Hello trid users,
some days ago i run TrID with verbose option on eXtensible ARchives.
( see appended output/trid-v-old.txt).
All are recognized by definition ark-xar.trid.xml.
In old trid definition an URL on File Format website was
used. Unfortunately there exist more formats with "xar" extension like
Xara vector graphics. So the used link is not unique enough. But on
website a link to Xar (Extensible Archive) exist. So use now that URL as
reference by line:
<RefURL>
http://fileformats.archiveteam.org/wiki/Xar_(Extensible_Archive)
</RefURL>
There also a Wikipedia article about xar (archiver) is mentioned.
In old definition mime type is "application/octet-stream". According to
Wikipedia eXtensible ARchives get their own mime type. This is now
expressed by line:
<Mime>application/x-xar</Mime>
In old definition only start magic xar! is used as pattern. So ASCII
text starting with that phrase like sample xar-exclamation.txt are
misidentified as EXtensible ARchives. So add some null pattern to
exclude ASCII text and keep only binary XARs. So i use unused upper byte
of version field, which is at the moment only 1. This is expressed by
XML-construct:
<Bytes>00</Bytes>
<Pos>6</Pos>
In old definition only filename extension "xar" is mentioned. The xar
format is used by some Mac OS X installers for packages. Then there the
filename extension "pkg" like in example FullBundleUpdate.pkg is
used. Apple introduced a variant with additional signature. Such signed
archives like Xcode_10.2_beta_4.xip have "xip" extension. So these 3
extensions are shown by updated line:
<Ext>XAR/PKG/XIP</Ext>
With the updated trid definition all eXtensible ARchivers are now
described ( see appended output/trid-v-new.txt) more precisely also with
mime type. TrID definitions, some samples and output are stored in
archive xar_trid.zip. I hope that my XML file can be used in future
version of triddefs.
With best wishes
J?rg Jenderek
