Style fixes; make the conversion from unsigned long to long safe

mdickinson · mdickinson · commit e0375636ad48 · 2023-01-14T15:50:18.000Z
diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
@@ -183,30 +183,35 @@ static long compute_range_length_long(PyObject *start,
     int overflow = 0;
 
     long long_start = PyLong_AsLongAndOverflow(start, &overflow);
-    if (overflow)
+    if (overflow) {
         return -2;
-    if (long_start==-1 && PyErr_Occurred()) {
+    }
+    if (long_start == -1 && PyErr_Occurred()) {
         return -1;
     }
     long long_stop = PyLong_AsLongAndOverflow(stop, &overflow);
-    if (overflow)
+    if (overflow) {
         return -2;
-    if (long_stop==-1 && PyErr_Occurred()) {
+    }
+    if (long_stop == -1 && PyErr_Occurred()) {
         return -1;
     }
     long long_step = PyLong_AsLongAndOverflow(step, &overflow);
-    if (overflow)
+    if (overflow) {
         return -2;
-    if (long_step==-1 && PyErr_Occurred()) {
+    }
+    if (long_step == -1 && PyErr_Occurred()) {
         return -1;
     }
-    long len = get_len_of_range(long_start, long_stop, long_step);
 
-    if (len<0) {
-        /* we have an overflow */
-        len = -2;
+    unsigned long ulen = get_len_of_range(long_start, long_stop, long_step);
+    if (ulen > (unsigned long)LONG_MAX) {
+        /* length too large for a long */
+        return -2;
+    }
+    else {
+        return (long)ulen;
     }
-    return len;
 }
 
 /* Return number of items in range (lo, hi, step) as a PyLong object,
@@ -226,23 +231,23 @@ compute_range_length(PyObject *start, PyObject *stop, PyObject *step)
     PyObject *tmp1 = NULL, *tmp2 = NULL, *result;
                 /* holds sub-expression evaluations */
 
+    PyObject *zero = _PyLong_GetZero();  // borrowed reference
+    PyObject *one = _PyLong_GetOne();  // borrowed reference
+
     assert(PyLong_Check(start));
     assert(PyLong_Check(stop));
     assert(PyLong_Check(step));
 
     /* fast path when all arguments fit into a long integer */
     long len = compute_range_length_long(start, stop, step);
-    if (len>=0) {
+    if (len >= 0) {
         return PyLong_FromLong(len);
     }
-    else if (len==-1) {
+    else if (len == -1) {
         /* unexpected error from compute_range_length_long, we propagate to the caller */
         return NULL;
     }
-
-
-    PyObject *zero = _PyLong_GetZero();  // borrowed reference
-    PyObject *one = _PyLong_GetOne();  // borrowed reference
+    assert(len == -2);
 
     cmp_result = PyObject_RichCompareBool(step, zero, Py_GT);
     if (cmp_result == -1)
