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package ethutil
import (
"bytes"
"encoding/binary"
"fmt"
)
// 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(reader *bytes.Reader) (ret uint64) {
if reader.Len() == 8 {
var num uint64
binary.Read(reader, binary.BigEndian, &num)
ret = uint64(num)
} else if reader.Len() == 4 {
var num uint32
binary.Read(reader, binary.BigEndian, &num)
ret = uint64(num)
} else if reader.Len() == 2 {
var num uint16
binary.Read(reader, binary.BigEndian, &num)
ret = uint64(num)
} else {
var num uint8
binary.Read(reader, binary.BigEndian, &num)
ret = uint64(num)
}
return ret
}
// 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)
}
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