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<section> <date> 19. Aug 2001 </date>
<h2> SDL rwops </h2> Example to make an SDL_rwops interface.
<p><small> some <b>MSVC</b> help in
<a href="README.MSVC6">README.MSVC6</a> and
<a href="README.SDL">README.SDL</a>
</small></p>
<!--border-->
<section>
<h3> Source </h3>
<P>
The example sources of the <a href="zziplib.html">zziplib library</a>
are usually put under the <a href="COPYING.ZLIB">ZLIB license</a> so
that you can reuse the code freely in your own projects. Here we talk
about the example that might be most useful for
<a href="http://libsdl.org">SDL</a> based programs.
Just copy the two files
<a href="SDL_rwops_zzip.h">SDL_rwops_zzip.h</a>
and
<a href="SDL_rwops_zzip.c">SDL_rwops_zzip.c</a>
to the directory with your other project sources, and make sure
to link it somehow to your programs. I did not make the effort to
create a separate library out of it - it would just export one
single function <tt>SDL_RWFromZZIP</tt> that has the same call-synopsis
like <tt>SDL_RWFromFile</tt> (but it can not (yet) write a zip-file).
</P>
<P>
The source file <a href="SDL_rwops_zzip.c">SDL_rwops_zzip.c</a> is
quite short - it just stores a ZZIP_FILE handle in the userdata
field of the <tt>SDL_rwops</tt> structure. The SDL'rwop calls will then
fetch that pointer and call the corresponding functions from the
<a href="zziplib.html">zziplib library</a>. Most of the glue code
is in the <tt>SDL_RWFromZZIP</tt> function that allocates an
<tt>SDL_rwops</tt> structure and fills the handler-functions
into the callback fields.
</P>
</section><section>
<h3> Usage </h3>
<P>
If you link this file to your project, remember that your executables
do now have additional dependencies - not only -lzzip to link with
the <a href="zziplib.html">zziplib library</a> - do not forget to
link with zlib library via -lz. Of course, there is a lib-config
script that you can use: `zzip-config --libs` will return these
linker-infos (unless you have a native-windows system - it is
shell-script).
</P>
<P>
As an example, replace that <tt>SDL_RWFromFile</tt> that accesses your
game-graphic files - these files are stored in shared/myapp
of course where they belong. When you've done that
then go to X/share/myapp and
<br><code>
`(cd graphics/ && zip -9r ../graphics.zip .)` </code><br>
and rename the graphics/ subfolder - and still all your files
are found: a filepath like X/shared/graphics/game/greetings.bmp
will open X/shared/graphics.zip and return the zipped file
game/greetings.bmp in the zip-archive (for reading that is).
</P>
</section><section>
<h3> Test </h3>
<P>
The <a href="zziplib.html">zziplib</a> configure script does not
look for <a href="http://libsdl.org">SDL</a>. If you know that
you have <a href="http://libsdl.org">SDL</a> installed
then you can check this <tt>SDL_rwops</tt> example by using
<code><nobr>`make testsdl`</nobr></code>. This will compile the
two source files <a href="SDL_rwops_zzip.c">SDL_rwops_zzip.c</a>
and <a href="SDL_rwops_zzcat.c">SDL_rwops_zzcat.c</a> to be linked
together into an executable called <code>zzcatsdl</code>. The test
will continue with a <code><nobr>`zzcatsdl test/README`</nobr></code>
- just like it is done for <code><nobr>`make test3`</nobr></code>.
</P>
<P>
The corresponding section in the <a href="Makefile.am">Makefile.am</a>
is also an example how to use lib-config scripts to build files. Here
there is no build-processing that had been tweaked much by automake/autoconf.
Just use sdl-config and zzip-config to add the needed flags.
</P>
</section></section>
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