def __init__(self, parent, name, tree, description=""):
Field.__init__(self, parent, name, 0, description)
endian = self.parent.endian
stream = self.parent.stream
addr = self.absolute_address
value = 0
met_ff = False
while (self.size, value) not in tree:
if addr % 8 == 0:
last_byte = stream.readBytes(addr - 8, 1)
if last_byte == b'\xFF':
next_byte = stream.readBytes(addr, 1)
if next_byte != b'\x00':
raise FieldError("Unexpected byte sequence %r!" %
(last_byte + next_byte))
addr += 8 # hack hack hack
met_ff = True
self._description = "[skipped 8 bits after 0xFF] "
bit = stream.readBits(addr, 1, endian)
value <<= 1
value += bit
self._size += 1
addr += 1
self.createValue = lambda: value
self.realvalue = tree[(self.size, value)]
if met_ff:
self._size += 8
def createRawField(parent, size, name="raw[]", description=None):
if size <= 0:
raise FieldError("Unable to create raw field of %s bits" % size)
if (size % 8) == 0:
return RawBytes(parent, name, size // 8, description)
else:
return RawBits(parent, name, size, description)
def createNullField(parent, nbits, name="padding[]", description=None):
if nbits <= 0:
raise FieldError("Unable to create null padding of %s bits" % nbits)
if (nbits % 8) == 0:
return NullBytes(parent, name, nbits // 8, description)
else:
return NullBits(parent, name, nbits, description)
def __init__(self, parent, name, length, description="Raw data"):
assert issubclass(parent.__class__, Field)
if not (0 < length <= MAX_LENGTH):
raise FieldError("Invalid RawBytes length (%s)!" % length)
Field.__init__(self, parent, name, length * 8, description)
self._display = None
def __init__(self, parent, name, signed, size, description=None):
if not (8 <= size <= 16384):
raise FieldError(
"Invalid integer size (%s): have to be in 8..16384" % size)
Bits.__init__(self, parent, name, size, description)
self.signed = signed
def createFields(self):
if self.frame["../type"].value in [0xC0, 0xC1]:
# yay, huffman coding!
if not hasattr(self, "huffman_tables"):
self.huffman_tables = {}
for huffman in self.parent.array("huffman"):
for table in huffman["content"].array("huffman_table"):
for _dummy_ in table:
# exhaust table, so the huffman tree is built
pass
self.huffman_tables[table["table_class"].value,
table["index"].value] = table.tree
components = [] # sos_comp, samples
max_vert = 0
max_horiz = 0
for component in self.scan.array("component"):
for sof_comp in self.frame.array("component"):
if sof_comp["component_id"].value == component[
"component_id"].value:
vert = sof_comp["vert_sample"].value
horiz = sof_comp["horiz_sample"].value
components.append((component, vert * horiz))
max_vert = max(max_vert, vert)
max_horiz = max(max_horiz, horiz)
mcu_height = alignValue(self.frame["height"].value,
8 * max_vert) // (8 * max_vert)
mcu_width = alignValue(self.frame["width"].value,
8 * max_horiz) // (8 * max_horiz)
if self.restart_interval and self.restart_offset > 0:
mcu_number = self.restart_interval * self.restart_offset
else:
mcu_number = 0
initial_mcu = mcu_number
while True:
if (self.restart_interval and mcu_number != initial_mcu and mcu_number % self.restart_interval == 0) or\
mcu_number == mcu_height * mcu_width:
padding = paddingSize(self.current_size, 8)
if padding:
yield PaddingBits(self, "padding[]", padding) # all 1s
last_byte = self.stream.readBytes(
self.absolute_address + self.current_size - 8, 1)
if last_byte == b'\xFF':
next_byte = self.stream.readBytes(
self.absolute_address + self.current_size, 1)
if next_byte != b'\x00':
raise FieldError("Unexpected byte sequence %r!" %
(last_byte + next_byte))
yield NullBytes(self, "stuffed_byte[]", 1)
break
for sos_comp, num_units in components:
for interleave_count in range(num_units):
yield JpegHuffmanImageUnit(
self, "block[%i]component[%i][]" %
(mcu_number, sos_comp["component_id"].value),
self.huffman_tables[
0, sos_comp["dc_coding_table"].value],
self.huffman_tables[
1, sos_comp["ac_coding_table"].value])
mcu_number += 1
else:
self.warning(
"Sorry, only supporting Baseline & Extended Sequential JPEG images so far!"
)
return
def __init__(self,
parent,
name,
format,
description=None,
strip=None,
charset=None,
nbytes=None,
truncate=None):
Bytes.__init__(self, parent, name, 1, description)
# Is format valid?
assert format in self.VALID_FORMATS
# Store options
self._format = format
self._strip = strip
self._truncate = truncate
# Check charset and compute character size in bytes
# (or None when it's not possible to guess character size)
if not charset or charset in self.CHARSET_8BIT:
self._character_size = 1 # one byte per character
elif charset in self.UTF_CHARSET:
self._character_size = None
else:
raise FieldError("Invalid charset for %s: \"%s\"" %
(self.path, charset))
self._charset = charset
# It is a fixed string?
if nbytes is not None:
assert self._format == "fixed"
# Arbitrary limits, just to catch some bugs...
if not (1 <= nbytes <= 0xffff):
raise FieldError("Invalid string size for %s: %s" %
(self.path, nbytes))
self._content_size = nbytes # content length in bytes
self._size = nbytes * 8
self._content_offset = 0
else:
# Format with a suffix: Find the end of the string
if self._format in self.SUFFIX_FORMAT:
self._content_offset = 0
# Choose the suffix
suffix = self.suffix_str
# Find the suffix
length = self._parent.stream.searchBytesLength(
suffix, False, self.absolute_address)
if length is None:
raise FieldError(
"Unable to find end of string %s (format %s)!" %
(self.path, self._format))
if 1 < len(suffix):
# Fix length for little endian bug with UTF-xx charset:
# u"abc" -> "a\0b\0c\0\0\0" (UTF-16-LE)
# search returns length=5, whereas real lenght is 6
length = alignValue(length, len(suffix))
# Compute sizes
self._content_size = length # in bytes
self._size = (length + len(suffix)) * 8
# Format with a prefix: Read prefixed length in bytes
else:
assert self._format in self.PASCAL_FORMATS
# Get the prefix size
prefix_size = self.PASCAL_FORMATS[self._format]
self._content_offset = prefix_size
# Read the prefix and compute sizes
value = self._parent.stream.readBits(self.absolute_address,
prefix_size * 8,
self._parent.endian)
self._content_size = value # in bytes
self._size = (prefix_size + value) * 8
# For UTF-16 and UTF-32, choose the right charset using BOM
if self._charset in self.UTF_CHARSET:
# Charset requires a BOM?
bomsize, endian = self.UTF_CHARSET[self._charset]
if endian == "BOM":
# Read the BOM value
nbytes = bomsize // 8
bom = self._parent.stream.readBytes(self.absolute_address,
nbytes)
# Choose right charset using the BOM
bom_endian = self.UTF_BOM[bomsize]
if bom not in bom_endian:
raise FieldError("String %s has invalid BOM (%s)!" %
(self.path, repr(bom)))
self._charset = bom_endian[bom]
self._content_size -= nbytes
self._content_offset += nbytes
# Compute length in character if possible
if self._character_size:
self._length = self._content_size // self._character_size
else:
self._length = None
