Imported Upstream version 1.4upstream/1.4

1 files changed, 61 insertions, 0 deletions

diff --git a/src/encoding/gob/example_encdec_test.go b/src/encoding/gob/example_encdec_test.go
new file mode 100644
index 000000000..e45ad4ccf
--- /dev/null
+++ b/src/encoding/gob/example_encdec_test.go
@@ -0,0 +1,61 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob_test
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+	"log"
+)
+
+// The Vector type has unexported fields, which the package cannot access.
+// We therefore write a BinaryMarshal/BinaryUnmarshal method pair to allow us
+// to send and receive the type with the gob package. These interfaces are
+// defined in the "encoding" package.
+// We could equivalently use the locally defined GobEncode/GobDecoder
+// interfaces.
+type Vector struct {
+	x, y, z int
+}
+
+func (v Vector) MarshalBinary() ([]byte, error) {
+	// A simple encoding: plain text.
+	var b bytes.Buffer
+	fmt.Fprintln(&b, v.x, v.y, v.z)
+	return b.Bytes(), nil
+}
+
+// UnmarshalBinary modifies the receiver so it must take a pointer receiver.
+func (v *Vector) UnmarshalBinary(data []byte) error {
+	// A simple encoding: plain text.
+	b := bytes.NewBuffer(data)
+	_, err := fmt.Fscanln(b, &v.x, &v.y, &v.z)
+	return err
+}
+
+// This example transmits a value that implements the custom encoding and decoding methods.
+func Example_encodeDecode() {
+	var network bytes.Buffer // Stand-in for the network.
+
+	// Create an encoder and send a value.
+	enc := gob.NewEncoder(&network)
+	err := enc.Encode(Vector{3, 4, 5})
+	if err != nil {
+		log.Fatal("encode:", err)
+	}
+
+	// Create a decoder and receive a value.
+	dec := gob.NewDecoder(&network)
+	var v Vector
+	err = dec.Decode(&v)
+	if err != nil {
+		log.Fatal("decode:", err)
+	}
+	fmt.Println(v)
+
+	// Output:
+	// {3 4 5}
+}