Re: Bit field vs bit manipulation?
- From: "Alexander Nickolov" <agnickolov@xxxxxxxx>
- Date: Tue, 14 Aug 2007 11:13:01 -0700
As far as the efficiency of your compression algortihm, you
should compare it to others before you make conclusions.
For example use WinZip on the source file and compare the
resulting size against what you achieve.
As for how this relates to your original question, I have only
a marginal idea. I suppose you want your table values aligned
on 4 bytes boundaries for runtime speed and thus using a bit
field struct.
--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@xxxxxxxx
MVP VC FAQ: http://vcfaq.mvps.org
=====================================
"David Bender" <DavidBender@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:B5702C69-6294-4D04-9DB1-B788975CDABA@xxxxxxxxxxxxxxxx
"Alexander Nickolov" wrote:
I'm not sure what you are really trying to achieve. Do you actually
output a garbage (for example zero) byte after each 3 bytes and
then read it back in order to ensure proper in-memory alignment?
Well, imagine building a table of 4096 entries using 12bit groups.
Now use that same table to find repeating values. Example;
Input 3 bytes, 54 45 64 and the output is 0544 0564. And the
leading zeros are useless.
The object is using a table and an index to re-write any file.
Where the table can be encrypted and the data is not. So,
if the table is unreadable then so is the data.
My last test was on a 733MB file. The table and index was
made the file about 488MB. I think encryption and compressing
to 66% is very good.
.
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- Re: Bit field vs bit manipulation?
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