mirror of
https://github.com/l1ving/youtube-dl
synced 2024-11-24 04:32:53 +08:00
610 lines
22 KiB
Python
610 lines
22 KiB
Python
from __future__ import unicode_literals
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import collections
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import io
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import zlib
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from .utils import (
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compat_str,
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ExtractorError,
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struct_unpack,
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)
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def _extract_tags(file_contents):
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if file_contents[1:3] != b'WS':
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raise ExtractorError(
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'Not an SWF file; header is %r' % file_contents[:3])
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if file_contents[:1] == b'C':
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content = zlib.decompress(file_contents[8:])
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else:
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raise NotImplementedError(
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'Unsupported compression format %r' %
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file_contents[:1])
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# Determine number of bits in framesize rectangle
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framesize_nbits = struct_unpack('!B', content[:1])[0] >> 3
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framesize_len = (5 + 4 * framesize_nbits + 7) // 8
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pos = framesize_len + 2 + 2
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while pos < len(content):
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header16 = struct_unpack('<H', content[pos:pos + 2])[0]
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pos += 2
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tag_code = header16 >> 6
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tag_len = header16 & 0x3f
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if tag_len == 0x3f:
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tag_len = struct_unpack('<I', content[pos:pos + 4])[0]
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pos += 4
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assert pos + tag_len <= len(content), \
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('Tag %d ends at %d+%d - that\'s longer than the file (%d)'
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% (tag_code, pos, tag_len, len(content)))
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yield (tag_code, content[pos:pos + tag_len])
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pos += tag_len
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class _AVMClass_Object(object):
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def __init__(self, avm_class):
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self.avm_class = avm_class
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def __repr__(self):
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return '%s#%x' % (self.avm_class.name, id(self))
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class _ScopeDict(dict):
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def __init__(self, avm_class):
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super(_ScopeDict, self).__init__()
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self.avm_class = avm_class
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def __repr__(self):
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return '%s__Scope(%s)' % (
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self.avm_class.name,
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super(_ScopeDict, self).__repr__())
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class _AVMClass(object):
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def __init__(self, name_idx, name):
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self.name_idx = name_idx
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self.name = name
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self.method_names = {}
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self.method_idxs = {}
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self.methods = {}
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self.method_pyfunctions = {}
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self.variables = _ScopeDict(self)
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def make_object(self):
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return _AVMClass_Object(self)
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def __repr__(self):
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return '_AVMClass(%s)' % (self.name)
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def register_methods(self, methods):
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self.method_names.update(methods.items())
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self.method_idxs.update(dict(
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(idx, name)
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for name, idx in methods.items()))
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class _Multiname(object):
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def __init__(self, kind):
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self.kind = kind
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def __repr__(self):
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return '[MULTINAME kind: 0x%x]' % self.kind
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def _read_int(reader):
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res = 0
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shift = 0
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for _ in range(5):
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buf = reader.read(1)
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assert len(buf) == 1
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b = struct_unpack('<B', buf)[0]
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res = res | ((b & 0x7f) << shift)
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if b & 0x80 == 0:
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break
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shift += 7
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return res
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def _u30(reader):
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res = _read_int(reader)
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assert res & 0xf0000000 == 0
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return res
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_u32 = _read_int
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def _s32(reader):
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v = _read_int(reader)
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if v & 0x80000000 != 0:
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v = - ((v ^ 0xffffffff) + 1)
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return v
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def _s24(reader):
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bs = reader.read(3)
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assert len(bs) == 3
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last_byte = b'\xff' if (ord(bs[2:3]) >= 0x80) else b'\x00'
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return struct_unpack('<i', bs + last_byte)[0]
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def _read_string(reader):
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slen = _u30(reader)
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resb = reader.read(slen)
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assert len(resb) == slen
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return resb.decode('utf-8')
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def _read_bytes(count, reader):
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assert count >= 0
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resb = reader.read(count)
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assert len(resb) == count
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return resb
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def _read_byte(reader):
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resb = _read_bytes(1, reader=reader)
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res = struct_unpack('<B', resb)[0]
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return res
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class SWFInterpreter(object):
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def __init__(self, file_contents):
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code_tag = next(tag
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for tag_code, tag in _extract_tags(file_contents)
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if tag_code == 82)
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p = code_tag.index(b'\0', 4) + 1
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code_reader = io.BytesIO(code_tag[p:])
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# Parse ABC (AVM2 ByteCode)
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# Define a couple convenience methods
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u30 = lambda *args: _u30(*args, reader=code_reader)
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s32 = lambda *args: _s32(*args, reader=code_reader)
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u32 = lambda *args: _u32(*args, reader=code_reader)
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read_bytes = lambda *args: _read_bytes(*args, reader=code_reader)
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read_byte = lambda *args: _read_byte(*args, reader=code_reader)
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# minor_version + major_version
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read_bytes(2 + 2)
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# Constant pool
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int_count = u30()
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for _c in range(1, int_count):
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s32()
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uint_count = u30()
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for _c in range(1, uint_count):
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u32()
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double_count = u30()
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read_bytes(max(0, (double_count - 1)) * 8)
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string_count = u30()
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self.constant_strings = ['']
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for _c in range(1, string_count):
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s = _read_string(code_reader)
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self.constant_strings.append(s)
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namespace_count = u30()
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for _c in range(1, namespace_count):
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read_bytes(1) # kind
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u30() # name
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ns_set_count = u30()
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for _c in range(1, ns_set_count):
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count = u30()
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for _c2 in range(count):
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u30()
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multiname_count = u30()
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MULTINAME_SIZES = {
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0x07: 2, # QName
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0x0d: 2, # QNameA
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0x0f: 1, # RTQName
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0x10: 1, # RTQNameA
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0x11: 0, # RTQNameL
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0x12: 0, # RTQNameLA
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0x09: 2, # Multiname
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0x0e: 2, # MultinameA
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0x1b: 1, # MultinameL
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0x1c: 1, # MultinameLA
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}
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self.multinames = ['']
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for _c in range(1, multiname_count):
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kind = u30()
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assert kind in MULTINAME_SIZES, 'Invalid multiname kind %r' % kind
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if kind == 0x07:
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u30() # namespace_idx
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name_idx = u30()
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self.multinames.append(self.constant_strings[name_idx])
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else:
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self.multinames.append(_Multiname(kind))
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for _c2 in range(MULTINAME_SIZES[kind]):
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u30()
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# Methods
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method_count = u30()
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MethodInfo = collections.namedtuple(
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'MethodInfo',
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['NEED_ARGUMENTS', 'NEED_REST'])
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method_infos = []
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for method_id in range(method_count):
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param_count = u30()
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u30() # return type
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for _ in range(param_count):
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u30() # param type
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u30() # name index (always 0 for youtube)
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flags = read_byte()
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if flags & 0x08 != 0:
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# Options present
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option_count = u30()
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for c in range(option_count):
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u30() # val
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read_bytes(1) # kind
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if flags & 0x80 != 0:
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# Param names present
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for _ in range(param_count):
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u30() # param name
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mi = MethodInfo(flags & 0x01 != 0, flags & 0x04 != 0)
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method_infos.append(mi)
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# Metadata
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metadata_count = u30()
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for _c in range(metadata_count):
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u30() # name
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item_count = u30()
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for _c2 in range(item_count):
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u30() # key
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u30() # value
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def parse_traits_info():
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trait_name_idx = u30()
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kind_full = read_byte()
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kind = kind_full & 0x0f
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attrs = kind_full >> 4
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methods = {}
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if kind in [0x00, 0x06]: # Slot or Const
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u30() # Slot id
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u30() # type_name_idx
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vindex = u30()
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if vindex != 0:
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read_byte() # vkind
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elif kind in [0x01, 0x02, 0x03]: # Method / Getter / Setter
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u30() # disp_id
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method_idx = u30()
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methods[self.multinames[trait_name_idx]] = method_idx
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elif kind == 0x04: # Class
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u30() # slot_id
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u30() # classi
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elif kind == 0x05: # Function
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u30() # slot_id
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function_idx = u30()
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methods[function_idx] = self.multinames[trait_name_idx]
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else:
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raise ExtractorError('Unsupported trait kind %d' % kind)
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if attrs & 0x4 != 0: # Metadata present
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metadata_count = u30()
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for _c3 in range(metadata_count):
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u30() # metadata index
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return methods
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# Classes
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class_count = u30()
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classes = []
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for class_id in range(class_count):
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name_idx = u30()
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cname = self.multinames[name_idx]
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avm_class = _AVMClass(name_idx, cname)
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classes.append(avm_class)
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u30() # super_name idx
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flags = read_byte()
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if flags & 0x08 != 0: # Protected namespace is present
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u30() # protected_ns_idx
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intrf_count = u30()
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for _c2 in range(intrf_count):
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u30()
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u30() # iinit
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trait_count = u30()
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for _c2 in range(trait_count):
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trait_methods = parse_traits_info()
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avm_class.register_methods(trait_methods)
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assert len(classes) == class_count
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self._classes_by_name = dict((c.name, c) for c in classes)
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for avm_class in classes:
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u30() # cinit
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trait_count = u30()
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for _c2 in range(trait_count):
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trait_methods = parse_traits_info()
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avm_class.register_methods(trait_methods)
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# Scripts
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script_count = u30()
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for _c in range(script_count):
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u30() # init
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trait_count = u30()
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for _c2 in range(trait_count):
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parse_traits_info()
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# Method bodies
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method_body_count = u30()
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Method = collections.namedtuple('Method', ['code', 'local_count'])
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for _c in range(method_body_count):
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method_idx = u30()
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u30() # max_stack
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local_count = u30()
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u30() # init_scope_depth
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u30() # max_scope_depth
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code_length = u30()
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code = read_bytes(code_length)
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for avm_class in classes:
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if method_idx in avm_class.method_idxs:
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m = Method(code, local_count)
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avm_class.methods[avm_class.method_idxs[method_idx]] = m
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exception_count = u30()
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for _c2 in range(exception_count):
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u30() # from
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u30() # to
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u30() # target
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u30() # exc_type
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u30() # var_name
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trait_count = u30()
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for _c2 in range(trait_count):
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parse_traits_info()
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assert p + code_reader.tell() == len(code_tag)
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def extract_class(self, class_name):
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try:
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return self._classes_by_name[class_name]
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except KeyError:
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raise ExtractorError('Class %r not found' % class_name)
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def extract_function(self, avm_class, func_name):
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if func_name in avm_class.method_pyfunctions:
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return avm_class.method_pyfunctions[func_name]
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if func_name in self._classes_by_name:
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return self._classes_by_name[func_name].make_object()
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if func_name not in avm_class.methods:
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raise ExtractorError('Cannot find function %s.%s' % (
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avm_class.name, func_name))
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m = avm_class.methods[func_name]
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def resfunc(args):
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# Helper functions
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coder = io.BytesIO(m.code)
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s24 = lambda: _s24(coder)
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u30 = lambda: _u30(coder)
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registers = [avm_class.variables] + list(args) + [None] * m.local_count
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stack = []
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scopes = collections.deque([
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self._classes_by_name, avm_class.variables])
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while True:
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opcode = _read_byte(coder)
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if opcode == 17: # iftrue
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offset = s24()
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value = stack.pop()
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if value:
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coder.seek(coder.tell() + offset)
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elif opcode == 18: # iffalse
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offset = s24()
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value = stack.pop()
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if not value:
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coder.seek(coder.tell() + offset)
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elif opcode == 36: # pushbyte
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v = _read_byte(coder)
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stack.append(v)
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elif opcode == 42: # dup
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value = stack[-1]
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stack.append(value)
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elif opcode == 44: # pushstring
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idx = u30()
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stack.append(self.constant_strings[idx])
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elif opcode == 48: # pushscope
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new_scope = stack.pop()
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scopes.append(new_scope)
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elif opcode == 66: # construct
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arg_count = u30()
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args = list(reversed(
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[stack.pop() for _ in range(arg_count)]))
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obj = stack.pop()
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res = obj.avm_class.make_object()
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stack.append(res)
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elif opcode == 70: # callproperty
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index = u30()
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mname = self.multinames[index]
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arg_count = u30()
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args = list(reversed(
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[stack.pop() for _ in range(arg_count)]))
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obj = stack.pop()
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if isinstance(obj, _AVMClass_Object):
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func = self.extract_function(obj.avm_class, mname)
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res = func(args)
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stack.append(res)
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continue
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elif isinstance(obj, _ScopeDict):
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if mname in obj.avm_class.method_names:
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func = self.extract_function(obj.avm_class, mname)
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res = func(args)
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else:
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res = obj[mname]
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stack.append(res)
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continue
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elif isinstance(obj, compat_str):
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if mname == 'split':
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assert len(args) == 1
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assert isinstance(args[0], compat_str)
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if args[0] == '':
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res = list(obj)
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else:
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res = obj.split(args[0])
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stack.append(res)
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continue
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elif isinstance(obj, list):
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if mname == 'slice':
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assert len(args) == 1
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assert isinstance(args[0], int)
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res = obj[args[0]:]
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stack.append(res)
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continue
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elif mname == 'join':
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assert len(args) == 1
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assert isinstance(args[0], compat_str)
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res = args[0].join(obj)
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stack.append(res)
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continue
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raise NotImplementedError(
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'Unsupported property %r on %r'
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% (mname, obj))
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elif opcode == 72: # returnvalue
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res = stack.pop()
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return res
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elif opcode == 74: # constructproperty
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index = u30()
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arg_count = u30()
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args = list(reversed(
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[stack.pop() for _ in range(arg_count)]))
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obj = stack.pop()
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mname = self.multinames[index]
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assert isinstance(obj, _AVMClass)
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# We do not actually call the constructor for now;
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# we just pretend it does nothing
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stack.append(obj.make_object())
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elif opcode == 79: # callpropvoid
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index = u30()
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mname = self.multinames[index]
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arg_count = u30()
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args = list(reversed(
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[stack.pop() for _ in range(arg_count)]))
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obj = stack.pop()
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if mname == 'reverse':
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assert isinstance(obj, list)
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obj.reverse()
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else:
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raise NotImplementedError(
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'Unsupported (void) property %r on %r'
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% (mname, obj))
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elif opcode == 86: # newarray
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arg_count = u30()
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arr = []
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for i in range(arg_count):
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arr.append(stack.pop())
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arr = arr[::-1]
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stack.append(arr)
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elif opcode == 93: # findpropstrict
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index = u30()
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mname = self.multinames[index]
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for s in reversed(scopes):
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if mname in s:
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res = s
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break
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else:
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res = scopes[0]
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stack.append(res[mname])
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elif opcode == 94: # findproperty
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index = u30()
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mname = self.multinames[index]
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for s in reversed(scopes):
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if mname in s:
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res = s
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break
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else:
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res = avm_class.variables
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stack.append(res)
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elif opcode == 96: # getlex
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index = u30()
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mname = self.multinames[index]
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for s in reversed(scopes):
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if mname in s:
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scope = s
|
|
break
|
|
else:
|
|
scope = avm_class.variables
|
|
# I cannot find where static variables are initialized
|
|
# so let's just return None
|
|
res = scope.get(mname)
|
|
stack.append(res)
|
|
elif opcode == 97: # setproperty
|
|
index = u30()
|
|
value = stack.pop()
|
|
idx = self.multinames[index]
|
|
if isinstance(idx, _Multiname):
|
|
idx = stack.pop()
|
|
obj = stack.pop()
|
|
obj[idx] = value
|
|
elif opcode == 98: # getlocal
|
|
index = u30()
|
|
stack.append(registers[index])
|
|
elif opcode == 99: # setlocal
|
|
index = u30()
|
|
value = stack.pop()
|
|
registers[index] = value
|
|
elif opcode == 102: # getproperty
|
|
index = u30()
|
|
pname = self.multinames[index]
|
|
if pname == 'length':
|
|
obj = stack.pop()
|
|
assert isinstance(obj, list)
|
|
stack.append(len(obj))
|
|
else: # Assume attribute access
|
|
idx = stack.pop()
|
|
assert isinstance(idx, int)
|
|
obj = stack.pop()
|
|
assert isinstance(obj, list)
|
|
stack.append(obj[idx])
|
|
elif opcode == 115: # convert_
|
|
value = stack.pop()
|
|
intvalue = int(value)
|
|
stack.append(intvalue)
|
|
elif opcode == 128: # coerce
|
|
u30()
|
|
elif opcode == 133: # coerce_s
|
|
assert isinstance(stack[-1], (type(None), compat_str))
|
|
elif opcode == 160: # add
|
|
value2 = stack.pop()
|
|
value1 = stack.pop()
|
|
res = value1 + value2
|
|
stack.append(res)
|
|
elif opcode == 161: # subtract
|
|
value2 = stack.pop()
|
|
value1 = stack.pop()
|
|
res = value1 - value2
|
|
stack.append(res)
|
|
elif opcode == 164: # modulo
|
|
value2 = stack.pop()
|
|
value1 = stack.pop()
|
|
res = value1 % value2
|
|
stack.append(res)
|
|
elif opcode == 175: # greaterequals
|
|
value2 = stack.pop()
|
|
value1 = stack.pop()
|
|
result = value1 >= value2
|
|
stack.append(result)
|
|
elif opcode == 208: # getlocal_0
|
|
stack.append(registers[0])
|
|
elif opcode == 209: # getlocal_1
|
|
stack.append(registers[1])
|
|
elif opcode == 210: # getlocal_2
|
|
stack.append(registers[2])
|
|
elif opcode == 211: # getlocal_3
|
|
stack.append(registers[3])
|
|
elif opcode == 212: # setlocal_0
|
|
registers[0] = stack.pop()
|
|
elif opcode == 213: # setlocal_1
|
|
registers[1] = stack.pop()
|
|
elif opcode == 214: # setlocal_2
|
|
registers[2] = stack.pop()
|
|
elif opcode == 215: # setlocal_3
|
|
registers[3] = stack.pop()
|
|
else:
|
|
raise NotImplementedError(
|
|
'Unsupported opcode %d' % opcode)
|
|
|
|
avm_class.method_pyfunctions[func_name] = resfunc
|
|
return resfunc
|
|
|