compress/decompress on OS X

Frank Engel fde101 at fjrhome.net
Tue Nov 9 09:42:43 CST 2004


Why bother with using gzip on the file?  Compress the data before 
putting it into the custom properties (see the 'compress' function).  
This eliminates yet another external dependency  (yes, I know that the 
compression ratio will be slightly less, but the resulting code will be 
more portable, and not rely on having the user install gzip manually, 
or need to deal with tracking it externally...)

Of course, you could also try reading the stack file back as binary 
data and run compress() on that, but it would be somewhat messier.

It would also require more than the size of the file(s) to be 
compressed as temporary space on the drive:

The size of the files, in the form of the original files.
The size of the files, in the custom properties.
More space (less than the size of the files), in the gzipped version of 
the file.

You could help to further reduce this by deleting the temporary stack 
file before writing out the compressed version...


Also, I would recommend a custom property set rather than using the 
properties directly; this should help to avoid name conflicts (if a 
file has the name of an internal Rev property, such as a file named 
"foregroundColor" -- you never know).

So then something like this (plus error checking code, etc.):

on archiveFile intoStack, fileName
   put compress(URL ("binfile:" & fileName)) into the dataFork[fileName] 
of intoStack
   put compress(URL ("resfile:" & fileName)) into the 
resourceFork[fileName] of intoStack
end archiveFile

on extractFile fromStack, nameInArchive, fileNameToCreate
   put decompress(the dataFork[nameInArchive] of fromStack) into URL 
("binfile:" & fileNameToCreate)
   put decompress(the resourceFork[nameInArchive] of fromStack) into URL 
("resfile:" & fileNameToCreate)
end extractFile

On Nov 9, 2004, at 10:25, Cubist at aol.com wrote:

>    Perhaps I'm missing something, but it seems to me that it should be
> possible to create a Rev-only compression utility which can handle any 
> number of
> files, on any platform that Rev supports.
>
>    Step one: Create a new stack.
>    Step two: Do a binfile read of whichever file.
>    Step three: Stick the binary data of that file into a custom 
> property of
> your new stack.
>    Step four: Repeat 2 and 3 as needed, until there are no more files 
> to
> compress.
>    Step five: Use gzip to compress the resulting stack.
>
>    Can anyone think of a reason that this technique *wouldn't* work?
> _______________________________________________
> use-revolution mailing list
> use-revolution at lists.runrev.com
> http://lists.runrev.com/mailman/listinfo/use-revolution
>
>
-----------------------------------------------------------
Frank D. Engel, Jr.  <fde101 at fjrhome.net>

$ ln -s /usr/share/kjvbible /usr/manual
$ true | cat /usr/manual | grep "John 3:16"
John 3:16 For God so loved the world, that he gave his only begotten 
Son, that whosoever believeth in him should not perish, but have 
everlasting life.
$



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