An extension to ctypes.
- provide an easy way to define complex binary structures.
- provide a wrapper to make an object immutable.
from ctypes import *
from ctypes_ext import *
import pprint
# declare the C struct
S = struct[
('a', c_uint16),
('', c_uint16), # padding
('d', struct.anon[ # anonymous struct
('d0', c_uint8, 1),
('d1', c_uint8, 2)
]),
('e', 2 * struct[ # array of struct
('e0', c_uint8, 1),
('e1', c_uint8, 2)
]),
('f', 2 * c_uint32),
('c', union.anon[ # anonymous union
('cv', c_uint8),
('', union.anon[
('cs', struct[
('c0', c_uint8, 4),
cenum('c0',{0:'Zero', 1: 'One', 2: 'Two', 3: 'Three'}), # annotate a field with enum
('c1', c_uint8, 4)
]),
('cs1', struct[
('c0', c_uint8, 4),
('c1', c_uint8, 4)
]),
]),
]),
cinit('a', 1),
cinit('c.cs.c0', 2),
cinit('d1', 3),
]
# create object with the type S
s=S()
print("---------------test1--------------------")
print(s)
print("---------------test2--------------------")
s.f[0]=123
s.f[1]=456
s.e[0].e0=1
s.e[0].e1=2
s.e[1].e1=3
print(str(s))
print("---------------test3--------------------")
d1=s.to_dict()
pprint.pprint(d1)
print("-----------------------------------")
s2=S()
s2.load_dict(d1, invalid_field=0xabcd)
print(s2)
assert(str(s)==str(s2))
print("-----------------------------------")
d1['d']['invalid_field'] = 0x12345
s3=S.load_dict(d1)
print(s3)
assert(str(s) == str(s3))
print("______________________________________")
# check accessibility of fields
s.a
s.c; s.cv; s.cs
s.cs.c0; s.cs.c1
s.d
s.d0; s.d1
s.e[0]
s.e[0].e0; s.e[0].e1
s.f[0]---------------test1--------------------
struct{
a <c_ushort> = 0x1
<c_ushort> = 0x0
d <struct.anon> = struct.anon{
d0 <c_ubyte:1> = 0x0
d1 <c_ubyte:2> = 0x3
}
e <struct_Array_2> = [
0=> struct{
e0 <c_ubyte:1> = 0x0
e1 <c_ubyte:2> = 0x0
}
1=> struct{
e0 <c_ubyte:1> = 0x0
e1 <c_ubyte:2> = 0x0
}
]
f <c_ulong_Array_2> = [0x0, 0x0]
c <union.anon> = union.anon{
cv <c_ubyte> = 0x2
<union.anon> = union.anon{
cs <struct> = struct{
c0 <c_ubyte:4> = 0x2 <Two>
c1 <c_ubyte:4> = 0x0
}
cs1 <struct> = struct{
c0 <c_ubyte:4> = 0x2
c1 <c_ubyte:4> = 0x0
}
}
}
}
---------------test2--------------------
struct{
a <c_ushort> = 0x1
<c_ushort> = 0x0
d <struct.anon> = struct.anon{
d0 <c_ubyte:1> = 0x0
d1 <c_ubyte:2> = 0x3
}
e <struct_Array_2> = [
0=> struct{
e0 <c_ubyte:1> = 0x1
e1 <c_ubyte:2> = 0x2
}
1=> struct{
e0 <c_ubyte:1> = 0x0
e1 <c_ubyte:2> = 0x3
}
]
f <c_ulong_Array_2> = [0x7b, 0x1c8]
c <union.anon> = union.anon{
cv <c_ubyte> = 0x2
<union.anon> = union.anon{
cs <struct> = struct{
c0 <c_ubyte:4> = 0x2 <Two>
c1 <c_ubyte:4> = 0x0
}
cs1 <struct> = struct{
c0 <c_ubyte:4> = 0x2
c1 <c_ubyte:4> = 0x0
}
}
}
}
---------------test3--------------------
{'a': 1,
'c': {'cv':2, 'cs':{'c0':2, 'c1':0}, 'cs1':{'c0':2, 'c1':0}},
'd': {'d0':0, 'd1':3},
'e': [{'e0':1, 'e1':2}, {'e0':0, 'e1':3}],
'f': [123, 456]}
-----------------------------------
WARNING: when load_dict to ctypes object, <cobj@2760473570832>.invalid_field not exist and setting this field to 43981(0xabcd) is ignored.
File "./ctypes_ext/_impl.py", line 376, in <module>
s2.load_dict(d1, invalid_field=0xabcd)
struct{
a <c_ushort> = 0x1
<c_ushort> = 0x0
d <struct.anon> = struct.anon{
d0 <c_ubyte:1> = 0x0
d1 <c_ubyte:2> = 0x3
}
e <struct_Array_2> = [
0=> struct{
e0 <c_ubyte:1> = 0x1
e1 <c_ubyte:2> = 0x2
}
1=> struct{
e0 <c_ubyte:1> = 0x0
e1 <c_ubyte:2> = 0x3
}
]
f <c_ulong_Array_2> = [0x7b, 0x1c8]
c <union.anon> = union.anon{
cv <c_ubyte> = 0x2
<union.anon> = union.anon{
cs <struct> = struct{
c0 <c_ubyte:4> = 0x2 <Two>
c1 <c_ubyte:4> = 0x0
}
cs1 <struct> = struct{
c0 <c_ubyte:4> = 0x2
c1 <c_ubyte:4> = 0x0
}
}
}
}
-----------------------------------
WARNING: when load_dict to ctypes object, <cobj@2760473570452>.invalid_field not exist and setting this field to 74565(0x12345) is ignored.
File "./ctypes_ext/_impl.py", line 381, in <module>
s3=S.load_dict(d1)
struct{
a <c_ushort> = 0x1
<c_ushort> = 0x0
d <struct.anon> = struct.anon{
d0 <c_ubyte:1> = 0x0
d1 <c_ubyte:2> = 0x3
}
e <struct_Array_2> = [
0=> struct{
e0 <c_ubyte:1> = 0x1
e1 <c_ubyte:2> = 0x2
}
1=> struct{
e0 <c_ubyte:1> = 0x0
e1 <c_ubyte:2> = 0x3
}
]
f <c_ulong_Array_2> = [0x7b, 0x1c8]
c <union.anon> = union.anon{
cv <c_ubyte> = 0x2
<union.anon> = union.anon{
cs <struct> = struct{
c0 <c_ubyte:4> = 0x2 <Two>
c1 <c_ubyte:4> = 0x0
}
cs1 <struct> = struct{
c0 <c_ubyte:4> = 0x2
c1 <c_ubyte:4> = 0x0
}
}
}
}
______________________________________
{
'a': 0x1,
'd': {
'd0': 0x0,
'd1': 0x3,
},
'e': [
{
'e0': 0x1,
'e1': 0x2,
},
{
'e0': 0x0,
'e1': 0x3,
}
],
'f': [0x7b, 0x1c8],
'c': {
'cv': 0x2,
'cs': {
'c0': 0x2,
'c1': 0x0,
},
'cs1': {
'c0': 0x2,
'c1': 0x0,
},
},
}
-----------------------------------