<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<!--*** This is a generated file. Do not edit. ***-->
<link rel="stylesheet" href="../skin/tigris.css" type="text/css">
<link rel="stylesheet" href="../skin/mysite.css" type="text/css">
<link rel="stylesheet" href="../skin/site.css" type="text/css">
<link media="print" rel="stylesheet" href="../skin/print.css" type="text/css">
<title>Apache POI - HWPF - Java API to Handle Microsoft Word Files</title>
</head>
<body bgcolor="white" class="composite">
<!--================= start Banner ==================-->
<div id="banner">
<table width="100%" cellpadding="8" cellspacing="0" summary="banner" border="0">
<tbody>
<tr>
<!--================= start Group Logo ==================-->
<td width="50%" align="left">
<div class="groupLogo">
<a href="http://poi.apache.org"><img border="0" class="logoImage" alt="Apache POI" src="../resources/images/group-logo.jpg"></a>
</div>
</td>
<!--================= end Group Logo ==================-->
<!--================= start Project Logo ==================--><td width="50%" align="right">
<div align="right" class="projectLogo">
<a href="http://poi.apache.org/"><img border="0" class="logoImage" alt="POI" src="../resources/images/project-logo.jpg"></a>
</div>
</td>
<!--================= end Project Logo ==================-->
</tr>
</tbody>
</table>
</div>
<!--================= end Banner ==================-->
<!--================= start Main ==================-->
<table width="100%" cellpadding="0" cellspacing="0" border="0" summary="nav" id="breadcrumbs">
<tbody>
<!--================= start Status ==================-->
<tr class="status">
<td>
<!--================= start BreadCrumb ==================--><a href="http://www.apache.org/">Apache</a> | <a href="http://poi.apache.org/">POI</a><a href=""></a>
<!--================= end BreadCrumb ==================--></td><td id="tabs">
<!--================= start Tabs ==================-->
<div class="tab">
<span class="selectedTab"><a class="base-selected" href="../index.html">Home</a></span> | <script language="Javascript" type="text/javascript">
function printit() {
if (window.print) {
window.print() ;
} else {
var WebBrowser = '<OBJECT ID="WebBrowser1" WIDTH="0" HEIGHT="0" CLASSID="CLSID:8856F961-340A-11D0-A96B-00C04FD705A2"></OBJECT>';
document.body.insertAdjacentHTML('beforeEnd', WebBrowser);
WebBrowser1.ExecWB(6, 2);//Use a 1 vs. a 2 for a prompting dialog box WebBrowser1.outerHTML = "";
}
}
</script><script language="Javascript" type="text/javascript">
var NS = (navigator.appName == "Netscape");
var VERSION = parseInt(navigator.appVersion);
if (VERSION > 3) {
document.write(' <a title="PRINT this page OUT" href="javascript:printit()">PRINT</a>');
}
</script> | <a title="PDF file of this page" href="docoverview.pdf">PDF</a>
</div>
<!--================= end Tabs ==================-->
</td>
</tr>
</tbody>
</table>
<!--================= end Status ==================-->
<table id="main" width="100%" cellpadding="8" cellspacing="0" summary="" border="0">
<tbody>
<tr valign="top">
<!--================= start Menu ==================-->
<td id="leftcol">
<div id="navcolumn">
<div class="menuBar">
<div class="menu">
<span class="menuLabel">Apache POI</span>
<div class="menuItem">
<a href="../index.html">Top</a>
</div>
</div>
<div class="menu">
<span class="menuLabel">HWPF</span>
<div class="menuItem">
<a href="index.html">Overview</a>
</div>
<div class="menuItem">
<a href="quick-guide.html">Quick Guide</a>
</div>
<div class="menuItem">
<span class="menuSelected">HWPF Format</span>
</div>
<div class="menuItem">
<a href="projectplan.html">HWPF Project plan</a>
</div>
</div>
</div>
</div>
<form target="_blank" action="http://www.google.com/search" method="get">
<table summary="search" border="0" cellspacing="0" cellpadding="0">
<tr>
<td><img height="1" width="1" alt="" src="../skin/images/spacer.gif" class="spacer"></td><td nowrap="nowrap">
Search Apache POI<br>
<input value="poi.apache.org" name="sitesearch" type="hidden"><input size="10" name="q" id="query" type="text"><img height="1" width="5" alt="" src="../skin/images/spacer.gif" class="spacer"><input name="Search" value="GO" type="submit"></td><td><img height="1" width="1" alt="" src="../skin/images/spacer.gif" class="spacer"></td>
</tr>
<tr>
<td colspan="3"><img height="7" width="1" alt="" src="../skin/images/spacer.gif" class="spacer"></td>
</tr>
<tr>
<td class="bottom-left-thick"></td><td bgcolor="#a5b6c6"><img height="1" width="1" alt="" src="../skin/images/spacer.gif" class="spacer"></td><td class="bottom-right-thick"></td>
</tr>
</table>
</form>
</td>
<!--================= end Menu ==================-->
<!--================= start Content ==================--><td>
<div id="bodycol">
<div class="app">
<div align="center">
<h1>Apache POI - HWPF - Java API to Handle Microsoft Word Files</h1>
</div>
<div class="h3">
<a name="The+Word+97+File+Format+in+semi-plain+English"></a>
<div class="h3">
<h3>The Word 97 File Format in semi-plain English</h3>
</div>
<p>The purpose of this document is to give a brief high level overview of the
HWPF document format. This document does not go into in-depth technical
detail and is only meant as a supplement to the Microsoft Word 97-2007
Binary File Format freely available from
<a href="http://www.microsoft.com/interop/docs/officebinaryformats.mspx">Microsoft</a>.</p>
<p>The OLE file format is not discussed in this document. It is assumed that
the reader has a working knowledge of the POIFS API. </p>
<a name="Word+file+structure"></a>
<div class="h4">
<h4>Word file structure</h4>
</div>
<p>A Word file is made up of the document text and data structures
containing formatting information about the text. Of course, this is a
very simplified illustration. There are fields and macros and other
things that have not been considered. At this stage, HWPF is mainly
concerned with formatted text.</p>
<a name="Reading+Word+files"></a>
<div class="h4">
<h4>Reading Word files</h4>
</div>
<p>The entry point for HWPF's reading of a Word file is the File Information
Block (FIB). This structure is the entry point for the locations and size
of a document's text and data structures. The FIB is located at the
beginning of the main stream.</p>
<a name="Text"></a>
<div class="h2">
<h2>Text</h2>
</div>
<p>The document's text is also located in the main stream. Its starting
location is given as FIB.fcMin and its length is given in bytes by
FIB.ccpText. These two values are not very useful in getting the text
because of unicode. There may be unicode text intermingled with ASCII
text. That brings us to the piece table.</p>
<p>The piece table is used to divide the text into non-unicode and unicode
pieces. The size and offset are given in FIB.fcClx and FIB.lcbClx
respectively. The piece table may contain Property Modifiers (prm).
These are for complex(fast-saved) files and are skipped. Each text piece
contains offsets in the main stream that contain text for that piece.
If the piece uses unicode, the file offset is masked with a certain bit.
Then you have to unmask the bit and divide by 2 to get the real file
offset. </p>
<a name="Text+Formatting"></a>
<div class="h2">
<h2>Text Formatting</h2>
</div>
<a name="Stylesheet"></a>
<div class="h5">
<h5>Stylesheet</h5>
</div>
<p>All text formatting is based on styles contained in the StyleSheet.
The StyleSheet is a data structure containing among other things, style
descriptions. Each style description can contain a paragraph style and
a character style or simply a character style. Each style description
is stored in a compressed version on file. Basically these are deltas
from another style.</p>
<p>Eventually, you have to chain back to the nil style which is an
imaginary style with certain implied values.</p>
<a name="Paragraph+and+Character+styles"></a>
<div class="h5">
<h5>Paragraph and Character styles</h5>
</div>
<p>Paragraph and Character formatting properties for a document's text are
stored on file as deltas from some base style in the Stylesheet. The
deltas are used to create a complete uncompressed style in memory.</p>
<p>Uncompressed paragraph styles are represented by the Pargraph
Properties(PAP) data structure. Uncompressed character styles are
represented by the Character Properties(CHP) data structure. The styles
for the document text are stored in compressed format in the
corresponding Formatted Disk Pages (FKP). A compressed PAP is referred
to as a PAPX and a compressed CHP is a CHPX. The FKP locations are
stored in the bin table. There are seperate bin tables for CHPXs and
PAPXs. The bin tables' locations and sizes are stored in the FIB.</p>
<p>A FKP is a 512 byte OLE page. It contains the offsets of the beginning
and end of each paragraph/character run in the main stream and the
compressed properties for that interval. The compessed PAPX is based on
its base style in the StyleSheet. The compressed CHPX is based on the
enclosing paragraph's base style in the Stylesheet.</p>
<a name="Uncompressing+styles+and+other+data+structures"></a>
<div class="h5">
<h5>Uncompressing styles and other data structures</h5>
</div>
<p>All compressed properties(CHPX, PAPX, SEPX) contain a grpprl. A grpprl
is an array of sprms. A sprm defines a delta from some base property.
There is a table of possible sprms in the Word 97 spec. Each sprm is a
two byte operand followed by a parameter. The parameter size depends on
the sprm. Each sprm describes an operation that should be performed on
the base style. After every sprm in the grpprl is performed on the base
style you will have the style for the paragraph, character run,
section, etc.</p>
<div id="authors" align="right">by S. Ryan Ackley</div>
</div>
</div>
</div>
</td>
<!--================= end Content ==================-->
</tr>
</tbody>
</table>
<!--================= end Main ==================-->
<!--================= start Footer ==================-->
<div id="footer">
<table summary="footer" cellspacing="0" cellpadding="4" width="100%" border="0">
<tbody>
<tr>
<!--================= start Copyright ==================-->
<td colspan="2">
<div align="center">
<div class="copyright">
Copyright © 2002-2011 The Apache Software Foundation. All rights reserved.<br>
Apache POI, POI, Apache, the Apache feather logo, and the Apache
POI project logo are trademarks of The Apache Software Foundation.
</div>
</div>
</td>
<!--================= end Copyright ==================-->
</tr>
<tr>
<td align="left">
<!--================= start Host ==================-->
<!--================= end Host ==================--></td><td align="right">
<!--================= start Credits ==================-->
<div align="right">
<div class="credit"></div>
</div>
<!--================= end Credits ==================-->
</td>
</tr>
</tbody>
</table>
</div>
<!--================= end Footer ==================-->
</body>
</html>
