def test__StructDescr(self):
from _ffi 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'
def test_alignment(self):
from _ffi 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
def test_missing_field(self):
from _ffi 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)")
def test_getfield_setfield(self):
from _ffi 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]
def test_pointer_to_incomplete_struct(self):
from _ffi 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
def test_getfield_setfield_longlong(self):
import sys
from _ffi 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]
def test_define_fields(self):
from _ffi 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)")
def test_getfield_setfield_unsigned_types(self):
import sys
from _ffi 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.maxint * 2 + 1
struct.setfield('ulong', sys.maxint * 2 + 2)
assert struct.getfield('ulong') == 0
struct.setfield('char', 'a')
assert struct.getfield('char') == 'a'
struct.setfield('unichar', u'\u1234')
assert struct.getfield('unichar') == u'\u1234'
struct.setfield('ptr', -1)
assert struct.getfield('ptr') == sys.maxint * 2 + 1
def test_unknown_type(self):
if self.runappdirect:
skip('cannot use self.dummy_type with -A')
from _ffi 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)")
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 _ffi 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
def test_getfield_setfield_signed_types(self):
import sys
from _ffi 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
def test_getfield_setfield_float(self):
import sys
from _ffi 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]
def main():
from _ffi 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')
def test_byval_argument(self):
"""
struct Point {
long x;
long y;
};
DLLEXPORT long sum_point(struct Point p) {
return p.x + p.y;
}
"""
from _ffi 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
def test_nested_structure(self):
from _ffi 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]
def test_getfield_setfield_singlefloat(self):
import sys
from _ffi 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]
class Point(Structure):
_fields_ = [
Field('x', types.slong),
Field('y', types.slong),
]