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 def packed_size(self, obj):
80 if hasattr(obj, '_packed_size') and obj._packed_size is not None:
81 type_obj, packed_size = obj._packed_size
85 packed_size = len(self.pack(obj))
87 if hasattr(obj, '_packed_size'):
88 obj._packed_size = self, packed_size
92 class VarIntType(Type):
94 data, file = read(file, 1)
99 desc, length, minimum = '<H', 2, 0xfd
101 desc, length, minimum = '<I', 4, 2**16
103 desc, length, minimum = '<Q', 8, 2**32
105 raise AssertionError()
106 data2, file = read(file, length)
107 res, = struct.unpack(desc, data2)
109 raise AssertionError('VarInt not canonically packed')
112 def write(self, file, item):
114 return file, struct.pack('<B', item)
116 return file, struct.pack('<BH', 0xfd, item)
117 elif item <= 0xffffffff:
118 return file, struct.pack('<BI', 0xfe, item)
119 elif item <= 0xffffffffffffffff:
120 return file, struct.pack('<BQ', 0xff, item)
122 raise ValueError('int too large for varint')
124 class VarStrType(Type):
125 _inner_size = VarIntType()
127 def read(self, file):
128 length, file = self._inner_size.read(file)
129 return read(file, length)
131 def write(self, file, item):
132 return self._inner_size.write(file, len(item)), item
134 class EnumType(Type):
135 def __init__(self, inner, pack_to_unpack):
137 self.pack_to_unpack = pack_to_unpack
139 self.unpack_to_pack = {}
140 for k, v in pack_to_unpack.iteritems():
141 if v in self.unpack_to_pack:
142 raise ValueError('duplicate value in pack_to_unpack')
143 self.unpack_to_pack[v] = k
145 def read(self, file):
146 data, file = self.inner.read(file)
147 if data not in self.pack_to_unpack:
148 raise ValueError('enum data (%r) not in pack_to_unpack (%r)' % (data, self.pack_to_unpack))
149 return self.pack_to_unpack[data], file
151 def write(self, file, item):
152 if item not in self.unpack_to_pack:
153 raise ValueError('enum item (%r) not in unpack_to_pack (%r)' % (item, self.unpack_to_pack))
154 return self.inner.write(file, self.unpack_to_pack[item])
156 class ListType(Type):
157 _inner_size = VarIntType()
159 def __init__(self, type):
162 def read(self, file):
163 length, file = self._inner_size.read(file)
165 for i in xrange(length):
166 item, file = self.type.read(file)
170 def write(self, file, item):
171 file = self._inner_size.write(file, len(item))
173 file = self.type.write(file, subitem)
176 class StructType(Type):
177 __slots__ = 'desc length'.split(' ')
179 def __init__(self, desc):
181 self.length = struct.calcsize(self.desc)
183 def read(self, file):
184 data, file = read(file, self.length)
185 return struct.unpack(self.desc, data)[0], file
187 def write(self, file, item):
188 return file, struct.pack(self.desc, item)
191 __slots__ = 'bytes step format_str max'.split(' ')
193 def __new__(cls, bits, endianness='little'):
195 assert endianness in ['little', 'big']
196 if bits in [8, 16, 32, 64]:
197 return StructType(('<' if endianness == 'little' else '>') + {8: 'B', 16: 'H', 32: 'I', 64: 'Q'}[bits])
199 return Type.__new__(cls, bits, endianness)
201 def __init__(self, bits, endianness='little'):
203 assert endianness in ['little', 'big']
205 self.step = -1 if endianness == 'little' else 1
206 self.format_str = '%%0%ix' % (2*self.bytes)
209 def read(self, file, b2a_hex=binascii.b2a_hex):
212 data, file = read(file, self.bytes)
213 return int(b2a_hex(data[::self.step]), 16), file
215 def write(self, file, item, a2b_hex=binascii.a2b_hex):
218 if not 0 <= item < self.max:
219 raise ValueError('invalid int value - %r' % (item,))
220 return file, a2b_hex(self.format_str % (item,))[::self.step]
222 class IPV6AddressType(Type):
223 def read(self, file):
224 data, file = read(file, 16)
225 if data[:12] == '00000000000000000000ffff'.decode('hex'):
226 return '.'.join(str(ord(x)) for x in data[12:]), file
227 return ':'.join(data[i*2:(i+1)*2].encode('hex') for i in xrange(8)), file
229 def write(self, file, item):
231 data = ''.join(item.replace(':', '')).decode('hex')
233 bits = map(int, item.split('.'))
235 raise ValueError('invalid address: %r' % (bits,))
236 data = '00000000000000000000ffff'.decode('hex') + ''.join(chr(x) for x in bits)
237 assert len(data) == 16, len(data)
242 def get_record(fields):
243 fields = tuple(sorted(fields))
244 if 'keys' in fields or '_packed_size' in fields:
246 if fields not in _record_types:
247 class _Record(object):
248 __slots__ = fields + ('_packed_size',)
250 self._packed_size = None
252 return repr(dict(self))
253 def __getitem__(self, key):
254 return getattr(self, key)
255 def __setitem__(self, key, value):
256 setattr(self, key, value)
258 # for field in fields:
259 # yield field, getattr(self, field)
262 def get(self, key, default=None):
263 return getattr(self, key, default)
264 def __eq__(self, other):
265 if isinstance(other, dict):
266 return dict(self) == other
267 elif isinstance(other, _Record):
269 if getattr(self, k) != getattr(other, k):
275 def __ne__(self, other):
276 return not (self == other)
277 _record_types[fields] = _Record
278 return _record_types[fields]
280 class ComposedType(Type):
281 def __init__(self, fields):
282 self.fields = list(fields)
283 self.field_names = set(k for k, v in fields)
284 self.record_type = get_record(k for k, v in self.fields)
286 def read(self, file):
287 item = self.record_type()
288 for key, type_ in self.fields:
289 item[key], file = type_.read(file)
292 def write(self, file, item):
293 assert set(item.keys()) == self.field_names, (set(item.keys()) - self.field_names, self.field_names - set(item.keys()))
294 for key, type_ in self.fields:
295 file = type_.write(file, item[key])
298 class PossiblyNoneType(Type):
299 def __init__(self, none_value, inner):
300 self.none_value = none_value
303 def read(self, file):
304 value, file = self.inner.read(file)
305 return None if value == self.none_value else value, file
307 def write(self, file, item):
308 if item == self.none_value:
309 raise ValueError('none_value used')
310 return self.inner.write(file, self.none_value if item is None else item)
312 class FixedStrType(Type):
313 def __init__(self, length):
316 def read(self, file):
317 return read(file, self.length)
319 def write(self, file, item):
320 if len(item) != self.length:
321 raise ValueError('incorrect length item!')