Function _discover_array_parameters

numpy/core/src/multiarray/array_coercion.c:1363–1408

* Python API function to expose the dtype+shape discovery functionality * directly. */

 * directly.
 */
NPY_NO_EXPORT PyObject *
_discover_array_parameters(PyObject *NPY_UNUSED(self),
        PyObject *const *args, Py_ssize_t len_args, PyObject *kwnames)
{
    PyObject *obj;
    npy_dtype_info dt_info = {NULL, NULL};
    npy_intp shape[NPY_MAXDIMS];

    NPY_PREPARE_ARGPARSER;
    if (npy_parse_arguments(
            "_discover_array_parameters", args, len_args, kwnames,
            "", NULL, &obj,
            "|dtype", &PyArray_DTypeOrDescrConverterOptional, &dt_info,
            NULL, NULL, NULL) < 0) {
        /* fixed is last to parse, so never necessary to clean up */
        return NULL;
    }

    coercion_cache_obj *coercion_cache = NULL;
    PyObject *out_dtype = NULL;
    int ndim = PyArray_DiscoverDTypeAndShape(
            obj, NPY_MAXDIMS, shape,
            &coercion_cache,
            dt_info.dtype, dt_info.descr, (PyArray_Descr **)&out_dtype, 0);
    Py_XDECREF(dt_info.dtype);
    Py_XDECREF(dt_info.descr);
    if (ndim < 0) {
        return NULL;
    }
    npy_free_coercion_cache(coercion_cache);
    if (out_dtype == NULL) {
        /* Empty sequence, report this as None. */
        out_dtype = Py_None;
        Py_INCREF(Py_None);
    }

    PyObject *shape_tuple = PyArray_IntTupleFromIntp(ndim, shape);
    if (shape_tuple == NULL) {
        return NULL;
    }

    PyObject *res = PyTuple_Pack(2, (PyObject *)out_dtype, shape_tuple);
    Py_DECREF(out_dtype);
    Py_DECREF(shape_tuple);
    return res;
}