Add additional check for calling setinputsizes() with an empty dictionary in

order to avoid the error "cx_Oracle.ProgrammingError: positional and named
binds cannot be intermixed"
(https://github.com/oracle/python-cx_Oracle/issues/199).

src/cxoCursor.c

@@ -1743,16 +1743,23 @@ static PyObject *cxoCursor_setInputSizes(cxoCursor *cursor, PyObject *args,
 
     // eliminate existing bind variables
     Py_CLEAR(cursor->bindVariables);
+
+    // if no values passed, do nothing further, but return an empty list or
+    // dictionary as appropriate
+    if (numKeywordArgs == 0 && numPositionalArgs == 0) {
+        if (keywordArgs)
+            return PyDict_New();
+        return PyList_New(0);
+    }
+
+    // retain bind variables
+    cursor->setInputSizes = 1;
     if (numKeywordArgs > 0)
         cursor->bindVariables = PyDict_New();
     else cursor->bindVariables = PyList_New(numPositionalArgs);
     if (!cursor->bindVariables)
         return NULL;
 
-    // retain bind variables if any were set
-    if (numKeywordArgs > 0 || numPositionalArgs > 0)
-        cursor->setInputSizes = 1;
-
     // process each input
     if (numKeywordArgs > 0) {
         i = 0;

test/Cursor.py

@@ -538,6 +538,22 @@ class TestCursor(BaseTestCase):
         self.cursor.execute("select :val from dual", val = "Test Value")
         self.assertEqual(self.cursor.fetchall(), [("Test Value",)])
 
+    def testSetInputSizesEmptyDict(self):
+        "test setting input sizes with an empty dictionary"
+        emptyDict = {}
+        self.cursor.prepare("select 236 from dual")
+        self.cursor.setinputsizes(**emptyDict)
+        self.cursor.execute(None, emptyDict)
+        self.assertEqual(self.cursor.fetchall(), [(236,)])
+
+    def testSetInputSizesEmptyList(self):
+        "test setting input sizes with an empty list"
+        emptyList = {}
+        self.cursor.prepare("select 239 from dual")
+        self.cursor.setinputsizes(*emptyList)
+        self.cursor.execute(None, emptyList)
+        self.assertEqual(self.cursor.fetchall(), [(239,)])
+
     def testSetInputSizesByPosition(self):
         """test setting input sizes with positional args"""
         var = self.cursor.var(cx_Oracle.STRING, 100)