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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#include "PyVTKExtras.h"
#include "PyVTKReference.h"
#include "vtkABINamespace.h"
#include "vtkPythonCompatibility.h"
// Silence warning like
// "dereferencing type-punned pointer will break strict-aliasing rules"
// it happens because this kind of expression: (long *)&ptr
#if defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wstrict-aliasing"
#endif
//------------------------------------------------------------------------------
// Helper function for the buffer_shared() check: get the pointer and
// size (in bytes) of the buffer of the provided object. A return
// value of zero indicates that an exception was raised.
static void* buffer_pointer_and_size(PyObject* o, Py_ssize_t* size)
{
void* ptr = nullptr;
// New buffer protocol
Py_buffer view = { nullptr, nullptr, 0, 0, 0, 0, nullptr, nullptr, nullptr, nullptr, nullptr };
if (PyObject_CheckBuffer(o))
{
// Check for a simple buffer
if (PyObject_GetBuffer(o, &view, PyBUF_SIMPLE) == -1)
{
// Check for a C or Fortran contiguous buffer
PyErr_Clear();
if (PyObject_GetBuffer(o, &view, PyBUF_STRIDES) == -1)
{
return nullptr;
}
}
ptr = view.buf;
*size = view.len;
PyBuffer_Release(&view);
if (ptr)
{
return ptr;
}
}
PyErr_SetString(PyExc_TypeError, "object does not have a readable buffer");
return nullptr;
}
//------------------------------------------------------------------------------
static PyObject* PyVTKExtras_buffer_shared(PyObject*, PyObject* args)
{
PyObject* ob[2] = { nullptr, nullptr };
if (PyArg_UnpackTuple(args, "buffer_shared", 2, 2, &ob[0], &ob[1]))
{
void* ptr[2] = { nullptr, nullptr };
Py_ssize_t size[2] = { 0, 0 };
for (int i = 0; i < 2; i++)
{
ptr[i] = buffer_pointer_and_size(ob[i], &size[i]);
if (!ptr[i])
{
break;
}
}
// check if the pointers and memory size are equal
if (ptr[0] && ptr[1])
{
if (ptr[0] == ptr[1] && size[0] == size[1])
{
Py_RETURN_TRUE;
}
else
{
Py_RETURN_FALSE;
}
}
}
return nullptr;
}
//------------------------------------------------------------------------------
static PyMethodDef PyVTKExtras_Methods[] = {
{ "buffer_shared", PyVTKExtras_buffer_shared, METH_VARARGS,
"Check if two objects share the same buffer, meaning that they"
" point to the same block of memory. An TypeError exception will"
" be raised if either of the objects does not provide a buffer." },
{ nullptr, nullptr, 0, nullptr }
};
//------------------------------------------------------------------------------
// Exported method called by vtkCommonCorePythonInit
void PyVTKAddFile_PyVTKExtras(PyObject* dict)
{
// It is necessary to call PyType_Ready() on all subclasses
PyType_Ready(&PyVTKNumberReference_Type);
PyType_Ready(&PyVTKStringReference_Type);
PyType_Ready(&PyVTKTupleReference_Type);
// Add the "mutable" object (used for C++ pass-by-reference)
PyObject* o = (PyObject*)&PyVTKReference_Type;
PyDict_SetItemString(dict, "reference", o); // new name (as of VTK 8.1)
PyDict_SetItemString(dict, "mutable", o); // old name
for (PyMethodDef* meth = PyVTKExtras_Methods; meth->ml_name != nullptr; meth++)
{
// Third argument would be the module object, but all we have is
// the module's dict, and it's safe to set it to nullptr.
o = PyCFunction_NewEx(meth, nullptr, nullptr);
if (o && PyDict_SetItemString(dict, meth->ml_name, o) != 0)
{
Py_DECREF(o);
}
}
}
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