def __init__(self, name):
construct.Struct.__init__(
self, name, construct.Bytes('header', 8),
construct.Value(
'total_bytes',
lambda ctx: self.__total_utf8_bytes__(ctx['header'])),
construct.MetaRepeater(
lambda ctx: self.__total_utf8_bytes__(ctx['header']) - 1,
construct.Bytes('sub_byte', 8)),
construct.Value('value',
lambda ctx: self.__calculate_utf8_value__(ctx)))
construct.Anchor('stream_end'))
VAULT_ATTRIBUTE_EXTRA = construct.Struct('VAULT_ATTRIBUTE_EXTRA',
construct.ULInt32('id'),
construct.ULInt32('attr_unknown_1'),
construct.ULInt32('attr_unknown_2'),
construct.Embed(SIZED_DATA))
VAULT_ATTRIBUTE_MAP_ENTRY = construct.Struct(
'VAULT_ATTRIBUTE_MAP_ENTRY', construct.ULInt32('id'),
construct.ULInt32('offset'), construct.ULInt32('attr_map_entry_unknown_1'),
construct.Pointer(lambda ctx: ctx.offset, VAULT_ATTRIBUTE))
VAULT_VCRD = construct.Struct(
'VAULT_VCRD', GUID('schema_guid'), construct.ULInt32('vcrd_unknown_1'),
FILETIME('last_update'), construct.ULInt32('vcrd_unknown_2'),
construct.ULInt32('vcrd_unknown_3'),
construct.Rename('description', UNICODE_STRING),
construct.ULInt32('attributes_array_size'),
construct.Value(
'attributes_num', lambda ctx:
(ctx.attributes_array_size / VAULT_ATTRIBUTE_MAP_ENTRY.sizeof())),
construct.Rename(
'attributes',
construct.Array(lambda ctx: ctx.attributes_num,
VAULT_ATTRIBUTE_MAP_ENTRY)),
construct.Pointer(
lambda ctx:
(ctx.attributes[ctx.attributes_num - 1].VAULT_ATTRIBUTE.stream_end),
construct.Rename('extra_entry', VAULT_ATTRIBUTE_EXTRA)))
# from comment string, build Containers
encoder=lambda obj, ctx: construct.Container(blocks=[
construct.Container(
block_size=len(chunk),
data_values=chunk,
) for chunk in [obj[i:i + 255] for i in xrange(0, len(obj), 255)]
] + [construct.Container(block_size=0, data_values='')], ),
# from Containers, build comment string
decoder=lambda obj, ctx: ''.join(dsb.data_values
for dsb in obj.blocks),
)
_image_block = construct.Struct(
'image',
construct.Value('block_type', lambda ctx: 'image'),
construct.Struct(
'image_descriptor',
construct.ULInt16('left'),
construct.ULInt16('top'),
construct.ULInt16('width'),
construct.ULInt16('height'),
construct.EmbeddedBitStruct(
construct.Flag('lct_flag'),
construct.Flag('interlace_flag'),
construct.Flag('sort_flag'),
construct.Padding(2), # reserved
construct.macros.BitField('lct_size', 3),
),
),
construct.If(
AXSString = construct.Struct("AXSString", construct.ULInt32("length"),
construct.Bytes("data", lambda ctx: ctx.length))
AXSKeyEntry = construct.Struct("AXSKeyEntry", construct.Array(2, AXSString),
construct.ULInt32("unk"))
AXSKeyMan = construct.Struct(
"AXSKeyMan",
construct.ULInt32("nb_entry"),
#construct.Array(lambda ctx: ctx.nb_entry, AXSKeyEntry))
construct.Array(1, AXSKeyEntry))
binInfo = construct.Struct(
"binInfo", construct.ULInt16("a"), construct.ULInt8("b"),
construct.Value("type", lambda ctx: (ctx["b"] << 16) | ctx["a"]),
construct.ULInt32("size"), construct.ULInt32("unk_dword_00"),
construct.ULInt8("unk_byte_00"), construct.ULInt32("type_compression"),
construct.ULInt32("length"), construct.Bytes("data",
lambda ctx: ctx.length))
binInfoNext = construct.Struct("binInfoNext", construct.ULInt16("type"),
construct.ULInt32("size"),
construct.ULInt32("length"),
construct.Bytes("data", lambda ctx: ctx.length))
class Buffer:
def __init__(self, buf):
self.buf = buf
self.length = len(self.buf)
class FlacReader:
FRAME_HEADER = construct.Struct(
'frame_header', construct.Bits('sync', 14),
construct.Bits('reserved', 2), construct.Bits('block_size', 4),
construct.Bits('sample_rate', 4),
construct.Bits('channel_assignment', 4),
construct.Bits('bits_per_sample', 3), construct.Padding(1),
construct.IfThenElse(
'total_channels', lambda ctx1: ctx1['channel_assignment'] <= 7,
construct.Value('c', lambda ctx2: ctx2['channel_assignment'] + 1),
construct.Value('c', lambda ctx3: 2)), UTF8('frame_number'),
construct.IfThenElse(
'extended_block_size', lambda ctx1: ctx1['block_size'] == 6,
construct.Bits('b', 8),
construct.If(lambda ctx2: ctx2['block_size'] == 7,
construct.Bits('b', 16))),
construct.IfThenElse(
'extended_sample_rate', lambda ctx1: ctx1['sample_rate'] == 12,
construct.Bits('s', 8),
construct.If(lambda ctx2: ctx2['sample_rate'] in (13, 14),
construct.Bits('s', 16))), construct.Bits('crc8', 8))
UNARY = construct.Struct(
'unary',
construct.RepeatUntil(lambda obj, ctx: obj == '\x01',
construct.Field('bytes', 1)),
construct.Value('value', lambda ctx: len(ctx['bytes']) - 1))
SUBFRAME_HEADER = construct.Struct(
'subframe_header', construct.Padding(1),
construct.Bits('subframe_type', 6),
construct.Flag('has_wasted_bits_per_sample'),
construct.IfThenElse('wasted_bits_per_sample',
lambda ctx: ctx['has_wasted_bits_per_sample'],
PlusOne(Unary('value')),
construct.Value('value', lambda ctx2: 0)))
GET_BLOCKSIZE_FROM_STREAMINFO = -1
GET_8BIT_BLOCKSIZE_FROM_END_OF_HEADER = -2
GET_16BIT_BLOCKSIZE_FROM_END_OF_HEADER = -3
BLOCK_SIZE = (GET_BLOCKSIZE_FROM_STREAMINFO, 192, 576, 1152, 2304, 4608,
GET_8BIT_BLOCKSIZE_FROM_END_OF_HEADER,
GET_16BIT_BLOCKSIZE_FROM_END_OF_HEADER, 256, 512, 1024, 2048,
4096, 8192, 16384, 32768)
GET_SAMPLE_SIZE_FROM_STREAMINFO = -1
SAMPLE_SIZE = (GET_SAMPLE_SIZE_FROM_STREAMINFO, 8, 12, None, 16, 20, 24,
None)
def FIXED0(subframe, residual, i):
subframe.insert(i, residual[i])
def FIXED1(subframe, residual, i):
subframe.insert(i, subframe[i - 1] + residual[i])
def FIXED2(subframe, residual, i):
subframe.insert(i,
((2 * subframe[i - 1]) - subframe[i - 2] + \
residual[i]))
def FIXED3(subframe, residual, i):
subframe.insert(i,
((3 * subframe[i - 1]) - (3 * subframe[i - 2]) + \
subframe[i - 3] + residual[i]))
def FIXED4(subframe, residual, i):
subframe.insert(i,
((4 * subframe[i - 1]) - (6 * subframe[i - 2]) + \
(4 * subframe[i - 3]) - subframe[i - 4] + residual[i]))
#iterates over all of the channels, in order
def MERGE_INDEPENDENT(channel_list):
channel_data = [iter(c) for c in channel_list]
while (True):
for channel in channel_data:
yield channel.next()
def MERGE_LEFT(channel_list):
channel_left = iter(channel_list[0])
channel_side = iter(channel_list[1])
while (True):
left = channel_left.next()
side = channel_side.next()
yield left
yield left - side
def MERGE_RIGHT(channel_list):
channel_side = iter(channel_list[0])
channel_right = iter(channel_list[1])
while (True):
side = channel_side.next()
right = channel_right.next()
yield side + right
yield right
def MERGE_MID(channel_list):
channel_mid = iter(channel_list[0])
channel_side = iter(channel_list[1])
while (True):
mid = channel_mid.next()
side = channel_side.next()
mid = mid << 1
mid |= (side & 0x1)
yield (mid + side) >> 1
yield (mid - side) >> 1
CHANNEL_FUNCTIONS = (MERGE_INDEPENDENT, MERGE_INDEPENDENT,
MERGE_INDEPENDENT, MERGE_INDEPENDENT,
MERGE_INDEPENDENT, MERGE_INDEPENDENT,
MERGE_INDEPENDENT, MERGE_INDEPENDENT, MERGE_LEFT,
MERGE_RIGHT, MERGE_MID)
FIXED_FUNCTIONS = (FIXED0, FIXED1, FIXED2, FIXED3, FIXED4)
def __init__(self, flac_stream):
self.stream = BufferedStream(flac_stream)
self.streaminfo = None
self.bitstream = None
#ensure the file starts with 'fLaC'
self.read_stream_marker()
#initialize self.bitstream
self.begin_bitstream()
#find self.streaminfo in case we need it
self.read_metadata_blocks()
def close(self):
if (self.bitstream != None):
self.bitstream.close()
else:
self.stream.close()
def read_stream_marker(self):
if (self.stream.read(4) != 'fLaC'):
raise FlacStreamException('invalid stream marker')
def read_metadata_blocks(self):
block = audiotools.FlacAudio.METADATA_BLOCK_HEADER.parse_stream(
self.stream)
while (block.last_block == 0):
if (block.block_type == 0):
self.streaminfo = audiotools.FlacAudio.STREAMINFO.parse_stream(
self.stream)
else:
self.stream.seek(block.block_length, 1)
block = audiotools.FlacAudio.METADATA_BLOCK_HEADER.parse_stream(
self.stream)
self.stream.seek(block.block_length, 1)
def begin_bitstream(self):
import bitstream
#self.bitstream = construct.BitStreamReader(self.stream)
self.bitstream = bitstream.BitStreamReader(self.stream)
def read_frame(self):
self.stream.reset_buffer()
try:
header = FlacReader.FRAME_HEADER.parse_stream(self.bitstream)
except construct.core.FieldError:
return ""
if (header.sync != 0x3FFE):
raise FlacStreamException('invalid sync')
if (crc8(self.stream.getvalue()[0:-1]) != header.crc8):
raise FlacStreamException('crc8 checksum failed')
#block_size tells us how many samples we need from each subframe
block_size = FlacReader.BLOCK_SIZE[header.block_size]
if (block_size == self.GET_BLOCKSIZE_FROM_STREAMINFO):
block_size = self.streaminfo.maximum_blocksize
elif ((block_size == self.GET_8BIT_BLOCKSIZE_FROM_END_OF_HEADER)
or (block_size == self.GET_16BIT_BLOCKSIZE_FROM_END_OF_HEADER)):
block_size = header.extended_block_size + 1
#grab subframe data as 32-bit array objects
subframe_data = []
for channel_number in xrange(header.total_channels):
subframe_data.append(
self.read_subframe(header, block_size, channel_number))
crc16sum = crc16(self.stream.getvalue())
#try to byte-align the stream
if (len(self.bitstream.buffer) > 0):
self.bitstream.read(len(self.bitstream.buffer))
if (crc16sum != construct.Bits('crc16', 16).parse_stream(
self.bitstream)):
raise FlacStreamException('crc16 checksum failed')
#convert our list of subframe data arrays into
#a string of sample data
if (FlacReader.SAMPLE_SIZE[header.bits_per_sample] == 16):
merged_frames = array.array(
'h', FlacReader.CHANNEL_FUNCTIONS[header.channel_assignment](
subframe_data))
if (audiotools.BIG_ENDIAN):
merged_frames.byteswap()
return merged_frames.tostring()
elif (FlacReader.SAMPLE_SIZE[header.bits_per_sample] == 8):
merged_frames = array.array(
'b', FlacReader.CHANNEL_FUNCTIONS[header.channel_assignment](
subframe_data))
return merged_frames.tostring()
else:
if (FlacReader.SAMPLE_SIZE[header.bits_per_sample] == \
self.GET_SAMPLE_SIZE_FROM_STREAMINFO):
bits_per_sample = self.streaminfo.bits_per_sample + 1
elif (FlacReader.SAMPLE_SIZE[header.bits_per_sample] == None):
raise FlacStreamException('invalid bits per sample')
else:
bits_per_sample = FlacReader.SAMPLE_SIZE[
header.bits_per_sample]
stream = construct.GreedyRepeater(
construct.BitStruct(
'bits',
construct.Bits('value',
bits_per_sample,
swapped=True,
signed=True)))
return stream.build([
construct.Container(value=v)
for v in FlacReader.CHANNEL_FUNCTIONS[
header.channel_assignment](subframe_data)
])
def read_subframe(self, frame_header, block_size, channel_number):
subframe_header = \
FlacReader.SUBFRAME_HEADER.parse_stream(self.bitstream)
#figure out the bits-per-sample of this subframe
if ((frame_header.channel_assignment == 8) and (channel_number == 1)):
#if channel is stored as left+difference
#and this is the difference, add 1 bit
bits_per_sample = FlacReader.SAMPLE_SIZE[
frame_header.bits_per_sample] + 1
elif ((frame_header.channel_assignment == 9)
and (channel_number == 0)):
#if channel is stored as difference+right
#and this is the difference, add 1 bit
bits_per_sample = FlacReader.SAMPLE_SIZE[
frame_header.bits_per_sample] + 1
elif ((frame_header.channel_assignment == 10)
and (channel_number == 1)):
#if channel is stored as average+difference
#and this is the difference, add 1 bit
bits_per_sample = FlacReader.SAMPLE_SIZE[
frame_header.bits_per_sample] + 1
else:
#otherwise, use the number from the frame header
bits_per_sample = FlacReader.SAMPLE_SIZE[
frame_header.bits_per_sample]
if (subframe_header.has_wasted_bits_per_sample):
bits_per_sample -= subframe_header.wasted_bits_per_sample
if (subframe_header.subframe_type == 0):
subframe = self.read_subframe_constant(block_size, bits_per_sample)
elif (subframe_header.subframe_type == 1):
subframe = self.read_subframe_verbatim(block_size, bits_per_sample)
elif ((subframe_header.subframe_type & 0x38) == 0x08):
subframe = self.read_subframe_fixed(
subframe_header.subframe_type & 0x07, block_size,
bits_per_sample)
elif ((subframe_header.subframe_type & 0x20) == 0x20):
subframe = self.read_subframe_lpc(
(subframe_header.subframe_type & 0x1F) + 1, block_size,
bits_per_sample)
else:
raise FlacStreamException('invalid subframe type')
if (subframe_header.has_wasted_bits_per_sample):
return array.array('i', [
i << subframe_header.wasted_bits_per_sample for i in subframe
])
else:
return subframe
def read_subframe_constant(self, block_size, bits_per_sample):
sample = construct.Bits('b',
bits_per_sample).parse_stream(self.bitstream)
subframe = array.array('i', [sample] * block_size)
return subframe
def read_subframe_verbatim(self, block_size, bits_per_sample):
return array.array(
'i',
construct.StrictRepeater(
block_size,
construct.Bits("samples", bits_per_sample,
signed=True)).parse_stream(self.bitstream))
def read_subframe_fixed(self, order, block_size, bits_per_sample):
samples = construct.StrictRepeater(
order,
construct.Bits("warm_up_samples", bits_per_sample, signed=True))
subframe = array.array('i', samples.parse_stream(self.bitstream))
residual = self.read_residual(block_size, order)
fixed_func = self.FIXED_FUNCTIONS[order]
for i in xrange(len(subframe), block_size):
fixed_func(subframe, residual, i)
return subframe
def read_subframe_lpc(self, order, block_size, bits_per_sample):
samples = construct.StrictRepeater(
order,
construct.Bits("warm_up_samples", bits_per_sample, signed=True))
subframe = array.array('i', samples.parse_stream(self.bitstream))
lpc_precision = construct.Bits('lpc_precision', 4).parse_stream(
self.bitstream) + 1
lpc_shift = construct.Bits('lpc_shift', 5).parse_stream(self.bitstream)
coefficients = array.array(
'i',
construct.StrictRepeater(
order,
construct.Bits('coefficients', lpc_precision,
signed=True)).parse_stream(self.bitstream))
residual = self.read_residual(block_size, order)
for i in xrange(len(subframe), block_size):
subframe.insert(i,
(sum(
[coefficients[j] * subframe[i - j - 1] for j in
xrange(0,len(coefficients))]) >> lpc_shift) + \
residual[i])
return subframe
def read_residual(self, block_size, predictor_order):
rice = array.array('i')
#add some dummy rice so that the Rice index matches
#that of the rest of the subframe
for i in xrange(predictor_order):
rice.append(0)
coding_method = self.bitstream.read(2)
if (coding_method == '\x00\x00'):
rice2 = False
elif (coding_method == '\x00\x01'):
rice2 = True
else:
raise FlacStreamException('invalid residual coding method')
partition_order = construct.Bits('partition_order',
4).parse_stream(self.bitstream)
if (partition_order > 0):
total_samples = ((block_size / 2**partition_order) -
predictor_order)
rice.extend(self.read_encoded_rice(total_samples, rice2))
for i in xrange(1, 2**partition_order):
total_samples = (block_size / 2**partition_order)
rice.extend(self.read_encoded_rice(total_samples, rice2))
else:
rice.extend(
self.read_encoded_rice(block_size - predictor_order, rice2))
return rice
def read_encoded_rice(self, total_samples, rice2=False):
bin_to_int = construct.lib.binary.bin_to_int
samples = array.array('i')
if (not rice2):
rice_parameter = construct.Bits('rice_parameter',
4).parse_stream(self.bitstream)
else:
rice_parameter = construct.Bits('rice_parameter',
5).parse_stream(self.bitstream)
if (rice_parameter != 0xF):
#a Rice encoded residual
for x in xrange(total_samples):
#count the number of 0 bits before the next 1 bit
#(unary encoding)
#to find our most significant bits
msb = 0
s = self.bitstream.read(1)
while (s != '\x01'):
msb += 1
s = self.bitstream.read(1)
#grab the proper number of least significant bits
lsb = bin_to_int(self.bitstream.read(rice_parameter))
#combine msb and lsb to get the Rice-encoded value
value = (msb << rice_parameter) | lsb
if ((value & 0x1) == 0x1): #negative
samples.append(-(value >> 1) - 1)
else: #positive
samples.append(value >> 1)
else:
#unencoded residual
bits_per_sample = construct.Bits('escape_code',
5).parse_stream(self.bitstream)
sample = construct.Bits("sample", bits_per_sample, signed=True)
for x in xrange(total_samples):
samples.append(sample.parse_stream(self.bitstream))
return samples
def MakeRva(name):
return construct.Embed(construct.Struct('EmbeddedRva',
construct.ULInt32(name),
construct.Value('VA', lambda ctx: idaapi.get_imagebase() + ctx[name])
))