Paul McGuire

1318a1319,1507
> static PyObject *
> builtin_minmax(PyObject *self, PyObject *args, PyObject *kwds)
> {
>   const char *name = "minmax";
>   PyObject *v, *it, *item, *val, *item2, *val2, *minitem, *minval, *maxitem, *maxval, *keyfunc=NULL;
>   PyObject *result = NULL;
>   int seqlen, cmp;
>
>   if (PyTuple_Size(args) > 1)
>       v = args;
>   else if (!PyArg_UnpackTuple(args, (char *)name, 1, 1, &v))
>       return NULL;
>
>   if (kwds != NULL && PyDict_Check(kwds) && PyDict_Size(kwds)) {
>       keyfunc = PyDict_GetItemString(kwds, "key");
>       if (PyDict_Size(kwds)!=1  ||  keyfunc == NULL) {
>           PyErr_Format(PyExc_TypeError,
>               "%s() got an unexpected keyword argument", name);
>           return NULL;
>       }
>       Py_INCREF(keyfunc);
>   }
>
>   it = PyObject_GetIter(v);
>   if (it == NULL) {
>       Py_XDECREF(keyfunc);
>       return NULL;
>   }
>
>   minitem = NULL; /* the results */
>   maxitem = NULL;
>   minval = NULL;  /* the values associated with the results */
>   maxval = NULL;
>
>   /* initialize min and max returns with the first item in the list */
>   item = PyIter_Next(it);
>   if (item == NULL)
>   {
>       //minitem = Py_None;
>       //Py_INCREF(minitem);
>       //maxitem = Py_None;
>       //Py_INCREF(maxitem);
>       goto EarlyExit_short_sequence;
>   }
>
>   if (keyfunc != NULL) {
>       val = PyObject_CallFunctionObjArgs(keyfunc, item, NULL);
>       if (val == NULL)
>           goto Fail_it_item;
>   }
>   /* no key function; the value is the item */
>   else {
>       val = item;
>       // increment twice, as we will assign to both min and max return vals
>       Py_INCREF(val);
>       Py_INCREF(val);
>   }
>
>   minitem = item;
>   minval = val;
>   maxitem = item; /* the result */
>   maxval = val;  /* the value associated with the result */
>
>   seqlen = PySequence_Length(v);
>
>   // if even length sequence, put iter back at 0, to safely read by pairs
>   if (seqlen % 2 == 0) {
>       it = PyObject_GetIter(v);
>   }
>
>   // read by pairs
>   while (( item = PyIter_Next(it) ) && (item2 = PyIter_Next(it))) {
>
>       /* get the value from the key function */
>       if (keyfunc != NULL) {
>           val  = PyObject_CallFunctionObjArgs(keyfunc, item, NULL);
>           val2 = PyObject_CallFunctionObjArgs(keyfunc, item2, NULL);
>           if (val == NULL || val2 == NULL)
>               goto Fail_it_item;
>       }
>       /* no key function; the value is the item */
>       else {
>           val = item;
>           Py_INCREF(val);
>           val2 = item2;
>           Py_INCREF(val2);
>       }
>
>
>       /*
>         if a > b:
>             a,b = b,a
>       */
>       cmp = PyObject_RichCompareBool(val, val2, Py_GT);
>       if (cmp < 0)
>           goto Fail_it_item_and_val;
>       else if (cmp > 0) {
>           PyObject* tmp;
>           tmp = val;  val  = val2;  val2  = tmp;
>           tmp = item; item = item2; item2 = tmp;
>       }
>
>       /*
>         if a < min_:
>             min_ = a
>       */
>       cmp = PyObject_RichCompareBool(val, minval, Py_LT);
>       if (cmp < 0)
>           goto Fail_it_item_and_val;
>       else if (cmp > 0) {
>           Py_DECREF(minval);
>           Py_DECREF(minitem);
>           minval = val;
>           minitem = item;
>       }
>       else {
>           Py_DECREF(item);
>           Py_DECREF(val);
>       }
>
>       /*
>         if b > max_:
>             max_ = b
>       */
>       cmp = PyObject_RichCompareBool(val2, maxval, Py_GT);
>       if (cmp < 0)
>           goto Fail_it_item_and_val;
>       else if (cmp > 0) {
>           Py_DECREF(maxval);
>           Py_DECREF(maxitem);
>           maxval = val2;
>           maxitem = item2;
>       }
>       else {
>           Py_DECREF(item2);
>           Py_DECREF(val2);
>       }
>   }
>   if (PyErr_Occurred())
>       goto Fail_it;
>
> EarlyExit_short_sequence:
>   if (maxval == NULL) {
>       PyErr_Format(PyExc_ValueError,
>                "%s() arg is an empty sequence", name);
>       assert(maxitem == NULL);
>   }
>   else {
>       Py_DECREF(maxval);
>       Py_DECREF(minval);
>   }
>   Py_DECREF(it);
>   Py_XDECREF(keyfunc);
>
>   if (maxitem != NULL) {
>       result = PyTuple_Pack(2, minitem, maxitem);
>       Py_DECREF(minitem);
>       Py_DECREF(maxitem);
>   }
>   else {
>       result = NULL;
>   }
>
>   return result;
>
> Fail_it_item_and_val:
>   Py_DECREF(val);
>   Py_DECREF(val2);
> Fail_it_item:
>   Py_DECREF(item);
>   Py_DECREF(item2);
> Fail_it:
>   Py_XDECREF(minval);
>   Py_XDECREF(minitem);
>   Py_XDECREF(maxval);
>   Py_XDECREF(maxitem);
>   Py_DECREF(it);
>   Py_XDECREF(keyfunc);
>   return NULL;
> }
>
> PyDoc_STRVAR(minmax_doc,
> "minmax(iterable[, key=func]) -> value\n\
> minmax(a, b, c, ...[, key=func]) -> value\n\
> \n\
> With a single iterable argument, return its smallest and largest items.\n\
> With two or more arguments, return the smallest and largest arguments.");
>
>
2265a2455
>   {"minmax",      (PyCFunction)builtin_minmax,        METH_VARARGS | METH_KEYWORDS, minmax_doc},