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Apply pre-sizing optimization to a broader class of objects.

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Formerly, the length was only fetched from sequence objects.
Now, any object that reports its length can benefit from pre-sizing.
This commit is contained in:
Raymond Hettinger 2004-01-04 11:00:08 +00:00
parent 4618cc09ec
commit b86269db45
2 changed files with 8 additions and 16 deletions
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12
Objects/abstract.c
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@ -1448,15 +1448,11 @@ PySequence_List(PyObject *v)
return NULL; return NULL;
/* Guess a result list size. */ /* Guess a result list size. */
n = -1; /* unknown */ n = PyObject_Size(v);
if (PySequence_Check(v) && if (n < 0) {
v->ob_type->tp_as_sequence->sq_length) { PyErr_Clear();
n = PySequence_Size(v);
if (n < 0)
PyErr_Clear();
}
if (n < 0)
n = 8; /* arbitrary */ n = 8; /* arbitrary */
}
result = PyList_New(n); result = PyList_New(n);
if (result == NULL) { if (result == NULL) {
Py_DECREF(it); Py_DECREF(it);

12
Python/bltinmodule.c
View file

@ -153,15 +153,11 @@ builtin_filter(PyObject *self, PyObject *args)
return NULL; return NULL;
/* Guess a result list size. */ /* Guess a result list size. */
len = -1; /* unknown */ len = PyObject_Size(seq);
if (PySequence_Check(seq) && if (len < 0) {
seq->ob_type->tp_as_sequence->sq_length) { PyErr_Clear();
len = PySequence_Size(seq); len = 8; /* arbitrary */
if (len < 0)
PyErr_Clear();
} }
if (len < 0)
len = 8; /* arbitrary */
/* Pre-allocate argument list tuple. */ /* Pre-allocate argument list tuple. */
arg = PyTuple_New(1); arg = PyTuple_New(1);