Compress Stream to Stream

[anderbelluno]

Hello, I would like to know if there is any example to compress stream to stream.
Ex:
I have a DataSet that I transform into a Stream, and I would like to compress the stream to another stream.
Today I use zlib to do the compression, but I'm looking for alternatives.
Thanks.

[romankassebaum]

AbDfEnc.Deflate(ASource, ADest, nil);
AbDfDec.Inflate(ASource, ADest, nil);

[romankassebaum]

These are functions that you can simply call without dropping a component on a form.

[anderbelluno]

Sorry, maybe I didn't understand the idea correctly, but after deflate the Stream got bigger, as seen in the image.

[romankassebaum]

The code looks correct. Maybe the image cannot be zipped. You could try a text file instead.

[anderbelluno]

@romankassebaum
I tested it with a text file and with a MemoryDataSet, both worked.
But what's the point of not compressing the image?

[romankassebaum]

It depends on the image you are trying to zip, E,g, a .gif is already compressed so that zipping cannot reduce the size any more. In technical words, zipping tries to reduce the redundancy of a stream. If there is no redundancy you cannot remove it.

[anderbelluno]

Thank you so much for replying, it worked perfectly.
I just have one last question, can I use decompression classes in Delphi 7?

[romankassebaum]

I have no idea, try it.