[fpc-pascal] helpsystem, some numbers

[Eduardo Morras]

At 15:19 27/10/2008, you wrote:

>This morning I did a bit research after the help files, I hope it sheds some
>light on the WHY for the recent CHM efforts:
>
>                      html           html
>help package    size on disk(k)  real size(k) chm(k)
>rtl                38816          22096       1865
>lcl                107404         72499       5227
>fcl                8548            5148        445
>-------------------------------------------------------
>All                154768         99743       7537
>
>The disk is NTFS, so probably 4kb clustersize.
>
>Total html bzip2'ed :  2.9MB or so
>Total html zipped   :  25MB
>total chm  bzip2'ed :  6,7MB
>
>Extraction time html: 1 minute+ (Core 2 6600 (2.4GHz), winXP's unzip)
>Extraction time chm : not measurable.
>
>Note that while the bzip2 archive is very small, it must be unpacked
>entirely before use, contrary to either zip (in theory you could open the
>zip and extract only the one file) and chm (which has several indexes
>internally too, the unpacked chm is possibly larger than the html due to
>this)

Don't know what's your question (perhaps you posted on wrong list) 
but chm uses LZX compression algorithm internally. You can see that 
you can't compress too much a chm (from 7,5 MB to 6,7). Bzip2 is 
block oriented and you can decompress each block separately. You can 
choose between 100K to 900K block sizes that corresponds to 1-9 bzip2 
switch. Bzip2 has the same API than zlib and (if my memory don't 
fails) allows you to extract a single file.

HTH 
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