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+IJG JPEG LIBRARY:  ALTERNATE USER INTERFACE FOR CJPEG/DJPEG
+
+Copyright (C) 2020, Guido Vollbeding.
+This file is part of the Independent JPEG Group's software.
+For conditions of distribution and use, see the accompanying README file.
+
+
+There is an alternate command-line user interface for the IJG JPEG software.
+It is designed for use under MS-DOS, and may also be useful on other non-Unix
+operating systems.  (For that matter, this code works fine on Unix, but the
+standard command-line syntax is better on Unix because it is pipe-friendly.)
+
+With this user interface, cjpeg and djpeg accept multiple input file names
+on the command line; output file names are generated by substituting
+appropriate extensions.  The user is prompted before any already-existing
+file will be overwritten.
+
+Expansion of wild-card file specifications is useful but is not directly
+provided by this code.  Most DOS C compilers have the ability to do wild-card
+expansion "behind the scenes", and we rely on that feature.  On other systems,
+the shell may do it for you, as is done on Unix.
+
+Also, a DOS-specific routine is provided to determine available memory;
+this makes the -maxmemory switch unnecessary except in unusual cases.
+If you know how to determine available memory on a different system,
+you can easily add the necessary code.  (And please send it along to
+jpeg-info@jpegclub.org so we can include it in future releases!)
+
+
+INSTALLATION
+============
+
+Rename the standard cjpeg.c file to cjpegstd.c, then rename cjpegalt.c to
+cjpeg.c.
+Rename the standard djpeg.c file to djpegstd.c, then rename djpegalt.c to
+djpeg.c.
+Then build the software as described in install.txt, with these exceptions:
+
+* Define PROGRESS_REPORT in jconfig.h if you want the percent-done display.
+* Define NO_OVERWRITE_CHECK if you *don't* want overwrite confirmation.
+* You may ignore the USE_SETMODE and TWO_FILE_COMMANDLINE symbols discussed
+  in install.txt; these files do not use them.
+* As given, djpegalt.c defaults to BMP output (not PPM output as in the
+  standard djpeg.c).  If you want something different, modify DEFAULT_FMT.
+
+You may also need to do something special to enable filename wild-card
+expansion, assuming your compiler has that capability at all.
+
+Modify the standard usage.txt file as described below.  (If you want to use
+the Unix-style manual pages cjpeg.1 and djpeg.1, better fix them too.)
+
+To restore the standard user interface:
+Rename cjpeg.c to cjpegalt.c, then rename cjpegstd.c to cjpeg.c.
+Rename djpeg.c to djpegalt.c, then rename djpegstd.c to djpeg.c.
+Then recompile/rebuild.
+
+
+Here are some specific notes for popular MS-DOS compilers:
+
+Borland C:
+  Add "-DMSDOS" to CFLAGS to enable use of the DOS memory determination code.
+  Link with the standard library file WILDARGS.OBJ to get wild-card expansion.
+
+Microsoft C:
+  Add "-DMSDOS" to CFLAGS to enable use of the DOS memory determination code.
+  Link with the standard library file SETARGV.OBJ to get wild-card expansion.
+  In the versions I've used, you must also add /NOE to the linker switches to
+  avoid a duplicate-symbol error from including SETARGV.
+
+DJGPP (we recommend version 2.0 or later):
+  Add "-DFREE_MEM_ESTIMATE=0" to CFLAGS.  Wild-card expansion is automatic.
+
+
+USAGE
+=====
+
+Most of the standard usage.txt file also applies to the alternate version,
+but replace its "GENERAL USAGE" section with the text below.  Edit the text
+as necessary if you don't support wildcards or overwrite checking.  Be sure
+to fix the djpeg switch descriptions if you are not defaulting to PPM output.
+Also, if you've provided an accurate memory-estimation procedure, you can
+probably eliminate the HINTS related to the -maxmemory switch.
+
+
+GENERAL USAGE
+
+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.
+
+The basic command line is:
+	cjpeg [switches] list of image files
+or
+	djpeg [switches] list of jpeg files
+
+Each file named is compressed or decompressed.  The input file(s) are not
+modified; the output data is written to files which have the same names
+except for extension.  cjpeg always uses ".jpg" for the output file name's
+extension; djpeg uses one of ".bmp", ".gif", ".ppm", ".rle", or ".tga",
+depending on what output format is selected by the switches.
+
+For example, to convert xxx.bmp to xxx.jpg and yyy.ppm to yyy.jpg, say:
+	cjpeg xxx.bmp yyy.ppm
+
+On most systems you can use standard wildcards to specify the list of input
+files; for example, on DOS "djpeg *.jpg" decompresses all the JPEG files in
+the current directory.
+
+If an intended output file already exists, you'll be asked whether or not to
+overwrite it.  If you say no, the program skips that input file and goes on
+to the next one.
+
+You can intermix switches and file names; for example
+	djpeg -gif file1.jpg -targa file2.jpg
+decompresses file1.jpg into GIF format (file1.gif) and file2.jpg into Targa
+format (file2.tga).  Only switches to the left of a given file name affect
+processing of that file; when there are conflicting switches, the rightmost
+one takes precedence.
+
+You can override the program's choice of output file name by using the
+-outfile switch, as in
+	cjpeg -outfile output.jpg input.ppm
+-outfile only affects the first input file name to its right.
+
+The currently supported image file formats are: PPM (PBMPLUS color format),
+PGM (PBMPLUS grayscale format), BMP, GIF, Targa, and RLE (Utah Raster Toolkit
+format).  (RLE is supported only if the URT library is available, which it
+isn't on most non-Unix systems.)  cjpeg recognizes the input image format
+automatically, with the exception of some Targa-format files.  You have to
+tell djpeg which format to generate.
+
+JPEG files are in the standard JFIF file format.  There are other,
+less widely used JPEG-based file formats, but we don't support them.
+
+All switch names may be abbreviated; for example, -grayscale may be written
+-gray or -gr.  Most of the "basic" switches can be abbreviated to as little as
+one letter.  Upper and lower case are equivalent (-BMP is the same as -bmp).
+British spellings are also accepted (e.g., -greyscale), though for brevity
+these are not mentioned below.