def test_allocate_invalid_size(self):
# Checks that attempting to allocate too big a region fails gracefully.
size = types.size_t.maxval // 8 // 2
for pred in (True, False):
with self.assertRaises(MemoryError) as raises:
rtsys.meminfo_alloc(size, safe=pred)
self.assertIn(f"Requested allocation of {size} bytes failed.",
str(raises.exception))
def test_allocate_negative_size(self):
# Checks that attempting to allocate negative number of bytes fails
# gracefully.
size = -10
for pred in (True, False):
with self.assertRaises(ValueError) as raises:
rtsys.meminfo_alloc(size, safe=pred)
msg = f"Cannot allocate a negative number of bytes: {size}."
self.assertIn(msg, str(raises.exception))
def test_buffer(self):
from ctypes import c_uint32, c_void_p, POINTER, cast
dtype = np.dtype(np.uint32)
bytesize = dtype.itemsize * 10
mi = rtsys.meminfo_alloc(bytesize, safe=True)
self.assertEqual(mi.refcount, 1)
addr = mi.data
c_arr = cast(c_void_p(addr), POINTER(c_uint32 * 10))
# Check 0xCB-filling
for i in range(10):
self.assertEqual(c_arr.contents[i], 0xcbcbcbcb)
# Init array with ctypes
for i in range(10):
c_arr.contents[i] = i + 1
arr = np.ndarray(dtype=dtype,
shape=bytesize // dtype.itemsize,
buffer=mi)
self.assertEqual(mi.refcount, 1)
del mi
# Modify array with NumPy
np.testing.assert_equal(np.arange(arr.size) + 1, arr)
arr += 1
# Check value reflected in ctypes
for i in range(10):
self.assertEqual(c_arr.contents[i], i + 2)
self.assertEqual(arr.ctypes.data, addr)
del arr
def test_memoryview(self):
from ctypes import c_uint32, c_void_p, POINTER, cast
dtype = np.dtype(np.uint32)
bytesize = dtype.itemsize * 10
mi = rtsys.meminfo_alloc(bytesize, safe=True)
addr = mi.data
c_arr = cast(c_void_p(mi.data), POINTER(c_uint32 * 10))
# Check 0xCB-filling
for i in range(10):
self.assertEqual(c_arr.contents[i], 0xcbcbcbcb)
# Init array with ctypes
for i in range(10):
c_arr.contents[i] = i + 1
mview = memoryview(mi)
self.assertEqual(mview.nbytes, bytesize)
self.assertFalse(mview.readonly)
self.assertIs(mi, mview.obj)
self.assertTrue(mview.c_contiguous)
self.assertEqual(mview.itemsize, 1)
self.assertEqual(mview.ndim, 1)
del mi
arr = np.ndarray(dtype=dtype,
shape=mview.nbytes // dtype.itemsize,
buffer=mview)
del mview
# Modify array with NumPy
np.testing.assert_equal(np.arange(arr.size) + 1, arr)
arr += 1
# Check value reflected in ctypes
for i in range(10):
self.assertEqual(c_arr.contents[i], i + 2)
self.assertEqual(arr.ctypes.data, addr)
del arr