from .utils import ExtractorError
-def _extract_tags(content):
- pos = 0
+def _extract_tags(file_contents):
+ if file_contents[1:3] != b'WS':
+ raise ExtractorError(
+ 'Not an SWF file; header is %r' % file_contents[:3])
+ if file_contents[:1] == b'C':
+ content = zlib.decompress(file_contents[8:])
+ else:
+ raise NotImplementedError(
+ 'Unsupported compression format %r' %
+ file_contents[:1])
+
+ # Determine number of bits in framesize rectangle
+ framesize_nbits = struct.unpack('!B', content[:1])[0] >> 3
+ framesize_len = (5 + 4 * framesize_nbits + 7) // 8
+
+ pos = framesize_len + 2 + 2
while pos < len(content):
header16 = struct.unpack('<H', content[pos:pos + 2])[0]
pos += 2
if tag_len == 0x3f:
tag_len = struct.unpack('<I', content[pos:pos + 4])[0]
pos += 4
- assert pos + tag_len <= len(content)
+ assert pos + tag_len <= len(content), \
+ ('Tag %d ends at %d+%d - that\'s longer than the file (%d)'
+ % (tag_code, pos, tag_len, len(content)))
yield (tag_code, content[pos:pos + tag_len])
pos += tag_len
def _read_bytes(count, reader):
- if reader is None:
- reader = code_reader
+ assert count >= 0
resb = reader.read(count)
assert len(resb) == count
return resb
class SWFInterpreter(object):
def __init__(self, file_contents):
- if file_contents[1:3] != b'WS':
- raise ExtractorError(
- 'Not an SWF file; header is %r' % file_contents[:3])
- if file_contents[:1] == b'C':
- content = zlib.decompress(file_contents[8:])
- else:
- raise NotImplementedError(
- 'Unsupported compression format %r' %
- file_contents[:1])
-
code_tag = next(tag
- for tag_code, tag in _extract_tags(content)
+ for tag_code, tag in _extract_tags(file_contents)
if tag_code == 82)
p = code_tag.index(b'\0', 4) + 1
code_reader = io.BytesIO(code_tag[p:])
for _c in range(1, uint_count):
u32()
double_count = u30()
- read_bytes((double_count - 1) * 8)
+ read_bytes(max(0, (double_count - 1)) * 8)
string_count = u30()
constant_strings = ['']
for _c in range(1, string_count):
elif opcode == 36: # pushbyte
v = _read_byte(coder)
stack.append(v)
+ elif opcode == 42: # dup
+ value = stack[-1]
+ stack.append(value)
elif opcode == 44: # pushstring
idx = u30()
stack.append(constant_strings[idx])
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()