mirror of
https://github.com/woodpecker-ci/woodpecker.git
synced 2024-12-18 08:26:45 +02:00
85 lines
2.0 KiB
Go
85 lines
2.0 KiB
Go
// Copyright 2013 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.
|
|
|
|
package aes12
|
|
|
|
import (
|
|
"runtime"
|
|
"unsafe"
|
|
)
|
|
|
|
const wordSize = int(unsafe.Sizeof(uintptr(0)))
|
|
const supportsUnaligned = runtime.GOARCH == "386" || runtime.GOARCH == "amd64" || runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" || runtime.GOARCH == "s390x"
|
|
|
|
// fastXORBytes xors in bulk. It only works on architectures that
|
|
// support unaligned read/writes.
|
|
func fastXORBytes(dst, a, b []byte) int {
|
|
n := len(a)
|
|
if len(b) < n {
|
|
n = len(b)
|
|
}
|
|
|
|
w := n / wordSize
|
|
if w > 0 {
|
|
dw := *(*[]uintptr)(unsafe.Pointer(&dst))
|
|
aw := *(*[]uintptr)(unsafe.Pointer(&a))
|
|
bw := *(*[]uintptr)(unsafe.Pointer(&b))
|
|
for i := 0; i < w; i++ {
|
|
dw[i] = aw[i] ^ bw[i]
|
|
}
|
|
}
|
|
|
|
for i := (n - n%wordSize); i < n; i++ {
|
|
dst[i] = a[i] ^ b[i]
|
|
}
|
|
|
|
return n
|
|
}
|
|
|
|
func safeXORBytes(dst, a, b []byte) int {
|
|
n := len(a)
|
|
if len(b) < n {
|
|
n = len(b)
|
|
}
|
|
for i := 0; i < n; i++ {
|
|
dst[i] = a[i] ^ b[i]
|
|
}
|
|
return n
|
|
}
|
|
|
|
// xorBytes xors the bytes in a and b. The destination is assumed to have enough
|
|
// space. Returns the number of bytes xor'd.
|
|
func xorBytes(dst, a, b []byte) int {
|
|
if supportsUnaligned {
|
|
return fastXORBytes(dst, a, b)
|
|
} else {
|
|
// TODO(hanwen): if (dst, a, b) have common alignment
|
|
// we could still try fastXORBytes. It is not clear
|
|
// how often this happens, and it's only worth it if
|
|
// the block encryption itself is hardware
|
|
// accelerated.
|
|
return safeXORBytes(dst, a, b)
|
|
}
|
|
}
|
|
|
|
// fastXORWords XORs multiples of 4 or 8 bytes (depending on architecture.)
|
|
// The arguments are assumed to be of equal length.
|
|
func fastXORWords(dst, a, b []byte) {
|
|
dw := *(*[]uintptr)(unsafe.Pointer(&dst))
|
|
aw := *(*[]uintptr)(unsafe.Pointer(&a))
|
|
bw := *(*[]uintptr)(unsafe.Pointer(&b))
|
|
n := len(b) / wordSize
|
|
for i := 0; i < n; i++ {
|
|
dw[i] = aw[i] ^ bw[i]
|
|
}
|
|
}
|
|
|
|
func xorWords(dst, a, b []byte) {
|
|
if supportsUnaligned {
|
|
fastXORWords(dst, a, b)
|
|
} else {
|
|
safeXORBytes(dst, a, b)
|
|
}
|
|
}
|