What kind of compression would be best?

[Gian Kolbjornsen]

Hi,

I need some advice from those of you that have worked with compression.

I have a file consisting of seven 6 byte strings in a comma seperated text file. The files are approx 6-8 GB each. (all the data in the file is numbers: 6 digit, 6 digit, 6 digit, 6 digit, 3 digit, 3 digit and 3 digit. The 6 digit numbers can be positive and negative. The 3 digit numbers are RGB codes.).

I am going to convert the file so that it consists of 4 longs and 3 bytes. It will be sufficent to store the data. I'll write it to a binary file which should reduce the filesize a bit.

Now for my question:

What would be the best way to compress the file in order to transfer it over the internet? And what kind of ratio should I hope for?

Thank you for taking the time,
Gian

[Michael Mattias]

http://www.powerbasic.com/support/pbforums/showthread.php?t=32614

[jcfuller]

http://www.powerbasic.com/support/pbforums/showthread.php?t=41101

False positive on the virus.

James

[Mike Doty]

http://www.7-zip.org

There are quite a few other sites with 7Zip

If many duplicates a sort and passing unique record numbers could be considered.

[John Gleason]

Gian, I have a compression algorithm for the data you show that does effectively maximum possible compression and is faster than say Winzip "Superfast" selection, but I have a question: do the six-digit numbers always have 6 digits, eg. -654321, or can they be eg. -3454? Or might they be -003456?

[Michael Mattias]

6 digit, 6 digit, 6 digit, 6 digit, 3 digit, 3 digit and 3 digit.....
I am going to convert the file so that it consists of 4 longs and 3 bytes.

Not all three digit numbers will fit in a byte.

> The 3 digit numbers are RGB codes..

Well, these particular 3 digit numbers will, as long as they stay in the range 0x00 thru 0xFF.

When I see "read values from file" and I did not create that file, I always have my doubts. I've just seen too many examples of "that which can never happen" happen.

MCM

[Gösta H. Lovgren-2]

No I always have my doubts. I've just seen too many examples of "that which can never happen" happen.

MCM

Oh, what a weary weary world we live in today.{sound of big breath tiredly and effortly expelled}.

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"What do you take me for, an idiot?"
General Charles de Gaulle (1890-1970),
when a journalist asked him if he was happy
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