예제 #1
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 def test_getfield_setfield_unsigned_types(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     maxlong = sys.maxint
     if sys.platform == 'win32':
         maxlong = 2147483647
     fields = [
         Field('ubyte', types.ubyte),
         Field('ushort', types.ushort),
         Field('uint', types.uint),
         Field('ulong', types.ulong),
         Field('char', types.char),
         Field('unichar', types.unichar),
         Field('ptr', types.void_p),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('ubyte', -1)
     assert struct.getfield('ubyte') == 255
     struct.setfield('ushort', -1)
     assert struct.getfield('ushort') == 65535
     struct.setfield('uint', 43)
     assert struct.getfield('uint') == 43
     struct.setfield('ulong', -1)
     assert struct.getfield('ulong') == maxlong * 2 + 1
     struct.setfield('ulong', maxlong * 2 + 2)
     assert struct.getfield('ulong') == 0
     struct.setfield('char', b'a')
     assert struct.getfield('char') == b'a'
     struct.setfield('unichar', u'\u1234')
     assert struct.getfield('unichar') == u'\u1234'
     struct.setfield('ptr', -1)
     assert struct.getfield('ptr') == sys.maxint * 2 + 1
예제 #2
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_getfield_setfield_unsigned_types(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('ubyte', types.ubyte),
         Field('ushort', types.ushort),
         Field('uint', types.uint),
         Field('ulong', types.ulong),
         Field('char', types.char),
         Field('unichar', types.unichar),
         Field('ptr', types.void_p),
         ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('ubyte', -1)
     assert struct.getfield('ubyte') == 255
     struct.setfield('ushort', -1)
     assert struct.getfield('ushort') == 65535
     struct.setfield('uint', 43)
     assert struct.getfield('uint') == 43
     struct.setfield('ulong', -1)
     assert struct.getfield('ulong') == sys.maxsize*2 + 1
     struct.setfield('ulong', sys.maxsize*2 + 2)
     assert struct.getfield('ulong') == 0
     struct.setfield('char', 'a')
     assert struct.getfield('char') == 'a'
     struct.setfield('unichar', '\u1234')
     assert struct.getfield('unichar') == '\u1234'
     struct.setfield('ptr', -1)
     assert struct.getfield('ptr') == sys.maxsize*2 + 1
예제 #3
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 def test_getfield_setfield_unsigned_types(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('ubyte', types.ubyte),
         Field('ushort', types.ushort),
         Field('uint', types.uint),
         Field('ulong', types.ulong),
         Field('char', types.char),
         Field('unichar', types.unichar),
         Field('ptr', types.void_p),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('ubyte', -1)
     assert struct.getfield('ubyte') == 255
     struct.setfield('ushort', -1)
     assert struct.getfield('ushort') == 65535
     struct.setfield('uint', 43)
     assert struct.getfield('uint') == 43
     struct.setfield('ulong', -1)
     assert struct.getfield('ulong') == sys.maxsize * 2 + 1
     struct.setfield('ulong', sys.maxsize * 2 + 2)
     assert struct.getfield('ulong') == 0
     struct.setfield('char', b'a')
     assert struct.getfield('char') == b'a'
     struct.setfield('unichar', u'\u1234')
     assert struct.getfield('unichar') == u'\u1234'
     struct.setfield('ptr', -1)
     assert struct.getfield('ptr') == sys.maxsize * 2 + 1
예제 #4
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파일: app_struct.py 프로젝트: Darriall/pypy
 def _compute_shape(cls, name, dic):
     fields = dic.get('_fields_')
     if fields is None:
         return
     struct_descr = alt._StructDescr(name, fields)
     for field in fields:
         dic[field.name] = field
     dic['_struct_'] = struct_descr
예제 #5
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 def _compute_shape(cls, name, dic):
     fields = dic.get('_fields_')
     if fields is None:
         return
     struct_descr = alt._StructDescr(name, fields)
     for field in fields:
         dic[field.name] = field
     dic['_struct_'] = struct_descr
예제 #6
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test__StructDescr(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
         ]
     descr = _StructDescr('foo', fields)
     assert descr.ffitype.sizeof() == longsize*2
     assert descr.ffitype.name == 'struct foo'
예제 #7
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 def test__StructDescr(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
     ]
     descr = _StructDescr('foo', fields)
     assert descr.ffitype.sizeof() == longsize * 2
     assert descr.ffitype.name == 'struct foo'
예제 #8
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_unknown_type(self):
     if self.runappdirect:
         skip('cannot use self.dummy_type with -A')
     from _rawffi.alt import _StructDescr, Field
     fields = [
         Field('x', self.dummy_type),
         ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     raises(TypeError, "struct.getfield('x')")
     raises(TypeError, "struct.setfield('x', 42)")
예제 #9
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 def test_missing_field(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     raises(AttributeError, "struct.getfield('missing')")
     raises(AttributeError, "struct.setfield('missing', 42)")
예제 #10
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 def test_alignment(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.sbyte),
         Field('y', types.slong),
     ]
     descr = _StructDescr('foo', fields)
     assert descr.ffitype.sizeof() == longsize * 2
     assert fields[0].offset == 0
     assert fields[1].offset == longsize  # aligned to WORD
예제 #11
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_missing_field(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
         ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     raises(AttributeError, "struct.getfield('missing')")
     raises(AttributeError, "struct.setfield('missing', 42)")
예제 #12
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 def test_unknown_type(self):
     if self.runappdirect:
         skip('cannot use self.dummy_type with -A')
     from _rawffi.alt import _StructDescr, Field
     fields = [
         Field('x', self.dummy_type),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     raises(TypeError, "struct.getfield('x')")
     raises(TypeError, "struct.setfield('x', 42)")
예제 #13
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_alignment(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.sbyte),
         Field('y', types.slong),
         ]
     descr = _StructDescr('foo', fields)
     assert descr.ffitype.sizeof() == longsize*2
     assert fields[0].offset == 0
     assert fields[1].offset == longsize # aligned to WORD
예제 #14
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        def main():
            from _rawffi.alt import _StructDescr, Field, types

            fields = [Field("x", types.slong)]
            descr = _StructDescr("foo", fields)
            struct = descr.allocate()
            i = 0
            while i < 300:
                x = struct.getfield("x")  # ID: getfield
                x = x + 1
                struct.setfield("x", x)  # ID: setfield
                i += 1
            return struct.getfield("x")
예제 #15
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 def test_getfield_setfield_float(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.double),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('x', 123.4)
     assert struct.getfield('x') == 123.4
     mem = self.read_raw_mem(struct.getaddr(), 'c_double', 1)
     assert mem == [123.4]
예제 #16
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_getfield_setfield_float(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.double),
         ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('x', 123.4)
     assert struct.getfield('x') == 123.4
     mem = self.read_raw_mem(struct.getaddr(), 'c_double', 1)
     assert mem == [123.4]
예제 #17
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 def main():
     from _rawffi.alt import _StructDescr, Field, types
     fields = [
         Field('x', types.slong),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     i = 0
     while i < 300:
         x = struct.getfield('x')  # ID: getfield
         x = x + 1
         struct.setfield('x', x)  # ID: setfield
         i += 1
     return struct.getfield('x')
예제 #18
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 def test_nested_structure(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     foo_fields = [
         Field('x', types.slong),
         Field('y', types.slong),
     ]
     foo_descr = _StructDescr('foo', foo_fields)
     #
     bar_fields = [
         Field('x', types.slong),
         Field('foo', foo_descr.ffitype),
     ]
     bar_descr = _StructDescr('bar', bar_fields)
     assert bar_descr.ffitype.sizeof() == longsize * 3
     #
     struct = bar_descr.allocate()
     struct.setfield('x', 40)
     # reading a nested structure yields a reference to it
     struct_foo = struct.getfield('foo')
     struct_foo.setfield('x', 41)
     struct_foo.setfield('y', 42)
     mem = self.read_raw_mem(struct.getaddr(), 'c_long', 3)
     assert mem == [40, 41, 42]
     #
     struct_foo2 = foo_descr.allocate()
     struct_foo2.setfield('x', 141)
     struct_foo2.setfield('y', 142)
     # writing a nested structure copies its memory into the target
     struct.setfield('foo', struct_foo2)
     struct_foo2.setfield('x', 241)
     struct_foo2.setfield('y', 242)
     mem = self.read_raw_mem(struct.getaddr(), 'c_long', 3)
     assert mem == [40, 141, 142]
     mem = self.read_raw_mem(struct_foo2.getaddr(), 'c_long', 2)
     assert mem == [241, 242]
예제 #19
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_getfield_setfield(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
         ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('x', 42)
     struct.setfield('y', 43)
     assert struct.getfield('x') == 42
     assert struct.getfield('y') == 43
     mem = self.read_raw_mem(struct.getaddr(), 'c_long', 2)
     assert mem == [42, 43]
예제 #20
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_nested_structure(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     foo_fields = [
         Field('x', types.slong),
         Field('y', types.slong),
         ]
     foo_descr = _StructDescr('foo', foo_fields)
     #
     bar_fields = [
         Field('x', types.slong),
         Field('foo', foo_descr.ffitype),
         ]
     bar_descr = _StructDescr('bar', bar_fields)
     assert bar_descr.ffitype.sizeof() == longsize*3
     #
     struct = bar_descr.allocate()
     struct.setfield('x', 40)
     # reading a nested structure yields a reference to it
     struct_foo = struct.getfield('foo')
     struct_foo.setfield('x', 41)
     struct_foo.setfield('y', 42)
     mem = self.read_raw_mem(struct.getaddr(), 'c_long', 3)
     assert mem == [40, 41, 42]
     #
     struct_foo2 = foo_descr.allocate()
     struct_foo2.setfield('x', 141)
     struct_foo2.setfield('y', 142)
     # writing a nested structure copies its memory into the target
     struct.setfield('foo', struct_foo2)
     struct_foo2.setfield('x', 241)
     struct_foo2.setfield('y', 242)
     mem = self.read_raw_mem(struct.getaddr(), 'c_long', 3)
     assert mem == [40, 141, 142]
     mem = self.read_raw_mem(struct_foo2.getaddr(), 'c_long', 2)
     assert mem == [241, 242]
예제 #21
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_pointer_to_incomplete_struct(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
         ]
     descr = _StructDescr('foo')
     foo_ffitype = descr.ffitype
     foo_p = types.Pointer(descr.ffitype)
     assert foo_p.deref_pointer() is foo_ffitype
     descr.define_fields(fields)
     assert descr.ffitype is foo_ffitype
     assert foo_p.deref_pointer() is foo_ffitype
     assert types.Pointer(descr.ffitype) is foo_p
예제 #22
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 def test_pointer_to_incomplete_struct(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
     ]
     descr = _StructDescr('foo')
     foo_ffitype = descr.ffitype
     foo_p = types.Pointer(descr.ffitype)
     assert foo_p.deref_pointer() is foo_ffitype
     descr.define_fields(fields)
     assert descr.ffitype is foo_ffitype
     assert foo_p.deref_pointer() is foo_ffitype
     assert types.Pointer(descr.ffitype) is foo_p
예제 #23
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 def test_getfield_setfield(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('x', 42)
     struct.setfield('y', 43)
     assert struct.getfield('x') == 42
     assert struct.getfield('y') == 43
     mem = self.read_raw_mem(struct.getaddr(), 'c_long', 2)
     assert mem == [42, 43]
예제 #24
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 def test_getfield_setfield_longlong(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('slonglong', types.slonglong),
         Field('ulonglong', types.ulonglong),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('slonglong', 9223372036854775808)
     assert struct.getfield('slonglong') == -9223372036854775808
     struct.setfield('ulonglong', -1)
     assert struct.getfield('ulonglong') == 18446744073709551615
     mem = self.read_raw_mem(struct.getaddr(), 'c_longlong', 2)
     assert mem == [-9223372036854775808, -1]
예제 #25
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_getfield_setfield_longlong(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('slonglong', types.slonglong),
         Field('ulonglong', types.ulonglong),
         ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('slonglong', 9223372036854775808)
     assert struct.getfield('slonglong') == -9223372036854775808
     struct.setfield('ulonglong', -1)
     assert struct.getfield('ulonglong') == 18446744073709551615        
     mem = self.read_raw_mem(struct.getaddr(), 'c_longlong', 2)
     assert mem == [-9223372036854775808, -1]
예제 #26
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 def test_define_fields(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
     ]
     descr = _StructDescr('foo')
     assert descr.ffitype.name == 'struct foo'
     assert repr(descr.ffitype) == '<ffi type struct foo (incomplete)>'
     raises(ValueError, "descr.ffitype.sizeof()")
     raises(ValueError, "descr.allocate()")
     #
     descr.define_fields(fields)
     assert repr(descr.ffitype) == '<ffi type struct foo>'
     assert descr.ffitype.sizeof() == longsize * 2
     raises(ValueError, "descr.define_fields(fields)")
예제 #27
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_define_fields(self):
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.slong),
         Field('y', types.slong),
         ]
     descr = _StructDescr('foo')
     assert descr.ffitype.name == 'struct foo'
     assert repr(descr.ffitype) == '<ffi type struct foo (incomplete)>'
     raises(ValueError, "descr.ffitype.sizeof()")
     raises(ValueError, "descr.allocate()")
     #
     descr.define_fields(fields)
     assert repr(descr.ffitype) == '<ffi type struct foo>'
     assert descr.ffitype.sizeof() == longsize*2
     raises(ValueError, "descr.define_fields(fields)")
예제 #28
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 def test_getfield_setfield_singlefloat(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.float),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('x', 123.4)  # this is a value which DOES loose
     # precision in a single float
     assert 0 < abs(struct.getfield('x') - 123.4) < 0.0001
     #
     struct.setfield('x', 123.5)  # this is a value which does not loose
     # precision in a single float
     assert struct.getfield('x') == 123.5
     mem = self.read_raw_mem(struct.getaddr(), 'c_float', 1)
     assert mem == [123.5]
예제 #29
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_getfield_setfield_singlefloat(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('x', types.float),
         ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('x', 123.4) # this is a value which DOES loose
                                 # precision in a single float
     assert 0 < abs(struct.getfield('x') - 123.4) < 0.0001
     #
     struct.setfield('x', 123.5) # this is a value which does not loose
                                 # precision in a single float
     assert struct.getfield('x') == 123.5
     mem = self.read_raw_mem(struct.getaddr(), 'c_float', 1)
     assert mem == [123.5]
예제 #30
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 def test_byval_result(self):
     """
         DLLEXPORT struct Point make_point(long x, long y) {
             struct Point p;
             p.x = x;
             p.y = y;
             return p;
         }
     """
     from _rawffi.alt import CDLL, types, _StructDescr, Field
     Point = _StructDescr('Point', [
             Field('x', types.slong),
             Field('y', types.slong),
             ])
     libfoo = CDLL(self.libfoo_name)
     make_point = libfoo.getfunc('make_point', [types.slong, types.slong],
                                 Point.ffitype)
     #
     p = make_point(12, 34)
     assert p.getfield('x') == 12
     assert p.getfield('y') == 34
예제 #31
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 def test_byval_result(self):
     """
         DLLEXPORT struct Point make_point(long x, long y) {
             struct Point p;
             p.x = x;
             p.y = y;
             return p;
         }
     """
     from _rawffi.alt import CDLL, types, _StructDescr, Field
     Point = _StructDescr('Point', [
         Field('x', types.slong),
         Field('y', types.slong),
     ])
     libfoo = CDLL(self.libfoo_name)
     make_point = libfoo.getfunc('make_point', [types.slong, types.slong],
                                 Point.ffitype)
     #
     p = make_point(12, 34)
     assert p.getfield('x') == 12
     assert p.getfield('y') == 34
예제 #32
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 def test_getfield_setfield_signed_types(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('sbyte', types.sbyte),
         Field('sshort', types.sshort),
         Field('sint', types.sint),
         Field('slong', types.slong),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('sbyte', 128)
     assert struct.getfield('sbyte') == -128
     struct.setfield('sshort', 32768)
     assert struct.getfield('sshort') == -32768
     struct.setfield('sint', 43)
     assert struct.getfield('sint') == 43
     struct.setfield('slong', sys.maxint + 1)
     assert struct.getfield('slong') == -sys.maxint - 1
     struct.setfield('slong', sys.maxint * 3)
     assert struct.getfield('slong') == sys.maxint - 2
예제 #33
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파일: test_struct.py 프로젝트: Qointum/pypy
 def test_getfield_setfield_signed_types(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     longsize = types.slong.sizeof()
     fields = [
         Field('sbyte', types.sbyte),
         Field('sshort', types.sshort),
         Field('sint', types.sint),
         Field('slong', types.slong),
         ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('sbyte', 128)
     assert struct.getfield('sbyte') == -128
     struct.setfield('sshort', 32768)
     assert struct.getfield('sshort') == -32768
     struct.setfield('sint', 43)
     assert struct.getfield('sint') == 43
     struct.setfield('slong', sys.maxsize+1)
     assert struct.getfield('slong') == -sys.maxsize-1
     struct.setfield('slong', sys.maxsize*3)
     assert struct.getfield('slong') == sys.maxsize-2
예제 #34
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    def test_byval_argument(self):
        """
            struct Point {
                long x;
                long y;
            };

            DLLEXPORT long sum_point(struct Point p) {
                return p.x + p.y;
            }
        """
        from _rawffi.alt import CDLL, types, _StructDescr, Field
        Point = _StructDescr('Point', [
                Field('x', types.slong),
                Field('y', types.slong),
                ])
        libfoo = CDLL(self.libfoo_name)
        sum_point = libfoo.getfunc('sum_point', [Point.ffitype], types.slong)
        #
        p = Point.allocate()
        p.setfield('x', 30)
        p.setfield('y', 12)
        res = sum_point(p)
        assert res == 42
예제 #35
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    def test_byval_argument(self):
        """
            struct Point {
                long x;
                long y;
            };

            DLLEXPORT long sum_point(struct Point p) {
                return p.x + p.y;
            }
        """
        from _rawffi.alt import CDLL, types, _StructDescr, Field
        Point = _StructDescr('Point', [
            Field('x', types.slong),
            Field('y', types.slong),
        ])
        libfoo = CDLL(self.libfoo_name)
        sum_point = libfoo.getfunc('sum_point', [Point.ffitype], types.slong)
        #
        p = Point.allocate()
        p.setfield('x', 30)
        p.setfield('y', 12)
        res = sum_point(p)
        assert res == 42
예제 #36
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 def test_getfield_setfield_signed_types(self):
     import sys
     from _rawffi.alt import _StructDescr, Field, types
     maxlong = sys.maxint
     if sys.platform == 'win32':
         maxlong = 2147483647
     fields = [
         Field('sbyte', types.sbyte),
         Field('sshort', types.sshort),
         Field('sint', types.sint),
         Field('slong', types.slong),
     ]
     descr = _StructDescr('foo', fields)
     struct = descr.allocate()
     struct.setfield('sbyte', 128)
     assert struct.getfield('sbyte') == -128
     struct.setfield('sshort', 32768)
     assert struct.getfield('sshort') == -32768
     struct.setfield('sint', 43)
     assert struct.getfield('sint') == 43
     struct.setfield('slong', maxlong + 1)
     assert struct.getfield('slong') == -maxlong - 1
     struct.setfield('slong', maxlong * 3)
     assert struct.getfield('slong') == maxlong - 2