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author | Andrew Dalke <dalke@dalkescientific.com> | 2006-05-26 22:49:03 (GMT) |
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committer | Andrew Dalke <dalke@dalkescientific.com> | 2006-05-26 22:49:03 (GMT) |
commit | 7e0a62ea9052faf0e19dc2438124751b8f68ce16 (patch) | |
tree | 71aed0fd398e7f7e37b8edad8728f8404e4e4522 /Objects | |
parent | 57ad0607223d65472e7beb63e353224d8a901fac (diff) | |
download | cpython-7e0a62ea9052faf0e19dc2438124751b8f68ce16.zip cpython-7e0a62ea9052faf0e19dc2438124751b8f68ce16.tar.gz cpython-7e0a62ea9052faf0e19dc2438124751b8f68ce16.tar.bz2 |
Added description of why splitlines doesn't use the prealloc strategy
Diffstat (limited to 'Objects')
-rw-r--r-- | Objects/stringobject.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Objects/stringobject.c b/Objects/stringobject.c index c59c74e..7e93783 100644 --- a/Objects/stringobject.c +++ b/Objects/stringobject.c @@ -3768,6 +3768,14 @@ string_splitlines(PyStringObject *self, PyObject *args) data = PyString_AS_STRING(self); len = PyString_GET_SIZE(self); + /* This does not use the preallocated list because splitlines is + usually run with hundreds of newlines. The overhead of + switching between PyList_SET_ITEM and append causes about a + 2-3% slowdown for that common case. A smarter implementation + could move the if check out, so the SET_ITEMs are done first + and the appends only done when the prealloc buffer is full. + That's too much work for little gain.*/ + list = PyList_New(0); if (!list) goto onError; |