]uint8)(unsafe.Pointer(&d.a[0]))
    58  	copy(buf, ab[:])
    59  }
    60  
    61  var (
    62  	xorIn   = xorInUnaligned
    63  	copyOut = copyOutUnaligned
    64  )
    65  
    66  const xorImplementationUnaligned = "unaligned"
    67
View as plain text