Function PyArray_BufferConverter

numpy/core/src/multiarray/conversion_utils.c:275–316

NUMPY_API * Get buffer chunk from object * * this function takes a Python object which exposes the (single-segment) * buffer interface and returns a pointer to the data segment * * You should increment the reference count by one of buf->base * if you will hang on to a reference * * You only get a borrowed reference to the object. Do not free the * memory... */

 * memory...
 */
NPY_NO_EXPORT int
PyArray_BufferConverter(PyObject *obj, PyArray_Chunk *buf)
{
    Py_buffer view;

    buf->ptr = NULL;
    buf->flags = NPY_ARRAY_BEHAVED;
    buf->base = NULL;
    if (obj == Py_None) {
        return NPY_SUCCEED;
    }

    if (PyObject_GetBuffer(obj, &view,
                PyBUF_ANY_CONTIGUOUS|PyBUF_WRITABLE|PyBUF_SIMPLE) != 0) {
        PyErr_Clear();
        buf->flags &= ~NPY_ARRAY_WRITEABLE;
        if (PyObject_GetBuffer(obj, &view,
                PyBUF_ANY_CONTIGUOUS|PyBUF_SIMPLE) != 0) {
            return NPY_FAIL;
        }
    }

    buf->ptr = view.buf;
    buf->len = (npy_intp) view.len;

    /*
     * In Python 3 both of the deprecated functions PyObject_AsWriteBuffer and
     * PyObject_AsReadBuffer that this code replaces release the buffer. It is
     * up to the object that supplies the buffer to guarantee that the buffer
     * sticks around after the release.
     */
    PyBuffer_Release(&view);

    /* Point to the base of the buffer object if present */
    if (PyMemoryView_Check(obj)) {
        buf->base = PyMemoryView_GET_BASE(obj);
    }
    if (buf->base == NULL) {
        buf->base = obj;
    }
    return NPY_SUCCEED;
}

/*NUMPY_API
 * Get axis from an object (possibly None) -- a converter function,