On Wed, Oct 20, 2010 at 3:28 AM, Paul <mjpabl...@gmail.com> wrote: > Hi, > > I am sending messages from a C++ client to a Java server, but I am > wondering about the length of the buffer I am using to send it over. > This is the C++ code: > > CLIENT SIDE CODE: > *** the protocol buffers message is called snap1 *** > > int numBytesForDelim = sizeof(int); > char *snap_buf2; > snap_buf2 = new char[snap1.ByteSize() + 100]; > > ZeroCopyOutputStream* raw_output = new ArrayOutputStream(snap_buf2, > snap1.ByteSize()+numBytesForDelim); > CodedOutputStream* coded_output = new > CodedOutputStream(raw_output); > > coded_output->WriteVarint32(snap1.ByteSize()); > snap1.SerializeToCodedStream(coded_output); > > delete coded_output; > delete raw_output; > > send(socket, snap_buf2, snap1.ByteSize()+numBytesForDelim/2, 0); // > send over a socket > delete [] snap_buf2; > snap_buf2 = NULL; > > When I send this over to the Java server side, the Java code uses > "parseDelimitedFrom" to parse the data. however, I am not sure why > when I call send, the length of the message has to be snap1.ByteSize() > +numBytesForDelim/2 rather than snap1.ByteSize()+numBytesForDelim. I > would think that it would be the latter, but when I try it, I get > exceptions on the Java side saying that the protocol message has not > filled out all the fields. For some reason, it is necessary for me to > cut off the last two bytes when sending over TCP. Any ideas as to why > this is?
I dont know this in detail, but in my experience with java and c++ i needed swap the two bytes before the buffer containing the length. the length of the buffer is sent before the buffer from java to c++ using the java byte order. I dont know if this applies, but you should print out the first two bytes and try swapping them. Look up my old messages or code for details. mike -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to proto...@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
