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author | 2017-05-19 16:20:02 +0200 | |
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committer | 2017-05-19 16:20:02 +0200 | |
commit | 2d574dc77f68ecb5150016989900860e8b74be50 (patch) | |
tree | d691a8345a58dcd080131c58d028f77df51a45ed /CAN-binder/libs/nanopb/examples/using_union_messages/encode.c | |
parent | 48a2605965af1f05ba7f01f6e8c1758a4c9b0522 (diff) | |
parent | 278ffb890e3d8722e4c7d824baaf221a1e375fc4 (diff) |
Add 'CAN-binder/libs/nanopb/' from commit '278ffb890e3d8722e4c7d824baaf221a1e375fc4'
git-subtree-dir: CAN-binder/libs/nanopb
git-subtree-mainline: 48a2605965af1f05ba7f01f6e8c1758a4c9b0522
git-subtree-split: 278ffb890e3d8722e4c7d824baaf221a1e375fc4
Diffstat (limited to 'CAN-binder/libs/nanopb/examples/using_union_messages/encode.c')
-rw-r--r-- | CAN-binder/libs/nanopb/examples/using_union_messages/encode.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/CAN-binder/libs/nanopb/examples/using_union_messages/encode.c b/CAN-binder/libs/nanopb/examples/using_union_messages/encode.c new file mode 100644 index 0000000..e124bf9 --- /dev/null +++ b/CAN-binder/libs/nanopb/examples/using_union_messages/encode.c @@ -0,0 +1,85 @@ +/* This program takes a command line argument and encodes a message in + * one of MsgType1, MsgType2 or MsgType3. + */ + +#include <stdio.h> +#include <string.h> +#include <stdlib.h> + +#include <pb_encode.h> +#include "unionproto.pb.h" + +/* This function is the core of the union encoding process. It handles + * the top-level pb_field_t array manually, in order to encode a correct + * field tag before the message. The pointer to MsgType_fields array is + * used as an unique identifier for the message type. + */ +bool encode_unionmessage(pb_ostream_t *stream, const pb_field_t messagetype[], const void *message) +{ + const pb_field_t *field; + for (field = UnionMessage_fields; field->tag != 0; field++) + { + if (field->ptr == messagetype) + { + /* This is our field, encode the message using it. */ + if (!pb_encode_tag_for_field(stream, field)) + return false; + + return pb_encode_submessage(stream, messagetype, message); + } + } + + /* Didn't find the field for messagetype */ + return false; +} + +int main(int argc, char **argv) +{ + if (argc != 2) + { + fprintf(stderr, "Usage: %s (1|2|3)\n", argv[0]); + return 1; + } + + uint8_t buffer[512]; + pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer)); + + bool status = false; + int msgtype = atoi(argv[1]); + if (msgtype == 1) + { + /* Send message of type 1 */ + MsgType1 msg = {42}; + status = encode_unionmessage(&stream, MsgType1_fields, &msg); + } + else if (msgtype == 2) + { + /* Send message of type 2 */ + MsgType2 msg = {true}; + status = encode_unionmessage(&stream, MsgType2_fields, &msg); + } + else if (msgtype == 3) + { + /* Send message of type 3 */ + MsgType3 msg = {3, 1415}; + status = encode_unionmessage(&stream, MsgType3_fields, &msg); + } + else + { + fprintf(stderr, "Unknown message type: %d\n", msgtype); + return 2; + } + + if (!status) + { + fprintf(stderr, "Encoding failed!\n"); + return 3; + } + else + { + fwrite(buffer, 1, stream.bytes_written, stdout); + return 0; /* Success */ + } +} + + |