/* Do a 3-way comparison, by hook or by crook. Return:
-2 for an exception (but see below);
-1 if v < w;
0 if v == w;
1 if v > w;
BUT: if the object implements a tp_compare function, it returns
whatever this function returns (whether with an exception or not).
*/
static int
do_cmp(PyObject *v, PyObject *w)
{
int c;
cmpfunc f;
if (v->ob_type == w->ob_type
&& (f = v->ob_type->tp_compare) != NULL) {
c = (*f)(v, w);
if (PyInstance_Check(v)) {
/* Instance tp_compare has a different signature.
But if it returns undefined we fall through. */
if (c != 2)
return c;
/* Else fall through to try_rich_to_3way_compare() */
}
else
return adjust_tp_compare(c);
}
/* We only get here if one of the following is true:
a) v and w have different types
b) v and w have the same type, which doesn't have tp_compare
c) v and w are instances, and either __cmp__ is not defined or
__cmp__ returns NotImplemented
*/
c = try_rich_to_3way_compare(v, w);
if (c < 2)
return c;
c = try_3way_compare(v, w);
if (c < 2)
return c;
return default_3way_compare(v, w);
}
/* We want a rich comparison but don't have one. Try a 3-way cmp instead.
Return
NULL if error
Py_True if v op w
Py_False if not (v op w)
*/
static PyObject *
try_3way_to_rich_compare(PyObject *v, PyObject *w, int op)
{
int c;
c = try_3way_compare(v, w);
if (c >= 2)
c = default_3way_compare(v, w);
if (c <= -2)
return NULL;
return convert_3way_to_object(op, c);
}
/* Do a 3-way comparison, by hook or by crook. Return:
-2 for an exception;
-1 if v < w;
0 if v == w;
1 if v > w;
If the object implements a tp_compare function, it returns
whatever this function returns (whether with an exception or not).
*/
static int
do_cmp(PyObject *v, PyObject *w)
{
int c;
cmpfunc f;
if (v->ob_type == w->ob_type
&& (f = v->ob_type->tp_compare) != NULL) {
c = (*f)(v, w);
if (c != 2 || !PyInstance_Check(v))
return c;
}
c = try_rich_to_3way_compare(v, w);
if (c < 2)
return c;
c = try_3way_compare(v, w);
if (c < 2)
return c;
return default_3way_compare(v, w);
}
