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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"
)
func ToHex(b []byte) string {
hex := Bytes2Hex(b)
// Prefer output of "0x0" instead of "0x"
if len(hex) == 0 {
hex = "0"
}
return "0x" + hex
}
func FromHex(s string) []byte {
if len(s) > 1 {
if s[0:2] == "0x" || s[0:2] == "0X" {
s = s[2:]
}
if len(s)%2 == 1 {
s = "0" + s
}
return Hex2Bytes(s)
}
return nil
}
// Copy bytes
//
// 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
}
func HasHexPrefix(str string) bool {
l := len(str)
return l >= 2 && str[0:2] == "0x"
}
func IsHex(str string) bool {
l := len(str)
return l >= 4 && l%2 == 0 && str[0:2] == "0x"
}
func Bytes2Hex(d []byte) string {
return hex.EncodeToString(d)
}
func Hex2Bytes(str string) []byte {
h, _ := hex.DecodeString(str)
return h
}
func Hex2BytesFixed(str string, flen int) []byte {
h, _ := hex.DecodeString(str)
if len(h) == flen {
return h
} else {
if len(h) > flen {
return h[len(h)-flen:]
} else {
hh := make([]byte, flen)
copy(hh[flen-len(h):flen], h[:])
return hh
}
}
}
func RightPadBytes(slice []byte, l int) []byte {
if l <= len(slice) {
return slice
}
padded := make([]byte, l)
copy(padded, slice)
return padded
}
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
}
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