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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
from __future__ import annotations
import typing
import inspect
import dataclasses
import zigpy.types as zigpy_t
import zigpy_znp.types as t
class ListSubclass(list):
# So we can call `setattr()` on it
pass
@dataclasses.dataclass(frozen=True)
class CStructField:
name: str
type: type
def __post_init__(self) -> None:
# Throw an error early
self.get_size_and_alignment()
def get_size_and_alignment(self, align=False) -> tuple[int, int]:
if issubclass(self.type, zigpy_t.FixedIntType):
assert self.type._size is not None
return self.type._size, (self.type._size if align else 1)
elif issubclass(self.type, zigpy_t.EUI64):
return 8, 1
elif issubclass(self.type, zigpy_t.KeyData):
return 16, 1
elif issubclass(self.type, CStruct):
return self.type.get_size(align=align), self.type.get_alignment(align=align)
elif issubclass(self.type, t.AddrModeAddress):
return 1 + 8, 1
else:
raise TypeError(f"Cannot get size of unknown type: {self.type!r}")
class CStruct:
_padding_byte = b"\xFF"
def __init_subclass__(cls):
super().__init_subclass__()
fields = ListSubclass()
for name, annotation in typing.get_type_hints(cls).items():
try:
field = CStructField(name=name, type=annotation)
except Exception as e:
raise TypeError(f"Invalid field {name}={annotation!r}") from e
fields.append(field)
setattr(fields, field.name, field)
cls.fields = fields
def __new__(cls, *args, **kwargs) -> CStruct:
# Like a copy constructor
if len(args) == 1 and isinstance(args[0], cls):
if kwargs:
raise ValueError(f"Cannot use copy constructor with kwargs: {kwargs!r}")
kwargs = args[0].as_dict()
args = ()
# Pretend our signature is `__new__(cls, p1: t1, p2: t2, ...)`
signature = inspect.Signature(
parameters=[
inspect.Parameter(
name=f.name,
kind=inspect.Parameter.POSITIONAL_OR_KEYWORD,
default=None,
annotation=f.type,
)
for f in cls.fields
]
)
bound = signature.bind(*args, **kwargs)
bound.apply_defaults()
instance = super().__new__(cls)
# Set and convert the attributes to their respective types
for name, value in bound.arguments.items():
field = getattr(cls.fields, name)
if value is not None:
try:
value = field.type(value)
except Exception as e:
raise ValueError(
f"Failed to convert {name}={value!r} from type"
f" {type(value)} to {field.type}"
) from e
setattr(instance, name, value)
return instance
def as_dict(self) -> dict[str, typing.Any]:
return {f.name: getattr(self, f.name) for f in self.fields}
@classmethod
def get_padded_fields(
cls, *, align=False
) -> typing.Iterable[tuple[int, int, CStructField]]:
offset = 0
for field in cls.fields:
size, alignment = field.get_size_and_alignment(align=align)
padding = (-offset) % alignment
offset += padding + size
yield padding, size, field
@classmethod
def get_alignment(cls, *, align=False) -> int:
alignments = []
for field in cls.fields:
size, alignment = field.get_size_and_alignment(align=align)
alignments.append(alignment)
return max(alignments)
@classmethod
def get_size(cls, *, align=False) -> int:
total_size = 0
for padding, size, _field in cls.get_padded_fields(align=align):
total_size += padding + size
final_padding = (-total_size) % cls.get_alignment(align=align)
return total_size + final_padding
def serialize(self, *, align=False) -> bytes:
result = b""
for padding, _, field in self.get_padded_fields(align=align):
value = getattr(self, field.name)
if value is None:
raise ValueError(f"Field {field} cannot be empty")
try:
value = field.type(value)
except Exception as e:
raise ValueError(
f"Failed to convert {field.name}={value!r} from type"
f" {type(value)} to {field.type}"
) from e
result += self._padding_byte * padding
if isinstance(value, CStruct):
result += value.serialize(align=align)
else:
result += value.serialize()
# Pad the result to our final length
return result.ljust(self.get_size(align=align), self._padding_byte)
@classmethod
def deserialize(cls, data: bytes, *, align=False) -> tuple[CStruct, bytes]:
instance = cls()
orig_length = len(data)
expected_size = cls.get_size(align=align)
if orig_length < expected_size:
raise ValueError(
f"Data is too short, must be at least {expected_size} bytes: {data!r}"
)
for padding, _, field in cls.get_padded_fields(align=align):
data = data[padding:]
if issubclass(field.type, CStruct):
value, data = field.type.deserialize(data, align=align)
else:
value, data = field.type.deserialize(data)
setattr(instance, field.name, value)
# Strip off the final padding
data = data[expected_size - (orig_length - len(data)) :]
return instance, data
def replace(self, **kwargs) -> CStruct:
d = self.as_dict().copy()
d.update(kwargs)
return type(self)(**d)
def __eq__(self, other: object) -> bool:
if not isinstance(self, type(other)) and not isinstance(other, type(self)):
return NotImplemented
return self.as_dict() == other.as_dict()
def __repr__(self) -> str:
kwargs = ", ".join([f"{k}={v!r}" for k, v in self.as_dict().items()])
return f"{type(self).__name__}({kwargs})"
|
