@evan: That's what I'm doing currently - serializing and writing the
bytestream for the magic, checksum and actual content messages
separately and in that order - I was just wondering if I could put
them all into one message { ... } and just serialize one message
instead of three.

- Srivats

On Mon, Jul 5, 2010 at 5:56 PM, Evan Jones <ev...@mit.edu> wrote:
> On Jul 5, 2010, at 7:25 , Srivats P wrote:
>> when a message is serialized its known fields should be written
>> sequentially by field number, as in the provided C++, Java, and Python
>> serialization code
>> </quote>
>> Like the encoded wire format, is the above guaranteed for the C++
>> Serialization API (assuming no unknown fields)?
> The "official" protobuf C++, Java, and Python implementations all write the
> fields out in tag number order (lowest to highest). However, their parsers
> handle messages where the fields are out of order.
>> I'm designing a file format based on protobuf. I plan to have the
>> first field as a fixed size file type magic value and second field as
>> a fixed size checksum value, followed by other fields. While opening
>> such a file, I'd like to match the magic value and verify the
>> checksum, before parsing the whole file.
> From this description, it doesn't sound like the field order matters?
> Serialize the protocol buffer, compute the checksum, then write out the
> (magic bytes)(checksum)(protocol buffer bytes)?
> Evan
> --
> Evan Jones
> http://evanjones.ca/

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