#	$OpenBSD: jpeg,v 1.4 2009/04/24 18:54:34 chl Exp $

#------------------------------------------------------------------------------
# JPEG images
# SunOS 5.5.1 had
#
#	0	string		\377\330\377\340	JPEG file
#	0	string		\377\330\377\356	JPG file
#
# both of which turn into "JPEG image data" here.
#
0	string	\xff\xd8\xff	JPEG image
>6	string	JFIF		, JFIF standard
>6	string	Exif		, EXIF standard

#  0	beshort		0xffd8
#  !:mime	image/jpeg
#  >6	string		JFIF		JPEG image data\b, JFIF standard
#  # The following added by Erik Rossen <rossen@freesurf.ch> 1999-09-06
#  # in a vain attempt to add image size reporting for JFIF.  Note that these
#  # tests are not fool-proof since some perfectly valid JPEGs are currently
#  # impossible to specify in magic(4) format.
#  # First, a little JFIF version info:
#  >>11	byte		x		\b %d.
#  >>12	byte		x		\b%02d
#  # Next, the resolution or aspect ratio of the image:
#  #>>13	byte		0		\b, aspect ratio
#  #>>13	byte		1		\b, resolution (DPI)
#  #>>13	byte		2		\b, resolution (DPCM)
#  #>>4	beshort		x		\b, segment length %d
#  # Next, show thumbnail info, if it exists:
#  >>18	byte		!0		\b, thumbnail %dx
#  >>>19	byte		x		\b%d
#  
#  # EXIF moved down here to avoid reporting a bogus version number,
#  # and EXIF version number printing added.
#  #   - Patrik R=E5dman <patrik+file-magic@iki.fi>
#  >6	string		Exif		JPEG image data\b, EXIF standard
#  # Look for EXIF IFD offset in IFD 0, and then look for EXIF version tag in EXIF IFD.
#  # All possible combinations of entries have to be enumerated, since no looping
#  # is possible. And both endians are possible...
#  # The combinations included below are from real-world JPEGs.
#  # Little-endian
#  >>12	string		II		
#  # IFD 0 Entry #5:
#  >>>70	leshort		0x8769          
#  # EXIF IFD Entry #1:
#  >>>>(78.l+14)	leshort	0x9000		
#  >>>>>(78.l+23)	byte	x		%c
#  >>>>>(78.l+24)	byte	x		\b.%c
#  >>>>>(78.l+25)	byte	!0x30		\b%c
#  # IFD 0 Entry #9:
#  >>>118	leshort		0x8769          
#  # EXIF IFD Entry #3:
#  >>>>(126.l+38)	leshort	0x9000		
#  >>>>>(126.l+47)	byte	x		%c
#  >>>>>(126.l+48)	byte	x		\b.%c
#  >>>>>(126.l+49)	byte	!0x30		\b%c
#  # IFD 0 Entry #10
#  >>>130	leshort		0x8769          
#  # EXIF IFD Entry #3:
#  >>>>(138.l+38)	leshort	0x9000		
#  >>>>>(138.l+47)	byte	x		%c
#  >>>>>(138.l+48)	byte	x		\b.%c
#  >>>>>(138.l+49)	byte	!0x30		\b%c
#  # EXIF IFD Entry #4:
#  >>>>(138.l+50)	leshort	0x9000		
#  >>>>>(138.l+59)	byte	x		%c
#  >>>>>(138.l+60)	byte	x		\b.%c
#  >>>>>(138.l+61)	byte	!0x30		\b%c
#  # EXIF IFD Entry #5:
#  >>>>(138.l+62)	leshort	0x9000		
#  >>>>>(138.l+71)	byte	x		%c
#  >>>>>(138.l+72)	byte	x		\b.%c
#  >>>>>(138.l+73)	byte	!0x30		\b%c
#  # IFD 0 Entry #11
#  >>>142	leshort		0x8769          
#  # EXIF IFD Entry #3:
#  >>>>(150.l+38)	leshort	0x9000		
#  >>>>>(150.l+47)	byte	x		%c
#  >>>>>(150.l+48)	byte	x		\b.%c
#  >>>>>(150.l+49)	byte	!0x30		\b%c
#  # EXIF IFD Entry #4:
#  >>>>(150.l+50)	leshort	0x9000		
#  >>>>>(150.l+59)	byte	x		%c
#  >>>>>(150.l+60)	byte	x		\b.%c
#  >>>>>(150.l+61)	byte	!0x30		\b%c
#  # EXIF IFD Entry #5:
#  >>>>(150.l+62)	leshort	0x9000		
#  >>>>>(150.l+71)	byte	x		%c
#  >>>>>(150.l+72)	byte	x		\b.%c
#  >>>>>(150.l+73)	byte	!0x30		\b%c
#  # Big-endian
#  >>12	string		MM		
#  # IFD 0 Entry #9:
#  >>>118	beshort		0x8769          
#  # EXIF IFD Entry #1:
#  >>>>(126.L+14)	beshort	0x9000		
#  >>>>>(126.L+23)	byte	x		%c
#  >>>>>(126.L+24)	byte	x		\b.%c
#  >>>>>(126.L+25)	byte	!0x30		\b%c
#  # EXIF IFD Entry #3:
#  >>>>(126.L+38)	beshort	0x9000		
#  >>>>>(126.L+47)	byte	x		%c
#  >>>>>(126.L+48)	byte	x		\b.%c
#  >>>>>(126.L+49)	byte	!0x30		\b%c
#  # IFD 0 Entry #10
#  >>>130	beshort		0x8769          
#  # EXIF IFD Entry #3:
#  >>>>(138.L+38)	beshort	0x9000		
#  >>>>>(138.L+47)	byte	x		%c
#  >>>>>(138.L+48)	byte	x		\b.%c
#  >>>>>(138.L+49)	byte	!0x30		\b%c
#  # EXIF IFD Entry #5:
#  >>>>(138.L+62)	beshort	0x9000		
#  >>>>>(138.L+71)	byte	x		%c
#  >>>>>(138.L+72)	byte	x		\b.%c
#  >>>>>(138.L+73)	byte	!0x30		\b%c
#  # IFD 0 Entry #11
#  >>>142	beshort		0x8769          
#  # EXIF IFD Entry #4:
#  >>>>(150.L+50)	beshort	0x9000		
#  >>>>>(150.L+59)	byte	x		%c
#  >>>>>(150.L+60)	byte	x		\b.%c
#  >>>>>(150.L+61)	byte	!0x30		\b%c
#  # Here things get sticky.  We can do ONE MORE marker segment with
#  # indirect addressing, and that's all.  It would be great if we could
#  # do pointer arithemetic like in an assembler language.  Christos?
#  # And if there was some sort of looping construct to do searches, plus a few
#  # named accumulators, it would be even more effective...
#  # At least we can show a comment if no other segments got inserted before:
#  >(4.S+5)	byte		0xFE
#  >>(4.S+8)	string		>\0		\b, comment: "%s"
#  #>(4.S+5)	byte		0xFE		\b, comment
#  #>>(4.S+6)	beshort		x		\b length=%d
#  #>>(4.S+8)	string		>\0		\b, "%s"
#  # Or, we can show the encoding type (I've included only the three most common)
#  # and image dimensions if we are lucky and the SOFn (image segment) is here:
#  >(4.S+5)	byte		0xC0		\b, baseline
#  >>(4.S+6)	byte		x		\b, precision %d
#  >>(4.S+7)	beshort		x		\b, %dx
#  >>(4.S+9)	beshort		x		\b%d
#  >(4.S+5)	byte		0xC1		\b, extended sequential
#  >>(4.S+6)	byte		x		\b, precision %d
#  >>(4.S+7)	beshort		x		\b, %dx
#  >>(4.S+9)	beshort		x		\b%d
#  >(4.S+5)	byte		0xC2		\b, progressive
#  >>(4.S+6)	byte		x		\b, precision %d
#  >>(4.S+7)	beshort		x		\b, %dx
#  >>(4.S+9)	beshort		x		\b%d
#  # I've commented-out quantisation table reporting.  I doubt anyone cares yet.
#  #>(4.S+5)	byte		0xDB		\b, quantisation table
#  #>>(4.S+6)	beshort		x		\b length=%d
#  #>14	beshort		x		\b, %d x
#  #>16	beshort		x		\b %d
#  
#  # HSI is Handmade Software's proprietary JPEG encoding scheme
#  #0	string		hsi1		JPEG image data, HSI proprietary
#  
#  # From: David Santinoli <david@santinoli.com>
#  0	string		\x00\x00\x00\x0C\x6A\x50\x20\x20\x0D\x0A\x87\x0A	JPEG 2000 image data
#  
#  # Type: JPEG 2000 codesream
#  # From: Mathieu Malaterre <mathieu.malaterre@gmail.com>
#  0	belong		0xff4fff51						JPEG 2000 codestream
#  45	beshort		0xff52
