diff --git a/Include/object.h b/Include/object.h
index ed6f3d1..faa3057 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -92,7 +92,8 @@
  */
 #define PyObject_VAR_HEAD		\
 	PyObject_HEAD			\
-	int ob_size; /* Number of items in variable part */
+	Py_ssize_t ob_size; /* Number of items in variable part */
+#define Py_INVALID_SIZE (Py_ssize_t)-1
 
 /* Nothing is actually declared to be a PyObject, but every pointer to
  * a Python object can be cast to a PyObject*.  This is inheritance built
@@ -127,16 +128,29 @@
 typedef PyObject * (*binaryfunc)(PyObject *, PyObject *);
 typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *);
 typedef int (*inquiry)(PyObject *);
+typedef Py_ssize_t (*lenfunc)(PyObject *);
 typedef int (*coercion)(PyObject **, PyObject **);
-typedef PyObject *(*intargfunc)(PyObject *, int);
-typedef PyObject *(*intintargfunc)(PyObject *, int, int);
+typedef PyObject *(*intargfunc)(PyObject *, int) Py_DEPRECATED(2.5);
+typedef PyObject *(*intintargfunc)(PyObject *, int, int) Py_DEPRECATED(2.5);
+typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t);
+typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t);
 typedef int(*intobjargproc)(PyObject *, int, PyObject *);
 typedef int(*intintobjargproc)(PyObject *, int, int, PyObject *);
+typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *);
+typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *);
 typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *);
+
+/* int-based buffer interface */
 typedef int (*getreadbufferproc)(PyObject *, int, void **);
 typedef int (*getwritebufferproc)(PyObject *, int, void **);
 typedef int (*getsegcountproc)(PyObject *, int *);
 typedef int (*getcharbufferproc)(PyObject *, int, const char **);
+/* ssize_t-based buffer interface */
+typedef Py_ssize_t (*readbufferproc)(PyObject *, Py_ssize_t, void **);
+typedef Py_ssize_t (*writebufferproc)(PyObject *, Py_ssize_t, void **);
+typedef Py_ssize_t (*segcountproc)(PyObject *, Py_ssize_t *);
+typedef Py_ssize_t (*charbufferproc)(PyObject *, Py_ssize_t, const char **);
+
 typedef int (*objobjproc)(PyObject *, PyObject *);
 typedef int (*visitproc)(PyObject *, void *);
 typedef int (*traverseproc)(PyObject *, visitproc, void *);
@@ -195,30 +209,30 @@
 } PyNumberMethods;
 
 typedef struct {
-	inquiry sq_length;
+	lenfunc sq_length;
 	binaryfunc sq_concat;
-	intargfunc sq_repeat;
-	intargfunc sq_item;
-	intintargfunc sq_slice;
-	intobjargproc sq_ass_item;
-	intintobjargproc sq_ass_slice;
+	ssizeargfunc sq_repeat;
+	ssizeargfunc sq_item;
+	ssizessizeargfunc sq_slice;
+	ssizeobjargproc sq_ass_item;
+	ssizessizeobjargproc sq_ass_slice;
 	objobjproc sq_contains;
 	/* Added in release 2.0 */
 	binaryfunc sq_inplace_concat;
-	intargfunc sq_inplace_repeat;
+	ssizeargfunc sq_inplace_repeat;
 } PySequenceMethods;
 
 typedef struct {
-	inquiry mp_length;
+	lenfunc mp_length;
 	binaryfunc mp_subscript;
 	objobjargproc mp_ass_subscript;
 } PyMappingMethods;
 
 typedef struct {
-	getreadbufferproc bf_getreadbuffer;
-	getwritebufferproc bf_getwritebuffer;
-	getsegcountproc bf_getsegcount;
-	getcharbufferproc bf_getcharbuffer;
+	readbufferproc bf_getreadbuffer;
+	writebufferproc bf_getwritebuffer;
+	segcountproc bf_getsegcount;
+	charbufferproc bf_getcharbuffer;
 } PyBufferProcs;
 
 
@@ -239,7 +253,7 @@
 typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *);
 typedef int (*initproc)(PyObject *, PyObject *, PyObject *);
 typedef PyObject *(*newfunc)(struct _typeobject *, PyObject *, PyObject *);
-typedef PyObject *(*allocfunc)(struct _typeobject *, int);
+typedef PyObject *(*allocfunc)(struct _typeobject *, Py_ssize_t);
 
 typedef struct _typeobject {
 	PyObject_VAR_HEAD
@@ -362,7 +376,7 @@
 #define PyType_CheckExact(op) ((op)->ob_type == &PyType_Type)
 
 PyAPI_FUNC(int) PyType_Ready(PyTypeObject *);
-PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, int);
+PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t);
 PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *,
 					       PyObject *, PyObject *);
 PyAPI_FUNC(PyObject *) _PyType_Lookup(PyTypeObject *, PyObject *);