def extend_data(data, length, offset):
"""Extend data using a length and an offset."""
if length >= offset:
new_data = data[-offset:] * (alignValue(length, offset) // offset)
return data + new_data[:length]
else:
return data + data[-offset:-offset + length]
def __init__(self, *args):
FieldSet.__init__(self, *args)
self._size = (8 + alignValue(self["size"].value, 2)) * 8
tag = self["type"].value
if tag in self.TAG_INFO:
self._name, self._description, self._parser = self.TAG_INFO[tag]
else:
self._parser = None
def __init__(self, *args, **kw):
FieldSet.__init__(self, *args, **kw)
try:
self._name, self.handler, self._description = self.TAG_INFO[self["tag"].value]
except KeyError:
self.handler = None
size = self["size"]
self._size = size.address + size.size + alignValue(size.value, 2) * 8
def createFields(self):
if self.has_all_byte:
yield Enum(UInt8(self, "all_defined"), {0: 'False', 1: 'True'})
if self['all_defined'].value:
return
nbytes = alignValue(self.num, 8) // 8
ctr = 0
for i in xrange(nbytes):
for j in reversed(xrange(8)):
yield Bit(self, "bit[%d]" % (ctr + j))
ctr += 8
def setCheckedSizes(self, size):
# First set size so that end is aligned, if needed
self.real_size = size
size *= 8
if self.ALIGN:
size = alignValue(self.absolute_address + size, 8 * self.ALIGN) \
- self.absolute_address
if self._parent._size:
if self._parent.current_size + size > self._parent._size:
size = self._parent._size - self._parent.current_size
self._size = size
def hexadecimal(field):
"""
Convert an integer to hexadecimal in lower case. Returns unicode string.
>>> hexadecimal(type("", (), dict(value=412, size=16)))
u'0x019c'
>>> hexadecimal(type("", (), dict(value=0, size=32)))
u'0x00000000'
"""
assert hasattr(field, "value") and hasattr(field, "size")
size = field.size
padding = alignValue(size, 4) // 4
pattern = u"0x%%0%ux" % padding
return pattern % field.value
def __init__(self, *args, **kw):
FieldSet.__init__(self, *args, **kw)
self._size = (8 + alignValue(self["size"].value, 2)) * 8
tag = self["tag"].value
if tag in self.TAG_INFO:
self.tag_info = self.TAG_INFO[tag]
if tag == "LIST":
subtag = self["subtag"].value
if subtag in self.subtag_info:
info = self.subtag_info[subtag]
self.tag_info = (info[0], None, info[1])
self._name = self.tag_info[0]
self._description = self.tag_info[2]
else:
self.tag_info = ("field[]", None, None)
def readBits(self, address, nbits, endian):
assert endian in (BIG_ENDIAN, LITTLE_ENDIAN, MIDDLE_ENDIAN)
if endian is MIDDLE_ENDIAN:
# read an aligned chunk of words
wordaddr, remainder = divmod(address, 16)
wordnbits = alignValue(remainder + nbits, 16)
_, data, missing = self.read(wordaddr * 16, wordnbits)
shift = remainder
else:
shift, data, missing = self.read(address, nbits)
if missing:
raise ReadStreamError(nbits, address)
value = str2long(data, endian)
if endian in (BIG_ENDIAN, MIDDLE_ENDIAN):
value >>= len(data) * 8 - shift - nbits
else:
value >>= shift
return value & (1 << nbits) - 1
def createFields(self):
yield String(self, "signature", 4, "8BIM signature", charset="ASCII")
if self["signature"].value != "8BIM":
raise ParserError("Stream doesn't look like 8BIM item (wrong signature)!")
yield textHandler(UInt16(self, "tag"), hexadecimal)
if self.stream.readBytes(self.absolute_address + self.current_size, 4) != "\0\0\0\0":
yield PascalString8(self, "name")
size = 2 + (self["name"].size // 8) % 2
yield NullBytes(self, "name_padding", size)
else:
yield String(self, "name", 4, strip="\0")
yield UInt16(self, "size")
size = alignValue(self["size"].value, 2)
if not size:
return
if self.handler:
if issubclass(self.handler, FieldSet):
yield self.handler(self, "content", size=size * 8)
else:
yield self.handler(self, "content")
else:
yield RawBytes(self, "content", size)
def __init__(self, parent, name):
FieldSet.__init__(self, parent, name)
self._size = alignValue(self["size"].value, 4) * 8
def __init__(self, parent, name, is_32bit=True):
FieldSet.__init__(self, parent, name)
self._size = alignValue(self["size"].value, 4) * 8
self.is_32bit = is_32bit
def __init__(self, parent, name, width, pixel_class):
FieldSet.__init__(self, parent, name)
self._pixel = pixel_class
self._width = width
self._size = alignValue(self._width * self._pixel.static_size, 32)
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
