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 data2 = self._pack(obj)
67 if self._unpack(data2) != obj:
68 raise AssertionError()
73 data = self._pack(obj)
76 if self._unpack(data) != obj:
77 raise AssertionError((self._unpack(data), obj))
81 class VarIntType(Type):
83 data, file = read(file, 1)
88 desc, length, minimum = '<H', 2, 0xfd
90 desc, length, minimum = '<I', 4, 2**16
92 desc, length, minimum = '<Q', 8, 2**32
94 raise AssertionError()
95 data2, file = read(file, length)
96 res, = struct.unpack(desc, data2)
98 raise AssertionError('VarInt not canonically packed')
101 def write(self, file, item):
103 return file, struct.pack('<B', item)
105 return file, struct.pack('<BH', 0xfd, item)
106 elif item <= 0xffffffff:
107 return file, struct.pack('<BI', 0xfe, item)
108 elif item <= 0xffffffffffffffff:
109 return file, struct.pack('<BQ', 0xff, item)
111 raise ValueError('int too large for varint')
113 class VarStrType(Type):
114 _inner_size = VarIntType()
116 def read(self, file):
117 length, file = self._inner_size.read(file)
118 return read(file, length)
120 def write(self, file, item):
121 return self._inner_size.write(file, len(item)), item
123 class EnumType(Type):
124 def __init__(self, inner, values):
129 for k, v in values.iteritems():
131 raise ValueError('duplicate value in values')
135 def read(self, file):
136 data, file = self.inner.read(file)
137 if data not in self.keys:
138 raise ValueError('enum data (%r) not in values (%r)' % (data, self.values))
139 return self.keys[data], file
141 def write(self, file, item):
142 if item not in self.values:
143 raise ValueError('enum item (%r) not in values (%r)' % (item, self.values))
144 return self.inner.write(file, self.values[item])
146 class ListType(Type):
147 _inner_size = VarIntType()
149 def __init__(self, type):
152 def read(self, file):
153 length, file = self._inner_size.read(file)
155 for i in xrange(length):
156 item, file = self.type.read(file)
160 def write(self, file, item):
161 file = self._inner_size.write(file, len(item))
163 file = self.type.write(file, subitem)
166 class StructType(Type):
167 __slots__ = 'desc length'.split(' ')
169 def __init__(self, desc):
171 self.length = struct.calcsize(self.desc)
173 def read(self, file):
174 data, file = read(file, self.length)
175 return struct.unpack(self.desc, data)[0], file
177 def write(self, file, item):
178 return file, struct.pack(self.desc, item)
181 __slots__ = 'bytes step format_str max'.split(' ')
183 def __new__(cls, bits, endianness='little'):
185 assert endianness in ['little', 'big']
186 if bits in [8, 16, 32, 64]:
187 return StructType(('<' if endianness == 'little' else '>') + {8: 'B', 16: 'H', 32: 'I', 64: 'Q'}[bits])
189 return Type.__new__(cls, bits, endianness)
191 def __init__(self, bits, endianness='little'):
193 assert endianness in ['little', 'big']
195 self.step = -1 if endianness == 'little' else 1
196 self.format_str = '%%0%ix' % (2*self.bytes)
199 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):
204 if not 0 <= item < self.max:
205 raise ValueError('invalid int value - %r' % (item,))
206 return file, a2b_hex(self.format_str % (item,))[::self.step]
208 class IPV6AddressType(Type):
209 def read(self, file):
210 data, file = read(file, 16)
211 if data[:12] != '00000000000000000000ffff'.decode('hex'):
212 raise ValueError('ipv6 addresses not supported yet')
213 return '.'.join(str(ord(x)) for x in data[12:]), file
215 def write(self, file, item):
216 bits = map(int, item.split('.'))
218 raise ValueError('invalid address: %r' % (bits,))
219 data = '00000000000000000000ffff'.decode('hex') + ''.join(chr(x) for x in bits)
220 assert len(data) == 16, len(data)
225 def get_record(fields):
226 fields = tuple(sorted(fields))
229 if fields not in _record_types:
230 class _Record(object):
233 return repr(dict(self))
234 def __getitem__(self, key):
235 return getattr(self, key)
236 def __setitem__(self, key, value):
237 setattr(self, key, value)
239 # for field in self.__slots__:
240 # yield field, getattr(self, field)
242 return self.__slots__
243 def __eq__(self, other):
244 if isinstance(other, dict):
245 return dict(self) == other
246 elif isinstance(other, _Record):
247 return all(self[k] == other[k] for k in self.keys())
249 def __ne__(self, other):
250 return not (self == other)
251 _record_types[fields] = _Record
252 return _record_types[fields]()
254 class ComposedType(Type):
255 def __init__(self, fields):
256 self.fields = tuple(fields)
258 def read(self, file):
259 item = get_record(k for k, v in self.fields)
260 for key, type_ in self.fields:
261 item[key], file = type_.read(file)
264 def write(self, file, item):
265 for key, type_ in self.fields:
266 file = type_.write(file, item[key])
269 class PossiblyNoneType(Type):
270 def __init__(self, none_value, inner):
271 self.none_value = none_value
274 def read(self, file):
275 value, file = self.inner.read(file)
276 return None if value == self.none_value else value, file
278 def write(self, file, item):
279 if item == self.none_value:
280 raise ValueError('none_value used')
281 return self.inner.write(file, self.none_value if item is None else item)