chmlib is a small library designed for accessing MS ITSS files. The ITSS file
format is used for Microsoft Html Help files (.chm), which have been the
predominant medium for software documentation from Microsoft during the past
several years, having superceded the previously used .hlp file format.
Note that this is NOT the same as the OLE structured storage file format used
by MS Excel, Word, and so on. Instead, it is a different file format which
fulfills a similar purpose. Both file formats may be accessed via instances
of the IStorage COM interface, which is essentially an "acts like a
FILE FORMAT SUPPORT
Lookup of files in the archive is supported, and should be relatively quick.
Reading of files in the archive is also supported.
Writing is not supported, but may be added in the future.
In terms of support for the ITSS file format, there are a few places in which
the support provided by this library is not fully general:
1. ITSS files whose names contain UTF-8 characters which are not part of the
ASCII subset will not currently be dealt with gracefully. Currently, the
filenames are not converted from UTF-8, but are instead returned as-is. I'm
very interested in hearing any suggestions as to the "right" way to handle
2. Only version 3 ITSS files are supported at present, though some work has
gone towards divining the differences between different versions of the
file format. It is possible that version 2 ITSS files might work properly
with this library, but unconfirmed.
3. Archives larger than 4 GB should be supported just fine, but if they
contain files larger than 4GB, this library may break. Fortunately, this
seems somewhat unlikely.
If you run into .chm files (or files you suspect are ITSS files) that this
library doesn't work with, please contact me so I can fix the library.
This software was originally developed on a Intel x86 Debian Linux machine,
using gcc 3.0. It has since been compiled on various flavors of RedHat as
well, and using versions of gcc from 2.95 through 3.2. Basic Win32 support
should be in this release. (While a port to Win32 may _seem_ like a funny
idea, given that Windows ships with libraries for CHM access, it turns out that
Win CE does not; I've gotten a request for a port to Windows CE.)
Chmlib apparently works on OS X, with some tweaks. In particular, disabling
pread and io64 apparently works.
Finally, Andrew Hodgetts has ported to Solaris and IRIX:
On Monday, 7 Oct 2002, Andrew Hodgetts wrote:
> I used both SunProC and GCC on the solaris machines to compile. They
> both worked ok.
> However, both required -lsocket on the link line of the Makefile or you
> recieve linking errors.
> I have this working on CPUs ranging from Sun4m (Sparc5) through to
> UltraSparcIII (SunFireV880).
> Irix (SGI):
> I only testing with the MIPS compiler (not GCC). All worked ok - lots of
> warning messages, but it always does that.
He further noted that:
> ... for NON GCC compilers, a little tweaking may be required, but nothing too
> complex. ie SunProC doesn't understand -fPIC for library building. Irix
> required -n32 (new 32bit libraries) etc. These are things that someone who
> uses the OS and compiler should be used to dealing with.
* Stuart Caie: the LZX decompression code, and for granting permission to
re-license under the LGPL.
* Sven Tantau: identification of a stack-overflow security flaw and a quick fix
for the problem; identification of a possible security danger in the example
* iDEFENSE Labs: identification of a nasty stack-overflow security flaw
* Palasik Sandor: identification of a potential security flaw in lzx.c as well
as a quick fix for the problem
* David Huseby: An excellent patch to the chm_enumerate functionality, relating
to the "what" flags, which didn't work entirely correctly before
* Vadim Zeitlin: Configure script cleanup, including an important update to
allow detection of platforms where pread64 doesn't work. (OS X)
* Vitaly V. Bursov: Compilation on x86-64.
* mc: A suggestion to add a "mkdir" to the install step.
* Stan Tobias: bugfixes and the added 'index page' feature of chm_http.
* Andrew Hodgetts: porting to Solaris and IRIX, as well as fixing some
little-endian biases in the code.
* Rich Erwin: Windows CE support.
* Pabs: bug fixes and suggestions.
* Antony Dovgal: setting up autoconf/automake based build process.
* Ragnar Hojland Espinosa: patches to make chm_http more useful.
* Razvan Cojocaru: forwarding along information regarding building on OS X.
* Julien Lemoine: creating and maintaining the Debian package of chmlib.
* Prarit Bhargava: Compilation on ia64
* Jean-Marc Vanel: elimination of compilation warnings in extract_chmLib
* Sisyphus & Matej Spiller-Muys: Compilation under MinGW32
* Kyle Davenport: helper script for using chm_http with mozilla
* Matthew Daniel & Mark Rosenstand: help to sort out issues with the build
* Anyone else I've forgotten. (?)