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* Specialize ins1() into app1() for appends. Saves several unnecessary 

steps and further improves the speed of list append.

* Add guards to the list iterator length method to handle corner cases.
This commit is contained in:
Raymond Hettinger 2004-04-12 13:05:09 +00:00
parent 71b2411566
commit 40a03821ae
1 changed files with 36 additions and 6 deletions
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42
Objects/listobject.c
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@ -180,6 +180,26 @@ PyList_Insert(PyObject *op, int where, PyObject *newitem)
return ins1((PyListObject *)op, where, newitem); return ins1((PyListObject *)op, where, newitem);
} }
static int
app1(PyListObject *self, PyObject *v)
{
int n = PyList_GET_SIZE(self);
assert (v != NULL);
if (n == INT_MAX) {
PyErr_SetString(PyExc_OverflowError,
"cannot add more objects to list");
return -1;
}
if (list_resize(self, n+1) == -1)
return -1;
Py_INCREF(v);
PyList_SET_ITEM(self, n, v);
return 0;
}
int int
PyList_Append(PyObject *op, PyObject *newitem) PyList_Append(PyObject *op, PyObject *newitem)
{ {
@ -187,8 +207,11 @@ PyList_Append(PyObject *op, PyObject *newitem)
PyErr_BadInternalCall(); PyErr_BadInternalCall();
return -1; return -1;
} }
return ins1((PyListObject *)op, if (newitem == NULL) {
(int) ((PyListObject *)op)->ob_size, newitem); PyErr_BadInternalCall();
return -1;
}
return app1((PyListObject *)op, newitem);
} }
/* Methods */ /* Methods */
@ -726,7 +749,7 @@ listextend(PyListObject *self, PyObject *b)
if (i < mn) if (i < mn)
PyList_SET_ITEM(self, i, item); /* steals ref */ PyList_SET_ITEM(self, i, item); /* steals ref */
else { else {
int status = ins1(self, self->ob_size, item); int status = app1(self, item);
Py_DECREF(item); /* append creates a new ref */ Py_DECREF(item); /* append creates a new ref */
if (status < 0) if (status < 0)
goto error; goto error;
@ -2684,8 +2707,12 @@ listiter_next(listiterobject *it)
static int static int
listiter_len(listiterobject *it) listiter_len(listiterobject *it)
{ {
if (it->it_seq) int len;
return PyList_GET_SIZE(it->it_seq) - it->it_index; if (it->it_seq) {
len = PyList_GET_SIZE(it->it_seq) - it->it_index;
if (len >= 0)
return len;
}
return 0; return 0;
} }
@ -2799,7 +2826,10 @@ listreviter_next(listreviterobject *it)
static int static int
listreviter_len(listreviterobject *it) listreviter_len(listreviterobject *it)
{ {
return it->it_index + 1; int len = it->it_index + 1;
if (it->it_seq == NULL || PyList_GET_SIZE(it->it_seq) < len)
return 0;
return len;
} }
static PySequenceMethods listreviter_as_sequence = { static PySequenceMethods listreviter_as_sequence = {