--- Modules/mmapmodule.c.~1~	2008-08-19 10:47:13.000000000 -0700
+++ Modules/mmapmodule.c	2008-12-17 00:12:31.000000000 -0800
@@ -85,12 +85,24 @@
 	ACCESS_COPY
 } access_mode;
 
+/* Our very own off_t-like type, 64-bit if possible */
+/* copied from Objects/fileobject.c */
+#if !defined(HAVE_LARGEFILE_SUPPORT)
+typedef off_t Py_off_t;
+#elif SIZEOF_OFF_T >= 8
+typedef off_t Py_off_t;
+#elif SIZEOF_FPOS_T >= 8
+typedef fpos_t Py_off_t;
+#else
+#error "Large file support, but neither off_t nor fpos_t is large enough."
+#endif
+
 typedef struct {
 	PyObject_HEAD
 	char *	data;
 	size_t	size;
 	size_t	pos;    /* relative to offset */
-	size_t	offset; 
+	Py_off_t offset; 
 
 #ifdef MS_WINDOWS
 	HANDLE	map_handle;
@@ -1078,7 +1090,8 @@
 #endif
 	mmap_object *m_obj;
 	PyObject *map_size_obj = NULL, *offset_obj = NULL;
-	Py_ssize_t map_size, offset;
+	Py_ssize_t map_size;
+	Py_off_t offset;
 	int fd, flags = MAP_SHARED, prot = PROT_WRITE | PROT_READ;
 	int devzero = -1;
 	int access = (int)ACCESS_DEFAULT;
@@ -1093,7 +1106,20 @@
 	map_size = _GetMapSize(map_size_obj, "size");
 	if (map_size < 0)
 		return NULL;
-        offset = _GetMapSize(offset_obj, "offset");
+	if (offset_obj == Py_None || offset_obj == NULL) {
+                offset = 0;
+        }
+        else {
+#if !defined(HAVE_LARGEFILE_SUPPORT)
+		offset = PyInt_AsLong(offset_obj);
+#else
+		offset = PyLong_Check(offset_obj) ?
+			PyLong_AsLongLong(offset_obj) :
+			PyInt_AsLong(offset_obj);
+#endif
+		if (PyErr_Occurred())
+			return NULL;
+        }
         if (offset < 0)
                 return NULL;
 
@@ -1136,7 +1162,7 @@
 	if (fd != -1 && fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) {
 		if (map_size == 0) {
 			map_size = st.st_size;
-		} else if ((size_t)offset + (size_t)map_size > st.st_size) {
+		} else if (offset + map_size > st.st_size) {
 			PyErr_SetString(PyExc_ValueError,
 					"mmap length is greater than file size");
 			return NULL;