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| author | Raymond Hettinger <rhettinger@users.noreply.github.com> | 2018-09-21 08:46:41 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2018-09-21 08:46:41 (GMT) |
| commit | b46ad5431d2643f61e929c1ffec48766b2fafd75 (patch) | |
| tree | d82d6b7498df61a8f86afdb38f5396c826b7c4a3 | |
| parent | fb3e9c00ed79f4d880ab9a67aab861eb3660ec75 (diff) | |
| download | cpython-b46ad5431d2643f61e929c1ffec48766b2fafd75.zip cpython-b46ad5431d2643f61e929c1ffec48766b2fafd75.tar.gz cpython-b46ad5431d2643f61e929c1ffec48766b2fafd75.tar.bz2 | |
Minor performance tweak for deque.index() with a start argument (GH-9440)
| -rw-r--r-- | Lib/test/test_deque.py | 8 | ||||
| -rw-r--r-- | Modules/_collectionsmodule.c | 6 |
2 files changed, 12 insertions, 2 deletions
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py index 9211360..51b66b7 100644 --- a/Lib/test/test_deque.py +++ b/Lib/test/test_deque.py @@ -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): diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c index 935b434..267cf07 100644 --- a/Modules/_collectionsmodule.c +++ b/Modules/_collectionsmodule.c @@ -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; |