1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
import struct
import abc
import re
from typing import Optional, Tuple
def pldstr(self) -> str:
attrs = []
for field in self.__class__.__annotations__:
if hasattr(self, field):
attr = getattr(self, field)
attrs.append(f'{field}={attr}')
if attrs:
attrs_s = ' '
attrs_s += ', '.join(attrs)
else:
attrs_s = ''
return f'<%s{attrs_s}>' % (self.__class__.__name__,)
class MqttPayload(abc.ABC):
FORMAT = ''
PACKER = {}
UNPACKER = {}
def __init__(self, **kwargs):
for field in self.__class__.__annotations__:
setattr(self, field, kwargs[field])
def pack(self):
args = []
bf_number = -1
bf_arg = 0
bf_progress = 0
for field, field_type in self.__class__.__annotations__.items():
bfp = _bit_field_params(field_type)
if bfp:
n, s, b = bfp
if n != bf_number:
if bf_number != -1:
args.append(bf_arg)
bf_number = n
bf_progress = 0
bf_arg = 0
bf_arg |= (getattr(self, field) & (2 ** b - 1)) << bf_progress
bf_progress += b
else:
if bf_number != -1:
args.append(bf_arg)
bf_number = -1
bf_progress = 0
bf_arg = 0
args.append(self._pack_field(field))
if bf_number != -1:
args.append(bf_arg)
return struct.pack(self.FORMAT, *args)
@classmethod
def unpack(cls, buf: bytes):
data = struct.unpack(cls.FORMAT, buf)
kwargs = {}
i = 0
bf_number = -1
bf_progress = 0
for field, field_type in cls.__annotations__.items():
bfp = _bit_field_params(field_type)
if bfp:
n, s, b = bfp
if n != bf_number:
bf_number = n
bf_progress = 0
kwargs[field] = (data[i] >> bf_progress) & (2 ** b - 1)
bf_progress += b
continue # don't increment i
if bf_number != -1:
bf_number = -1
i += 1
if issubclass(field_type, MqttPayloadCustomField):
kwargs[field] = field_type.unpack(data[i])
else:
kwargs[field] = cls._unpack_field(field, data[i])
i += 1
return cls(**kwargs)
def _pack_field(self, name):
val = getattr(self, name)
if self.PACKER and name in self.PACKER:
return self.PACKER[name](val)
else:
return val
@classmethod
def _unpack_field(cls, name, val):
if isinstance(val, MqttPayloadCustomField):
return
if cls.UNPACKER and name in cls.UNPACKER:
return cls.UNPACKER[name](val)
else:
return val
def __str__(self):
return pldstr(self)
class MqttPayloadCustomField(abc.ABC):
def __init__(self, **kwargs):
for field in self.__class__.__annotations__:
setattr(self, field, kwargs[field])
@abc.abstractmethod
def __index__(self):
pass
@classmethod
@abc.abstractmethod
def unpack(cls, *args, **kwargs):
pass
def __str__(self):
return pldstr(self)
def bit_field(seq_no: int, total_bits: int, bits: int):
return type(f'MQTTPayloadBitField_{seq_no}_{total_bits}_{bits}', (object,), {
'seq_no': seq_no,
'total_bits': total_bits,
'bits': bits
})
def _bit_field_params(cl) -> Optional[Tuple[int, ...]]:
match = re.match(r'MQTTPayloadBitField_(\d+)_(\d+)_(\d)$', cl.__name__)
if match is not None:
return tuple([int(match.group(i)) for i in range(1, 4)])
return None
|
