--- /dev/null
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.0//EN" "../dtd/document-v10.dtd">
+
+<document>
+ <header>
+ <title>HDF</title>
+ <subtitle>Word file format</subtitle>
+ <authors>
+ <person name="S. Ryan Ackley" email="sackley@cfl.rr.com"/>
+ </authors>
+ </header>
+
+ <body>
+ <s1 title="The Word 97 File Format in semi-plain English">
+
+ <p>The purpose of this document is to give a brief high level overview of the
+ Word 97 document format. This document does not go into in-depth technical
+ detail and is only meant as a supplement to the Microsoft Word 97 Binary
+ File Format written by Microsoft.</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>
+
+ <s2 title="Word file structure">
+ <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, HDF is mainly
+ concerned with formatted text.</p>
+ </s2>
+ <s2 title="Reading Word files">
+ <p>The entry point for HDF'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>
+ <s3 title="Text">
+ <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>
+ </s3>
+ <s3 title="Text Formatting">
+ <s4 title="Stylesheet">
+ <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>
+ </s4>
+ <s4 title="Paragraph and Character styles">
+ <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>
+ </s4>
+ <s4 title="Uncompressing styles and other data structures">
+ <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>
+ </s4>
+ </s3>
+ </s2>
+ </s1>
+ </body>
+</document>
+
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