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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// 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/>.
// Package common contains various helper functions.
package common
import "encoding/hex"
// ToHex returns the hex representation of b, prefixed with '0x'.
// For empty slices, the return value is "0x0".
//
// Deprecated: use hexutil.Encode instead.
func ToHex(b []byte) string {
hex := Bytes2Hex(b)
if len(hex) == 0 {
hex = "0"
}
return "0x" + hex
}
// ToHexArray creates a array of hex-string based on []byte
func ToHexArray(b [][]byte) []string {
r := make([]string, len(b))
for i := range b {
r[i] = ToHex(b[i])
}
return r
}
// FromHex returns the bytes represented by the hexadecimal string s.
// s may be prefixed with "0x".
func FromHex(s string) []byte {
if has0xPrefix(s) {
s = s[2:]
}
if len(s)%2 == 1 {
s = "0" + s
}
return Hex2Bytes(s)
}
// CopyBytes returns an exact copy of the provided bytes.
func CopyBytes(b []byte) (copiedBytes []byte) {
if b == nil {
return nil
}
copiedBytes = make([]byte, len(b))
copy(copiedBytes, b)
return
}
// has0xPrefix validates str begins with '0x' or '0X'.
func has0xPrefix(str string) bool {
return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
}
// isHexCharacter returns bool of c being a valid hexadecimal.
func isHexCharacter(c byte) bool {
return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
}
// isHex validates whether each byte is valid hexadecimal string.
func isHex(str string) bool {
if len(str)%2 != 0 {
return false
}
for _, c := range []byte(str) {
if !isHexCharacter(c) {
return false
}
}
return true
}
// Bytes2Hex returns the hexadecimal encoding of d.
func Bytes2Hex(d []byte) string {
return hex.EncodeToString(d)
}
// Hex2Bytes returns the bytes represented by the hexadecimal string str.
func Hex2Bytes(str string) []byte {
h, _ := hex.DecodeString(str)
return h
}
// Hex2BytesFixed returns bytes of a specified fixed length flen.
func Hex2BytesFixed(str string, flen int) []byte {
h, _ := hex.DecodeString(str)
if len(h) == flen {
return h
}
if len(h) > flen {
return h[len(h)-flen:]
}
hh := make([]byte, flen)
copy(hh[flen-len(h):flen], h)
return hh
}
// RightPadBytes zero-pads slice to the right up to length l.
func RightPadBytes(slice []byte, l int) []byte {
if l <= len(slice) {
return slice
}
padded := make([]byte, l)
copy(padded, slice)
return padded
}
// LeftPadBytes zero-pads slice to the left up to length l.
func LeftPadBytes(slice []byte, l int) []byte {
if l <= len(slice) {
return slice
}
padded := make([]byte, l)
copy(padded[l-len(slice):], slice)
return padded
}
// TrimLeftZeroes returns a subslice of s without leading zeroes
func TrimLeftZeroes(s []byte) []byte {
idx := 0
for ; idx < len(s); idx++ {
if s[idx] != 0 {
break
}
}
return s[idx:]
}
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