decompress any compressed type

[Bill Denney]

There have been several requests recently to have the package manager 
handle arbitrary compressed types.  While I've not implemented all of 
the features required for this in the associated functions, here is 
decompress.m that takes the same arguments as any of the other 
decompression routines, but it will just choose the right one based on 
file extension.

Eventually, we may want to move all the decompression code to within 
this function and have the others just call it (so that everything 
correctly does unwind_protect, changing directories, etc. without having 
essentially duplicated code).  John, if you'd like that, I can probably 
work on it tomorrow.

I chose the name decompress instead of uncompress because uncompress is 
the unix command that specifically expands .Z files.

Bill

scripts/ChangeLog:

2006-10-17  Bill Denney  <address@hidden>
   * miscellaneous/decompress.m: new function, decompress any file 
based on its extension
## Copyright (C) 2005 Bill Denney
## 
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2, or (at your option)
## any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, write to the Free
## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
## 02110-1301, USA.

## -*- texinfo -*-
## @deftypefn {Function File} decompress (@var{file}, @var{dir})
## Unpack the archive @var{file} based on its extension to the directory
## @var{dir}.  If @var{file} is a cellstr, then all files will be
## handled individually.  If @var{dir} is not specified, it defaults to
## the current directory.
## @seealso{tar, untar, gzip, gunzip, zip, unzip}
## @end deftypefn

## Author: Bill Denney <address@hidden>

function files = decompress (file, directory)

  if (nargin == 1 || nargin == 2)

    if (nargin == 1)
      directory = ".";
    endif

    if ischar (file)
      [pathstr, name, ext] = fullfile (file);

      ## check to see if it's .tar.gz, .tar.Z, or .tar.bz2
      if strcmp (ext, ".gz") || strcmp (ext, ".Z") || strcmp (ext, ".bz2")
        [tmppathstr, tmpname, tmpext] = fullfile (name);
        if strcmp(tmpext, ".tar")
          name = tmpname;
          ext = [tmpext ext];
        endif
      endif

    elseif iscellstr (file)
      files = {};
      for i = 1:numel (file)
        tmpfiles = decompress (file{i}, directory);
        files = {files{:} tmpfiles{:}};
      endfor

    else
      error ("decompress: invalid input file class, %s", class(file));
    endif

    switch lower(ext)
      case {".gz" ".Z"}
        files = gunzip (file, directory);
      case {".tar" ".tar.gz" ".tgz" ".tar.Z"}
        files = untar (file, directory);
      case {".zip"}
        files = unzip (file, directory);
      ## case {".bz2"}
      ##   files = bunzip2 (file, directory);
      otherwise
        error ("decompress: unrecognised file type, %s", ext);
    endswitch

  else
    print_usage ();
  endif

endfunction