Merged revisions 79843-79844 via svnmerge from

mdickinson · mdickinson · commit 3318d29d2202 · 2010-04-06T16:53:17.000Z
svn+ssh://pythondev@svn.python.org/python/trunk ........ r79843 | mark.dickinson | 2010-04-06 17:46:09 +0100 (Tue, 06 Apr 2010) | 4 lines Issue #8259: Get rid of 'outrageous left shift count' error when left-shifting an integer by more than 2**31 on a 64-bit machine. Also convert shift counts to a Py_ssize_t instead of a C long. ........ r79844 | mark.dickinson | 2010-04-06 17:47:55 +0100 (Tue, 06 Apr 2010) | 1 line Misc/NEWS entry for r79843. ........
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -12,6 +12,10 @@ What's New in Python 3.2 Alpha 1?
 Core and Builtins
 -----------------
 
+- Issue #8259: 1L << (2**31) no longer produces an 'outrageous shift error'
+  on 64-bit machines.  The shift count for either left or right shift is
+  permitted to be up to sys.maxsize.
+
 - Ensure that tokenization of identifiers is not affected by locale.
 
 - Issue #1222585: Added LDCXXSHARED for C++ support. Patch by Arfrever.
diff --git a/Objects/longobject.c b/Objects/longobject.c
@@ -3779,8 +3779,7 @@ static PyObject *
 long_rshift(PyLongObject *a, PyLongObject *b)
 {
 	PyLongObject *z = NULL;
-	long shiftby;
-	Py_ssize_t newsize, wordshift, loshift, hishift, i, j;
+	Py_ssize_t shiftby, newsize, wordshift, loshift, hishift, i, j;
 	digit lomask, himask;
 
 	CHECK_BINOP(a, b);
@@ -3799,8 +3798,7 @@ long_rshift(PyLongObject *a, PyLongObject *b)
 		Py_DECREF(a2);
 	}
 	else {
-
-		shiftby = PyLong_AsLong((PyObject *)b);
+		shiftby = PyLong_AsSsize_t((PyObject *)b);
 		if (shiftby == -1L && PyErr_Occurred())
 			goto rshift_error;
 		if (shiftby < 0) {
@@ -3841,27 +3839,21 @@ long_lshift(PyObject *v, PyObject *w)
 	PyLongObject *a = (PyLongObject*)v;
 	PyLongObject *b = (PyLongObject*)w;
 	PyLongObject *z = NULL;
-	long shiftby;
-	Py_ssize_t oldsize, newsize, wordshift, remshift, i, j;
+	Py_ssize_t shiftby, oldsize, newsize, wordshift, remshift, i, j;
 	twodigits accum;
 
 	CHECK_BINOP(a, b);
 
-	shiftby = PyLong_AsLong((PyObject *)b);
+	shiftby = PyLong_AsSsize_t((PyObject *)b);
 	if (shiftby == -1L && PyErr_Occurred())
 		goto lshift_error;
 	if (shiftby < 0) {
 		PyErr_SetString(PyExc_ValueError, "negative shift count");
 		goto lshift_error;
 	}
-	if ((long)(int)shiftby != shiftby) {
-		PyErr_SetString(PyExc_ValueError,
-				"outrageous left shift count");
-		goto lshift_error;
-	}
 	/* wordshift, remshift = divmod(shiftby, PyLong_SHIFT) */
-	wordshift = (int)shiftby / PyLong_SHIFT;
-	remshift  = (int)shiftby - wordshift * PyLong_SHIFT;
+	wordshift = shiftby / PyLong_SHIFT;
+	remshift  = shiftby - wordshift * PyLong_SHIFT;
 
 	oldsize = ABS(Py_SIZE(a));
 	newsize = oldsize + wordshift;
