Use dictionary specific looping idiom where possible.

Simplifies and speeds-up the code.

diff --git a/Objects/setobject.c b/Objects/setobject.c
index 8e70546a2ada9e5248e2f816c3085c3145ae1f20..cc8d25c645a92932cce3def3029fd52d9588d243 100644 (file)
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -369,7 +369,9 @@ static PyObject *
 set_difference(PySetObject *so, PyObject *other)
 {
        PySetObject *result, *otherset=NULL;
-       PyObject *item, *otherdata, *tgtdata, *it;
+       PyObject *otherdata, *tgtdata;
+       PyObject *key, *value;
+       int pos = 0;
 
        result = (PySetObject *)make_new_set(so->ob_type, NULL);
        if (result == NULL)
@@ -389,30 +391,15 @@ set_difference(PySetObject *so, PyObject *other)
                otherdata = otherset->data;
        }       
 
-       it = PyObject_GetIter(so->data);
-       if (it == NULL) {
-               Py_XDECREF(otherset);
-               Py_DECREF(result);
-               return NULL;
-       }
-
-       while ((item = PyIter_Next(it)) != NULL) {
-               if (!PyDict_Contains(otherdata, item)) {
-                       if (PyDict_SetItem(tgtdata, item, Py_True) == -1) {
+       while (PyDict_Next(so->data, &pos, &key, &value)) {
+               if (!PyDict_Contains(otherdata, key)) {
+                       if (PyDict_SetItem(tgtdata, key, Py_True) == -1) {
                                Py_XDECREF(otherset);
-                               Py_DECREF(it);
-                               Py_DECREF(item);
                                return NULL;
                        }
                }
-               Py_DECREF(item);
        }
-       Py_DECREF(it);
        Py_XDECREF(otherset);
-       if (PyErr_Occurred()) {
-               Py_DECREF(result);
-               return NULL;
-       }
        return (PyObject *)result;
 }
 
@@ -482,11 +469,12 @@ set_isub(PySetObject *so, PyObject *other)
 static PyObject *
 set_symmetric_difference_update(PySetObject *so, PyObject *other)
 {
-       PyObject *item, *selfdata, *it, *otherdata;
+       PyObject *selfdata, *otherdata;
        PySetObject *otherset = NULL;
+       PyObject *key, *value;
+       int pos = 0;
 
        selfdata = so->data;
-
        if (PyDict_Check(other))
                otherdata = other;
        else if (PyAnySet_Check(other))
@@ -498,32 +486,20 @@ set_symmetric_difference_update(PySetObject *so, PyObject *other)
                otherdata = otherset->data;
        }
 
-       it = PyObject_GetIter(otherdata);
-       if (it == NULL)
-               return NULL;
-
-       while ((item = PyIter_Next(it)) != NULL) {
-               if (PyDict_Contains(selfdata, item)) {
-                       if (PyDict_DelItem(selfdata, item) == -1) {
+       while (PyDict_Next(otherdata, &pos, &key, &value)) {
+               if (PyDict_Contains(selfdata, key)) {
+                       if (PyDict_DelItem(selfdata, key) == -1) {
                                Py_XDECREF(otherset);
-                               Py_DECREF(it);
-                               Py_DECREF(item);
                                return NULL;
                        }
                } else {
-                       if (PyDict_SetItem(selfdata, item, Py_True) == -1) {
+                       if (PyDict_SetItem(selfdata, key, Py_True) == -1) {
                                Py_XDECREF(otherset);
-                               Py_DECREF(it);
-                               Py_DECREF(item);
                                return NULL;
                        }
                }
-               Py_DECREF(item);
        }
        Py_XDECREF(otherset);
-       Py_DECREF(it);
-       if (PyErr_Occurred())
-               return NULL;
        Py_RETURN_NONE;
 }
 
@@ -534,7 +510,9 @@ static PyObject *
 set_symmetric_difference(PySetObject *so, PyObject *other)
 {
        PySetObject *result;
-       PyObject *item, *selfdata, *otherdata, *tgtdata, *it, *rv, *otherset;
+       PyObject *selfdata, *otherdata, *tgtdata, *rv, *otherset;
+       PyObject *key, *value;
+       int pos = 0;
 
        if (PyDict_Check(other))
                otherdata = other;
@@ -557,46 +535,23 @@ set_symmetric_difference(PySetObject *so, PyObject *other)
        tgtdata = result->data;
        selfdata = so->data;
 
-       it = PyObject_GetIter(otherdata);
-       if (it == NULL) {
-               Py_DECREF(result);
-               return NULL;
-       }
-       while ((item = PyIter_Next(it)) != NULL) {
-               if (!PyDict_Contains(selfdata, item)) {
-                       if (PyDict_SetItem(tgtdata, item, Py_True) == -1) {
-                               Py_DECREF(it);
-                               Py_DECREF(item);
+       while (PyDict_Next(otherdata, &pos, &key, &value)) {
+               if (!PyDict_Contains(selfdata, key)) {
+                       if (PyDict_SetItem(tgtdata, key, Py_True) == -1) {
+                               Py_DECREF(result);
                                return NULL;
                        }
                }
-               Py_DECREF(item);
-       }
-       Py_DECREF(it);
-       if (PyErr_Occurred()) {
-               Py_DECREF(result);
-               return NULL;
        }
 
-       it = PyObject_GetIter(selfdata);
-       if (it == NULL) {
-               Py_DECREF(result);
-               return NULL;
-       }
-       while ((item = PyIter_Next(it)) != NULL) {
-               if (!PyDict_Contains(otherdata, item)) {
-                       if (PyDict_SetItem(tgtdata, item, Py_True) == -1) {
-                               Py_DECREF(it);
-                               Py_DECREF(item);
+       pos = 0;
+       while (PyDict_Next(selfdata, &pos, &key, &value)) {
+               if (!PyDict_Contains(otherdata, key)) {
+                       if (PyDict_SetItem(tgtdata, key, Py_True) == -1) {
+                               Py_DECREF(result);
                                return NULL;
                        }
                }
-               Py_DECREF(item);
-       }
-       Py_DECREF(it);
-       if (PyErr_Occurred()) {
-               Py_DECREF(result);
-               return NULL;
        }
 
        return (PyObject *)result;
@@ -637,7 +592,9 @@ set_ixor(PySetObject *so, PyObject *other)
 static PyObject *
 set_issubset(PySetObject *so, PyObject *other)
 {
-       PyObject *otherdata, *it, *item, *tmp, *result;
+       PyObject *otherdata, *tmp, *result;
+       PyObject *key, *value;
+       int pos = 0;
 
        if (!PyAnySet_Check(other)) {
                tmp = make_new_set(&PySet_Type, other);
@@ -649,23 +606,12 @@ set_issubset(PySetObject *so, PyObject *other)
        }
        if (set_len(so) > set_len((PySetObject *)other)) 
                Py_RETURN_FALSE;
-       
-       it = PyObject_GetIter(so->data);
-       if (it == NULL)
-               return NULL;
 
        otherdata = ((PySetObject *)other)->data;
-       while ((item = PyIter_Next(it)) != NULL) {
-               if (!PyDict_Contains(otherdata, item)) {
-                       Py_DECREF(it);
-                       Py_DECREF(item);
+       while (PyDict_Next(((PySetObject *)so)->data, &pos, &key, &value)) {
+               if (!PyDict_Contains(otherdata, key))
                        Py_RETURN_FALSE;
-               }
-               Py_DECREF(item);
        }
-       Py_DECREF(it);
-       if (PyErr_Occurred()) 
-               return NULL;
        Py_RETURN_TRUE;
 }
 
@@ -706,29 +652,22 @@ set_nocmp(PyObject *self)
 static long
 frozenset_hash(PyObject *self)
 {
-       PyObject *it, *item;
        PySetObject *so = (PySetObject *)self;
-       long hash = 0;
+       PyObject *key, *value;
+       int pos = 0;
 
+       long hash = 0;
        if (so->hash != -1)
                return so->hash;
-               
-       it = PyObject_GetIter(((PySetObject *)so)->data);
-       if (it == NULL) 
-               return -1;
 
-       while ((item = PyIter_Next(it)) != NULL) {
+       while (PyDict_Next(so->data, &pos, &key, &value)) {
                /* Multiplying by a large prime increases the bit dispersion for
                   closely spaced hash values.  The is important because some
                   use cases have many combinations of a small number of 
                   elements with nearby hashes so that many distinct combinations
                   collapse to only a handful of distinct hash values. */
-               hash ^= PyObject_Hash(item) * 3644798167u;
-               Py_DECREF(item);
+               hash ^= PyObject_Hash(key) * 3644798167u;
        }
-       Py_DECREF(it);
-       if (PyErr_Occurred()) 
-               return -1;
        so->hash = hash;
        return hash;
 }
@@ -788,30 +727,17 @@ set_repr(PySetObject *so)
 static int
 set_tp_print(PySetObject *so, FILE *fp, int flags)
 {
-       PyObject *it, *item;
-       int firstpass=1;
+       PyObject *key, *value;
+       int pos = 0;
 
-       it = PyObject_GetIter(so->data);
-       if (it == NULL)
-               return -1;
        fprintf(fp, "%s([", so->ob_type->tp_name);
-
-       while ((item = PyIter_Next(it)) != NULL) {
-               if (firstpass == 1)
-                       firstpass = 0;
-               else
+       while (PyDict_Next(so->data, &pos, &key, &value)) {
+               if (pos)
                        fprintf(fp, ", ");
-               if (PyObject_Print(item, fp, 0) != 0) {
-                       Py_DECREF(it);
-                       Py_DECREF(item);
+               if (PyObject_Print(key, fp, 0) != 0)
                        return -1;
-               }
-               Py_DECREF(item);
        }
-       Py_DECREF(it);
        fprintf(fp, "])");
-       if (PyErr_Occurred()) 
-               return -1;
        return 0;
 }