140 lines
3.3 KiB
Go
140 lines
3.3 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package common contains various helper functions.
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package common
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import (
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"encoding/hex"
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)
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// FromHex returns the bytes represented by the hexadecimal string s.
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// s may be prefixed with "0x".
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func FromHex(s string) []byte {
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if has0xPrefix(s) {
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s = s[2:]
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}
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if len(s)%2 == 1 {
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s = "0" + s
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}
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return Hex2Bytes(s)
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}
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// CopyBytes returns an exact copy of the provided bytes.
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func CopyBytes(b []byte) (copiedBytes []byte) {
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if b == nil {
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return nil
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}
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copiedBytes = make([]byte, len(b))
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copy(copiedBytes, b)
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return
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}
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// has0xPrefix validates str begins with '0x' or '0X'.
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func has0xPrefix(str string) bool {
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return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
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}
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// isHexCharacter returns bool of c being a valid hexadecimal.
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func isHexCharacter(c byte) bool {
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return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
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}
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// isHex validates whether each byte is valid hexadecimal string.
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func isHex(str string) bool {
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if len(str)%2 != 0 {
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return false
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}
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for _, c := range []byte(str) {
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if !isHexCharacter(c) {
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return false
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}
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}
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return true
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}
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// Bytes2Hex returns the hexadecimal encoding of d.
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func Bytes2Hex(d []byte) string {
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return hex.EncodeToString(d)
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}
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// Hex2Bytes returns the bytes represented by the hexadecimal string str.
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func Hex2Bytes(str string) []byte {
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h, _ := hex.DecodeString(str)
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return h
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}
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// Hex2BytesFixed returns bytes of a specified fixed length flen.
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func Hex2BytesFixed(str string, flen int) []byte {
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h, _ := hex.DecodeString(str)
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if len(h) == flen {
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return h
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}
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if len(h) > flen {
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return h[len(h)-flen:]
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}
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hh := make([]byte, flen)
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copy(hh[flen-len(h):flen], h)
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return hh
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}
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// RightPadBytes zero-pads slice to the right up to length l.
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func RightPadBytes(slice []byte, l int) []byte {
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if l <= len(slice) {
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return slice
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}
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padded := make([]byte, l)
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copy(padded, slice)
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return padded
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}
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// LeftPadBytes zero-pads slice to the left up to length l.
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func LeftPadBytes(slice []byte, l int) []byte {
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if l <= len(slice) {
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return slice
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}
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padded := make([]byte, l)
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copy(padded[l-len(slice):], slice)
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return padded
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}
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// TrimLeftZeroes returns a subslice of s without leading zeroes
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func TrimLeftZeroes(s []byte) []byte {
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idx := 0
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for ; idx < len(s); idx++ {
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if s[idx] != 0 {
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break
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}
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}
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return s[idx:]
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}
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// TrimRightZeroes returns a subslice of s without trailing zeroes
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func TrimRightZeroes(s []byte) []byte {
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idx := len(s)
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for ; idx > 0; idx-- {
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if s[idx-1] != 0 {
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break
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}
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}
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return s[:idx]
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}
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