diff -r fa4a44afda12 Lib/test/test_memoryview.py
--- a/Lib/test/test_memoryview.py	Tue Aug 19 08:38:12 2008 +0200
+++ b/Lib/test/test_memoryview.py	Tue Aug 19 16:23:25 2008 +0200
@@ -5,8 +5,132 @@
 
 import unittest
 import test.support
+import sys
 
-class MemoryviewTest(unittest.TestCase):
+
+class CommonMemoryTests:
+    #
+    # Tests common to direct memoryviews and sliced memoryviews
+    #
+
+    base_object = b"abcdef"
+
+    def _test_getitem_with_type(self, tp):
+        b = tp(self.base_object)
+        oldrefcount = sys.getrefcount(b)
+        m = self._view(b)
+        self.assertEquals(m[0], b"a")
+        self.assert_(isinstance(m[0], bytearray), type(m[0]))
+        self.assertEquals(m[5], b"f")
+        self.assertEquals(m[-1], b"f")
+        self.assertEquals(m[-6], b"a")
+        # Bounds checking
+        self.assertRaises(IndexError, lambda: m[6])
+        self.assertRaises(IndexError, lambda: m[-7])
+        self.assertRaises(IndexError, lambda: m[sys.maxsize])
+        self.assertRaises(IndexError, lambda: m[-sys.maxsize])
+        # Type checking
+        self.assertRaises(TypeError, lambda: m[None])
+        self.assertRaises(TypeError, lambda: m[0.0])
+        self.assertRaises(TypeError, lambda: m["a"])
+        m = None
+        self.assertEquals(sys.getrefcount(b), oldrefcount)
+    
+    def test_getitem_readonly(self):
+        self._test_getitem_with_type(bytes)
+
+    def test_getitem_writable(self):
+        self._test_getitem_with_type(bytearray)
+
+    def test_setitem_readonly(self):
+        b = self.base_object
+        oldrefcount = sys.getrefcount(b)
+        m = self._view(b)
+        def setitem(value):
+            m[0] = value
+        self.assertRaises(TypeError, setitem, b"a")
+        self.assertRaises(TypeError, setitem, 65)
+        self.assertRaises(TypeError, setitem, memoryview(b"a"))
+        m = None
+        self.assertEquals(sys.getrefcount(b), oldrefcount)
+
+    def test_setitem_writable(self):
+        b = bytearray(self.base_object)
+        oldrefcount = sys.getrefcount(b)
+        m = self._view(b)
+        m[0] = b"0"
+        self._check_contents(b, b"0bcdef")
+        m[1:3] = b"12"
+        self._check_contents(b, b"012def")
+        m[1:1] = b""
+        self._check_contents(b, b"012def")
+        m[:] = b"abcdef"
+        self._check_contents(b, b"abcdef")
+
+        # Overlapping copies of a view into itself
+        m[0:3] = m[2:5]
+        self._check_contents(b, b"cdedef")
+        m[:] = b"abcdef"
+        m[2:5] = m[0:3]
+        self._check_contents(b, b"ababcf")
+
+        def setitem(key, value):
+            m[key] = value
+        # Bounds checking
+        self.assertRaises(IndexError, setitem, 6, b"a")
+        self.assertRaises(IndexError, setitem, -7, b"a")
+        self.assertRaises(IndexError, setitem, sys.maxsize, b"a")
+        self.assertRaises(IndexError, setitem, -sys.maxsize, b"a")
+        # Wrong index/slice types
+        self.assertRaises(TypeError, setitem, 0.0, b"a")
+        self.assertRaises(TypeError, setitem, (0,), b"a")
+        self.assertRaises(TypeError, setitem, "a", b"a")
+        # Trying to resize the memory object
+        self.assertRaises(ValueError, setitem, 0, b"")
+        self.assertRaises(ValueError, setitem, 0, b"ab")
+        self.assertRaises(ValueError, setitem, slice(1,1), b"a")
+        self.assertRaises(ValueError, setitem, slice(0,2), b"a")
+
+        m = None
+        self.assertEquals(sys.getrefcount(b), oldrefcount)
+
+    def test_len(self):
+        self.assertEquals(len(self._view(self.base_object)), 6)
+
+    def test_tobytes(self):
+        m = self._view(self.base_object)
+        b = m.tobytes()
+        self.assertEquals(b, b"abcdef")
+        self.assert_(isinstance(b, bytearray), type(b))
+
+    def _test_attributes_with_type(self, tp):
+        b = tp(self.base_object)
+        m = self._view(b)
+        self.assertEquals(m.format, 'B')
+        self.assertEquals(m.itemsize, 1)
+        self.assertEquals(m.ndim, 1)
+        self.assertEquals(m.shape, (6,))
+        self.assertEquals(m.size, 6)
+        self.assertEquals(m.strides, (1,))
+        self.assertEquals(m.suboffsets, None)
+        return m
+
+    def test_attributes_readonly(self):
+        m = self._test_attributes_with_type(bytes)
+        self.assertEquals(m.readonly, True)
+
+    def test_attributes_writable(self):
+        m = self._test_attributes_with_type(bytearray)
+        self.assertEquals(m.readonly, False)
+
+
+class MemoryviewTest(unittest.TestCase, CommonMemoryTests):
+
+    def _view(self, obj):
+        return memoryview(obj)
+
+    def _check_contents(self, obj, contents):
+        self.assertEquals(obj, contents)
 
     def test_constructor(self):
         ob = b'test'
@@ -17,8 +141,38 @@
         self.assertRaises(TypeError, memoryview, argument=ob)
         self.assertRaises(TypeError, memoryview, ob, argument=True)
 
+
+class MemorySliceTest(unittest.TestCase, CommonMemoryTests):
+    base_object = b"XabcdefY"
+
+    def _view(self, obj):
+        m = memoryview(obj)
+        return m[1:7]
+
+    def _check_contents(self, obj, contents):
+        self.assertEquals(obj[1:7], contents)
+
+    def test_refs(self):
+        m = memoryview(b"ab")
+        oldrefcount = sys.getrefcount(m)
+        m[1:2]
+        self.assertEquals(sys.getrefcount(m), oldrefcount)
+
+
+class MemorySliceSliceTest(unittest.TestCase, CommonMemoryTests):
+    base_object = b"XabcdefY"
+
+    def _view(self, obj):
+        m = memoryview(obj)
+        return m[:7][1:]
+
+    def _check_contents(self, obj, contents):
+        self.assertEquals(obj[1:7], contents)
+
+
 def test_main():
-    test.support.run_unittest(MemoryviewTest)
+    test.support.run_unittest(
+        MemoryviewTest, MemorySliceTest, MemorySliceSliceTest)
 
 
 if __name__ == "__main__":
diff -r fa4a44afda12 Objects/memoryobject.c
--- a/Objects/memoryobject.c	Tue Aug 19 08:38:12 2008 +0200
+++ b/Objects/memoryobject.c	Tue Aug 19 16:23:25 2008 +0200
@@ -13,8 +13,8 @@
 	}
 	if (self->view.obj == NULL)
 		return 0;
-        return self->view.obj->ob_type->tp_as_buffer->bf_getbuffer(self->base, NULL,
-                                                               PyBUF_FULL);
+        return self->view.obj->ob_type->tp_as_buffer->bf_getbuffer(
+            self->view.obj, NULL, PyBUF_FULL);
 }
 
 static void
@@ -37,9 +37,14 @@
 						   &PyMemoryView_Type);
 	if (mview == NULL) return NULL;
 	mview->base = NULL;
+        /* XXX there should be an API to duplicate a buffer object */
 	mview->view = *info;
-	if (info->obj)
-		Py_INCREF(mview->view.obj);
+        if (info->shape == &(info->len))
+            mview->view.shape = &(mview->view.len);
+        if (info->strides == &(info->itemsize))
+            mview->view.strides = &(mview->view.itemsize);
+        /* NOTE: mview->view.obj should already have been incref'ed as
+           part of PyBuffer_FillInfo(). */
 	return (PyObject *)mview;
 }
 
@@ -412,7 +417,7 @@
 memory_dealloc(PyMemoryViewObject *self)
 {
         if (self->view.obj != NULL) {
-            if (PyTuple_Check(self->base)) {
+            if (self->base && PyTuple_Check(self->base)) {
                 /* Special case when first element is generic object
                    with buffer interface and the second element is a
                    contiguous "shadow" that must be copied back into
@@ -511,7 +516,7 @@
 			if (result < 0) {
 				result += view->shape[0];
 			}
-			if ((result < 0) || (result > view->shape[0])) {
+			if ((result < 0) || (result >= view->shape[0])) {
 				PyErr_SetString(PyExc_IndexError,
 						"index out of bounds");
 				return NULL;
@@ -537,10 +542,39 @@
 			return PyMemoryView_FromMemory(&newview);
 		}
 	}
+	else if (PySlice_Check(key)) {
+		Py_ssize_t start, stop, step, slicelength;
 
-	/* Need to support getting a sliced view */
-        Py_INCREF(Py_NotImplemented);
-        return Py_NotImplemented;
+		if (PySlice_GetIndicesEx((PySliceObject*)key, self->view.len,
+				 &start, &stop, &step, &slicelength) < 0) {
+			return NULL;
+		}
+
+		if (step == 1 && view->ndim == 1) {
+                    Py_buffer newview;
+                    void *newbuf = (char *) self->view.buf
+                                + start * self->view.itemsize;
+                    int newflags = self->view.readonly
+                        ? PyBUF_CONTIG_RO : PyBUF_CONTIG;
+
+                    /* XXX There should be an API to create a subbuffer */
+                    if (PyObject_GetBuffer(self->view.obj,
+                            &newview, newflags) == -1)
+                        return NULL;
+                    newview.buf = newbuf;
+                    newview.len = slicelength;
+                    newview.format = self->view.format;
+                    newview.shape = &(newview.len);
+                    if (view->strides == &(view->itemsize))
+                        newview.strides = &(newview.itemsize);
+                    return PyMemoryView_FromMemory(&newview);
+		}
+                PyErr_SetNone(PyExc_NotImplementedError);
+	}
+        PyErr_Format(PyExc_TypeError,
+            "cannot index memory using \"%.200s\"", 
+            key->ob_type->tp_name);
+        return NULL;
 }
 
 
@@ -548,7 +582,93 @@
 static int
 memory_ass_sub(PyMemoryViewObject *self, PyObject *key, PyObject *value)
 {
-        return 0;
+    Py_ssize_t start, len, bytelen, i;
+    Py_buffer srcview;
+    Py_buffer *view = &(self->view);
+    char *srcbuf, *destbuf;
+
+    if (view->readonly) {
+        PyErr_SetString(PyExc_TypeError,
+            "cannot modify read-only memory");
+        return -1;
+    }
+    if (view->ndim != 1) {
+        PyErr_SetNone(PyExc_NotImplementedError);
+        return -1;
+    }
+    if (PyIndex_Check(key)) {
+        start = PyNumber_AsSsize_t(key, NULL);
+        if (start == -1 && PyErr_Occurred())
+            return -1;
+        if (start < 0) {
+            start += view->shape[0];
+        }
+        if ((start < 0) || (start >= view->shape[0])) {
+            PyErr_SetString(PyExc_IndexError,
+                            "index out of bounds");
+            return -1;
+        }
+        len = 1;
+    }
+    else if (PySlice_Check(key)) {
+        Py_ssize_t stop, step;
+
+        if (PySlice_GetIndicesEx((PySliceObject*)key, view->len,
+                         &start, &stop, &step, &len) < 0) {
+            return -1;
+        }
+        if (step != 1) {
+            PyErr_SetNone(PyExc_NotImplementedError);
+            return -1;
+        }
+    }
+    else {
+        PyErr_Format(PyExc_TypeError,
+            "cannot index memory using \"%.200s\"", 
+            key->ob_type->tp_name);
+        return -1;
+    }
+    if (PyObject_GetBuffer(value, &srcview, PyBUF_CONTIG_RO) == -1) {
+        return -1;
+    }
+    /* XXX should we allow assignment of different item sizes
+       as long as the byte length is the same?
+       (e.g. assign 2 shorts to a 4-byte slice) */
+    if (srcview.itemsize != view->itemsize) {
+        PyErr_Format(PyExc_TypeError,
+            "mismatching item sizes for \"%.200s\" and \"%.200s\"", 
+            view->obj->ob_type->tp_name, srcview.obj->ob_type->tp_name);
+        goto on_error;
+    }
+    if (srcview.len != len) {
+        PyErr_SetString(PyExc_ValueError,
+            "cannot modify size of memoryview object");
+        goto on_error;
+    }
+    /* Do the actual copy */
+    destbuf = (char *) view->buf + start * view->itemsize;
+    srcbuf = (char *) srcview.buf;
+    bytelen = len * view->itemsize;
+    if (destbuf + bytelen < srcbuf || srcbuf + bytelen < destbuf)
+        /* No overlapping */
+        memcpy(destbuf, srcbuf, bytelen);
+    else if (destbuf < srcbuf) {
+        /* Copy in ascending order */
+        for (i = 0; i < bytelen; i++)
+            destbuf[i] = srcbuf[i];
+    }
+    else {
+        /* Copy in descencing order */
+        for (i = bytelen - 1; i >= 0; i--)
+            destbuf[i] = srcbuf[i];
+    }
+
+    PyBuffer_Release(&srcview);
+    return 0;
+
+on_error:
+    PyBuffer_Release(&srcview);
+    return -1;
 }
 
 /* As mapping */