_ Git - youtube-dl/blob - youtube_dl/swfinterp.py

   1 from __future__ import unicode_literals
   2
   3 import collections
   4 import io
   5 import zlib
   6
   7 from .utils import (
   8     compat_str,
   9     ExtractorError,
  10     struct_unpack,
  11 )
  12
  13
  14 def _extract_tags(file_contents):
  15     if file_contents[1:3] != b'WS':
  16         raise ExtractorError(
  17             'Not an SWF file; header is %r' % file_contents[:3])
  18     if file_contents[:1] == b'C':
  19         content = zlib.decompress(file_contents[8:])
  20     else:
  21         raise NotImplementedError(
  22             'Unsupported compression format %r' %
  23             file_contents[:1])
  24
  25     # Determine number of bits in framesize rectangle
  26     framesize_nbits = struct_unpack('!B', content[:1])[0] >> 3
  27     framesize_len = (5 + 4 * framesize_nbits + 7) // 8
  28
  29     pos = framesize_len + 2 + 2
  30     while pos < len(content):
  31         header16 = struct_unpack('<H', content[pos:pos + 2])[0]
  32         pos += 2
  33         tag_code = header16 >> 6
  34         tag_len = header16 & 0x3f
  35         if tag_len == 0x3f:
  36             tag_len = struct_unpack('<I', content[pos:pos + 4])[0]
  37             pos += 4
  38         assert pos + tag_len <= len(content), \
  39             ('Tag %d ends at %d+%d - that\'s longer than the file (%d)'
  40                 % (tag_code, pos, tag_len, len(content)))
  41         yield (tag_code, content[pos:pos + tag_len])
  42         pos += tag_len
  43
  44
  45 class _AVMClass_Object(object):
  46     def __init__(self, avm_class):
  47         self.avm_class = avm_class
  48
  49     def __repr__(self):
  50         return '%s#%x' % (self.avm_class.name, id(self))
  51
  52
  53 class _ScopeDict(dict):
  54     def __init__(self, avm_class):
  55         super(_ScopeDict, self).__init__()
  56         self.avm_class = avm_class
  57
  58     def __repr__(self):
  59         return '%s__Scope(%s)' % (
  60             self.avm_class.name,
  61             super(_ScopeDict, self).__repr__())
  62
  63
  64 class _AVMClass(object):
  65     def __init__(self, name_idx, name):
  66         self.name_idx = name_idx
  67         self.name = name
  68         self.method_names = {}
  69         self.method_idxs = {}
  70         self.methods = {}
  71         self.method_pyfunctions = {}
  72
  73         self.variables = _ScopeDict(self)
  74
  75     def make_object(self):
  76         return _AVMClass_Object(self)
  77
  78     def __repr__(self):
  79         return '_AVMClass(%s)' % (self.name)
  80
  81     def register_methods(self, methods):
  82         self.method_names.update(methods.items())
  83         self.method_idxs.update(dict(
  84             (idx, name)
  85             for name, idx in methods.items()))
  86
  87
  88 class _Multiname(object):
  89     def __init__(self, kind):
  90         self.kind = kind
  91
  92     def __repr__(self):
  93         return '[MULTINAME kind: 0x%x]' % self.kind
  94
  95
  96 def _read_int(reader):
  97     res = 0
  98     shift = 0
  99     for _ in range(5):
 100         buf = reader.read(1)
 101         assert len(buf) == 1
 102         b = struct_unpack('<B', buf)[0]
 103         res = res | ((b & 0x7f) << shift)
 104         if b & 0x80 == 0:
 105             break
 106         shift += 7
 107     return res
 108
 109
 110 def _u30(reader):
 111     res = _read_int(reader)
 112     assert res & 0xf0000000 == 0
 113     return res
 114 _u32 = _read_int
 115
 116
 117 def _s32(reader):
 118     v = _read_int(reader)
 119     if v & 0x80000000 != 0:
 120         v = - ((v ^ 0xffffffff) + 1)
 121     return v
 122
 123
 124 def _s24(reader):
 125     bs = reader.read(3)
 126     assert len(bs) == 3
 127     last_byte = b'\xff' if (ord(bs[2:3]) >= 0x80) else b'\x00'
 128     return struct_unpack('<i', bs + last_byte)[0]
 129
 130
 131 def _read_string(reader):
 132     slen = _u30(reader)
 133     resb = reader.read(slen)
 134     assert len(resb) == slen
 135     return resb.decode('utf-8')
 136
 137
 138 def _read_bytes(count, reader):
 139     assert count >= 0
 140     resb = reader.read(count)
 141     assert len(resb) == count
 142     return resb
 143
 144
 145 def _read_byte(reader):
 146     resb = _read_bytes(1, reader=reader)
 147     res = struct_unpack('<B', resb)[0]
 148     return res
 149
 150
 151 StringClass = _AVMClass('(no name idx)', 'String')
 152
 153
 154 class _Undefined(object):
 155     def __boolean__(self):
 156         return False
 157
 158     def __hash__(self):
 159         return 0
 160
 161 undefined = _Undefined()
 162
 163
 164 class SWFInterpreter(object):
 165     def __init__(self, file_contents):
 166         self._patched_functions = {}
 167         code_tag = next(tag
 168                         for tag_code, tag in _extract_tags(file_contents)
 169                         if tag_code == 82)
 170         p = code_tag.index(b'\0', 4) + 1
 171         code_reader = io.BytesIO(code_tag[p:])
 172
 173         # Parse ABC (AVM2 ByteCode)
 174
 175         # Define a couple convenience methods
 176         u30 = lambda *args: _u30(*args, reader=code_reader)
 177         s32 = lambda *args: _s32(*args, reader=code_reader)
 178         u32 = lambda *args: _u32(*args, reader=code_reader)
 179         read_bytes = lambda *args: _read_bytes(*args, reader=code_reader)
 180         read_byte = lambda *args: _read_byte(*args, reader=code_reader)
 181
 182         # minor_version + major_version
 183         read_bytes(2 + 2)
 184
 185         # Constant pool
 186         int_count = u30()
 187         for _c in range(1, int_count):
 188             s32()
 189         uint_count = u30()
 190         for _c in range(1, uint_count):
 191             u32()
 192         double_count = u30()
 193         read_bytes(max(0, (double_count - 1)) * 8)
 194         string_count = u30()
 195         self.constant_strings = ['']
 196         for _c in range(1, string_count):
 197             s = _read_string(code_reader)
 198             self.constant_strings.append(s)
 199         namespace_count = u30()
 200         for _c in range(1, namespace_count):
 201             read_bytes(1)  # kind
 202             u30()  # name
 203         ns_set_count = u30()
 204         for _c in range(1, ns_set_count):
 205             count = u30()
 206             for _c2 in range(count):
 207                 u30()
 208         multiname_count = u30()
 209         MULTINAME_SIZES = {
 210             0x07: 2,  # QName
 211             0x0d: 2,  # QNameA
 212             0x0f: 1,  # RTQName
 213             0x10: 1,  # RTQNameA
 214             0x11: 0,  # RTQNameL
 215             0x12: 0,  # RTQNameLA
 216             0x09: 2,  # Multiname
 217             0x0e: 2,  # MultinameA
 218             0x1b: 1,  # MultinameL
 219             0x1c: 1,  # MultinameLA
 220         }
 221         self.multinames = ['']
 222         for _c in range(1, multiname_count):
 223             kind = u30()
 224             assert kind in MULTINAME_SIZES, 'Invalid multiname kind %r' % kind
 225             if kind == 0x07:
 226                 u30()  # namespace_idx
 227                 name_idx = u30()
 228                 self.multinames.append(self.constant_strings[name_idx])
 229             elif kind == 0x09:
 230                 name_idx = u30()
 231                 u30()
 232                 self.multinames.append(self.constant_strings[name_idx])
 233             else:
 234                 self.multinames.append(_Multiname(kind))
 235                 for _c2 in range(MULTINAME_SIZES[kind]):
 236                     u30()
 237
 238         # Methods
 239         method_count = u30()
 240         MethodInfo = collections.namedtuple(
 241             'MethodInfo',
 242             ['NEED_ARGUMENTS', 'NEED_REST'])
 243         method_infos = []
 244         for method_id in range(method_count):
 245             param_count = u30()
 246             u30()  # return type
 247             for _ in range(param_count):
 248                 u30()  # param type
 249             u30()  # name index (always 0 for youtube)
 250             flags = read_byte()
 251             if flags & 0x08 != 0:
 252                 # Options present
 253                 option_count = u30()
 254                 for c in range(option_count):
 255                     u30()  # val
 256                     read_bytes(1)  # kind
 257             if flags & 0x80 != 0:
 258                 # Param names present
 259                 for _ in range(param_count):
 260                     u30()  # param name
 261             mi = MethodInfo(flags & 0x01 != 0, flags & 0x04 != 0)
 262             method_infos.append(mi)
 263
 264         # Metadata
 265         metadata_count = u30()
 266         for _c in range(metadata_count):
 267             u30()  # name
 268             item_count = u30()
 269             for _c2 in range(item_count):
 270                 u30()  # key
 271                 u30()  # value
 272
 273         def parse_traits_info():
 274             trait_name_idx = u30()
 275             kind_full = read_byte()
 276             kind = kind_full & 0x0f
 277             attrs = kind_full >> 4
 278             methods = {}
 279             if kind in [0x00, 0x06]:  # Slot or Const
 280                 u30()  # Slot id
 281                 u30()  # type_name_idx
 282                 vindex = u30()
 283                 if vindex != 0:
 284                     read_byte()  # vkind
 285             elif kind in [0x01, 0x02, 0x03]:  # Method / Getter / Setter
 286                 u30()  # disp_id
 287                 method_idx = u30()
 288                 methods[self.multinames[trait_name_idx]] = method_idx
 289             elif kind == 0x04:  # Class
 290                 u30()  # slot_id
 291                 u30()  # classi
 292             elif kind == 0x05:  # Function
 293                 u30()  # slot_id
 294                 function_idx = u30()
 295                 methods[function_idx] = self.multinames[trait_name_idx]
 296             else:
 297                 raise ExtractorError('Unsupported trait kind %d' % kind)
 298
 299             if attrs & 0x4 != 0:  # Metadata present
 300                 metadata_count = u30()
 301                 for _c3 in range(metadata_count):
 302                     u30()  # metadata index
 303
 304             return methods
 305
 306         # Classes
 307         class_count = u30()
 308         classes = []
 309         for class_id in range(class_count):
 310             name_idx = u30()
 311
 312             cname = self.multinames[name_idx]
 313             avm_class = _AVMClass(name_idx, cname)
 314             classes.append(avm_class)
 315
 316             u30()  # super_name idx
 317             flags = read_byte()
 318             if flags & 0x08 != 0:  # Protected namespace is present
 319                 u30()  # protected_ns_idx
 320             intrf_count = u30()
 321             for _c2 in range(intrf_count):
 322                 u30()
 323             u30()  # iinit
 324             trait_count = u30()
 325             for _c2 in range(trait_count):
 326                 trait_methods = parse_traits_info()
 327                 avm_class.register_methods(trait_methods)
 328
 329         assert len(classes) == class_count
 330         self._classes_by_name = dict((c.name, c) for c in classes)
 331
 332         for avm_class in classes:
 333             u30()  # cinit
 334             trait_count = u30()
 335             for _c2 in range(trait_count):
 336                 trait_methods = parse_traits_info()
 337                 avm_class.register_methods(trait_methods)
 338
 339         # Scripts
 340         script_count = u30()
 341         for _c in range(script_count):
 342             u30()  # init
 343             trait_count = u30()
 344             for _c2 in range(trait_count):
 345                 parse_traits_info()
 346
 347         # Method bodies
 348         method_body_count = u30()
 349         Method = collections.namedtuple('Method', ['code', 'local_count'])
 350         for _c in range(method_body_count):
 351             method_idx = u30()
 352             u30()  # max_stack
 353             local_count = u30()
 354             u30()  # init_scope_depth
 355             u30()  # max_scope_depth
 356             code_length = u30()
 357             code = read_bytes(code_length)
 358             for avm_class in classes:
 359                 if method_idx in avm_class.method_idxs:
 360                     m = Method(code, local_count)
 361                     avm_class.methods[avm_class.method_idxs[method_idx]] = m
 362             exception_count = u30()
 363             for _c2 in range(exception_count):
 364                 u30()  # from
 365                 u30()  # to
 366                 u30()  # target
 367                 u30()  # exc_type
 368                 u30()  # var_name
 369             trait_count = u30()
 370             for _c2 in range(trait_count):
 371                 parse_traits_info()
 372
 373         assert p + code_reader.tell() == len(code_tag)
 374
 375     def patch_function(self, avm_class, func_name, f):
 376         self._patched_functions[(avm_class, func_name)] = f
 377
 378     def extract_class(self, class_name):
 379         try:
 380             return self._classes_by_name[class_name]
 381         except KeyError:
 382             raise ExtractorError('Class %r not found' % class_name)
 383
 384     def extract_function(self, avm_class, func_name):
 385         p = self._patched_functions.get((avm_class, func_name))
 386         if p:
 387             return p
 388         if func_name in avm_class.method_pyfunctions:
 389             return avm_class.method_pyfunctions[func_name]
 390         if func_name in self._classes_by_name:
 391             return self._classes_by_name[func_name].make_object()
 392         if func_name not in avm_class.methods:
 393             raise ExtractorError('Cannot find function %s.%s' % (
 394                 avm_class.name, func_name))
 395         m = avm_class.methods[func_name]
 396
 397         def resfunc(args):
 398             # Helper functions
 399             coder = io.BytesIO(m.code)
 400             s24 = lambda: _s24(coder)
 401             u30 = lambda: _u30(coder)
 402
 403             registers = [avm_class.variables] + list(args) + [None] * m.local_count
 404             stack = []
 405             scopes = collections.deque([
 406                 self._classes_by_name, avm_class.variables])
 407             while True:
 408                 opcode = _read_byte(coder)
 409                 if opcode == 16:  # jump
 410                     offset = s24()
 411                     coder.seek(coder.tell() + offset)
 412                 elif opcode == 17:  # iftrue
 413                     offset = s24()
 414                     value = stack.pop()
 415                     if value:
 416                         coder.seek(coder.tell() + offset)
 417                 elif opcode == 18:  # iffalse
 418                     offset = s24()
 419                     value = stack.pop()
 420                     if not value:
 421                         coder.seek(coder.tell() + offset)
 422                 elif opcode == 19:  # ifeq
 423                     offset = s24()
 424                     value2 = stack.pop()
 425                     value1 = stack.pop()
 426                     if value2 == value1:
 427                         coder.seek(coder.tell() + offset)
 428                 elif opcode == 20:  # ifne
 429                     offset = s24()
 430                     value2 = stack.pop()
 431                     value1 = stack.pop()
 432                     if value2 != value1:
 433                         coder.seek(coder.tell() + offset)
 434                 elif opcode == 32:  # pushnull
 435                     stack.append(None)
 436                 elif opcode == 33:  # pushundefined
 437                     stack.append(undefined)
 438                 elif opcode == 36:  # pushbyte
 439                     v = _read_byte(coder)
 440                     stack.append(v)
 441                 elif opcode == 38:  # pushtrue
 442                     stack.append(True)
 443                 elif opcode == 39:  # pushfalse
 444                     stack.append(False)
 445                 elif opcode == 40:  # pushnan
 446                     stack.append(float('NaN'))
 447                 elif opcode == 42:  # dup
 448                     value = stack[-1]
 449                     stack.append(value)
 450                 elif opcode == 44:  # pushstring
 451                     idx = u30()
 452                     stack.append(self.constant_strings[idx])
 453                 elif opcode == 48:  # pushscope
 454                     new_scope = stack.pop()
 455                     scopes.append(new_scope)
 456                 elif opcode == 66:  # construct
 457                     arg_count = u30()
 458                     args = list(reversed(
 459                         [stack.pop() for _ in range(arg_count)]))
 460                     obj = stack.pop()
 461                     res = obj.avm_class.make_object()
 462                     stack.append(res)
 463                 elif opcode == 70:  # callproperty
 464                     index = u30()
 465                     mname = self.multinames[index]
 466                     arg_count = u30()
 467                     args = list(reversed(
 468                         [stack.pop() for _ in range(arg_count)]))
 469                     obj = stack.pop()
 470
 471                     if isinstance(obj, _AVMClass_Object):
 472                         func = self.extract_function(obj.avm_class, mname)
 473                         res = func(args)
 474                         stack.append(res)
 475                         continue
 476                     elif isinstance(obj, _ScopeDict):
 477                         if mname in obj.avm_class.method_names:
 478                             func = self.extract_function(obj.avm_class, mname)
 479                             res = func(args)
 480                         else:
 481                             res = obj[mname]
 482                         stack.append(res)
 483                         continue
 484                     elif isinstance(obj, compat_str):
 485                         if mname == 'split':
 486                             assert len(args) == 1
 487                             assert isinstance(args[0], compat_str)
 488                             if args[0] == '':
 489                                 res = list(obj)
 490                             else:
 491                                 res = obj.split(args[0])
 492                             stack.append(res)
 493                             continue
 494                     elif isinstance(obj, list):
 495                         if mname == 'slice':
 496                             assert len(args) == 1
 497                             assert isinstance(args[0], int)
 498                             res = obj[args[0]:]
 499                             stack.append(res)
 500                             continue
 501                         elif mname == 'join':
 502                             assert len(args) == 1
 503                             assert isinstance(args[0], compat_str)
 504                             res = args[0].join(obj)
 505                             stack.append(res)
 506                             continue
 507                     elif obj == StringClass:
 508                         if mname == 'String':
 509                             assert len(args) == 1
 510                             assert isinstance(args[0], (
 511                                 int, compat_str, _Undefined))
 512                             if args[0] == undefined:
 513                                 res = 'undefined'
 514                             else:
 515                                 res = compat_str(args[0])
 516                             stack.append(res)
 517                             continue
 518                         else:
 519                             raise NotImplementedError(
 520                                 'Function String.%s is not yet implemented'
 521                                 % mname)
 522                     raise NotImplementedError(
 523                         'Unsupported property %r on %r'
 524                         % (mname, obj))
 525                 elif opcode == 71:  # returnvoid
 526                     res = undefined
 527                     return res
 528                 elif opcode == 72:  # returnvalue
 529                     res = stack.pop()
 530                     return res
 531                 elif opcode == 74:  # constructproperty
 532                     index = u30()
 533                     arg_count = u30()
 534                     args = list(reversed(
 535                         [stack.pop() for _ in range(arg_count)]))
 536                     obj = stack.pop()
 537
 538                     mname = self.multinames[index]
 539                     assert isinstance(obj, _AVMClass)
 540
 541                     # We do not actually call the constructor for now;
 542                     # we just pretend it does nothing
 543                     stack.append(obj.make_object())
 544                 elif opcode == 79:  # callpropvoid
 545                     index = u30()
 546                     mname = self.multinames[index]
 547                     arg_count = u30()
 548                     args = list(reversed(
 549                         [stack.pop() for _ in range(arg_count)]))
 550                     obj = stack.pop()
 551                     if isinstance(obj, _AVMClass_Object):
 552                         func = self.extract_function(obj.avm_class, mname)
 553                         res = func(args)
 554                         assert res is undefined
 555                         continue
 556                     if isinstance(obj, _ScopeDict):
 557                         assert mname in obj.avm_class.method_names
 558                         func = self.extract_function(obj.avm_class, mname)
 559                         res = func(args)
 560                         assert res is undefined
 561                         continue
 562                     if mname == 'reverse':
 563                         assert isinstance(obj, list)
 564                         obj.reverse()
 565                     else:
 566                         raise NotImplementedError(
 567                             'Unsupported (void) property %r on %r'
 568                             % (mname, obj))
 569                 elif opcode == 86:  # newarray
 570                     arg_count = u30()
 571                     arr = []
 572                     for i in range(arg_count):
 573                         arr.append(stack.pop())
 574                     arr = arr[::-1]
 575                     stack.append(arr)
 576                 elif opcode == 93:  # findpropstrict
 577                     index = u30()
 578                     mname = self.multinames[index]
 579                     for s in reversed(scopes):
 580                         if mname in s:
 581                             res = s
 582                             break
 583                     else:
 584                         res = scopes[0]
 585                     if mname not in res and mname == 'String':
 586                         stack.append(StringClass)
 587                     else:
 588                         stack.append(res[mname])
 589                 elif opcode == 94:  # findproperty
 590                     index = u30()
 591                     mname = self.multinames[index]
 592                     for s in reversed(scopes):
 593                         if mname in s:
 594                             res = s
 595                             break
 596                     else:
 597                         res = avm_class.variables
 598                     stack.append(res)
 599                 elif opcode == 96:  # getlex
 600                     index = u30()
 601                     mname = self.multinames[index]
 602                     for s in reversed(scopes):
 603                         if mname in s:
 604                             scope = s
 605                             break
 606                     else:
 607                         scope = avm_class.variables
 608                     # I cannot find where static variables are initialized
 609                     # so let's just return None
 610                     res = scope.get(mname)
 611                     stack.append(res)
 612                 elif opcode == 97:  # setproperty
 613                     index = u30()
 614                     value = stack.pop()
 615                     idx = self.multinames[index]
 616                     if isinstance(idx, _Multiname):
 617                         idx = stack.pop()
 618                     obj = stack.pop()
 619                     obj[idx] = value
 620                 elif opcode == 98:  # getlocal
 621                     index = u30()
 622                     stack.append(registers[index])
 623                 elif opcode == 99:  # setlocal
 624                     index = u30()
 625                     value = stack.pop()
 626                     registers[index] = value
 627                 elif opcode == 102:  # getproperty
 628                     index = u30()
 629                     pname = self.multinames[index]
 630                     if pname == 'length':
 631                         obj = stack.pop()
 632                         assert isinstance(obj, (compat_str, list))
 633                         stack.append(len(obj))
 634                     elif isinstance(pname, compat_str):  # Member access
 635                         obj = stack.pop()
 636                         assert isinstance(obj, (dict, _ScopeDict)), \
 637                             'Accessing member %r on %r' % (pname, obj)
 638                         res = obj.get(pname, undefined)
 639                         stack.append(res)
 640                     else:  # Assume attribute access
 641                         idx = stack.pop()
 642                         assert isinstance(idx, int)
 643                         obj = stack.pop()
 644                         assert isinstance(obj, list)
 645                         stack.append(obj[idx])
 646                 elif opcode == 115:  # convert_
 647                     value = stack.pop()
 648                     intvalue = int(value)
 649                     stack.append(intvalue)
 650                 elif opcode == 128:  # coerce
 651                     u30()
 652                 elif opcode == 130:  # coerce_a
 653                     value = stack.pop()
 654                     # um, yes, it's any value
 655                     stack.append(value)
 656                 elif opcode == 133:  # coerce_s
 657                     assert isinstance(stack[-1], (type(None), compat_str))
 658                 elif opcode == 147:  # decrement
 659                     value = stack.pop()
 660                     assert isinstance(value, int)
 661                     stack.append(value - 1)
 662                 elif opcode == 149:  # typeof
 663                     value = stack.pop()
 664                     return {
 665                         _Undefined: 'undefined',
 666                         compat_str: 'String',
 667                         int: 'Number',
 668                         float: 'Number',
 669                     }[type(value)]
 670                 elif opcode == 160:  # add
 671                     value2 = stack.pop()
 672                     value1 = stack.pop()
 673                     res = value1 + value2
 674                     stack.append(res)
 675                 elif opcode == 161:  # subtract
 676                     value2 = stack.pop()
 677                     value1 = stack.pop()
 678                     res = value1 - value2
 679                     stack.append(res)
 680                 elif opcode == 164:  # modulo
 681                     value2 = stack.pop()
 682                     value1 = stack.pop()
 683                     res = value1 % value2
 684                     stack.append(res)
 685                 elif opcode == 171:  # equals
 686                     value2 = stack.pop()
 687                     value1 = stack.pop()
 688                     result = value1 == value2
 689                     stack.append(result)
 690                 elif opcode == 175:  # greaterequals
 691                     value2 = stack.pop()
 692                     value1 = stack.pop()
 693                     result = value1 >= value2
 694                     stack.append(result)
 695                 elif opcode == 208:  # getlocal_0
 696                     stack.append(registers[0])
 697                 elif opcode == 209:  # getlocal_1
 698                     stack.append(registers[1])
 699                 elif opcode == 210:  # getlocal_2
 700                     stack.append(registers[2])
 701                 elif opcode == 211:  # getlocal_3
 702                     stack.append(registers[3])
 703                 elif opcode == 212:  # setlocal_0
 704                     registers[0] = stack.pop()
 705                 elif opcode == 213:  # setlocal_1
 706                     registers[1] = stack.pop()
 707                 elif opcode == 214:  # setlocal_2
 708                     registers[2] = stack.pop()
 709                 elif opcode == 215:  # setlocal_3
 710                     registers[3] = stack.pop()
 711                 else:
 712                     raise NotImplementedError(
 713                         'Unsupported opcode %d' % opcode)
 714
 715         avm_class.method_pyfunctions[func_name] = resfunc
 716         return resfunc
 717