test_prototypes.py revision 04349c602c9dfc70b2d451a8191b21d7f30db3e6 
1from ctypes import *
2from ctypes.test import need_symbol
3import unittest
4
5# IMPORTANT INFO:
6#
7# Consider this call:
8#    func.restype = c_char_p
9#    func(c_char_p("123"))
10# It returns
11#    "123"
12#
13# WHY IS THIS SO?
14#
15# argument tuple (c_char_p("123"), ) is destroyed after the function
16# func is called, but NOT before the result is actually built.
17#
18# If the arglist would be destroyed BEFORE the result has been built,
19# the c_char_p("123") object would already have a zero refcount,
20# and the pointer passed to (and returned by) the function would
21# probably point to deallocated space.
22#
23# In this case, there would have to be an additional reference to the argument...
24
25import _ctypes_test
26testdll = CDLL(_ctypes_test.__file__)
27
28# Return machine address `a` as a (possibly long) non-negative integer.
29# Starting with Python 2.5, id(anything) is always non-negative, and
30# the ctypes addressof() inherits that via PyLong_FromVoidPtr().
31def positive_address(a):
32    if a >= 0:
33        return a
34    # View the bits in `a` as unsigned instead.
35    import struct
36    num_bits = struct.calcsize("P") * 8 # num bits in native machine address
37    a += 1L << num_bits
38    assert a >= 0
39    return a
40
41def c_wbuffer(init):
42    n = len(init) + 1
43    return (c_wchar * n)(*init)
44
45class CharPointersTestCase(unittest.TestCase):
46
47    def setUp(self):
48        func = testdll._testfunc_p_p
49        func.restype = c_long
50        func.argtypes = None
51
52    def test_paramflags(self):
53        # function returns c_void_p result,
54        # and has a required parameter named 'input'
55        prototype = CFUNCTYPE(c_void_p, c_void_p)
56        func = prototype(("_testfunc_p_p", testdll),
57                         ((1, "input"),))
58
59        try:
60            func()
61        except TypeError, details:
62            self.assertEqual(str(details), "required argument 'input' missing")
63        else:
64            self.fail("TypeError not raised")
65
66        self.assertEqual(func(None), None)
67        self.assertEqual(func(input=None), None)
68
69
70    def test_int_pointer_arg(self):
71        func = testdll._testfunc_p_p
72        func.restype = c_long
73        self.assertEqual(0, func(0))
74
75        ci = c_int(0)
76
77        func.argtypes = POINTER(c_int),
78        self.assertEqual(positive_address(addressof(ci)),
79                             positive_address(func(byref(ci))))
80
81        func.argtypes = c_char_p,
82        self.assertRaises(ArgumentError, func, byref(ci))
83
84        func.argtypes = POINTER(c_short),
85        self.assertRaises(ArgumentError, func, byref(ci))
86
87        func.argtypes = POINTER(c_double),
88        self.assertRaises(ArgumentError, func, byref(ci))
89
90    def test_POINTER_c_char_arg(self):
91        func = testdll._testfunc_p_p
92        func.restype = c_char_p
93        func.argtypes = POINTER(c_char),
94
95        self.assertEqual(None, func(None))
96        self.assertEqual("123", func("123"))
97        self.assertEqual(None, func(c_char_p(None)))
98        self.assertEqual("123", func(c_char_p("123")))
99
100        self.assertEqual("123", func(c_buffer("123")))
101        ca = c_char("a")
102        self.assertEqual("a", func(pointer(ca))[0])
103        self.assertEqual("a", func(byref(ca))[0])
104
105    def test_c_char_p_arg(self):
106        func = testdll._testfunc_p_p
107        func.restype = c_char_p
108        func.argtypes = c_char_p,
109
110        self.assertEqual(None, func(None))
111        self.assertEqual("123", func("123"))
112        self.assertEqual(None, func(c_char_p(None)))
113        self.assertEqual("123", func(c_char_p("123")))
114
115        self.assertEqual("123", func(c_buffer("123")))
116        ca = c_char("a")
117        self.assertEqual("a", func(pointer(ca))[0])
118        self.assertEqual("a", func(byref(ca))[0])
119
120    def test_c_void_p_arg(self):
121        func = testdll._testfunc_p_p
122        func.restype = c_char_p
123        func.argtypes = c_void_p,
124
125        self.assertEqual(None, func(None))
126        self.assertEqual("123", func("123"))
127        self.assertEqual("123", func(c_char_p("123")))
128        self.assertEqual(None, func(c_char_p(None)))
129
130        self.assertEqual("123", func(c_buffer("123")))
131        ca = c_char("a")
132        self.assertEqual("a", func(pointer(ca))[0])
133        self.assertEqual("a", func(byref(ca))[0])
134
135        func(byref(c_int()))
136        func(pointer(c_int()))
137        func((c_int * 3)())
138
139    @need_symbol('c_wchar_p')
140    def test_c_void_p_arg_with_c_wchar_p(self):
141        func = testdll._testfunc_p_p
142        func.restype = c_wchar_p
143        func.argtypes = c_void_p,
144
145        self.assertEqual(None, func(c_wchar_p(None)))
146        self.assertEqual(u"123", func(c_wchar_p(u"123")))
147
148    def test_instance(self):
149        func = testdll._testfunc_p_p
150        func.restype = c_void_p
151
152        class X:
153            _as_parameter_ = None
154
155        func.argtypes = c_void_p,
156        self.assertEqual(None, func(X()))
157
158        func.argtypes = None
159        self.assertEqual(None, func(X()))
160
161@need_symbol('c_wchar')
162class WCharPointersTestCase(unittest.TestCase):
163
164    def setUp(self):
165        func = testdll._testfunc_p_p
166        func.restype = c_int
167        func.argtypes = None
168
169
170    def test_POINTER_c_wchar_arg(self):
171        func = testdll._testfunc_p_p
172        func.restype = c_wchar_p
173        func.argtypes = POINTER(c_wchar),
174
175        self.assertEqual(None, func(None))
176        self.assertEqual(u"123", func(u"123"))
177        self.assertEqual(None, func(c_wchar_p(None)))
178        self.assertEqual(u"123", func(c_wchar_p(u"123")))
179
180        self.assertEqual(u"123", func(c_wbuffer(u"123")))
181        ca = c_wchar("a")
182        self.assertEqual(u"a", func(pointer(ca))[0])
183        self.assertEqual(u"a", func(byref(ca))[0])
184
185    def test_c_wchar_p_arg(self):
186        func = testdll._testfunc_p_p
187        func.restype = c_wchar_p
188        func.argtypes = c_wchar_p,
189
190        c_wchar_p.from_param(u"123")
191
192        self.assertEqual(None, func(None))
193        self.assertEqual("123", func(u"123"))
194        self.assertEqual(None, func(c_wchar_p(None)))
195        self.assertEqual("123", func(c_wchar_p("123")))
196
197        # XXX Currently, these raise TypeErrors, although they shouldn't:
198        self.assertEqual("123", func(c_wbuffer("123")))
199        ca = c_wchar("a")
200        self.assertEqual("a", func(pointer(ca))[0])
201        self.assertEqual("a", func(byref(ca))[0])
202
203class ArrayTest(unittest.TestCase):
204    def test(self):
205        func = testdll._testfunc_ai8
206        func.restype = POINTER(c_int)
207        func.argtypes = c_int * 8,
208
209        func((c_int * 8)(1, 2, 3, 4, 5, 6, 7, 8))
210
211        # This did crash before:
212
213        def func(): pass
214        CFUNCTYPE(None, c_int * 3)(func)
215
216################################################################
217
218if __name__ == '__main__':
219    unittest.main()
220