SF bug #604716: faster [None]*n or []*n
Fulfilled request to special case repetitions of lists of length 0 or 1.
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 48f3d7d..7d03506 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -421,14 +421,26 @@
int size;
PyListObject *np;
PyObject **p;
+ PyObject *elem;
if (n < 0)
n = 0;
size = a->ob_size * n;
+ if (size == 0)
+ return PyList_New(0);
if (n && size/n != a->ob_size)
return PyErr_NoMemory();
np = (PyListObject *) PyList_New(size);
if (np == NULL)
return NULL;
+
+ if (a->ob_size == 1) {
+ elem = a->ob_item[0];
+ for (i = 0; i < n; i++) {
+ np->ob_item[i] = elem;
+ Py_INCREF(elem);
+ }
+ return (PyObject *) np;
+ }
p = np->ob_item;
for (i = 0; i < n; i++) {
for (j = 0; j < a->ob_size; j++) {