[protobuf] Re: Serializing part of a message and writing to disk
Thank you for the response. On Mar 8, 5:59 am, Evan Jones ev...@mit.edu wrote: On Mar 8, 2011, at 2:12 , Linus wrote: At a later stage in the code, the values of (say) Message A are changed by the user. Is there a way of modifying only Message A and updating the file on disk, without loading the composite Message C updating the Message A and flushing entire contents to disk again? Not really: protocol buffers are a variable length encoding, so changing Message A could change the length, so overwriting doesn't really work, at least not without additional checks and effort. Evan --http://evanjones.ca/ -- You received this message because you are subscribed to the Google Groups Protocol Buffers group. To post to this group, send email to protobuf@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.
[protobuf] Serializing part of a message and writing to disk
I have a composite message, meaning Message C is composed of Message
A and Message B.
Message C
{
required Message A = 1;
required Message B = 2;
}
This composite message C I have serialized to disk ( say output.dat).
At a later stage in the code, the values of (say) Message A are
changed by the user. Is there a way of modifying only Message A and
updating the file on disk, without loading the composite Message C
updating the Message A and flushing entire contents to disk again?
Any help appreciated.
Thanks,
Linus
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[protobuf] Re: Chunking a large message
Thanks Evan. Your response makes some things clear to me. I meant to say I'd like chunks of 1MB ( I re-read my email and realize it wasn't worded properly). I now have some ideas that I'm going to try out. Thanks again! On Mar 4, 8:37 am, Evan Jones ev...@mit.edu wrote: On Mar 3, 2011, at 15:53 , Linus wrote: I am wondering if there are any examples of chunking large PB messages (about 1MB) into smaller chunks, to transmit over the wire. This is going to be pretty application specific. Typically it involves taking one message with a huge repeated field and sending it / writing it as a sequence of messages with fewer items for each repeated field. So I can't really point you to any examples off the top of my head. That said: the documentation suggests keeping protocol buffers to be ~ 1 MB in size, so if your messages are 1 MB, I personally wouldn't worry about it. Hope this helps, Evan --http://evanjones.ca/ -- You received this message because you are subscribed to the Google Groups Protocol Buffers group. To post to this group, send email to protobuf@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.
[protobuf] Chunking a large message
Hello, I am wondering if there are any examples of chunking large PB messages (about 1MB) into smaller chunks, to transmit over the wire. Thanks, Linus -- You received this message because you are subscribed to the Google Groups Protocol Buffers group. To post to this group, send email to protobuf@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.
[protobuf] Nested messages using C++
Hello,
I have nested messages like the following (it is a little more
complicated, but i am trying to simplify with this example).
package DB;
message Header
{
required int32 ID=1;
message param
{
required int32 size_m = 1;
required int32 size_n = 2;
}
required param p = 2;
}
message data
{
repeated double = 1;
}
message DB
{
required Header = 1;
required data = 2;
}
The problem I am having is that the accessor methods generated for the
DB does not have a
set_param( DB::Header::param ).
Is there something wrong with how I am structuring my messages? Any
help is appreciated.
Please let me know if this post is unclear and I will try and explain
myself better.
Thanks!
Linus
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[protobuf] Re: Nested messages using C++
I am new to PB and I just ran into this. Is it possible that the PB
compiler does not generate set_... methods for some nested messages?
Here is an example: I don't see set_... methods for ANY of the
parameters in the db message.
What am I missing???
package pd;
message nv
{
repeated int32 Length = 1;
}
message dp
{
required int32 DesignID = 1;
repeated double Design = 2;
}
message Shape
{
required int32 size_m = 1;
required int32 size_n = 2;
}
message ds
{
required int32 DesignID = 1;
repeated double data = 2;
}
message db
{
required nv numVars = 1;
repeated dp despar = 2;
required Shape db_size = 3;
repeated ds dtst = 4;
}
On Jan 13, 1:48 pm, Linus suram.su...@gmail.com wrote:
Hello,
I have nested messages like the following (it is a little more
complicated, but i am trying to simplify with this example).
package DB;
message Header
{
required int32 ID=1;
message param
{
required int32 size_m = 1;
required int32 size_n = 2;
}
required param p = 2;
}
message data
{
repeated double = 1;
}
message DB
{
required Header = 1;
required data = 2;
}
The problem I am having is that the accessor methods generated for the
DB does not have a
set_param( DB::Header::param ).
Is there something wrong with how I am structuring my messages? Any
help is appreciated.
Please let me know if this post is unclear and I will try and explain
myself better.
Thanks!
Linus
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[protobuf] Re: Nested messages using C++
Cool!
Thank you for the clarification.
On Jan 13, 5:44 pm, Jason Hsueh jas...@google.com wrote:
By the way this is documented
here:http://code.google.com/apis/protocolbuffers/docs/reference/cpp-genera...
On Thu, Jan 13, 2011 at 5:42 PM, Jason Hsueh jas...@google.com wrote:
On Thu, Jan 13, 2011 at 5:38 PM, Linus suram.su...@gmail.com wrote:
I am new to PB and I just ran into this. Is it possible that the PB
compiler does not generate set_... methods for some nested messages?
Here is an example: I don't see set_... methods for ANY of the
parameters in the db message.
For message type fields, there is no set_... method. The codegen produces
mutable_... methods instead. Otherwise it is easy to write inefficient
code - set would require a potentially expensive copy of the message.
What am I missing???
package pd;
message nv
{
repeated int32 Length = 1;
}
message dp
{
required int32 DesignID = 1;
repeated double Design = 2;
}
message Shape
{
required int32 size_m = 1;
required int32 size_n = 2;
}
message ds
{
required int32 DesignID = 1;
repeated double data = 2;
}
message db
{
required nv numVars = 1;
repeated dp despar = 2;
required Shape db_size = 3;
repeated ds dtst = 4;
}
On Jan 13, 1:48 pm, Linus suram.su...@gmail.com wrote:
Hello,
I have nested messages like the following (it is a little more
complicated, but i am trying to simplify with this example).
package DB;
message Header
{
required int32 ID=1;
message param
{
required int32 size_m = 1;
required int32 size_n = 2;
}
required param p = 2;
}
message data
{
repeated double = 1;
}
message DB
{
required Header = 1;
required data = 2;
}
The problem I am having is that the accessor methods generated for the
DB does not have a
set_param( DB::Header::param ).
Is there something wrong with how I am structuring my messages? Any
help is appreciated.
Please let me know if this post is unclear and I will try and explain
myself better.
Thanks!
Linus
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.
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