diff options
Diffstat (limited to 'youtube_dl/swfinterp.py')
| -rw-r--r-- | youtube_dl/swfinterp.py | 56 |
1 files changed, 39 insertions, 17 deletions
diff --git a/youtube_dl/swfinterp.py b/youtube_dl/swfinterp.py index 1cd292138..49fade364 100644 --- a/youtube_dl/swfinterp.py +++ b/youtube_dl/swfinterp.py @@ -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() |