6 class EarlyEnd(Exception):
9 class LateEnd(Exception):
12 def read((data, pos), length):
13 data2 = data[pos:pos + length]
14 if len(data2) != length:
16 return data2, (data, pos + length)
18 def size((data, pos)):
19 return len(data) - pos
25 rval = getattr(self, '_hash', None)
28 rval = self._hash = hash((type(self), frozenset(self.__dict__.items())))
34 def __eq__(self, other):
35 return type(other) is type(self) and other.__dict__ == self.__dict__
37 def __ne__(self, other):
38 return not (self == other)
40 def _unpack(self, data):
41 obj, (data2, pos) = self.read((data, 0))
51 f = self.write(None, obj)
61 def unpack(self, data):
62 obj = self._unpack(data)
65 if self._pack(obj) != data:
66 raise AssertionError()
71 data = self._pack(obj)
74 if self._unpack(data) != obj:
75 raise AssertionError((self._unpack(data), obj))
79 class VarIntType(Type):
81 data, file = read(file, 1)
86 desc, length, minimum = '<H', 2, 0xfd
88 desc, length, minimum = '<I', 4, 2**16
90 desc, length, minimum = '<Q', 8, 2**32
92 raise AssertionError()
93 data2, file = read(file, length)
94 res, = struct.unpack(desc, data2)
96 raise AssertionError('VarInt not canonically packed')
99 def write(self, file, item):
101 return file, struct.pack('<B', item)
103 return file, struct.pack('<BH', 0xfd, item)
104 elif item <= 0xffffffff:
105 return file, struct.pack('<BI', 0xfe, item)
106 elif item <= 0xffffffffffffffff:
107 return file, struct.pack('<BQ', 0xff, item)
109 raise ValueError('int too large for varint')
111 class VarStrType(Type):
112 _inner_size = VarIntType()
114 def read(self, file):
115 length, file = self._inner_size.read(file)
116 return read(file, length)
118 def write(self, file, item):
119 return self._inner_size.write(file, len(item)), item
121 class EnumType(Type):
122 def __init__(self, inner, pack_to_unpack):
124 self.pack_to_unpack = pack_to_unpack
126 self.unpack_to_pack = {}
127 for k, v in pack_to_unpack.iteritems():
128 if v in self.unpack_to_pack:
129 raise ValueError('duplicate value in pack_to_unpack')
130 self.unpack_to_pack[v] = k
132 def read(self, file):
133 data, file = self.inner.read(file)
134 if data not in self.pack_to_unpack:
135 raise ValueError('enum data (%r) not in pack_to_unpack (%r)' % (data, self.pack_to_unpack))
136 return self.pack_to_unpack[data], file
138 def write(self, file, item):
139 if item not in self.unpack_to_pack:
140 raise ValueError('enum item (%r) not in unpack_to_pack (%r)' % (item, self.unpack_to_pack))
141 return self.inner.write(file, self.unpack_to_pack[item])
143 class ListType(Type):
144 _inner_size = VarIntType()
146 def __init__(self, type):
149 def read(self, file):
150 length, file = self._inner_size.read(file)
152 for i in xrange(length):
153 item, file = self.type.read(file)
157 def write(self, file, item):
158 file = self._inner_size.write(file, len(item))
160 file = self.type.write(file, subitem)
163 class StructType(Type):
164 __slots__ = 'desc length'.split(' ')
166 def __init__(self, desc):
168 self.length = struct.calcsize(self.desc)
170 def read(self, file):
171 data, file = read(file, self.length)
172 return struct.unpack(self.desc, data)[0], file
174 def write(self, file, item):
175 return file, struct.pack(self.desc, item)
178 __slots__ = 'bytes step format_str max'.split(' ')
180 def __new__(cls, bits, endianness='little'):
182 assert endianness in ['little', 'big']
183 if bits in [8, 16, 32, 64]:
184 return StructType(('<' if endianness == 'little' else '>') + {8: 'B', 16: 'H', 32: 'I', 64: 'Q'}[bits])
186 return Type.__new__(cls, bits, endianness)
188 def __init__(self, bits, endianness='little'):
190 assert endianness in ['little', 'big']
192 self.step = -1 if endianness == 'little' else 1
193 self.format_str = '%%0%ix' % (2*self.bytes)
196 def read(self, file, b2a_hex=binascii.b2a_hex):
199 data, file = read(file, self.bytes)
200 return int(b2a_hex(data[::self.step]), 16), file
202 def write(self, file, item, a2b_hex=binascii.a2b_hex):
205 if not 0 <= item < self.max:
206 raise ValueError('invalid int value - %r' % (item,))
207 return file, a2b_hex(self.format_str % (item,))[::self.step]
209 class IPV6AddressType(Type):
210 def read(self, file):
211 data, file = read(file, 16)
212 if data[:12] == '00000000000000000000ffff'.decode('hex'):
213 return '.'.join(str(ord(x)) for x in data[12:]), file
214 return ':'.join(data[i*2:(i+1)*2].encode('hex') for i in xrange(8)), file
216 def write(self, file, item):
218 data = ''.join(item.replace(':', '')).decode('hex')
220 bits = map(int, item.split('.'))
222 raise ValueError('invalid address: %r' % (bits,))
223 data = '00000000000000000000ffff'.decode('hex') + ''.join(chr(x) for x in bits)
224 assert len(data) == 16, len(data)
229 def get_record(fields):
230 fields = tuple(sorted(fields))
233 if fields not in _record_types:
234 class _Record(object):
237 return repr(dict(self))
238 def __getitem__(self, key):
239 return getattr(self, key)
240 def __setitem__(self, key, value):
241 setattr(self, key, value)
243 # for field in self.__slots__:
244 # yield field, getattr(self, field)
246 return self.__slots__
247 def get(self, key, default=None):
248 return getattr(self, key, default)
249 def __eq__(self, other):
250 if isinstance(other, dict):
251 return dict(self) == other
252 elif isinstance(other, _Record):
253 return all(self[k] == other[k] for k in self.keys())
257 def __ne__(self, other):
258 return not (self == other)
259 _record_types[fields] = _Record
260 return _record_types[fields]()
262 class ComposedType(Type):
263 def __init__(self, fields):
264 self.fields = tuple(fields)
265 self.field_names = set(k for k, v in fields)
267 def read(self, file):
268 item = get_record(k for k, v in self.fields)
269 for key, type_ in self.fields:
270 item[key], file = type_.read(file)
273 def write(self, file, item):
274 assert set(item.keys()) == self.field_names, (set(item.keys()) - self.field_names, self.field_names - set(item.keys()))
275 for key, type_ in self.fields:
276 file = type_.write(file, item[key])
279 class PossiblyNoneType(Type):
280 def __init__(self, none_value, inner):
281 self.none_value = none_value
284 def read(self, file):
285 value, file = self.inner.read(file)
286 return None if value == self.none_value else value, file
288 def write(self, file, item):
289 if item == self.none_value:
290 raise ValueError('none_value used')
291 return self.inner.write(file, self.none_value if item is None else item)
293 class FixedStrType(Type):
294 def __init__(self, length):
297 def read(self, file):
298 return read(file, self.length)
300 def write(self, file, item):
301 if len(item) != self.length:
302 raise ValueError('incorrect length item!')