Convert tabs to spaces in the libjpeg code and the SIMD code (TurboJPEG retains the use of tabs for historical reasons. They were annoying in the libjpeg code primarily because they were not consistently used and because they were used to format as well as indent the code. In the case of TurboJPEG, tabs are used just to indent the code, so even if the editor assumes a different tab width, the code will still be readable.)

git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1278 632fc199-4ca6-4c93-a231-07263d6284db

1 files changed, 212 insertions, 212 deletions

diff --git a/usage.txt b/usage.txt
index 775a544..14ab77b 100644
--- a/usage.txt
+++ b/usage.txt
@@ -26,27 +26,27 @@ We provide two programs, cjpeg to compress an image file into JPEG format,
 and djpeg to decompress a JPEG file back into a conventional image format.
 
 On Unix-like systems, you say:
-	cjpeg [switches] [imagefile] >jpegfile
+        cjpeg [switches] [imagefile] >jpegfile
 or
-	djpeg [switches] [jpegfile]  >imagefile
+        djpeg [switches] [jpegfile]  >imagefile
 The programs read the specified input file, or standard input if none is
 named.  They always write to standard output (with trace/error messages to
 standard error).  These conventions are handy for piping images between
 programs.
 
 On most non-Unix systems, you say:
-	cjpeg [switches] imagefile jpegfile
+        cjpeg [switches] imagefile jpegfile
 or
-	djpeg [switches] jpegfile  imagefile
+        djpeg [switches] jpegfile  imagefile
 i.e., both the input and output files are named on the command line.  This
 style is a little more foolproof, and it loses no functionality if you don't
 have pipes.  (You can get this style on Unix too, if you prefer, by defining
 TWO_FILE_COMMANDLINE when you compile the programs; see install.txt.)
 
 You can also say:
-	cjpeg [switches] -outfile jpegfile  imagefile
+        cjpeg [switches] -outfile jpegfile  imagefile
 or
-	djpeg [switches] -outfile imagefile  jpegfile
+        djpeg [switches] -outfile imagefile  jpegfile
 This syntax works on all systems, so it is useful for scripts.
 
 The currently supported image file formats are: PPM (PBMPLUS color format),
@@ -69,35 +69,35 @@ CJPEG DETAILS
 
 The basic command line switches for cjpeg are:
 
-	-quality N[,...]  Scale quantization tables to adjust image quality.
-			Quality is 0 (worst) to 100 (best); default is 75.
-			(See below for more info.)
+        -quality N[,...]  Scale quantization tables to adjust image quality.
+                          Quality is 0 (worst) to 100 (best); default is 75.
+                          (See below for more info.)
 
-	-grayscale	Create monochrome JPEG file from color input.
-			Be sure to use this switch when compressing a grayscale
-			BMP file, because cjpeg isn't bright enough to notice
-			whether a BMP file uses only shades of gray.  By
-			saying -grayscale, you'll get a smaller JPEG file that
-			takes less time to process.
+        -grayscale      Create monochrome JPEG file from color input.
+                        Be sure to use this switch when compressing a grayscale
+                        BMP file, because cjpeg isn't bright enough to notice
+                        whether a BMP file uses only shades of gray.  By
+                        saying -grayscale, you'll get a smaller JPEG file that
+                        takes less time to process.
 
-	-rgb		Create RGB JPEG file.
-			Using this switch suppresses the conversion from RGB
-			colorspace input to the default YCbCr JPEG colorspace.
+        -rgb            Create RGB JPEG file.
+                        Using this switch suppresses the conversion from RGB
+                        colorspace input to the default YCbCr JPEG colorspace.
 
-	-optimize	Perform optimization of entropy encoding parameters.
-			Without this, default encoding parameters are used.
-			-optimize usually makes the JPEG file a little smaller,
-			but cjpeg runs somewhat slower and needs much more
-			memory.  Image quality and speed of decompression are
-			unaffected by -optimize.
+        -optimize       Perform optimization of entropy encoding parameters.
+                        Without this, default encoding parameters are used.
+                        -optimize usually makes the JPEG file a little smaller,
+                        but cjpeg runs somewhat slower and needs much more
+                        memory.  Image quality and speed of decompression are
+                        unaffected by -optimize.
 
-	-progressive	Create progressive JPEG file (see below).
+        -progressive    Create progressive JPEG file (see below).
 
-	-targa		Input file is Targa format.  Targa files that contain
-			an "identification" field will not be automatically
-			recognized by cjpeg; for such files you must specify
-			-targa to make cjpeg treat the input as Targa format.
-			For most Targa files, you won't need this switch.
+        -targa          Input file is Targa format.  Targa files that contain
+                        an "identification" field will not be automatically
+                        recognized by cjpeg; for such files you must specify
+                        -targa to make cjpeg treat the input as Targa format.
+                        For most Targa files, you won't need this switch.
 
 The -quality switch lets you trade off compressed file size against quality of
 the reconstructed image: the higher the quality setting, the larger the JPEG
@@ -164,38 +164,38 @@ file size is about the same --- often a little smaller.
 
 Switches for advanced users:
 
-	-arithmetic	Use arithmetic coding.  CAUTION: arithmetic coded JPEG
-			is not yet widely implemented, so many decoders will
-			be unable to view an arithmetic coded JPEG file at
-			all.
-
-	-dct int	Use integer DCT method (default).
-	-dct fast	Use fast integer DCT (less accurate).
-	-dct float	Use floating-point DCT method.
-			The float method is very slightly more accurate than
-			the int method, but is much slower unless your machine
-			has very fast floating-point hardware.  Also note that
-			results of the floating-point method may vary slightly
-			across machines, while the integer methods should give
-			the same results everywhere.  The fast integer method
-			is much less accurate than the other two.
-
-	-restart N	Emit a JPEG restart marker every N MCU rows, or every
-			N MCU blocks if "B" is attached to the number.
-			-restart 0 (the default) means no restart markers.
-
-	-smooth N	Smooth the input image to eliminate dithering noise.
-			N, ranging from 1 to 100, indicates the strength of
-			smoothing.  0 (the default) means no smoothing.
-
-	-maxmemory N	Set limit for amount of memory to use in processing
-			large images.  Value is in thousands of bytes, or
-			millions of bytes if "M" is attached to the number.
-			For example, -max 4m selects 4000000 bytes.  If more
-			space is needed, temporary files will be used.
-
-	-verbose	Enable debug printout.  More -v's give more printout.
-	or  -debug	Also, version information is printed at startup.
+        -arithmetic     Use arithmetic coding.  CAUTION: arithmetic coded JPEG
+                        is not yet widely implemented, so many decoders will
+                        be unable to view an arithmetic coded JPEG file at
+                        all.
+
+        -dct int        Use integer DCT method (default).
+        -dct fast       Use fast integer DCT (less accurate).
+        -dct float      Use floating-point DCT method.
+                        The float method is very slightly more accurate than
+                        the int method, but is much slower unless your machine
+                        has very fast floating-point hardware.  Also note that
+                        results of the floating-point method may vary slightly
+                        across machines, while the integer methods should give
+                        the same results everywhere.  The fast integer method
+                        is much less accurate than the other two.
+
+        -restart N      Emit a JPEG restart marker every N MCU rows, or every
+                        N MCU blocks if "B" is attached to the number.
+                        -restart 0 (the default) means no restart markers.
+
+        -smooth N       Smooth the input image to eliminate dithering noise.
+                        N, ranging from 1 to 100, indicates the strength of
+                        smoothing.  0 (the default) means no smoothing.
+
+        -maxmemory N    Set limit for amount of memory to use in processing
+                        large images.  Value is in thousands of bytes, or
+                        millions of bytes if "M" is attached to the number.
+                        For example, -max 4m selects 4000000 bytes.  If more
+                        space is needed, temporary files will be used.
+
+        -verbose        Enable debug printout.  More -v's give more printout.
+        or  -debug      Also, version information is printed at startup.
 
 The -restart option inserts extra markers that allow a JPEG decoder to
 resynchronize after a transmission error.  Without restart markers, any damage
@@ -213,22 +213,22 @@ factor will visibly blur the image, however.
 
 Switches for wizards:
 
-	-baseline	Force baseline-compatible quantization tables to be
-			generated.  This clamps quantization values to 8 bits
-			even at low quality settings.  (This switch is poorly
-			named, since it does not ensure that the output is
-			actually baseline JPEG.  For example, you can use
-			-baseline and -progressive together.)
+        -baseline       Force baseline-compatible quantization tables to be
+                        generated.  This clamps quantization values to 8 bits
+                        even at low quality settings.  (This switch is poorly
+                        named, since it does not ensure that the output is
+                        actually baseline JPEG.  For example, you can use
+                        -baseline and -progressive together.)
 
-	-qtables file	Use the quantization tables given in the specified
-			text file.
+        -qtables file   Use the quantization tables given in the specified
+                        text file.
 
-	-qslots N[,...] Select which quantization table to use for each color
-			component.
+        -qslots N[,...] Select which quantization table to use for each color
+                        component.
 
-	-sample HxV[,...]  Set JPEG sampling factors for each color component.
+        -sample HxV[,...]  Set JPEG sampling factors for each color component.
 
-	-scans file	Use the scan script given in the specified text file.
+        -scans file     Use the scan script given in the specified text file.
 
 The "wizard" switches are intended for experimentation with JPEG.  If you
 don't know what you are doing, DON'T USE THEM.  These switches are documented
@@ -239,106 +239,106 @@ DJPEG DETAILS
 
 The basic command line switches for djpeg are:
 
-	-colors N	Reduce image to at most N colors.  This reduces the
-	or -quantize N	number of colors used in the output image, so that it
-			can be displayed on a colormapped display or stored in
-			a colormapped file format.  For example, if you have
-			an 8-bit display, you'd need to reduce to 256 or fewer
-			colors.  (-colors is the recommended name, -quantize
-			is provided only for backwards compatibility.)
-
-	-fast		Select recommended processing options for fast, low
-			quality output.  (The default options are chosen for
-			highest quality output.)  Currently, this is equivalent
-			to "-dct fast -nosmooth -onepass -dither ordered".
-
-	-grayscale	Force gray-scale output even if JPEG file is color.
-			Useful for viewing on monochrome displays; also,
-			djpeg runs noticeably faster in this mode.
-
-	-scale M/N	Scale the output image by a factor M/N.  Currently
-			the scale factor must be M/8, where M is an integer
-			between 1 and 16 inclusive, or any reduced fraction
-			thereof (such as 1/2, 3/4, etc.  Scaling is handy if
-			the image is larger than your screen; also, djpeg runs
-			much faster when scaling down the output.
-
-	-bmp		Select BMP output format (Windows flavor).  8-bit
-			colormapped format is emitted if -colors or -grayscale
-			is specified, or if the JPEG file is gray-scale;
-			otherwise, 24-bit full-color format is emitted.
-
-	-gif		Select GIF output format.  Since GIF does not support
-			more than 256 colors, -colors 256 is assumed (unless
-			you specify a smaller number of colors).  If you
-			specify -fast, the default number of colors is 216.
-
-	-os2		Select BMP output format (OS/2 1.x flavor).  8-bit
-			colormapped format is emitted if -colors or -grayscale
-			is specified, or if the JPEG file is gray-scale;
-			otherwise, 24-bit full-color format is emitted.
-
-	-pnm		Select PBMPLUS (PPM/PGM) output format (this is the
-			default format).  PGM is emitted if the JPEG file is
-			gray-scale or if -grayscale is specified; otherwise
-			PPM is emitted.
-
-	-rle		Select RLE output format.  (Requires URT library.)
-
-	-targa		Select Targa output format.  Gray-scale format is
-			emitted if the JPEG file is gray-scale or if
-			-grayscale is specified; otherwise, colormapped format
-			is emitted if -colors is specified; otherwise, 24-bit
-			full-color format is emitted.
+        -colors N       Reduce image to at most N colors.  This reduces the
+        or -quantize N  number of colors used in the output image, so that it
+                        can be displayed on a colormapped display or stored in
+                        a colormapped file format.  For example, if you have
+                        an 8-bit display, you'd need to reduce to 256 or fewer
+                        colors.  (-colors is the recommended name, -quantize
+                        is provided only for backwards compatibility.)
+
+        -fast           Select recommended processing options for fast, low
+                        quality output.  (The default options are chosen for
+                        highest quality output.)  Currently, this is equivalent
+                        to "-dct fast -nosmooth -onepass -dither ordered".
+
+        -grayscale      Force gray-scale output even if JPEG file is color.
+                        Useful for viewing on monochrome displays; also,
+                        djpeg runs noticeably faster in this mode.
+
+        -scale M/N      Scale the output image by a factor M/N.  Currently
+                        the scale factor must be M/8, where M is an integer
+                        between 1 and 16 inclusive, or any reduced fraction
+                        thereof (such as 1/2, 3/4, etc.  Scaling is handy if
+                        the image is larger than your screen; also, djpeg runs
+                        much faster when scaling down the output.
+
+        -bmp            Select BMP output format (Windows flavor).  8-bit
+                        colormapped format is emitted if -colors or -grayscale
+                        is specified, or if the JPEG file is gray-scale;
+                        otherwise, 24-bit full-color format is emitted.
+
+        -gif            Select GIF output format.  Since GIF does not support
+                        more than 256 colors, -colors 256 is assumed (unless
+                        you specify a smaller number of colors).  If you
+                        specify -fast, the default number of colors is 216.
+
+        -os2            Select BMP output format (OS/2 1.x flavor).  8-bit
+                        colormapped format is emitted if -colors or -grayscale
+                        is specified, or if the JPEG file is gray-scale;
+                        otherwise, 24-bit full-color format is emitted.
+
+        -pnm            Select PBMPLUS (PPM/PGM) output format (this is the
+                        default format).  PGM is emitted if the JPEG file is
+                        gray-scale or if -grayscale is specified; otherwise
+                        PPM is emitted.
+
+        -rle            Select RLE output format.  (Requires URT library.)
+
+        -targa          Select Targa output format.  Gray-scale format is
+                        emitted if the JPEG file is gray-scale or if
+                        -grayscale is specified; otherwise, colormapped format
+                        is emitted if -colors is specified; otherwise, 24-bit
+                        full-color format is emitted.
 
 Switches for advanced users:
 
-	-dct int	Use integer DCT method (default).
-	-dct fast	Use fast integer DCT (less accurate).
-	-dct float	Use floating-point DCT method.
-			The float method is very slightly more accurate than
-			the int method, but is much slower unless your machine
-			has very fast floating-point hardware.  Also note that
-			results of the floating-point method may vary slightly
-			across machines, while the integer methods should give
-			the same results everywhere.  The fast integer method
-			is much less accurate than the other two.
-
-	-dither fs	Use Floyd-Steinberg dithering in color quantization.
-	-dither ordered	Use ordered dithering in color quantization.
-	-dither none	Do not use dithering in color quantization.
-			By default, Floyd-Steinberg dithering is applied when
-			quantizing colors; this is slow but usually produces
-			the best results.  Ordered dither is a compromise
-			between speed and quality; no dithering is fast but
-			usually looks awful.  Note that these switches have
-			no effect unless color quantization is being done.
-			Ordered dither is only available in -onepass mode.
-
-	-map FILE	Quantize to the colors used in the specified image
-			file.  This is useful for producing multiple files
-			with identical color maps, or for forcing a predefined
-			set of colors to be used.  The FILE must be a GIF
-			or PPM file.  This option overrides -colors and
-			-onepass.
-
-	-nosmooth	Use a faster, lower-quality upsampling routine.
-
-	-onepass	Use one-pass instead of two-pass color quantization.
-			The one-pass method is faster and needs less memory,
-			but it produces a lower-quality image.  -onepass is
-			ignored unless you also say -colors N.  Also,
-			the one-pass method is always used for gray-scale
-			output (the two-pass method is no improvement then).
-
-	-maxmemory N	Set limit for amount of memory to use in processing
-			large images.  Value is in thousands of bytes, or
-			millions of bytes if "M" is attached to the number.
-			For example, -max 4m selects 4000000 bytes.  If more
-			space is needed, temporary files will be used.
-
-	-verbose	Enable debug printout.  More -v's give more printout.
-	or  -debug	Also, version information is printed at startup.
+        -dct int        Use integer DCT method (default).
+        -dct fast       Use fast integer DCT (less accurate).
+        -dct float      Use floating-point DCT method.
+                        The float method is very slightly more accurate than
+                        the int method, but is much slower unless your machine
+                        has very fast floating-point hardware.  Also note that
+                        results of the floating-point method may vary slightly
+                        across machines, while the integer methods should give
+                        the same results everywhere.  The fast integer method
+                        is much less accurate than the other two.
+
+        -dither fs      Use Floyd-Steinberg dithering in color quantization.
+        -dither ordered Use ordered dithering in color quantization.
+        -dither none    Do not use dithering in color quantization.
+                        By default, Floyd-Steinberg dithering is applied when
+                        quantizing colors; this is slow but usually produces
+                        the best results.  Ordered dither is a compromise
+                        between speed and quality; no dithering is fast but
+                        usually looks awful.  Note that these switches have
+                        no effect unless color quantization is being done.
+                        Ordered dither is only available in -onepass mode.
+
+        -map FILE       Quantize to the colors used in the specified image
+                        file.  This is useful for producing multiple files
+                        with identical color maps, or for forcing a predefined
+                        set of colors to be used.  The FILE must be a GIF
+                        or PPM file.  This option overrides -colors and
+                        -onepass.
+
+        -nosmooth       Use a faster, lower-quality upsampling routine.
+
+        -onepass        Use one-pass instead of two-pass color quantization.
+                        The one-pass method is faster and needs less memory,
+                        but it produces a lower-quality image.  -onepass is
+                        ignored unless you also say -colors N.  Also,
+                        the one-pass method is always used for gray-scale
+                        output (the two-pass method is no improvement then).
+
+        -maxmemory N    Set limit for amount of memory to use in processing
+                        large images.  Value is in thousands of bytes, or
+                        millions of bytes if "M" is attached to the number.
+                        For example, -max 4m selects 4000000 bytes.  If more
+                        space is needed, temporary files will be used.
+
+        -verbose        Enable debug printout.  More -v's give more printout.
+        or  -debug      Also, version information is printed at startup.
 
 
 HINTS FOR CJPEG
@@ -446,31 +446,31 @@ quality.
 
 jpegtran uses a command line syntax similar to cjpeg or djpeg.
 On Unix-like systems, you say:
-	jpegtran [switches] [inputfile] >outputfile
+        jpegtran [switches] [inputfile] >outputfile
 On most non-Unix systems, you say:
-	jpegtran [switches] inputfile outputfile
+        jpegtran [switches] inputfile outputfile
 where both the input and output files are JPEG files.
 
 To specify the coded JPEG representation used in the output file,
 jpegtran accepts a subset of the switches recognized by cjpeg:
-	-optimize	Perform optimization of entropy encoding parameters.
-	-progressive	Create progressive JPEG file.
-	-arithmetic	Use arithmetic coding.
-	-restart N	Emit a JPEG restart marker every N MCU rows, or every
-			N MCU blocks if "B" is attached to the number.
-	-scans file	Use the scan script given in the specified text file.
+        -optimize       Perform optimization of entropy encoding parameters.
+        -progressive    Create progressive JPEG file.
+        -arithmetic     Use arithmetic coding.
+        -restart N      Emit a JPEG restart marker every N MCU rows, or every
+                        N MCU blocks if "B" is attached to the number.
+        -scans file     Use the scan script given in the specified text file.
 See the previous discussion of cjpeg for more details about these switches.
 If you specify none of these switches, you get a plain baseline-JPEG output
 file.  The quality setting and so forth are determined by the input file.
 
 The image can be losslessly transformed by giving one of these switches:
-	-flip horizontal	Mirror image horizontally (left-right).
-	-flip vertical		Mirror image vertically (top-bottom).
-	-rotate 90		Rotate image 90 degrees clockwise.
-	-rotate 180		Rotate image 180 degrees.
-	-rotate 270		Rotate image 270 degrees clockwise (or 90 ccw).
-	-transpose		Transpose image (across UL-to-LR axis).
-	-transverse		Transverse transpose (across UR-to-LL axis).
+        -flip horizontal        Mirror image horizontally (left-right).
+        -flip vertical          Mirror image vertically (top-bottom).
+        -rotate 90              Rotate image 90 degrees clockwise.
+        -rotate 180             Rotate image 180 degrees.
+        -rotate 270             Rotate image 270 degrees clockwise (or 90 ccw).
+        -transpose              Transpose image (across UL-to-LR axis).
+        -transverse             Transverse transpose (across UR-to-LL axis).
 
 The transpose transformation has no restrictions regarding image dimensions.
 The other transformations operate rather oddly if the image dimensions are not
@@ -491,7 +491,7 @@ transpose-and-flip sequence.
 For practical use, you may prefer to discard any untransformable edge pixels
 rather than having a strange-looking strip along the right and/or bottom edges
 of a transformed image.  To do this, add the -trim switch:
-	-trim		Drop non-transformable edge blocks.
+        -trim           Drop non-transformable edge blocks.
 Obviously, a transformation with -trim is not reversible, so strictly speaking
 jpegtran with this switch is not lossless.  Also, the expected mathematical
 equivalences between the transformations no longer hold.  For example,
@@ -499,8 +499,8 @@ equivalences between the transformations no longer hold.  For example,
 "-rot 180 -trim" trims both edges.
 
 If you are only interested in perfect transformations, add the -perfect switch:
-	-perfect	Fail with an error if the transformation is not
-			perfect.
+        -perfect        Fail with an error if the transformation is not
+                        perfect.
 For example, you may want to do
   jpegtran -rot 90 -perfect foo.jpg || djpeg foo.jpg | pnmflip -r90 | cjpeg
 to do a perfect rotation, if available, or an approximated one if not.
@@ -513,12 +513,12 @@ boundary.  If it doesn't, then it is silently moved up and/or left to the
 nearest iMCU boundary (the lower right corner is unchanged.)
 
 The image can be losslessly cropped by giving the switch:
-	-crop WxH+X+Y	Crop to a rectangular region of width W and height H,
-			starting at point X,Y.
+        -crop WxH+X+Y   Crop to a rectangular region of width W and height H,
+                        starting at point X,Y.
 
 Other not-strictly-lossless transformation switches are:
 
-	-grayscale	Force grayscale output.
+        -grayscale      Force grayscale output.
 This option discards the chrominance channels if the input image is YCbCr
 (ie, a standard color JPEG), resulting in a grayscale JPEG file.  The
 luminance channel is preserved exactly, so this is a better method of reducing
@@ -530,24 +530,24 @@ a grayscale JPEG is substantially less than that for a color JPEG.)
 
 jpegtran also recognizes these switches that control what to do with "extra"
 markers, such as comment blocks:
-	-copy none	Copy no extra markers from source file.  This setting
-			suppresses all comments and other excess baggage
-			present in the source file.
-	-copy comments	Copy only comment markers.  This setting copies
-			comments from the source file but discards
-			any other data that is inessential for image display.
-	-copy all	Copy all extra markers.  This setting preserves
-			miscellaneous markers found in the source file, such
-			as JFIF thumbnails, Exif data, and Photoshop settings.
-			In some files, these extra markers can be sizable.
+        -copy none      Copy no extra markers from source file.  This setting
+                        suppresses all comments and other excess baggage
+                        present in the source file.
+        -copy comments  Copy only comment markers.  This setting copies
+                        comments from the source file but discards
+                        any other data that is inessential for image display.
+        -copy all       Copy all extra markers.  This setting preserves
+                        miscellaneous markers found in the source file, such
+                        as JFIF thumbnails, Exif data, and Photoshop settings.
+                        In some files, these extra markers can be sizable.
 The default behavior is -copy comments.  (Note: in IJG releases v6 and v6a,
 jpegtran always did the equivalent of -copy none.)
 
 Additional switches recognized by jpegtran are:
-	-outfile filename
-	-maxmemory N
-	-verbose
-	-debug
+        -outfile filename
+        -maxmemory N
+        -verbose
+        -debug
 These work the same as in cjpeg or djpeg.
 
 
@@ -566,7 +566,7 @@ blocks to a JPEG file.
 
 rdjpgcom searches a JPEG file and prints the contents of any COM blocks on
 standard output.  The command line syntax is
-	rdjpgcom [-raw] [-verbose] [inputfilename]
+        rdjpgcom [-raw] [-verbose] [inputfilename]
 The switch "-raw" (or just "-r") causes rdjpgcom to output non-printable
 characters in JPEG comments.  These characters are normally escaped for
 security reasons.
@@ -584,18 +584,18 @@ just destroy your file.
 
 The command line syntax for wrjpgcom is similar to cjpeg's.  On Unix-like
 systems, it is
-	wrjpgcom [switches] [inputfilename]
+        wrjpgcom [switches] [inputfilename]
 The output file is written to standard output.  The input file comes from
 the named file, or from standard input if no input file is named.
 
 On most non-Unix systems, the syntax is
-	wrjpgcom [switches] inputfilename outputfilename
+        wrjpgcom [switches] inputfilename outputfilename
 where both input and output file names must be given explicitly.
 
 wrjpgcom understands three switches:
-	-replace		 Delete any existing COM blocks from the file.
-	-comment "Comment text"	 Supply new COM text on command line.
-	-cfile name		 Read text for new COM block from named file.
+        -replace                 Delete any existing COM blocks from the file.
+        -comment "Comment text"  Supply new COM text on command line.
+        -cfile name              Read text for new COM block from named file.
 (Switch names can be abbreviated.)  If you have only one line of comment text
 to add, you can provide it on the command line with -comment.  The comment
 text must be surrounded with quotes so that it is treated as a single