github.com/SmartMeshFoundation/Spectrum@v0.0.0-20220621030607-452a266fee1e/rlp/encoder_example_test.go (about)

     1  // Copyright 2014 The Spectrum Authors
     2  // This file is part of the Spectrum library.
     3  //
     4  // The Spectrum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The Spectrum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the Spectrum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package rlp
    18  
    19  import (
    20  	"fmt"
    21  	"io"
    22  )
    23  
    24  type MyCoolType struct {
    25  	Name string
    26  	a, b uint
    27  }
    28  
    29  // EncodeRLP writes x as RLP list [a, b] that omits the Name field.
    30  func (x *MyCoolType) EncodeRLP(w io.Writer) (err error) {
    31  	// Note: the receiver can be a nil pointer. This allows you to
    32  	// control the encoding of nil, but it also means that you have to
    33  	// check for a nil receiver.
    34  	if x == nil {
    35  		err = Encode(w, []uint{0, 0})
    36  	} else {
    37  		err = Encode(w, []uint{x.a, x.b})
    38  	}
    39  	return err
    40  }
    41  
    42  func ExampleEncoder() {
    43  	var t *MyCoolType // t is nil pointer to MyCoolType
    44  	bytes, _ := EncodeToBytes(t)
    45  	fmt.Printf("%v → %X\n", t, bytes)
    46  
    47  	t = &MyCoolType{Name: "foobar", a: 5, b: 6}
    48  	bytes, _ = EncodeToBytes(t)
    49  	fmt.Printf("%v → %X\n", t, bytes)
    50  
    51  	// Output:
    52  	// <nil> → C28080
    53  	// &{foobar 5 6} → C20506
    54  }