go-ethereum/rlp/encoder_example_test.go

55 lines
1.6 KiB
Go

// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// go-ethereum 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 rlp
import (
"fmt"
"io"
)
type MyCoolType struct {
Name string
a, b uint
}
// EncodeRLP writes x as RLP list [a, b] that omits the Name field.
func (x *MyCoolType) EncodeRLP(w io.Writer) (err error) {
// Note: the receiver can be a nil pointer. This allows you to
// control the encoding of nil, but it also means that you have to
// check for a nil receiver.
if x == nil {
err = Encode(w, []uint{0, 0})
} else {
err = Encode(w, []uint{x.a, x.b})
}
return err
}
func ExampleEncoder() {
var t *MyCoolType // t is nil pointer to MyCoolType
bytes, _ := EncodeToBytes(t)
fmt.Printf("%v → %X\n", t, bytes)
t = &MyCoolType{Name: "foobar", a: 5, b: 6}
bytes, _ = EncodeToBytes(t)
fmt.Printf("%v → %X\n", t, bytes)
// Output:
// <nil> → C28080
// &{foobar 5 6} → C20506
}