Several of the tools can make direct calls the inner iterators.

diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index a76d8c2e00926dd8b6b90474eb3592e0e185faff..5e359de3f50503082169614684e44636a5d28d62 100644 (file)
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -235,10 +235,12 @@ static PyObject *
 dropwhile_next(dropwhileobject *lz)
 {
        PyObject *item, *good;
+       PyObject *it = lz->it;
        long ok;
 
        for (;;) {
-               item = PyIter_Next(lz->it);
+               assert(PyIter_Check(it));
+               item = (*it->ob_type->tp_iternext)(it);
                if (item == NULL)
                        return NULL;
                if (lz->start == 1)
@@ -389,12 +391,14 @@ static PyObject *
 takewhile_next(takewhileobject *lz)
 {
        PyObject *item, *good;
+       PyObject *it = lz->it;
        long ok;
 
        if (lz->stop == 1)
                return NULL;
 
-       item = PyIter_Next(lz->it);
+       assert(PyIter_Check(it));
+       item = (*it->ob_type->tp_iternext)(it);
        if (item == NULL)
                return NULL;
 
@@ -560,10 +564,12 @@ static PyObject *
 islice_next(isliceobject *lz)
 {
        PyObject *item;
+       PyObject *it = lz->it;
        long oldnext;
 
        while (lz->cnt < lz->next) {
-               item = PyIter_Next(lz->it);
+               assert(PyIter_Check(it));
+               item = (*it->ob_type->tp_iternext)(it);
                if (item == NULL)
                        return NULL;
                Py_DECREF(item);
@@ -571,7 +577,8 @@ islice_next(isliceobject *lz)
        }
        if (lz->cnt >= lz->stop)
                return NULL;
-       item = PyIter_Next(lz->it);
+       assert(PyIter_Check(it));
+       item = (*it->ob_type->tp_iternext)(it);
        if (item == NULL)
                return NULL;
        lz->cnt++;
@@ -715,8 +722,10 @@ starmap_next(starmapobject *lz)
 {
        PyObject *args;
        PyObject *result;
+       PyObject *it = lz->it;
 
-       args = PyIter_Next(lz->it);
+       assert(PyIter_Check(it));
+       args = (*it->ob_type->tp_iternext)(it);
        if (args == NULL)
                return NULL;
        if (!PyTuple_CheckExact(args)) {
@@ -1194,10 +1203,12 @@ static PyObject *
 ifilter_next(ifilterobject *lz)
 {
        PyObject *item;
+       PyObject *it = lz->it;
        long ok;
 
        for (;;) {
-               item = PyIter_Next(lz->it);
+               assert(PyIter_Check(it));
+               item = (*it->ob_type->tp_iternext)(it);
                if (item == NULL)
                        return NULL;
 
@@ -1348,10 +1359,12 @@ static PyObject *
 ifilterfalse_next(ifilterfalseobject *lz)
 {
        PyObject *item;
+       PyObject *it = lz->it;
        long ok;
 
        for (;;) {
-               item = PyIter_Next(lz->it);
+               assert(PyIter_Check(it));
+               item = (*it->ob_type->tp_iternext)(it);
                if (item == NULL)
                        return NULL;
 
@@ -1626,7 +1639,8 @@ izip_next(izipobject *lz)
        if (result->ob_refcnt == 1) {
                for (i=0 ; i < tuplesize ; i++) {
                        it = PyTuple_GET_ITEM(lz->ittuple, i);
-                       item = PyIter_Next(it);
+                       assert(PyIter_Check(it));
+                       item = (*it->ob_type->tp_iternext)(it);
                        if (item == NULL)
                                return NULL;
                        Py_DECREF(PyTuple_GET_ITEM(result, i));
@@ -1639,7 +1653,8 @@ izip_next(izipobject *lz)
                        return NULL;
                for (i=0 ; i < tuplesize ; i++) {
                        it = PyTuple_GET_ITEM(lz->ittuple, i);
-                       item = PyIter_Next(it);
+                       assert(PyIter_Check(it));
+                       item = (*it->ob_type->tp_iternext)(it);
                        if (item == NULL) {
                                Py_DECREF(result);
                                return NULL;