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Improvements to coding for itertools.tee():

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* Add error checking code to PyList_Append() call.

* Replace PyObject_CallMethod(to->outbasket, "pop", NULL) with equivalent
  in-line code.  Inlining is important here because the search for the
  pop method will occur for every element returned by the iterator.

* Make tee's dealloc() a little smarter.  If the trailing iterator is
  being deallocated, then the queue data is no longer needed and can
  be freed.
This commit is contained in:
Raymond Hettinger 2003-10-25 06:37:47 +00:00
parent 23b44a39ce
commit 4514369f27
1 changed files with 26 additions and 3 deletions
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29
Modules/itertoolsmodule.c
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@ -46,6 +46,7 @@ ii_next(iiobject *lz)
{ {
teeobject *to = lz->tee; teeobject *to = lz->tee;
PyObject *result, *tmp; PyObject *result, *tmp;
int n;
if (lz->num_seen == to->num_seen) { if (lz->num_seen == to->num_seen) {
/* This instance is leading, use iter to get more data */ /* This instance is leading, use iter to get more data */
@ -53,7 +54,10 @@ ii_next(iiobject *lz)
if (result == NULL) if (result == NULL)
return NULL; return NULL;
if (to->save_mode) if (to->save_mode)
PyList_Append(to->inbasket, result); if(PyList_Append(to->inbasket, result) == -1){
Py_DECREF(result);
return NULL;
}
to->num_seen++; to->num_seen++;
lz->num_seen++; lz->num_seen++;
return result; return result;
@ -66,18 +70,37 @@ ii_next(iiobject *lz)
to->outbasket = to->inbasket; to->outbasket = to->inbasket;
to->inbasket = tmp; to->inbasket = tmp;
PyList_Reverse(to->outbasket); PyList_Reverse(to->outbasket);
assert(PyList_GET_SIZE(to->outbasket) > 0);
} }
/* Pop result from to->outbasket */
n = PyList_GET_SIZE(to->outbasket);
assert(n>0);
result = PyList_GET_ITEM(to->outbasket, n-1);
Py_INCREF(result);
if (PyList_SetSlice(to->outbasket, n-1, n, NULL) == -1) {
Py_DECREF(result);
return NULL;
}
lz->num_seen++; lz->num_seen++;
return PyObject_CallMethod(to->outbasket, "pop", NULL); return result;
} }
static void static void
ii_dealloc(iiobject *ii) ii_dealloc(iiobject *ii)
{ {
teeobject *to = ii->tee;
int n;
PyObject_GC_UnTrack(ii); PyObject_GC_UnTrack(ii);
ii->tee->save_mode = 0; /* Stop saving data */ ii->tee->save_mode = 0; /* Stop saving data */
if (ii->num_seen < to->num_seen) {
/* It is the trailing iterator being freed; this means
that the stored queue data is no longer needed */
n = PyList_GET_SIZE(to->inbasket);
PyList_SetSlice(to->inbasket, 0, n, NULL);
n = PyList_GET_SIZE(to->outbasket);
PyList_SetSlice(to->outbasket, 0, n, NULL);
}
Py_XDECREF(ii->tee); Py_XDECREF(ii->tee);
PyObject_GC_Del(ii); PyObject_GC_Del(ii);
} }