Bug 1268

Summary:	magic match offset and value enhancements
Product:	shared-mime-info	Reporter:	Filip Van Raemdonck <mechanix>
Component:	general	Assignee:	Jonathan Blandford <jrb>
Status:	RESOLVED FIXED	QA Contact:
Severity:	enhancement
Priority:	high	CC:	bugzilla
Version:	unspecified
Hardware:	x86 (IA32)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Filip Van Raemdonck 2004-09-01 05:42:54 UTC

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=245262 talks about
mis-detection of Truevision Targa files.
Googling around for an identifier finds some specifications:
http://netghost.narod.ru/gff/graphics/summary/tga.htm
http://www.dcs.ed.ac.uk/home/mxr/gfx/2d/Targa.ps
http://astronomy.swin.edu.au/~pbourke/dataformats/tga/
http://www.ludorg.net/amnesia/TGA_File_Format_Spec.html

And one actual magic file with a targa pattern:
http://www.alaska.net/~royce/pub/solaris/MAGIC

Reading those specifications and examining the magic pattern, the current
shared-mime-info match element clearly is insufficient to describe the targa
magic without duplicating a lot of nested match patterns. This would be avoided
if the match patterns would support (as file(1) magic does) '<' or '>'
constructs for the value of it's value attribute.

Second, version2 targa files can be recognized by their last 18 bytes being the
string 'TRUEVISION-XFILE.\0', according to
http://www.bergen.org/AAST/ComputerAnimation/Help_FAQs_File4.html

AFAICS, it is also not possible to specify a negative offset from the
end-of-file for a match. This too limits the usefulness of the match element.

Comment 1 Bastien Nocera 2007-02-05 07:49:46 UTC

The proper magic in Targa files is at the end of the file, not at the beginning:
http://www.ludorg.net/amnesia/TGA_File_Format_Spec.html

So it's easier just removing the bogus magic, and rely solely on the suffix instead.

2007-02-05  Bastien Nocera  <hadess@hadess.net>

        * freedesktop.org.xml.in: Remove the TGA mime magic as it was bogus, and
        the real Targa magic is at the end of the file, not at the beginning
        (Closes: #1268)

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