1 /* This program takes a command line argument and encodes a message in
2 * one of MsgType1, MsgType2 or MsgType3.
3 */
4
5 #include <stdio.h>
6 #include <string.h>
7 #include <stdlib.h>
8
9 #include <pb_encode.h>
10 #include <pb_common.h>
11 #include "unionproto.pb.h"
12
13 /* This function is the core of the union encoding process. It handles
14 * the top-level pb_field_t array manually, in order to encode a correct
15 * field tag before the message. The pointer to MsgType_fields array is
16 * used as an unique identifier for the message type.
17 */
encode_unionmessage(pb_ostream_t * stream,const pb_msgdesc_t * messagetype,void * message)18 bool encode_unionmessage(pb_ostream_t *stream, const pb_msgdesc_t *messagetype, void *message)
19 {
20 pb_field_iter_t iter;
21
22 if (!pb_field_iter_begin(&iter, UnionMessage_fields, message))
23 return false;
24
25 do
26 {
27 if (iter.submsg_desc == messagetype)
28 {
29 /* This is our field, encode the message using it. */
30 if (!pb_encode_tag_for_field(stream, &iter))
31 return false;
32
33 return pb_encode_submessage(stream, messagetype, message);
34 }
35 } while (pb_field_iter_next(&iter));
36
37 /* Didn't find the field for messagetype */
38 return false;
39 }
40
main(int argc,char ** argv)41 int main(int argc, char **argv)
42 {
43 if (argc != 2)
44 {
45 fprintf(stderr, "Usage: %s (1|2|3)\n", argv[0]);
46 return 1;
47 }
48
49 uint8_t buffer[512];
50 pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer));
51
52 bool status = false;
53 int msgtype = atoi(argv[1]);
54 if (msgtype == 1)
55 {
56 /* Send message of type 1 */
57 MsgType1 msg = {42};
58 status = encode_unionmessage(&stream, MsgType1_fields, &msg);
59 }
60 else if (msgtype == 2)
61 {
62 /* Send message of type 2 */
63 MsgType2 msg = {true};
64 status = encode_unionmessage(&stream, MsgType2_fields, &msg);
65 }
66 else if (msgtype == 3)
67 {
68 /* Send message of type 3 */
69 MsgType3 msg = {3, 1415};
70 status = encode_unionmessage(&stream, MsgType3_fields, &msg);
71 }
72 else
73 {
74 fprintf(stderr, "Unknown message type: %d\n", msgtype);
75 return 2;
76 }
77
78 if (!status)
79 {
80 fprintf(stderr, "Encoding failed!\n");
81 return 3;
82 }
83 else
84 {
85 fwrite(buffer, 1, stream.bytes_written, stdout);
86 return 0; /* Success */
87 }
88 }
89
90
91
