Lib/ctypes/test/test_frombuffer.py

   1 from ctypes import *
   2 import array
   3 import gc
   4 import unittest
   5
   6 class X(Structure):
   7     _fields_ = [("c_int", c_int)]
   8     init_called = False
   9     def __init__(self):
  10         self._init_called = True
  11
  12 class Test(unittest.TestCase):
  13     def test_fom_buffer(self):
  14         a = array.array("i", range(16))
  15         x = (c_int * 16).from_buffer(a)
  16
  17         y = X.from_buffer(a)
  18         self.assertEqual(y.c_int, a[0])
  19         self.assertFalse(y.init_called)
  20
  21         self.assertEqual(x[:], a.tolist())
  22
  23         a[0], a[-1] = 200, -200
  24         self.assertEqual(x[:], a.tolist())
  25
  26         self.assertTrue(a in x._objects.values())
  27
  28         self.assertRaises(ValueError,
  29                           c_int.from_buffer, a, -1)
  30
  31         expected = x[:]
  32         del a; gc.collect(); gc.collect(); gc.collect()
  33         self.assertEqual(x[:], expected)
  34
  35         self.assertRaises(TypeError,
  36                           (c_char * 16).from_buffer, "a" * 16)
  37
  38     def test_fom_buffer_with_offset(self):
  39         a = array.array("i", range(16))
  40         x = (c_int * 15).from_buffer(a, sizeof(c_int))
  41
  42         self.assertEqual(x[:], a.tolist()[1:])
  43         self.assertRaises(ValueError, lambda: (c_int * 16).from_buffer(a, sizeof(c_int)))
  44         self.assertRaises(ValueError, lambda: (c_int * 1).from_buffer(a, 16 * sizeof(c_int)))
  45
  46     def test_from_buffer_copy(self):
  47         a = array.array("i", range(16))
  48         x = (c_int * 16).from_buffer_copy(a)
  49
  50         y = X.from_buffer_copy(a)
  51         self.assertEqual(y.c_int, a[0])
  52         self.assertFalse(y.init_called)
  53
  54         self.assertEqual(x[:], range(16))
  55
  56         a[0], a[-1] = 200, -200
  57         self.assertEqual(x[:], range(16))
  58
  59         self.assertEqual(x._objects, None)
  60
  61         self.assertRaises(ValueError,
  62                           c_int.from_buffer, a, -1)
  63
  64         del a; gc.collect(); gc.collect(); gc.collect()
  65         self.assertEqual(x[:], range(16))
  66
  67         x = (c_char * 16).from_buffer_copy("a" * 16)
  68         self.assertEqual(x[:], "a" * 16)
  69
  70     def test_fom_buffer_copy_with_offset(self):
  71         a = array.array("i", range(16))
  72         x = (c_int * 15).from_buffer_copy(a, sizeof(c_int))
  73
  74         self.assertEqual(x[:], a.tolist()[1:])
  75         self.assertRaises(ValueError,
  76                           (c_int * 16).from_buffer_copy, a, sizeof(c_int))
  77         self.assertRaises(ValueError,
  78                           (c_int * 1).from_buffer_copy, a, 16 * sizeof(c_int))
  79
  80 if __name__ == '__main__':
  81     unittest.main()