Added ASTC texture format detection. (David Korth)

diff --git a/magic/Magdir/images b/magic/Magdir/images
index c9cf754be7bb19184a4105ab11b716a526a8fee9..b03d83e9568ae01486acb376e3bf75fc1d5a3ff3 100644 (file)
--- a/magic/Magdir/images
+++ b/magic/Magdir/images
@@ -1,6 +1,6 @@
 
 #------------------------------------------------------------------------------
-# $File: images,v 1.140 2018/06/23 16:38:52 christos Exp $
+# $File: images,v 1.141 2018/06/23 16:39:21 christos Exp $
 # images:  file(1) magic for image formats (see also "iff", and "c-lang" for
 # XPM bitmaps)
 #
@@ -1658,3 +1658,18 @@
 >0x16  beshort         x       \b x %u
 >0x10  belong&0x2000   0       \b, DXT1
 >0x10  belong&0x2000   0x2000  \b, DXT5
+
+# Type: ASTC texture.
+# From: David Korth <gerbilsoft@gerbilsoft.com>
+# References:
+# - https://stackoverflow.com/questions/22600678/determine-internal-format-of-given-astc-compressed-image-through-its-header
+# - https://stackoverflow.com/a/22682244
+0      lelong  0x5ca1ab13                      ASTC
+>4     byte    x                               %u
+>5     byte    x                               \bx%u
+>6     byte    >1                              \bx%u
+# X, Y, and Z dimensions are stored as 24-bit LE.
+# Pretend it's 32-bit and mask off the high byte.
+>7     lelong&0x00FFFFFF       x               texture, %u
+>10    lelong&0x00FFFFFF       x               x %u
+>13    lelong&0x00FFFFFF       >1              x %u