Michal Iskierko
188
vendor/github.com/ethereum/go-ethereum/common/bitutil/bitutil.go
generated
vendored
Normal file
188
vendor/github.com/ethereum/go-ethereum/common/bitutil/bitutil.go
generated
vendored
Normal file
@@ -0,0 +1,188 @@
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// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Adapted from: https://golang.org/src/crypto/cipher/xor.go
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// Package bitutil implements fast bitwise operations.
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package bitutil
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import (
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"runtime"
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"unsafe"
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)
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const wordSize = int(unsafe.Sizeof(uintptr(0)))
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const supportsUnaligned = runtime.GOARCH == "386" || runtime.GOARCH == "amd64" || runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" || runtime.GOARCH == "s390x"
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// XORBytes xors the bytes in a and b. The destination is assumed to have enough
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// space. Returns the number of bytes xor'd.
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func XORBytes(dst, a, b []byte) int {
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if supportsUnaligned {
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return fastXORBytes(dst, a, b)
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}
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return safeXORBytes(dst, a, b)
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}
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// fastXORBytes xors in bulk. It only works on architectures that support
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// unaligned read/writes.
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func fastXORBytes(dst, a, b []byte) int {
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n := len(a)
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if len(b) < n {
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n = len(b)
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}
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w := n / wordSize
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if w > 0 {
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dw := *(*[]uintptr)(unsafe.Pointer(&dst))
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aw := *(*[]uintptr)(unsafe.Pointer(&a))
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bw := *(*[]uintptr)(unsafe.Pointer(&b))
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for i := 0; i < w; i++ {
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dw[i] = aw[i] ^ bw[i]
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}
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}
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for i := n - n%wordSize; i < n; i++ {
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dst[i] = a[i] ^ b[i]
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}
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return n
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}
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// safeXORBytes xors one by one. It works on all architectures, independent if
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// it supports unaligned read/writes or not.
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func safeXORBytes(dst, a, b []byte) int {
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n := len(a)
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if len(b) < n {
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n = len(b)
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}
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for i := 0; i < n; i++ {
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dst[i] = a[i] ^ b[i]
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}
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return n
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}
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// ANDBytes ands the bytes in a and b. The destination is assumed to have enough
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// space. Returns the number of bytes and'd.
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func ANDBytes(dst, a, b []byte) int {
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if supportsUnaligned {
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return fastANDBytes(dst, a, b)
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}
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return safeANDBytes(dst, a, b)
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}
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// fastANDBytes ands in bulk. It only works on architectures that support
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// unaligned read/writes.
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func fastANDBytes(dst, a, b []byte) int {
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n := len(a)
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if len(b) < n {
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n = len(b)
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}
|
||||
w := n / wordSize
|
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if w > 0 {
|
||||
dw := *(*[]uintptr)(unsafe.Pointer(&dst))
|
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aw := *(*[]uintptr)(unsafe.Pointer(&a))
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bw := *(*[]uintptr)(unsafe.Pointer(&b))
|
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for i := 0; i < w; i++ {
|
||||
dw[i] = aw[i] & bw[i]
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||||
}
|
||||
}
|
||||
for i := n - n%wordSize; i < n; i++ {
|
||||
dst[i] = a[i] & b[i]
|
||||
}
|
||||
return n
|
||||
}
|
||||
|
||||
// safeANDBytes ands one by one. It works on all architectures, independent if
|
||||
// it supports unaligned read/writes or not.
|
||||
func safeANDBytes(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
|
||||
}
|
||||
|
||||
// ORBytes ors the bytes in a and b. The destination is assumed to have enough
|
||||
// space. Returns the number of bytes or'd.
|
||||
func ORBytes(dst, a, b []byte) int {
|
||||
if supportsUnaligned {
|
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return fastORBytes(dst, a, b)
|
||||
}
|
||||
return safeORBytes(dst, a, b)
|
||||
}
|
||||
|
||||
// fastORBytes ors in bulk. It only works on architectures that support
|
||||
// unaligned read/writes.
|
||||
func fastORBytes(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
|
||||
}
|
||||
|
||||
// safeORBytes ors one by one. It works on all architectures, independent if
|
||||
// it supports unaligned read/writes or not.
|
||||
func safeORBytes(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
|
||||
}
|
||||
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// TestBytes tests whether any bit is set in the input byte slice.
|
||||
func TestBytes(p []byte) bool {
|
||||
if supportsUnaligned {
|
||||
return fastTestBytes(p)
|
||||
}
|
||||
return safeTestBytes(p)
|
||||
}
|
||||
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||||
// fastTestBytes tests for set bits in bulk. It only works on architectures that
|
||||
// support unaligned read/writes.
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func fastTestBytes(p []byte) bool {
|
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n := len(p)
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w := n / wordSize
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if w > 0 {
|
||||
pw := *(*[]uintptr)(unsafe.Pointer(&p))
|
||||
for i := 0; i < w; i++ {
|
||||
if pw[i] != 0 {
|
||||
return true
|
||||
}
|
||||
}
|
||||
}
|
||||
for i := n - n%wordSize; i < n; i++ {
|
||||
if p[i] != 0 {
|
||||
return true
|
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}
|
||||
}
|
||||
return false
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||||
}
|
||||
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||||
// safeTestBytes tests for set bits one byte at a time. It works on all
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||||
// architectures, independent if it supports unaligned read/writes or not.
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||||
func safeTestBytes(p []byte) bool {
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for i := 0; i < len(p); i++ {
|
||||
if p[i] != 0 {
|
||||
return true
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||||
}
|
||||
}
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||||
return false
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||||
}
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170
vendor/github.com/ethereum/go-ethereum/common/bitutil/compress.go
generated
vendored
Normal file
170
vendor/github.com/ethereum/go-ethereum/common/bitutil/compress.go
generated
vendored
Normal file
@@ -0,0 +1,170 @@
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||||
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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||||
//
|
||||
// The go-ethereum library is free software: you can redistribute it and/or modify
|
||||
// it under the terms of the GNU Lesser General Public License as published by
|
||||
// the Free Software Foundation, either version 3 of the License, or
|
||||
// (at your option) any later version.
|
||||
//
|
||||
// The go-ethereum library is distributed in the hope that it will be useful,
|
||||
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
// GNU Lesser General Public License for more details.
|
||||
//
|
||||
// You should have received a copy of the GNU Lesser General Public License
|
||||
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package bitutil
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||||
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import "errors"
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||||
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var (
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||||
// errMissingData is returned from decompression if the byte referenced by
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// the bitset header overflows the input data.
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errMissingData = errors.New("missing bytes on input")
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// errUnreferencedData is returned from decompression if not all bytes were used
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// up from the input data after decompressing it.
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errUnreferencedData = errors.New("extra bytes on input")
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// errExceededTarget is returned from decompression if the bitset header has
|
||||
// more bits defined than the number of target buffer space available.
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errExceededTarget = errors.New("target data size exceeded")
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// errZeroContent is returned from decompression if a data byte referenced in
|
||||
// the bitset header is actually a zero byte.
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errZeroContent = errors.New("zero byte in input content")
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||||
)
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// The compression algorithm implemented by CompressBytes and DecompressBytes is
|
||||
// optimized for sparse input data which contains a lot of zero bytes. Decompression
|
||||
// requires knowledge of the decompressed data length.
|
||||
//
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// Compression works as follows:
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||||
//
|
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// if data only contains zeroes,
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// CompressBytes(data) == nil
|
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// otherwise if len(data) <= 1,
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||||
// CompressBytes(data) == data
|
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// otherwise:
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||||
// CompressBytes(data) == append(CompressBytes(nonZeroBitset(data)), nonZeroBytes(data)...)
|
||||
// where
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||||
// nonZeroBitset(data) is a bit vector with len(data) bits (MSB first):
|
||||
// nonZeroBitset(data)[i/8] && (1 << (7-i%8)) != 0 if data[i] != 0
|
||||
// len(nonZeroBitset(data)) == (len(data)+7)/8
|
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// nonZeroBytes(data) contains the non-zero bytes of data in the same order
|
||||
|
||||
// CompressBytes compresses the input byte slice according to the sparse bitset
|
||||
// representation algorithm. If the result is bigger than the original input, no
|
||||
// compression is done.
|
||||
func CompressBytes(data []byte) []byte {
|
||||
if out := bitsetEncodeBytes(data); len(out) < len(data) {
|
||||
return out
|
||||
}
|
||||
cpy := make([]byte, len(data))
|
||||
copy(cpy, data)
|
||||
return cpy
|
||||
}
|
||||
|
||||
// bitsetEncodeBytes compresses the input byte slice according to the sparse
|
||||
// bitset representation algorithm.
|
||||
func bitsetEncodeBytes(data []byte) []byte {
|
||||
// Empty slices get compressed to nil
|
||||
if len(data) == 0 {
|
||||
return nil
|
||||
}
|
||||
// One byte slices compress to nil or retain the single byte
|
||||
if len(data) == 1 {
|
||||
if data[0] == 0 {
|
||||
return nil
|
||||
}
|
||||
return data
|
||||
}
|
||||
// Calculate the bitset of set bytes, and gather the non-zero bytes
|
||||
nonZeroBitset := make([]byte, (len(data)+7)/8)
|
||||
nonZeroBytes := make([]byte, 0, len(data))
|
||||
|
||||
for i, b := range data {
|
||||
if b != 0 {
|
||||
nonZeroBytes = append(nonZeroBytes, b)
|
||||
nonZeroBitset[i/8] |= 1 << byte(7-i%8)
|
||||
}
|
||||
}
|
||||
if len(nonZeroBytes) == 0 {
|
||||
return nil
|
||||
}
|
||||
return append(bitsetEncodeBytes(nonZeroBitset), nonZeroBytes...)
|
||||
}
|
||||
|
||||
// DecompressBytes decompresses data with a known target size. If the input data
|
||||
// matches the size of the target, it means no compression was done in the first
|
||||
// place.
|
||||
func DecompressBytes(data []byte, target int) ([]byte, error) {
|
||||
if len(data) > target {
|
||||
return nil, errExceededTarget
|
||||
}
|
||||
if len(data) == target {
|
||||
cpy := make([]byte, len(data))
|
||||
copy(cpy, data)
|
||||
return cpy, nil
|
||||
}
|
||||
return bitsetDecodeBytes(data, target)
|
||||
}
|
||||
|
||||
// bitsetDecodeBytes decompresses data with a known target size.
|
||||
func bitsetDecodeBytes(data []byte, target int) ([]byte, error) {
|
||||
out, size, err := bitsetDecodePartialBytes(data, target)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
if size != len(data) {
|
||||
return nil, errUnreferencedData
|
||||
}
|
||||
return out, nil
|
||||
}
|
||||
|
||||
// bitsetDecodePartialBytes decompresses data with a known target size, but does
|
||||
// not enforce consuming all the input bytes. In addition to the decompressed
|
||||
// output, the function returns the length of compressed input data corresponding
|
||||
// to the output as the input slice may be longer.
|
||||
func bitsetDecodePartialBytes(data []byte, target int) ([]byte, int, error) {
|
||||
// Sanity check 0 targets to avoid infinite recursion
|
||||
if target == 0 {
|
||||
return nil, 0, nil
|
||||
}
|
||||
// Handle the zero and single byte corner cases
|
||||
decomp := make([]byte, target)
|
||||
if len(data) == 0 {
|
||||
return decomp, 0, nil
|
||||
}
|
||||
if target == 1 {
|
||||
decomp[0] = data[0] // copy to avoid referencing the input slice
|
||||
if data[0] != 0 {
|
||||
return decomp, 1, nil
|
||||
}
|
||||
return decomp, 0, nil
|
||||
}
|
||||
// Decompress the bitset of set bytes and distribute the non zero bytes
|
||||
nonZeroBitset, ptr, err := bitsetDecodePartialBytes(data, (target+7)/8)
|
||||
if err != nil {
|
||||
return nil, ptr, err
|
||||
}
|
||||
for i := 0; i < 8*len(nonZeroBitset); i++ {
|
||||
if nonZeroBitset[i/8]&(1<<byte(7-i%8)) != 0 {
|
||||
// Make sure we have enough data to push into the correct slot
|
||||
if ptr >= len(data) {
|
||||
return nil, 0, errMissingData
|
||||
}
|
||||
if i >= len(decomp) {
|
||||
return nil, 0, errExceededTarget
|
||||
}
|
||||
// Make sure the data is valid and push into the slot
|
||||
if data[ptr] == 0 {
|
||||
return nil, 0, errZeroContent
|
||||
}
|
||||
decomp[i] = data[ptr]
|
||||
ptr++
|
||||
}
|
||||
}
|
||||
return decomp, ptr, nil
|
||||
}
|
||||
Reference in New Issue
Block a user