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, values):
127 for k, v in values.iteritems():
129 raise ValueError('duplicate value in values')
133 def read(self, file):
134 data, file = self.inner.read(file)
135 if data not in self.keys:
136 raise ValueError('enum data (%r) not in values (%r)' % (data, self.values))
137 return self.keys[data], file
139 def write(self, file, item):
140 if item not in self.values:
141 raise ValueError('enum item (%r) not in values (%r)' % (item, self.values))
142 return self.inner.write(file, self.values[item])
144 class ListType(Type):
145 _inner_size = VarIntType()
147 def __init__(self, type):
150 def read(self, file):
151 length, file = self._inner_size.read(file)
153 for i in xrange(length):
154 item, file = self.type.read(file)
158 def write(self, file, item):
159 file = self._inner_size.write(file, len(item))
161 file = self.type.write(file, subitem)
164 class StructType(Type):
165 __slots__ = 'desc length'.split(' ')
167 def __init__(self, desc):
169 self.length = struct.calcsize(self.desc)
171 def read(self, file):
172 data, file = read(file, self.length)
173 return struct.unpack(self.desc, data)[0], file
175 def write(self, file, item):
176 return file, struct.pack(self.desc, item)
179 __slots__ = 'bytes step format_str max'.split(' ')
181 def __new__(cls, bits, endianness='little'):
183 assert endianness in ['little', 'big']
184 if bits in [8, 16, 32, 64]:
185 return StructType(('<' if endianness == 'little' else '>') + {8: 'B', 16: 'H', 32: 'I', 64: 'Q'}[bits])
187 return Type.__new__(cls, bits, endianness)
189 def __init__(self, bits, endianness='little'):
191 assert endianness in ['little', 'big']
193 self.step = -1 if endianness == 'little' else 1
194 self.format_str = '%%0%ix' % (2*self.bytes)
197 def read(self, file, b2a_hex=binascii.b2a_hex):
200 data, file = read(file, self.bytes)
201 return int(b2a_hex(data[::self.step]), 16), file
203 def write(self, file, item, a2b_hex=binascii.a2b_hex):
206 if not 0 <= item < self.max:
207 raise ValueError('invalid int value - %r' % (item,))
208 return file, a2b_hex(self.format_str % (item,))[::self.step]
210 class IPV6AddressType(Type):
211 def read(self, file):
212 data, file = read(file, 16)
213 if data[:12] != '00000000000000000000ffff'.decode('hex'):
214 raise ValueError('ipv6 addresses not supported yet')
215 return '.'.join(str(ord(x)) for x in data[12:]), file
217 def write(self, file, item):
218 bits = map(int, item.split('.'))
220 raise ValueError('invalid address: %r' % (bits,))
221 data = '00000000000000000000ffff'.decode('hex') + ''.join(chr(x) for x in bits)
222 assert len(data) == 16, len(data)
227 def get_record(fields):
228 fields = tuple(sorted(fields))
231 if fields not in _record_types:
232 class _Record(object):
235 return repr(dict(self))
236 def __getitem__(self, key):
237 return getattr(self, key)
238 def __setitem__(self, key, value):
239 setattr(self, key, value)
241 # for field in self.__slots__:
242 # yield field, getattr(self, field)
244 return self.__slots__
245 def get(self, key, default=None):
246 return getattr(self, key, default)
247 def __eq__(self, other):
248 if isinstance(other, dict):
249 return dict(self) == other
250 elif isinstance(other, _Record):
251 return all(self[k] == other[k] for k in self.keys())
253 def __ne__(self, other):
254 return not (self == other)
255 _record_types[fields] = _Record
256 return _record_types[fields]()
258 class ComposedType(Type):
259 def __init__(self, fields):
260 self.fields = tuple(fields)
261 self.field_names = set(k for k, v in fields)
263 def read(self, file):
264 item = get_record(k for k, v in self.fields)
265 for key, type_ in self.fields:
266 item[key], file = type_.read(file)
269 def write(self, file, item):
270 assert set(item.keys()) == self.field_names, (set(item.keys()) - self.field_names, self.field_names - set(item.keys()))
271 for key, type_ in self.fields:
272 file = type_.write(file, item[key])
275 class PossiblyNoneType(Type):
276 def __init__(self, none_value, inner):
277 self.none_value = none_value
280 def read(self, file):
281 value, file = self.inner.read(file)
282 return None if value == self.none_value else value, file
284 def write(self, file, item):
285 if item == self.none_value:
286 raise ValueError('none_value used')
287 return self.inner.write(file, self.none_value if item is None else item)
289 class FixedStrType(Type):
290 def __init__(self, length):
293 def read(self, file):
294 return read(file, self.length)
296 def write(self, file, item):
297 if len(item) != self.length:
298 raise ValueError('incorrect length item!')