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Groups > alt.folklore.computers > #235572
| From | "Carlos E. R." <robin_listas@es.invalid> |
|---|---|
| Newsgroups | alt.folklore.computers |
| Subject | Re: Question re postscript and pdf |
| Date | 2026-09-11 14:42 +0200 |
| Message-ID | <ngiba0Fec7fU2@mid.individual.net> (permalink) |
| References | <dl7bnmxdr4.ln2@Telcontar.valinor> <1180rto$2smu7$1@dont-email.me> |
On 2026-09-11 14:24, magardner2010 wrote:
> On 10/09/2026 20:57, Carlos E.R. wrote:
> > [...] I know that it is
> > trivial to convert from ps to pdf. [...]
>
> To my understanding, it's actually the other way round. PDF is, or at
> least was, a wrapper format around a subset of postscript. To get
> equivalent postscript, you just need to unwrap the postscript, and give
> it the extra stuff the pdf contains (like images or fonts) in a way it
> understands. To convert arbitrary postscript into a PDF, you need to
> rewrite the postscript to only use the non Turing-complete subset
> allowed in pdf, which I could see running into the halting problem and
> other fun stuff. However, once you do have the final result of the
> postscript execution, the pdf wrapping is indeed quite simple, with the
> most complicated bit being the cross-reference index that is "just"
> counting how many bytes away each object is from the beginning of the file.
>
> > It also occurs to me to ask what is the advantage for printers of
> > talking pdf instead of ps.
>
> The big one I know is that PDF is not Turing complete, while PS is. You
> don't want your printer running infinite loops or memory bombs or
> similar. A malicious postscript document doesn't need a buggy postscript
> interpreter to do it's dirty work, a malicious pdf needs to cause the
> interpreter to misbehave to do any damage.
Oh, that's interesting.
--
Cheers,
Carlos E.R.
ES🇪🇸, EU🇪🇺.
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Question re postscript and pdf "Carlos E.R." <robin_listas@es.invalid> - 2026-09-10 19:57 +0200
Re: Question re postscript and pdf usenet@spuddy.org (Stephen Harris) - 2026-09-11 08:09 -0400
Re: Question re postscript and pdf "Carlos E. R." <robin_listas@es.invalid> - 2026-09-11 14:44 +0200
Re: Question re postscript and pdf magardner2010 <magardner2010@gmail.com> - 2026-09-11 15:24 +0300
Re: Question re postscript and pdf "Carlos E. R." <robin_listas@es.invalid> - 2026-09-11 14:42 +0200
Re: Question re postscript and pdf Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-12 02:21 +0000
Re: Question re postscript and pdf Ian <${send-direct-email-to-news1021-at-jusme-dot-com-if-you-must}@jusme.com> - 2026-09-12 07:32 +0000
Re: Question re postscript and pdf Nuno Silva <nunojsilva@invalid.invalid> - 2026-09-12 11:07 +0100
Re: Question re postscript and pdf "Carlos E.R." <robin_listas@es.invalid> - 2026-09-12 13:20 +0200
Re: Question re postscript and pdf Nuno Silva <nunojsilva@invalid.invalid> - 2026-09-12 12:52 +0100
Re: Question re postscript and pdf Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-13 08:16 +0000
Re: Question re postscript and pdf "Carlos E.R." <robin_listas@es.invalid> - 2026-09-13 13:42 +0200
Re: Question re postscript and pdf James Dow Allen <user4353@newsgrouper.org.invalid> - 2026-09-13 13:03 +0000
Re: Question re postscript and pdf Peter Flass <Peter@Iron-Spring.com> - 2026-09-13 07:33 -0700
Re: Question re postscript and pdf John Levine <johnl@taugh.com> - 2026-09-13 14:50 +0000
Re: Question re postscript and pdf "Carlos E.R." <robin_listas@es.invalid> - 2026-09-13 19:09 +0200
Re: Question re postscript and pdf antispam@fricas.org (Waldek Hebisch) - 2026-09-14 16:22 +0000
Re: Question re postscript and pdf Nuno Silva <nunojsilva@invalid.invalid> - 2026-09-15 10:41 +0100
Re: Question re postscript and pdf Peter Flass <Peter@Iron-Spring.com> - 2026-09-15 07:41 -0700
Re: Question re postscript and pdf Nuno Silva <nunojsilva@invalid.invalid> - 2026-09-16 00:23 +0100
Re: Question re postscript and pdf Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-15 23:25 +0000
Re: Question re postscript and pdf Dave Yeo <dave.r.yeo@gmail.com> - 2026-09-15 20:07 -0700
Re: Question re postscript and pdf Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-16 04:17 +0000
Re: Question re postscript and pdf Nuno Silva <nunojsilva@invalid.invalid> - 2026-09-16 11:41 +0100
Re: Question re postscript and pdf Peter Flass <Peter@Iron-Spring.com> - 2026-09-16 08:02 -0700
Re: Question re postscript and pdf Dave Yeo <dave.r.yeo@gmail.com> - 2026-09-16 14:41 -0700
Re: Question re postscript and pdf Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-17 01:56 +0000
Re: Question re postscript and pdf Nuno Silva <nunojsilva@invalid.invalid> - 2026-09-17 10:27 +0100
About OO vs LO "Carlos E. R." <robin_listas@es.invalid> - 2026-09-16 09:19 +0200
Re: About OO vs LO Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-16 07:48 +0000
Re: About OO vs LO "Carlos E. R." <robin_listas@es.invalid> - 2026-09-16 11:57 +0200
Re: Question re postscript and pdf Peter Flass <Peter@Iron-Spring.com> - 2026-09-16 07:55 -0700
Re: Question re postscript and pdf Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2026-09-16 16:22 +0000
Re: Question re postscript and pdf Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-17 01:57 +0000
Re: Question re postscript and pdf Chris Ahlstrom <OFeem1987@teleworm.us> - 2026-09-18 17:35 -0400
Re: Question re postscript and pdf Nuno Silva <nunojsilva@invalid.invalid> - 2026-09-12 10:59 +0100
Re: Question re postscript and pdf antispam@fricas.org (Waldek Hebisch) - 2026-09-14 16:08 +0000
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