"""
InfoTech Storage Format (ITSF) parser, used by Microsoft's HTML Help (.chm)
Document:
- Microsoft's HTML Help (.chm) format
http://www.wotsit.org (search "chm")
- chmlib library
http://www.jedrea.com/chmlib/
Author: Victor Stinner
Creation date: 2007-03-04
"""
from hachoir_parser import Parser
from hachoir_core.field import (Field, FieldSet, ParserError,
Int32, UInt32, UInt64,
RawBytes, PaddingBytes,
Enum, String)
from hachoir_core.endian import LITTLE_ENDIAN
from hachoir_parser.common.win32 import GUID
from hachoir_parser.common.win32_lang_id import LANGUAGE_ID
from hachoir_core.text_handler import textHandler, hexadecimal, filesizeHandler
class CWord(Field):
"""
Compressed double-word
"""
def __init__(self, parent, name, description=None):
Field.__init__(self, parent, name, 8, description)
endian = self._parent.endian
stream = self._parent.stream
addr = self.absolute_address
value = 0
byte = stream.readBits(addr, 8, endian)
while byte & 0x80:
value <<= 7
value += (byte & 0x7f)
self._size += 8
if 64 < self._size:
raise ParserError("CHM: CWord is limited to 64 bits")
addr += 8
byte = stream.readBits(addr, 8, endian)
value += byte
self.createValue = lambda: value
class Filesize_Header(FieldSet):
def createFields(self):
yield textHandler(UInt32(self, "unknown[]", "0x01FE"), hexadecimal)
yield textHandler(UInt32(self, "unknown[]", "0x0"), hexadecimal)
yield filesizeHandler(UInt64(self, "file_size"))
yield textHandler(UInt32(self, "unknown[]", "0x0"), hexadecimal)
yield textHandler(UInt32(self, "unknown[]", "0x0"), hexadecimal)
class ITSP(FieldSet):
def __init__(self, *args):
FieldSet.__init__(self, *args)
self._size = self["size"].value * 8
def createFields(self):
yield String(self, "magic", 4, "ITSP", charset="ASCII")
yield UInt32(self, "version", "Version (=1)")
yield filesizeHandler(UInt32(self, "size", "Length (in bytes) of the directory header (84)"))
yield UInt32(self, "unknown[]", "(=10)")
yield filesizeHandler(UInt32(self, "block_size", "Directory block size"))
yield UInt32(self, "density", "Density of quickref section, usually 2")
yield UInt32(self, "index_depth", "Depth of the index tree")
yield Int32(self, "nb_dir", "Chunk number of root index chunk")
yield UInt32(self, "first_pmgl", "Chunk number of first PMGL (listing) chunk")
yield UInt32(self, "last_pmgl", "Chunk number of last PMGL (listing) chunk")
yield Int32(self, "unknown[]", "-1")
yield UInt32(self, "nb_dir_chunk", "Number of directory chunks (total)")
yield Enum(UInt32(self, "lang_id", "Windows language ID"), LANGUAGE_ID)
yield GUID(self, "system_uuid", "{5D02926A-212E-11D0-9DF9-00A0C922E6EC}")
yield filesizeHandler(UInt32(self, "size2", "Same value than size"))
yield Int32(self, "unknown[]", "-1")
yield Int32(self, "unknown[]", "-1")
yield Int32(self, "unknown[]", "-1")
class ITSF(FieldSet):
def createFields(self):
yield String(self, "magic", 4, "ITSF", charset="ASCII")
yield UInt32(self, "version")
yield UInt32(self, "header_size", "Total header length (in bytes)")
yield UInt32(self, "one")
yield UInt32(self, "last_modified")
yield Enum(UInt32(self, "lang_id", "Windows Language ID"), LANGUAGE_ID)
yield GUID(self, "dir_uuid", "{7C01FD10-7BAA-11D0-9E0C-00A0-C922-E6EC}")
yield GUID(self, "stream_uuid", "{7C01FD11-7BAA-11D0-9E0C-00A0-C922-E6EC}")
yield UInt64(self, "filesize_offset")
yield filesizeHandler(UInt64(self, "filesize_len"))
yield UInt64(self, "dir_offset")
yield filesizeHandler(UInt64(self, "dir_len"))
if 3 <= self["version"].value:
yield UInt64(self, "data_offset")
class PMGL_Entry(FieldSet):
def createFields(self):
yield CWord(self, "name_len")
yield String(self, "name", self["name_len"].value, charset="UTF-8")
yield CWord(self, "space")
yield CWord(self, "start")
yield filesizeHandler(CWord(self, "length"))
def createDescription(self):
return "%s (%s)" % (self["name"].value, self["length"].display)
class PMGL(FieldSet):
def createFields(self):
# Header
yield String(self, "magic", 4, "PMGL", charset="ASCII")
yield filesizeHandler(Int32(self, "free_space",
"Length of free space and/or quickref area at end of directory chunk"))
yield Int32(self, "unknown")
yield Int32(self, "previous", "Chunk number of previous listing chunk")
yield Int32(self, "next", "Chunk number of previous listing chunk")
# Entries
stop = self.size - self["free_space"].value * 8
while self.current_size < stop:
yield PMGL_Entry(self, "entry[]")
# Padding
padding = (self.size - self.current_size) // 8
if padding:
yield PaddingBytes(self, "padding", padding)
class PMGI_Entry(FieldSet):
def createFields(self):
yield CWord(self, "name_len")
yield String(self, "name", self["name_len"].value, charset="UTF-8")
yield CWord(self, "page")
def createDescription(self):
return "%s (page #%u)" % (self["name"].value, self["page"].value)
class PMGI(FieldSet):
def createFields(self):
yield String(self, "magic", 4, "PMGI", charset="ASCII")
yield filesizeHandler(UInt32(self, "free_space",
"Length of free space and/or quickref area at end of directory chunk"))
stop = self.size - self["free_space"].value * 8
while self.current_size < stop:
yield PMGI_Entry(self, "entry[]")
padding = (self.size - self.current_size) // 8
if padding:
yield PaddingBytes(self, "padding", padding)
class Directory(FieldSet):
def createFields(self):
yield ITSP(self, "itsp")
block_size = self["itsp/block_size"].value * 8
nb_dir = self["itsp/nb_dir"].value
if nb_dir < 0:
nb_dir = 1
for index in xrange(nb_dir):
yield PMGL(self, "pmgl[]", size=block_size)
if self.current_size < self.size:
yield PMGI(self, "pmgi", size=block_size)
class ChmFile(Parser):
PARSER_TAGS = {
"id": "chm",
"category": "misc",
"file_ext": ("chm",),
"min_size": 4*8,
"magic": (("ITSF\3\0\0\0", 0),),
"description": "Microsoft's HTML Help (.chm)",
}
endian = LITTLE_ENDIAN
def validate(self):
if self.stream.readBytes(0, 4) != "ITSF":
return "Invalid magic"
if self["itsf/version"].value != 3:
return "Invalid version"
return True
def createFields(self):
yield ITSF(self, "itsf")
yield Filesize_Header(self, "file_size", size=self["itsf/filesize_len"].value*8)
padding = self.seekByte(self["itsf/dir_offset"].value)
if padding:
yield padding
yield Directory(self, "dir", size=self["itsf/dir_len"].value*8)
size = (self.size - self.current_size) // 8
if size:
yield RawBytes(self, "raw_end", size)
def createContentSize(self):
return self["file_size/file_size"].value * 8
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