Christopher Barker wrote:
Travis,
First, thanks for doing this -- Python really needs it!
While this approach
works, it requires attribute lookups which can be expensive when sharing many small arrays.Ah, I do like reducing that overhead -- I know I use arrays a lot for small data sets too, so that overhead can be significant.
I'm not well qualified to review the tech details, but to make sure I have this right:
static PyObject* bf_getarrayview (PyObject *obj) This function must return a new reference to a PyArrViewObject which contains the details of the array information exposed by the object. If failure occurs, then NULL is returned and an exception set.So If I have some C code that wants to use any array passed in, I can just call:
bf_getarrayview (obj)
Yes you could call this (but you would call it from the type object like this
obj->ob_type->tp_as_buffer->bf_getarrayview(obj)
Or more likely (and I should add this to the C-API) you would call.
PyArrayView_FromObject(obj)
which does this under the covers.
and if it doesn't return NULL, I have a valid array that I can query to see if it fits what I'm expecting.
Have I got that right?
If so, this would be great.
By the way,, how compatible is this with the existing buffer protocol?
It's basically orthogonal. In other-words, if you defined the array view protocol you would not need the buffer protocol at all. But you could easily define both.
-Travis