gaspersic/go-ethereum
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

common/bitutil, consensus/ethash: reusable bitutil package

Browse Source
This commit is contained in:
Péter Szilágyi
2017-05-05 16:00:11 +03:00
parent 93832b633e
commit 36a800a1d2
4 changed files with 405 additions and 86 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
consensus/ethash/algorithm.go
View File

@ -27,6 +27,7 @@ import (
"unsafe"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/bitutil"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/crypto/sha3"
"github.com/ethereum/go-ethereum/log"
@ -142,7 +143,7 @@ func generateCache(dest []uint32, epoch uint64, seed []byte) {
dstOff = j * hashBytes
xorOff = (binary.LittleEndian.Uint32(cache[dstOff:]) % uint32(rows)) * hashBytes
)
xorBytes(temp, cache[srcOff:srcOff+hashBytes], cache[xorOff:xorOff+hashBytes])
bitutil.XORBytes(temp, cache[srcOff:srcOff+hashBytes], cache[xorOff:xorOff+hashBytes])
keccak512(cache[dstOff:], temp)
atomic.AddUint32(&progress, 1)

85
consensus/ethash/xor.go
View File

@ -1,85 +0,0 @@
// 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.
// Source: https://golang.org/src/crypto/cipher/xor.go
package ethash
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)
}
// 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)
}
}