/usr/share/doc/octave-io/READ-ODS.html

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    <p align="center"><u><font face="Arial, sans-serif"><font size="4">
	<b>ODS support for Octave</b></font></font></u>
</p>
<p align="center"><font face="Arial, sans-serif"><font size="2">
	Copyright � 2009 - 2016 Philip Nienhuis &lt;prnienhuis at users.sf.net&gt;</font></font>
</p>
	<p align="center"><font face="Arial, sans-serif"><font size="2">
	This version October 23, 2016</font></font>
</p>
    <p><font face="Arial, sans-serif"><font size="2">
	<i>(ODS = Open Document Format spreadsheet data format, used by e.g., OpenOffice.org.)</i></font></font>
</p>
<dl><dt>
<p align="left"><font face="Arial, sans-serif"><font size="2">
	<u><b>Files content</b></u></font></font>
</p></dt>
<dt><p align="left"><font face="Arial, sans-serif"><font size="2">
	<i><b>odsread.m</b></i>
	<br>No-hassle read script for reading from an ODS file and parsing the numeric
	and text data into separate arrays.<br></font></font>
</p></dt>
<dt><p><font face="Arial, sans-serif"><font size="2">
	<i><b>odswrite.m</b></i>
	<br>No-hassle write script for writing to an ODS file.</font></font>
</p></dt>
	<dt><font face="Arial, sans-serif"><font size="2"><i><b>odsopen.m</b></i></font></font>&nbsp;</dt>
	<dt><font face="Arial, sans-serif"><font size="2">Get a file pointer to an ODS spreadsheet file.</font></font></dt>
<dt><p><font face="Arial, sans-serif"><font size="2"><i><b>ods2oct.m</b></i>
	<br>Read raw data from an ODS spreadsheet file using the file pointer handed by odsopen.</font></font></p></dt><dt>
	<p><font face="Arial, sans-serif"><font size="2"><i><b>oct2ods.m</b></i>
	<br>Write data to an ODS spreadsheet file using the file pointer handed by odsopen.</font></font></p></dt><dt>
	<p><font face="Arial, sans-serif"><font size="2"><i><b>odsclose.m</b></i>
	<br>Close file handle made by odsopen and -if data have been transfered to a spreadsheet- save
    	data.</font></font></p></dt><dt>
	<p><font face="Arial, sans-serif"><font size="2"><i><b>odsfinfo.m</b></i>
	<br>Explore sheet names and optionally estimated data size of ods files with unknown content.</font></font></p></dt><dt>
	<p><font face="Arial, sans-serif"><font size="2"><i><b>calccelladdress.m</b></i>
	<br>Utility function, can be used to compute a spreadsheet-type cell adress from 1-based row and column numbers.</font></font></p></dt><dt>
	<p><font face="Arial, sans-serif"><font size="2"><i><b>parsecell.m</b></i>
	<br>(contained in Excel xlsread scripts, but works also for ods support) parse raw data (cell array) into separate numeric array and text (cell) array.)</font></font></p></dt><dt>
	<p><font face="Arial, sans-serif"><font size="2"><i><b>chk_spreadsheet_support.m</b></i>
	<br>Internal function for (1) checking, (2) setting up, (3) debugging spreadsheet support. While
	not specifically meant for direct invocation from the Octave prompt (it
	is more useful during initialization of Octave itself) it can be very
	helpful when hunting down issues with spreadsheet support in Octave.</font></font></p></dt>
  <dt>
	<p><font face="Arial, sans-serif"><font size="2"><i><b>test_spsh.m</b></i>, <i><b>io_ods_testscript.m</b></i>
	<br>Undocumented scripts for testing basic operation of ODS spreadsheet functions. Meant for testers and developers, but I don't mind if mere mortal users give it a try as well ;-)</font></font></p><br></dt>  
  

</dl>
    <p align="center"><font face="Arial, sans-serif"><font size="4"><u><b>REQUIRED
    SUPPORT SOFTWARE</b></u></font></font></p><dl>
<DT><FONT FACE="Arial, sans-serif" SIZE=2><U><B>For the native Octave interface (OCT)</B></U></DT><br>
<P>(<u><b>read/write</b></u> support for <b>ODS 1.2</b> (LibreOffice/OpenOffice.org Calc), <b>OOXML</b> (Excel 2007+), and <b>Gnumeric</b>)<br>
<b>NO</b> external support software is required!
</FONT></P>
    	</dl>
<p align="left">
<font face="Arial, sans-serif"><font size="2"><B>Octave >= 3.8.0</B> will do just fine but maybe a bit slow. If you want faster I/O, Java support need to be compiled in, a Java JRE > 1.6.0 must be installed, and one or more of the following is required:</font></font></p>
		<p align="left"><font face="Arial, sans-serif"><font size="2">
		<li><b>odfdom.jar</b> (for the <b>OTK</b> interface, currently the preferred option)<br>
    <ul>(<u>only</u> versions <b>0.7.5</b>,
    	<b>0.8.6</b>, <b>0.8.7</b> and <b>0.8.8</b> (the latter from incubator v. 0.5, see download URL below) work OK!) &amp; <b>xercesImpl.jar</b> (watch out here too! only version 2.9.1 (2007-sep-14) works OK with odfdom). Get them here:
	</font></font></p>

  <li>
  <p align="left"><a href="http://odftoolkit.org/projects/odfdom/pages/Home"><font face="Arial, sans-serif"><font size="2">http://odftoolkit.org/projects/odfdom/pages/Home</font></font></a></p>
  </li><li><p align="left" lang="zxx"><font color="#000080"><font face="Arial, sans-serif"><font size="2"><a href="http://incubator.apache.org/odftoolkit/downloads.html"><font face="Arial, sans-serif"><font size="2">http://incubator.apache.org/odftoolkit/downloads.html</font></font></a> (preferred)</font></font></font></p>
  </li><li><p align="left"><a href="http://www.google.com/search?ie=UTF-8&oe=utf-8&q=xerces-2.9.1+download"><font face="Arial, sans-serif"><font size="2">Google for xerces-2.9.1 download</a></p>
  </li></ul>
  </li>
  <dl><dt><p>
	<br><font face="Arial, sans-serif"><font size="2">and/or</font></font>
</p></dt></dl>
<li><p align="left"><font face="Arial, sans-serif"><font size="2"><b>jopendocument</b></font></font><font face="Arial, sans-serif"><font size="2">&lt;version&gt;</font></font><font face="Arial, sans-serif"><font size="2"><b>.jar</b> (for the <b>JOD</b> interface)</font></font><font face="Arial, sans-serif"><font size="2"><br>
<ul>Get it from <a href="http://www.jopendocument.org/">http://www.jopendocument.org</a></font></font></p><p align="left">
    	<font face="Arial, sans-serif"><font size="2">(jOpenDocument 1.3 (final) is the most recent stable one and recommended for Octave)</font></font></ul>
	</p>
	</li>
<dl><dt><p>
	<br><font face="Arial, sans-serif"><font size="2">and/or</font></font>
</p></dt></dl>
	<li>
	<p align="left"><font face="Arial, sans-serif"><font size="2"><b>OpenOffice.org</b> (or clones like <b>LibreOffice</b>, <b>Go-Office</b>, ...) (for the <b>UNO</b> interface)</font></font></font></font><font face="Arial, sans-serif"><font size="2"><br>
	
<ul>Get it from <a href="http://www.openoffice.org/">http://www.openoffice.org</a>. The relevant Java class libs are <b>unoil.jar</b>, 
	<b>unoloader.jar</b>, <b>jurt.jar</b>, <b>juh.jar</b> and <b>ridl.jar</b> (which are scattered around the OOo installation directory), while also the <b>&lt;OOo&gt;/program/</b> 
	directory needs to be in the classpath.<br>
  <b>NOTE</b>: <i>OOo's / LO's arch type (32-bit or 64-bit) must match Octave's arch. In other words, 64-bit Octave won't work with 32-bit LibreOffice, and vice versa</i>.</font></font></p>
	<p align="left">
	</p>
	</li>
</ul>
	<dl><dt>
	<p><font face="Arial, sans-serif"><font size="2">Whatever Java option, these class libs must be referenced with full pathnames in your javaclasspath.<br>
When the io package gets loaded, a utility function (PKG_ADD) tries to automatically find the Java class libs and adds the ones it found to the javaclasspath; When the io package gets unloaded, these same class libs will be removed from the javaclasspath.<br><br>
  Except for the UNO (OOo) classes, on MinGW the jar files had best be put in /&lt;libdir&gt;/java where &lt;libdir&gt; on MinGW it is usually /lib; on Linux system supplied Java class libs usually reside in /usr/share/java. Alternatively, you can put them in your HOME directory in a subdirectory java (mind case!) - on *nix that would be ~./java, on Windows %USERPROFILE%/java (same level as My Documents). The PKG_ADD routine, that gets run each time the io package is loaded, expects the class libs there; if they are elsewhere, add them in ./share/octave/&lt;version&gt;/m/startup/octaverc using appropriate javaaddpath statements or a chk_spreadsheet_support() call.<br>
  In addition, you can specify a subdirectory using the environment variable OCTAVE_IO_JAVALIBS.<br>
  Once a particular Java class lib has been added to the javaclasspath, it won't be searched anymore nor reloaded from the next search location. The search order is:
  <OL>
  <LI>Specified by the environment variable OCTAVE_IO_JAVALIBS</LI>
  <LI>&lt;HOME_DIR&gt;/java</LI>
  <LI>/usr/share/java (*nix) or /lib/java (MinGW)</LI>
  </OL>
  If you do not want PKG_ADD to load the Java class libs, specify a value of "no", "false" or "0" for the OCTAVE_IO_JAVALIBS environment variable before starting Octave.</font></font>
    	</p></dt><dt><p><br>
    </p></dt></dl>
    <p align="center"><font face="Arial, sans-serif"><font size="4"><u><b>USAGE</b></u></font></font></p>
    	<p><font face="Arial, sans-serif"><font size="2">(see �help
    	ods&lt;function_filename&gt;� in octave terminal.)</font></font></p><p><font face="Arial, sans-serif"><font size="2"><b>odsread</b></font></font>
    	<font face="Arial, sans-serif"><font size="2">is a sort of analog to
    	xlsread and works more or less the same. </font></font><font face="Arial, sans-serif"><font size="2"><b>odsread
    	</b></font></font><font face="Arial, sans-serif"><font size="2">is a
    	mere wrapper for the functions </font></font><font face="Arial, sans-serif"><font size="2"><b>odsopen</b></font></font><font face="Arial, sans-serif"><font size="2">,
    	</font></font><font face="Arial, sans-serif"><font size="2"><b>ods2oct,</b></font></font>
    	<font face="Arial, sans-serif"><font size="2">and </font></font><font face="Arial, sans-serif"><font size="2"><b>odsclose</b></font></font>
    	<font face="Arial, sans-serif"><font size="2">that do file access and
    	the actual reading, plus </font></font><font face="Arial, sans-serif"><font size="2"><b>parsecell</b></font></font>
    	<font face="Arial, sans-serif"><font size="2">for post-processing.</font></font></p><p><font face="Arial, sans-serif"><font size="2"><b>odswrite</b></font></font>
    	<font face="Arial, sans-serif"><font size="2">works similar to
    	xlswrite. It too is a wrapper for scripts which do the actual work
    	and invoke other scripts, a.o. </font></font><font face="Arial, sans-serif"><font size="2"><b>oct2ods</b></font></font><font face="Arial, sans-serif"><font size="2">.</font></font></p><p><font face="Arial, sans-serif"><font size="2"><b>odsfinfo</b></font></font>
    	<font face="Arial, sans-serif"><font size="2">can be used to explore
    	odsfiles with unknown content for sheet names and to get an
    	impression of the data content sizes.</font></font></p><font face="Arial, sans-serif"><font size="2">When you need
    	data from just one sheet, <b>odsread</b> is for you.</font></font><font face="Arial, sans-serif"><font size="2"> But when you need
    	data from multiple sheets in the same spreadsheet file, or if you
    	want to process spreadsheet data by limited-size chunks at a time,
    	<b>odsopen</b> / <b>ods2oct</b> [/<b>parsecell</b>] / � /
    	<b>odsclose</b> sequences provides for much more speed and
    	flexibility as the spreadsheet needs to be read just once rather
    	than repeatedly for each call to <b>odsread</b>.</font></font><dl><dt><p>
    	<font face="Arial, sans-serif"><font size="2">Same reasoning goes for
    	<b>odswrite</b>.</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2">Also, if you use
    	<b>odsopen</b> / �../, you can process multiple spreadsheets
    	simultaneously � just use <b>odsopen</b> repeatedly to get
    	multiple spreadsheet file pointers.</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2">Moreover, after
    	adding data to an existing spreadsheet file, you can fiddle with the
    	filename in the ods file pointer struct to save the data into
    	another, possibly new spreadsheet file.</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2">If you use
    	<b>odsopen</b> / <b>ods2oct</b> / � / <b>oct2ods</b> / �.
    	/  <b>odsclose</b>, <b><u><i>DO NOT FORGET</i></u></b> to invoke <b>odsclose</b> in the
    	end. The file pointers can contain an enormous amount of data and
    	may needlessly keep precious memory allocated. In case of the UNO interface, the hidden OpenOffice.org invocation (soffice.bin) can even block proper closing of
	Octave.</font></font></p></dt><dt><br>
    </dt></dl>
    <p align="center"><font face="Arial, sans-serif"><font size="4"><u><b>SPREADSHEET
    FORMULA SUPPORT, STRIPPING AND ENCODING</b></u></font></font></p><dl>
    	<dt>
    	<font face="Arial, sans-serif"><font size="2">When using the OTK, UNO, and/or OCT
    	interface you can:</font></font></dt></dl>
    <ul>
    	<li>
    	<font face="Arial, sans-serif"><font size="2">(When reading, <b>ods2oct</b>)
    	either read spreadsheet formula results, or the literal formula text
    	strings;</font></font></li><li>
    	<font face="Arial, sans-serif"><font size="2">(When writing, <b>oct2ods</b>)
    	either enter formulas in the worksheet as formulas, or enter them as
    	literal text strings.</font></font></li></ul>
    	<font face="Arial, sans-serif"><font size="2">In short, you can
    	enter spreadsheet formulas and in a later stage read them back,
    	change them and re-enter them in the worksheet.</font></font><font face="Arial, sans-serif"><font size="2"> 
<DT>The behaviour is controlled by an option structure <B>options</B></FONT></FONT> <FONT FACE="Arial, sans-serif" SIZE=2><FONT FACE="Arial, sans-serif" SIZE=2>which has some fields ("flags") that can be set to TRUE or FALSE:</DT>
<ul><li>
    	<font face="Arial, sans-serif"><font size="2"><b>options.formulas_as_text</b></font></font>
    	<font face="Arial, sans-serif"><font size="2">= 0 (the default)
    	implies enter formulas as formulas and read back formula results</font></font><br>
    	<font face="Arial, sans-serif"><font size="2"><b>options.formulas_as_text
    	</b></font></font><font face="Arial, sans-serif"><font size="2">=1 (or
    	any positive integer) means enter formulas as text strings and read
    	them back as text strings.</font></font><dl><dt><font face="Arial, sans-serif"><font size="2">Be aware that
    	there's no formula evaluator in ODS java, not even a formula
    	validator. So if you create formulas in your spreadsheet using
    	</font></font><font face="Arial, sans-serif"><font size="2"><b>oct2ods</b></font></font><font face="Arial, sans-serif"><font size="2">
    	or </font></font><font face="Arial, sans-serif"><font size="2"><b>odswrite</b></font></font><font face="Arial, sans-serif"><font size="2">,
    	do not expect meaningful results when reading those files later on
    	</font></font><font face="Arial, sans-serif"><font size="2"><b>unless</b></font></font>
    	<font face="Arial, sans-serif"><font size="2">you open them in
    	OpenOffice.org Calc and write them back to disk.</font></font></dt><dt>
    	<font face="Arial, sans-serif"><font size="2">You can write all kind
    	of junk as a formula into a spreadsheet cell. There's not much
    	validity checking built into odfdom.jar. I didn't bother to try
    	OpenOffice.org Calc to read such faulty spreadsheets, so I don't
    	know what will happen with spreadsheets containing invalid formulas.
    	But using the above options, you can at least repair them using
    	octave....<br>
	The only exception is if you select the UNO interface, as that invokes
	OpenOffice.org behind the scenes, and OOo obviously has a validator and
	evaluator built-in.</font></font></dt></li>
<LI><DT>options.<B>strip_array</B></FONT></FONT> <FONT FACE="Arial, sans-serif" SIZE=2><FONT FACE="Arial, sans-serif" SIZE=2>= 1 (the default) instructs Octave to strip the output arrays resulting from reading a spreadsheet from empty outer rows and columns.</DT>
<DT>options.<B>strip_array</B></FONT></FONT> <FONT FACE="Arial, sans-serif" SIZE=2><FONT FACE="Arial, sans-serif" SIZE=2>= 0 will return the complete requested output range.</DT></LI>
<LI><DT>options.<B>convert_utf</B></FONT></FONT> <FONT FACE="Arial, sans-serif" SIZE=2><FONT FACE="Arial, sans-serif" SIZE=2>= 0 (the default) leave UTF-8 encoded text strings read from a spreadsheet untouched. Usually this works well as the Octave terminal usually knows how to <I><B>display</B></I> UTF-8 encoded strings - but note that Octve itself has limited support for <I><B>processing</B></I> multibyte-character strings. Windows 10 has proper support for UTF-8 in the cmd.exe terminal (used by Octave); but older Windows versions may need a conversion step:</DT>
<DT>options.<B>convert_utf</B></FONT></FONT> <FONT FACE="Arial, sans-serif" SIZE=2><FONT FACE="Arial, sans-serif" SIZE=2>= 1 currently invokes conversion functions utf82unicode.m (when reading from spreadsheet) or unicode2utf8 (when writing to spreadsheet). This can be useful when the strings in Octave that are intended to be written to spreadsheet file contain characters outside the range [32:127]; e.g., LibreOffice cannot process spreadsheets containing single characters outside that range.</DT></LI>
</UL>
<P><DT><B>Note</B> that when invoking odsread.m and odswrite.m, these options are not available. To use these options you need to invoke ods2oct.m / oct2ods.m as outlined above under <B>USAGE</B></DT></P>
  </ul></dl>
    <p align="center"><font face="Arial, sans-serif"><font size="4"><u><b>GOTCHAS</b></u></font></font></p><dl>
    	<dt><p><font face="Arial, sans-serif"><font size="2">I know of one big
    	gotcha: i.e. reading dates (&amp; time). A less obvious one is Java
    	memory pool allocation size.</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2"><b>Date and time
    	in ODS</b></font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">Octave (as does Matlab)
    	stores dates as a number representing the number of days since
    	January 1, 0 (and as an aside ignores a.o. Pope Gregorius'
    	intervention in 1582 when 10 days were simply skipped).</font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">OpenOffice.org stores
    	dates as text strings like �yyyy-mm-dd�.</font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">MS-Excel stores dates as
    	a number representing the number of days since January 1, 1900 (and
    	as an aside, erroneously assumes 1900 to be a leap year).</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2">Now, converting
    	OpenOffice.org date cell values (actually, character strings flagged
    	by �date� attributes) into Octave looks pretty
    	straightforward. But when the ODS spreadsheet was originally an
    	Excel spreadsheet converted by OpenOffice.org, the date cells can
    	either be OOo date values (i.e.,strings) OR old numerical values
    	from the Excel spreadsheet. </font></font>
    	</p></dt><dt><p><font face="Arial, sans-serif"><font size="2">So: you should
    	carefully check what happens to date cells.</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2">As octave has no
    	�date� or �time� data type, octave date
    	values (usually numerical data) are simply transferred as �floats�
    	to ODS spreadsheets. You'll have to convert the values into dates
    	yourself from within OpenOffice.org.</font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">While adding data and
    	time values has been implemented in the write scripts, the wait is
    	for clever solutions to distinguish dates from floats in octave cell
    	arrays.</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2"><b>Java memory
    	pool allocation size</b></font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">The Java virtual machine
    	(JVM) initializes one big chunk of your computer's RAM in which all
    	Java classes and methods etc. are to be loaded: the Java memory
    	pool. It does this because Java has a very sophisticated �garbage
    	collection� system. At least on Windows, the initial size is
    	2MB and the maximum size is 64MB. On Linux this allocated size is
    	much bigger. This part of memory is where the Java-based ODS octave
    	routines (and the Java-based ods routines) live and keep their
    	variables etc.</font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">For transferring large
    	pieces of information to and from spreadsheets you might hit the
    	limits of this pool. E.g. to be able to handle I/O of an array of
    	around 50,000 cells I needed a memory pool size of 512 MB.</font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">The memory size can be
    	increased by inserting a file called �java.opts�
    	(without quotes) in the directory
    	./share/octave/packages/java-&lt;version&gt; (where the script file
    	javaclasspath.m is located), containing just the following lines:</font></font></p></dt><dt><p>
    	<font face="Courier New, monospace"><font size="2"><b>-Xms16m<br>-Xmx512m</b></font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">(where 16 = initial
    	size, 512 = maximum size (in this example), m stands for Megabyte.
    	This number is system-dependent).</font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">After processing a large
    	chunk of spreadsheet information you might notice that octave's
    	memory footprint does not shrink so it looks like Java's memory pool
    	does not shrink back; but rest assured, the memory footprint is the
    	<i>allocated</i> (reserved) memory size, not the actual used size.
    	After the JVM has done its garbage collection, only the so-called
    	�working set� of the memory allocation is really in use
    	and that is a trimmed-down part of the memory allocation pool. On
    	Windows systems it often suffices to minimize the octave terminal
    	for a few seconds to get a more reasonable memory footprint.</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2"><b>Reading cells
    	containing errors</b></font></font></p></dt><dt><p>
    	<font face="Arial, sans-serif"><font size="2">Spreadsheet cells
    	containing erroneous stuff are transferred to Octave as NaNs. But
    	not all errors can be catched. Cells showing #Value# in
    	OpenOffice.org Calc often contain invalid formulas but may have a 0
    	(null) value stored in the value fields. It is impossible to catch
    	this as there is no run-time formula evaluator (yet) in ODF Toolkit
    	nor jOpenDocument (like there is in Apache POI for Excel).</font></font></p></dt><dt><p><font face="Arial, sans-serif"><font size="2">Smaller gotcha's
    	(only with jOpenDocument 1.2b2, <b>fixed</b> in <b>1.2b3+</b> and
    	<b>1.2 final</b>):</font></font></p></dt></dl>
    <ul>
    	<li><p align="left">
    	<font face="Arial, sans-serif"><font size="2">While reading, empty
    	cells are sometimes not skipped but interpreted with numerical value
    	0 (zero).</font></font></p></li><li><p align="left">
    	<font face="Arial, sans-serif"><font size="2">A valid range MUST be
    	specified, I haven't found a way to discover the actual occupied
    	rows and columns (jOpenDocument can give the physical ones (=
    	capacity) but that doesn't help).</font></font></p></li></ul>
    <dl>
    	<dt><p><font face="Arial, sans-serif"><font size="2">NOT fixed in
    	version 1.2 final nor 1.3b1:</font></font></p></dt></dl>
    <ul>
    	<li><p align="left">
    	<font face="Arial, sans-serif"><font size="2">jOpenDocument doesn't
    	set the so-called &lt;office:value-type='string'&gt;  attribute in
    	cells containing text; as a consequence ODF Toolkit will treat them
    	as empty cells. Ooo will read them OK.</font></font></p></li></ul>
    	<p><br>
    </p>
    <p align="center"><font face="Arial, sans-serif"><font size="4"><u><b>MATLAB
    COMPATIBILITY</b></u></font></font></p>
    	<p><font face="Arial, sans-serif"><font size="2">Depending on the MS-Excel version on the same computer,
    	Matlab may read/write ODS files using xlsread/xlswrite. Note that decent ODS 1.2 support only started with Excel 2013.<br><b>odsread</b> is fairly
    	function-compatible to <b>xlsread</b>, however.</font></font></p><p><font face="Arial, sans-serif"><font size="2">Same goes for <b>odswrite</b>,
    	<b>odsfinfo</b> and <b>xlsfinfo</b> � however <b>ods</b><b>f</b><b>info</b>
    	has better functionality IMO.</font></font></p><br>
	
    <p align="center"><font face="Arial, sans-serif"><font size="4"><u><b>COMPARISON
    OF INTERFACES</b></u></font></font></p>
    	<p><font face="Arial, sans-serif"><font size="2">The <b>ODFtoolkit</b> is
    	the one that gives the best (but slow) results at present. However,
    	parsing xml trees into rectangular arrays is not quite
    	straightforward and the other way round is a real nightmare;
    	odftoolkit up til 0.7.5. did little to hide the gory details for the
    	developers.</font></font></p><dl><dt><p>
    	<font face="Arial, sans-serif"><font size="2">While reading ODS is
    	still OK, writing implies checking whether cells already exist
    	explicitly (in table:table-cells) or implicitly (in
    	number-columns-repeated or number-rows-repeated nodes) or not at all
    	yet in which case you'll need to add various types of parent nodes.
    	Inserting new cells (�nodes�) or deleting nodes implies
    	rebuilding possibly large parts of the tree in memory - nothing for
    	the faint-of-heart. Only with ODFToolkit (odfdom) 0.8.6, 0.8.7 and 0.8.8 things have
    	been simplified for developers.<br>
      Unfortunately, with odftoolkit-0.6.0-incubating and odftoolkit-0.6.1-incubating
      (corresponding to odfdom-0.8.9 and 0.8.10) unresolved dependencies ("jenasin") have been introduced that
      break their functionality for Octave.</font></font></p></dt>
<dt><p><font face="Arial, sans-serif"><font size="2">The <b>jOpenDocument</b>
    	interface is more promising, as it does shield the xml tree
    	details and presents developers something which looks like a
    	spreadsheet model.<br>However, unfortunately
    	the developers decided to shield essential methods by making them
    	'protected' (e.g. the vital getCellType). JopenDocument does support
    	writing. But OTOH many obvious methods are still lacking and formula
    	support is absent (although announced for future version 1.4).<br>And last (but not least)
    	the jOpenDocument developers state that their development is
    	primarily driven by requests from customers who pay for support. I
    	do sympathize with this business model but for Octave needs this may
    	hamper progress for a while.<br>
  In addition, jOpenDocument 1.2 and 1.3b1 still have bugs here and there. For
  one, it doesn't write appropriate OfficeValueType attributes to the cells, so
  there's no way to reliably read and distinguish boolean, string and integer
  values.</font></font></p></dt>
<dt><p><font face="Arial, sans-serif"><font size="2">The (still experimental)
	<b>UNO interface</b>, based on a Java/UNO bridge linking a hidden OpenOffice.org
	invocation to Octave, is the most promising:
	</font></font>
	<ul><li><font face="Arial, sans-serif"><font size="2">
	Admittedly OOo needs some tens of seconds to start for the first time,
	but once OOo is in the operating system's disk cache, it operates much
	faster than ODF or JOD;
	</font></font></li>
	<li><font face="Arial, sans-serif"><font size="2">
	It has built-in formula validator and evaluator;
	</font></font></li>
	<li><font face="Arial, sans-serif"><font size="2">
	It has a much more reliable data parser;
	<li><font face="Arial, sans-serif"><font size="2">
	It can read much more spreadsheet formats than just ODS; .sxc (older OOo and
	StarOffice), but also .xls, .xlsx (Excel), .wk1 (Lotus 123), dbf, etc.
	</font></font></li>
	</font></font></li>
	<li><font face="Arial, sans-serif"><font size="2">
	It consumes only a fraction of the JVM heap memory that the other Java ODS
	spreadsheet solutions need because OOo reads the spreadsheet in its own memory 
	chunk in RAM. The other solutions read, expand, parse and manipulate
	all data in the JVM. In addition, OOo's code is outside the JVM (and
	Octave) while the ODF Toolkit and jOpenDocument classes also reside in the 
	JVM.
	</font></font></li></ul>
  <font face="Arial, sans-serif"><font size="2">However, UNO is not stable yet (see below).
  As stated above, the arch type (32-bit or 64-bit) must match that of Octave.</font>.
</p></dt>
<dt><p><font face="Arial, sans-serif"><font size="2">The <b>OCT (native Octave)</b>
    	interface is also promising as it is completely under control of Octave (-Forge) developers.
      Currently it only offers read and -experimental- write support for ODS (relatively slow), gnumeric (faster) and OOXML (very fast). An immense advantage is that no other external software is required. Write support has not extensively tested yet, however.</font></font></p></dt>

</dl>
	
    <p align="center"><font face="Arial, sans-serif"><font size="4"><u><b>TROUBLESHOOTING</b></u></font></font></p><dl>
    	<dt><p><font face="Arial, sans-serif"><font size="2">Some hints for
    	troubleshooting ODS support are given here.<br>
	Since April 2011 the function chk_spreadsheet_support() has been included in
	the io package. Calling it with arguments ('', 3) (empty string and debug level 3)
	will echo a lot of diagnostics to the screen. Large parts of the steps
	outlined below have been automated in this script.<br>
	Problems with UNO are too complicated to treat them here; most of the troubleshooting has been
	implemented in chk_spreadsheet_support.m, only some general guidelines are
	given below.</font></font>
    	</p></dt></dl>
    <ol>
    	<li><p align="left"><font face="Arial, sans-serif"><font size="2">Check
    	if </font></font><font face="Arial, sans-serif"><font size="2">J</font></font><font face="Arial, sans-serif"><font size="2">ava
    	works.<br>
      <B>NOTE: As of Octave 3.8, Java support is usually built-in in Octave and the below description of the Java package does not apply anymore!</B><br>
      Do a <font face="Courier New, monospace"><font size="2">pkg
    	list</font><font face="Arial, sans-serif"><font size="2"> and
    	see</font></p><p>
    	a. <font face="Arial, sans-serif"><font size="2">If there's a Java
    	package mentioned (then it's installed). If not, install it. <B>Don't do this in Octave 3.8 and higher!!</B></font></p>
    	<p><font face="Arial, sans-serif"><font size="2">b. If there's an
    	asterisk on the java package line (then the package is loaded). If
    	not, do a </font></font><font face="Courier New, monospace"><font size="2">pkg
    	rebuild-auto java</font><font face="Arial, sans-serif"><font size="2"> <B>Don't do this in Octave 3.8 and higher!!</B></font></p>
    </li></ol>
    
    <ol start="2">
    	<li><p align="left"><font face="Arial, sans-serif"><font size="2">Check
    	</font></font><font face="Arial, sans-serif"><font size="2">J</font></font><font face="Arial, sans-serif"><font size="2">ava
    	memory settings. Try </font></font><font face="Courier New, monospace"><font size="2">javamem</font></font></p><p>
    	<font face="Arial, sans-serif"><font size="2">a. If it works, check if
    	it reports sufficiently large max memory (had better be 200 MiB, the
    	bigger the better)</font></font></p>
    	<p align="left"><font face="Arial, sans-serif"><font size="2">b. If it
    	doesn't work, do:</font></font>
    	</p><ol type="a"><p align="left">
    		<font face="Courier New, monospace"><font size="2">rt = java_invoke
    		('java.lang.Runtime', 'getRuntime')</font></font></p><p align="left">
    		<font face="Courier New, monospace"><font size="2">rt.gc</font></font></p><p align="left">
    		<font face="Courier New, monospace"><font size="2">rt.maxMemory
    		().doubleValue () / 1024 / 1024</font></font></p><p align="left">
    		<font face="Arial, sans-serif"><font size="2">The last command will
    		show MaxMemory in MiB.</font></font></p></ol>
    	<p align="left"><font face="Arial, sans-serif"><font size="2">c. In case
    	you have insufficient memory, see in �GOTCHAS�, �Java
    	memory pool allocation size�, how to increase java's memory
    	pre-reservation.</font></font></p></li>
	<li><p align="left"><font face="Arial, sans-serif"><font size="2">Check if all classes
    	(.jarfiles) are in class path. Do a '</font></font><font face="Courier New, monospace"><font size="2">jcp = javaclasspath</font></font><font face="Arial, sans-serif"><font size="2"> (-all)'&nbsp;	(under unix/linux, do '</font></font><font face="Courier New, monospace"><font size="2">jcp
    	= javaclasspath; strsplit (jcp,�:�)</font></font><font face="Arial, sans-serif"><font size="2">'
    	(w/o quotes). See above under �REQUIRED SUPPORT SOFTWARE�
    	what classes should be mentioned.</font></font></p>
	<p align="left"><font face="Arial, sans-serif"><font size="2">If classes (.jar files)
    	ar</font></font><font face="Arial, sans-serif"><font size="2">e</font></font><font face="Arial, sans-serif"><font size="2">
    	missing, download and put them somewhere and add them to the
    	javaclass path with their fully qualified pathname (in quotes) using
    	</font></font><font face="Courier New, monospace"><font size="2">javaaddpath()</font></font><font face="Arial, sans-serif"><font size="2">.</font></font></p></li></ol>
    	<p><font face="Arial, sans-serif"><font size="2">Once all classes
    	are present and in the javaclasspath, the ods interfaces should just
    	work. The only remaining showstoppers are insufficient write
    	privileges for the working directory, a wrecked up octave or some
    	other problems outside octave.</font></font></p>
    <ol start="4">
    	<li><p align="left"><font face="Arial, sans-serif"><font size="2">Try
    	opening an ods file: </font></font>
    	</p><p align="left"><font face="Courier New, monospace"><font size="2">ods1
    	= odsopen ('test.ods', 1, 'otk')</font></font><font face="Arial, sans-serif"><font size="2">.
    	If this works and ods1 is a struct with various fields containing
    	objects, ODF toolkit interface (OTK) works. Do an </font></font><font face="Courier New, monospace"><font size="2">ods1
    	= odsclose (ods1)</font></font> <font face="Arial, sans-serif"><font size="2">to
    	close the file.</font></font></p><p align="left">
    	<font face="Courier New, monospace"><font size="2">ods2 = odsopen
    	('test.ods', 1, 'jod')</font></font><font face="Arial, sans-serif"><font size="2">.
    	If this works and ods2 is a struct with various fields containing
    	objects, jOpenDocument interface (JOD) works as well. Do </font></font><font face="Courier New, monospace"><font size="2">ods2
    	= odsclose (ods2)</font></font> <font face="Arial, sans-serif"><font size="2">to
    	close the file.</font></font></p></li>

	<li><p align="left"><font face="Arial, sans-serif"><font size="2">For the UNO
	interface, at least version 1.2.8 of the Java package is needed plus the following
	Java class libs (jars) and directory:<br>
	* <b>unoil.jar</b> (usually found in subdirectory Basis&lt;version&gt;/program/classes/
	or the like of the OpenOffice.org (&lt;OOo&gt;) installation directory;<br>
	* <b>juh.jar</b>, <b>jurt.jar</b>, <b>unoloader.jar</b> and <b>ridl.jar</b>, usually
	found in the subdirectory URE/share/java/ (or the like) of OOo's installation directory;<br>
	* The subdirectory <b>program/</b> (where soffice[.exe] (or ooffice) resides).<br>
	The exact case (URE or ure, Basis or basis), name ("Basis3.2" or just "basis") and
	subdirectory tree (URE/java or URE/share/java) varies across OOo versions and -clones,
	so chk_spreadsheet_support.m can have a hard time finding all needed classes. In
	particularly bad cases, when chk_spreadsheet_support cannot find them, you might need
	to add one or more of these these classes manually to the javaclasspath.
	</font></font></font></p></li>
</ol>
<p><br>
    </p>
    <p align="center"><font face="Arial, sans-serif"><font size="4"><u><b>DEVELOPMENT</b></u></font></font></p>
    	<p><font face="Arial, sans-serif"><font size="2">As with the Excel
    	r/w stuff, adding new interfaces should be easy and straightforward.
    	Add relevant stanzas for your new interface <b><i>INTF</i></b> in <b>odsopen</b>, <b>odsclose</b>, <b>odsfinfo</b>, <b>oct2ods</b>, <b>ods2oct</b>, <b>getusedrange</b> and add new subfunctions (for the real work) in subdir ./private; you'll need a total of six interface-dependent private functions (see the various examples for each interface in subdir ./private).</font></font></p><p><font face="Arial, sans-serif"><font size="2">Suggestions for
    	future development:</font></font></p>
    	<ul><li><p align="left">
    	<font face="Arial, sans-serif"><font size="2">Speeding up (ODS is 10 X
    	slower than e.g. OOXML !!!). jOpenDocument is much faster but still
    	immature.<br>
	For large spreadsheets, <b>UNO</b> *is* MUCH faster than jOpenDocument but starting up OpenOffice.org
	for the first time can take tens of seconds...<br>
  Note that UNO is still experimental. The issue is that odsclose() will simply
  kill ALL other OpenOffice.org invocations, also those that were not opened
  through Octave! This is related to UNO-Java limitations.<br>
  The underlying issue is that when Octave starts an OpenOffice.org invocation,
  OpenOffice.org must be closed for Octave to be able to exit; otherwise Octave will
  wait for OOo to shut down before it can terminate itself. So Octave must kill
  OOo to be able to terminate.<br>
  A way out hasn't been found yet.
  </font></font></p></li><li><p align="left">
    	�<font face="Arial, sans-serif"><font size="2">Passing function
    	handle� a la Matlab's </font></font><font face="Arial, sans-serif"><font size="2"><b>xlsread</b></font></font></p></li><li><p align="left">
    	<font face="Arial, sans-serif"><font size="2">Adding styles (borders,
    	cell lay-out, font, etc.)</font></font></p></li></ul>
    	<font face="Arial, sans-serif"><font size="2">Some notes on the
    	choice for Java (becoming less relevant as the OCT interface gets more mature):</font></font>
    <ol>
    	<li>
    	<font face="Arial, sans-serif"><font size="2">It saves a LOT of
    	development time to use ready-baked Java classes rather than
    	developing your own routines and thus effectively reinvent the
    	wheel.</font></font></li><li>
    	<font face="Arial, sans-serif"><font size="2">A BIG advantage is that
    	a Java-based solution is platform-independent (�portable�).</font></font></li><li>
    	<font face="Arial, sans-serif"><font size="2">The Java classes offer much more options than just reading and writing. Formatting, recalculation options, hiding/merging cell ranges, etc.</font></font></li><li>
    	<font face="Arial, sans-serif"><font size="2">But Java is known to be
    	not very conservative with resources, especially not when processing
    	XML-based formats.</font></font></li></ol>
    <dl>
    	<dt><font face="Arial, sans-serif"><font size="2">So Java is a
    	compromise between portability and rapid development time versus
    	capacity (and speed).</font></font></dt><dt>
    	<font face="Arial, sans-serif"><font size="2">But IMO data sets larger
    	than 5.10<sup>5</sup> cells should not be kept in spreadsheets
    	anyway. Use real databases for such data sets.</font></font></dt><dt>
    	<br>
    	</dt><dt><font face="Arial, sans-serif"><font size="2"><b>ODFDOM versions</b></font></font></dt><dt>
    	<br>
    	</dt><dt><font face="Arial, sans-serif"><font size="2">I have tried various
    	odfdom versions. As to 0.8 &amp; 0.8.5, while the API has been
    	simplified enormously (finally one can address cells by spreadsheet
    	address rather than find out yourself by parsing the
    	table-column/-row/-cell structure), many irrecoverable bugs have
    	been introduced :-(( </font></font>
    	</dt><dt><font face="Arial, sans-serif"><font size="2">In addition
    	processing ODS files became significantly slower (up to 7 times!).</font></font></dt><dt>
    	<br>
    	</dt><dt><font face="Arial, sans-serif"><font size="2">End of August 2010 
      there's implemented support for odfdom-0.8.6.jar � that version
    	is at last sufficiently reliable to use. The few remaining bugs and
    	limitations could easily be worked around by diving in the older
    	TableTable API. Later on (early 2011) version 0.8.7 has been tested
	too - this needed a few adjustments. Early 2012 odfdom-0.8.8 (from odfdom-0.5-incubator)
  was accepted. In March 2015 odfdom-0.8.10 (odfdom-0.6.1-incubator) was tested but
  alas, it doesn't work (needs extraneous dependencies); clearly the odfdom API (currently at main
	version 0) is not stable yet.</font></font></dt><dt>
    	<font face="Arial, sans-serif"><font size="2">So at the moment
    	(August 2012 = last I looked) only odfdom versions <b>0.7.5</b>,
    	<b>0.8.6</b>, <b>0.8.7</b> and <b>0.8.8</b>(-incubator) are supported.
      <b>0.7.5</b> is <u>deprecated</u>, however.</font></font></dt><dt><br></dt>
  <dt><font face="Arial, sans-serif"><font size="2">If you want to
    	experiment with odfdom 0.8 &amp; 0.8.5, you can try:</font></font></dt></dl>
    <ul>
    	<li>
    	<font face="Arial, sans-serif"><font size="2">odsopen.m (revision
    	7157)</font></font></li><li>
    	<font face="Arial, sans-serif"><font size="2">ods2oct.m (revision
    	7158)</font></font></li><li>
    	<font face="Arial, sans-serif"><font size="2">oct2ods.m (revision
    	7159)</font></font></li></ul>
    	<p><font face="Arial, sans-serif"><font size="2">Enjoy!</font></font></p><p align="center"><font face="Arial, sans-serif"><font size="2">Philip Nienhuis, October 23, 2016</font></font></p><dl><dd><p align="center">
    	<br>
    </p></dd></dl>
    </body></html>
octave-io 2.4.5-1 / usr / share / doc / octave-io / READ-ODS.html
