]> git.bitcoin.ninja Git - youtube-dl/blob - youtube_dl/swfinterp.py
Ignore and cleanup 3gp files
[youtube-dl] / youtube_dl / swfinterp.py
1 from __future__ import unicode_literals
2
3 import collections
4 import io
5 import zlib
6
7 from .compat import (
8     compat_str,
9     compat_struct_unpack,
10 )
11 from .utils import (
12     ExtractorError,
13 )
14
15
16 def _extract_tags(file_contents):
17     if file_contents[1:3] != b'WS':
18         raise ExtractorError(
19             'Not an SWF file; header is %r' % file_contents[:3])
20     if file_contents[:1] == b'C':
21         content = zlib.decompress(file_contents[8:])
22     else:
23         raise NotImplementedError(
24             'Unsupported compression format %r' %
25             file_contents[:1])
26
27     # Determine number of bits in framesize rectangle
28     framesize_nbits = compat_struct_unpack('!B', content[:1])[0] >> 3
29     framesize_len = (5 + 4 * framesize_nbits + 7) // 8
30
31     pos = framesize_len + 2 + 2
32     while pos < len(content):
33         header16 = compat_struct_unpack('<H', content[pos:pos + 2])[0]
34         pos += 2
35         tag_code = header16 >> 6
36         tag_len = header16 & 0x3f
37         if tag_len == 0x3f:
38             tag_len = compat_struct_unpack('<I', content[pos:pos + 4])[0]
39             pos += 4
40         assert pos + tag_len <= len(content), \
41             ('Tag %d ends at %d+%d - that\'s longer than the file (%d)'
42                 % (tag_code, pos, tag_len, len(content)))
43         yield (tag_code, content[pos:pos + tag_len])
44         pos += tag_len
45
46
47 class _AVMClass_Object(object):
48     def __init__(self, avm_class):
49         self.avm_class = avm_class
50
51     def __repr__(self):
52         return '%s#%x' % (self.avm_class.name, id(self))
53
54
55 class _ScopeDict(dict):
56     def __init__(self, avm_class):
57         super(_ScopeDict, self).__init__()
58         self.avm_class = avm_class
59
60     def __repr__(self):
61         return '%s__Scope(%s)' % (
62             self.avm_class.name,
63             super(_ScopeDict, self).__repr__())
64
65
66 class _AVMClass(object):
67     def __init__(self, name_idx, name, static_properties=None):
68         self.name_idx = name_idx
69         self.name = name
70         self.method_names = {}
71         self.method_idxs = {}
72         self.methods = {}
73         self.method_pyfunctions = {}
74         self.static_properties = static_properties if static_properties else {}
75
76         self.variables = _ScopeDict(self)
77         self.constants = {}
78
79     def make_object(self):
80         return _AVMClass_Object(self)
81
82     def __repr__(self):
83         return '_AVMClass(%s)' % (self.name)
84
85     def register_methods(self, methods):
86         self.method_names.update(methods.items())
87         self.method_idxs.update(dict(
88             (idx, name)
89             for name, idx in methods.items()))
90
91
92 class _Multiname(object):
93     def __init__(self, kind):
94         self.kind = kind
95
96     def __repr__(self):
97         return '[MULTINAME kind: 0x%x]' % self.kind
98
99
100 def _read_int(reader):
101     res = 0
102     shift = 0
103     for _ in range(5):
104         buf = reader.read(1)
105         assert len(buf) == 1
106         b = compat_struct_unpack('<B', buf)[0]
107         res = res | ((b & 0x7f) << shift)
108         if b & 0x80 == 0:
109             break
110         shift += 7
111     return res
112
113
114 def _u30(reader):
115     res = _read_int(reader)
116     assert res & 0xf0000000 == 0
117     return res
118 _u32 = _read_int
119
120
121 def _s32(reader):
122     v = _read_int(reader)
123     if v & 0x80000000 != 0:
124         v = - ((v ^ 0xffffffff) + 1)
125     return v
126
127
128 def _s24(reader):
129     bs = reader.read(3)
130     assert len(bs) == 3
131     last_byte = b'\xff' if (ord(bs[2:3]) >= 0x80) else b'\x00'
132     return compat_struct_unpack('<i', bs + last_byte)[0]
133
134
135 def _read_string(reader):
136     slen = _u30(reader)
137     resb = reader.read(slen)
138     assert len(resb) == slen
139     return resb.decode('utf-8')
140
141
142 def _read_bytes(count, reader):
143     assert count >= 0
144     resb = reader.read(count)
145     assert len(resb) == count
146     return resb
147
148
149 def _read_byte(reader):
150     resb = _read_bytes(1, reader=reader)
151     res = compat_struct_unpack('<B', resb)[0]
152     return res
153
154
155 StringClass = _AVMClass('(no name idx)', 'String')
156 ByteArrayClass = _AVMClass('(no name idx)', 'ByteArray')
157 TimerClass = _AVMClass('(no name idx)', 'Timer')
158 TimerEventClass = _AVMClass('(no name idx)', 'TimerEvent', {'TIMER': 'timer'})
159 _builtin_classes = {
160     StringClass.name: StringClass,
161     ByteArrayClass.name: ByteArrayClass,
162     TimerClass.name: TimerClass,
163     TimerEventClass.name: TimerEventClass,
164 }
165
166
167 class _Undefined(object):
168     def __bool__(self):
169         return False
170     __nonzero__ = __bool__
171
172     def __hash__(self):
173         return 0
174
175     def __str__(self):
176         return 'undefined'
177     __repr__ = __str__
178
179 undefined = _Undefined()
180
181
182 class SWFInterpreter(object):
183     def __init__(self, file_contents):
184         self._patched_functions = {
185             (TimerClass, 'addEventListener'): lambda params: undefined,
186         }
187         code_tag = next(tag
188                         for tag_code, tag in _extract_tags(file_contents)
189                         if tag_code == 82)
190         p = code_tag.index(b'\0', 4) + 1
191         code_reader = io.BytesIO(code_tag[p:])
192
193         # Parse ABC (AVM2 ByteCode)
194
195         # Define a couple convenience methods
196         u30 = lambda *args: _u30(*args, reader=code_reader)
197         s32 = lambda *args: _s32(*args, reader=code_reader)
198         u32 = lambda *args: _u32(*args, reader=code_reader)
199         read_bytes = lambda *args: _read_bytes(*args, reader=code_reader)
200         read_byte = lambda *args: _read_byte(*args, reader=code_reader)
201
202         # minor_version + major_version
203         read_bytes(2 + 2)
204
205         # Constant pool
206         int_count = u30()
207         self.constant_ints = [0]
208         for _c in range(1, int_count):
209             self.constant_ints.append(s32())
210         self.constant_uints = [0]
211         uint_count = u30()
212         for _c in range(1, uint_count):
213             self.constant_uints.append(u32())
214         double_count = u30()
215         read_bytes(max(0, (double_count - 1)) * 8)
216         string_count = u30()
217         self.constant_strings = ['']
218         for _c in range(1, string_count):
219             s = _read_string(code_reader)
220             self.constant_strings.append(s)
221         namespace_count = u30()
222         for _c in range(1, namespace_count):
223             read_bytes(1)  # kind
224             u30()  # name
225         ns_set_count = u30()
226         for _c in range(1, ns_set_count):
227             count = u30()
228             for _c2 in range(count):
229                 u30()
230         multiname_count = u30()
231         MULTINAME_SIZES = {
232             0x07: 2,  # QName
233             0x0d: 2,  # QNameA
234             0x0f: 1,  # RTQName
235             0x10: 1,  # RTQNameA
236             0x11: 0,  # RTQNameL
237             0x12: 0,  # RTQNameLA
238             0x09: 2,  # Multiname
239             0x0e: 2,  # MultinameA
240             0x1b: 1,  # MultinameL
241             0x1c: 1,  # MultinameLA
242         }
243         self.multinames = ['']
244         for _c in range(1, multiname_count):
245             kind = u30()
246             assert kind in MULTINAME_SIZES, 'Invalid multiname kind %r' % kind
247             if kind == 0x07:
248                 u30()  # namespace_idx
249                 name_idx = u30()
250                 self.multinames.append(self.constant_strings[name_idx])
251             elif kind == 0x09:
252                 name_idx = u30()
253                 u30()
254                 self.multinames.append(self.constant_strings[name_idx])
255             else:
256                 self.multinames.append(_Multiname(kind))
257                 for _c2 in range(MULTINAME_SIZES[kind]):
258                     u30()
259
260         # Methods
261         method_count = u30()
262         MethodInfo = collections.namedtuple(
263             'MethodInfo',
264             ['NEED_ARGUMENTS', 'NEED_REST'])
265         method_infos = []
266         for method_id in range(method_count):
267             param_count = u30()
268             u30()  # return type
269             for _ in range(param_count):
270                 u30()  # param type
271             u30()  # name index (always 0 for youtube)
272             flags = read_byte()
273             if flags & 0x08 != 0:
274                 # Options present
275                 option_count = u30()
276                 for c in range(option_count):
277                     u30()  # val
278                     read_bytes(1)  # kind
279             if flags & 0x80 != 0:
280                 # Param names present
281                 for _ in range(param_count):
282                     u30()  # param name
283             mi = MethodInfo(flags & 0x01 != 0, flags & 0x04 != 0)
284             method_infos.append(mi)
285
286         # Metadata
287         metadata_count = u30()
288         for _c in range(metadata_count):
289             u30()  # name
290             item_count = u30()
291             for _c2 in range(item_count):
292                 u30()  # key
293                 u30()  # value
294
295         def parse_traits_info():
296             trait_name_idx = u30()
297             kind_full = read_byte()
298             kind = kind_full & 0x0f
299             attrs = kind_full >> 4
300             methods = {}
301             constants = None
302             if kind == 0x00:  # Slot
303                 u30()  # Slot id
304                 u30()  # type_name_idx
305                 vindex = u30()
306                 if vindex != 0:
307                     read_byte()  # vkind
308             elif kind == 0x06:  # Const
309                 u30()  # Slot id
310                 u30()  # type_name_idx
311                 vindex = u30()
312                 vkind = 'any'
313                 if vindex != 0:
314                     vkind = read_byte()
315                 if vkind == 0x03:  # Constant_Int
316                     value = self.constant_ints[vindex]
317                 elif vkind == 0x04:  # Constant_UInt
318                     value = self.constant_uints[vindex]
319                 else:
320                     return {}, None  # Ignore silently for now
321                 constants = {self.multinames[trait_name_idx]: value}
322             elif kind in (0x01, 0x02, 0x03):  # Method / Getter / Setter
323                 u30()  # disp_id
324                 method_idx = u30()
325                 methods[self.multinames[trait_name_idx]] = method_idx
326             elif kind == 0x04:  # Class
327                 u30()  # slot_id
328                 u30()  # classi
329             elif kind == 0x05:  # Function
330                 u30()  # slot_id
331                 function_idx = u30()
332                 methods[function_idx] = self.multinames[trait_name_idx]
333             else:
334                 raise ExtractorError('Unsupported trait kind %d' % kind)
335
336             if attrs & 0x4 != 0:  # Metadata present
337                 metadata_count = u30()
338                 for _c3 in range(metadata_count):
339                     u30()  # metadata index
340
341             return methods, constants
342
343         # Classes
344         class_count = u30()
345         classes = []
346         for class_id in range(class_count):
347             name_idx = u30()
348
349             cname = self.multinames[name_idx]
350             avm_class = _AVMClass(name_idx, cname)
351             classes.append(avm_class)
352
353             u30()  # super_name idx
354             flags = read_byte()
355             if flags & 0x08 != 0:  # Protected namespace is present
356                 u30()  # protected_ns_idx
357             intrf_count = u30()
358             for _c2 in range(intrf_count):
359                 u30()
360             u30()  # iinit
361             trait_count = u30()
362             for _c2 in range(trait_count):
363                 trait_methods, trait_constants = parse_traits_info()
364                 avm_class.register_methods(trait_methods)
365                 if trait_constants:
366                     avm_class.constants.update(trait_constants)
367
368         assert len(classes) == class_count
369         self._classes_by_name = dict((c.name, c) for c in classes)
370
371         for avm_class in classes:
372             avm_class.cinit_idx = u30()
373             trait_count = u30()
374             for _c2 in range(trait_count):
375                 trait_methods, trait_constants = parse_traits_info()
376                 avm_class.register_methods(trait_methods)
377                 if trait_constants:
378                     avm_class.constants.update(trait_constants)
379
380         # Scripts
381         script_count = u30()
382         for _c in range(script_count):
383             u30()  # init
384             trait_count = u30()
385             for _c2 in range(trait_count):
386                 parse_traits_info()
387
388         # Method bodies
389         method_body_count = u30()
390         Method = collections.namedtuple('Method', ['code', 'local_count'])
391         self._all_methods = []
392         for _c in range(method_body_count):
393             method_idx = u30()
394             u30()  # max_stack
395             local_count = u30()
396             u30()  # init_scope_depth
397             u30()  # max_scope_depth
398             code_length = u30()
399             code = read_bytes(code_length)
400             m = Method(code, local_count)
401             self._all_methods.append(m)
402             for avm_class in classes:
403                 if method_idx in avm_class.method_idxs:
404                     avm_class.methods[avm_class.method_idxs[method_idx]] = m
405             exception_count = u30()
406             for _c2 in range(exception_count):
407                 u30()  # from
408                 u30()  # to
409                 u30()  # target
410                 u30()  # exc_type
411                 u30()  # var_name
412             trait_count = u30()
413             for _c2 in range(trait_count):
414                 parse_traits_info()
415
416         assert p + code_reader.tell() == len(code_tag)
417
418     def patch_function(self, avm_class, func_name, f):
419         self._patched_functions[(avm_class, func_name)] = f
420
421     def extract_class(self, class_name, call_cinit=True):
422         try:
423             res = self._classes_by_name[class_name]
424         except KeyError:
425             raise ExtractorError('Class %r not found' % class_name)
426
427         if call_cinit and hasattr(res, 'cinit_idx'):
428             res.register_methods({'$cinit': res.cinit_idx})
429             res.methods['$cinit'] = self._all_methods[res.cinit_idx]
430             cinit = self.extract_function(res, '$cinit')
431             cinit([])
432
433         return res
434
435     def extract_function(self, avm_class, func_name):
436         p = self._patched_functions.get((avm_class, func_name))
437         if p:
438             return p
439         if func_name in avm_class.method_pyfunctions:
440             return avm_class.method_pyfunctions[func_name]
441         if func_name in self._classes_by_name:
442             return self._classes_by_name[func_name].make_object()
443         if func_name not in avm_class.methods:
444             raise ExtractorError('Cannot find function %s.%s' % (
445                 avm_class.name, func_name))
446         m = avm_class.methods[func_name]
447
448         def resfunc(args):
449             # Helper functions
450             coder = io.BytesIO(m.code)
451             s24 = lambda: _s24(coder)
452             u30 = lambda: _u30(coder)
453
454             registers = [avm_class.variables] + list(args) + [None] * m.local_count
455             stack = []
456             scopes = collections.deque([
457                 self._classes_by_name, avm_class.constants, avm_class.variables])
458             while True:
459                 opcode = _read_byte(coder)
460                 if opcode == 9:  # label
461                     pass  # Spec says: "Do nothing."
462                 elif opcode == 16:  # jump
463                     offset = s24()
464                     coder.seek(coder.tell() + offset)
465                 elif opcode == 17:  # iftrue
466                     offset = s24()
467                     value = stack.pop()
468                     if value:
469                         coder.seek(coder.tell() + offset)
470                 elif opcode == 18:  # iffalse
471                     offset = s24()
472                     value = stack.pop()
473                     if not value:
474                         coder.seek(coder.tell() + offset)
475                 elif opcode == 19:  # ifeq
476                     offset = s24()
477                     value2 = stack.pop()
478                     value1 = stack.pop()
479                     if value2 == value1:
480                         coder.seek(coder.tell() + offset)
481                 elif opcode == 20:  # ifne
482                     offset = s24()
483                     value2 = stack.pop()
484                     value1 = stack.pop()
485                     if value2 != value1:
486                         coder.seek(coder.tell() + offset)
487                 elif opcode == 21:  # iflt
488                     offset = s24()
489                     value2 = stack.pop()
490                     value1 = stack.pop()
491                     if value1 < value2:
492                         coder.seek(coder.tell() + offset)
493                 elif opcode == 32:  # pushnull
494                     stack.append(None)
495                 elif opcode == 33:  # pushundefined
496                     stack.append(undefined)
497                 elif opcode == 36:  # pushbyte
498                     v = _read_byte(coder)
499                     stack.append(v)
500                 elif opcode == 37:  # pushshort
501                     v = u30()
502                     stack.append(v)
503                 elif opcode == 38:  # pushtrue
504                     stack.append(True)
505                 elif opcode == 39:  # pushfalse
506                     stack.append(False)
507                 elif opcode == 40:  # pushnan
508                     stack.append(float('NaN'))
509                 elif opcode == 42:  # dup
510                     value = stack[-1]
511                     stack.append(value)
512                 elif opcode == 44:  # pushstring
513                     idx = u30()
514                     stack.append(self.constant_strings[idx])
515                 elif opcode == 48:  # pushscope
516                     new_scope = stack.pop()
517                     scopes.append(new_scope)
518                 elif opcode == 66:  # construct
519                     arg_count = u30()
520                     args = list(reversed(
521                         [stack.pop() for _ in range(arg_count)]))
522                     obj = stack.pop()
523                     res = obj.avm_class.make_object()
524                     stack.append(res)
525                 elif opcode == 70:  # callproperty
526                     index = u30()
527                     mname = self.multinames[index]
528                     arg_count = u30()
529                     args = list(reversed(
530                         [stack.pop() for _ in range(arg_count)]))
531                     obj = stack.pop()
532
533                     if obj == StringClass:
534                         if mname == 'String':
535                             assert len(args) == 1
536                             assert isinstance(args[0], (
537                                 int, compat_str, _Undefined))
538                             if args[0] == undefined:
539                                 res = 'undefined'
540                             else:
541                                 res = compat_str(args[0])
542                             stack.append(res)
543                             continue
544                         else:
545                             raise NotImplementedError(
546                                 'Function String.%s is not yet implemented'
547                                 % mname)
548                     elif isinstance(obj, _AVMClass_Object):
549                         func = self.extract_function(obj.avm_class, mname)
550                         res = func(args)
551                         stack.append(res)
552                         continue
553                     elif isinstance(obj, _AVMClass):
554                         func = self.extract_function(obj, mname)
555                         res = func(args)
556                         stack.append(res)
557                         continue
558                     elif isinstance(obj, _ScopeDict):
559                         if mname in obj.avm_class.method_names:
560                             func = self.extract_function(obj.avm_class, mname)
561                             res = func(args)
562                         else:
563                             res = obj[mname]
564                         stack.append(res)
565                         continue
566                     elif isinstance(obj, compat_str):
567                         if mname == 'split':
568                             assert len(args) == 1
569                             assert isinstance(args[0], compat_str)
570                             if args[0] == '':
571                                 res = list(obj)
572                             else:
573                                 res = obj.split(args[0])
574                             stack.append(res)
575                             continue
576                         elif mname == 'charCodeAt':
577                             assert len(args) <= 1
578                             idx = 0 if len(args) == 0 else args[0]
579                             assert isinstance(idx, int)
580                             res = ord(obj[idx])
581                             stack.append(res)
582                             continue
583                     elif isinstance(obj, list):
584                         if mname == 'slice':
585                             assert len(args) == 1
586                             assert isinstance(args[0], int)
587                             res = obj[args[0]:]
588                             stack.append(res)
589                             continue
590                         elif mname == 'join':
591                             assert len(args) == 1
592                             assert isinstance(args[0], compat_str)
593                             res = args[0].join(obj)
594                             stack.append(res)
595                             continue
596                     raise NotImplementedError(
597                         'Unsupported property %r on %r'
598                         % (mname, obj))
599                 elif opcode == 71:  # returnvoid
600                     res = undefined
601                     return res
602                 elif opcode == 72:  # returnvalue
603                     res = stack.pop()
604                     return res
605                 elif opcode == 73:  # constructsuper
606                     # Not yet implemented, just hope it works without it
607                     arg_count = u30()
608                     args = list(reversed(
609                         [stack.pop() for _ in range(arg_count)]))
610                     obj = stack.pop()
611                 elif opcode == 74:  # constructproperty
612                     index = u30()
613                     arg_count = u30()
614                     args = list(reversed(
615                         [stack.pop() for _ in range(arg_count)]))
616                     obj = stack.pop()
617
618                     mname = self.multinames[index]
619                     assert isinstance(obj, _AVMClass)
620
621                     # We do not actually call the constructor for now;
622                     # we just pretend it does nothing
623                     stack.append(obj.make_object())
624                 elif opcode == 79:  # callpropvoid
625                     index = u30()
626                     mname = self.multinames[index]
627                     arg_count = u30()
628                     args = list(reversed(
629                         [stack.pop() for _ in range(arg_count)]))
630                     obj = stack.pop()
631                     if isinstance(obj, _AVMClass_Object):
632                         func = self.extract_function(obj.avm_class, mname)
633                         res = func(args)
634                         assert res is undefined
635                         continue
636                     if isinstance(obj, _ScopeDict):
637                         assert mname in obj.avm_class.method_names
638                         func = self.extract_function(obj.avm_class, mname)
639                         res = func(args)
640                         assert res is undefined
641                         continue
642                     if mname == 'reverse':
643                         assert isinstance(obj, list)
644                         obj.reverse()
645                     else:
646                         raise NotImplementedError(
647                             'Unsupported (void) property %r on %r'
648                             % (mname, obj))
649                 elif opcode == 86:  # newarray
650                     arg_count = u30()
651                     arr = []
652                     for i in range(arg_count):
653                         arr.append(stack.pop())
654                     arr = arr[::-1]
655                     stack.append(arr)
656                 elif opcode == 93:  # findpropstrict
657                     index = u30()
658                     mname = self.multinames[index]
659                     for s in reversed(scopes):
660                         if mname in s:
661                             res = s
662                             break
663                     else:
664                         res = scopes[0]
665                     if mname not in res and mname in _builtin_classes:
666                         stack.append(_builtin_classes[mname])
667                     else:
668                         stack.append(res[mname])
669                 elif opcode == 94:  # findproperty
670                     index = u30()
671                     mname = self.multinames[index]
672                     for s in reversed(scopes):
673                         if mname in s:
674                             res = s
675                             break
676                     else:
677                         res = avm_class.variables
678                     stack.append(res)
679                 elif opcode == 96:  # getlex
680                     index = u30()
681                     mname = self.multinames[index]
682                     for s in reversed(scopes):
683                         if mname in s:
684                             scope = s
685                             break
686                     else:
687                         scope = avm_class.variables
688
689                     if mname in scope:
690                         res = scope[mname]
691                     elif mname in _builtin_classes:
692                         res = _builtin_classes[mname]
693                     else:
694                         # Assume uninitialized
695                         # TODO warn here
696                         res = undefined
697                     stack.append(res)
698                 elif opcode == 97:  # setproperty
699                     index = u30()
700                     value = stack.pop()
701                     idx = self.multinames[index]
702                     if isinstance(idx, _Multiname):
703                         idx = stack.pop()
704                     obj = stack.pop()
705                     obj[idx] = value
706                 elif opcode == 98:  # getlocal
707                     index = u30()
708                     stack.append(registers[index])
709                 elif opcode == 99:  # setlocal
710                     index = u30()
711                     value = stack.pop()
712                     registers[index] = value
713                 elif opcode == 102:  # getproperty
714                     index = u30()
715                     pname = self.multinames[index]
716                     if pname == 'length':
717                         obj = stack.pop()
718                         assert isinstance(obj, (compat_str, list))
719                         stack.append(len(obj))
720                     elif isinstance(pname, compat_str):  # Member access
721                         obj = stack.pop()
722                         if isinstance(obj, _AVMClass):
723                             res = obj.static_properties[pname]
724                             stack.append(res)
725                             continue
726
727                         assert isinstance(obj, (dict, _ScopeDict)),\
728                             'Accessing member %r on %r' % (pname, obj)
729                         res = obj.get(pname, undefined)
730                         stack.append(res)
731                     else:  # Assume attribute access
732                         idx = stack.pop()
733                         assert isinstance(idx, int)
734                         obj = stack.pop()
735                         assert isinstance(obj, list)
736                         stack.append(obj[idx])
737                 elif opcode == 104:  # initproperty
738                     index = u30()
739                     value = stack.pop()
740                     idx = self.multinames[index]
741                     if isinstance(idx, _Multiname):
742                         idx = stack.pop()
743                     obj = stack.pop()
744                     obj[idx] = value
745                 elif opcode == 115:  # convert_
746                     value = stack.pop()
747                     intvalue = int(value)
748                     stack.append(intvalue)
749                 elif opcode == 128:  # coerce
750                     u30()
751                 elif opcode == 130:  # coerce_a
752                     value = stack.pop()
753                     # um, yes, it's any value
754                     stack.append(value)
755                 elif opcode == 133:  # coerce_s
756                     assert isinstance(stack[-1], (type(None), compat_str))
757                 elif opcode == 147:  # decrement
758                     value = stack.pop()
759                     assert isinstance(value, int)
760                     stack.append(value - 1)
761                 elif opcode == 149:  # typeof
762                     value = stack.pop()
763                     return {
764                         _Undefined: 'undefined',
765                         compat_str: 'String',
766                         int: 'Number',
767                         float: 'Number',
768                     }[type(value)]
769                 elif opcode == 160:  # add
770                     value2 = stack.pop()
771                     value1 = stack.pop()
772                     res = value1 + value2
773                     stack.append(res)
774                 elif opcode == 161:  # subtract
775                     value2 = stack.pop()
776                     value1 = stack.pop()
777                     res = value1 - value2
778                     stack.append(res)
779                 elif opcode == 162:  # multiply
780                     value2 = stack.pop()
781                     value1 = stack.pop()
782                     res = value1 * value2
783                     stack.append(res)
784                 elif opcode == 164:  # modulo
785                     value2 = stack.pop()
786                     value1 = stack.pop()
787                     res = value1 % value2
788                     stack.append(res)
789                 elif opcode == 168:  # bitand
790                     value2 = stack.pop()
791                     value1 = stack.pop()
792                     assert isinstance(value1, int)
793                     assert isinstance(value2, int)
794                     res = value1 & value2
795                     stack.append(res)
796                 elif opcode == 171:  # equals
797                     value2 = stack.pop()
798                     value1 = stack.pop()
799                     result = value1 == value2
800                     stack.append(result)
801                 elif opcode == 175:  # greaterequals
802                     value2 = stack.pop()
803                     value1 = stack.pop()
804                     result = value1 >= value2
805                     stack.append(result)
806                 elif opcode == 192:  # increment_i
807                     value = stack.pop()
808                     assert isinstance(value, int)
809                     stack.append(value + 1)
810                 elif opcode == 208:  # getlocal_0
811                     stack.append(registers[0])
812                 elif opcode == 209:  # getlocal_1
813                     stack.append(registers[1])
814                 elif opcode == 210:  # getlocal_2
815                     stack.append(registers[2])
816                 elif opcode == 211:  # getlocal_3
817                     stack.append(registers[3])
818                 elif opcode == 212:  # setlocal_0
819                     registers[0] = stack.pop()
820                 elif opcode == 213:  # setlocal_1
821                     registers[1] = stack.pop()
822                 elif opcode == 214:  # setlocal_2
823                     registers[2] = stack.pop()
824                 elif opcode == 215:  # setlocal_3
825                     registers[3] = stack.pop()
826                 else:
827                     raise NotImplementedError(
828                         'Unsupported opcode %d' % opcode)
829
830         avm_class.method_pyfunctions[func_name] = resfunc
831         return resfunc