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Optimize PyList_AsTuple(). Improve cache performance by doing the

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pointer copy and object increment in one pass.  For small lists,
save the overhead of the call to memcpy() -- this comes up in
calls like f(*listcomp).
This commit is contained in:
Raymond Hettinger 2007-12-15 00:07:25 +00:00
parent c67a15d865
commit 6c87af5d87
1 changed files with 5 additions and 5 deletions
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10
Objects/listobject.c
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@ -2186,7 +2186,7 @@ PyObject *
PyList_AsTuple(PyObject *v) PyList_AsTuple(PyObject *v)
{ {
PyObject *w; PyObject *w;
PyObject **p; PyObject **p, **q;
Py_ssize_t n; Py_ssize_t n;
if (v == NULL || !PyList_Check(v)) { if (v == NULL || !PyList_Check(v)) {
PyErr_BadInternalCall(); PyErr_BadInternalCall();
@ -2197,12 +2197,12 @@ PyList_AsTuple(PyObject *v)
if (w == NULL) if (w == NULL)
return NULL; return NULL;
p = ((PyTupleObject *)w)->ob_item; p = ((PyTupleObject *)w)->ob_item;
memcpy((void *)p, q = ((PyListObject *)v)->ob_item;
(void *)((PyListObject *)v)->ob_item,
n*sizeof(PyObject *));
while (--n >= 0) { while (--n >= 0) {
Py_INCREF(*p); Py_INCREF(*q);
*p = *q;
p++; p++;
q++;
} }
return w; return w;
} }