[Python-checkins] r70296 - in python/trunk: Lib/test/test_deque.py Modules/_collectionsmodule.c
raymond.hettinger
python-checkins at python.org
Tue Mar 10 10:31:49 CET 2009
Author: raymond.hettinger
Date: Tue Mar 10 10:31:48 2009
New Revision: 70296
Log:
Small optimization for corner case where maxlen==0.
Modified:
python/trunk/Lib/test/test_deque.py
python/trunk/Modules/_collectionsmodule.c
Modified: python/trunk/Lib/test/test_deque.py
==============================================================================
--- python/trunk/Lib/test/test_deque.py (original)
+++ python/trunk/Lib/test/test_deque.py Tue Mar 10 10:31:48 2009
@@ -50,7 +50,9 @@
def test_maxlen(self):
self.assertRaises(ValueError, deque, 'abc', -1)
self.assertRaises(ValueError, deque, 'abc', -2)
- d = deque(range(10), maxlen=3)
+ it = iter(range(10))
+ d = deque(it, maxlen=3)
+ self.assertEqual(list(it), [])
self.assertEqual(repr(d), 'deque([7, 8, 9], maxlen=3)')
self.assertEqual(list(d), range(7, 10))
self.assertEqual(d, deque(range(10), 3))
@@ -87,6 +89,21 @@
fo.close()
test_support.unlink(test_support.TESTFN)
+ def test_maxlen_zero(self):
+ it = iter(range(100))
+ deque(it, maxlen=0)
+ self.assertEqual(list(it), [])
+
+ it = iter(range(100))
+ d = deque(maxlen=0)
+ d.extend(it)
+ self.assertEqual(list(it), [])
+
+ it = iter(range(100))
+ d = deque(maxlen=0)
+ d.extendleft(it)
+ self.assertEqual(list(it), [])
+
def test_comparisons(self):
d = deque('xabc'); d.popleft()
for e in [d, deque('abc'), deque('ab'), deque(), list(d)]:
Modified: python/trunk/Modules/_collectionsmodule.c
==============================================================================
--- python/trunk/Modules/_collectionsmodule.c (original)
+++ python/trunk/Modules/_collectionsmodule.c Tue Mar 10 10:31:48 2009
@@ -276,6 +276,23 @@
PyDoc_STRVAR(appendleft_doc, "Add an element to the left side of the deque.");
+
+/* Run an iterator to exhaustion. Shortcut for
+ the extend/extendleft methods when maxlen == 0. */
+static PyObject*
+consume_iterator(PyObject *it)
+{
+ PyObject *item;
+
+ while ((item = PyIter_Next(it)) != NULL) {
+ Py_DECREF(item);
+ }
+ Py_DECREF(it);
+ if (PyErr_Occurred())
+ return NULL;
+ Py_RETURN_NONE;
+}
+
static PyObject *
deque_extend(dequeobject *deque, PyObject *iterable)
{
@@ -285,6 +302,9 @@
if (it == NULL)
return NULL;
+ if (deque->maxlen == 0)
+ return consume_iterator(it);
+
while ((item = PyIter_Next(it)) != NULL) {
deque->state++;
if (deque->rightindex == BLOCKLEN-1) {
@@ -323,6 +343,9 @@
if (it == NULL)
return NULL;
+ if (deque->maxlen == 0)
+ return consume_iterator(it);
+
while ((item = PyIter_Next(it)) != NULL) {
deque->state++;
if (deque->leftindex == 0) {
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