OleFileIO_PL.py

#!/usr/local/bin/python
# -*- coding: latin-1 -*-
"""
OleFileIO_PL:
    Module to read Microsoft OLE2 files (also called Structured Storage or
    Microsoft Compound Document File Format), such as Microsoft Office
    documents, Image Composer and FlashPix files, Outlook messages, ...

version 0.21 2010-01-22 Philippe Lagadec - http://www.decalage.info

Project website: http://www.decalage.info/python/olefileio

Improved version of the OleFileIO module from PIL library v1.1.6
See: http://www.pythonware.com/products/pil/index.htm

The Python Imaging Library (PIL) is
    Copyright (c) 1997-2005 by Secret Labs AB
    Copyright (c) 1995-2005 by Fredrik Lundh
OleFileIO_PL changes are Copyright (c) 2005-2010 by Philippe Lagadec

See source code and LICENSE.txt for information on usage and redistribution.

WARNING: THIS IS (STILL) WORK IN PROGRESS.
"""

__author__  = "Fredrik Lundh (Secret Labs AB), Philippe Lagadec"
__date__    = "2010-01-22"
__version__ = '0.21'

#--- LICENSE ------------------------------------------------------------------

# OleFileIO_PL is an improved version of the OleFileIO module from the
# Python Imaging Library (PIL).

# OleFileIO_PL changes are Copyright (c) 2005-2010 by Philippe Lagadec
#
# The Python Imaging Library (PIL) is
#    Copyright (c) 1997-2005 by Secret Labs AB
#    Copyright (c) 1995-2005 by Fredrik Lundh
#
# By obtaining, using, and/or copying this software and/or its associated
# documentation, you agree that you have read, understood, and will comply with
# the following terms and conditions:
#
# Permission to use, copy, modify, and distribute this software and its
# associated documentation for any purpose and without fee is hereby granted,
# provided that the above copyright notice appears in all copies, and that both
# that copyright notice and this permission notice appear in supporting
# documentation, and that the name of Secret Labs AB or the author(s) not be used
# in advertising or publicity pertaining to distribution of the software
# without specific, written prior permission.
#
# SECRET LABS AB AND THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
# SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
# IN NO EVENT SHALL SECRET LABS AB OR THE AUTHORS BE LIABLE FOR ANY SPECIAL,
# INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
# OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
# PERFORMANCE OF THIS SOFTWARE.

#-----------------------------------------------------------------------------
# CHANGELOG: (only OleFileIO_PL changes compared to PIL 1.1.6)
# 2005-05-11 v0.10 PL: - a few fixes for Python 2.4 compatibility
#                        (all changes flagged with [PL])
# 2006-02-22 v0.11 PL: - a few fixes for some Office 2003 documents which raise
#                        exceptions in _OleStream.__init__()
# 2006-06-09 v0.12 PL: - fixes for files above 6.8MB (DIFAT in loadfat)
#                      - added some constants
#                      - added header values checks
#                      - added some docstrings
#                      - getsect: bugfix in case sectors >512 bytes
#                      - getsect: added conformity checks
#                      - DEBUG_MODE constant to activate debug display
# 2007-09-04 v0.13 PL: - improved/translated (lots of) comments
#                      - updated license
#                      - converted tabs to 4 spaces
# 2007-11-19 v0.14 PL: - added OleFileIO._raise_defect() to adapt sensitivity
#                      - improved _unicode() to use Python 2.x unicode support
#                      - fixed bug in _OleDirectoryEntry
# 2007-11-25 v0.15 PL: - added safety checks to detect FAT loops
#                      - fixed _OleStream which didn't check stream size
#                      - added/improved many docstrings and comments
#                      - moved helper functions _unicode and _clsid out of
#                        OleFileIO class
#                      - improved OleFileIO._find() to add Unix path syntax
#                      - OleFileIO._find() is now case-insensitive
#                      - added get_type() and get_rootentry_name()
#                      - rewritten loaddirectory and _OleDirectoryEntry
# 2007-11-27 v0.16 PL: - added _OleDirectoryEntry.kids_dict
#                      - added detection of duplicate filenames in storages
#                      - added detection of duplicate references to streams
#                      - added get_size() and exists() to _OleDirectoryEntry
#                      - added isOleFile to check header before parsing
#                      - added __all__ list to control public keywords in pydoc
# 2007-12-04 v0.17 PL: - added _load_direntry to fix a bug in loaddirectory
#                      - improved _unicode(), added workarounds for Python <2.3
#                      - added set_debug_mode and -d option to set debug mode
#                      - fixed bugs in OleFileIO.open and _OleDirectoryEntry
#                      - added safety check in main for large or binary
#                        properties
#                      - allow size>0 for storages for some implementations
# 2007-12-05 v0.18 PL: - fixed several bugs in handling of FAT, MiniFAT and
#                        streams
#                      - added option '-c' in main to check all streams
# 2009-12-10 v0.19 PL: - bugfix for 32 bit arrays on 64 bits platforms
#                        (thanks to Ben G. and Martijn for reporting the bug)
# 2009-12-11 v0.20 PL: - bugfix in OleFileIO.open when filename is not plain str
# 2010-01-22 v0.21 PL: - added support for big-endian CPUs such as PowerPC Macs

#-----------------------------------------------------------------------------
# TODO (for version 1.0):
# - TESTS with Linux, MacOSX, Python 1.5.2, various files, PIL, ...
# - add underscore to each private method, to avoid their display in
#   pydoc/epydoc documentation
# - replace all raised exceptions with _raise_defect (at least in OleFileIO)
# - merge code from _OleStream and OleFileIO.getsect to read sectors
#   (maybe add a class for FAT and MiniFAT ?)
# - add method to check all streams (follow sectors chains without storing all
#   stream in memory, and report anomalies)
# - use _OleDirectoryEntry.kids_dict to improve _find and _list ?
# - fix Unicode names handling (find some way to stay compatible with Py1.5.2)
#   => if possible avoid converting names to Latin-1
# - review DIFAT code: fix handling of DIFSECT blocks in FAT (not stop)
# - rewrite OleFileIO.getproperties
# - improve docstrings to show more sample uses
# - see also original notes and FIXME below
# - remove all obsolete FIXMEs

# IDEAS:
# - allow _raise_defect to raise different exceptions, not only IOError
# - provide a class with named attributes to get well-known properties of
#   MS Office documents (title, author, ...) ?
# - in OleFileIO._open and _OleStream, use size=None instead of 0x7FFFFFFF for
#   streams with unknown size
# - use arrays of int instead of long integers for FAT/MiniFAT, to improve
#   performance and reduce memory usage ? (possible issue with values >2^31)
# - provide tests with unittest (may need write support to create samples)
# - move all debug code (and maybe dump methods) to a separate module, with
#   a class which inherits OleFileIO ?
# - fix docstrings to follow epydoc format
# - add support for 4K sectors ?
# - add support for big endian byte order ?
# - create a simple OLE explorer with wxPython

# FUTURE EVOLUTIONS to add write support:
# 1) add ability to write a stream back on disk from StringIO (same size, no
#    change in FAT/MiniFAT).
# 2) rename a stream/storage if it doesn't change the RB tree
# 3) use rbtree module to update the red-black tree + any rename
# 4) remove a stream/storage: free sectors in FAT/MiniFAT
# 5) allocate new sectors in FAT/MiniFAT
# 6) create new storage/stream
#-----------------------------------------------------------------------------

#
# THIS IS WORK IN PROGRESS
#
# The Python Imaging Library
# $Id: OleFileIO.py 2339 2005-03-25 08:02:17Z fredrik $
#
# stuff to deal with OLE2 Structured Storage files.  this module is
# used by PIL to read Image Composer and FlashPix files, but can also
# be used to read other files of this type.
#
# History:
# 1997-01-20 fl   Created
# 1997-01-22 fl   Fixed 64-bit portability quirk
# 2003-09-09 fl   Fixed typo in OleFileIO.loadfat (noted by Daniel Haertle)
# 2004-02-29 fl   Changed long hex constants to signed integers
#
# Notes:
# FIXME: sort out sign problem (eliminate long hex constants)
# FIXME: change filename to use "a/b/c" instead of ["a", "b", "c"]
# FIXME: provide a glob mechanism function (using fnmatchcase)
#
# Literature:
#
# "FlashPix Format Specification, Appendix A", Kodak and Microsoft,
#  September 1996.
#
# Quotes:
#
# "If this document and functionality of the Software conflict,
#  the actual functionality of the Software represents the correct
#  functionality" -- Microsoft, in the OLE format specification
#
# Copyright (c) Secret Labs AB 1997.
# Copyright (c) Fredrik Lundh 1997.
#
# See the README file for information on usage and redistribution.
#

#------------------------------------------------------------------------------

import string, StringIO, struct, array, os.path, sys

#[PL] Define explicitly the public API to avoid private objects in pydoc:
__all__ = ['OleFileIO', 'isOleFile']

#[PL] workaround to fix an issue with array item size on 64 bits systems:
if array.array('L').itemsize == 4:
    # on 32 bits platforms, long integers in an array are 32 bits:
    UINT32 = 'L'
elif array.array('I').itemsize == 4:
    # on 64 bits platforms, integers in an array are 32 bits:
    UINT32 = 'I'
else:
    raise ValueError, 'Need to fix a bug with 32 bit arrays, please contact author...'


#[PL] These workarounds were inspired from the Path module
# (see http://www.jorendorff.com/articles/python/path/)
#TODO: test with old Python versions

# Pre-2.3 workaround for booleans
try:
    True, False
except NameError:
    True, False = 1, 0

# Pre-2.3 workaround for basestring.
try:
    basestring
except NameError:
    try:
        # is Unicode supported (Python >2.0 or >1.6 ?)
        basestring = (str, unicode)
    except NameError:
        basestring = str

#[PL] Experimental setting: if True, OLE filenames will be kept in Unicode
# if False (default PIL behaviour), all filenames are converted to Latin-1.
KEEP_UNICODE_NAMES = False

#[PL] DEBUG display mode: False by default, use set_debug_mode() or "-d" on
# command line to change it.
DEBUG_MODE = False
def debug_print(msg):
    print msg
def debug_pass(msg):
    pass
debug = debug_pass

def set_debug_mode(debug_mode):
    """
    Set debug mode on or off, to control display of debugging messages.
    mode: True or False
    """
    global DEBUG_MODE, debug
    DEBUG_MODE = debug_mode
    if debug_mode:
        debug = debug_print
    else:
        debug = debug_pass

#TODO: convert this to hex
MAGIC = '\320\317\021\340\241\261\032\341'

#[PL]: added constants for Sector IDs (from AAF specifications)
MAXREGSECT = 0xFFFFFFFAL; # maximum SECT
DIFSECT    = 0xFFFFFFFCL; # (-4) denotes a DIFAT sector in a FAT
FATSECT    = 0xFFFFFFFDL; # (-3) denotes a FAT sector in a FAT
ENDOFCHAIN = 0xFFFFFFFEL; # (-2) end of a virtual stream chain
FREESECT   = 0xFFFFFFFFL; # (-1) unallocated sector

#[PL]: added constants for Directory Entry IDs (from AAF specifications)
MAXREGSID  = 0xFFFFFFFAL; # maximum directory entry ID
NOSTREAM   = 0xFFFFFFFFL; # (-1) unallocated directory entry

#[PL] object types in storage (from AAF specifications)
STGTY_EMPTY     = 0 # empty directory entry (according to OpenOffice.org doc)
STGTY_STORAGE   = 1 # element is a storage object
STGTY_STREAM    = 2 # element is a stream object
STGTY_LOCKBYTES = 3 # element is an ILockBytes object
STGTY_PROPERTY  = 4 # element is an IPropertyStorage object
STGTY_ROOT      = 5 # element is a root storage


#
# --------------------------------------------------------------------
# property types

VT_EMPTY=0; VT_NULL=1; VT_I2=2; VT_I4=3; VT_R4=4; VT_R8=5; VT_CY=6;
VT_DATE=7; VT_BSTR=8; VT_DISPATCH=9; VT_ERROR=10; VT_BOOL=11;
VT_VARIANT=12; VT_UNKNOWN=13; VT_DECIMAL=14; VT_I1=16; VT_UI1=17;
VT_UI2=18; VT_UI4=19; VT_I8=20; VT_UI8=21; VT_INT=22; VT_UINT=23;
VT_VOID=24; VT_HRESULT=25; VT_PTR=26; VT_SAFEARRAY=27; VT_CARRAY=28;
VT_USERDEFINED=29; VT_LPSTR=30; VT_LPWSTR=31; VT_FILETIME=64;
VT_BLOB=65; VT_STREAM=66; VT_STORAGE=67; VT_STREAMED_OBJECT=68;
VT_STORED_OBJECT=69; VT_BLOB_OBJECT=70; VT_CF=71; VT_CLSID=72;
VT_VECTOR=0x1000;

# map property id to name (for debugging purposes)

VT = {}
for keyword, var in vars().items():
    if keyword[:3] == "VT_":
        VT[var] = keyword

#
# --------------------------------------------------------------------
# Some common document types (root.clsid fields)

WORD_CLSID = "00020900-0000-0000-C000-000000000046"
#TODO: check Excel, PPT, ...

#[PL]: Defect levels to classify parsing errors - see OleFileIO._raise_defect()
DEFECT_UNSURE =    10    # a case which looks weird, but not sure it's a defect
DEFECT_POTENTIAL = 20    # a potential defect
DEFECT_INCORRECT = 30    # an error according to specifications, but parsing
                         # can go on
DEFECT_FATAL =     40    # an error which cannot be ignored, parsing is
                         # impossible

#[PL] add useful constants to __all__:
for key in vars().keys():
    if key.startswith('STGTY_') or key.startswith('DEFECT_'):
        __all__.append(key)


#--- FUNCTIONS ----------------------------------------------------------------

def isOleFile (filename):
    """
    Test if file is an OLE container (according to its header).
    filename: file name or path (str, unicode)
    return: True if OLE, False otherwise.
    """
    f = open(filename, 'rb')
    header = f.read(len(MAGIC))
    if header == MAGIC:
        return True
    else:
        return False


#TODO: replace i16 and i32 with more readable struct.unpack equivalent
def i16(c, o = 0):
    """
    Converts a 2-bytes (16 bits) string to an integer.

    c: string containing bytes to convert
    o: offset of bytes to convert in string
    """
    return ord(c[o])+(ord(c[o+1])<<8)


def i32(c, o = 0):
    """
    Converts a 4-bytes (32 bits) string to an integer.

    c: string containing bytes to convert
    o: offset of bytes to convert in string
    """
    return int(ord(c[o])+(ord(c[o+1])<<8)+(ord(c[o+2])<<16)+(ord(c[o+3])<<24))
    # [PL]: added int() because "<<" gives long int since Python 2.4


def _clsid(clsid):
    """
    Converts a CLSID to a human-readable string.
    clsid: string of length 16.
    """
    assert len(clsid) == 16
    if clsid == "\0" * len(clsid):
        return ""
    return (("%08X-%04X-%04X-%02X%02X-" + "%02X" * 6) %
            ((i32(clsid, 0), i16(clsid, 4), i16(clsid, 6)) +
            tuple(map(ord, clsid[8:16]))))



# UNICODE support for Old Python versions:
# (necessary to handle storages/streams names which use Unicode)

try:
    # is Unicode supported ?
    unicode

    def _unicode(s, errors='replace'):
        """
        Map unicode string to Latin 1. (Python with Unicode support)

        s: UTF-16LE unicode string to convert to Latin-1
        errors: 'replace', 'ignore' or 'strict'. See Python doc for unicode()
        """
        #TODO: test if it OleFileIO works with Unicode strings, instead of
        #      converting to Latin-1.
        try:
            # First the string is converted to plain Unicode:
            # (assuming it is encoded as UTF-16 little-endian)
            u = s.decode('UTF-16LE', errors)
            if KEEP_UNICODE_NAMES:
                return u
            else:
                # Second the unicode string is converted to Latin-1
                return u.encode('latin_1', errors)
        except:
            # there was an error during Unicode to Latin-1 conversion:
            raise IOError, 'incorrect Unicode name'

except NameError:
    def _unicode(s, errors='replace'):
        """
        Map unicode string to Latin 1. (Python without native Unicode support)

        s: UTF-16LE unicode string to convert to Latin-1
        errors: 'replace', 'ignore' or 'strict'. (ignored in this version)
        """
        # If the unicode function does not exist, we assume this is an old
        # Python version without Unicode support.
        # Null bytes are simply removed (this only works with usual Latin-1
        # strings which do not contain unicode characters>256):
        return filter(ord, s)




#=== CLASSES ==================================================================

#--- _OleStream ---------------------------------------------------------------

class _OleStream(StringIO.StringIO):
    """
    OLE2 Stream

    Returns a read-only file object which can be used to read
    the contents of a OLE stream (instance of the StringIO class).
    To open a stream, use the openstream method in the OleFile class.

    This function can be used with either ordinary streams,
    or ministreams, depending on the offset, sectorsize, and
    fat table arguments.

    Attributes:
        - size: actual size of data stream, after it was opened.
    """

    # FIXME: should store the list of sects obtained by following
    # the fat chain, and load new sectors on demand instead of
    # loading it all in one go.

    def __init__(self, fp, sect, size, offset, sectorsize, fat):
        """
        Constructor for _OleStream class.

        fp        : file object, the OLE container or the MiniFAT stream
        sect      : sector index of first sector in the stream
        size      : total size of the stream
        offset    : offset in bytes for the first FAT or MiniFAT sector
        sectorsize: size of one sector
        fat       : array/list of sector indexes (FAT or MiniFAT)
        return    : a StringIO instance containing the OLE stream
        """
        debug('_OleStream.__init__:')
        debug('  sect=%d (%X), size=%d, offset=%d, sectorsize=%d, len(fat)=%d, fp=%s'
            %(sect,sect,size,offset,sectorsize,len(fat), repr(fp)))
        # for debugging messages, size of file where stream is read:
        if isinstance(fp, StringIO.StringIO):
            filesize = len(fp.getvalue())   # file in MiniFAT
        else:
            filesize = os.path.getsize(fp.name) # file on disk
        #[PL] To detect malformed documents with FAT loops, we compute the
        # expected number of sectors in the stream:
        unknown_size = False
        if size==0x7FFFFFFF:
            # this is the case when called from OleFileIO._open(), and stream
            # size is not known in advance (for example when reading the
            # Directory stream). Then we can only guess maximum size:
            size = len(fat)*sectorsize
            # and we keep a record that size was unknown:
            unknown_size = True
            debug('  stream with UNKNOWN SIZE')
        nb_sectors = (size + (sectorsize-1)) / sectorsize
        debug('nb_sectors = %d' % nb_sectors)
        # This number should (at least) be less than the total number of
        # sectors in the given FAT:
        if nb_sectors > len(fat):
            raise IOError, 'malformed OLE document, stream too large'
        # optimization(?): data is first a list of strings, and join() is called
        # at the end to concatenate all in one string.
        # (this may not be really useful with recent Python versions)
        data = []
        # if size is zero, then first sector index should be ENDOFCHAIN:
        if size == 0 and sect != ENDOFCHAIN:
            debug('size == 0 and sect != ENDOFCHAIN:')
            raise IOError, 'incorrect OLE sector index for empty stream'
        #[PL] A fixed-length for loop is used instead of an undefined while
        # loop to avoid DoS attacks:
        for i in xrange(nb_sectors):
            # Sector index may be ENDOFCHAIN, but only if size was unknown
            if sect == ENDOFCHAIN:
                if unknown_size:
                    break
                else:
                    # else this means that the stream is smaller than declared:
                    debug('sect=ENDOFCHAIN before expected size')
                    raise IOError, 'incomplete OLE stream'
            # sector index should be within FAT:
            if sect<0 or sect>=len(fat):
                debug('sect=%d (%X) / len(fat)=%d' % (sect, sect, len(fat)))
                debug('i=%d / nb_sectors=%d' %(i, nb_sectors))
##                tmp_data = string.join(data, "")
##                f = open('test_debug.bin', 'wb')
##                f.write(tmp_data)
##                f.close()
##                debug('data read so far: %d bytes' % len(tmp_data))
                raise IOError, 'incorrect OLE FAT, sector index out of range'
            #TODO: merge this code with OleFileIO.getsect() ?
            #TODO: check if this works with 4K sectors:
            try:
                fp.seek(offset + sectorsize * sect)
            except:
                debug('sect=%d, seek=%d, filesize=%d' %
                    (sect, offset+sectorsize*sect, filesize))
                raise IOError, 'OLE sector index out of range'
            sector_data = fp.read(sectorsize)
            # [PL] check if there was enough data:
            # Note: if sector is the last of the file, sometimes it is not a
            # complete sector (of 512 or 4K), so we may read less than
            # sectorsize.
            if len(sector_data)!=sectorsize and sect!=(len(fat)-1):
                debug('sect=%d / len(fat)=%d, seek=%d / filesize=%d, len read=%d' %
                    (sect, len(fat), offset+sectorsize*sect, filesize, len(sector_data)))
                debug('seek+len(read)=%d' % (offset+sectorsize*sect+len(sector_data)))
                raise IOError, 'incomplete OLE sector'
            data.append(sector_data)
            # jump to next sector in the FAT:
            try:
                sect = fat[sect]
            except IndexError:
                # [PL] if pointer is out of the FAT an exception is raised
                raise IOError, 'incorrect OLE FAT, sector index out of range'
        #[PL] Last sector should be a "end of chain" marker:
        if sect != ENDOFCHAIN:
            raise IOError, 'incorrect last sector index in OLE stream'
        data = string.join(data, "")
        # Data is truncated to the actual stream size:
        if len(data) >= size:
            data = data[:size]
            # actual stream size is stored for future use:
            self.size = size
        elif unknown_size:
            # actual stream size was not known, now we know the size of read
            # data:
            self.size = len(data)
        else:
            # read data is less than expected:
            debug('len(data)=%d, size=%d' % (len(data), size))
            raise IOError, 'OLE stream size is less than declared'
        # when all data is read in memory, StringIO constructor is called
        StringIO.StringIO.__init__(self, data)
        # Then the _OleStream object can be used as a read-only file object.


#--- _OleDirectoryEntry -------------------------------------------------------

class _OleDirectoryEntry:

    """
    OLE2 Directory Entry
    """
    #[PL] parsing code moved from OleFileIO.loaddirectory

    # struct to parse directory entries:
    # <: little-endian byte order
    # 64s: string containing entry name in unicode (max 31 chars) + null char
    # H: uint16, number of bytes used in name buffer, including null = (len+1)*2
    # B: uint8, dir entry type (between 0 and 5)
    # B: uint8, color: 0=black, 1=red
    # I: uint32, index of left child node in the red-black tree, NOSTREAM if none
    # I: uint32, index of right child node in the red-black tree, NOSTREAM if none
    # I: uint32, index of child root node if it is a storage, else NOSTREAM
    # 16s: CLSID, unique identifier (only used if it is a storage)
    # I: uint32, user flags
    # 8s: uint64, creation timestamp or zero
    # 8s: uint64, modification timestamp or zero
    # I: uint32, SID of first sector if stream or ministream, SID of 1st sector
    #    of stream containing ministreams if root entry, 0 otherwise
    # I: uint32, total stream size in bytes if stream (low 32 bits), 0 otherwise
    # I: uint32, total stream size in bytes if stream (high 32 bits), 0 otherwise
    STRUCT_DIRENTRY = '<64sHBBIII16sI8s8sIII'
    # size of a directory entry: 128 bytes
    DIRENTRY_SIZE = 128
    assert struct.calcsize(STRUCT_DIRENTRY) == DIRENTRY_SIZE


    def __init__(self, entry, sid, olefile):
        """
        Constructor for an _OleDirectoryEntry object.
        Parses a 128-bytes entry from the OLE Directory stream.

        entry  : string (must be 128 bytes long)
        sid    : index of this directory entry in the OLE file directory
        olefile: OleFileIO containing this directory entry
        """
        self.sid = sid
        # ref to olefile is stored for future use
        self.olefile = olefile
        # kids is a list of children entries, if this entry is a storage:
        # (list of _OleDirectoryEntry objects)
        self.kids = []
        # kids_dict is a dictionary of children entries, indexed by their
        # name in lowercase: used to quickly find an entry, and to detect
        # duplicates
        self.kids_dict = {}
        # flag used to detect if the entry is referenced more than once in
        # directory:
        self.used = False
        # decode DirEntry
        (
            name,
            namelength,
            self.entry_type,
            self.color,
            self.sid_left,
            self.sid_right,
            self.sid_child,
            clsid,
            self.dwUserFlags,
            self.createTime,
            self.modifyTime,
            self.isectStart,
            sizeLow,
            sizeHigh
        ) = struct.unpack(_OleDirectoryEntry.STRUCT_DIRENTRY, entry)
        if self.entry_type not in [STGTY_ROOT, STGTY_STORAGE, STGTY_STREAM, STGTY_EMPTY]:
            olefile._raise_defect(DEFECT_INCORRECT, 'unhandled OLE storage type')
        # only first directory entry can (and should) be root:
        if self.entry_type == STGTY_ROOT and sid != 0:
            olefile._raise_defect(DEFECT_INCORRECT, 'duplicate OLE root entry')
        if sid == 0 and self.entry_type != STGTY_ROOT:
            olefile._raise_defect(DEFECT_INCORRECT, 'incorrect OLE root entry')
        #debug (struct.unpack(fmt_entry, entry[:len_entry]))
        # name should be at most 31 unicode characters + null character,
        # so 64 bytes in total (31*2 + 2):
        if namelength>64:
            olefile._raise_defect(DEFECT_INCORRECT, 'incorrect DirEntry name length')
            # if exception not raised, namelength is set to the maximum value:
            namelength = 64
        # only characters without ending null char are kept:
        name = name[:(namelength-2)]
        # name is converted from unicode to Latin-1:
        self.name = _unicode(name)

        debug('DirEntry SID=%d: %s' % (self.sid, repr(self.name)))
        debug(' - type: %d' % self.entry_type)
        debug(' - sect: %d' % self.isectStart)
        debug(' - SID left: %d, right: %d, child: %d' % (self.sid_left,
            self.sid_right, self.sid_child))

        # sizeHigh is only used for 4K sectors, it should be zero for 512 bytes
        # sectors, BUT apparently some implementations set it as 0xFFFFFFFFL, 1
        # or some other value so it cannot be raised as a defect in general:
        if olefile.sectorsize == 512:
            if sizeHigh != 0 and sizeHigh != 0xFFFFFFFFL:
                debug('sectorsize=%d, sizeLow=%d, sizeHigh=%d (%X)' %
                    (olefile.sectorsize, sizeLow, sizeHigh, sizeHigh))
                olefile._raise_defect(DEFECT_UNSURE, 'incorrect OLE stream size')
            self.size = sizeLow
        else:
            self.size = sizeLow + (long(sizeHigh)<<32)
        debug(' - size: %d (sizeLow=%d, sizeHigh=%d)' % (self.size, sizeLow, sizeHigh))

        self.clsid = _clsid(clsid)
        # a storage should have a null size, BUT some implementations such as
        # Word 8 for Mac seem to allow non-null values => Potential defect:
        if self.entry_type == STGTY_STORAGE and self.size != 0:
            olefile._raise_defect(DEFECT_POTENTIAL, 'OLE storage with size>0')
        # check if stream is not already referenced elsewhere:
        if self.entry_type in (STGTY_ROOT, STGTY_STREAM) and self.size>0:
            if self.size < olefile.minisectorcutoff \
            and self.entry_type==STGTY_STREAM: # only streams can be in MiniFAT
                # ministream object
                minifat = True
            else:
                minifat = False
            olefile._check_duplicate_stream(self.isectStart, minifat)



    def build_storage_tree(self):
        """
        Read and build the red-black tree attached to this _OleDirectoryEntry
        object, if it is a storage.
        Note that this method builds a tree of all subentries, so it should
        only be called for the root object once.
        """
        debug('build_storage_tree: SID=%d - %s - sid_child=%d'
            % (self.sid, repr(self.name), self.sid_child))
        if self.sid_child != NOSTREAM:
            # if child SID is not NOSTREAM, then this entry is a storage.
            # Let's walk through the tree of children to fill the kids list:
            self.append_kids(self.sid_child)

            # Note from OpenOffice documentation: the safest way is to
            # recreate the tree because some implementations may store broken
            # red-black trees...

            # in the OLE file, entries are sorted on (length, name).
            # for convenience, we sort them on name instead:
            # (see __cmp__ method in this class)
            self.kids.sort()


    def append_kids(self, child_sid):
        """
        Walk through red-black tree of children of this directory entry to add
        all of them to the kids list. (recursive method)

        child_sid : index of child directory entry to use, or None when called
                    first time for the root. (only used during recursion)
        """
        #[PL] this method was added to use simple recursion instead of a complex
        # algorithm.
        # if this is not a storage or a leaf of the tree, nothing to do:
        if child_sid == NOSTREAM:
            return
        # check if child SID is in the proper range:
        if child_sid<0 or child_sid>=len(self.olefile.direntries):
            self.olefile._raise_defect(DEFECT_FATAL, 'OLE DirEntry index out of range')
        # get child direntry:
        child = self.olefile._load_direntry(child_sid) #direntries[child_sid]
        debug('append_kids: child_sid=%d - %s - sid_left=%d, sid_right=%d, sid_child=%d'
            % (child.sid, repr(child.name), child.sid_left, child.sid_right, child.sid_child))
        # the directory entries are organized as a red-black tree.
        # (cf. Wikipedia for details)
        # First walk through left side of the tree:
        self.append_kids(child.sid_left)
        # Check if its name is not already used (case-insensitive):
        name_lower = child.name.lower()
        if self.kids_dict.has_key(name_lower):
            self.olefile._raise_defect(DEFECT_INCORRECT,
                "Duplicate filename in OLE storage")
        # Then the child_sid _OleDirectoryEntry object is appended to the
        # kids list and dictionary:
        self.kids.append(child)
        self.kids_dict[name_lower] = child
        # Check if kid was not already referenced in a storage:
        if child.used:
            self.olefile._raise_defect(DEFECT_INCORRECT,
                'OLE Entry referenced more than once')
        child.used = True
        # Finally walk through right side of the tree:
        self.append_kids(child.sid_right)
        # Afterwards build kid's own tree if it's also a storage:
        child.build_storage_tree()


    def __cmp__(self, other):
        "Compare entries by name"
        return cmp(self.name, other.name)
        #TODO: replace by the same function as MS implementation ?
        # (order by name length first, then case-insensitive order)


    def dump(self, tab = 0):
        "Dump this entry, and all its subentries (for debug purposes only)"
        TYPES = ["(invalid)", "(storage)", "(stream)", "(lockbytes)",
                 "(property)", "(root)"]
        print " "*tab + repr(self.name), TYPES[self.entry_type],
        if self.entry_type in (STGTY_STREAM, STGTY_ROOT):
            print self.size, "bytes",
        print
        if self.entry_type in (STGTY_STORAGE, STGTY_ROOT) and self.clsid:
            print " "*tab + "{%s}" % self.clsid

        for kid in self.kids:
            kid.dump(tab + 2)


#--- OleFileIO ----------------------------------------------------------------

class OleFileIO:
    """
    OLE container object

    This class encapsulates the interface to an OLE 2 structured
    storage file.  Use the {@link listdir} and {@link openstream} methods to
    access the contents of this file.

    Object names are given as a list of strings, one for each subentry
    level.  The root entry should be omitted.  For example, the following
    code extracts all image streams from a Microsoft Image Composer file:

        ole = OleFileIO("fan.mic")

        for entry in ole.listdir():
            if entry[1:2] == "Image":
                fin = ole.openstream(entry)
                fout = open(entry[0:1], "wb")
                while 1:
                    s = fin.read(8192)
                    if not s:
                        break
                    fout.write(s)

    You can use the viewer application provided with the Python Imaging
    Library to view the resulting files (which happens to be standard
    TIFF files).
    """

    def __init__(self, filename = None, raise_defects=DEFECT_FATAL):
        """
        Constructor for OleFileIO class.

        filename: file to open.
        raise_defects: minimal level for defects to be raised as exceptions.
        (use DEFECT_FATAL for a typical application, DEFECT_INCORRECT for a
        security-oriented application, see source code for details)
        """
        self._raise_defects_level = raise_defects
        if filename:
            self.open(filename)


    def _raise_defect(self, defect_level, message):
        """
        This method should be called for any defect found during file parsing.
        It may raise an IOError exception according to the minimal level chosen
        for the OleFileIO object.

        defect_level: defect level, possible values are:
            DEFECT_UNSURE    : a case which looks weird, but not sure it's a defect
            DEFECT_POTENTIAL : a potential defect
            DEFECT_INCORRECT : an error according to specifications, but parsing can go on
            DEFECT_FATAL     : an error which cannot be ignored, parsing is impossible
        message: string describing the defect, used with raised exception.
        """
        # added by [PL]
        if defect_level >= self._raise_defects_level:
            raise IOError, message


    def open(self, filename):
        """
        Open an OLE2 file.
        Reads the header, FAT and directory.

        filename: string-like or file-like object
        """
        #[PL] check if filename is a string-like or file-like object:
        # (it is better to check for a read() method)
        if hasattr(filename, 'read'):
            # file-like object
            self.fp = filename
        else:
            # string-like object
            self.fp = open(filename, "rb")
        # old code fails if filename is not a plain string:   
        #if type(filename) == type(""):
        #    self.fp = open(filename, "rb")
        #else:
        #    self.fp = filename

        # lists of streams in FAT and MiniFAT, to detect duplicate references
        # (list of indexes of first sectors of each stream)
        self._used_streams_fat = []
        self._used_streams_minifat = []

        header = self.fp.read(512)

        if len(header) != 512 or header[:8] != MAGIC:
            self._raise_defect(DEFECT_FATAL, "not an OLE2 structured storage file")

        # [PL] header structure according to AAF specifications:
        ##Header
        ##struct StructuredStorageHeader { // [offset from start (bytes), length (bytes)]
        ##BYTE _abSig[8]; // [00H,08] {0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1,
        ##                // 0x1a, 0xe1} for current version
        ##CLSID _clsid;   // [08H,16] reserved must be zero (WriteClassStg/
        ##                // GetClassFile uses root directory class id)
        ##USHORT _uMinorVersion; // [18H,02] minor version of the format: 33 is
        ##                       // written by reference implementation
        ##USHORT _uDllVersion;   // [1AH,02] major version of the dll/format: 3 for
        ##                       // 512-byte sectors, 4 for 4 KB sectors
        ##USHORT _uByteOrder;    // [1CH,02] 0xFFFE: indicates Intel byte-ordering
        ##USHORT _uSectorShift;  // [1EH,02] size of sectors in power-of-two;
        ##                       // typically 9 indicating 512-byte sectors
        ##USHORT _uMiniSectorShift; // [20H,02] size of mini-sectors in power-of-two;
        ##                          // typically 6 indicating 64-byte mini-sectors
        ##USHORT _usReserved; // [22H,02] reserved, must be zero
        ##ULONG _ulReserved1; // [24H,04] reserved, must be zero
        ##FSINDEX _csectDir; // [28H,04] must be zero for 512-byte sectors,
        ##                   // number of SECTs in directory chain for 4 KB
        ##                   // sectors
        ##FSINDEX _csectFat; // [2CH,04] number of SECTs in the FAT chain
        ##SECT _sectDirStart; // [30H,04] first SECT in the directory chain
        ##DFSIGNATURE _signature; // [34H,04] signature used for transactions; must
        ##                        // be zero. The reference implementation
        ##                        // does not support transactions
        ##ULONG _ulMiniSectorCutoff; // [38H,04] maximum size for a mini stream;
        ##                           // typically 4096 bytes
        ##SECT _sectMiniFatStart; // [3CH,04] first SECT in the MiniFAT chain
        ##FSINDEX _csectMiniFat; // [40H,04] number of SECTs in the MiniFAT chain
        ##SECT _sectDifStart; // [44H,04] first SECT in the DIFAT chain
        ##FSINDEX _csectDif; // [48H,04] number of SECTs in the DIFAT chain
        ##SECT _sectFat[109]; // [4CH,436] the SECTs of first 109 FAT sectors
        ##};

        # [PL] header decoding:
        # '<' indicates little-endian byte ordering for Intel (cf. struct module help)
        fmt_header = '<8s16sHHHHHHLLLLLLLLLL'
        header_size = struct.calcsize(fmt_header)
        debug( "fmt_header size = %d, +FAT = %d" % (header_size, header_size + 109*4) )
        header1 = header[:header_size]
        (
            self.Sig,
            self.clsid,
            self.MinorVersion,
            self.DllVersion,
            self.ByteOrder,
            self.SectorShift,
            self.MiniSectorShift,
            self.Reserved, self.Reserved1,
            self.csectDir,
            self.csectFat,
            self.sectDirStart,
            self.signature,
            self.MiniSectorCutoff,
            self.MiniFatStart,
            self.csectMiniFat,
            self.sectDifStart,
            self.csectDif
        ) = struct.unpack(fmt_header, header1)
        debug( struct.unpack(fmt_header,    header1))

        if self.Sig != '\xd0\xcf\x11\xe0\xa1\xb1\x1a\xe1':
            # OLE signature should always be present
            self._raise_defect(DEFECT_FATAL, "incorrect OLE signature")
        if self.clsid != '\x00'*16:
            # according to AAF specs, CLSID should always be zero
            self._raise_defect(DEFECT_INCORRECT, "incorrect CLSID in OLE header")
        debug( "MinorVersion = %d" % self.MinorVersion )
        debug( "DllVersion   = %d" % self.DllVersion )
        if self.DllVersion not in [3, 4]:
            # version 3: usual format, 512 bytes per sector
            # version 4: large format, 4K per sector
            self._raise_defect(DEFECT_INCORRECT, "incorrect DllVersion in OLE header")
        debug( "ByteOrder    = %X" % self.ByteOrder )
        if self.ByteOrder != 0xFFFE:
            # For now only common little-endian documents are handled correctly
            self._raise_defect(DEFECT_FATAL, "incorrect ByteOrder in OLE header")
            # TODO: add big-endian support for documents created on Mac ?
        self.SectorSize = 2**self.SectorShift
        debug( "SectorSize   = %d" % self.SectorSize )
        if self.SectorSize not in [512, 4096]:
            self._raise_defect(DEFECT_INCORRECT, "incorrect SectorSize in OLE header")
        if (self.DllVersion==3 and self.SectorSize!=512) \
        or (self.DllVersion==4 and self.SectorSize!=4096):
            self._raise_defect(DEFECT_INCORRECT, "SectorSize does not match DllVersion in OLE header")
        self.MiniSectorSize = 2**self.MiniSectorShift
        debug( "MiniSectorSize   = %d" % self.MiniSectorSize )
        if self.MiniSectorSize not in [64]:
            self._raise_defect(DEFECT_INCORRECT, "incorrect MiniSectorSize in OLE header")
        if self.Reserved != 0 or self.Reserved1 != 0:
            self._raise_defect(DEFECT_INCORRECT, "incorrect OLE header (non-null reserved bytes)")
        debug( "csectDir     = %d" % self.csectDir )
        if self.SectorSize==512 and self.csectDir!=0:
            self._raise_defect(DEFECT_INCORRECT, "incorrect csectDir in OLE header")
        debug( "csectFat     = %d" % self.csectFat )
        debug( "sectDirStart = %X" % self.sectDirStart )
        debug( "signature    = %d" % self.signature )
        # Signature should be zero, BUT some implementations do not follow this
        # rule => only a potential defect:
        if self.signature != 0:
            self._raise_defect(DEFECT_POTENTIAL, "incorrect OLE header (signature>0)")
        debug( "MiniSectorCutoff = %d" % self.MiniSectorCutoff )
        debug( "MiniFatStart     = %X" % self.MiniFatStart )
        debug( "csectMiniFat     = %d" % self.csectMiniFat )
        debug( "sectDifStart     = %X" % self.sectDifStart )
        debug( "csectDif         = %d" % self.csectDif )

        # calculate the number of sectors in the file
        # (-1 because header doesn't count)
        filesize = os.path.getsize(filename)
        self.nb_sect = ( (filesize + self.SectorSize-1) / self.SectorSize) - 1
        debug( "Number of sectors in the file: %d" % self.nb_sect )

        # file clsid (probably never used, so we don't store it)
        clsid = _clsid(header[8:24])
        self.sectorsize = self.SectorSize #1 << i16(header, 30)
        self.minisectorsize = self.MiniSectorSize  #1 << i16(header, 32)
        self.minisectorcutoff = self.MiniSectorCutoff # i32(header, 56)

        # check known streams for duplicate references (these are always in FAT,
        # never in MiniFAT):
        self._check_duplicate_stream(self.sectDirStart)
        # check MiniFAT only if it is not empty:
        if self.csectMiniFat:
            self._check_duplicate_stream(self.MiniFatStart)
        # check DIFAT only if it is not empty:
        if self.csectDif:
            self._check_duplicate_stream(self.sectDifStart)

        # Load file allocation tables
        self.loadfat(header)
        # Load direcory.  This sets both the direntries list (ordered by sid)
        # and the root (ordered by hierarchy) members.
        self.loaddirectory(self.sectDirStart)#i32(header, 48))
        self.ministream = None
        self.minifatsect = self.MiniFatStart #i32(header, 60)


    def _check_duplicate_stream(self, first_sect, minifat=False):
        """
        Checks if a stream has not been already referenced elsewhere.
        This method should only be called once for each known stream, and only
        if stream size is not null.
        first_sect: index of first sector of the stream in FAT
        minifat: if True, stream is located in the MiniFAT, else in the FAT
        """
        if minifat:
            debug('_check_duplicate_stream: sect=%d in MiniFAT' % first_sect)
            used_streams = self._used_streams_minifat
        else:
            debug('_check_duplicate_stream: sect=%d in FAT' % first_sect)
            # some values can be safely ignored (not a real stream):
            if first_sect in (DIFSECT,FATSECT,ENDOFCHAIN,FREESECT):
                return
            used_streams = self._used_streams_fat
        #TODO: would it be more efficient using a dict or hash values, instead
        #      of a list of long ?
        if first_sect in used_streams:
            self._raise_defect(DEFECT_INCORRECT, 'Stream referenced twice')
        else:
            used_streams.append(first_sect)


    def dumpfat(self, fat, firstindex=0):
        "Displays a part of FAT in human-readable form for debugging purpose"
        # [PL] added only for debug
        if not DEBUG_MODE:
            return
        # dictionary to convert special FAT values in human-readable strings
        VPL=8 # valeurs par ligne (8+1 * 8+1 = 81)
        fatnames = {
            FREESECT:   "..free..",
            ENDOFCHAIN: "[ END. ]",
            FATSECT:    "FATSECT ",
            DIFSECT:    "DIFSECT "
            }
        nbsect = len(fat)
        nlines = (nbsect+VPL-1)/VPL
        print "index",
        for i in range(VPL):
            print ("%8X" % i),
        print ""
        for l in range(nlines):
            index = l*VPL
            print ("%8X:" % (firstindex+index)),
            for i in range(index, index+VPL):
                if i>=nbsect:
                    break
                sect = fat[i]
                if sect in fatnames:
                    nom = fatnames[sect]
                else:
                    if sect == i+1:
                        nom = "    --->"
                    else:
                        nom = "%8X" % sect
                print nom,
            print ""


    def dumpsect(self, sector, firstindex=0):
        "Displays a sector in a human-readable form, for debugging purpose."
        if not DEBUG_MODE:
            return
        VPL=8 # number of values per line (8+1 * 8+1 = 81)
        tab = array.array(UINT32, sector)
        nbsect = len(tab)
        nlines = (nbsect+VPL-1)/VPL
        print "index",
        for i in range(VPL):
            print ("%8X" % i),
        print ""
        for l in range(nlines):
            index = l*VPL
            print ("%8X:" % (firstindex+index)),
            for i in range(index, index+VPL):
                if i>=nbsect:
                    break
                sect = tab[i]
                nom = "%8X" % sect
                print nom,
            print ""

    def sect2array(self, sect):
        """
        convert a sector to an array of 32 bits unsigned integers,
        swapping bytes on big endian CPUs such as PowerPC (old Macs)
        """
        a = array.array(UINT32, sect)
        # if CPU is big endian, swap bytes:
        if sys.byteorder == 'big':
            a.byteswap()
        return a        


    def loadfat_sect(self, sect):
        """
        Adds the indexes of the given sector to the FAT
        sect: string containing the first FAT sector, or array of long integers
        return: index of last FAT sector.
        """
        # a FAT sector is an array of ulong integers.
        if isinstance(sect, array.array):
            # if sect is already an array it is directly used
            fat1 = sect
        else:
            # if it's a raw sector, it is parsed in an array
            fat1 = self.sect2array(sect)
            self.dumpsect(sect)
        # The FAT is a sector chain starting at the first index of itself.
        for isect in fat1:
            #print "isect = %X" % isect
            if isect == ENDOFCHAIN or isect == FREESECT:
                # the end of the sector chain has been reached
                break
            # read the FAT sector
            s = self.getsect(isect)
            # parse it as an array of 32 bits integers, and add it to the
            # global FAT array
            nextfat = self.sect2array(s)
            self.fat = self.fat + nextfat
        return isect


    def loadfat(self, header):
        """
        Load the FAT table.
        """
        # The header contains a sector  numbers
        # for the first 109 FAT sectors.  Additional sectors are
        # described by DIF blocks

        sect = header[76:512]
        debug( "len(sect)=%d, so %d integers" % (len(sect), len(sect)/4) )
        #fat    = []
        # [PL] FAT is an array of 32 bits unsigned ints, it's more effective
        # to use an array than a list in Python.
        # It's initialized as empty first:
        self.fat = array.array(UINT32)
        self.loadfat_sect(sect)
        #self.dumpfat(self.fat)
##      for i in range(0, len(sect), 4):
##          ix = i32(sect, i)
##          #[PL] if ix == -2 or ix == -1: # ix == 0xFFFFFFFEL or ix == 0xFFFFFFFFL:
##          if ix == 0xFFFFFFFEL or ix == 0xFFFFFFFFL:
##              break
##          s = self.getsect(ix)
##          #fat    = fat + map(lambda i, s=s: i32(s, i), range(0, len(s), 4))
##          fat = fat + array.array(UINT32, s)
        if self.csectDif != 0:
            # [PL] There's a DIFAT because file is larger than 6.8MB
            # some checks just in case:
            if self.csectFat <= 109:
                # there must be at least 109 blocks in header and the rest in
                # DIFAT, so number of sectors must be >109.
                self._raise_defect(DEFECT_INCORRECT, 'incorrect DIFAT, not enough sectors')
            if self.sectDifStart >= self.nb_sect:
                # initial DIFAT block index must be valid
                self._raise_defect(DEFECT_FATAL, 'incorrect DIFAT, first index out of range')
            debug( "DIFAT analysis..." )
            # We compute the necessary number of DIFAT sectors :
            # (each DIFAT sector = 127 pointers + 1 towards next DIFAT sector)
            nb_difat = (self.csectFat-109 + 126)/127
            debug( "nb_difat = %d" % nb_difat )
            if self.csectDif != nb_difat:
                raise IOError, 'incorrect DIFAT'
            isect_difat = self.sectDifStart
            for i in xrange(nb_difat):
                debug( "DIFAT block %d, sector %X" % (i, isect_difat) )
                #TODO: check if corresponding FAT SID = DIFSECT
                sector_difat = self.getsect(isect_difat)
                difat = self.sect2array(sector_difat)
                self.dumpsect(sector_difat)
                self.loadfat_sect(difat[:127])
                # last DIFAT pointer is next DIFAT sector:
                isect_difat = difat[127]
                debug( "next DIFAT sector: %X" % isect_difat )
            # checks:
            if isect_difat not in [ENDOFCHAIN, FREESECT]:
                # last DIFAT pointer value must be ENDOFCHAIN or FREESECT
                raise IOError, 'incorrect end of DIFAT'
##          if len(self.fat) != self.csectFat:
##              # FAT should contain csectFat blocks
##              print "FAT length: %d instead of %d" % (len(self.fat), self.csectFat)
##              raise IOError, 'incorrect DIFAT'
        # since FAT is read from fixed-size sectors, it may contain more values
        # than the actual number of sectors in the file.
        # Keep only the relevant sector indexes:
        if len(self.fat) > self.nb_sect:
            debug('len(fat)=%d, shrunk to nb_sect=%d' % (len(self.fat), self.nb_sect))
            self.fat = self.fat[:self.nb_sect]
        debug('\nFAT:')
        self.dumpfat(self.fat)


    def loadminifat(self):
        """
        Load the MiniFAT table.
        """
        # MiniFAT is stored in a standard  sub-stream, pointed to by a header
        # field.
        # NOTE: there are two sizes to take into account for this stream:
        # 1) Stream size is calculated according to the number of sectors
        #    declared in the OLE header. This allocated stream may be more than
        #    needed to store the actual sector indexes.
        # (self.csectMiniFat is the number of sectors of size self.SectorSize)
        stream_size = self.csectMiniFat * self.SectorSize
        # 2) Actually used size is calculated by dividing the MiniStream size
        #    (given by root entry size) by the size of mini sectors, *4 for
        #    32 bits indexes:
        nb_minisectors = (self.root.size + self.MiniSectorSize-1) / self.MiniSectorSize
        used_size = nb_minisectors * 4
        debug('loadminifat(): minifatsect=%d, nb FAT sectors=%d, used_size=%d, stream_size=%d, nb MiniSectors=%d' %
            (self.minifatsect, self.csectMiniFat, used_size, stream_size, nb_minisectors))
        if used_size > stream_size:
            # This is not really a problem, but may indicate a wrong implementation:
            self._raise_defect(DEFECT_INCORRECT, 'OLE MiniStream is larger than MiniFAT')
        # In any case, first read stream_size:
        s = self._open(self.minifatsect, stream_size, force_FAT=True).read()
        #[PL] Old code replaced by an array:
        #self.minifat = map(lambda i, s=s: i32(s, i), range(0, len(s), 4))
        self.minifat = self.sect2array(s)
        # Then shrink the array to used size, to avoid indexes out of MiniStream:
        debug('MiniFAT shrunk from %d to %d sectors' % (len(self.minifat), nb_minisectors))
        self.minifat = self.minifat[:nb_minisectors]
        debug('loadminifat(): len=%d' % len(self.minifat))
        debug('\nMiniFAT:')
        self.dumpfat(self.minifat)

    def getsect(self, sect):
        """
        Read given sector from file on disk.
        sect: sector index
        returns a string containing the sector data.
        """
        # [PL] this original code was wrong when sectors are 4KB instead of
        # 512 bytes:
        #self.fp.seek(512 + self.sectorsize * sect)
        #[PL]: added safety checks:
        #print "getsect(%X)" % sect
        try:
            self.fp.seek(self.sectorsize * (sect+1))
        except:
            debug('getsect(): sect=%X, seek=%d, filesize=%d' %
                (sect, self.sectorsize*(sect+1), os.path.getsize(self.fp.name)))
            self._raise_defect(DEFECT_FATAL, 'OLE sector index out of range')
        sector = self.fp.read(self.sectorsize)
        if len(sector) != self.sectorsize:
            debug('getsect(): sect=%X, read=%d, sectorsize=%d' %
                (sect, len(sector), self.sectorsize))
            self._raise_defect(DEFECT_FATAL, 'incomplete OLE sector')
        return sector


    def loaddirectory(self, sect):
        """
        Load the directory.
        sect: sector index of directory stream.
        """
        # The directory is  stored in a standard
        # substream, independent of its size.

        # open directory stream as a read-only file:
        # (stream size is not known in advance)
        self.directory_fp = self._open(sect)

        #[PL] to detect malformed documents and avoid DoS attacks, the maximum
        # number of directory entries can be calculated:
        max_entries = self.directory_fp.size / 128
        debug('loaddirectory: size=%d, max_entries=%d' %
            (self.directory_fp.size, max_entries))

        # Create list of directory entries
        #self.direntries = []
        # We start with a list of "None" object
        self.direntries = [None] * max_entries
##        for sid in xrange(max_entries):
##            entry = fp.read(128)
##            if not entry:
##                break
##            self.direntries.append(_OleDirectoryEntry(entry, sid, self))
        # load root entry:
        root_entry = self._load_direntry(0)
        # Root entry is the first entry:
        self.root = self.direntries[0]
        # read and build all storage trees, starting from the root:
        self.root.build_storage_tree()


    def _load_direntry (self, sid):
        """
        Load a directory entry from the directory.
        This method should only be called once for each storage/stream when
        loading the directory.
        sid: index of storage/stream in the directory.
        return: a _OleDirectoryEntry object
        raise: IOError if the entry has always been referenced.
        """
        # check if SID is OK:
        if sid<0 or sid>=len(self.direntries):
            self._raise_defect(DEFECT_FATAL, "OLE directory index out of range")
        # check if entry was already referenced:
        if self.direntries[sid] is not None:
            self._raise_defect(DEFECT_INCORRECT,
                "double reference for OLE stream/storage")
            # if exception not raised, return the object
            return self.direntries[sid]
        self.directory_fp.seek(sid * 128)
        entry = self.directory_fp.read(128)
        self.direntries[sid] = _OleDirectoryEntry(entry, sid, self)
        return self.direntries[sid]


    def dumpdirectory(self):
        """
        Dump directory (for debugging only)
        """
        self.root.dump()


    def _open(self, start, size = 0x7FFFFFFF, force_FAT=False):
        """
        Open a stream, either in FAT or MiniFAT according to its size.
        (openstream helper)

        start: index of first sector
        size: size of stream (or nothing if size is unknown)
        force_FAT: if False (default), stream will be opened in FAT or MiniFAT
                   according to size. If True, it will always be opened in FAT.
        """
        debug('OleFileIO.open(): sect=%d, size=%d, force_FAT=%s' %
            (start, size, str(force_FAT)))
        # stream size is compared to the MiniSectorCutoff threshold:
        if size < self.minisectorcutoff and not force_FAT:
            # ministream object
            if not self.ministream:
                # load MiniFAT if it wasn't already done:
                self.loadminifat()
                # The first sector index of the miniFAT stream is stored in the
                # root directory entry:
                size_ministream = self.root.size
                debug('Opening MiniStream: sect=%d, size=%d' %
                    (self.root.isectStart, size_ministream))
                self.ministream = self._open(self.root.isectStart,
                    size_ministream, force_FAT=True)
            return _OleStream(self.ministream, start, size, 0,
                              self.minisectorsize, self.minifat)
        else:
            # standard stream
            return _OleStream(self.fp, start, size, 512,
                              self.sectorsize, self.fat)


    def _list(self, files, prefix, node):
        """
        (listdir helper)
        files: list of files to fill in
        prefix: current location in storage tree (list of names)
        node: current node (_OleDirectoryEntry object)
        """
        prefix = prefix + [node.name]
        for entry in node.kids:
            if entry.kids:
                self._list(files, prefix, entry)
            else:
                files.append(prefix[1:] + [entry.name])


    def listdir(self):
        """
        Return a list of streams stored in this file
        """
        files = []
        self._list(files, [], self.root)
        return files


    def _find(self, filename):
        """
        Returns directory entry of given filename. (openstream helper)
        Note: this method is case-insensitive.

        filename: path of stream in storage tree (except root entry), either:
            - a string using Unix path syntax, for example:
              'storage_1/storage_1.2/stream'
            - a list of storage filenames, path to the desired stream/storage.
              Example: ['storage_1', 'storage_1.2', 'stream']
        return: sid of requested filename
        raise IOError if file not found
        """

        # if filename is a string instead of a list, split it on slashes to
        # convert to a list:
        if isinstance(filename, basestring):
            filename = filename.split('/')
        # walk across storage tree, following given path:
        node = self.root
        for name in filename:
            for kid in node.kids:
                if kid.name.lower() == name.lower():
                    break
            else:
                raise IOError, "file not found"
            node = kid
        return node.sid


    def openstream(self, filename):
        """
        Open a stream as a read-only file object (StringIO).

        filename: path of stream in storage tree (except root entry), either:
            - a string using Unix path syntax, for example:
              'storage_1/storage_1.2/stream'
            - a list of storage filenames, path to the desired stream/storage.
              Example: ['storage_1', 'storage_1.2', 'stream']
        return: file object (read-only)
        raise IOError if filename not found, or if this is not a stream.
        """
        sid = self._find(filename)
        entry = self.direntries[sid]
        if entry.entry_type != STGTY_STREAM:
            raise IOError, "this file is not a stream"
        return self._open(entry.isectStart, entry.size)


    def get_type(self, filename):
        """
        Test if given filename exists as a stream or a storage in the OLE
        container, and return its type.

        filename: path of stream in storage tree. (see openstream for syntax)
        return: False if object does not exist, its entry type (>0) otherwise:
            - STGTY_STREAM: a stream
            - STGTY_STORAGE: a storage
            - STGTY_ROOT: the root entry
        """
        try:
            sid = self._find(filename)
            entry = self.direntries[sid]
            return entry.entry_type
        except:
            return False


    def exists(self, filename):
        """
        Test if given filename exists as a stream or a storage in the OLE
        container.

        filename: path of stream in storage tree. (see openstream for syntax)
        return: True if object exist, else False.
        """
        try:
            sid = self._find(filename)
            return True
        except:
            return False


    def get_size(self, filename):
        """
        Return size of a stream in the OLE container, in bytes.

        filename: path of stream in storage tree (see openstream for syntax)
        return: size in bytes (long integer)
        raise: IOError if file not found, TypeError if this is not a stream.
        """
        sid = self._find(filename)
        entry = self.direntries[sid]
        if entry.entry_type != STGTY_STREAM:
            #TODO: Should it return zero instead of raising an exception ?
            raise TypeError, 'object is not an OLE stream'
        return entry.size


    def get_rootentry_name(self):
        """
        Return root entry name. Should usually be 'Root Entry' or 'R' in most
        implementations.
        """
        return self.root.name


    def getproperties(self, filename):
        """
        Return properties described in substream.

        filename: path of stream in storage tree (see openstream for syntax)
        return: a dictionary of values indexed by id (integer)
        """
        fp = self.openstream(filename)

        data = {}

        # header
        s = fp.read(28)
        clsid = _clsid(s[8:24])

        # format id
        s = fp.read(20)
        fmtid = _clsid(s[:16])
        fp.seek(i32(s, 16))

        # get section
        s = "****" + fp.read(i32(fp.read(4))-4)

        for i in range(i32(s, 4)):

            id = i32(s, 8+i*8)
            offset = i32(s, 12+i*8)
            type = i32(s, offset)

            debug ('property id=%d: type=%d offset=%X' % (id, type, offset))

            # test for common types first (should perhaps use
            # a dictionary instead?)

            if type == VT_I2:
                value = i16(s, offset+4)
                if value >= 32768:
                    value = value - 65536
            elif type == VT_UI2:
                value = i16(s, offset+4)
            elif type in (VT_I4, VT_ERROR):
                value = i32(s, offset+4)
            elif type == VT_UI4:
                value = i32(s, offset+4) # FIXME
            elif type in (VT_BSTR, VT_LPSTR):
                count = i32(s, offset+4)
                value = s[offset+8:offset+8+count-1]
            elif type == VT_BLOB:
                count = i32(s, offset+4)
                value = s[offset+8:offset+8+count]
            elif type == VT_LPWSTR:
                count = i32(s, offset+4)
                value = self._unicode(s[offset+8:offset+8+count*2])
            elif type == VT_FILETIME:
                value = long(i32(s, offset+4)) + (long(i32(s, offset+8))<<32)
                # FIXME: this is a 64-bit int: "number of 100ns periods
                # since Jan 1,1601".  Should map this to Python time
                value = value / 10000000L # seconds
            elif type == VT_UI1:
                value = ord(s[offset+4])
            elif type == VT_CLSID:
                value = _clsid(s[offset+4:offset+20])
            elif type == VT_CF:
                count = i32(s, offset+4)
                value = s[offset+8:offset+8+count]
            else:
                value = None # everything else yields "None"

            # FIXME: add support for VT_VECTOR

            #print "%08x" % id, repr(value),
            #print "(%s)" % VT[i32(s, offset) & 0xFFF]

            data[id] = value

        return data

#
# --------------------------------------------------------------------
# This script can be used to dump the directory of any OLE2 structured
# storage file.

if __name__ == "__main__":

    import sys

    # [PL] display quick usage info if launched from command-line
    if len(sys.argv) <= 1:
        print __doc__
        print """
Launched from command line, this script parses OLE files and prints info.

Usage: OleFileIO_PL.py [-d] [-c] <file> [file2 ...]

Options:
-d : debug mode (display a lot of debug information, for developers only)
-c : check all streams (for debugging purposes)
"""
        sys.exit()

    check_streams = False
    for filename in sys.argv[1:]:
##      try:
            # OPTIONS:
            if filename == '-d':
                # option to switch debug mode on:
                set_debug_mode(True)
                continue
            if filename == '-c':
                # option to switch check streams mode on:
                check_streams = True
                continue

            ole = OleFileIO(filename, raise_defects=DEFECT_INCORRECT)
            print "-" * 68
            print filename
            print "-" * 68
            ole.dumpdirectory()
            for streamname in ole.listdir():
                if streamname[-1][0] == "\005":
                    print streamname, ": properties"
                    props = ole.getproperties(streamname)
                    props = props.items()
                    props.sort()
                    for k, v in props:
                        #[PL]: avoid to display too large or binary values:
                        if isinstance(v, basestring):
                            if len(v) > 50:
                                v = v[:50]
                            # quick and dirty binary check:
                            for c in (1,2,3,4,5,6,7,11,12,14,15,16,17,18,19,20,
                                21,22,23,24,25,26,27,28,29,30,31):
                                if chr(c) in v:
                                    v = '(binary data)'
                                    break
                        print "   ", k, v

            if check_streams:
                # Read all streams to check if there are errors:
                print '\nChecking streams...'
                for streamname in ole.listdir():
                    # print name using repr() to convert binary chars to \xNN:
                    print '-', repr('/'.join(streamname)),'-',
                    st_type = ole.get_type(streamname)
                    if st_type == STGTY_STREAM:
                        print 'size %d' % ole.get_size(streamname)
                        # just try to read stream in memory:
                        ole.openstream(streamname)
                    else:
                        print 'NOT a stream : type=%d' % st_type
                print ''

            #[PL] Test a few new methods:
            root = ole.get_rootentry_name()
            print 'Root entry name: "%s"' % root
            if ole.exists('worddocument'):
                print "This is a Word document."
                print "type of stream 'WordDocument':", ole.get_type('worddocument')
                print "size :", ole.get_size('worddocument')
                if ole.exists('macros/vba'):
                    print "This document may contain VBA macros."
##      except IOError, v:
##          print "***", "cannot read", file, "-", v