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from ctypes import *
from ctypes.test import need_symbol
import unittest
import sys
class Test(unittest.TestCase):
def test_array2pointer(self):
array = (c_int * 3)(42, 17, 2)
# casting an array to a pointer works.
ptr = cast(array, POINTER(c_int))
self.assertEqual([ptr[i] for i in range(3)], [42, 17, 2])
if 2*sizeof(c_short) == sizeof(c_int):
ptr = cast(array, POINTER(c_short))
if sys.byteorder == "little":
self.assertEqual([ptr[i] for i in range(6)],
[42, 0, 17, 0, 2, 0])
else:
self.assertEqual([ptr[i] for i in range(6)],
[0, 42, 0, 17, 0, 2])
def test_address2pointer(self):
array = (c_int * 3)(42, 17, 2)
address = addressof(array)
ptr = cast(c_void_p(address), POINTER(c_int))
self.assertEqual([ptr[i] for i in range(3)], [42, 17, 2])
ptr = cast(address, POINTER(c_int))
self.assertEqual([ptr[i] for i in range(3)], [42, 17, 2])
def test_p2a_objects(self):
array = (c_char_p * 5)()
self.assertEqual(array._objects, None)
array[0] = b"foo bar"
self.assertEqual(array._objects, {'0': b"foo bar"})
p = cast(array, POINTER(c_char_p))
# array and p share a common _objects attribute
self.assertIs(p._objects, array._objects)
self.assertEqual(array._objects, {'0': b"foo bar", id(array): array})
p[0] = b"spam spam"
self.assertEqual(p._objects, {'0': b"spam spam", id(array): array})
self.assertIs(array._objects, p._objects)
p[1] = b"foo bar"
self.assertEqual(p._objects, {'1': b'foo bar', '0': b"spam spam", id(array): array})
self.assertIs(array._objects, p._objects)
def test_other(self):
p = cast((c_int * 4)(1, 2, 3, 4), POINTER(c_int))
self.assertEqual(p[:4], [1,2, 3, 4])
self.assertEqual(p[:4:], [1, 2, 3, 4])
self.assertEqual(p[3:-1:-1], [4, 3, 2, 1])
self.assertEqual(p[:4:3], [1, 4])
c_int()
self.assertEqual(p[:4], [1, 2, 3, 4])
self.assertEqual(p[:4:], [1, 2, 3, 4])
self.assertEqual(p[3:-1:-1], [4, 3, 2, 1])
self.assertEqual(p[:4:3], [1, 4])
p[2] = 96
self.assertEqual(p[:4], [1, 2, 96, 4])
self.assertEqual(p[:4:], [1, 2, 96, 4])
self.assertEqual(p[3:-1:-1], [4, 96, 2, 1])
self.assertEqual(p[:4:3], [1, 4])
c_int()
self.assertEqual(p[:4], [1, 2, 96, 4])
self.assertEqual(p[:4:], [1, 2, 96, 4])
self.assertEqual(p[3:-1:-1], [4, 96, 2, 1])
self.assertEqual(p[:4:3], [1, 4])
def test_char_p(self):
# This didn't work: bad argument to internal function
s = c_char_p(b"hiho")
self.assertEqual(cast(cast(s, c_void_p), c_char_p).value,
b"hiho")
@need_symbol('c_wchar_p')
def test_wchar_p(self):
s = c_wchar_p("hiho")
self.assertEqual(cast(cast(s, c_void_p), c_wchar_p).value,
"hiho")
def test_bad_type_arg(self):
# The type argument must be a ctypes pointer type.
array_type = c_byte * sizeof(c_int)
array = array_type()
self.assertRaises(TypeError, cast, array, None)
self.assertRaises(TypeError, cast, array, array_type)
class Struct(Structure):
_fields_ = [("a", c_int)]
self.assertRaises(TypeError, cast, array, Struct)
class MyUnion(Union):
_fields_ = [("a", c_int)]
self.assertRaises(TypeError, cast, array, MyUnion)
if __name__ == "__main__":
unittest.main()
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