package encoding/binary
Size returns how many bytes Write would generate to encode the value v (1st parameter), which must be a fixed-size value or a slice of fixed-size values, or a pointer to such data.
Golang encoding/binary.Size() function usage examples
Example 1 :
package main
import (
"encoding/binary"
"fmt"
)
func main() {
var a int
b := [6]int64{1}
fmt.Println(binary.Size(a))
fmt.Println(binary.Size(b))
}
Output :
-1
64
Example 2 :
func binaryRead(r io.Reader, order binary.ByteOrder, data interface{}) (n int64, err error) {
var read int
buf := make([]byte, binary.Size(data)) // <--- binary.Size()
if read, err = io.ReadFull(r, buf); err != nil {
return int64(read), err
}
return int64(read), binary.Read(bytes.NewBuffer(buf), order, data)
}
References :
http://golang.org/pkg/encoding/binary/#Size
https://github.com/conformal/btcwallet/blob/master/keystore/keystore.go
