From gamma!ulysses!andante!princeton!njin!rutgers!iuvax!bsu-cs!ibmbin Wed Dec 31 19:00:00 1969
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From: spcecdt@ucscb.UCSC.EDU (John DuBois)
Newsgroups: comp.binaries.ibm.pc
Subject: "compress" for MS-DOS, executable
Message-ID: <4288@bsu-cs.UUCP>
Date: Wed, 12-Oct-88 08:07:59 EDT
Article-I.D.: bsu-cs.4288
Posted: Wed Oct 12 08:07:59 1988
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Summary: compexe.arc, "compress" for MS-DOS, executable


This is the source and executable versions of "compress", modified to
compile with Turbo C.  The version I got was modified to compile with
MSC; I've changed some stuff so that it will compile under Turbo C and
I fixed some problems that with the DOS version.

It is useful in transfering files with Unix systems, since text files
are often compressed by about 50%, thus halving transmission time.
Also, it is a nice compression utility for single files since you don't
have to do an archive listing to see what is in the file.  Unlike
archiving utilities it automatically removes the (un)compressed version
when you compress/uncompress.  Finally, if the program is named
zcat.exe it will behave the same way "compress" does on Unix systems
when invoked under that name; this can be very useful.

Unfortunately piping stuff into "compress" on DOS does not seem to work
well, and you can't pipe into "uncompress" because DOS is braindead
about piping binary files; it stops writing to the temporary file when
it encounters ^Z.

I could only get it to compile in the small model (12-bit version)
under Turbo C.  This means that it can only uncompress files that were
compressed using 12 bit codes, so if a file is to be compressed on some
other system and uncompressed on DOS it should be compressed with the
-b12 flag.  The 12 bit version has the advantage that it will work with
much less free memory and is faster, though the compression is not
quite as good.

Remember to use the -i (image) flag when compressing and uncompressing
binary files under DOS.

If anyone fixes the piping-to-compress problem or gets a >12bit version
to compile, please let me know.

	John DuBois
	spcecdt@ucscb.ucsc.edu
	...!ucbvax!ucscc!ucscb!spcecdt 
-----------------------------------------------------------------------

			ADDITIONAL NOTES

1.  Mr. DuBois is correct that a >12 bit version will not compile
    under TurboC 1.5.  The reason is that the program exceeds the
    compiler's limitation on global variables.  MSC 4.0/5, on the
    other hand, can handle it.  Therefore, the program was re-ported
    back to MSC compatibility.  The 12 bit version will still compile
    under TurboC.

2.  The program has been modified to substitute a '-a' flag for the
    '-i' flag that Mr. DuBois used, with the difference that by
    default LF to CR/LF conversions are DISABLED.  (Thus, the -a
    flag is identical to the -a flag used in the various ZMODEM
    programs.)  The reason is that once a file that must be
    unchanged (e.g., executable file, archive, etc.) is compressed
    with the conversions enabled, it may be impossible to recreate
    the original.  It seemed desirable to make this possibility
    one that must be selected consciously.

3.  The compiled full version (compact model) is a 468K file.  This
    is wasteful, and should be run through exepack.  The savings is
    very substantial:  the exepacked compress.exe is only 27K!  Since
    TurboC does not include a utility comparable to exepack, this is
    another reason for compiling under MSC.

				bellcore!lcuxa!mike2