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Optimize tuple_slice() and make further improvements to list_slice()

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and list.extend().  Factoring the inner loops to remove the constant
structure references and fixed offsets gives speedups ranging from
20% to 30%.
This commit is contained in:
Raymond Hettinger 2004-03-08 07:25:05 +00:00
parent f0e3569a28
commit b7d05db0be
3 changed files with 28 additions and 18 deletions
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30
Objects/listobject.c
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@ -342,6 +342,7 @@ static PyObject *
list_slice(PyListObject *a, int ilow, int ihigh)
{
PyListObject *np;
PyObject **src, **dest;
int i, len;
if (ilow < 0)
ilow = 0;
@ -356,10 +357,12 @@ list_slice(PyListObject *a, int ilow, int ihigh)
if (np == NULL)
return NULL;
src = a->ob_item + ilow;
dest = np->ob_item;
for (i = 0; i < len; i++) {
PyObject *v = a->ob_item[i+ilow];
PyObject *v = src[i];
Py_INCREF(v);
np->ob_item[i] = v;
dest[i] = v;
}
return (PyObject *)np;
}
@ -646,6 +649,7 @@ listextend_internal(PyListObject *self, PyObject *b)
register int selflen = PyList_GET_SIZE(self);
int blen;
register int i;
PyObject **src, **dest;
if (PyObject_Size(b) == 0) {
/* short circuit when b is empty */
@ -678,19 +682,17 @@ listextend_internal(PyListObject *self, PyObject *b)
}
/* populate the end of self with b's items */
if (PyList_Check(b)) {
for (i = 0; i < blen; i++) {
PyObject *o = PyList_GET_ITEM(b, i);
Py_INCREF(o);
PyList_SET_ITEM(self, i+selflen, o);
}
} else {
if (PyList_Check(b))
src = ((PyListObject *)b)->ob_item;
else {
assert (PyTuple_Check(b));
for (i = 0; i < blen; i++) {
PyObject *o = PyTuple_GET_ITEM(b, i);
Py_INCREF(o);
PyList_SET_ITEM(self, i+selflen, o);
}
src = ((PyTupleObject *)b)->ob_item;
}
dest = self->ob_item + selflen;
for (i = 0; i < blen; i++) {
PyObject *o = src[i];
Py_INCREF(o);
dest[i] = o;
}
Py_DECREF(b);
return 0;