xor_unaligned.go

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