LZMA shared library for Atari (MiNT/MagiC)
=================================================

This is an attempt to make LZMA, which is used widely by several applications,
available as a shared libary for Atari.

The goal here was to make it as easy as possible to switch from linking a
static version, to use the shared version instead. Remember though that
neither the OS nor the compilers in use have direct support for that,
and that the application needs to support it.


How to use it:
==============

for GCC:
Install the header files from the include directory to /usr/include (or
to your cross installation directory), the libraries to /usr/lib, and
the executables from /mint/slb to a directory where Slbopen can find them
(usually also /mint/slb, or c:/gemsys/slb)

In your application:
- Define -DLZMA_SLB before including lzma.h, or include slb/lzma.h instead
  (both should have the same effect)
- add a call to slb_lzma_open() before using any function from lzma. Optionally,
  you can pass in a library search path that is passed along to Slbopen().
- for completeness, you can also add a call to slb_lzma_close() before your
  application terminates.
- link to liblzma.slb.a instead of the normal liblzma.a
- use any function from LZMA as usual. No need to pass any extra parameters.

For Pure-C:
Same as for GCC, except:
- You can use the header files from the purec/include directory instead. They
  are identical to the ones for GCC, just converted to have CR/LF endings.
- the static library is named lzma.lib, the import library for the
  shared library is lzmaslb.lib.

Note that some of the header files in the lzma directory have been renamed to
fit the 8.3 TOS format, but you usually don't have to care about that,
since they are automatically included by <lzma.h>.

No matter whether using the static or the shared library, you may have
to increase the stack size of your application. For gcc, this may be
achieved either by passing -Wl,-stack,256k in the link command, or by
defining a global (long) _stacksize variable in your program. A stacksize
of at least 256k is recommended (at least that was enough to run the
test programs), maybe you need even more.

Also note that the LZMA compressors/decompressors are quite memory intensive.

That's all!

Note that slb_lzma_open() contains fallback code for systems lacking Slbopen(),
so this should work even on SingleTOS.



Files in the archive:
=====================

usr/include/lzma.h
usr/include/lzma/*.h
    Slightly modified versions from the files of the XZ distribution,
    intended to be usable for both static and shared linking.
usr/include/slb/lzma.h
    Include file for using the shared library, with declarations of the above
    mentioned functions.
usr/lib/liblzma.a
    Static version of the library
usr/lib/liblzma.slb.a
    Import library for using the shared library instead
usr/lib/m68020-60/liblzma.a
    Static version of the library, compiled for 68020 or better
usr/lib/m68020-60/liblzma.slb.a
    Import library for using the shared library instead,
    compiled for 68020 or better
usr/lib/m5475/liblzma.a
    Static version of the library, compiled for coldfire
usr/lib/m5475/liblzma.slb.a
    Import library for using the shared library instead,
    compiled for coldfire
usr/bin/*
    
    The command tools xz, xzdec etc. from the original distribution,
    recompiled for using the shared library instead.

mint/slb
    The shared library itself. Use the one appropiate for your system.


Exported functions:
===================

#0: long lzma_slb_control(long fn, void *arg)
    - used internally by slb_lzma_open() to check that
      the correct version of the library was loaded

everything else:
    - all functions publicitly available from lzma.h.
      Consult that header file, or the man page on
      how to use them.


Known bugs:
===========

- Although the handle of the shared library and its corresponding exec
  function are available to the application, the exec function
  should not be directly called. Always use the import functions
  (they cover all available functions, anyway).

- When using the library with Pure-C, you may have to change some variables
  from plain "int" to "lzma_int_t". This is because the library was
  compiled by gcc, and sizeof(int) differs between the two.

- due to lack of support from the OS, files >= 4GiB cannot be handled
