Subject:
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Re: MPD Question...
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Newsgroups:
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lugnet.cad.dev
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Date:
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Sat, 20 Mar 1999 07:06:35 GMT
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Viewed:
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796 times
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Ben Bennett wrote:
>
> I searched through the archives of this group and could not find a definitive
> definition of the MPD format (there were several contradictory postings).
Well, here's my impression of the lastest discussion.
> So if someone can answer the following that would be great:
> 1) Which part is assumed to be the start in an MPD if there are multiple
> parts in a file.
The first file in an MPD file is the one that gets drawn.
> 2) Do _valid_ leading lines get ignored? i.e. if I have a part reference
> first, should it get drawn or ignored (this is related to Q1)
_valid_ leading lines are technically an error. There should be no
lines
before the first "0 FILE" except comment lines which begin with "0".
If you do put valid lines before the first "0 FILE", they will probably
get drawn and then erased, and possibly screw up your image.
On the practical side, you can expect most tools to gracefully handle
such errors, including comment lines that do not begin with a "0",
such as the header lines commonly found in a news posting or email
message.
> 3) Is there any way to mark the end of an MPD? (i.e. prior to a sig)
No.
> 4) Is it valid to refer to a part that is later in the MPD?
Yes.
> I think the following is correct:
> 1) Ignore leading lines up to the first '0 File ' line
Unfortunately, MPD files have the same .dat extension as non-MPD files,
so there
is no way for a tool to know in advance the file is an MPD. So it
doesn't
know it was supposed to ignore a line until it is too late. The only
fix for this
is to require tools to scan the file in two passes, once just to see if
"0 FILE"
shows up anywhere, which is too great of a performance hit.
> 2) Extract all '0 File ' pieces into somewhere that will be first in the path
> when looking for files
Often, the files do not actually end up on disk anywhere. LDLite only
keeps
a copy in memory, although this currently puts a limit on the file size
you can use with an MPD, but that needs to change.
>
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Message has 1 Reply:
 | | Re: MPD Question...
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| (...) i'm a little unclear on this point, gyug... .MPD files have the same .DAT extension???? perhaps you mean when posting to LUGNET??? because all of the .MPD's i've DL'd from people's sites... and even MPD's built with my M-Peedy program have (...) (26 years ago, 20-Mar-99, to lugnet.cad.dev)
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Message is in Reply To:
| | MPD Question...
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| I searched through the archives of this group and could not find a definitive definition of the MPD format (there were several contradictory postings). So if someone can answer the following that would be great: 1) Which part is assumed to be the (...) (26 years ago, 19-Mar-99, to lugnet.cad.dev)
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