better g3 fax detection Joerg Jenderek

diff --git a/magic/Magdir/modem b/magic/Magdir/modem
index 7673f9bd252b7b7cb026fde1c378e6ac1d17c5f8..bd4099cb1b438f9ccb24e07c220b3e5f8bb6e55d 100644 (file)
--- a/magic/Magdir/modem
+++ b/magic/Magdir/modem
@@ -1,6 +1,6 @@
 
 #------------------------------------------------------------------------------
-# $File: modem,v 1.5 2010/09/20 18:55:20 rrt Exp $
+# $File: modem,v 1.6 2015/02/14 17:35:47 christos Exp $
 # modem:  file(1) magic for modem programs
 #
 # From: Florian La Roche <florian@knorke.saar.de>
@@ -8,8 +8,48 @@
 >29    byte            1                       \b, fine resolution
 >29    byte            0                       \b, normal resolution
 
-0      short           0x0100          raw G3 data, byte-padded
-0      short           0x1400          raw G3 data
+# Summary: CCITT Group 3 Facsimile in "raw" form (i.e. no header).
+# Modified by: Joerg Jenderek
+# URL: https://de.wikipedia.org/wiki/Fax
+# Reference: http://web.archive.org/web/20020628195336/http://www.netnam.vn/unescocourse/computervision/104.htm
+# GRR: EOL of G3 is too general as it catches also TrueType fonts, Postscript PrinterFontMetric, others
+0      short           0x0100          
+# 16 0-bits near beginning like True Type fonts *.ttf, Postscript PrinterFontMetric *.pfm, FTYPE.HYPERCARD, XFER
+>2     search/9        \0\0            
+# maximal 7 0-bits for pixel sequences or 11 0-bits for EOL in G3
+>2     default         x               
+# skip IRCAM file (VAX big-endian)     ./audio
+>>0    belong          !0x0001a364     
+# skip GEM Image data                  ./images
+>>>2   beshort         !0x0008         
+# look for first keyword of Panorama database *.pan
+>>>>11 search/262      \x06DESIGN      
+# skip Panorama database
+>>>>11 default         x               
+# old Apple DreamWorld DreamGrafix *.3200 with keyword at end of g3 looking files
+>>>>>27118     search/1864     DreamWorld      
+>>>>>27118     default         x               
+# skip MouseTrap/Mt.Defaults with file size 16 found on Golden Orchard Apple II CD Rom
+>>>>>>8                ubequad         !0x2e01010454010203     
+# skip PICTUREH.SML found on Golden Orchard Apple II CD Rom
+>>>>>>>8       ubequad         !0x5dee74ad1aa56394     raw G3 (Group 3) FAX, byte-padded
+# version 5.25 labeled the entry above "raw G3 data, byte-padded"
+!:mime image/g3fax
+#!:apple       ????TIFF
+!:ext  g3
+# unusual image starting with black pixel
+#0     short           0x1300          raw G3 (Group 3) FAX
+0      short           0x1400          
+# 16 0-bits near beginning like PicturePuzzler found on Golden Orchard Apple CD Rom
+>2     search/9        \0\0            
+# maximal 7 0-bits for pixel sequences or 11 0-bits for EOL in G3
+>2     default         x               raw G3 (Group 3) FAX
+# version 5.25 labeled the above entry as "raw G3 data"
+!:mime image/g3fax
+!:ext  g3
+# unusual image with black pixel near beginning
+#0     short           0x1900          raw G3 (Group 3) FAX
+
 #
 # Magic data for vgetty voice formats
 # (Martin Seine & Marc Eberhard)