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Minor performance tweak for deque.index() with a start argument (GH-9440)

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Raymond Hettinger 2018-09-21 01:46:41 -07:00 committed by GitHub
parent fb3e9c00ed
commit b46ad5431d
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2 changed files with 12 additions and 2 deletions
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8
Lib/test/test_deque.py
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@ -288,6 +288,14 @@ class TestBasic(unittest.TestCase):
else:
self.assertEqual(d.index(element, start, stop), target)
# Test large start argument
d = deque(range(0, 10000, 10))
for step in range(100):
i = d.index(8500, 700)
self.assertEqual(d[i], 8500)
# Repeat test with a different internal offset
d.rotate()
def test_index_bug_24913(self):
d = deque('A' * 3)
with self.assertRaises(ValueError):

6
Modules/_collectionsmodule.c
View File

@ -1050,8 +1050,10 @@ deque_index(dequeobject *deque, PyObject *const *args, Py_ssize_t nargs)
start = stop;
assert(0 <= start && start <= stop && stop <= Py_SIZE(deque));
/* XXX Replace this loop with faster code from deque_item() */
for (i=0 ; i<start ; i++) {
for (i=0 ; i < start - BLOCKLEN ; i += BLOCKLEN) {
b = b->rightlink;
}
for ( ; i < start ; i++) {
index++;
if (index == BLOCKLEN) {
b = b->rightlink;