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import unittest
from ctypes import *
import _ctypes_test
lib = CDLL(_ctypes_test.__file__)
class StringPtrTestCase(unittest.TestCase):
def test__POINTER_c_char(self):
class X(Structure):
_fields_ = [("str", POINTER(c_char))]
x = X()
# NULL pointer access
self.assertRaises(ValueError, getattr, x.str, "contents")
b = c_buffer("Hello, World")
from sys import getrefcount as grc
self.assertEqual(grc(b), 2)
x.str = b
self.assertEqual(grc(b), 3)
# POINTER(c_char) and Python string is NOT compatible
# POINTER(c_char) and c_buffer() is compatible
for i in range(len(b)):
self.assertEqual(b[i], x.str[i])
self.assertRaises(TypeError, setattr, x, "str", "Hello, World")
def test__c_char_p(self):
class X(Structure):
_fields_ = [("str", c_char_p)]
x = X()
# c_char_p and Python string is compatible
# c_char_p and c_buffer is NOT compatible
self.assertEqual(x.str, None)
x.str = "Hello, World"
self.assertEqual(x.str, "Hello, World")
b = c_buffer("Hello, World")
self.assertRaises(TypeError, setattr, x, "str", b)
def test_functions(self):
strchr = lib.my_strchr
strchr.restype = c_char_p
# c_char_p and Python string is compatible
# c_char_p and c_buffer are now compatible
strchr.argtypes = c_char_p, c_char
self.assertEqual(strchr("abcdef", "c"), "cdef")
self.assertEqual(strchr(c_buffer("abcdef"), "c"), "cdef")
# POINTER(c_char) and Python string is NOT compatible
# POINTER(c_char) and c_buffer() is compatible
strchr.argtypes = POINTER(c_char), c_char
buf = c_buffer("abcdef")
self.assertEqual(strchr(buf, "c"), "cdef")
self.assertEqual(strchr("abcdef", "c"), "cdef")
# XXX These calls are dangerous, because the first argument
# to strchr is no longer valid after the function returns!
# So we must keep a reference to buf separately
strchr.restype = POINTER(c_char)
buf = c_buffer("abcdef")
r = strchr(buf, "c")
x = r[0], r[1], r[2], r[3], r[4]
self.assertEqual(x, ("c", "d", "e", "f", "\000"))
del buf
# x1 will NOT be the same as x, usually:
x1 = r[0], r[1], r[2], r[3], r[4]
if __name__ == '__main__':
unittest.main()
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