diff --git a/src/documentation/xdocs/hdf/docoverview.xml b/src/documentation/xdocs/hdf/docoverview.xml index fe864bc2d..977a9a904 100644 --- a/src/documentation/xdocs/hdf/docoverview.xml +++ b/src/documentation/xdocs/hdf/docoverview.xml @@ -1,5 +1,5 @@ - +
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The purpose of this document is to give a brief high level overview of the HDF document format. This document does not go into in-depth technical @@ -20,19 +20,19 @@

The OLE file format is not discussed in this document. It is assumed that the reader has a working knowledge of the POIFS API.

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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.

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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.

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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 @@ -46,9 +46,9 @@ 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.

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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 @@ -57,8 +57,8 @@ from another style.

Eventually, you have to chain back to the nil style which is an imaginary style with certain implied values.

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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.

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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 @@ -85,10 +85,10 @@ 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.

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