/* Try a 3-way comparison, returning an int. Return:
-2 for an exception;
-1 if v < w;
0 if v == w;
1 if v > w;
2 if this particular 3-way comparison is not implemented or undefined.
*/
static int
try_3way_compare(PyObject *v, PyObject *w)
{
int c;
cmpfunc f;
/* Comparisons involving instances are given to instance_compare,
which has the same return conventions as this function. */
f = v->ob_type->tp_compare;
if (PyInstance_Check(v))
return (*f)(v, w);
if (PyInstance_Check(w))
return (*w->ob_type->tp_compare)(v, w);
/* If both have the same (non-NULL) tp_compare, use it. */
if (f != NULL && f == w->ob_type->tp_compare) {
c = (*f)(v, w);
if (c < 0 && PyErr_Occurred())
return -1;
return c < 0 ? -1 : c > 0 ? 1 : 0;
}
/* If either tp_compare is _PyObject_SlotCompare, that's safe. */
if (f == _PyObject_SlotCompare ||
w->ob_type->tp_compare == _PyObject_SlotCompare)
return _PyObject_SlotCompare(v, w);
/* Try coercion; if it fails, give up */
c = PyNumber_CoerceEx(&v, &w);
if (c < 0)
return -2;
if (c > 0)
return 2;
/* Try v's comparison, if defined */
if ((f = v->ob_type->tp_compare) != NULL) {
c = (*f)(v, w);
Py_DECREF(v);
Py_DECREF(w);
if (c < 0 && PyErr_Occurred())
return -2;
return c < 0 ? -1 : c > 0 ? 1 : 0;
}
/* Try w's comparison, if defined */
if ((f = w->ob_type->tp_compare) != NULL) {
c = (*f)(w, v); /* swapped! */
Py_DECREF(v);
Py_DECREF(w);
if (c < 0 && PyErr_Occurred())
return -2;
return c < 0 ? 1 : c > 0 ? -1 : 0; /* negated! */
}
/* No comparison defined */
Py_DECREF(v);
Py_DECREF(w);
return 2;
}
/* Try a 3-way comparison, returning an int. Return:
-2 for an exception;
-1 if v < w;
0 if v == w;
1 if v > w;
2 if this particular 3-way comparison is not implemented or undefined.
*/
static int
try_3way_compare(PyObject *v, PyObject *w)
{
int c;
cmpfunc f;
/* Comparisons involving instances are given to instance_compare,
which has the same return conventions as this function. */
f = v->ob_type->tp_compare;
if (PyInstance_Check(v))
return (*f)(v, w);
if (PyInstance_Check(w))
return (*w->ob_type->tp_compare)(v, w);
/* If both have the same (non-NULL) tp_compare, use it. */
if (f != NULL && f == w->ob_type->tp_compare) {
c = (*f)(v, w);
return adjust_tp_compare(c);
}
/* If either tp_compare is _PyObject_SlotCompare, that's safe. */
if (f == _PyObject_SlotCompare ||
w->ob_type->tp_compare == _PyObject_SlotCompare)
return _PyObject_SlotCompare(v, w);
/* If we're here, v and w,
a) are not instances;
b) have different types or a type without tp_compare; and
c) don't have a user-defined tp_compare.
tp_compare implementations in C assume that both arguments
have their type, so we give up if the coercion fails or if
it yields types which are still incompatible (which can
happen with a user-defined nb_coerce).
*/
c = PyNumber_CoerceEx(&v, &w);
if (c < 0)
return -2;
if (c > 0)
return 2;
f = v->ob_type->tp_compare;
if (f != NULL && f == w->ob_type->tp_compare) {
c = (*f)(v, w);
Py_DECREF(v);
Py_DECREF(w);
return adjust_tp_compare(c);
}
/* No comparison defined */
Py_DECREF(v);
Py_DECREF(w);
return 2;
}
