Tidied up the implementations of reversed (including the custom ones
for xrange and list objects).
* list.__reversed__ now checks the length of the sequence object before
calling PyList_GET_ITEM() because the mutable could have changed length.
* all three implementations are now tranparent with respect to length and
maintain the invariant len(it) == len(list(it)) even when the underlying
sequence mutates.
* __builtin__.reversed() now frees the underlying sequence as soon
as the iterator is exhausted.
* the code paths were rearranged so that the most common paths
do not require a jump.
diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
index 1f56728..a6d1611 100644
--- a/Objects/rangeobject.c
+++ b/Objects/rangeobject.c
@@ -288,6 +288,18 @@
return NULL;
}
+static int
+rangeiter_len(rangeiterobject *r)
+{
+ return r->len - r->index;
+}
+
+static PySequenceMethods rangeiter_as_sequence = {
+ (inquiry)rangeiter_len, /* sq_length */
+ 0, /* sq_concat */
+};
+
+
static PyTypeObject Pyrangeiter_Type = {
PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */
@@ -302,7 +314,7 @@
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
- 0, /* tp_as_sequence */
+ &rangeiter_as_sequence, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */