Re: [protobuf] Help with basic concepts of descriptors and reflection
On Jul 15, 2010, at 16:40 , mark.t.macdon...@googlemail.com wrote: coutMessage1.name(); coutMessage1.GetReflection()-GetString( ref, stabiliser.GetDescriptor()-FindFieldByName(name)); The differences between these two are HUGE. The first one is a compiled local variable reference (effectively). The second has to do some sort of table lookup. You want to use the first form if you care about performance. Evan -- Evan Jones 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 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.
[protobuf] Help with basic concepts of descriptors and reflection
1. Is there anything incorrect in my understanding so far?: * Descriptors = INTROSPECTION (querying the message structure at runtime) * Reflection = Introspection + MODIFYING the message structure at runtime * Descriptors and Reflection are implemented as C++ structures with member functions * These structures are shared by all instances of the same message class If so, I would be interested to know how several message objects can share the same structure (underlying implementation). 2. Both the lines below print the value of the name field in Message1. Are there big performance or other differences between how each method gets the value? Message Message1; Message ref=Message1; //reference to message1 coutMessage1.name(); coutMessage1.GetReflection()-GetString( ref, stabiliser.GetDescriptor()-FindFieldByName(name)); Thanks! -- 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.
