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[swfinterp] Start working on basic tests

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This commit is contained in:
Philipp Hagemeister 2014-07-18 14:20:34 +02:00
parent 5425626790
commit 0cb2056304
4 changed files with 126 additions and 17 deletions
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56
youtube_dl/swfinterp.py
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@ -8,8 +8,22 @@ import zlib
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
@ -18,7 +32,9 @@ def _extract_tags(content):
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
@ -88,8 +104,7 @@ def _read_string(reader):
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
@ -103,18 +118,8 @@ def _read_byte(reader):
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:])
@ -139,7 +144,7 @@ class SWFInterpreter(object):
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):
@ -349,6 +354,9 @@ class SWFInterpreter(object):
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])
@ -468,10 +476,24 @@ class SWFInterpreter(object):
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()