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SF patch #1200051: Small optimization for PyDict_Merge()

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(Contributed by Barry Warsaw and Matt Messier.)
This commit is contained in:
Raymond Hettinger 2005-05-14 18:08:25 +00:00
parent 0f43983aa3
commit 186e739d29
1 changed files with 6 additions and 0 deletions
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6
Objects/dictobject.c
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@ -1203,6 +1203,12 @@ PyDict_Merge(PyObject *a, PyObject *b, int override)
if (other == mp || other->ma_used == 0) if (other == mp || other->ma_used == 0)
/* a.update(a) or a.update({}); nothing to do */ /* a.update(a) or a.update({}); nothing to do */
return 0; return 0;
if (mp->ma_used == 0)
/* Since the target dict is empty, PyDict_GetItem()
* always returns NULL. Setting override to 1
* skips the unnecessary test.
*/
override = 1;
/* Do one big resize at the start, rather than /* Do one big resize at the start, rather than
* incrementally resizing as we insert new items. Expect * incrementally resizing as we insert new items. Expect
* that there will be no (or few) overlapping keys. * that there will be no (or few) overlapping keys.