# HG changeset patch
# User Ben Abbott <bpabbott@mac.com>
# Date 1237654198 14400
# Node ID b3268a0458f23fa19ec384773bee12b4724305c1
# Parent  cc916241e811e37187e85ff60006364699f5caac
__gnuplot_get_var__.m: Add function to get gnuplot variables.

diff -r cc916241e811 -r b3268a0458f2 scripts/ChangeLog
--- a/scripts/ChangeLog	Sat Mar 21 09:35:35 2009 -0400
+++ b/scripts/ChangeLog	Sat Mar 21 12:49:58 2009 -0400
@@ -1,5 +1,6 @@
 2009-03-21  Ben Abbott <bpabbott@mac.com>
 
+	* plot/__gnuplot_get_var__.m: Add function to get gnuplot variables.
 	* plot/print.m: Restore the behavior for option -S<num>,<num>.
 
 2009-03-19  Jaroslav Hajek <highegg@gmail.com>
diff -r cc916241e811 -r b3268a0458f2 scripts/plot/Makefile.in
--- a/scripts/plot/Makefile.in	Sat Mar 21 09:35:35 2009 -0400
+++ b/scripts/plot/Makefile.in	Sat Mar 21 12:49:58 2009 -0400
@@ -47,6 +47,7 @@
   __errcomm__.m \
   __errplot__.m \
   __ezplot__.m \
+  __gnuplot_get_var__.m \
   __gnuplot_has_feature__.m \
   __go_close_all__.m \
   __go_draw_axes__.m \
diff -r cc916241e811 -r b3268a0458f2 scripts/plot/__gnuplot_get_var__.m
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/plot/__gnuplot_get_var__.m	Sat Mar 21 12:49:58 2009 -0400
@@ -0,0 +1,151 @@
+## Copyright (C) 2009 Ben Abbott
+##
+## 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/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{value} =} __gnuplot_get_var__ (@var{h}, @var{name}, @var{fmt})
+## Undocumented internal function.
+## @end deftypefn
+
+## Author: Ben Abbott <bpabbott@mac.com>
+## Created: 2009-02-07
+
+function gp_var_value = __gnuplot_get_var__ (h, gp_var_name, fmt)
+
+  if (nargin == 0)
+    h = gcf ();
+  endif
+  if (nargin < 2)
+    print_usage ();
+  endif
+  if (nargin < 3)
+    fmt = '';
+  endif
+
+  if (numel (h) == 1 && isfigure (h))
+    ostream = get (h, "__plot_stream__");
+  else
+    ostream = h;
+  endif
+  if (numel (ostream) < 1)
+    error ("__gnuplot_get_var__: stream to gnuplot not open");
+  elseif (ispc ()) # || true
+    if (numel (ostream) == 1)
+      error ("__gnuplot_get_var__: Need mkfifo that is not implemented under Windows");
+    endif
+    use_mkfifo = false;
+    istream = ostream(2);
+    ostream = ostream(1);
+  else
+    use_mkfifo = true;
+    ostream = ostream(1);
+  endif
+
+  if (use_mkfifo)
+    gpin_name = tmpnam ();
+
+    ## Mode: 6*8*8 ==  0600
+    [err, msg] = mkfifo (gpin_name, 6*8*8);
+
+    if (err != 0)
+      error ("__gnuplot_get_var__: Can not open fifo (%s)", msg);
+    endif
+  endif
+
+  gp_var_name = strtrim (gp_var_name);
+  n = min (strfind (gp_var_name, " "), strfind (gp_var_name, ",")) - 1;
+  if (isempty (n))
+    n = numel (gp_var_name);
+  endif
+
+  unwind_protect
+
+    ## Notes: Variables may be undefined if user closes gnuplot by "q"
+    ## or Alt-F4. Further, this abrupt close also requires the leading
+    ## "\n" on the next line.
+    if (use_mkfifo)
+      fprintf (ostream, "\nset print \"%s\";\n", gpin_name);
+      fflush (ostream);
+      [gpin, err] = fopen (gpin_name, "r");
+      if (err != 0)
+        error ("__gnuplot_get_var__: Can not open fifo (%s)", msg);
+      endif
+      gp_cmd = sprintf ("\nif (exists(\"%s\")) print %s; else print NaN\n",
+                        gp_var_name(1:n), gp_var_name);
+      fputs (ostream, gp_cmd);
+
+      ## Close output file, to force it to be flushed
+      fputs (ostream, "set print;\n");
+      fflush (ostream);
+
+      ## Now read from fifo.
+      reading = true;
+      str = {};
+      while (reading)
+        str{end+1} = fgets (gpin);
+        if (isnumeric (str{end}) && (str{end} == -1))
+          reading = false;
+          str = str(1:(end-1));
+        endif
+      endwhile
+      str = strcat (str{:});
+      fclose (gpin);
+    else
+      ## Direct gnuplot to print to <STDOUT>
+      fprintf (ostream, "set print \"-\";\n");
+      fflush (ostream);
+      gp_cmd = sprintf ("\nif (exists(\"%s\")) print \"OCTAVE: \", %s; else print NaN\n",
+                        gp_var_name(1:n), gp_var_name);
+      fputs (ostream, gp_cmd);
+      fflush (ostream);
+      ## Direct gnuplot to print to <STDERR>
+      fputs (ostream, "set print;\n");
+      fflush (ostream);
+
+      str = {};
+      while (isempty (str))
+        str = char (fread (istream)');
+        if (! isempty (str))
+          str = regexp (str, "OCTAVE:.*", "match")
+          str = str{end}(8:end);
+        endif
+        fclear (istream);
+      endwhile
+    endif
+
+    ## Strip out EOLs and the continuation character "|"
+    str(str=="\n") = "";
+    str(str=="\r") = "";
+    n_continue = strfind (str, " \\ ");
+    if (! isempty (n_continue))
+      str(n_continue+1) = "";
+    endif
+
+    if (isempty (fmt))
+      gp_var_value = strtrim (str);
+    else
+      gp_var_value = sscanf (str, fmt);
+    endif
+
+  unwind_protect_cleanup
+    if (use_mkfifo)
+      unlink (gpin_name);
+    endif
+  end_unwind_protect
+
+endfunction
+