Subject: Re: [netatalk-admins] papd problem - never closes
From: Andras Kadinger (bandit@freeside.elte.hu)
Date: Thu May 28 1998 - 18:21:07 EDT
Les, Wesley,
Les Klein wrote:
>
> Wesley Craig wrote:
> >
> > This is a short-coming in papd. I have a work-around (implemented to
> > work around bugs in Desktop printing), but it "corrupts" the input as
> > above. I say "corrupts", because your input stream is clearly already
> > corrupted if you have a dangling '\004'. What driver are you using
> > that thinks it ought to send an EOT character on a PAP stream? That's
> > clearly way out of spec. PAP is expecting PostScript Document
> > Structure Convention compliant files. DSC is pretty much line
> > oriented, and pretty much states that the end-of-line character isn't
> > important. Unless you're supporting binary, which papd doesn't. If it
> > did, it would still only be supported inside DSC comments that
> > indicated the binary section.
> >
> That's OK so why can't papd do this (look for %%Begin Binary)?
Well, with the routines I sent to You this problem can easily be
overcome, and You can get fully transparent binary stream handling,
while retaining the 'line-orientedness' needed for DSC comment handling.
The %%BeginBinary (or, as the more recent DSC 3.0 suggests, %%BeginData,
but apparently noone really uses that) convention might really be a win
if You process large amounts of binary PostScript data; unfortunately,
there are existing implementations blindly spitting out '%%BeginBinary:
1' regardless of the actual amount of data as well as outputting Type1
font definitions in binary (they should be ASCII unless the environment
is 'well-controlled'). These issues seem to indicate that full binary
transparency is easier to do, than trying to parse and trust comments.
The approach I found to be the best was to take the
%%BeginBinary/%%BeginData comment as a hint to speed up processing, and
then just to prevent things from breaking, read up to the next
%%EndBinary/%%EndData - although this measure becomes unnecessary when
being really binary-transparent. The worst case in this scenario would
be misinterpreting some reasonably comment-like sequences in the binary
data.
As of broken drivers: unfortunately, the newest generation of LW drivers
seem to provide an 'ascii/binary PostScript' option...
Les, You seem to be working in the DTP area just as me. I would gladly
cooperate.
Wesley, look, here comes the first of the projects! :-)
Sincerely,
Andras Kadinger
bandit@freeside.elte.hu
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