
# This is a shell archive.  Remove anything before this line,
# then unpack it by saving it in a file and typing "sh file".
#
# Wrapped by Edwin Kremer <edwin@zlotty> on Wed Dec 20 17:08:59 1989
#
# This archive contains:
#	Makefile	README		USERMEM		compress.c	
#	usermem.sh	
#

LANG=""; export LANG
PATH=/bin:/usr/bin:$PATH; export PATH

echo x - Makefile
cat >Makefile <<'@EOF'
#
#	@(#)Makefile	5.5 (Berkeley) 9/18/85
#
COMFLAGS=-DBSD4_2 -O -DSACREDMEM=256000
BIN=${DESTDIR}/usr/ucb

compress: compress.c USERMEM
	cc $(COMFLAGS) -DUSERMEM=`cat USERMEM` -o compress compress.c

# USERMEM may have to be set by hand.  It should contain the amount of
# available user memory in bytes.  Set it to zero, for physical memory
# less than 1 Meg.
USERMEM:
	sh usermem.sh > USERMEM

install: compress
	install -s compress $(BIN)
	rm -f $(BIN)/uncompress $(BIN)/zcat
	ln $(BIN)/compress $(BIN)/uncompress
	ln $(BIN)/compress $(BIN)/zcat

# Temporarily don't delete USERMEM.  When chroot'ed to /nbsd, usermem.sh
# fails totally.
clean:
	rm -f compress core errs
#	rm -f compress USERMEM core errs
@EOF

chmod 440 Makefile

echo x - README
sed 's/^@//' >README <<'@EOF'

	@(#)README	5.3 (Berkeley) 9/17/85

Compress version 4.0 improvements over 3.0:
	o compress() speedup (10-50%) by changing division hash to xor
	o decompress() speedup (5-10%)
	o Memory requirements reduced (3-30%)
	o Stack requirements reduced to less than 4kb
	o Removed 'Big+Fast' compress code (FBITS) because of compress speedup
    	o Portability mods for Z8000 and PC/XT (but not zeus 3.2)
	o Default to 'quiet' mode
	o Unification of 'force' flags
	o Manual page overhaul
	o Portability enhancement for M_XENIX
	o Removed text on #else and #endif
	o Added "-V" switch to print version and options
	o Added #defines for SIGNED_COMPARE_SLOW
	o Added Makefile and "usermem" program
	o Removed all floating point computations
	o New programs: [deleted]

The "usermem" script attempts to determine the maximum process size.  Some
editing of the script may be necessary (see the comments).  [It should work
fine on 4.3 bsd.] If you can't get it to work at all, just create file
"USERMEM" containing the maximum process size in decimal.

The following preprocessor symbols control the compilation of "compress.c":

	o USERMEM		Maximum process memory on the system
	o SACREDMEM		Amount to reserve for other proceses
	o SIGNED_COMPARE_SLOW	Unsigned compare instructions are faster
	o NO_UCHAR		Don't use "unsigned char" types
	o BITS			Overrules default set by USERMEM-SACREDMEM
	o vax			Generate inline assembler
	o interdata		Defines SIGNED_COMPARE_SLOW
	o M_XENIX		Makes arrays < 65536 bytes each
	o pdp11			BITS=12, NO_UCHAR
	o z8000			BITS=12
	o pcxt			BITS=12
	o BSD4_2		Allow long filenames ( > 14 characters) &
				Call setlinebuf(stderr)

The difference "usermem-sacredmem" determines the maximum BITS that can be
specified with the "-b" flag.

memory: at least		BITS
------  -- -----                ----
     433,484			 16
     229,600			 15
     127,536			 14
      73,464			 13
           0			 12

The default is BITS=16.

The maximum bits can be overrulled by specifying "-DBITS=bits" at
compilation time.

WARNING: files compressed on a large machine with more bits than allowed by 
a version of compress on a smaller machine cannot be decompressed!  Use the
"-b12" flag to generate a file on a large machine that can be uncompressed 
on a 16-bit machine.

The output of compress 4.0 is fully compatible with that of compress 3.0.
In other words, the output of compress 4.0 may be fed into uncompress 3.0 or
the output of compress 3.0 may be fed into uncompress 4.0.

The output of compress 4.0 not compatible with that of
compress 2.0.  However, compress 4.0 still accepts the output of
compress 2.0.  To generate output that is compatible with compress
2.0, use the undocumented "-C" flag.

	-from mod.sources, submitted by vax135!petsd!joe (Joe Orost), 8/1/85
--------------------------------

Enclosed is compress version 3.0 with the following changes:

1.	"Block" compression is performed.  After the BITS run out, the
	compression ratio is checked every so often.  If it is decreasing,
	the table is cleared and a new set of substrings are generated.

	This makes the output of compress 3.0 not compatible with that of
	compress 2.0.  However, compress 3.0 still accepts the output of
	compress 2.0.  To generate output that is compatible with compress
	2.0, use the undocumented "-C" flag.

2.	A quiet "-q" flag has been added for use by the news system.

3.	The character chaining has been deleted and the program now uses
	hashing.  This improves the speed of the program, especially
	during decompression.  Other speed improvements have been made,
	such as using putc() instead of fwrite().

4.	A large table is used on large machines when a relatively small
	number of bits is specified.  This saves much time when compressing
	for a 16-bit machine on a 32-bit virtual machine.  Note that the
	speed improvement only occurs when the input file is > 30000
	characters, and the -b BITS is less than or equal to the cutoff
	described below.

Most of these changes were made by James A. Woods (ames!jaw).  Thank you
James!

To compile compress:

	cc -O -DUSERMEM=usermem -o compress compress.c

Where "usermem" is the amount of physical user memory available (in bytes).  
If any physical memory is to be reserved for other processes, put in 
"-DSACREDMEM sacredmem", where "sacredmem" is the amount to be reserved.

The difference "usermem-sacredmem" determines the maximum BITS that can be
specified, and the cutoff bits where the large+fast table is used.

memory: at least		BITS		cutoff
------  -- -----                ----            ------
   4,718,592 			 16		  13
   2,621,440 			 16		  12
   1,572,864			 16		  11
   1,048,576			 16		  10
     631,808			 16               --
     329,728			 15               --
     178,176			 14		  --
      99,328			 13		  --
           0			 12		  --

The default memory size is 750,000 which gives a maximum BITS=16 and no
large+fast table.

The maximum bits can be overruled by specifying "-DBITS=bits" at
compilation time.

If your machine doesn't support unsigned characters, define "NO_UCHAR" 
when compiling.

If your machine has "int" as 16-bits, define "SHORT_INT" when compiling.

After compilation, move "compress" to a standard executable location, such 
as /usr/local.  Then:
	cd /usr/local
	ln compress uncompress
	ln compress zcat

On machines that have a fixed stack size (such as Perkin-Elmer), set the
stack to at least 12kb.  ("setstack compress 12" on Perkin-Elmer).

Next, install the manual (compress.l).
	cp compress.l /usr/man/manl
	cd /usr/man/manl
	ln compress.l uncompress.l
	ln compress.l zcat.l

		- or -

	cp compress.l /usr/man/man1/compress.1
	cd /usr/man/man1
	ln compress.1 uncompress.1
	ln compress.1 zcat.1

					regards,
					petsd!joe

Here is a note from the net:

>From hplabs!pesnta!amd!turtlevax!ken Sat Jan  5 03:35:20 1985
Path: ames!hplabs!pesnta!amd!turtlevax!ken
@From: ken@turtlevax.UUCP (Ken Turkowski)
Newsgroups: net.sources
Subject: Re: Compress release 3.0 : sample Makefile
Organization: CADLINC, Inc. @ Menlo Park, CA

In the compress 3.0 source recently posted to mod.sources, there is a
#define variable which can be set for optimum performance on a machine
with a large amount of memory.  A program (usermem) to calculate the
useable amount of physical user memory is enclosed, as well as a sample
4.2bsd Vax Makefile for compress.

Here is the README file from the previous version of compress (2.0):

>Enclosed is compress.c version 2.0 with the following bugs fixed:
>
>1.	The packed files produced by compress are different on different
>	machines and dependent on the vax sysgen option.
>		The bug was in the different byte/bit ordering on the
>		various machines.  This has been fixed.
>
>		This version is NOT compatible with the original vax posting
>		unless the '-DCOMPATIBLE' option is specified to the C
>		compiler.  The original posting has a bug which I fixed, 
>		causing incompatible files.  I recommend you NOT to use this
>		option unless you already have a lot of packed files from
>		the original posting by thomas.
>2.	The exit status is not well defined (on some machines) causing the
>	scripts to fail.
>		The exit status is now 0,1 or 2 and is documented in
>		compress.l.
>3.	The function getopt() is not available in all C libraries.
>		The function getopt() is no longer referenced by the
>		program.
>4.	Error status is not being checked on the fwrite() and fflush() calls.
>		Fixed.
>
>The following enhancements have been made:
>
>1.	Added facilities of "compact" into the compress program.  "Pack",
>	"Unpack", and "Pcat" are no longer required (no longer supplied).
>2.	Installed work around for C compiler bug with "-O".
>3.	Added a magic number header (\037\235).  Put the bits specified
>	in the file.
>4.	Added "-f" flag to force overwrite of output file.
>5.	Added "-c" flag and "zcat" program.  'ln compress zcat' after you
>	compile.
>6.	The 'uncompress' script has been deleted; simply 
>	'ln compress uncompress' after you compile and it will work.
>7.	Removed extra bit masking for machines that support unsigned
>	characters.  If your machine doesn't support unsigned characters,
>	define "NO_UCHAR" when compiling.
>
>Compile "compress.c" with "-O -o compress" flags.  Move "compress" to a
>standard executable location, such as /usr/local.  Then:
>	cd /usr/local
>	ln compress uncompress
>	ln compress zcat
>
>On machines that have a fixed stack size (such as Perkin-Elmer), set the
>stack to at least 12kb.  ("setstack compress 12" on Perkin-Elmer).
>
>Next, install the manual (compress.l).
>	cp compress.l /usr/man/manl		- or -
>	cp compress.l /usr/man/man1/compress.1
>
>Here is the README that I sent with my first posting:
>
>>Enclosed is a modified version of compress.c, along with scripts to make it
>>run identically to pack(1), unpack(1), an pcat(1).  Here is what I
>>(petsd!joe) and a colleague (petsd!peora!srd) did:
>>
>>1. Removed VAX dependencies.
>>2. Changed the struct to separate arrays; saves mucho memory.
>>3. Did comparisons in unsigned, where possible.  (Faster on Perkin-Elmer.)
>>4. Sorted the character next chain and changed the search to stop
>>prematurely.  This saves a lot on the execution time when compressing.
>>
>>This version is totally compatible with the original version.  Even though
>>lint(1) -p has no complaints about compress.c, it won't run on a 16-bit
>>machine, due to the size of the arrays.
>>
>>Here is the README file from the original author:
>> 
>>>Well, with all this discussion about file compression (for news batching
>>>in particular) going around, I decided to implement the text compression
>>>algorithm described in the June Computer magazine.  The author claimed
>>>blinding speed and good compression ratios.  It's certainly faster than
>>>compact (but, then, what wouldn't be), but it's also the same speed as
>>>pack, and gets better compression than both of them.  On 350K bytes of
>>>unix-wizards, compact took about 8 minutes of CPU, pack took about 80
>>>seconds, and compress (herein) also took 80 seconds.  But, compact and
>>>pack got about 30% compression, whereas compress got over 50%.  So, I
>>>decided I had something, and that others might be interested, too.
>>>
>>>As is probably true of compact and pack (although I haven't checked),
>>>the byte order within a word is probably relevant here, but as long as
>>>you stay on a single machine type, you should be ok.  (Can anybody
>>>elucidate on this?)  There are a couple of asm's in the code (extv and
>>>insv instructions), so anyone porting it to another machine will have to
>>>deal with this anyway (and could probably make it compatible with Vax
>>>byte order at the same time).  Anyway, I've linted the code (both with
>>>and without -p), so it should run elsewhere.  Note the longs in the
>>>code, you can take these out if you reduce BITS to <= 15.
>>>
>>>Have fun, and as always, if you make good enhancements, or bug fixes,
>>>I'd like to see them.
>>>
>>>=Spencer (thomas@utah-20, {harpo,hplabs,arizona}!utah-cs!thomas)
>>
>>					regards,
>>					joe
>>
>>--
>>Full-Name:  Joseph M. Orost
>>UUCP:       ..!{decvax,ucbvax,ihnp4}!vax135!petsd!joe
>>US Mail:    MS 313; Perkin-Elmer; 106 Apple St; Tinton Falls, NJ 07724
>>Phone:      (201) 870-5844
@EOF

chmod 440 README

echo x - USERMEM
cat >USERMEM <<'@EOF'
1170000
@EOF

chmod 640 USERMEM

echo x - compress.c
cat >compress.c <<'@EOF'
#ifndef lint
static char sccsid[] = "@(#)compress.c	@(#)compress.c	5.9 (Berkeley) 5/11/86";
#endif not lint

/* 
 * Compress - data compression program 
 */
#define	min(a,b)	((a>b) ? b : a)

/*
 * machine variants which require cc -Dmachine:  pdp11, z8000, pcxt
 */

/*
 * Set USERMEM to the maximum amount of physical user memory available
 * in bytes.  USERMEM is used to determine the maximum BITS that can be used
 * for compression.
 *
 * SACREDMEM is the amount of physical memory saved for others; compress
 * will hog the rest.
 */
#ifndef SACREDMEM
#define SACREDMEM	0
#endif

#ifndef USERMEM
# define USERMEM 	450000	/* default user memory */
#endif

#ifdef interdata		/* (Perkin-Elmer) */
#define SIGNED_COMPARE_SLOW	/* signed compare is slower than unsigned */
#endif

#ifdef pdp11
# define BITS 	12	/* max bits/code for 16-bit machine */
# define NO_UCHAR	/* also if "unsigned char" functions as signed char */
# undef USERMEM 
#endif /* pdp11 */	/* don't forget to compile with -i */

#ifdef z8000
# define BITS 	12
# undef vax		/* weird preprocessor */
# undef USERMEM 
#endif /* z8000 */

#ifdef pcxt
# define BITS   12
# undef USERMEM
#endif /* pcxt */

#ifdef USERMEM
# if USERMEM >= (433484+SACREDMEM)
#  define PBITS	16
# else
#  if USERMEM >= (229600+SACREDMEM)
#   define PBITS	15
#  else
#   if USERMEM >= (127536+SACREDMEM)
#    define PBITS	14
#   else
#    if USERMEM >= (73464+SACREDMEM)
#     define PBITS	13
#    else
#     define PBITS	12
#    endif
#   endif
#  endif
# endif
# undef USERMEM
#endif /* USERMEM */

#ifdef PBITS		/* Preferred BITS for this memory size */
# ifndef BITS
#  define BITS PBITS
# endif BITS
#endif /* PBITS */

#if BITS == 16
# define HSIZE	69001		/* 95% occupancy */
#endif
#if BITS == 15
# define HSIZE	35023		/* 94% occupancy */
#endif
#if BITS == 14
# define HSIZE	18013		/* 91% occupancy */
#endif
#if BITS == 13
# define HSIZE	9001		/* 91% occupancy */
#endif
#if BITS <= 12
# define HSIZE	5003		/* 80% occupancy */
#endif

#ifdef M_XENIX			/* Stupid compiler can't handle arrays with */
# if BITS == 16			/* more than 65535 bytes - so we fake it */
#  define XENIX_16
# else
#  if BITS > 13			/* Code only handles BITS = 12, 13, or 16 */
#   define BITS	13
#  endif
# endif
#endif

/*
 * a code_int must be able to hold 2**BITS values of type int, and also -1
 */
#if BITS > 15
typedef long int	code_int;
#else
typedef int		code_int;
#endif

#ifdef SIGNED_COMPARE_SLOW
typedef unsigned long int count_int;
typedef unsigned short int count_short;
#else
typedef long int	  count_int;
#endif

#ifdef NO_UCHAR
 typedef char	char_type;
#else
 typedef	unsigned char	char_type;
#endif /* UCHAR */
char_type magic_header[] = { "\037\235" };	/* 1F 9D */

/* Defines for third byte of header */
#define BIT_MASK	0x1f
#define BLOCK_MASK	0x80
/* Masks 0x40 and 0x20 are free.  I think 0x20 should mean that there is
   a fourth header byte (for expansion).
*/
#define INIT_BITS 9			/* initial number of bits/code */

/*
 * compress.c - File compression ala IEEE Computer, June 1984.
 *
 * Authors:	Spencer W. Thomas	(decvax!utah-cs!thomas)
 *		Jim McKie		(decvax!mcvax!jim)
 *		Steve Davies		(decvax!vax135!petsd!peora!srd)
 *		Ken Turkowski		(decvax!decwrl!turtlevax!ken)
 *		James A. Woods		(decvax!ihnp4!ames!jaw)
 *		Joe Orost		(decvax!vax135!petsd!joe)
 *
 * $Header: compress.c,v 4.0 85/07/30 12:50:00 joe Release $
 * $Log:	compress.c,v $
 * Revision 4.0  85/07/30  12:50:00  joe
 * Removed ferror() calls in output routine on every output except first.
 * Prepared for release to the world.
 * 
 * Revision 3.6  85/07/04  01:22:21  joe
 * Remove much wasted storage by overlaying hash table with the tables
 * used by decompress: tab_suffix[1<<BITS], stack[8000].  Updated USERMEM
 * computations.  Fixed dump_tab() DEBUG routine.
 *
 * Revision 3.5  85/06/30  20:47:21  jaw
 * Change hash function to use exclusive-or.  Rip out hash cache.  These
 * speedups render the megamemory version defunct, for now.  Make decoder
 * stack global.  Parts of the RCS trunks 2.7, 2.6, and 2.1 no longer apply.
 *
 * Revision 3.4  85/06/27  12:00:00  ken
 * Get rid of all floating-point calculations by doing all compression ratio
 * calculations in fixed point.
 *
 * Revision 3.3  85/06/24  21:53:24  joe
 * Incorporate portability suggestion for M_XENIX.  Got rid of text on #else
 * and #endif lines.  Cleaned up #ifdefs for vax and interdata.
 *
 * Revision 3.2  85/06/06  21:53:24  jaw
 * Incorporate portability suggestions for Z8000, IBM PC/XT from mailing list.
 * Default to "quiet" output (no compression statistics).
 *
 * Revision 3.1  85/05/12  18:56:13  jaw
 * Integrate decompress() stack speedups (from early pointer mods by McKie).
 * Repair multi-file USERMEM gaffe.  Unify 'force' flags to mimic semantics
 * of SVR2 'pack'.  Streamline block-compress table clear logic.  Increase 
 * output byte count by magic number size.
 * 
 * Revision 3.0   84/11/27  11:50:00  petsd!joe
 * Set HSIZE depending on BITS.  Set BITS depending on USERMEM.  Unrolled
 * loops in clear routines.  Added "-C" flag for 2.0 compatibility.  Used
 * unsigned compares on Perkin-Elmer.  Fixed foreground check.
 *
 * Revision 2.7   84/11/16  19:35:39  ames!jaw
 * Cache common hash codes based on input statistics; this improves
 * performance for low-density raster images.  Pass on #ifdef bundle
 * from Turkowski.
 *
 * Revision 2.6   84/11/05  19:18:21  ames!jaw
 * Vary size of hash tables to reduce time for small files.
 * Tune PDP-11 hash function.
 *
 * Revision 2.5   84/10/30  20:15:14  ames!jaw
 * Junk chaining; replace with the simpler (and, on the VAX, faster)
 * double hashing, discussed within.  Make block compression standard.
 *
 * Revision 2.4   84/10/16  11:11:11  ames!jaw
 * Introduce adaptive reset for block compression, to boost the rate
 * another several percent.  (See mailing list notes.)
 *
 * Revision 2.3   84/09/22  22:00:00  petsd!joe
 * Implemented "-B" block compress.  Implemented REVERSE sorting of tab_next.
 * Bug fix for last bits.  Changed fwrite to putchar loop everywhere.
 *
 * Revision 2.2   84/09/18  14:12:21  ames!jaw
 * Fold in news changes, small machine typedef from thomas,
 * #ifdef interdata from joe.
 *
 * Revision 2.1   84/09/10  12:34:56  ames!jaw
 * Configured fast table lookup for 32-bit machines.
 * This cuts user time in half for b <= FBITS, and is useful for news batching
 * from VAX to PDP sites.  Also sped up decompress() [fwrite->putc] and
 * added signal catcher [plus beef in writeerr()] to delete effluvia.
 *
 * Revision 2.0   84/08/28  22:00:00  petsd!joe
 * Add check for foreground before prompting user.  Insert maxbits into
 * compressed file.  Force file being uncompressed to end with ".Z".
 * Added "-c" flag and "zcat".  Prepared for release.
 *
 * Revision 1.10  84/08/24  18:28:00  turtlevax!ken
 * Will only compress regular files (no directories), added a magic number
 * header (plus an undocumented -n flag to handle old files without headers),
 * added -f flag to force overwriting of possibly existing destination file,
 * otherwise the user is prompted for a response.  Will tack on a .Z to a
 * filename if it doesn't have one when decompressing.  Will only replace
 * file if it was compressed.
 *
 * Revision 1.9  84/08/16  17:28:00  turtlevax!ken
 * Removed scanargs(), getopt(), added .Z extension and unlimited number of
 * filenames to compress.  Flags may be clustered (-Ddvb12) or separated
 * (-D -d -v -b 12), or combination thereof.  Modes and other status is
 * copied with copystat().  -O bug for 4.2 seems to have disappeared with
 * 1.8.
 *
 * Revision 1.8  84/08/09  23:15:00  joe
 * Made it compatible with vax version, installed jim's fixes/enhancements
 *
 * Revision 1.6  84/08/01  22:08:00  joe
 * Sped up algorithm significantly by sorting the compress chain.
 *
 * Revision 1.5  84/07/13  13:11:00  srd
 * Added C version of vax asm routines.  Changed structure to arrays to
 * save much memory.  Do unsigned compares where possible (faster on
 * Perkin-Elmer)
 *
 * Revision 1.4  84/07/05  03:11:11  thomas
 * Clean up the code a little and lint it.  (Lint complains about all
 * the regs used in the asm, but I'm not going to "fix" this.)
 *
 * Revision 1.3  84/07/05  02:06:54  thomas
 * Minor fixes.
 *
 * Revision 1.2  84/07/05  00:27:27  thomas
 * Add variable bit length output.
 *
 */
static char rcs_ident[] = "$Header: compress.c,v 4.0 85/07/30 12:50:00 joe Release $";

#include <stdio.h>
#include <ctype.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef notdef
#include <sys/ioctl.h>
#endif

#define ARGVAL() (*++(*argv) || (--argc && *++argv))

int n_bits;				/* number of bits/code */
int maxbits = BITS;			/* user settable max # bits/code */
code_int maxcode;			/* maximum code, given n_bits */
code_int maxmaxcode = 1 << BITS;	/* should NEVER generate this code */
#ifdef COMPATIBLE		/* But wrong! */
# define MAXCODE(n_bits)	(1 << (n_bits) - 1)
#else
# define MAXCODE(n_bits)	((1 << (n_bits)) - 1)
#endif /* COMPATIBLE */

#ifdef XENIX_16
count_int htab0[8192];
count_int htab1[8192];
count_int htab2[8192];
count_int htab3[8192];
count_int htab4[8192];
count_int htab5[8192];
count_int htab6[8192];
count_int htab7[8192];
count_int htab8[HSIZE-65536];
count_int * htab[9] = {
	htab0, htab1, htab2, htab3, htab4, htab5, htab6, htab7, htab8 };

#define htabof(i)	(htab[(i) >> 13][(i) & 0x1fff])
unsigned short code0tab[16384];
unsigned short code1tab[16384];
unsigned short code2tab[16384];
unsigned short code3tab[16384];
unsigned short code4tab[16384];
unsigned short * codetab[5] = {
	code0tab, code1tab, code2tab, code3tab, code4tab };

#define codetabof(i)	(codetab[(i) >> 14][(i) & 0x3fff])

#else	/* Normal machine */

#ifdef sel	/* gould base register braindamage */
/*NOBASE*/
count_int htab [HSIZE];
unsigned short codetab [HSIZE];
/*NOBASE*/
#else
count_int htab [HSIZE];
unsigned short codetab [HSIZE];
#endif sel

#define htabof(i)	htab[i]
#define codetabof(i)	codetab[i]
#endif	/* XENIX_16 */
code_int hsize = HSIZE;			/* for dynamic table sizing */
count_int fsize;

/*
 * To save much memory, we overlay the table used by compress() with those
 * used by decompress().  The tab_prefix table is the same size and type
 * as the codetab.  The tab_suffix table needs 2**BITS characters.  We
 * get this from the beginning of htab.  The output stack uses the rest
 * of htab, and contains characters.  There is plenty of room for any
 * possible stack (stack used to be 8000 characters).
 */

#define tab_prefixof(i)	codetabof(i)
#ifdef XENIX_16
# define tab_suffixof(i)	((char_type *)htab[(i)>>15])[(i) & 0x7fff]
# define de_stack		((char_type *)(htab2))
#else	/* Normal machine */
# define tab_suffixof(i)	((char_type *)(htab))[i]
# define de_stack		((char_type *)&tab_suffixof(1<<BITS))
#endif	/* XENIX_16 */

code_int free_ent = 0;			/* first unused entry */
int exit_stat = 0;			/* per-file status */
int perm_stat = 0;			/* permanent status */

code_int getcode();

Usage() {
#ifdef DEBUG
fprintf(stderr,"Usage: compress [-dDVfc] [-b maxbits] [file ...]\n");
}
int debug = 0;
#else
fprintf(stderr,"Usage: compress [-fvc] [-b maxbits] [file ...]\n");
}
#endif /* DEBUG */
int nomagic = 0;	/* Use a 3-byte magic number header, unless old file */
int zcat_flg = 0;	/* Write output on stdout, suppress messages */
int precious = 1;	/* Don't unlink output file on interrupt */
int quiet = 1;		/* don't tell me about compression */

/*
 * block compression parameters -- after all codes are used up,
 * and compression rate changes, start over.
 */
int block_compress = BLOCK_MASK;
int clear_flg = 0;
long int ratio = 0;
#define CHECK_GAP 10000	/* ratio check interval */
count_int checkpoint = CHECK_GAP;
/*
 * the next two codes should not be changed lightly, as they must not
 * lie within the contiguous general code space.
 */ 
#define FIRST	257	/* first free entry */
#define	CLEAR	256	/* table clear output code */

int force = 0;
char ofname [100];
#ifdef DEBUG
int verbose = 0;
#endif /* DEBUG */
int (*oldint)();
int bgnd_flag;

int do_decomp = 0;

/*****************************************************************
 * TAG( main )
 *
 * Algorithm from "A Technique for High Performance Data Compression",
 * Terry A. Welch, IEEE Computer Vol 17, No 6 (June 1984), pp 8-19.
 *
 * Usage: compress [-dfvc] [-b bits] [file ...]
 * Inputs:
 *	-d:	    If given, decompression is done instead.
 *
 *      -c:         Write output on stdout, don't remove original.
 *
 *      -b:         Parameter limits the max number of bits/code.
 *
 *	-f:	    Forces output file to be generated, even if one already
 *		    exists, and even if no space is saved by compressing.
 *		    If -f is not used, the user will be prompted if stdin is
 *		    a tty, otherwise, the output file will not be overwritten.
 *
 *      -v:	    Write compression statistics
 *
 * 	file ...:   Files to be compressed.  If none specified, stdin
 *		    is used.
 * Outputs:
 *	file.Z:	    Compressed form of file with same mode, owner, and utimes
 * 	or stdout   (if stdin used as input)
 *
 * Assumptions:
 *	When filenames are given, replaces with the compressed version
 *	(.Z suffix) only if the file decreases in size.
 * Algorithm:
 * 	Modified Lempel-Ziv method (LZW).  Basically finds common
 * substrings and replaces them with a variable size code.  This is
 * deterministic, and can be done on the fly.  Thus, the decompression
 * procedure needs no input table, but tracks the way the table was built.
 */

main( argc, argv )
register int argc; char **argv;
{
    int overwrite = 0;	/* Do not overwrite unless given -f flag */
    char tempname[100];
    char **filelist, **fileptr;
    char *cp, *rindex(), *malloc();
    struct stat statbuf;
    extern onintr(), oops();

    /* This bg check only works for sh. */
    if ( (oldint = signal ( SIGINT, SIG_IGN )) != SIG_IGN ) {
	signal ( SIGINT, onintr );
	signal ( SIGSEGV, oops );
    }
    bgnd_flag = oldint != SIG_DFL;
#ifdef notdef     /* This works for csh but we don't want it. */
    { int tgrp;
    if (bgnd_flag == 0 && ioctl(2, TIOCGPGRP, (char *)&tgrp) == 0 &&
      getpgrp(0) != tgrp)
	bgnd_flag = 1;
    }
#endif
    
#ifdef COMPATIBLE
    nomagic = 1;	/* Original didn't have a magic number */
#endif /* COMPATIBLE */

    filelist = fileptr = (char **)(malloc(argc * sizeof(*argv)));
    *filelist = NULL;

    if((cp = rindex(argv[0], '/')) != 0) {
	cp++;
    } else {
	cp = argv[0];
    }
    if(strcmp(cp, "uncompress") == 0) {
	do_decomp = 1;
    } else if(strcmp(cp, "zcat") == 0) {
	do_decomp = 1;
	zcat_flg = 1;
    }

#ifdef BSD4_2
    /* 4.2BSD dependent - take it out if not */
    setlinebuf( stderr );
#endif /* BSD4_2 */

    /* Argument Processing
     * All flags are optional.
     * -D => debug
     * -V => print Version; debug verbose
     * -d => do_decomp
     * -v => unquiet
     * -f => force overwrite of output file
     * -n => no header: useful to uncompress old files
     * -b maxbits => maxbits.  If -b is specified, then maxbits MUST be
     *	    given also.
     * -c => cat all output to stdout
     * -C => generate output compatible with compress 2.0.
     * if a string is left, must be an input filename.
     */
    for (argc--, argv++; argc > 0; argc--, argv++) {
	if (**argv == '-') {	/* A flag argument */
	    while (*++(*argv)) {	/* Process all flags in this arg */
		switch (**argv) {
#ifdef DEBUG
		    case 'D':
			debug = 1;
			break;
		    case 'V':
			verbose = 1;
			version();
			break;
#else
		    case 'V':
			version();
			break;
#endif /* DEBUG */
		    case 'v':
			quiet = 0;
			break;
		    case 'd':
			do_decomp = 1;
			break;
		    case 'f':
		    case 'F':
			overwrite = 1;
			force = 1;
			break;
		    case 'n':
			nomagic = 1;
			break;
		    case 'C':
			block_compress = 0;
			break;
		    case 'b':
			if (!ARGVAL()) {
			    fprintf(stderr, "Missing maxbits\n");
			    Usage();
			    exit(1);
			}
			maxbits = atoi(*argv);
			goto nextarg;
		    case 'c':
			zcat_flg = 1;
			break;
		    case 'q':
			quiet = 1;
			break;
		    default:
			fprintf(stderr, "Unknown flag: '%c'; ", **argv);
			Usage();
			exit(1);
		}
	    }
	}
	else {		/* Input file name */
	    *fileptr++ = *argv;	/* Build input file list */
	    *fileptr = NULL;
	    /* process nextarg; */
	}
	nextarg: continue;
    }

    if(maxbits < INIT_BITS) maxbits = INIT_BITS;
    if (maxbits > BITS) maxbits = BITS;
    maxmaxcode = 1 << maxbits;

    if (*filelist != NULL) {
	for (fileptr = filelist; *fileptr; fileptr++) {
	    exit_stat = 0;
	    if (do_decomp) {			/* DECOMPRESSION */
		/* Check for .Z suffix */
		if (strcmp(*fileptr + strlen(*fileptr) - 2, ".Z") != 0) {
		    /* No .Z: tack one on */
		    strcpy(tempname, *fileptr);
		    strcat(tempname, ".Z");
		    *fileptr = tempname;
		}
		/* Open input file */
		if ((freopen(*fileptr, "r", stdin)) == NULL) {
		    perror(*fileptr);
		    perm_stat = 1;
		    continue;
		}
		/* Check the magic number */
		if (nomagic == 0) {
		    if ((getchar() != (magic_header[0] & 0xFF))
		     || (getchar() != (magic_header[1] & 0xFF))) {
			fprintf(stderr, "%s: not in compressed format\n",
			    *fileptr);
		    continue;
		    }
		    maxbits = getchar();	/* set -b from file */
		    block_compress = maxbits & BLOCK_MASK;
		    maxbits &= BIT_MASK;
		    maxmaxcode = 1 << maxbits;
		    if(maxbits > BITS) {
			fprintf(stderr,
			"%s: compressed with %d bits, can only handle %d bits\n",
			*fileptr, maxbits, BITS);
			continue;
		    }
		}
		/* Generate output filename */
		strcpy(ofname, *fileptr);
		ofname[strlen(*fileptr) - 2] = '\0';  /* Strip off .Z */
	    } else {					/* COMPRESSION */
		if (strcmp(*fileptr + strlen(*fileptr) - 2, ".Z") == 0) {
		    	fprintf(stderr, "%s: already has .Z suffix -- no change\n",
			    *fileptr);
		    continue;
		}
		/* Open input file */
		if ((freopen(*fileptr, "r", stdin)) == NULL) {
		    perror(*fileptr);
		    perm_stat = 1;
		    continue;
		}
		stat ( *fileptr, &statbuf );
		fsize = (long) statbuf.st_size;
		/*
		 * tune hash table size for small files -- ad hoc,
		 * but the sizes match earlier #defines, which
		 * serve as upper bounds on the number of output codes. 
		 */
		hsize = HSIZE;
		if ( fsize < (1 << 12) )
		    hsize = min ( 5003, HSIZE );
		else if ( fsize < (1 << 13) )
		    hsize = min ( 9001, HSIZE );
		else if ( fsize < (1 << 14) )
		    hsize = min ( 18013, HSIZE );
		else if ( fsize < (1 << 15) )
		    hsize = min ( 35023, HSIZE );
		else if ( fsize < 47000 )
		    hsize = min ( 50021, HSIZE );

		/* Generate output filename */
		strcpy(ofname, *fileptr);
#ifndef BSD4_2		/* Short filenames */
		if ((cp=rindex(ofname,'/')) != NULL)	cp++;
		else					cp = ofname;
		if (strlen(cp) > 12) {
		    fprintf(stderr,"%s: filename too long to tack on .Z\n",cp);
		    continue;
		}
#endif  /* BSD4_2		Long filenames allowed */
		strcat(ofname, ".Z");
	    }
	    /* Check for overwrite of existing file */
	    if (overwrite == 0 && zcat_flg == 0) {
		if (stat(ofname, &statbuf) == 0) {
		    char response[2];
		    response[0] = 'n';
		    fprintf(stderr, "%s already exists;", ofname);
		    if (bgnd_flag == 0 && isatty(2)) {
			fprintf(stderr, " do you wish to overwrite %s (y or n)? ",
			ofname);
			fflush(stderr);
			read(2, response, 2);
			while (response[1] != '\n') {
			    if (read(2, response+1, 1) < 0) {	/* Ack! */
				perror("stderr"); break;
			    }
			}
		    }
		    if (response[0] != 'y') {
			fprintf(stderr, "\tnot overwritten\n");
			continue;
		    }
		}
	    }
	    if(zcat_flg == 0) {		/* Open output file */
		if (freopen(ofname, "w", stdout) == NULL) {
		    perror(ofname);
		    perm_stat = 1;
		    continue;
		}
		precious = 0;
		if(!quiet)
			fprintf(stderr, "%s: ", *fileptr);
	    }

	    /* Actually do the compression/decompression */
	    if (do_decomp == 0)	compress();
#ifndef DEBUG
	    else			decompress();
#else
	    else if (debug == 0)	decompress();
	    else			printcodes();
	    if (verbose)		dump_tab();
#endif /* DEBUG */
	    if(zcat_flg == 0) {
		copystat(*fileptr, ofname);	/* Copy stats */
		precious = 1;
		if((exit_stat == 1) || (!quiet))
			putc('\n', stderr);
	    }
	}
    } else {		/* Standard input */
	if (do_decomp == 0) {
		compress();
#ifdef DEBUG
		if(verbose)		dump_tab();
#endif /* DEBUG */
		if(!quiet)
			putc('\n', stderr);
	} else {
	    /* Check the magic number */
	    if (nomagic == 0) {
		if ((getchar()!=(magic_header[0] & 0xFF))
		 || (getchar()!=(magic_header[1] & 0xFF))) {
		    fprintf(stderr, "stdin: not in compressed format\n");
		    exit(1);
		}
		maxbits = getchar();	/* set -b from file */
		block_compress = maxbits & BLOCK_MASK;
		maxbits &= BIT_MASK;
		maxmaxcode = 1 << maxbits;
		fsize = 100000;		/* assume stdin large for USERMEM */
		if(maxbits > BITS) {
			fprintf(stderr,
			"stdin: compressed with %d bits, can only handle %d bits\n",
			maxbits, BITS);
			exit(1);
		}
	    }
#ifndef DEBUG
	    decompress();
#else
	    if (debug == 0)	decompress();
	    else		printcodes();
	    if (verbose)	dump_tab();
#endif /* DEBUG */
	}
    }
    exit(perm_stat ? perm_stat : exit_stat);
}

static int offset;
long int in_count = 1;			/* length of input */
long int bytes_out;			/* length of compressed output */
long int out_count = 0;			/* # of codes output (for debugging) */

/*
 * compress stdin to stdout
 *
 * Algorithm:  use open addressing double hashing (no chaining) on the 
 * prefix code / next character combination.  We do a variant of Knuth's
 * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
 * secondary probe.  Here, the modular division first probe is gives way
 * to a faster exclusive-or manipulation.  Also do block compression with
 * an adaptive reset, whereby the code table is cleared when the compression
 * ratio decreases, but after the table fills.  The variable-length output
 * codes are re-sized at this point, and a special CLEAR code is generated
 * for the decompressor.  Late addition:  construct the table according to
 * file size for noticeable speed improvement on small files.  Please direct
 * questions about this implementation to ames!jaw.
 */

compress() {
    register long fcode;
    register code_int i = 0;
    register int c;
    register code_int ent;
#ifdef XENIX_16
    register code_int disp;
#else	/* Normal machine */
    register int disp;
#endif
    register code_int hsize_reg;
    register int hshift;

#ifndef COMPATIBLE
    if (nomagic == 0) {
	putchar(magic_header[0]); putchar(magic_header[1]);
	putchar((char)(maxbits | block_compress));
	if(ferror(stdout))
		writeerr();
    }
#endif /* COMPATIBLE */

    offset = 0;
    bytes_out = 3;		/* includes 3-byte header mojo */
    out_count = 0;
    clear_flg = 0;
    ratio = 0;
    in_count = 1;
    checkpoint = CHECK_GAP;
    maxcode = MAXCODE(n_bits = INIT_BITS);
    free_ent = ((block_compress) ? FIRST : 256 );

    ent = getchar ();

    hshift = 0;
    for ( fcode = (long) hsize;  fcode < 65536L; fcode *= 2L )
    	hshift++;
    hshift = 8 - hshift;		/* set hash code range bound */

    hsize_reg = hsize;
    cl_hash( (count_int) hsize_reg);		/* clear hash table */

#ifdef SIGNED_COMPARE_SLOW
    while ( (c = getchar()) != (unsigned) EOF ) {
#else
    while ( (c = getchar()) != EOF ) {
#endif
	in_count++;
	fcode = (long) (((long) c << maxbits) + ent);
 	i = ((c << hshift) ^ ent);	/* xor hashing */

	if ( htabof (i) == fcode ) {
	    ent = codetabof (i);
	    continue;
	} else if ( (long)htabof (i) < 0 )	/* empty slot */
	    goto nomatch;
 	disp = hsize_reg - i;		/* secondary hash (after G. Knott) */
	if ( i == 0 )
	    disp = 1;
probe:
	if ( (i -= disp) < 0 )
	    i += hsize_reg;

	if ( htabof (i) == fcode ) {
	    ent = codetabof (i);
	    continue;
	}
	if ( (long)htabof (i) > 0 ) 
	    goto probe;
nomatch:
	output ( (code_int) ent );
	out_count++;
 	ent = c;
#ifdef SIGNED_COMPARE_SLOW
	if ( (unsigned) free_ent < (unsigned) maxmaxcode) {
#else
	if ( free_ent < maxmaxcode ) {
#endif
 	    codetabof (i) = free_ent++;	/* code -> hashtable */
	    htabof (i) = fcode;
	}
	else if ( (count_int)in_count >= checkpoint && block_compress )
	    cl_block ();
    }
    /*
     * Put out the final code.
     */
    output( (code_int)ent );
    out_count++;
    output( (code_int)-1 );

    /*
     * Print out stats on stderr
     */
    if(zcat_flg == 0 && !quiet) {
#ifdef DEBUG
	fprintf( stderr,
		"%ld chars in, %ld codes (%ld bytes) out, compression factor: ",
		in_count, out_count, bytes_out );
	prratio( stderr, in_count, bytes_out );
	fprintf( stderr, "\n");
	fprintf( stderr, "\tCompression as in compact: " );
	prratio( stderr, in_count-bytes_out, in_count );
	fprintf( stderr, "\n");
	fprintf( stderr, "\tLargest code (of last block) was %d (%d bits)\n",
		free_ent - 1, n_bits );
#else /* !DEBUG */
	fprintf( stderr, "Compression: " );
	prratio( stderr, in_count-bytes_out, in_count );
#endif /* DEBUG */
    }
    if(bytes_out > in_count)	/* exit(2) if no savings */
	exit_stat = 2;
    return;
}

/*****************************************************************
 * TAG( output )
 *
 * Output the given code.
 * Inputs:
 * 	code:	A n_bits-bit integer.  If == -1, then EOF.  This assumes
 *		that n_bits =< (long)wordsize - 1.
 * Outputs:
 * 	Outputs code to the file.
 * Assumptions:
 *	Chars are 8 bits long.
 * Algorithm:
 * 	Maintain a BITS character long buffer (so that 8 codes will
 * fit in it exactly).  Use the VAX insv instruction to insert each
 * code in turn.  When the buffer fills up empty it and start over.
 */

static char buf[BITS];

#ifndef vax
char_type lmask[9] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
char_type rmask[9] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
#endif /* vax */

output( code )
code_int  code;
{
#ifdef DEBUG
    static int col = 0;
#endif /* DEBUG */

    /*
     * On the VAX, it is important to have the register declarations
     * in exactly the order given, or the asm will break.
     */
    register int r_off = offset, bits= n_bits;
    register char * bp = buf;

#ifdef DEBUG
	if ( verbose )
	    fprintf( stderr, "%5d%c", code,
		    (col+=6) >= 74 ? (col = 0, '\n') : ' ' );
#endif /* DEBUG */
    if ( code >= 0 ) {
#ifdef vax
	/* VAX DEPENDENT!! Implementation on other machines is below.
	 *
	 * Translation: Insert BITS bits from the argument starting at
	 * offset bits from the beginning of buf.
	 */
	0;	/* Work around for pcc -O bug with asm and if stmt */
	asm( "insv	4(ap),r11,r10,(r9)" );
#else /* not a vax */
/* 
 * byte/bit numbering on the VAX is simulated by the following code
 */
	/*
	 * Get to the first byte.
	 */
	bp += (r_off >> 3);
	r_off &= 7;
	/*
	 * Since code is always >= 8 bits, only need to mask the first
	 * hunk on the left.
	 */
	*bp = (*bp & rmask[r_off]) | (code << r_off) & lmask[r_off];
	bp++;
	bits -= (8 - r_off);
	code >>= 8 - r_off;
	/* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
	if ( bits >= 8 ) {
	    *bp++ = code;
	    code >>= 8;
	    bits -= 8;
	}
	/* Last bits. */
	if(bits)
	    *bp = code;
#endif /* vax */
	offset += n_bits;
	if ( offset == (n_bits << 3) ) {
	    bp = buf;
	    bits = n_bits;
	    bytes_out += bits;
	    do
		putchar(*bp++);
	    while(--bits);
	    offset = 0;
	}

	/*
	 * If the next entry is going to be too big for the code size,
	 * then increase it, if possible.
	 */
	if ( free_ent > maxcode || (clear_flg > 0))
	{
	    /*
	     * Write the whole buffer, because the input side won't
	     * discover the size increase until after it has read it.
	     */
	    if ( offset > 0 ) {
		if( fwrite( buf, 1, n_bits, stdout ) != n_bits)
			writeerr();
		bytes_out += n_bits;
	    }
	    offset = 0;

	    if ( clear_flg ) {
    	        maxcode = MAXCODE (n_bits = INIT_BITS);
	        clear_flg = 0;
	    }
	    else {
	    	n_bits++;
	    	if ( n_bits == maxbits )
		    maxcode = maxmaxcode;
	    	else
		    maxcode = MAXCODE(n_bits);
	    }
#ifdef DEBUG
	    if ( debug ) {
		fprintf( stderr, "\nChange to %d bits\n", n_bits );
		col = 0;
	    }
#endif /* DEBUG */
	}
    } else {
	/*
	 * At EOF, write the rest of the buffer.
	 */
	if ( offset > 0 )
	    fwrite( buf, 1, (offset + 7) / 8, stdout );
	bytes_out += (offset + 7) / 8;
	offset = 0;
	fflush( stdout );
#ifdef DEBUG
	if ( verbose )
	    fprintf( stderr, "\n" );
#endif /* DEBUG */
	if( ferror( stdout ) )
		writeerr();
    }
}

/*
 * Decompress stdin to stdout.  This routine adapts to the codes in the
 * file building the "string" table on-the-fly; requiring no table to
 * be stored in the compressed file.  The tables used herein are shared
 * with those of the compress() routine.  See the definitions above.
 */

decompress() {
    register char_type *stackp;
    register int finchar;
    register code_int code, oldcode, incode;

    /*
     * As above, initialize the first 256 entries in the table.
     */
    maxcode = MAXCODE(n_bits = INIT_BITS);
    for ( code = 255; code >= 0; code-- ) {
	tab_prefixof(code) = 0;
	tab_suffixof(code) = (char_type)code;
    }
    free_ent = ((block_compress) ? FIRST : 256 );

    finchar = oldcode = getcode();
    if(oldcode == -1)	/* EOF already? */
	return;			/* Get out of here */
    putchar( (char)finchar );		/* first code must be 8 bits = char */
    if(ferror(stdout))		/* Crash if can't write */
	writeerr();
    stackp = de_stack;

    while ( (code = getcode()) > -1 ) {

	if ( (code == CLEAR) && block_compress ) {
	    for ( code = 255; code >= 0; code-- )
		tab_prefixof(code) = 0;
	    clear_flg = 1;
	    free_ent = FIRST - 1;
	    if ( (code = getcode ()) == -1 )	/* O, untimely death! */
		break;
	}
	incode = code;
	/*
	 * Special case for KwKwK string.
	 */
	if ( code >= free_ent ) {
            *stackp++ = finchar;
	    code = oldcode;
	}

	/*
	 * Generate output characters in reverse order
	 */
#ifdef SIGNED_COMPARE_SLOW
	while ( ((unsigned long)code) >= ((unsigned long)256) ) {
#else
	while ( code >= 256 ) {
#endif
	    *stackp++ = tab_suffixof(code);
	    code = tab_prefixof(code);
	}
	*stackp++ = finchar = tab_suffixof(code);

	/*
	 * And put them out in forward order
	 */
	do
	    putchar ( *--stackp );
	while ( stackp > de_stack );

	/*
	 * Generate the new entry.
	 */
	if ( (code=free_ent) < maxmaxcode ) {
	    tab_prefixof(code) = (unsigned short)oldcode;
	    tab_suffixof(code) = finchar;
	    free_ent = code+1;
	} 
	/*
	 * Remember previous code.
	 */
	oldcode = incode;
    }
    fflush( stdout );
    if(ferror(stdout))
	writeerr();
}

/*****************************************************************
 * TAG( getcode )
 *
 * Read one code from the standard input.  If EOF, return -1.
 * Inputs:
 * 	stdin
 * Outputs:
 * 	code or -1 is returned.
 */

code_int
getcode() {
    /*
     * On the VAX, it is important to have the register declarations
     * in exactly the order given, or the asm will break.
     */
    register code_int code;
    static int offset = 0, size = 0;
    static char_type buf[BITS];
    register int r_off, bits;
    register char_type *bp = buf;

    if ( clear_flg > 0 || offset >= size || free_ent > maxcode ) {
	/*
	 * If the next entry will be too big for the current code
	 * size, then we must increase the size.  This implies reading
	 * a new buffer full, too.
	 */
	if ( free_ent > maxcode ) {
	    n_bits++;
	    if ( n_bits == maxbits )
		maxcode = maxmaxcode;	/* won't get any bigger now */
	    else
		maxcode = MAXCODE(n_bits);
	}
	if ( clear_flg > 0) {
    	    maxcode = MAXCODE (n_bits = INIT_BITS);
	    clear_flg = 0;
	}
	size = fread( buf, 1, n_bits, stdin );
	if ( size <= 0 )
	    return -1;			/* end of file */
	offset = 0;
	/* Round size down to integral number of codes */
	size = (size << 3) - (n_bits - 1);
    }
    r_off = offset;
    bits = n_bits;
#ifdef vax
    asm( "extzv   r10,r9,(r8),r11" );
#else /* not a vax */
	/*
	 * Get to the first byte.
	 */
	bp += (r_off >> 3);
	r_off &= 7;
	/* Get first part (low order bits) */
#ifdef NO_UCHAR
	code = ((*bp++ >> r_off) & rmask[8 - r_off]) & 0xff;
#else
	code = (*bp++ >> r_off);
#endif /* NO_UCHAR */
	bits -= (8 - r_off);
	r_off = 8 - r_off;		/* now, offset into code word */
	/* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
	if ( bits >= 8 ) {
#ifdef NO_UCHAR
	    code |= (*bp++ & 0xff) << r_off;
#else
	    code |= *bp++ << r_off;
#endif /* NO_UCHAR */
	    r_off += 8;
	    bits -= 8;
	}
	/* high order bits. */
	code |= (*bp & rmask[bits]) << r_off;
#endif /* vax */
    offset += n_bits;

    return code;
}

char *
rindex(s, c)		/* For those who don't have it in libc.a */
register char *s, c;
{
	char *p;
	for (p = NULL; *s; s++)
	    if (*s == c)
		p = s;
	return(p);
}

#ifdef DEBUG
printcodes()
{
    /*
     * Just print out codes from input file.  For debugging.
     */
    code_int code;
    int col = 0, bits;

    bits = n_bits = INIT_BITS;
    maxcode = MAXCODE(n_bits);
    free_ent = ((block_compress) ? FIRST : 256 );
    while ( ( code = getcode() ) >= 0 ) {
	if ( (code == CLEAR) && block_compress ) {
   	    free_ent = FIRST - 1;
   	    clear_flg = 1;
	}
	else if ( free_ent < maxmaxcode )
	    free_ent++;
	if ( bits != n_bits ) {
	    fprintf(stderr, "\nChange to %d bits\n", n_bits );
	    bits = n_bits;
	    col = 0;
	}
	fprintf(stderr, "%5d%c", code, (col+=6) >= 74 ? (col = 0, '\n') : ' ' );
    }
    putc( '\n', stderr );
    exit( 0 );
}

code_int sorttab[1<<BITS];	/* sorted pointers into htab */

dump_tab()	/* dump string table */
{
    register int i, first;
    register ent;
#define STACK_SIZE	15000
    int stack_top = STACK_SIZE;
    register c;

    if(do_decomp == 0) {	/* compressing */
	register int flag = 1;

	for(i=0; i<hsize; i++) {	/* build sort pointers */
		if((long)htabof(i) >= 0) {
			sorttab[codetabof(i)] = i;
		}
	}
	first = block_compress ? FIRST : 256;
	for(i = first; i < free_ent; i++) {
		fprintf(stderr, "%5d: \"", i);
		de_stack[--stack_top] = '\n';
		de_stack[--stack_top] = '"';
		stack_top = in_stack((htabof(sorttab[i])>>maxbits)&0xff, 
                                     stack_top);
		for(ent=htabof(sorttab[i]) & ((1<<maxbits)-1);
		    ent > 256;
		    ent=htabof(sorttab[ent]) & ((1<<maxbits)-1)) {
			stack_top = in_stack(htabof(sorttab[ent]) >> maxbits,
						stack_top);
		}
		stack_top = in_stack(ent, stack_top);
		fwrite( &de_stack[stack_top], 1, STACK_SIZE-stack_top, stderr);
	   	stack_top = STACK_SIZE;
	}
   } else if(!debug) {	/* decompressing */

       for ( i = 0; i < free_ent; i++ ) {
	   ent = i;
	   c = tab_suffixof(ent);
	   if ( isascii(c) && isprint(c) )
	       fprintf( stderr, "%5d: %5d/'%c'  \"",
			   ent, tab_prefixof(ent), c );
	   else
	       fprintf( stderr, "%5d: %5d/\\%03o \"",
			   ent, tab_prefixof(ent), c );
	   de_stack[--stack_top] = '\n';
	   de_stack[--stack_top] = '"';
	   for ( ; ent != NULL;
		   ent = (ent >= FIRST ? tab_prefixof(ent) : NULL) ) {
	       stack_top = in_stack(tab_suffixof(ent), stack_top);
	   }
	   fwrite( &de_stack[stack_top], 1, STACK_SIZE - stack_top, stderr );
	   stack_top = STACK_SIZE;
       }
    }
}

int
in_stack(c, stack_top)
	register c, stack_top;
{
	if ( (isascii(c) && isprint(c) && c != '\\') || c == ' ' ) {
	    de_stack[--stack_top] = c;
	} else {
	    switch( c ) {
	    case '\n': de_stack[--stack_top] = 'n'; break;
	    case '\t': de_stack[--stack_top] = 't'; break;
	    case '\b': de_stack[--stack_top] = 'b'; break;
	    case '\f': de_stack[--stack_top] = 'f'; break;
	    case '\r': de_stack[--stack_top] = 'r'; break;
	    case '\\': de_stack[--stack_top] = '\\'; break;
	    default:
	 	de_stack[--stack_top] = '0' + c % 8;
	 	de_stack[--stack_top] = '0' + (c / 8) % 8;
	 	de_stack[--stack_top] = '0' + c / 64;
	 	break;
	    }
	    de_stack[--stack_top] = '\\';
	}
	return stack_top;
}
#endif /* DEBUG */

writeerr()
{
    perror ( ofname );
    unlink ( ofname );
    exit ( 1 );
}

copystat(ifname, ofname)
char *ifname, *ofname;
{
    struct stat statbuf;
    int mode;
    time_t timep[2];

    fclose(stdout);
    if (stat(ifname, &statbuf)) {		/* Get stat on input file */
	perror(ifname);
	return;
    }
    if ((statbuf.st_mode & S_IFMT/*0170000*/) != S_IFREG/*0100000*/) {
	if(quiet)
	    	fprintf(stderr, "%s: ", ifname);
	fprintf(stderr, " -- not a regular file: unchanged");
	exit_stat = 1;
	perm_stat = 1;
    } else if (statbuf.st_nlink > 1) {
	if(quiet)
	    	fprintf(stderr, "%s: ", ifname);
	fprintf(stderr, " -- has %d other links: unchanged",
		statbuf.st_nlink - 1);
	exit_stat = 1;
	perm_stat = 1;
    } else if (exit_stat == 2 && (!force)) { /* No compression: remove file.Z */
	if(!quiet)
		fprintf(stderr, " -- file unchanged");
    } else {			/* ***** Successful Compression ***** */
	exit_stat = 0;
	mode = statbuf.st_mode & 07777;
	if (chmod(ofname, mode))		/* Copy modes */
	    perror(ofname);
	chown(ofname, statbuf.st_uid, statbuf.st_gid);	/* Copy ownership */
	timep[0] = statbuf.st_atime;
	timep[1] = statbuf.st_mtime;
	utime(ofname, timep);	/* Update last accessed and modified times */
	if (unlink(ifname))	/* Remove input file */
	    perror(ifname);
	if(!quiet)
		fprintf(stderr, " -- replaced with %s", ofname);
	return;		/* Successful return */
    }

    /* Unsuccessful return -- one of the tests failed */
    if (unlink(ofname))
	perror(ofname);
}

onintr ( )
{
    if (!precious)
	unlink ( ofname );
    exit ( 1 );
}

oops ( )	/* wild pointer -- assume bad input */
{
    if ( do_decomp ) 
    	fprintf ( stderr, "uncompress: corrupt input\n" );
    unlink ( ofname );
    exit ( 1 );
}

cl_block ()		/* table clear for block compress */
{
    register long int rat;

    checkpoint = in_count + CHECK_GAP;
#ifdef DEBUG
	if ( debug ) {
    		fprintf ( stderr, "count: %ld, ratio: ", in_count );
     		prratio ( stderr, in_count, bytes_out );
		fprintf ( stderr, "\n");
	}
#endif /* DEBUG */

    if(in_count > 0x007fffff) {	/* shift will overflow */
	rat = bytes_out >> 8;
	if(rat == 0) {		/* Don't divide by zero */
	    rat = 0x7fffffff;
	} else {
	    rat = in_count / rat;
	}
    } else {
	rat = (in_count << 8) / bytes_out;	/* 8 fractional bits */
    }
    if ( rat > ratio ) {
	ratio = rat;
    } else {
	ratio = 0;
#ifdef DEBUG
	if(verbose)
		dump_tab();	/* dump string table */
#endif
 	cl_hash ( (count_int) hsize );
	free_ent = FIRST;
	clear_flg = 1;
	output ( (code_int) CLEAR );
#ifdef DEBUG
	if(debug)
    		fprintf ( stderr, "clear\n" );
#endif /* DEBUG */
    }
}

cl_hash(hsize)		/* reset code table */
	register count_int hsize;
{
#ifndef XENIX_16	/* Normal machine */
	register count_int *htab_p = htab+hsize;
#else
	register j;
	register long k = hsize;
	register count_int *htab_p;
#endif
	register long i;
	register long m1 = -1;

#ifdef XENIX_16
    for(j=0; j<=8 && k>=0; j++,k-=8192) {
	i = 8192;
	if(k < 8192) {
		i = k;
	}
	htab_p = &(htab[j][i]);
	i -= 16;
	if(i > 0) {
#else
	i = hsize - 16;
#endif
 	do {				/* might use Sys V memset(3) here */
		*(htab_p-16) = m1;
		*(htab_p-15) = m1;
		*(htab_p-14) = m1;
		*(htab_p-13) = m1;
		*(htab_p-12) = m1;
		*(htab_p-11) = m1;
		*(htab_p-10) = m1;
		*(htab_p-9) = m1;
		*(htab_p-8) = m1;
		*(htab_p-7) = m1;
		*(htab_p-6) = m1;
		*(htab_p-5) = m1;
		*(htab_p-4) = m1;
		*(htab_p-3) = m1;
		*(htab_p-2) = m1;
		*(htab_p-1) = m1;
		htab_p -= 16;
	} while ((i -= 16) >= 0);
#ifdef XENIX_16
	}
    }
#endif
    	for ( i += 16; i > 0; i-- )
		*--htab_p = m1;
}

prratio(stream, num, den)
FILE *stream;
long int num, den;
{
	register int q;			/* Doesn't need to be long */

	if(num > 214748L) {		/* 2147483647/10000 */
		q = num / (den / 10000L);
	} else {
		q = 10000L * num / den;		/* Long calculations, though */
	}
	if (q < 0) {
		putc('-', stream);
		q = -q;
	}
	fprintf(stream, "%d.%02d%%", q / 100, q % 100);
}

version()
{
	fprintf(stderr, "%s, Berkeley 5.9 5/11/86\n", rcs_ident);
	fprintf(stderr, "Options: ");
#ifdef vax
	fprintf(stderr, "vax, ");
#endif
#ifdef NO_UCHAR
	fprintf(stderr, "NO_UCHAR, ");
#endif
#ifdef SIGNED_COMPARE_SLOW
	fprintf(stderr, "SIGNED_COMPARE_SLOW, ");
#endif
#ifdef XENIX_16
	fprintf(stderr, "XENIX_16, ");
#endif
#ifdef COMPATIBLE
	fprintf(stderr, "COMPATIBLE, ");
#endif
#ifdef DEBUG
	fprintf(stderr, "DEBUG, ");
#endif
#ifdef BSD4_2
	fprintf(stderr, "BSD4_2, ");
#endif
	fprintf(stderr, "BITS = %d\n", BITS);
}
@EOF

chmod 440 compress.c

echo x - usermem.sh
cat >usermem.sh <<'@EOF'
#!/bin/sh -
#
#	@(#)usermem.sh	5.4 (Berkeley) 9/17/85
#
: This shell script snoops around to find the maximum amount of available
: user memory.  These variables need to be set only if there is no
: /usr/adm/messages.  KMEM, UNIX, and CLICKSIZE can be set on the command
: line, if desired, e.g. UNIX=/unix
KMEM=/dev/kmem		# User needs read access to KMEM
UNIX=
# VAX			CLICKSIZE=512,	UNIX=/vmunix
# PDP-11		CLICKSIZE=64,	UNIX=/unix
# CADLINC 68000		CLICKSIZE=4096,	UNIX=/unix
# Perkin-Elmer 3205	CLICKSIZE=4096,	UNIX=/edition7
# Perkin-Elmer all others, CLICKSIZE=2048, UNIX=/edition7
CLICKSIZE=512
eval $*

if test -n "$UNIX"
then
    : User must have specified it already.
elif test -r /vmunix
then
    UNIX=/vmunix
    CLICKSIZE=512	# Probably VAX
elif test -r /edition7
then
    UNIX=/edition7
    CLICKSIZE=2048	# Perkin-Elmer: change to 4096 on a 3205
elif test -r /unix
then
    UNIX=/unix		# Could be anything
fi

SIZE=0
# messages: probably the most transportable
if test -r /usr/adm/messages -a -s /usr/adm/messages
then
    SIZE=`grep avail /usr/adm/messages | sed -n '$s/.*[ 	]//p'`
fi

if test 0$SIZE -le 0		# no SIZE in /usr/adm/messages
then
    if test -r $KMEM		# Readable KMEM
    then
	if test -n "$UNIX"
	then
	    SIZE=`echo maxmem/D | adb $UNIX $KMEM | sed -n '$s/.*[ 	]//p'`
	    if test 0$SIZE -le 0
	    then
		SIZE=`echo physmem/D | adb $UNIX $KMEM | sed -n '$s/.*[ 	]//p'`
	    fi
	    SIZE=`expr 0$SIZE '*' $CLICKSIZE`
	fi
    fi
fi

case $UNIX in
    /vmunix)		# Assume 4.2bsd: check for resource limits
	MAXSIZE=`csh -c limit | awk 'BEGIN	{ MAXSIZE = 1000000 }
/datasize|memoryuse/ && NF == 3	{ if ($2 < MAXSIZE) MAXSIZE = $2 }
END	{ print MAXSIZE * 1000 }'`
	if test $MAXSIZE -lt $SIZE
	then
	    SIZE=$MAXSIZE
	fi
	;;
esac

if test 0$SIZE -le 0
then
    echo 0;exit 1
else
    echo $SIZE
fi
@EOF

chmod 440 usermem.sh

exit 0
