Antoine Pitrou wrote: > Le mardi 09 décembre 2008 à 22:33 +1000, Nick Coghlan a écrit : >> memoryview also currently gets the shape wrong on slices: > > I know, that's what I'm trying to fix...
Yes, I was slightly misled by your use of slice assignment to demonstrate the problem. It also turns out that while assignment to memoryviews has issues, and so does slicing, there is a fundamental problem with the length calculation when a memoryview is first created which is further confusing matters. For the slicing problem in particular, memoryview is currently trying to get away with only one Py_buffer object when it needs TWO. The first Py_buffer object needs to describe the view the memoryview has of the target object (i.e. it describes the entire data area of the target). The shape/strides/etc pointers in that struct are owned by the target object. The existing self->view tends to fill this role fairly well. The *second* (currently nonexistent) Py_buffer object needs to describe the memory layout that the memoryview exposes to the rest of the world. The pointers in *this* struct will be owned by the memoryview object and accurately reflect any changes in shape due to slicing operations. Currently, memoryview is trying to make the first Py_buffer also fill the role of the second one, and that obviously isn't going to work for subviews. Cheers, Nick. -- Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia --------------------------------------------------------------- _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
