--- a/main/io/inst/private/__OCT_oct2xlsx__.m	Tue Mar 11 08:08:15 2014 +0000
+++ b/main/io/inst/private/__OCT_oct2xlsx__.m	Mon Mar 17 22:15:35 2014 +0000
@@ -1,4 +1,5 @@
 ## Copyright (C) 2013,2014 Markus Bergholz
+## Parts Copyright (C) 2014 Philip Nienhuis
 ##
 ## This program 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
@@ -20,7 +21,7 @@
 ## usage:
 ##	__OCT_oct2xlsx__(filename, matrix, wsh, range, spsh_opts)
 ##
-##	matrix: have to be a 2D Matrix. NaN will be an empty cell in Excel. Strings are not supported!
+##	matrix: have to be a 2D cell array. NaN will be an empty cell in Excel.
 ##
 ##	wsh: can be a 1, 2 or 3 for indexing the worksheet. >3 is not supported yet!
 ##	wsh: can be string for naming the worksheet. the string has a limit length of 31!
@@ -41,7 +42,8 @@
 ##	Elapsed time is 253.35110616684 seconds.
 ## @end deftypefn
 
-## Author: Markus Bergholz <markuman@gmail.com>
+## Author: Markus Bergholz <markuman at gmail.com>
+## Amended by Philip Nienhuis <prnienhuis at users.sf.net>
 ## ToDo
 ## - use english language as default (atm it's all german. "Tabelle1" instead of "Table1").
 ## - fix write to defined range (rows still starts a row 1)
@@ -67,110 +69,440 @@
 ## Version 0.1
 ## 2013/11/08		- Initial Release
 
-function [xls, rstatus] = __OCT_oct2xlsx__ (filename, matrix, wsh=1, crange="", spsh_opts, obj_dims)
+function [xls, rstatus] = __OCT_oct2xlsx__ (matrix, xls, wsh=1, crange="", spsh_opts, obj_dims)
+
+  ## Analyze worksheet parameter & determine if new sheet is required
+  new_sh = 0;
+  if (ischar (wsh))
+    if (31 < length (wsh))
+      error ("Worksheet name longer than 31 characters is not supported by Excel");
+    endif
+    wsh_number = strmatch (wsh, xls.sheets.sh_names);
+    if (isempty (wsh_number))
+      ## Worksheet not in stack. We'll create a new one
+      new_sh = 1;
+      wsh_number = numel (xls.sheets.sh_names) + 1;
+      if (xls.changed == 3)
+        wsh_number--;
+      endif
+      xls.sheets.sh_names(end+1) = wsh;
+    endif
+    wsh_string = wsh;
 
-% ####### Below code already in caller
-%if (isempty (crange))
-%  offset.row = 0;
-%  offset.col = 0;
-%else
-%  offset.row = str2double (cell2mat (regexp (crange, '(\d*)', 'tokens'))) - 1;
-%  offset.col = __OCT_cc__ (cell2mat (cell2mat (regexp (crange, '([A-Z]*)', 'tokens')))) - 1;
-%endif
+  elseif (isnumeric (wsh))
+    if (wsh > numel (xls.sheets.sh_names))
+      ## New worksheet
+      new_sh = 1;
+      ## Default sheet name
+      wsh_string = sprintf ("Sheet%d", wsh);
+      ## It may already exist...
+      while (! isempty (strmatch (wsh_string, xls.sheets.sh_names)) && length (wsh_string <= 31))
+        wsh_string = strrep (wsh_string, "Sheet", "Sheet_");
+      endwhile
+      if (length (string) > 31)
+        error ("oct2xls: cannot add worksheet with a unique name");
+      endif
+      ## The sheet index number can't leave a gap in the stack, so:
+      wsh_number = numel (xls.sheets.sh_names) + 1;
+      xls.sheets.sh_names(end+1) = wsh_string;
+    else
+      wsh_number = wsh;
+    endif
+  endif
+
+  if (spsh_opts.formulas_as_text == 0)
+    ## Provisionally only read/write strings, not formulas
+    ## FIXME actually a formula evaluator is required to process formulas
+    spsh_opts.formulas_as_text = 1;
+  endif
 
-% ####### Below code already in oct2xls
-%# Input matrix check
-%# ==================
-%if (ndims (matrix) != 2)
-%  error ("xlsxwrite only supports 2D matrix");
-%endif
-%
-%if (1048576 < rows (matrix))
-%  error ("Too many rows. Excel is limited to 1,048,576 rows!");
-%endif
-%if 16384 < columns (matrix)
-%  error ("Too many columns. Excel is limited to 16,384 colums!");
+  if (new_sh)
+    rawarr = {};
+    lims = [];
+  else
+    ## Get all data in sheet and row/column limits
+    [rawarr, xls]  = __OCT_xlsx2oct__ (xls, wsh, "", spsh_opts);
+    lims = xls.limits;
+  endif
+  
+  ## Merge old and new data. Provisionally allow empty new data to wipe old data
+  [rawarr, lims, onr, onc] = __OCT_merge_data__ (rawarr, lims, matrix, obj_dims, spsh_opts);
+
+## FIXME - contains stuff that won't work with existing sheets
+##         (though I like the idea PRN)
+%## something cool, that matlab doesn't support
+%# xlswrite('myfile.xlsx',matrix,{'1','Sheetname'})
+%if (iscell (wsh))
+%  # check size
+%  if (1 ~= rows (wsh) || 2 ~= columns (wsh))
+%    error ("Too many input arguments for wsh");
+%  endif
+%  # check first argument
+%  if (1 == ischar (wsh{1,1}))
+%    if (31 < length (wsh{1,1}))
+%      error ("Worksheet name longer than 31 characters is not supported by Excel");
+%    endif
+%    wsh_string=wsh{1,1};
+%  elseif (isnumeric (wsh{1,1}))
+%    if (1 ~= ismember (wsh{1,1} ,1:3))
+%      error ("wsh index must be 1, 2 or 3");
+%    endif
+%    wsh_number = wsh{1,1};
+%  else
+%    error ("wsh should contain one numeric value (for indexing) and one string (for naming)");
+%  endif
+%  
+%  # check second argument
+%  if (ischar (wsh{1,2}))
+%    if (31 < length(wsh{1,2}))
+%      error ("Worksheet name longer than 31 characters is not supported by Excel");
+%    endif 
+%    wsh_string = wsh{1,2};
+%  elseif (isnumeric (wsh{1,2}))
+%    if (! ismember (wsh{1,2} ,1:3))
+%      error ("wsh index must be 1, 2 or 3");
+%    endif
+%    wsh_number = wsh{1,2};
+%  else
+%    error ("wsh should contain one numeric value (for indexing) and one string (for naming)");
+%  endif
 %endif
 
-############## Nakijken, we hebben niet alles nodig
+## What needs to be done:
+## - Find out worksheet number (easy, wsh_number)
+## - Write data to <temp>/xl/worksheets/sheet<wsh_number>.xml
+##   * For each string, check (persistent var) if sharedStrings.xml exists
+##     > If not, create it.
+##   * For each string check if it is in <temp>/sharedStrings.xml
+##     > if YES, put pointer in new worksheet
+##     > if NO, add node in sharedStrings.xml and pointer in new worksheet
+## - If needed (new file) update <temp>/workbook.xml w. sheet name & sheetId higher than any existing sheetId
+## - Update workbook_rels.xml
+
+  ## Write data to worksheet file
+  [xls, status]  = __OCT_oct2xlsx_sh__ (xls, wsh_number, rawarr, lims, onc, onr, spsh_opts);
+
+  ## Update worksheet bookkeeping
+  if (new_sh)                          ## !!!!! FIXME To be tested !!!!!!
+    ## Read xl/_rels/workbook.xml.rels
+    rid = fopen ([xls.workbook filesep "xl" filesep "_rels" filesep "workbook.xml.rels"], "r+");
+    rxml = fread (rid, Inf, "char=>char").';
+    fclose (rid);
+    ## Add worksheet entry. First find unique rId
+    rId = str2double (cell2mat (regexp (rxml, 'Id="rId(\d+)"', "tokens")));
+    ## Assess rId (needed in [Content_Types].xml, below)
+    nwrId = sort (rId)(end) + 1;
 
-## FIXME
-# when file exist, it gets complicated
-if (ischar (wsh))
-  if (31 < length (wsh))
-    error ("Worksheet name longer than 31 characters is not supported by Excel");
-  endif
-  wsh_string = wsh;
-  wsh_number = 1;
-elseif (isnumeric (wsh))
-  if (1 == wsh)
-    wsh_number = wsh;
-    wsh_string = "Tabelle1";
-  elseif (2 == wsh)
-    wsh_number = wsh;
-    wsh_string = ("Tabelle2");
-  elseif 3 == wsh
-    wsh_number = wsh;
-    wsh_string = "Tabelle3";
-  else 
-    error('wsh index must be 1, 2 or 3');
-  endif
-endif
+    ## <workbook.xml>
+    wid = fopen ([xls.workbook filesep "xl" filesep "workbook.xml"], "r+");
+    wxml = fread (wid, Inf, "char=>char").';
+    fclose (wid);
+    [sheets, is, ie] = getxmlnode (wxml, "sheets");
+    sheetids = str2double (cell2mat (regexp (sheets, ' sheetId="(\d+?)"', "tokens")));
+    if (xls.changed == 3)
+      ## No new sheet, just update Sheet1 name
+      shnum = 1;
+      sheets = strrep (sheets, 'name="Sheet1"', ['name="' wsh_string '"']);
+    else
+      shnum = max(sheetids)+1;
+      wshtag = sprintf ('<sheet name="%s" sheetId="%d" r:id="rId%d" />', ...
+                        wsh_string, shnum, nwrId);
+      sheets = strrep (sheets, "/></sheets>", ["/>" wshtag "</sheets>"]);
+    endif
+    ## Re(/over-)write workbook.xml; start at sheets node
+    wid = fopen ([xls.workbook filesep "xl" filesep "workbook.xml"], "w+");
+    fprintf (wid, "%s", wxml(1:is-1));
+    fprintf (wid, "%s", sheets);
+    fprintf (wid, "%s", wxml(ie+1:end));
+    fclose (wid);
 
-## something cool, that matlab doesn't support
-# xlswrite('myfile.xlsx',matrix,{'1','Sheetname'})
-if (iscell (wsh))
-  # check size
-  if (1 ~= rows (wsh) || 2 ~= columns (wsh))
-    error ("Too many input arguments for wsh");
-  endif
-  # check first argument
-  if (1 == ischar (wsh{1,1}))
-    if (31 < length (wsh{1,1}))
-      error ("Worksheet name longer than 31 characters is not supported by Excel");
+    ## Write xl/_rels/workbook.xml.rels. Only needed for existing files/new sheets
+    if (xls.changed != 3)
+      ## workbook.xml.rels
+      entry = sprintf ('<Relationship Id="rId%d" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" Target="worksheets/sheet%d.xml"/>', nwrId, shnum);
+      rxml = strrep (rxml, "/></Relationships>", ["/>" entry "</Relationships>"]);
+      rid = fopen ([xls.workbook filesep "xl" filesep "_rels" filesep "workbook.xml.rels"], "w");
+      fprintf (rid, "%s", rxml);
+      fclose (rid);
+      ## [Content_Types].xml. Insert worksheet #n entry
+      tid = fopen ([xls.workbook filesep "[Content_Types].xml"], "r+");
+      txml = fread (tid, Inf, "char=>char").';
+      fclose (tid);
+      partname = ['<Override PartName="/xl/worksheets/sheet%d.xml" ' ...
+                  'ContentType="application/vnd.openxmlformats-' ...
+                  'officedocument.spreadsheetml.worksheet+xml"/>' ];
+      partname = sprintf (partname, nwrId);
+      srchstr = 'worksheet+xml"/>';
+      ipos = strfind (txml, srchstr)(end) + length (srchstr);
+      tid = fopen ([xls.workbook filesep "[Content_Types].xml"], "w");
+      fprintf (tid, "%s", txml(1:ipos-1));
+      fprintf (tid, partname);
+      fprintf (tid, txml(ipos:end));
+      fclose (tid);
     endif
-    wsh_string=wsh{1,1};
-  elseif (isnumeric (wsh{1,1}))
-    if (1 ~= ismember (wsh{1,1} ,1:3))
-      error ("wsh index must be 1, 2 or 3");
-    endif
-    wsh_number = wsh{1,1};
-  else
-    error ("wsh should contain one numeric value (for indexing) and one string (for naming)");
-  endif
-  
-  # check second argument
-  if (ischar (wsh{1,2}))
-    if (31 < length(wsh{1,2}))
-      error ("Worksheet name longer than 31 characters is not supported by Excel");
-    endif 
-    wsh_string = wsh{1,2};
-  elseif (isnumeric (wsh{1,2}))
-    if (! ismember (wsh{1,2} ,1:3))
-      error ("wsh index must be 1, 2 or 3");
+
+    ## <docProps/app.xml>
+    aid = fopen ([xls.workbook filesep "docProps" filesep "app.xml"], "r+");
+    axml = fread (wid, Inf, "char=>char").';
+    fclose (aid);
+    wshnode = sprintf ('<vt:lpstr>%s</vt:lpstr>', wsh_string);
+    if (xls.changed == 3)
+      [vt, is, ie] = getxmlnode (axml, "TitlesOfParts");
+      ## Just replace Sheet1 entry by new name
+      vt = strrep (vt, '>Sheet1<', ['>' wsh_string '<']);
+    else
+      ## 1. Update HeadingPairs node
+      [vt1, is, ie] = getxmlnode (axml, "HeadingPairs");
+      ## Bump number of entries
+      nshts = str2double (getxmlnode (vt1, "vt:i4", [], 1)) + 1;
+      vt1 = regexprep (vt1, '<vt:i4>(\d+)</vt:i4>', ["<vt:i4>" sprintf("%d", nshts) "</vt:i4>"]);
+      ## 2. Update TitlesOfParts node
+      [vt2, ~, ie] = getxmlnode (axml, "TitlesOfParts", ie);
+      ## Bump number of entries
+      nshts = str2double (getxmlattv (vt2, "size")) + 1;
+      vt2 = regexprep (vt2, 'size="(\d+)"', ['size="' sprintf("%d", nshts) '"']);
+      ## Add new worksheet entry
+      vt2 = strrep (vt2, "</vt:lpstr></vt:vector>", ["</vt:lpstr>" wshnode "</vt:vector>"]);
+      vt = [vt1 vt2];
     endif
-    wsh_number = wsh{1,2};
-  else
-    error ("wsh should contain one numeric value (for indexing) and one string (for naming)");
+    ## Re(/over-)write workbook.xml; start at sheets node
+    aid = fopen ([xls.workbook filesep "docProps" filesep "app.xml"], "w+");
+    fprintf (wid, "%s", axml(1:is-1));
+    fprintf (wid, "%s", vt);
+    fprintf (wid, "%s", axml(ie+1:end));
+    fclose (wid);
   endif
-endif
 
-############ Kan vervangen door één functie-call met [be|over]schrijven worksheet
-
-%if (! exist (filename, "file"))
+  ## If needed update sharedStrings entries xml descriptor files
+  if (status > 1)
+    ##  workbook_rels.xml
+    rid = fopen ([xls.workbook filesep "xl" filesep "_rels" filesep "workbook.xml.rels"], "r+");
+    rxml = fread (rid, Inf, "char=>char").';
+    fclose (rid);
+    if (isempty (strmatch ("sharedStrings", rxml)))
+      ## Add sharedStrings.xml entry. First find unique rId
+      rId = str2double (cell2mat (regexp (rxml, 'Id="rId(\d+)"', "tokens")));
+      nwrId = sort (rId)(end) + 1;
+      entry = sprintf ('<Relationship Id="rId%d" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/sharedStrings" Target="sharedStrings.xml"/>', nwrId);
+      rxml = strrep (rxml, "/></Relationships>", ["/>" entry "</Relationships>"]);
+      rid = fopen ([xls.workbook filesep "xl" filesep "_rels" filesep "workbook.xml.rels"], "w");
+      fprintf (rid, "%s", rxml);
+      fclose (rid);
+    endif
 
-  __OCT_OOXML_create_file__ (filename, matrix, wsh_number, wsh_string, offset);
+    ## [Content_Types].xml
+    tid = fopen ([xls.workbook filesep "[Content_Types].xml"], "r+");
+    txml = fread (tid, Inf, "char=>char").';
+    fclose (tid);
+    if (isempty (strmatch ("sharedStrings", txml)))
+      ## Add sharedStrings.xml entry after styles.xml node. First find that one
+      [~, ~, ipos] = regexp (txml, '(?:styles\+xml)(?:.+)(><Over)', 'once');
+      ipos = ipos(1);
+      txml = [txml(1:ipos) '<Override PartName="/xl/sharedStrings.xml" '  ...
+                           'ContentType="application/vnd.openxmlformats-' ...
+                           'officedocument.spreadsheetml.sharedStrings+xml" />' ...
+                           txml(ipos+1:end)];
+      tid = fopen ([xls.workbook filesep "[Content_Types].xml"], "w");
+      fprintf (tid, "%s", txml);
+      fclose (tid);
+    endif
+    
+  endif
 
-%elseif (2 == exist (filename,"file"));
-%
-%  error('sorry, edit an existing file is not implemented yet')
-%  %__OOXML_modify_file(filename, matrix, wsh_number, wsh_string);
-%
-%else
-%
-%  error ("%s is not a file!", filename)
-%
-%endif
+  ## - /docProps/core.xml (user/modifier info & date/time)
+  cid = fopen ([xls.workbook filesep "docProps" filesep "core.xml"], "r+");
+  cxml = fread (cid, Inf, "char=>char").';
+  fclose (cid);
+  cxml = regexprep (cxml, 'dBy>(\w+)</cp:lastM', 'dBy>GNU Octave</cp:lastM');
+  modtime = datevec (now);
+  modtime = sprintf ("%4d-%2d-%2dT%2d:%2d:%2dZ", modtime(1), modtime(2), modtime(3), ...
+                                                 modtime(4), modtime(5), modtime(6));
+  modtime = strrep (modtime, " ", "0");
+  [modf, ia, ib] = getxmlnode (cxml, "dcterms:created", [], 1);
+  cxml(ia:ib) = strrep (cxml(ia:ib), modf, modtime);
+  [modf, ia, ib] = getxmlnode (cxml, "dcterms:modified", [], 1);
+  cxml(ia:ib) = strrep (cxml(ia:ib), modf, modtime);
+  cid = fopen ([xls.workbook filesep "docProps" filesep "core.xml"], "w+");
+  fprintf (cid, "%s", cxml);
+  fclose (cid);
+
+  ## Update status
+  xls.changed = max (xls.changed-1, 1);
+  rstatus = 1;
+
+endfunction
+
 
 
+function [ xls, rstatus ] = __OCT_oct2xlsx_sh__ (xls, wsh_number, matrix, lims, onc, onr, spsh_opts)
+
+  ## Open sheet file (new or old), will be overwritten
+  fid = fopen ([xls.workbook filesep "xl" filesep "worksheets" filesep ...
+                sprintf("sheet%d.xml", wsh_number)], "r+");
+  if (fid < 0)
+    ## Apparently a new sheet. Fill in default xml contents
+    xml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>';
+    xml = [ xml "\n" ];
+    xml = [ xml '<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" ' ];
+    xml = [ xml 'xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" '];
+    xml = [ xml 'xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" '];
+    xml = [ xml 'mc:Ignorable="x14ac" xmlns:x14ac="http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac">'];
+    xml = [ xml '<dimension ref="A1"/><sheetViews><sheetView workbookViewId="0"/></sheetViews>'];
+    xml = [ xml '<sheetFormatPr baseColWidth="10" defaultRowHeight="15" x14ac:dyDescent="0.25"/>'];
+    xml = [ xml '<sheetData/>'];
+    xml = [ xml '<pageMargins left="0.7" right="0.7" top="0.8" bottom="0.8" header="0.3" footer="0.3"/>'];
+    xml = [ xml '</worksheet>' ];
+  else
+    ## Read complete contents
+    xml = fread (fid, Inf, "char=>char").';
+    fclose (fid);
+  endif
+
+  ## Update "dimension" (=range) node
+  [dimnode, is1, ie1] = getxmlnode (xml, "dimension");
+  ## Compute new limits
+  rng = sprintf ("%s:%s", calccelladdress (lims(2, 1), lims(1, 1)), ...
+                          calccelladdress (lims(2, 2), lims(1, 2)));
+
+  ## Open sheet file (new or old) in reset mode, write first part of worksheet
+  fid = fopen ([xls.workbook filesep "xl" filesep "worksheets" filesep ...
+                sprintf("sheet%d.xml", wsh_number)], "w+");
+  fprintf (fid, "%s", xml(1:is1-1));
+  ## Write updated dimension node
+  fprintf (fid, '<dimension ref="%s" />', rng);
+
+  ## Get Sheetdata node
+  [shtdata, is2, ie2] = getxmlnode (xml, "sheetData");
+  ## Write second block of xml until start of sheetData
+  fprintf (fid, "%s", [xml(ie1+1:is2-1) "<sheetData>"]);
+
+  ## Explore data types in matrix
+  typearr = spsh_prstype (matrix, onr, onc, [1:5], spsh_opts);
+
+  if (all (typearr(:) == 1))        ## Numeric
+#   write matrix to sheet%%WSH%%.xml
+#  __OOXML_turbowrite__(sprintf("%s/xl/worksheets/sheet%d.xml",tmpdir,wsh_number), matrix);
+    for r=1:rows(matrix)
+      fprintf (fid, '<row r="%d" spans="%d:%d" x14ac:dyDescent="0.25">', r , ...
+              1+offset. row, columns(matrix)+offset.row);
+      for c = 1:columns(matrix)
+        if 0 == isnan (matrix(r,c))
+          fprintf(fid, sprintf('<c r="%s%d"><v>%f</v></c>', __OCT_cc__(c+offset.col), r, matrix(r,c)));
+        endif
+      endfor
+      fprintf(f, '</row>');
+    endfor
+
+  else
+    ## Heterogeneous array. Write cell nodes depending on content
+    strings = {};
+    str_cnt = uniq_str_cnt = 0;
+    ## Check if there are any strings
+    if (any (typearr(:) == 3))
+      ## Yep. Read sharedStrings.xml
+      try
+        sid = fopen (sprintf ("%s/xl/sharedStrings.xml", xls.workbook), "r+");
+        if (sid > 0)
+          ## File exists => there are already some strings in the sheet
+          shstr = fread (sid, "char=>char").';
+          fclose (sid);
+          ## Extract string values. May be much more than present in current sheet
+          strings = cell2mat (regexp (shstr, '<si><t(?:>(.+?)</t>|(.*)/>)</si>', "tokens"));
+          uniq_str_cnt = str2double (getxmlattv (shstr, "uniqueCount"));
+          ## Make shstr a mueric value
+          shstr = 1;
+        else
+          ## File didn't exist yet
+          shstr = 0;
+        endif
+      catch
+        ## No sharedStrings.xml; implies no "fixed" strings (computed strings can still be there)
+        strings = {};
+        str_cnt = uniq_str_cnt = 0;
+      end_try_catch
+    endif
+    ## Process data row by row
+    for ii=1:rows (matrix)
+      ## Row node opening tag
+      fprintf (fid, '<row r="%d" spans="%d:%d">', ii+lims(2, 1)-1, lims(1, 1), lims(1, 2));
+      for jj=1:columns (matrix)
+        ## Init required attributes. Note leading space
+        addr = sprintf (' r="%s"', calccelladdress (ii+lims(2, 1)-1, jj+lims(1, 1)-1));
+        ## Init optional atttributes
+        stag = ttag = form = "";     ## t: e = error, b = boolean, s/str = string
+        switch typearr(ii, jj)
+          case 1                    ## Numeric
+            ## t tag ("type") is omitted for numeric data
+            val = ["<v>" strtrim(sprintf ("%25.10f", matrix{ii, jj})) "</v>"];
+          case 2                    ## Boolean
+            ttag = ' t="b"';
+            if (matrix{ii, jj})
+              val = ["<v>1</v>"];
+            else
+              val = ["<v>0</v>"];
+            endif
+          case 3                    ## String
+            ttag = ' t="s"';
+            ## FIXME s value provisionally set to 0
+%%          stag = ' s="0"';
+            sptr = strmatch (matrix{ii, jj}, strings, "exact");
+            if (isempty (sptr))
+              ## Add new string
+              strings = [strings matrix{ii, jj}];
+              ++uniq_str_cnt;
+              ## New pointer into sharedStrings (0-based)
+              sptr = uniq_str_cnt;
+            endif
+            ## Val must be pointer (0-based) into sharedStrings.xml
+            val = sprintf ("<v>%d</v>", sptr - 1);
+            ++str_cnt;
+          case 4                    ## Formula
+            form = sprintf ("<f>%s</f>", matrix{ii, jj}(2:end));
+            #val = "<v>?</v>";
+            val = " ";
+          otherwise                 ## (includes "case 5"
+            ## Empty value. Clear address
+            addr = '';
+        endswitch
+        ## Append node to file, include tags
+        if (! isempty (addr))
+          fprintf (fid, '<c%s%s%s>', addr, stag, ttag);
+          if (! isempty (val))
+            fprintf (fid, "%s%s", form, val);
+          endif
+          fprintf (fid, "</c>");
+        endif
+      endfor
+      fprintf(fid, '</row>');
+    endfor
+  endif
+
+  ## Closing tag
+  fprintf (fid, "</sheetData>");
+  ## Append rest of original xml to file and close it
+  fprintf (fid, "%s", xml(ie2+1:end));
+  fclose (fid);
+
+  ## Rewrite sharedStrings.xml, if required
+  if (any (typearr(:) == 3))
+    ## (Re-)write xl/sharedStrings.xml
+    sid = fopen (sprintf ("%s/xl/sharedStrings.xml", xls.workbook), "w+");
+    fprintf (sid, '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>\n');
+    fprintf (sid, '<sst xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" count="%d" uniqueCount="%d">', ...
+             str_cnt, uniq_str_cnt);
+    for ii=1:uniq_str_cnt
+      fprintf (sid, "<si><t>%s</t></si>", strings{ii});
+    endfor
+    fprintf (sid, "</sst>");
+    fclose (sid);
+    ## Check if new sharedStrings file entires are required
+    if (isnumeric (shstr) && (! shstr))
+      rstatus = 2;
+      return;
+    endif
+  endif
+
+  ## Return
+  rstatus = 1;
+
 endfunction

--- a/main/io/inst/private/__OCT_spsh_open__.m	Tue Mar 11 08:08:15 2014 +0000
+++ b/main/io/inst/private/__OCT_spsh_open__.m	Mon Mar 17 22:15:35 2014 +0000
@@ -1,4 +1,4 @@
-## Copyright (C) 2013 Philip Nienhuis
+## Copyright (C) 2013,2014 Philip Nienhuis
 ## Copyright (C) 2013 Markus Bergholz (.xlsx & archive unzip stuff)
 ## 
 ## This program is free software; you can redistribute it and/or modify
@@ -40,7 +40,10 @@
 ##     ''     Shuffled code around to file type order
 ## 2014-01-22 Open new files from template directory in io script directory
 ## 2014-01-23 Move confirm_recursive_rmdir to __OCT_spsh_close__.m
-## 2014-01-29 Support for xlsx and gnumeric
+## 2014-01-29 Support for xlsx and gnumeric
+## 2014-02-08 Fix wrong function name in error msg (couldn't be unzipped)
+## 2014-03-17 Simplify sheet names discovery
+##     ''     Ignore SheetId (nowhere used)
 
 function [ xls, xlssupport, lastintf] = __OCT_spsh_open__ (xls, xwrite, filename, xlssupport, ftype)
 
@@ -89,7 +92,7 @@
     fid = fopen (sprintf ('%s/xl/workbook.xml', tmpdir));
     if (fid < 0)
       ## File open error
-      warning ("xls2oct: file %s couldn't be unzipped", filename);
+      warning ("xls2open: file %s couldn't be unzipped", filename);
       xls = [];
       return
     else
@@ -106,8 +109,9 @@
       fclose (fid);
 
       ## Get sheet names and indices
-      xls.sheets.sh_names = cell2mat (regexp (xml, '<sheet name="(.*?)"(?: r:id="\w+")? sheetId="\d+"', "tokens"));
-      xls.sheets.rid = str2double (cell2mat (regexp (xml, '<sheet name=".*?" sheetId="(\d+)"', "tokens")));
+      sheets = getxmlnode (xml, "sheets", [], 1);
+      xls.sheets.sh_names = cell2mat (regexp (sheets, '<sheet name="(.*?)"', "tokens"));
+##    xls.sheets.rid = str2double (cell2mat (regexp (sheets, ' r:id="rId(\d+)"', "tokens")));
 
     endif