#Word file formats pdf
#Word file formats code
#Word file formats windows

A perfect Word file format parser would also have to be able to do something intelligent with the embedded spreadsheet. Office has extensive support for compound documents, for example, you can embed a spreadsheet in a Word document. But if youвЂ™re writing everything on your own from scratch, you have to do all that work yourself. If youвЂ™re running on Windows, thereвЂ™s library support for these that makes it trivialвЂ¦ using these features was a shortcut for the Microsoft team.

#Word file formats windows

If you wanted to write a from-scratch binary importer, youвЂ™d have to support things like the Windows Metafile Format (for drawing things) and OLE Compound Storage. This turned out to be not what people wanted.) (It also meant that deleted data in a document was still in the file. On the hard drives of the day, this meant saving a long document took one second instead of thirty. To save a long document quickly, 14 out of 15 times, only the changes are appended to the end of the file, instead of rewriting the whole document from scratch. For example, Excel 95 and 97 have something called вЂњSimple SaveвЂќ which they use sometimes as a faster variation on the OLE compound document format, which just wasnвЂ™t fast enough for mainstream use.

The file format is contorted, where necessary, to make common operations fast.

Lexing and parsing are orders of magnitude slower than blitting. ThereвЂ™s no lexing or parsing involved in loading a file.

These are binary formats, so loading a record is usually a matter of just copying (blitting) a range of bytes from disk to memory, where you end up with a C data structure you can use.

There are a lot of optimizations in the file formats that are intended to make opening and saving files much faster: For the early versions of Excel for Windows, 1 MB of RAM was a reasonable amount of memory, and an 80386 at 20 MHz had to be able to run Excel comfortably. They were designed to be fast on very old computers. The first thing to understand is that the binary file formats were designed with very different design goals than, say, HTML. With a little bit of digging, IвЂ™ll show you how those file formats got so unbelievably complicated, why it doesnвЂ™t reflect bad programming on MicrosoftвЂ™s part, and what you can do to work around it.

and are impossible to read or create correctly.

were created by insanely bad programmers.

are the product of a demented Borg mind.

A normal programmer would conclude that OfficeвЂ™s binary file formats:

#Word file formats code

If you started reading these documents with the hope of spending a weekend writing some spiffy code that imports Word documents into your blog system, or creates Excel-formatted spreadsheets with your personal finance data, the complexity and length of the spec probably cured you of that desire pretty darn quickly. And these вЂњspecsвЂќ look more like C data structures than what we traditionally think of as a spec. These are sufficiently complicated that you have to read another 9 page spec to figure that out. You see, Excel 97-2003 files are OLE compound documents, which are, essentially, file systems inside a single file. But wait, thatвЂ™s not all there is to it! This document includes the following interesting comment:Д®ach Excel workbook is stored in a compound file.

#Word file formats pdf

The Excel 97-2003 file format is a 349 page PDF file. These formats appear to be almost completely insane. Last week, Microsoft published the binary file formats for Office.