def test_convert_memoryview(self):
a = b'World is hell!'
a_refcount = sys.getrefcount(a)
b = containers.StridedArrayView1D(a)
b_refcount = sys.getrefcount(b)
self.assertEqual(sys.getrefcount(a), a_refcount + 1)
c = memoryview(b)
self.assertEqual(c.ndim, 1)
self.assertEqual(len(c), len(a))
self.assertEqual(bytes(c), a)
# Unlike slicing, StridedArrayView's buffer protocol returns a
# reference to itself and not the underlying buffer -- it needs to be
# kept around because the Py_buffer refers to its internals for size.
# Also returning a reference to the underlying buffer would mean the
# underlying buffer's releasebuffer function gets called instead of
# ours which is *not* wanted.
self.assertIs(c.obj, b)
self.assertEqual(sys.getrefcount(b), b_refcount + 1)
self.assertEqual(sys.getrefcount(a), a_refcount + 1)
with self.assertRaisesRegex(TypeError,
"cannot modify read-only memory"):
c[-1] = ord('?')
def test_init_buffer_memoryview_obj(self):
a = b'hello'
v = memoryview(a)
b = containers.StridedArrayView1D(v)
# memoryview's buffer protocol returns itself, not the underlying
# bytes, as it manages the Py_buffer instance. So this is expected.
self.assertIs(b.owner, v)
def test_init_buffer(self):
a = b'hello'
a_refcount = sys.getrefcount(a)
b = containers.StridedArrayView1D(a)
self.assertIs(b.owner, a)
self.assertEqual(len(b), 5)
self.assertEqual(bytes(b), b'hello')
self.assertEqual(b.size, (5, ))
self.assertEqual(b.stride, (1, ))
self.assertEqual(b[2], 'l')
self.assertEqual(sys.getrefcount(a), a_refcount + 1)
# Not mutable
with self.assertRaisesRegex(TypeError,
"object does not support item assignment"):
b[4] = '!'
# b should keep a reference to a, so deleting the local reference
# shouldn't affect it
del a
self.assertTrue(sys.getrefcount(b.owner), a_refcount)
self.assertEqual(b[2], 'l')
# Now, if we delete b, a should not be referenced by anything anymore
a = b.owner
del b
self.assertTrue(sys.getrefcount(a), a_refcount)
def test_init_buffer_empty(self):
a = b''
a_refcount = sys.getrefcount(a)
b = containers.StridedArrayView1D(a)
self.assertIs(b.owner, None)
self.assertEqual(len(b), 0)
self.assertEqual(sys.getrefcount(a), a_refcount)
def test_init_buffer_stride(self):
a = memoryview(b'hello')[::2]
self.assertEqual(bytes(a), b'hlo')
b = containers.StridedArrayView1D(a)
self.assertEqual(len(b), 3)
self.assertEqual(bytes(b), b'hlo')
self.assertEqual(b.size, (3, ))
self.assertEqual(b.stride, (2, ))
self.assertEqual(b[2], 'o')
def test_slice_empty(self):
data = b'hello'
data_refcount = sys.getrefcount(data)
# slice.start = slice.stop
a = containers.StridedArrayView1D(data)[7:8]
self.assertEqual(a.size, (0, ))
# Empty view, original data not referenced at all
self.assertIs(a.owner, None)
self.assertEqual(sys.getrefcount(data), data_refcount)
def test_slice_stride_negative(self):
a = b'World_ _i_s_ _hell!'
b = containers.StridedArrayView1D(a)
# Check consistency with slices on bytes
c1 = a[-5:3:-2] # like [4:-4:2] above, but reverted
c2 = b[-5:3:-2]
self.assertEqual(len(c1), 6)
self.assertEqual(len(c2), 6)
self.assertEqual(bytes(c1), b'h si d') # like b'd is h' but reverted
self.assertEqual(bytes(c2), b'h si d')
self.assertEqual(c2.size, (6, ))
self.assertEqual(c2.stride, (-2, ))
def test_slice_stride(self):
a = b'World_ _i_s_ _hell!'
b = containers.StridedArrayView1D(a)
# Check consistency with slices on bytes
c1 = a[4:-4:2]
c2 = b[4:-4:2]
self.assertIsInstance(c2, containers.StridedArrayView1D)
self.assertEqual(len(c1), 6)
self.assertEqual(len(c2), 6)
self.assertEqual(bytes(c1), b'd is h')
self.assertEqual(bytes(c2), b'd is h')
self.assertEqual(c2.size, (6, ))
self.assertEqual(c2.stride, (2, ))
def test_init(self):
a = containers.StridedArrayView1D()
b = containers.MutableStridedArrayView1D()
self.assertIs(a.owner, None)
self.assertIs(b.owner, None)
self.assertEqual(len(a), 0)
self.assertEqual(len(b), 0)
self.assertEqual(bytes(a), b'')
self.assertEqual(bytes(b), b'')
self.assertEqual(a.size, (0, ))
self.assertEqual(b.size, (0, ))
self.assertEqual(a.stride, (0, ))
self.assertEqual(b.stride, (0, ))
self.assertEqual(a.dimensions, 1)
self.assertEqual(b.dimensions, 1)
def test_slice(self):
a = b'World is hell!'
a_refcount = sys.getrefcount(a)
b = containers.StridedArrayView1D(a)
b_refcount = sys.getrefcount(b)
self.assertIs(b.owner, a)
self.assertEqual(sys.getrefcount(a), a_refcount + 1)
# When slicing, b's refcount should not change but a's refcount should
# increase
c = b[4:-4]
self.assertEqual(c.size, (6, ))
self.assertEqual(c.stride, (1, ))
self.assertIs(c.owner, a)
self.assertIsInstance(c, containers.StridedArrayView1D)
self.assertEqual(bytes(c), b'd is h')
self.assertEqual(sys.getrefcount(b), b_refcount)
self.assertEqual(sys.getrefcount(a), a_refcount + 2)
# Deleting a slice should reduce a's refcount again, keep b's unchanged
del c
self.assertEqual(sys.getrefcount(b), b_refcount)
self.assertEqual(sys.getrefcount(a), a_refcount + 1)
def test_slice_invalid(self):
with self.assertRaisesRegex(ValueError, "slice step cannot be zero"):
containers.StridedArrayView1D()[-5:3:0]
def test_slice_invalid(self):
with self.assertRaisesRegex(TypeError, "indices must be integers"):
containers.StridedArrayView1D()[-5:3:"boo"]
def test_init_buffer_unexpected_dimensions(self):
a = memoryview(b'123456').cast('b', shape=[2, 3])
self.assertEqual(bytes(a), b'123456')
with self.assertRaisesRegex(BufferError,
"expected 1 dimensions but got 2"):
b = containers.StridedArrayView1D(a)
