Description
Hi everybody, I like to use custom types for tables in the object based API. The behavior should be equal to the "native_type" attribute for structs. I hope to get some feedback on the idea and possible pack and unpack APIs.
Example:
table MatrixXd (native_type:"Eigen::MatrixXd") {
rows:uint32;
data:[double];
}
table Signal {
mat:MatrixXd;
}
I like to get an object API similar to:
struct SignalT {
Eigen::MatrixXd mat; // instead of std::unique_ptr<MatrixXdT>mat;
}
For structs the user has to specify the following functions:
namespace flatbuffers {
native_type UnPack(const FlatbufferStruct& obj);
FlatbufferStruct Pack(const native_type& obj);
}
I think this is no suitable interface for tables, as "Pack" should directly map to a FlatBufferBuilder.
UnPack
default is { auto _e = mat(); if (_e) _o->mat = std::unique_ptr<MatrixXdT>(_e->UnPack(_resolver)); };
The actual unpack functionality is implemented in "UnPackTo". Both UnPack and UnPackTo are members of the generated code and thus can not be user defined. I would suggest:
native_type UnPack(const FlatbufferTable& obj, const flatbuffers::resolver_function_t *_resolver = nullptr); or alternatively
void UnPackTo(native_type *_o, const FlatbufferTable& obj, const flatbuffers::resolver_function_t *_resolver = nullptr);
I would prefer the first version. Return value optimization should do it's job.
Pack There is a "Pack" method generated for each Table. On the other hand there are two overloaded CreateType functions which do the actual work. I think the interface is similar to what we like to have.
Suggestion:
inline flatbuffers::Offset<Signal> CreateSignal(flatbuffers::FlatBufferBuilder &_fbb, const native_type &_o, const flatbuffers::rehasher_function_t *_rehasher);
I think it is possible to clean up the various generated code pack and unpack functions. For compatibility reasons we should not do so? I am looking forward to some feedback.
Best regards Thomas