decoder: rephrase .has_channel() argument parse logic
authorGerhard Sittig <gerhard.sittig@gmx.net>
Sun, 17 Dec 2017 17:50:25 +0000 (18:50 +0100)
committerUwe Hermann <uwe@hermann-uwe.de>
Sat, 31 Mar 2018 18:44:21 +0000 (20:44 +0200)
Have the Python C API check the argument type and do the type conversion
already. Raise an IndexError exception when the range check fails.

type_decoder.c

index 0d2195135f5e591a3a127368eb9f8385734373fd..7c711323a508436c9027ef526f9f3c446c1451ff 100644 (file)
@@ -855,9 +855,8 @@ err:
  */
 static PyObject *Decoder_has_channel(PyObject *self, PyObject *args)
 {
-       int idx, max_idx;
+       int idx, count;
        struct srd_decoder_inst *di;
-       PyObject *py_channel;
        PyGILState_STATE gstate;
 
        if (!self || !args)
@@ -870,24 +869,20 @@ static PyObject *Decoder_has_channel(PyObject *self, PyObject *args)
                goto err;
        }
 
-       /* Parse the argument of self.has_channel() into 'py_channel'. */
-       if (!PyArg_ParseTuple(args, "O", &py_channel)) {
+       /*
+        * Get the integer argument of self.has_channel(). Check for
+        * the range of supported PD input channel numbers.
+        */
+       if (!PyArg_ParseTuple(args, "i", &idx)) {
                /* Let Python raise this exception. */
                goto err;
        }
 
-       if (!PyLong_Check(py_channel)) {
-               PyErr_SetString(PyExc_Exception, "channel index not a number");
-               goto err;
-       }
-
-       idx = PyLong_AsLong(py_channel);
-       max_idx = g_slist_length(di->decoder->channels)
-               + g_slist_length(di->decoder->opt_channels) - 1;
-
-       if (idx < 0 || idx > max_idx) {
-               srd_err("Invalid channel index %d/%d.", idx, max_idx);
-               PyErr_SetString(PyExc_Exception, "invalid channel");
+       count = g_slist_length(di->decoder->channels) +
+               g_slist_length(di->decoder->opt_channels);
+       if (idx < 0 || idx >= count) {
+               srd_err("Invalid index %d, PD channel count %d.", idx, count);
+               PyErr_SetString(PyExc_IndexError, "invalid channel index");
                goto err;
        }