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package ethutil
import (
"bytes"
"encoding/binary"
"encoding/hex"
"fmt"
"math/big"
"strings"
)
// 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
}
// Binary length
//
// Returns the true binary length of the given number
func BinaryLength(num int) int {
if num == 0 {
return 0
}
return 1 + BinaryLength(num>>8)
}
// 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 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 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 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 Address(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
}
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