// 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 (
"bytes"
"encoding/binary"
"encoding/hex"
"fmt"
"math/big"
"strings"
)
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 = s[2:]
}
if len(s)%2 == 1 {
s = "0" + s
}
return Hex2Bytes(s)
}
return nil
}
type Bytes []byte
func (self Bytes) String() string {
return string(self)
}
func DeleteFromByteSlice(s [][]byte, hash []byte) [][]byte {
for i, h := range s {
if bytes.Compare(h, hash) == 0 {
return append(s[:i:i], s[i+1:]...)
}
}
return s
}
// Number to bytes
//
// Returns the number in bytes with the specified base
func NumberToBytes(num interface{}, bits int) []byte {
buf := new(bytes.Buffer)
err := binary.Write(buf, binary.BigEndian, num)
if err != nil {
fmt.Println("NumberToBytes failed:", err)
}
return buf.Bytes()[buf.Len()-(bits/8):]
}
// Bytes to number
//
// Attempts to cast a byte slice to a unsigned integer
func BytesToNumber(b []byte) uint64 {
var number uint64
// Make sure the buffer is 64bits
data := make([]byte, 8)
data = append(data[:len(b)], b...)
buf := bytes.NewReader(data)
err := binary.Read(buf, binary.BigEndian, &number)
if err != nil {
fmt.Println("BytesToNumber failed:", err)
}
return number
}
// Read variable int
//
// Read a variable length number in big endian byte order
func ReadVarInt(buff []byte) (ret uint64) {
switch l := len(buff); {
case l > 4:
d := LeftPadBytes(buff, 8)
binary.Read(bytes.NewReader(d), binary.BigEndian, &ret)
case l > 2:
var num uint32
d := LeftPadBytes(buff, 4)
binary.Read(bytes.NewReader(d), binary.BigEndian, &num)
ret = uint64(num)
case l > 1:
var num uint16
d := LeftPadBytes(buff, 2)
binary.Read(bytes.NewReader(d), binary.BigEndian, &num)
ret = uint64(num)
default:
var num uint8
binary.Read(bytes.NewReader(buff), binary.BigEndian, &num)
ret = uint64(num)
}
return
}
// Copy bytes
//
// Returns an exact copy of the provided bytes
func CopyBytes(b []byte) (copiedBytes []byte) {
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 : len(h)]
} else {
hh := make([]byte, flen)
copy(hh[flen-len(h):flen], h[:])
return hh
}
}
}
func StringToByteFunc(str string, cb func(str string) []byte) (ret []byte) {
if len(str) > 1 && str[0:2] == "0x" && !strings.Contains(str, "\n") {
ret = Hex2Bytes(str[2:])
} else {
ret = cb(str)
}
return
}
func FormatData(data string) []byte {
if len(data) == 0 {
return nil
}
// Simple stupid
d := new(big.Int)
if data[0:1] == "\"" && data[len(data)-1:] == "\"" {
return RightPadBytes([]byte(data[1:len(data)-1]), 32)
} else if len(data) > 1 && data[:2] == "0x" {
d.SetBytes(Hex2Bytes(data[2:]))
} else {
d.SetString(data, 0)
}
return BigToBytes(d, 256)
}
func ParseData(data ...interface{}) (ret []byte) {
for _, item := range data {
switch t := item.(type) {
case string:
var str []byte
if IsHex(t) {
str = Hex2Bytes(t[2:])
} else {
str = []byte(t)
}
ret = append(ret, RightPadBytes(str, 32)...)
case []byte:
ret = append(ret, LeftPadBytes(t, 32)...)
}
}
return
}
func RightPadBytes(slice []byte, l int) []byte {
if l < len(slice) {
return slice
}
padded := make([]byte, l)
copy(padded[0:len(slice)], 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
}
func LeftPadString(str string, l int) string {
if l < len(str) {
return str
}
zeros := Bytes2Hex(make([]byte, (l-len(str))/2))
return zeros + str
}
func RightPadString(str string, l int) string {
if l < len(str) {
return str
}
zeros := Bytes2Hex(make([]byte, (l-len(str))/2))
return str + zeros
}
func ToAddress(slice []byte) (addr []byte) {
if len(slice) < 20 {
addr = LeftPadBytes(slice, 20)
} else if len(slice) > 20 {
addr = slice[len(slice)-20:]
} else {
addr = slice
}
addr = CopyBytes(addr)
return
}
func ByteSliceToInterface(slice [][]byte) (ret []interface{}) {
for _, i := range slice {
ret = append(ret, i)
}
return
}
