1 files changed, 63 insertions, 0 deletions
diff --git a/examples/cmd/union-example/union_example.go b/examples/cmd/union-example/union_example.go
new file mode 100644
index 0000000..bb6c8a1
--- /dev/null
+++ b/examples/cmd/union-example/union_example.go
@@ -0,0 +1,63 @@
+// Copyright (c) 2018 Cisco and/or its affiliates.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// union-example is an example to show how to use unions in VPP binary API.
+package main
+
+import (
+	"bytes"
+	"log"
+
+	"git.fd.io/govpp.git/examples/bin_api/ip"
+	"github.com/lunixbochs/struc"
+)
+
+func main() {
+	// create union with IPv4 address
+	var unionIP4 ip.AddressUnion
+	unionIP4.SetIP4(ip.IP4Address{Address: []byte{192, 168, 1, 10}})
+
+	// use it in the Address type
+	addr := &ip.Address{
+		Af: ip.ADDRESS_IP4,
+		Un: unionIP4,
+	}
+	log.Printf("encoding union IPv4: %v", addr.Un.GetIP4())
+
+	// encode the address with union
+	data := encode(addr)
+	// decode the address with union
+	addr2 := decode(data)
+
+	log.Printf("decoded union IPv4: %v", addr2.Un.GetIP4())
+}
+
+func encode(addr *ip.Address) []byte {
+	log.Printf("encoding address: %#v", addr)
+	buf := new(bytes.Buffer)
+	if err := struc.Pack(buf, addr); err != nil {
+		panic(err)
+	}
+	return buf.Bytes()
+}
+
+func decode(data []byte) *ip.Address {
+	addr := new(ip.Address)
+	buf := bytes.NewReader(data)
+	if err := struc.Unpack(buf, addr); err != nil {
+		panic(err)
+	}
+	log.Printf("decoded address: %#v", addr)
+	return addr
+}