2010/10/30 ZHOU Xiaobo <xb.z...@qq.com> > A further question: > Can ProtoBuf do in-place deserialization? >
Not at present, no. > > Say I have a packet including a COMMAND field and a big DATA field, and > I should only deserialize this packet to read COMMAND to decide how to > process DATA. > The question is: does ProtoBuf copy DATA field when deserializing, and can > I avoid that? > > > ----- Original Message ----- > From: "Henner Zeller" <henner.zel...@googlemail.com> > To: "Ashwin Jayaprakash" <ashwin.jayaprak...@gmail.com> > Cc: "Protocol Buffers" <protobuf@googlegroups.com> > Sent: 2010年 10 月 30日, 星期六 上午 8:19:02 GMT +08:00 Beijing / Chongqing / Hong > Kong / Urumqi > Subject: Re: [protobuf] Read selective fields without deserializing the > entire object? > > On Fri, Oct 29, 2010 at 16:13, Ashwin Jayaprakash > <ashwin.jayaprak...@gmail.com> wrote: > > Is there a way to read selective fields without deserializing the > > entire object? > > > > My serialized message is stored in memory as a (Heap)ByteBuffer. > > > > I'm trying to find out if any of the (de-)serialization frameworks > > allow a way to read specific fields without having to deserialize the > > entire message. The message has almost 200 fields - mostly Strings and > > a few long and int fields. Deserialization is expensive and creates > > too much garbage considering the fact that I just need to read 1-2 > > fields. > > The fields are not 'indexed' in the beginning of the message so that > it is not simple to just jump to a particular field. > > What you can do is to direclty use the CodedInputStream to parse > through the message, tag by tag and only read the tags you are > interested in. As soon as you have all fields together, you can stop > reading. So it is a bit manual work involved. > Also, if you want to be faster and skip bigger parts of the message, > make sure to create sub-messages within that message, maybe there is a > logical grouping of your fields ? You can skip a sub-message at once > if you don't need it instead of iterating through all fields in it, > which is faster. > > H. > > > > > > > Thanks in advance. > > > > -- > > 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<protobuf%2bunsubscr...@googlegroups.com> > . > > For more options, visit this group at > http://groups.google.com/group/protobuf?hl=en. > > > > > > -- > 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<protobuf%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/protobuf?hl=en. > > > > > -- > 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<protobuf%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/protobuf?hl=en. > > -- 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.
