## Copyright (C) 1996, 2000, 2005, 2007
##               Auburn University.  All rights reserved.
##
## 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.
##
## 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, see
## <http://www.gnu.org/licenses/>.

## Undocumented internal function.

## -*- texinfo -*-
## @deftypefn {Function File} {} __syschnamesl__ (@var{olist}, @var{old_names}, @var{inames}, @var{listname})
## used internally in syschnames
## item olist: index list
## old_names: original list names
## inames: new names
## listname: name of index list
##
## combines the two string lists old_names and inames
## @end deftypefn

function old_names = __syschnamesl__ (olist, old_names, inames, listname)

  probstr = [];
  if( max(olist) > rows(old_names) )
    probstr = ["index list value(s) exceed(s) number of signals (", ...
      num2str(rows(old_names)),")"];

  elseif( length(olist) > rows(inames) )
    probstr = ["index list dimension exceeds number of replacement names (", ...
      num2str(rows(inames)),")"];

  elseif(isempty(olist))
    probstr = [];    # do nothing, no changes

  elseif(min(size(olist)) != 1 )
    probstr = "index list must be either a vector or an empty matrix";

  elseif(max(olist) > rows(old_names))
    probstr = ["max(",listname,")=",num2str(max(olist))," > ", ...
        num2str(rows(old_names)),", too big"];

  elseif(min(olist) < 1)
    probstr = ["min(",listname,")=",num2str(min(olist))," < 1, too small"];

  else
    if( length(olist)  == 1)
        len_in = columns(inames);
        len_out = columns(old_names);

      if (len_in < len_out)
        inames(1,(len_in+1):(len_out)) = zeros(1,(len_out - len_in));
      endif

      old_names(olist,1:length(inames)) = inames;
    elseif(length(olist) > 1)
      for ii=1:length(olist)
        mystr = inames(ii,:);
        len_my = columns(mystr);
        len_out = columns(old_names);

        if (len_my < len_out)
          mystr(1,(len_my+1):(len_out)) = " "*ones(1,(len_out - len_my));
          len_my = len_out;
        endif

        old_names(olist(ii),1:len_my) = mystr;
      endfor
    endif
  endif
  if(!isempty(probstr))
    ## the following lines are NOT debugging code!
    disp("Problem in syschnames: old names are")
    __outlist__(old_names," ")
    disp("new names are")
    __outlist__(inames,"    ")
    disp("list indices are")
    disp(olist)
    error(sprintf("syschnames: \"%s\" dim=(%d x %d)--\n\t%s\n", ...
        listname, rows(olist), columns(olist),probstr));
  endif

  ## change zeros  to blanks
  if( find(old_names == 0) )
    ## disp("__syschnamesl__: old_names contains zeros ")
    ## old_names
    ## disp("/__syschnamesl__");

    [ii,jj] = find(old_names == 0);
    for idx=1:length(ii)
      old_names(ii(idx),jj(idx)) = " ";
    endfor

    ## disp("__syschnamesl__: old_names fixed zeros ")
    ## old_names
    ## disp("/__syschnamesl__");
  endif

  ## just in case it's not a string anymore
  if( !ischar(old_names) )
    old_names = char(old_names);
  endif

  ## disp("__syschnamesl__: exit, old_names=")
  ## old_names
  ## disp("/__syschnamesl__: exiting")

endfunction