I have C code written in proto2 format and compiled by the protoc-c compiler. What I would like to know is whether that code is binary compatible with serialization/de-serialization code generated by the 'protoc' compiler (that also happens to understand version 3 of protobuf)? For some reason I am not able to get a definitive answer to this question. The reason I am wondering is because there are already backwards compatibility issues between version 3 and version 2, so I am a little uncertain with the protoc-c and protoc toolkits and how they handle versions.
Thanks!
Yes, these two implementations should be compatible--you can serialize messages with one implementation and successfully parse them with another. I have not personally tried protobuf-c but based on its description it is just another implementation of the same protocol buffer wire format.
You mentioned differences between syntax = "proto2" and syntax = "proto3". It is true that these are different and you would have to be careful if you want to migrate from one to the other, but I think this issue is orthogonal to your question about compatibility between protobuf-c and Google's protobuf implementation.
Related
The ComplexExpr and ComplexFunc classes in the links below seem very convenient to work with complex numbers. Is there a plan to include them into the official Halide API? Or is there a reason why they are not included?
https://github.com/halide/Halide/blob/master/apps/fft/complex.h
https://github.com/halide/Halide/blob/be1269b15f4ba8b83df5fa0ef1ae507017fe1a69/apps/fft/funct.h
Speaking as a Halide developer...
Or is there a reason why they are not included?
We haven't included these historically since we didn't want to bless a particular representation for complex numbers. There are a few valid ways of dealing with them and the headers in question are just one.
Is there a plan to include them into the official Halide API?
We've started talking about packaging some of this type of code into a set of header-only "Halide tools" libraries, so named to avoid the normative implication of calling it something like "stdlib". So as of right now, there is no concrete plan, but the odds are nonzero.
In the meantime, the code is MIT licensed, so you should feel free to use those files, regardless.
I am new to Protobufs; I haven't had much exposure to them. One of the API endpoints we require data from, uses Protobuf encoded data. This generally wouldn't be an issue if I was using a 'supported' language such as JavaScript, Java, Python or even R to decode the data...
Unfortunately, I am trying to automate the process using Alteryx. Rather than this being an Alteryx specific question, I have a few questions about Protobufs themselves so I understand this situation better. I've read through the implementation of Protobufs in Java and Python, and have a basic understanding of how to use them.
To surmise (please correct me if I am wrong), a Protobuf is a method of serializing structured data where a .proto schema is used to encode / decode data into raw binary. My confusion lies with the compiler. Google documentation and examples for Python / Java show how a Protobuf compiler (library) is required in order to run the encoding and decoding process. Reading the Google website, it advises that the Protobufs are 'language neutral and platform neutral', but I can't see how that is possible if you need the compiler (and .proto file!) to do the decoding. For example, how would anyone using a language outside of the languages where Google have a compiler created possibly decode Protobuf encoded data? Am I missing something?
I figure I'm missing something, since it seems weird that a public API would force this constraint.
"language/platform neutral" here simply means that you can reliably get the same data back from any language/framework/platform. The serialization format is defined independently and does not rely on the nuances of any particular framework.
This might seem a low bar, but you'd be surprised how many serialization formats fail to clear it.
Because the format is specified, anyone can create a tool for some other platform. It is a little fiddly if you're not used to dealing in bits, but: totally doable. The protobuf landscape is not dependent on Google - here's a list of some of the known non-Google tools: https://github.com/protocolbuffers/protobuf/blob/master/docs/third_party.md
Also, note that technically you don't even need a .proto; you just need some mechanism for specifying which fields map to which field numbers (since protobuf doesn't include the names). Quite a few in that list can work either from a .proto, or from the field/number map being specified in some other way. The advantage of .proto is simply that it is easy to convey as the schema - and again: isn't tied to any particular language. You can write plugins for "protoc" to add your own tooling, so you don't need to write your own parser from scratch. Or you can write your own parser from scratch if you prefer.
You can't speak of non-supported platform in this case: it is more about languages for which you can't find a protobuf implementation.
My 2 cents is: if you can't find a protobuf implementation for your language, find another language you're familiar with (and popular in protobuf community) and handle the protobuf serialization/deserialization with it. Then call it via a REST API, a executable ... whatever
I'm creating a VHDL project (Xilinx ISE for Spartan-6) that will be required to use decimal "real-style" numbers in either fixed/floating point (I'm hoping fixed point will be sufficient).
Being quite new to VHDL, I found out the hard way that the non-constant real types are not supported for synthesis, so I set about searching for a IP core or library to redress this.
So far I've found 3 options;
1) A floating point IP core provided by Xilinx
2) A downloadable "ieee_proposed" library written by a David Bishop found here
3) After spending a fair while attempting to work out how to "create" a new library with David Bishops files in, I took a quick look through the default IEEE library and saw it contains ieee.fixed_generic_pkg and ieee.fixed_pkg packages.
My question is - of the two libraries - which one would be sensible to use? Is one adapted for synthesis and one not, or one older than the other? And then if floating point is provided, is there any real point to the floating point IP core provided by Xilinx?
I've trawled through many questions of people attempting to add the ieee_proposed libraries, but none seem to have referenced the fact they they already seem to exist in the existing IEEE.
Thanks very much for any help!
============UPDATE (Essentially my own efforts to resolve)==================
I can't actually use the ieee.fixed_pkg - and attempting to do so gives me the error Cannot find <fixed_pkg> in library <ieee>.
After finding the ieee library at C:\Xilinx\14.7\ISE_DS\ISE\vhdl\xst\nt I've found that the fixed_pkg actually resides in ieee_proposed. However, this still throws up the same errors!
Dumb question, but when you downloaded the ieee_proposed did you also remember to compile it?
edit: And also remember to map the library to you simulation as well. Maybe you did all this already but these are the mistakes I make often.
I've been battling with the same problems for days.
The way I solved it is:
1. Add fixed_float_types_c, fixed_pkg_c and float_pkg_c vhdl files to project.
2. Declare them as belonging to work library (Properties in Quartus files window)
3. Compile project and call library using:
Library work;
use work.fixed_pkg.all;
To my annoyance, they don't come up in the nice red writing I want them to but it works!
I want to use the aspectc++ compiler for a C++11-project. I have read in the manual, that c++11 support will come with version 2. I thought that aspect weaving happens only on the code level, so why does it depend on the used C++ version? Why does aspectc++ care the source code when it just has to weave the aspects to generate a composed piece of code? Is there a way to use aspectc++ for C++11 source code? Or is there an alternative which can handle it?
This post is already a bit older, i know.
Nevertheless I'd like to answer the question why aspectC++ depends on the C++-version:
aspectC++ internally parses the code (amongst other things to identify the locations where to weave the code). Not all of this can be done by external parsers therefore it needs to understand the syntax basically itself.
Some new c++-constructions from C++11 like attributes ([[...]]) could not be handeled by the AspectC++-compiler version < 2.0.
To use c++11 for compiling just use -std=c++11
Does protobuf-net have any APIs to dump a protobuf into human readable form? I was hoping for something like TextFormat.
At the moment, no. I'm in two minds as to whether it is worthwhile adding; in my mind, this defeats most of the benefits of protocol buffers.
However, since Jon's version is a port of the java version you should find that it is feature compatible, so it should exist there.
there is one for java. the build.toString() method returns a string representation but you'll loose the serialization.