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From: glenn@heaven.woodside.ca.us (Glenn Reid)
Newsgroups: comp.lang.postscript
Subject: Re: PostScript page counter?
Message-ID: <226@heaven.woodside.ca.us>
Date: 31 Jul 90 01:00:14 GMT
References: <1990Jul26.173633.13911@msuinfo.cl.msu.edu> <1990Jul30.153325.15342@zoo.toronto.edu> <1990Jul30.181713.29483@phri.nyu.edu> <6988@helios.TAMU.EDU>
Reply-To: glenn@heaven.UUCP (Glenn Reid)
Organization: Skyline Press, Woodside CA
Lines: 50

In article <6988@helios.TAMU.EDU> skdutta@cs.tamu.edu (Saumen K Dutta) writes:
>If you think there could be problems with the %Pages in postscript
>file due no non-conformance of standards or suspecting malicious
>intent you could also check up for the control character ^L in the
>postscript file which is usually used for pagebreak

In five years of looking at PostScript files I have never seen a control-L
character embedded in a file, nor should they be.  What application or
system do you use such that a ^L is "usually used for pagebreak," out
of curiosity?

I can't say I'd recommend that technique, although I guess it can't hurt
to look for ^L.

I have a feeling there is a midway-point between the "you can't count
pages without an interpreter" answer and the "just look at the %%Pages
comment" answers, although I'll admit that I haven't actually tried
it.

In reality, almost every PostScript driver defines some procedure in the
prologue the file called "EndPage" or "EP" or "SP" or whatever, and
there is one invocation of that procedure for each page printed.  With
a moderately simple parser, it should be possible to figure out the
name of the procedure that contains "showpage" in it somewhere, then
go looking for instances of that procedure name in the rest of the
document.  Example:

	/BP { /page_save save def } def		% begin-page
	/EP { page_save restore showpage } def	% end-page
	 ...
	BP
	 % lots of stuff
	EP

Any volunteers to write the simple parser?  If it can recognize the
basic syntax

	/name { { stuff } }

I suspect that you could find the procedure that contained "showpage"
fairly easily.  Any volunteers?  Want to endear yourself to the
PostScript community with a great page-counting program?  [ Want to
earn real $$ in your spare time sharpening saw blades? ]

(Glenn) cvn

-- 
 Glenn Reid				PostScript/NeXT consultant
 glenn@heaven.woodside.ca.us		Independent Software Developer
 ..{adobe,next}!heaven!glenn		415-851-1785