[pypy-dev] serialize and deserialize objects in Pypy

[Yicong Huang]

In general, we don't need to parse or process Pypy object in C code, but
only transfer the object from one Pypy enviroment to another Pypy
enviroment.
I am thinking could we have the alternavtive easier way to do this, like
PyObject in Python?

Could we get the address of the Pypy Object and the length of the object,
and memcpy the content from Pypy to C++ and then from C++ to Pypy?


On Fri, Aug 7, 2015 at 8:08 PM, Maciej Fijalkowski <fijall at gmail.com> wrote:

> yes, you need a serializer protocol, like JSON (or protobuf or
> anything). You generally need to express stuff in a way C can
> understand and read it in python
>
> On Fri, Aug 7, 2015 at 2:06 PM, Yicong Huang <hengha.mao at gmail.com> wrote:
> > The problem is we might need to support several kinds of collection
> objects:
> > list, dict, tuple.
> > In addition, we might not know what is exact type of objects stored in
> the
> > collections. A list might store int, string, double.
> > So it might involve a lot of work to write the python wrapper.
> > Do you have any good ideas?
> >
> > On Fri, Aug 7, 2015 at 7:46 PM, Maciej Fijalkowski <fijall at gmail.com>
> wrote:
> >>
> >> you really can't convert it to the C stuff like that. You need to do:
> >>
> >> foo = ffi.new("int[]", 13)
> >> foo[0] = 12
> >> foo[1] = 55
> >>
> >> etc.
> >>
> >> You can write nice python wrapper around those things too, if the data
> >> is too bare bone.
> >>
> >> On Fri, Aug 7, 2015 at 1:09 PM, Yicong Huang <hengha.mao at gmail.com>
> wrote:
> >> > Hi Maciej,
> >> >
> >> > Could you provide some details on how to use cffi buffers? (a simple
> >> > demo
> >> > code or documents)
> >> > I tried the below code but it did not work.
> >> >
> >> > #python list
> >> > x=[1,2,3,4]
> >> > #intend to convert to c++ char*, but failed
> >> > p=ffi.from_buffer(x)
> >> > #intend to covert back to python list, but failed
> >> > y=ffi.buffer(p)
> >> >
> >> > Thanks!
> >> >
> >> > -Ethan
> >> >
> >> > On Fri, Aug 7, 2015 at 6:24 PM, Maciej Fijalkowski <fijall at gmail.com>
> >> > wrote:
> >> >>
> >> >> you can use cffi buffers (e.g. cffi char*) that you manipulate from
> >> >> python using wrappers. They would behave (sort of) like python
> objects
> >> >> and the wrapper code is really not a performance penalty in most
> cases
> >> >>
> >> >> On Fri, Aug 7, 2015 at 12:19 PM, Yicong Huang <hengha.mao at gmail.com>
> >> >> wrote:
> >> >> > Hi,
> >> >> >
> >> >> > Are there any good methods to serialize Pypy object to C++ char*
> and
> >> >> > deserialize to Pypy object from  C++ char*?
> >> >> >
> >> >> > Our scenario like this:
> >> >> > We have at least two C++ process running, and each process embeded
> >> >> > Pypy
> >> >> > to
> >> >> > execute some functions.
> >> >> > And we woule like to reuse Pypy object from one process to another
> >> >> > process.
> >> >> > For primitive objects, int/char/bool/double etc., we could use cffi
> >> >> > to
> >> >> > pass
> >> >> > objects.
> >> >> > Pypy object -> c++ process 1 -> c++ process 2 -> Pypy object
> >> >> >
> >> >> > But for complex objects, e.g. list/array/dict/tuple, are there any
> >> >> > methods?
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >> > _______________________________________________
> >> >> > pypy-dev mailing list
> >> >> > pypy-dev at python.org
> >> >> > https://mail.python.org/mailman/listinfo/pypy-dev
> >> >> >
> >> >
> >> >
> >
> >
>
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