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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/decode.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/decode.c')
-rw-r--r-- | CAN-binder/libs/nanopb/examples/using_union_messages/decode.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/CAN-binder/libs/nanopb/examples/using_union_messages/decode.c b/CAN-binder/libs/nanopb/examples/using_union_messages/decode.c new file mode 100644 index 0000000..b9f4af5 --- /dev/null +++ b/CAN-binder/libs/nanopb/examples/using_union_messages/decode.c @@ -0,0 +1,96 @@ +/* This program reads a message from stdin, detects its type and decodes it. + */ + +#include <stdio.h> +#include <string.h> +#include <stdlib.h> + +#include <pb_decode.h> +#include "unionproto.pb.h" + +/* This function reads manually the first tag from the stream and finds the + * corresponding message type. It doesn't yet decode the actual message. + * + * Returns a pointer to the MsgType_fields array, as an identifier for the + * message type. Returns null if the tag is of unknown type or an error occurs. + */ +const pb_field_t* decode_unionmessage_type(pb_istream_t *stream) +{ + pb_wire_type_t wire_type; + uint32_t tag; + bool eof; + + while (pb_decode_tag(stream, &wire_type, &tag, &eof)) + { + if (wire_type == PB_WT_STRING) + { + const pb_field_t *field; + for (field = UnionMessage_fields; field->tag != 0; field++) + { + if (field->tag == tag && (field->type & PB_LTYPE_SUBMESSAGE)) + { + /* Found our field. */ + return field->ptr; + } + } + } + + /* Wasn't our field.. */ + pb_skip_field(stream, wire_type); + } + + return NULL; +} + +bool decode_unionmessage_contents(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct) +{ + pb_istream_t substream; + bool status; + if (!pb_make_string_substream(stream, &substream)) + return false; + + status = pb_decode(&substream, fields, dest_struct); + pb_close_string_substream(stream, &substream); + return status; +} + +int main() +{ + /* Read the data into buffer */ + uint8_t buffer[512]; + size_t count = fread(buffer, 1, sizeof(buffer), stdin); + pb_istream_t stream = pb_istream_from_buffer(buffer, count); + + const pb_field_t *type = decode_unionmessage_type(&stream); + bool status = false; + + if (type == MsgType1_fields) + { + MsgType1 msg = {}; + status = decode_unionmessage_contents(&stream, MsgType1_fields, &msg); + printf("Got MsgType1: %d\n", msg.value); + } + else if (type == MsgType2_fields) + { + MsgType2 msg = {}; + status = decode_unionmessage_contents(&stream, MsgType2_fields, &msg); + printf("Got MsgType2: %s\n", msg.value ? "true" : "false"); + } + else if (type == MsgType3_fields) + { + MsgType3 msg = {}; + status = decode_unionmessage_contents(&stream, MsgType3_fields, &msg); + printf("Got MsgType3: %d %d\n", msg.value1, msg.value2); + } + + if (!status) + { + printf("Decode failed: %s\n", PB_GET_ERROR(&stream)); + return 1; + } + + return 0; +} + + + |