########################################################################
##
## Copyright (C) 2012-2025 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## 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 3 of the License, or
## (at your option) any later version.
##
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## 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, see
## <https://www.gnu.org/licenses/>.
##
########################################################################

## -*- texinfo -*-
## @deftypefn {} {@var{filterspec} =} __fltk_file_filter__ (@var{file_filter})
## Undocumented internal function.
## @end deftypefn

function retval = __fltk_file_filter__ (file_filter)

  retval = "";
  [r, c] = size (file_filter);
  if ((c == 0) || (c > 2))
    error ("file FILTER cell must have 1 or 2 columns");
  endif
  fltk_str = "";
  for idx = 1 : r

    curr_ext = file_filter{idx, 1};
    curr_ext = ostrsplit (curr_ext, ";");

    if (length (curr_ext) > 1)
      curr_ext = strrep (curr_ext, '*.', ',');
      curr_ext = strcat (curr_ext{:})(2 : end);
      curr_ext = strcat ("*.{", curr_ext, "}");
    else
      curr_ext = curr_ext{:};
    endif

    curr_desc = strcat (curr_ext(3:end), "-Files");

    if (c == 2)
      curr_desc = file_filter{idx, 2};
      curr_desc = strrep (curr_desc, '(', '<');
      curr_desc = strrep (curr_desc, ')', '>');
    endif

    if (length (fltk_str) > 0)
      fltk_str = strcat (fltk_str, "\t", curr_desc, " (", curr_ext, ")");
    else
      fltk_str = strcat (curr_desc, " (", curr_ext, ")");
    endif

  endfor
  retval = fltk_str;

endfunction
