A major drawback of the system is (well, _I_ find it a major drawback anyway) that it only works on Windows, thereby denying users of other operating systems to play and create ADRIFT games. (yes, I tried wine but I couldn't get it to work) This web page is meant to facilitate the development of software that deals with ADRIFT games on 'alternative' operating systems. Imagine to be able to take an ADRIFT game with you on your PDA, for example.
The information in this site is not directed towards the average ADRIFT users, but to developers willing to write ADRIFT programs or reverse engineer ADRIFT files. Non technical users of other operating systems may, in the future, check under 'Free Software' to find a list of ADRIFT programs for their OS.
salvage.c. Being able to
decrypt ADRIFT files is needed in order to write an interpreter (runner) and it
will also enable to reverse engineer the format further.
The structure (after deobfuscation) of a .TAF file (versions
3.80, 3.90, 4.00) is detailed in taf.spec.
It is a human/machine readable file from which all kinds of useful programs can
be generated. The .spec file is in the public domain. As an
example I present an old version of version390.h; it is generated from
taf.spec and under the GNU GPL.
All my code for dealing with .TAF files is currently in a
subversion repository. The code is in pre-alpha state; it can be used for
almost nothing. The repository can be browsed using the viewvc
script on my server. Also, there public read-only access to the repository. If
you have installed subversion, the source can be checked out by typing
svn checkout http://penta.snel.it/svn/libadrift/trunk libadrift.
This command will create a directory libadrift/ in the current
directory and populate it with files. The library and examples can be built by
cd libadrift; ./autogen.sh && make. Some examples are
provided in the examples/ subdirectory of libadrift/.
There is NO SUPPORT and you are free to do with this code what you want, as
long as you abide by the terms of the GNU General Public License v2.
For the build to succeed, you need automake-1.6 (or 1.7) and flex-2.5.31 (or
possibly, any later version). For the people without these development tools (or svn),
I have a recent snapshot (revision 477) of libadrift here, build it with
./configure && make, then look at the examples in the directories
examples/ and guitest/. This is only a development pre-alpha release, I am not interested
in patches (unless they adhere to my coding style and are trivial or very good) and bugreports.
I present a futile attempt at documentation, see the README of libadrift.
Q: I don't know what to do with salvage.c (can't compile,
doesn't work, whatever..).
A: Please learn C and learn to use a compiler. Software that is meant for
use by the general public should appear in the Free Software section of this
page.
Q: How did you reverse engineer the encryption.
A: Knowledge of basic encryption methods, a modest amount of foresight,
knowledge of machine language/assembler and the inclusion of
zlibtool.ocx was a big hint about the compression algorithm used
in ADRIFT 4.00.
Q: Isn't reverse engineering illegal?
A: No. Please see Article 5 section 3 of the European Union Directive
'Software Copyright Protection' of the 14th of May 1991. It basically says:
'You don't need permission of the copyright holder of a progam to look under
the hood and discover its algorithms.' Even laws like the DMCA allow reverse
engineering to gain interoperability. Note that the copyright holder in Europe
cannot own the algorithms in his/her code, that would require sofware patent
laws.
Q: I am an ADRIFT author and I dislike you giving information to people
accessing the text in MY game.
A: You released the game for people to play and enjoy it, right? Disclosing
this information enables people to write runners and converters for ADRIFT
games on other operating systems that Windows alone. This means that you will
get a larger audience for your game. Note that other major text adventure
languages (TADS, Inform) also have decompilers and multiple interpreters
(runners) and that users of that languages also are not immune cheating players
and viewing the game text.
Q: I want to be able to release a game so that people only can play it. It
should be impossible for people to look at my game from a developer's point of
view. I would be disastrous if other authors would be able to learn from my
games and make their future games better.
A: Well, it is possible, in principle: 'Protecting' a game in a way you
would like involves running the game on a trusted central server and letting
the players connect to that server through some web interface.
Q: m33 1337 h4X0r, J00 7311 P4ZZ 70 m33? (How can I get the password from a
.TAF file?)
A: Discovering the way the password is stored in .TAF files is
not rocket science, but I find it inappropriate and unneeded to release that
information. If you really need it for your ADRIFT application then you should
figure it out for yourself. If you do find out how the password is stored, use
that information at your own discretion, but bear in mind that some authors of
ADRIFT games probably assumed that the password was unbreakable and they will
probably not very happy about you creating password erasers/displayers.
There are currently two Free Software projects that deal with ADRIFT files:
jAsea, an ADRIFT runner in Java,
SCARE, like the other one, but written in C.
If you write free other software, you may submit a link to me and I will put it here.
Last significantly updated: July 19, 2004.