According to the example code https://developers.google.com/protocol-buffers/docs/cpptutorial, they show how to parse in a proto file that is in binary format. using
tutorial::AddressBook address_book;
{
// Read the existing address book.
fstream input(argv[1], ios::in | ios::binary);
if (!address_book.ParseFromIstream(&input)) {
cerr << "Failed to parse address book." << endl;
return -1;
}
}
I tried removing the ios::binary
for my input file that is in text format, but that still fails at reading in the file. What do I need to do to read in a proto file in text format?
Protobuf is a binary format, so reading and writing should be done as binary, not text. If you don't want binary format, you should consider using something other than protobuf (there are lots of textual data formats, such as XML, JSON, CSV); just using text abstractions is not enough.
Protocol buffers are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data – think XML, but smaller, faster, and simpler.
Protocol buffers messages always use little-endian encoding. Implementations running on big-endian architectures should be doing the conversions automatically. If you are receiving data in wrong order, I would suggest using protoc --decode_raw to see whether the error occurs on the transmission or reception side.
Alright, I got this figured out. To read in a text proto file into an object....
#include <iostream>
#include <fcntl.h>
#include <fstream>
#include <google/protobuf/text_format.h>
#include <google/protobuf/io/zero_copy_stream_impl.h>
#include "YourProtoFile.pb.h"
using namespace std;
int main(int argc, char* argv[])
{
// Verify that the version of the library that we linked against is
// compatible with the version of the headers we compiled against.
GOOGLE_PROTOBUF_VERIFY_VERSION;
Tasking *tasking = new Tasking(); //My protobuf object
bool retValue = false;
int fileDescriptor = open(argv[1], O_RDONLY);
if( fileDescriptor < 0 )
{
std::cerr << " Error opening the file " << std::endl;
return false;
}
google::protobuf::io::FileInputStream fileInput(fileDescriptor);
fileInput.SetCloseOnDelete( true );
if (!google::protobuf::TextFormat::Parse(&fileInput, tasking))
{
cerr << std::endl << "Failed to parse file!" << endl;
return -1;
}
else
{
retValue = true;
cerr << "Read Input File - " << argv[1] << endl;
}
cerr << "Id -" << tasking->taskid() << endl;
}
My program takes in the input file for the proto buff as the first parameter when i execute it at the terminal. For example ./myProg inputFile.txt
Hope this helps anyone with the same question
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With