Function get_array_ufunc_overrides

numpy/core/src/umath/override.c:25–93

* For each positional argument and each argument in a possible "out" * keyword, look for overrides of the standard ufunc behaviour, i.e., * non-default __array_ufunc__ methods. * * Returns the number of overrides, setting corresponding objects * in PyObject array ``with_override`` and the corresponding * __array_ufunc__ methods in ``methods`` (both using new references). * * Only the first

 * Returns -1 on failure.
 */
static int
get_array_ufunc_overrides(PyObject *in_args, PyObject *out_args, PyObject *wheremask_obj,
                          PyObject **with_override, PyObject **methods)
{
    int i;
    int num_override_args = 0;
    int narg, nout, nwhere;

    narg = (int)PyTuple_GET_SIZE(in_args);
    /* It is valid for out_args to be NULL: */
    nout = (out_args != NULL) ? (int)PyTuple_GET_SIZE(out_args) : 0;
    nwhere = (wheremask_obj != NULL) ? 1: 0;

    for (i = 0; i < narg + nout + nwhere; ++i) {
        PyObject *obj;
        int j;
        int new_class = 1;

        if (i < narg) {
            obj = PyTuple_GET_ITEM(in_args, i);
        }
        else if (i < narg + nout){
            obj = PyTuple_GET_ITEM(out_args, i - narg);
        }
        else {
            obj = wheremask_obj;
        }
        /*
         * Have we seen this class before?  If so, ignore.
         */
        for (j = 0; j < num_override_args; j++) {
            new_class = (Py_TYPE(obj) != Py_TYPE(with_override[j]));
            if (!new_class) {
                break;
            }
        }
        if (new_class) {
            /*
             * Now see if the object provides an __array_ufunc__. However, we should
             * ignore the base ndarray.__ufunc__, so we skip any ndarray as well as
             * any ndarray subclass instances that did not override __array_ufunc__.
             */
            PyObject *method = PyUFuncOverride_GetNonDefaultArrayUfunc(obj);
            if (method == NULL) {
                continue;
            }
            if (method == Py_None) {
                PyErr_Format(PyExc_TypeError,
                             "operand '%.200s' does not support ufuncs "
                             "(__array_ufunc__=None)",
                             obj->ob_type->tp_name);
                Py_DECREF(method);
                goto fail;
            }
            Py_INCREF(obj);
            with_override[num_override_args] = obj;
            methods[num_override_args] = method;
            ++num_override_args;