[PLUG] MacBinary( was Re: reading old jpeg format?)

[Leonard Rosenthol <leonardr@lazerware.com>]

At 12:12 PM -0400 8/22/02, gabriel rosenkoetter wrote:
> Ah, this might explain it:
>
> # MacBinary format (Eric Fischer, enf@pobox.com)
> #
> # Unfortunately MacBinary doesn't really have a magic number prior
> # to the MacBinary III format.  The checksum is really the way to
> # do it, but the magic file format isn't up to the challenge.
> #

	Correct, which is why we solved that in MacBinary III...

> # This attempts to use the version numbers as a magic number, requiring
> # that the first one be 0x80, 0x81, 0x82, or 0x83, and that the second
> # be 0x81.  This works for the files I have, but maybe not for everyone's.

	The checksum, the version number and a few other things are 
the common way to determine MacBinary header presense.



> Using that second matching method gets me:
> humbug:~% file -m tmp/magic image.bin
> file: Using regular magic file `tmp/magic'
> image.bin: Macintosh MacBinary data, type "    ", creator "    "
>
> Hah!

	Trust me, this is NOT a MacBinary encoded file!!


> Did you transfer it using binary or ascii mode? (The latter will
> break that file, if it's really a MacBinary I file. That's what
> BinHex and UUEncode are for.)

	BinHex actually incorporates MacBinary-like encoding as part 
of the process - so BinHexing a MacBinary file is silly...


> He's opening it because jpegViewer is doing on-the-fly decompression
> of the MacBinary I format.

	Nope, because it doesn't do that...


Leonard
Chairman, MacBinary III Committee
--
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Leonard Rosenthol                            <mailto:leonardr@lazerware.com>
                     			     <http://www.lazerware.com>
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