On Wed, Dec 17, 2008 at 4:03 PM, Ryan <ryanroll...@gmail.com> wrote:
> Funny, ParseFromArray gets the right message length when passed a
> buffer 0 padded at the end.
Odd, it should fail (return false) in this case.
>
>
> Thanks
>
> On Dec 17, 12:45 pm, Kenton Varda <ken...@google.com> wrote:
> > When you call ParseFromArray(), you must pass the exact size of the
> message
> > being parsed. You cannot simply give it the size of the buffer if there
> are
> > extra bytes after the end of the message.
> > What happened here is that the parser, after parsing the bytes of your
> > actual message, continued to interpret the following bytes as more data.
> > The next byte was a 1, which the parser thought was indicating the
> > beginning of a 64-bit fixed-width field with field number zero. Since
> your
> > message does not declare a field number zero (you actually aren't allowed
> > to), it treated this as an unknown field and stored the value in the
> > UnknownFieldSet. Later, when you serialized the message, the value in
> the
> > UnknownFieldSet was written out again.
> >
> > The moral of the story is that you must transmit the size of your message
> > along with the data, so that you can pass it to ParseFromArray() on the
> > receiving end.
> >
> > On Wed, Dec 17, 2008 at 2:22 PM, Ryan <ryanroll...@gmail.com> wrote:
> >
> > > Ok - found it. The problem was not on the serialization but on the
> > > message creation/parsing. The buffer the C++ code was parsing the
> > > protocol buffer message from was not properly initialized causing the
> > > ByteSize() function to return an incorrect value based on the junk
> > > padded past the typical sentinel.
> >
> > > I did a call to memset prior and all is good.
> >
> > > Two additional thoughts:
> >
> > > 1) I am surprised the C++ parsing succeeded?
> >
> > > 2) Why was the serialization reproducing the bad input? I would think
> > > the process of Marshalling/Unmarshalling would of cleaned it up.
> >
> > > On Dec 17, 10:48 am, Ryan <ryanroll...@gmail.com> wrote:
> > > > I will try. A good debugging step for myself if not anything else.
> > > > This system is of course distributed so it may be difficult to
> isolate
> > > > it down into something I can send you easily (also lots of
> > > > dependencies). I have been trying to identify the messages that are
> > > > causing this but it appears to be happening independent of the
> message
> > > > contents.
> >
> > > > In a particular sequence of messages the same messages always get the
> > > > erroneous bytes appended. However, if I take one of those messages
> and
> > > > send it independently - works fine.
> >
> > > > Weird...
> >
> > > > Thanks for the dialog.
> >
> > > > On Dec 17, 9:36 am, Kenton Varda <ken...@google.com> wrote:
> >
> > > > > If you write a program demonstrating the problem and send it to me,
> I
> > > can
> > > > > debug it.
> >
> > > > > On Wed, Dec 17, 2008 at 11:10 AM, Ryan <ryanroll...@gmail.com>
> wrote:
> >
> > > > > > char mess[MAX_MESSLEN] ;
> > > > > > .
> > > > > > //Load some properties for the group com call
> > > > > > .
> > > > > > .
> > > > > > bplMessage.SerializeToArray(mess,bplMessage.ByteSize());
> >
> > > > > > //what I am using to detect trailing bytes
> > > > > > for(int i =0; i< bplMessage.ByteSize();i++) {
> > > > > > std::cout << (int) mess[i] << std::endl;
> > > > > > }
> >
> > > > > > On Dec 17, 8:32 am, Kenton Varda <ken...@google.com> wrote:
> > > > > > > Hi Ryan,
> > > > > > > What does your code look like that calls SerializeToArray()?
> It
> > > should
> > > > > > be
> > > > > > > something like:
> >
> > > > > > > int size = message.ByteSize();
> > > > > > > char* array = new char[size];
> > > > > > > message.SerializeToArray(array, size);
> >
> > > > > > > On Tue, Dec 16, 2008 at 8:13 PM, Ryan <ryanroll...@gmail.com>
> > > wrote:
> >
> > > > > > > > I have been working with a Group Communication System and
> > > Protocol
> > > > > > > > Buffers.
> >
> > > > > > > > I have an issue where the C++ SerializeToArray call on one of
> my
> > > > > > > > messages is occasionally appending Bytes {1,0,0,0,0,0,0,0,0}
> to
> > > the
> > > > > > > > end of the returned character array?
> >
> > > > > > > > Any ideas on what might be causing this? I can
> > > Marshall/Unmarshall
> > > > > > > > fine using the java api but the C++ call above has the odd
> quirk
> > > > > > > > mentioned.
> >
> > > > > > > > The Java parsingFrom fails on the C++ generated messages that
> > > have the
> > > > > > > > above bytes appended.
> >
> > > > > > > > Any suggestions much appreciated.
> >
>
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