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Compression using Zlib (pb5+,Sep 22, 1998)

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Author: Eric Aling
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Download: Download pb5zlib.zip (74Kb) ( pb5zlib.zip, 74Kb )

Although storage is becoming cheaper and cheaper, bandwidth isn't. If you for instance want to send data from one country to another country, using FTP or a database connection, you want to to this as quick as possible. Luckily, there's a thing called hardware compression, which is done by modems. However, this compression is in most cases not that good. We all know about WinZip and other compression tools. Zlib is also one of them, build by some very good authors who also helped with building WinZip. Anyway, Zlib is free and the source code is available on the internet, also with support. I've created a nonvisual which uses this Zlib compression routines, for 16bit and for 32bit. The 32bit version is very fast and compresses really well. With 16bit we have a problem because we can only compress data smaller than 64Kb. With larger data, we need to break the data into pieces of about 64k, compress then and add the compressed parts together. We also need to store some extra information on how this total compressed piece of data is constructed. This is all done by the Nonvisual. Check it out. For more information about Zlib, use yahoo or excite and search on Zlib.

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