images

UNIX下FILE命令的实现源码

#------------------------------------------------------------------------------
# images:  file(1) magic for image formats (see also "iff")
#
# originally from [e-mail] (Jef Poskanzer),
# additions by [e-mail] as well as others. Jan also suggested
# merging several one- and two-line files into here.
#
# little magic: PCX (first byte is 0x0a)

# Targa - matches `povray', `ppmtotga' and `xv' outputs
# by Philippe De Muyter <[e-mail]>
# at 2, byte ImgType must be 1, 2, 3, 9, 10 or 11
# at 1, byte CoMapType must be 1 if ImgType is 1 or 9, 0 otherwise
# at 3, leshort Index is 0 for povray, ppmtotga and xv outputs
# `xv' recognizes only a subset of the following (RGB with pixelsize = 24)
# `tgatoppm' recognizes a superset (Index may be anything)
1	belong&0xfff7ffff	0x01010000	Targa image data - Map
>2	byte&8			8		- RLE
1	belong&0xfff7ffff	0x00020000	Targa image data - RGB
>2	byte&8			8		- RLE
1	belong&0xfff7ffff	0x00030000	Targa image data - Mono
>2	byte&8			8		- RLE

# PBMPLUS images
# The next byte following the magic is always whitespace.
0	string		P1		Netpbm PBM image text
0	string		P2		Netpbm PGM image text
0	string		P3		Netpbm PPM image text
0	string		P4		Netpbm PBM "rawbits" image data
0	string		P5		Netpbm PGM "rawbits" image data
0	string		P6		Netpbm PPM "rawbits" image data
0	string		P7		Netpbm PAM image file

# From: [e-mail] (Bryan Henderson)
0	string		\117\072	Solitaire Image Recorder format
>4	string		\013		MGI Type 11
>4	string		\021		MGI Type 17
0	string		.MDA		MicroDesign data
>21	byte		48		version 2
>21	byte		51		version 3
0	string		.MDP		MicroDesign page data
>21	byte		48		version 2
>21	byte		51		version 3

# NIFF (Navy Interchange File Format, a modification of TIFF) images
0	string		IIN1		NIFF image data

# Tag Image File Format, from Daniel Quinlan ([e-mail])
# The second word of TIFF files is the TIFF version number, 42, which has
# never changed.  The TIFF specification recommends testing for it.
0	string		MM\x00\x2a	TIFF image data, big-endian
0	string		II\x2a\x00	TIFF image data, little-endian

# PNG [Portable Network Graphics, or "PNG's Not GIF"] images
# (Greg Roelofs, [e-mail])
# (Albert Cahalan, [e-mail])
#
# 137 P N G \r \n ^Z \n [4-byte length] H E A D [HEAD data] [HEAD crc] ...
#
0	string		\x89PNG		PNG image data,
>4	belong		!0x0d0a1a0a	CORRUPTED,
>4	belong		0x0d0a1a0a
>>16	belong		x		%ld x
>>20	belong		x		%ld,
>>24	byte		x		%d-bit
>>25	byte		0		grayscale,
>>25	byte		2		\b/color RGB,
>>25	byte		3		colormap,
>>25	byte		4		gray+alpha,
>>25	byte		6		\b/color RGBA,
#>>26	byte		0		deflate/32K,
>>28	byte		0		non-interlaced
>>28	byte		1		interlaced
1	string		PNG		PNG image data, CORRUPTED

# GIF
0	string		GIF8		GIF image data
>4	string		7a		\b, version 8%s,
>4	string		9a		\b, version 8%s,
>6	leshort		>0		%hd x
>8	leshort		>0		%hd,
#>10	byte		&0x80		color mapped,
#>10	byte&0x07	=0x00		2 colors
#>10	byte&0x07	=0x01		4 colors
#>10	byte&0x07	=0x02		8 colors
#>10	byte&0x07	=0x03		16 colors
#>10	byte&0x07	=0x04		32 colors
#>10	byte&0x07	=0x05		64 colors
#>10	byte&0x07	=0x06		128 colors
#>10	byte&0x07	=0x07		256 colors

# ITC (CMU WM) raster files.  It is essentially a byte-reversed Sun raster,
# 1 plane, no encoding.
0	string		\361\0\100\273	CMU window manager raster image data
>4	lelong		>0		%d x
>8	lelong		>0		%d,
>12	lelong		>0		%d-bit

# Magick Image File Format
0	string		id=ImageMagick	MIFF image data

# Artisan
0	long		1123028772	Artisan image data
>4	long		1		\b, rectangular 24-bit
>4	long		2		\b, rectangular 8-bit with colormap
>4	long		3		\b, rectangular 32-bit (24-bit with matte)

# FIG (Facility for Interactive Generation of figures), an object-based format
0	string		#FIG		FIG image text
>5	string		x		\b, version %.3s

# PHIGS
0	string		ARF_BEGARF		PHIGS clear text archive
0	string		@(#)SunPHIGS		SunPHIGS
# version number follows, in the form m.n
>40	string		SunBin			binary
>32	string		archive			archive

# GKS (Graphics Kernel System)
0	string		GKSM		GKS Metafile
>24	string		SunGKS		\b, SunGKS

# CGM image files
0	string		BEGMF		clear text Computer Graphics Metafile
# XXX - questionable magic
0	beshort&0xffe0	0x0020		binary Computer Graphics Metafile
0	beshort		0x3020		character Computer Graphics Metafile

# MGR bitmaps  (Michael Haardt, [e-mail])
0	string	yz	MGR bitmap, modern format, 8-bit aligned
0	string	zz	MGR bitmap, old format, 1-bit deep, 16-bit aligned
0	string	xz	MGR bitmap, old format, 1-bit deep, 32-bit aligned
0	string	yx	MGR bitmap, modern format, squeezed

# Fuzzy Bitmap (FBM) images
0	string		%bitmap\0	FBM image data
>30	long		0x31		\b, mono
>30	long		0x33		\b, color

# facsimile data
1	string		PC\ Research,\ Inc	group 3 fax data
>29	byte		0		\b, normal resolution (204x98 DPI)
>29	byte		1		\b, fine resolution (204x196 DPI)

# PC bitmaps (OS/2, Windoze BMP files)  (Greg Roelofs, [e-mail])
0	string		BM		PC bitmap data
>14	leshort		12		\b, OS/2 1.x format
>>18	leshort		x		\b, %d x
>>20	leshort		x		%d
>14	leshort		64		\b, OS/2 2.x format
>>18	leshort		x		\b, %d x
>>20	leshort		x		%d
>14	leshort		40		\b, Windows 3.x format
>>18	lelong		x		\b, %d x
>>22	lelong		x		%d x
>>28	leshort		x		%d
0	string		IC		PC icon data
0	string		PI		PC pointer image data
0	string		CI		PC color icon data
0	string		CP		PC color pointer image data
# Conflicts with other entries [BABYL]
#0	string		BA		PC bitmap array data

# XPM icons (Greg Roelofs, [e-mail])
# note possible collision with C/REXX entry in c-lang; currently commented out
0	string		/*\ XPM\ */	X pixmap image text

# Utah Raster Toolkit RLE images ([e-mail])
0	leshort		0xcc52		RLE image data,
>6	leshort		x		%d x
>8	leshort		x		%d
>2	leshort		>0		\b, lower left corner: %d
>4	leshort		>0		\b, lower right corner: %d
>10	byte&0x1	=0x1		\b, clear first
>10	byte&0x2	=0x2		\b, no background
>10	byte&0x4	=0x4		\b, alpha channel
>10	byte&0x8	=0x8		\b, comment
>11	byte		>0		\b, %d color channels
>12	byte		>0		\b, %d bits per pixel
>13	byte		>0		\b, %d color map channels

# image file format (Robert Potter, [e-mail])
0	string		Imagefile\ version-	iff image data
# this adds the whole header (inc. version number), informative but longish
>10	string		>\0		%s

# Sun raster images, from Daniel Quinlan ([e-mail])
0	belong		0x59a66a95	Sun raster image data
>4	belong		>0		\b, %d x
>8	belong		>0		%d,
>12	belong		>0		%d-bit,
#>16	belong		>0		%d bytes long,
>20	belong		0		old format,
#>20	belong		1		standard,
>20	belong		2		compressed,
>20	belong		3		RGB,
>20	belong		4		TIFF,
>20	belong		5		IFF,
>20	belong		0xffff		reserved for testing,
>24	belong		0		no colormap
>24	belong		1		RGB colormap
>24	belong		2		raw colormap
#>28	belong		>0		colormap is %d bytes long

# SGI image file format, from Daniel Quinlan ([e-mail])
#
# See
#	http://reality.sgi.com/grafica/sgiimage.html
#
0	beshort		474		SGI image data
#>2	byte		0		\b, verbatim
>2	byte		1		\b, RLE
#>3	byte		1		\b, normal precision
>3	byte		2		\b, high precision
>4	beshort		x		\b, %d-D
>6	beshort		x		\b, %d x
>8	beshort		x		%d
>10	beshort		x		\b, %d channel
>10	beshort		!1		\bs
>80	string		>0		\b, "%s"

0	string		IT01		FIT image data
>4	belong		x		\b, %d x
>8	belong		x		%d x
>12	belong		x		%d
#
0	string		IT02		FIT image data
>4	belong		x		\b, %d x
>8	belong		x		%d x
>12	belong		x		%d
#
2048	string		PCD_IPI		Kodak Photo CD image pack file
0	string		PCD_OPA		Kodak Photo CD overview pack file

# FITS format.  Jeff Uphoff <[e-mail]>
# FITS is the Flexible Image Transport System, the de facto standard for
# data and image transfer, storage, etc., for the astronomical community.
# (FITS floating point formats are big-endian.)
0	string	SIMPLE\ \ =	FITS image data
>109	string	8		\b, 8-bit, character or unsigned binary integer
>108	string	16		\b, 16-bit, two's complement binary integer
>107	string	\ 32		\b, 32-bit, two's complement binary integer
>107	string	-32		\b, 32-bit, floating point, single precision
>107	string	-64		\b, 64-bit, floating point, double precision

# other images
0	string	This\ is\ a\ BitMap\ file	Lisp Machine bit-array-file
0	string		!!		Bennet Yee's "face" format

# From SunOS 5.5.1 "/etc/magic" - appeared right before Sun raster image
# stuff.
#
0	beshort		0x1010		PEX Binary Archive

# Visio drawings
03000	string	Visio\ (TM)\ Drawing	%s

# Tgif files
0	string	\%TGIF\ x 		Tgif file version %s

# DICOM medical imaging data
128	string	DICM			DICOM medical imaging data

# XWD - X-Windows Dump file.
#   As described in /usr/X11R6/include/X11/XWDFile.h
#   used by the xwd program.
#   Bradford Castalia, idaeim, 1/01
4	belong	7			XWD X-Widows Dump image data
>100	string	>\0			\b, "%s"
>16	belong	x			\b, %dx
>20	belong	x			\b%dx
>12	belong	x			\b%d

# PDS - Planetary Data System
#   These files use Parameter Value Language in the header section.
#   Unfortunately, there is no certain magic, but the following
#   strings have been found to be most likely.
0	string	NJPL1I00		PDS (JPL) image data
2	string	NJPL1I			PDS (JPL) image data
0	string	CCSD3ZF			PDS (CCSD) image data
2	string	CCSD3Z			PDS (CCSD) image data
0	string	PDS_			PDS image data
0	string	LBLSIZE=		PDS (VICAR) image data

0	string		GSTIm		GNU SmallTalk image file

# pM8x: ATARI STAD compressed bitmap format
#
# from Oskar Schirmer <[e-mail]> Feb 2, 2001
# p M 8 5/6 xx yy zz data...
# Atari ST STAD bitmap is always 640x400, bytewise runlength compressed.
# bytes either run horizontally (pM85) or vertically (pM86). yy is the
# most frequent byte, xx and zz are runlength escape codes, where xx is
# used for runs of yy.
#
0	string	pM85		Atari ST STAD bitmap image data (hor)
>5	byte	0x00		(white background)
>5	byte	0xFF		(black background)
0	string	pM86		Atari ST STAD bitmap image data (vert)
>5	byte	0x00		(white background)
>5	byte	0xFF		(black background)