listobject.c: added optional cmp function to list.sort().

diff --git a/Objects/listobject.c b/Objects/listobject.c
index 6992a0fb843aa5d8b2bb9613cda5ffd5f014837e..996c28949a0e907f9adb5e5a1420f5710180ddf2 100644 (file)
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -26,6 +26,8 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 #include "allobjects.h"
 #include "modsupport.h"
+#include "compile.h" /* Needed by ceval.h */
+#include "ceval.h" /* For call_object() */
 
 object *
 newlistobject(size)
@@ -471,11 +473,46 @@ listappend(self, args)
        return ins(self, (int) self->ob_size, args);
 }
 
+static object *cmpfunc;
+
 static int
 cmp(v, w)
        char *v, *w;
 {
-       return cmpobject(* (object **) v, * (object **) w);
+       object *t, *res;
+       long i;
+
+       if (err_occurred())
+               return 0;
+
+       if (cmpfunc == NULL)
+               return cmpobject(* (object **) v, * (object **) w);
+
+       /* Call the user-supplied comparison function */
+       t = newtupleobject(2);
+       if (t == NULL)
+               return 0;
+       INCREF(* (object **) v);
+       settupleitem(t, 0, * (object **) v);
+       INCREF(* (object **) w);
+       settupleitem(t, 1, * (object **) w);
+       res = call_object(cmpfunc, t);
+       DECREF(t);
+       if (res == NULL)
+               return 0;
+       if (!is_intobject(res)) {
+               err_setstr(TypeError, "comparison function should return int");
+               i = 0;
+       }
+       else {
+               i = getintvalue(res);
+               if (i < 0)
+                       i = -1;
+               else if (i > 0)
+                       i = 1;
+       }
+       DECREF(res);
+       return (int) i;
 }
 
 static object *
@@ -483,14 +520,24 @@ listsort(self, args)
        listobject *self;
        object *args;
 {
-       if (args != NULL) {
-               err_badarg();
-               return NULL;
+       object *save_cmpfunc;
+       if (self->ob_size <= 1) {
+               INCREF(None);
+               return None;
+       }
+       save_cmpfunc = cmpfunc;
+       cmpfunc = args;
+       if (cmpfunc != NULL) {
+               /* Test the comparison function for obvious errors */
+               (void) cmp(&self->ob_item[0], &self->ob_item[1]);
+               if (err_occurred()) {
+                       cmpfunc = save_cmpfunc;
+                       return NULL;
+               }
        }
-       err_clear();
-       if (self->ob_size > 1)
-               qsort((char *)self->ob_item,
+       qsort((char *)self->ob_item,
                                (int) self->ob_size, sizeof(object *), cmp);
+       cmpfunc = save_cmpfunc;
        if (err_occurred())
                return NULL;
        INCREF(None);