import binascii
import ctypes
import math
import struct
import sys
import unittest
from ctypes import (Structure, Union, LittleEndianUnion, BigEndianUnion,
BigEndianStructure, LittleEndianStructure,
POINTER, sizeof, cast,
c_byte, c_ubyte, c_char, c_wchar, c_void_p,
c_short, c_ushort, c_int, c_uint,
c_long, c_ulong, c_longlong, c_ulonglong,
c_uint32, c_float, c_double)
def bin(s):
return binascii.hexlify(memoryview(s)).decode().upper()
# Each *simple* type that supports different byte orders has an
# __ctype_be__ attribute that specifies the same type in BIG ENDIAN
# byte order, and a __ctype_le__ attribute that is the same type in
# LITTLE ENDIAN byte order.
#
# For Structures and Unions, these types are created on demand.
class Test(unittest.TestCase):
def test_slots(self):
class BigPoint(BigEndianStructure):
__slots__ = ()
_fields_ = [("x", c_int), ("y", c_int)]
class LowPoint(LittleEndianStructure):
__slots__ = ()
_fields_ = [("x", c_int), ("y", c_int)]
big = BigPoint()
little = LowPoint()
big.x = 4
big.y = 2
little.x = 2
little.y = 4
with self.assertRaises(AttributeError):
big.z = 42
with self.assertRaises(AttributeError):
little.z = 24
def test_endian_short(self):
if sys.byteorder == "little":
self.assertIs(c_short.__ctype_le__, c_short)
self.assertIs(c_short.__ctype_be__.__ctype_le__, c_short)
else:
self.assertIs(c_short.__ctype_be__, c_short)
self.assertIs(c_short.__ctype_le__.__ctype_be__, c_short)
s = c_short.__ctype_be__(0x1234)
self.assertEqual(bin(struct.pack(">h", 0x1234)), "1234")
self.assertEqual(bin(s), "1234")
self.assertEqual(s.value, 0x1234)
s = c_short.__ctype_le__(0x1234)
self.assertEqual(bin(struct.pack("<h", 0x1234)), "3412")
self.assertEqual(bin(s), "3412")
self.assertEqual(s.value, 0x1234)
s = c_ushort.__ctype_be__(0x1234)
self.assertEqual(bin(struct.pack(">h", 0x1234)), "1234")
self.assertEqual(bin(s), "1234")
self.assertEqual(s.value, 0x1234)
s = c_ushort.__ctype_le__(0x1234)
self.assertEqual(bin(struct.pack("<h", 0x1234)), "3412")
self.assertEqual(bin(s), "3412")
self.assertEqual(s.value, 0x1234)
def test_endian_int(self):
if sys.byteorder == "little":
self.assertIs(c_int.__ctype_le__, c_int)
self.assertIs(c_int.__ctype_be__.__ctype_le__, c_int)
else:
self.assertIs(c_int.__ctype_be__, c_int)
self.assertIs(c_int.__ctype_le__.__ctype_be__, c_int)
s = c_int.__ctype_be__(0x12345678)
self.assertEqual(bin(struct.pack(">i", 0x12345678)), "12345678")
self.assertEqual(bin(s), "12345678")
self.assertEqual(s.value, 0x12345678)
s = c_int.__ctype_le__(0x12345678)
self.assertEqual(bin(struct.pack("<i", 0x12345678)), "78563412")
self.assertEqual(bin(s), "78563412")
self.assertEqual(s.value, 0x12345678)
s = c_uint.__ctype_be__(0x12345678)
self.assertEqual(bin(struct.pack(">I", 0x12345678)), "12345678")
self.assertEqual(bin(s), "12345678")
self.assertEqual(s.value, 0x12345678)
s = c_uint.__ctype_le__(0x12345678)
self.assertEqual(bin(struct.pack("<I", 0x12345678)), "78563412")
self.assertEqual(bin(s), "78563412")
self.assertEqual(s.value, 0x12345678)
def test_endian_longlong(self):
if sys.byteorder == "little":
self.assertIs(c_longlong.__ctype_le__, c_longlong)
self.assertIs(c_longlong.__ctype_be__.__ctype_le__, c_longlong)
else:
self.assertIs(c_longlong.__ctype_be__, c_longlong)
self.assertIs(c_longlong.__ctype_le__.__ctype_be__, c_longlong)
s = c_longlong.__ctype_be__(0x1234567890ABCDEF)
self.assertEqual(bin(struct.pack(">q", 0x1234567890ABCDEF)), "1234567890ABCDEF")
self.assertEqual(bin(s), "1234567890ABCDEF")
self.assertEqual(s.value, 0x1234567890ABCDEF)
s = c_longlong.__ctype_le__(0x1234567890ABCDEF)
self.assertEqual(bin(struct.pack("<q", 0x1234567890ABCDEF)), "EFCDAB9078563412")
self.assertEqual(bin(s), "EFCDAB9078563412")
self.assertEqual(s.value, 0x1234567890ABCDEF)
s = c_ulonglong.__ctype_be__(0x1234567890ABCDEF)
self.assertEqual(bin(struct.pack(">Q", 0x1234567890ABCDEF)), "1234567890ABCDEF")
self.assertEqual(bin(s), "1234567890ABCDEF")
self.assertEqual(s.value, 0x1234567890ABCDEF)
s = c_ulonglong.__ctype_le__(0x1234567890ABCDEF)
self.assertEqual(bin(struct.pack("<Q", 0x1234567890ABCDEF)), "EFCDAB9078563412")
self.assertEqual(bin(s), "EFCDAB9078563412")
self.assertEqual(s.value, 0x1234567890ABCDEF)
def test_endian_float(self):
if sys.byteorder == "little":
self.assertIs(c_float.__ctype_le__, c_float)
self.assertIs(c_float.__ctype_be__.__ctype_le__, c_float)
else:
self.assertIs(c_float.__ctype_be__, c_float)
self.assertIs(c_float.__ctype_le__.__ctype_be__, c_float)
s = c_float(math.pi)
self.assertEqual(bin(struct.pack("f", math.pi)), bin(s))
# Hm, what's the precision of a float compared to a double?
self.assertAlmostEqual(s.value, math.pi, places=6)
s = c_float.__ctype_le__(math.pi)
self.assertAlmostEqual(s.value, math.pi, places=6)
self.assertEqual(bin(struct.pack("<f", math.pi)), bin(s))
s = c_float.__ctype_be__(math.pi)
self.assertAlmostEqual(s.value, math.pi, places=6)
self.assertEqual(bin(struct.pack(">f", math.pi)), bin(s))
def test_endian_double(self):
if sys.byteorder == "little":
self.assertIs(c_double.__ctype_le__, c_double)
self.assertIs(c_double.__ctype_be__.__ctype_le__, c_double)
else:
self.assertIs(c_double.__ctype_be__, c_double)
self.assertIs(c_double.__ctype_le__.__ctype_be__, c_double)
s = c_double(math.pi)
self.assertEqual(s.value, math.pi)
self.assertEqual(bin(struct.pack("d", math.pi)), bin(s))
s = c_double.__ctype_le__(math.pi)
self.assertEqual(s.value, math.pi)
self.assertEqual(bin(struct.pack("<d", math.pi)), bin(s))
s = c_double.__ctype_be__(math.pi)
self.assertEqual(s.value, math.pi)
self.assertEqual(bin(struct.pack(">d", math.pi)), bin(s))
def test_endian_other(self):
self.assertIs(c_byte.__ctype_le__, c_byte)
self.assertIs(c_byte.__ctype_be__, c_byte)
self.assertIs(c_ubyte.__ctype_le__, c_ubyte)
self.assertIs(c_ubyte.__ctype_be__, c_ubyte)
self.assertIs(c_char.__ctype_le__, c_char)
self.assertIs(c_char.__ctype_be__, c_char)
def test_struct_fields_unsupported_byte_order(self):
fields = [
("a", c_ubyte),
("b", c_byte),
("c", c_short),
("d", c_ushort),
("e", c_int),
("f", c_uint),
("g", c_long),
("h", c_ulong),
("i", c_longlong),
("k", c_ulonglong),
("l", c_float),
("m", c_double),
("n", c_char),
("b1", c_byte, 3),
("b2", c_byte, 3),
("b3", c_byte, 2),
("a", c_int * 3 * 3 * 3)
]
# these fields do not support different byte order:
for typ in c_wchar, c_void_p, POINTER(c_int):
with self.assertRaises(TypeError):
class T(BigEndianStructure if sys.byteorder == "little" else LittleEndianStructure):
_fields_ = fields + [("x", typ)]
def test_struct_struct(self):
# nested structures with different byteorders
# create nested structures with given byteorders and set memory to data
for nested, data in (
(BigEndianStructure, b'\0\0\0\1\0\0\0\2'),
(LittleEndianStructure, b'\1\0\0\0\2\0\0\0'),
):
for parent in (
BigEndianStructure,
LittleEndianStructure,
Structure,
):
class NestedStructure(nested):
_fields_ = [("x", c_uint32),
("y", c_uint32)]
class TestStructure(parent):
_fields_ = [("point", NestedStructure)]
self.assertEqual(len(data), sizeof(TestStructure))
ptr = POINTER(TestStructure)
s = cast(data, ptr)[0]
del ctypes._pointer_type_cache[TestStructure]
self.assertEqual(s.point.x, 1)
self.assertEqual(s.point.y, 2)
def test_struct_field_alignment(self):
# standard packing in struct uses no alignment.
# So, we have to align using pad bytes.
#
# Unaligned accesses will crash Python (on those platforms that
# don't allow it, like sparc solaris).
if sys.byteorder == "little":
base = BigEndianStructure
fmt = ">bxhid"
else:
base = LittleEndianStructure
fmt = "<bxhid"
class S(base):
_fields_ = [("b", c_byte),
("h", c_short),
("i", c_int),
("d", c_double)]
s1 = S(0x12, 0x1234, 0x12345678, 3.14)
s2 = struct.pack(fmt, 0x12, 0x1234, 0x12345678, 3.14)
self.assertEqual(bin(s1), bin(s2))
def test_unaligned_nonnative_struct_fields(self):
if sys.byteorder == "little":
base = BigEndianStructure
fmt = ">b h xi xd"
else:
base = LittleEndianStructure
fmt = "<b h xi xd"
class S(base):
_pack_ = 1
_fields_ = [("b", c_byte),
("h", c_short),
("_1", c_byte),
("i", c_int),
("_2", c_byte),
("d", c_double)]
s1 = S()
s1.b = 0x12
s1.h = 0x1234
s1.i = 0x12345678
s1.d = 3.14
s2 = struct.pack(fmt, 0x12, 0x1234, 0x12345678, 3.14)
self.assertEqual(bin(s1), bin(s2))
def test_unaligned_native_struct_fields(self):
if sys.byteorder == "little":
fmt = "<b h xi xd"
else:
base = LittleEndianStructure
fmt = ">b h xi xd"
class S(Structure):
_pack_ = 1
_fields_ = [("b", c_byte),
("h", c_short),
("_1", c_byte),
("i", c_int),
("_2", c_byte),
("d", c_double)]
s1 = S()
s1.b = 0x12
s1.h = 0x1234
s1.i = 0x12345678
s1.d = 3.14
s2 = struct.pack(fmt, 0x12, 0x1234, 0x12345678, 3.14)
self.assertEqual(bin(s1), bin(s2))
def test_union_fields_unsupported_byte_order(self):
fields = [
("a", c_ubyte),
("b", c_byte),
("c", c_short),
("d", c_ushort),
("e", c_int),
("f", c_uint),
("g", c_long),
("h", c_ulong),
("i", c_longlong),
("k", c_ulonglong),
("l", c_float),
("m", c_double),
("n", c_char),
("b1", c_byte, 3),
("b2", c_byte, 3),
("b3", c_byte, 2),
("a", c_int * 3 * 3 * 3)
]
# these fields do not support different byte order:
for typ in c_wchar, c_void_p, POINTER(c_int):
with self.assertRaises(TypeError):
class T(BigEndianUnion if sys.byteorder == "little" else LittleEndianUnion):
_fields_ = fields + [("x", typ)]
def test_union_struct(self):
# nested structures in unions with different byteorders
# create nested structures in unions with given byteorders and set memory to data
for nested, data in (
(BigEndianStructure, b'\0\0\0\1\0\0\0\2'),
(LittleEndianStructure, b'\1\0\0\0\2\0\0\0'),
):
for parent in (
BigEndianUnion,
LittleEndianUnion,
Union,
):
class NestedStructure(nested):
_fields_ = [("x", c_uint32),
("y", c_uint32)]
class TestUnion(parent):
_fields_ = [("point", NestedStructure)]
self.assertEqual(len(data), sizeof(TestUnion))
ptr = POINTER(TestUnion)
s = cast(data, ptr)[0]
del ctypes._pointer_type_cache[TestUnion]
self.assertEqual(s.point.x, 1)
self.assertEqual(s.point.y, 2)
def test_build_struct_union_opposite_system_byteorder(self):
# gh-105102
if sys.byteorder == "little":
_Structure = BigEndianStructure
_Union = BigEndianUnion
else:
_Structure = LittleEndianStructure
_Union = LittleEndianUnion
class S1(_Structure):
_fields_ = [("a", c_byte), ("b", c_byte)]
class U1(_Union):
_fields_ = [("s1", S1), ("ab", c_short)]
class S2(_Structure):
_fields_ = [("u1", U1), ("c", c_byte)]
if __name__ == "__main__":
unittest.main()
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