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[3.6] bpo-10746: Fix ctypes PEP 3118 type codes for c_long, c_bool, c_int (GH-31) (#3241)

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Ctypes currently produces wrong pep3118 type codes for several types.
E.g. memoryview(ctypes.c_long()).format gives "<l" on 64-bit platforms,
but it should be "<q" instead for sizeof(c_long) == 8

The problem is that the '<>' endian specification in the struct syntax
also turns on the "standard size" mode, which makes type characters have
a platform-independent meaning, which does not match with the codes used
internally in ctypes.  The struct module format syntax also does not
allow specifying native-size non-native-endian items.

This commit adds a converter function that maps the internal ctypes
codes to appropriate struct module standard-size codes in the pep3118
format strings. The tests are modified to check for this.
(cherry picked from commit 07f1658aa0)
This commit is contained in:
Pauli Virtanen 2017-08-30 11:40:05 +02:00 • committed by Antoine Pitrou
parent 87c50245b1
commit 2d1653aa43
3 changed files with 123 additions and 30 deletions
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83
Lib/ctypes/test/test_pep3118.py
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@ -112,6 +112,34 @@ Complete._fields_ = [("a", c_long)]
# This table contains format strings as they look on little endian
# machines. The test replaces '<' with '>' on big endian machines.
#
# Platform-specific type codes
s_bool = {1: '?', 2: 'H', 4: 'L', 8: 'Q'}[sizeof(c_bool)]
s_short = {2: 'h', 4: 'l', 8: 'q'}[sizeof(c_short)]
s_ushort = {2: 'H', 4: 'L', 8: 'Q'}[sizeof(c_ushort)]
s_int = {2: 'h', 4: 'i', 8: 'q'}[sizeof(c_int)]
s_uint = {2: 'H', 4: 'I', 8: 'Q'}[sizeof(c_uint)]
s_long = {4: 'l', 8: 'q'}[sizeof(c_long)]
s_ulong = {4: 'L', 8: 'Q'}[sizeof(c_ulong)]
s_longlong = "q"
s_ulonglong = "Q"
s_float = "f"
s_double = "d"
s_longdouble = "g"
# Alias definitions in ctypes/__init__.py
if c_int is c_long:
s_int = s_long
if c_uint is c_ulong:
s_uint = s_ulong
if c_longlong is c_long:
s_longlong = s_long
if c_ulonglong is c_ulong:
s_ulonglong = s_ulong
if c_longdouble is c_double:
s_longdouble = s_double
native_types = [
# type format shape calc itemsize
@ -120,52 +148,51 @@ native_types = [
(c_char, "<c", (), c_char),
(c_byte, "<b", (), c_byte),
(c_ubyte, "<B", (), c_ubyte),
(c_short, "<h", (), c_short),
(c_ushort, "<H", (), c_ushort),
(c_short, "<" + s_short, (), c_short),
(c_ushort, "<" + s_ushort, (), c_ushort),
# c_int and c_uint may be aliases to c_long
#(c_int, "<i", (), c_int),
#(c_uint, "<I", (), c_uint),
(c_int, "<" + s_int, (), c_int),
(c_uint, "<" + s_uint, (), c_uint),
(c_long, "<l", (), c_long),
(c_ulong, "<L", (), c_ulong),
(c_long, "<" + s_long, (), c_long),
(c_ulong, "<" + s_ulong, (), c_ulong),
# c_longlong and c_ulonglong are aliases on 64-bit platforms
#(c_longlong, "<q", None, c_longlong),
#(c_ulonglong, "<Q", None, c_ulonglong),
(c_longlong, "<" + s_longlong, (), c_longlong),
(c_ulonglong, "<" + s_ulonglong, (), c_ulonglong),
(c_float, "<f", (), c_float),
(c_double, "<d", (), c_double),
# c_longdouble may be an alias to c_double
(c_bool, "<?", (), c_bool),
(c_longdouble, "<" + s_longdouble, (), c_longdouble),
(c_bool, "<" + s_bool, (), c_bool),
(py_object, "<O", (), py_object),
## pointers
(POINTER(c_byte), "&<b", (), POINTER(c_byte)),
(POINTER(POINTER(c_long)), "&&<l", (), POINTER(POINTER(c_long))),
(POINTER(POINTER(c_long)), "&&<" + s_long, (), POINTER(POINTER(c_long))),
## arrays and pointers
(c_double * 4, "<d", (4,), c_double),
(c_float * 4 * 3 * 2, "<f", (2,3,4), c_float),
(POINTER(c_short) * 2, "&<h", (2,), POINTER(c_short)),
(POINTER(c_short) * 2 * 3, "&<h", (3,2,), POINTER(c_short)),
(POINTER(c_short * 2), "&(2)<h", (), POINTER(c_short)),
(POINTER(c_short) * 2, "&<" + s_short, (2,), POINTER(c_short)),
(POINTER(c_short) * 2 * 3, "&<" + s_short, (3,2,), POINTER(c_short)),
(POINTER(c_short * 2), "&(2)<" + s_short, (), POINTER(c_short)),
## structures and unions
(Point, "T{<l:x:<l:y:}", (), Point),
(Point, "T{<l:x:<l:y:}".replace('l', s_long), (), Point),
# packed structures do not implement the pep
(PackedPoint, "B", (), PackedPoint),
(Point2, "T{<l:x:<l:y:}", (), Point2),
(EmptyStruct, "T{}", (), EmptyStruct),
(PackedPoint, "B", (), PackedPoint),
(Point2, "T{<l:x:<l:y:}".replace('l', s_long), (), Point2),
(EmptyStruct, "T{}", (), EmptyStruct),
# the pep does't support unions
(aUnion, "B", (), aUnion),
(aUnion, "B", (), aUnion),
# structure with sub-arrays
(StructWithArrays, "T{(2,3)<l:x:(4)T{<l:x:<l:y:}:y:}", (), StructWithArrays),
(StructWithArrays * 3, "T{(2,3)<l:x:(4)T{<l:x:<l:y:}:y:}", (3,), StructWithArrays),
(StructWithArrays, "T{(2,3)<l:x:(4)T{<l:x:<l:y:}:y:}".replace('l', s_long), (), StructWithArrays),
(StructWithArrays * 3, "T{(2,3)<l:x:(4)T{<l:x:<l:y:}:y:}".replace('l', s_long), (3,), StructWithArrays),
## pointer to incomplete structure
(Incomplete, "B", (), Incomplete),
@ -173,7 +200,7 @@ native_types = [
# 'Complete' is a structure that starts incomplete, but is completed after the
# pointer type to it has been created.
(Complete, "T{<l:a:}", (), Complete),
(Complete, "T{<l:a:}".replace('l', s_long), (), Complete),
# Unfortunately the pointer format string is not fixed...
(POINTER(Complete), "&B", (), POINTER(Complete)),
@ -196,10 +223,10 @@ class LEPoint(LittleEndianStructure):
# and little endian machines.
#
endian_types = [
(BEPoint, "T{>l:x:>l:y:}", (), BEPoint),
(LEPoint, "T{<l:x:<l:y:}", (), LEPoint),
(POINTER(BEPoint), "&T{>l:x:>l:y:}", (), POINTER(BEPoint)),
(POINTER(LEPoint), "&T{<l:x:<l:y:}", (), POINTER(LEPoint)),
(BEPoint, "T{>l:x:>l:y:}".replace('l', s_long), (), BEPoint),
(LEPoint, "T{<l:x:<l:y:}".replace('l', s_long), (), LEPoint),
(POINTER(BEPoint), "&T{>l:x:>l:y:}".replace('l', s_long), (), POINTER(BEPoint)),
(POINTER(LEPoint), "&T{<l:x:<l:y:}".replace('l', s_long), (), POINTER(LEPoint)),
]
if __name__ == "__main__":