Mod.sources:  Volume 2, Issue 28
Submitted by: vax135!petsd!joe (Joe Orost)

#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
#	compress.1
#	compress.c
#	Makefile
#	usermem
# This archive created: Thu Aug  1 11:51:23 1985
export PATH; PATH=/bin:$PATH
echo shar: extracting "'compress.1'" '(5147 characters)'
if test -f 'compress.1'
then
	echo shar: will not over-write existing file "'compress.1'"
else
sed 's/^X//' << \SHAR_EOF > 'compress.1'
X.PU
X.TH COMPRESS 1 local
X.SH NAME
compress, uncompress, zcat \- compress and expand data
X.SH SYNOPSIS
X.ll +8
X.B compress
[
X.B \-f
] [
X.B \-v
] [
X.B \-c
] [
X.B \-V
] [
X.B \-b
X.I bits
] [
X.I "name \&..."
]
X.ll -8
X.br
X.B uncompress
[
X.B \-f
] [
X.B \-v
] [
X.B \-c
] [
X.B \-V
] [
X.I "name \&..."
]
X.br
X.B zcat
[
X.B \-V
] [
X.I "name \&..."
]
X.SH DESCRIPTION
X.I Compress
reduces the size of the named files using adaptive Lempel-Ziv coding.
Whenever possible,
each file is replaced by one with the extension
X.B "\&.Z,"
while keeping the same ownership modes, access and modification times.
If no files are specified, the standard input is compressed to the
standard output.
Compressed files can be restored to their original form using
X.I uncompress
or
X.I zcat.
X.PP
The
X.B \-f
option will force compression of
X.I name.
This is useful for compressing an entire directory,
even if some of the files do not actually shrink.
If
X.B \-f
is not given and
X.I compress
is run in the foreground,
the user is prompted as to whether an existing file should be overwritten.
X.PP
The
X.B \-c
option makes
X.I compress/uncompress
write to the standard output; no files are changed.
The nondestructive behavior of
X.I zcat
is identical to that of
X.I uncompress
X.B \-c.
X.PP
X.I Compress
uses the modified Lempel-Ziv algorithm popularized in
"A Technique for High Performance Data Compression",
Terry A. Welch,
X.I "IEEE Computer,"
vol. 17, no. 6 (June 1984), pp. 8-19.
Common substrings in the file are first replaced by 9-bit codes 257 and up.
When code 512 is reached, the algorithm switches to 10-bit codes and
continues to use more bits until the
limit specified by the
X.B \-b
flag is reached (default 16).
X.I Bits
must be between 9 and 16.  The default can be changed in the source to allow
X.I compress
to be run on a smaller machine.
X.PP
After the
X.I bits
limit is attained,
X.I compress
periodically checks the compression ratio.  If it is increasing,
X.I compress
continues to use the existing code dictionary.  However,
if the compression ratio decreases,
X.I compress
discards the table of substrings and rebuilds it from scratch.  This allows
the algorithm to adapt to the next "block" of the file.
X.PP
Note that the
X.B \-b
flag is omitted for
X.I uncompress,
since the 
X.I bits
parameter specified during compression
is encoded within the output, along with
a magic number to ensure that neither decompression of random data nor
recompression of compressed data is attempted. 
X.PP
X.ne 8
The amount of compression obtained depends on the size of the
input, the number of
X.I bits
per code, and the distribution of common substrings.
Typically, text such as source code or English
is reduced by 50\-60%.
Compression is generally much better than that achieved by
Huffman coding (as used in
X.IR pack ),
or adaptive Huffman coding
X.RI ( compact ),
and takes less time to compute.
X.PP
Under the
X.B \-v
option,
a message is printed yielding the percentage of
reduction for each file compressed.
X.PP
If the
X.B \-V
option is specified, the current version and compile options are printed on
stderr.
X.PP
Exit status is normally 0;
if the last file is larger after (attempted) compression, the status is 2;
if an error occurs, exit status is 1.
X.SH "SEE ALSO"
pack(1), compact(1)
X.SH "DIAGNOSTICS"
Usage: compress [\-dfvcV] [\-b maxbits] [file ...]
X.in +8
Invalid options were specified on the command line.
X.in -8
Missing maxbits
X.in +8
Maxbits must follow
X.BR \-b \.
X.in -8
X.IR file :
not in compressed format
X.in +8
The file specified to
X.I uncompress
has not been compressed.
X.in -8
X.IR file :
compressed with 
X.I xx
bits, can only handle 
X.I yy
bits
X.in +8
X.I File
was compressed by a program that could deal with
more 
X.I bits
than the compress code on this machine.
Recompress the file with smaller
X.IR bits \.
X.in -8
X.IR file :
already has .Z suffix -- no change
X.in +8
The file is assumed to be already compressed.
Rename the file and try again.
X.in -8
X.IR file :
filename too long to tack on .Z
X.in +8
The file cannot be compressed because its name is longer than
12 characters.
Rename and try again.
This message does not occur on BSD systems.
X.in -8
X.I file
already exists; do you wish to overwrite (y or n)?
X.in +8
Respond "y" if you want the output file to be replaced; "n" if not.
X.in -8
uncompress: corrupt input
X.in +8
A SIGSEGV violation was detected which usually means that the input file has
been corrupted.
X.in -8
Compression: 
X.I "xx.xx%"
X.in +8
Percentage of the input saved by compression.
(Relevant only for
X.BR \-v \.)
X.in -8
-- not a regular file: unchanged
X.in +8
When the input file is not a regular file,
(e.g. a directory), it is
left unaltered.
X.in -8
-- has 
X.I xx 
other links: unchanged
X.in +8
The input file has links; it is left unchanged.  See
X.IR ln "(1)"
for more information.
X.in -8
-- file unchanged
X.in +8
No savings is achieved by
compression.  The input remains virgin.
X.in -8
X.SH "BUGS"
Although compressed files are compatible between machines with large memory,
X.BR \-b \12
should be used for file transfer to architectures with 
a small process data space (64KB or less, as exhibited by the DEC PDP
series, the Intel 80286, etc.)
SHAR_EOF
if test 5147 -ne "`wc -c < 'compress.1'`"
then
	echo shar: error transmitting "'compress.1'" '(should have been 5147 characters)'
fi
fi # end of overwriting check
echo shar: extracting "'compress.c'" '(39614 characters)'
if test -f 'compress.c'
then
	echo shar: will not over-write existing file "'compress.c'"
else
sed 's/^X//' << \SHAR_EOF > 'compress.c'
/* 
 * 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!harpo!utah-cs!utah-gr!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>

#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 */
count_int htab [HSIZE];
unsigned short codetab [HSIZE];
#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;

code_int getcode();

Usage() {
#ifdef DEBUG
fprintf(stderr,"Usage: compress [-dDVfc] [-b maxbits] [file ...]\n");
}
int debug = 0;
#else
fprintf(stderr,"Usage: compress [-dfvcV] [-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 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 (*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();


    if ( (bgnd_flag = signal ( SIGINT, SIG_IGN )) != SIG_IGN ) {
	signal ( SIGINT, onintr );
	signal ( SIGSEGV, oops );
    }

#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 != 0) {			/* 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); 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); 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 (foreground()) {
			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);
		    continue;
		}
		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 */
		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(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;
    } 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;
    } 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);
}
/*
 * This routine returns 1 if we are running in the foreground and stderr
 * is a tty.
 */
foreground()
{
	if(bgnd_flag) {	/* background? */
		return(0);
	} else {			/* foreground */
		if(isatty(2)) {		/* and stderr is a tty */
			return(1);
		} else {
			return(0);
		}
	}
}

onintr ( )
{
    unlink ( ofname );
    exit ( 1 );
}

oops ( )	/* wild pointer -- assume bad input */
{
    if ( do_decomp == 1 ) 
    	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)
XFILE *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\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);
}
SHAR_EOF
if test 39614 -ne "`wc -c < 'compress.c'`"
then
	echo shar: error transmitting "'compress.c'" '(should have been 39614 characters)'
fi
fi # end of overwriting check
echo shar: extracting "'Makefile'" '(1435 characters)'
if test -f 'Makefile'
then
	echo shar: will not over-write existing file "'Makefile'"
else
sed 's/^X//' << \SHAR_EOF > 'Makefile'
CC=cc
COMFLAGS=-O
BIN=/usr/bin
MAN=/usr/man/man1
#define to "l" if manuals go on /usr/man/manl
L=1

all :	compress atob btoa

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.  See the README file for more info.
USERMEM:
	sh usermem > USERMEM

atob:	atob.c
	$(CC) $(COMFLAGS) -o atob atob.c

btoa:	btoa.c
	$(CC) $(COMFLAGS) -o btoa btoa.c

install: compress atob btoa zmore zcmp zdiff compressdir uncompressdir btoa.1 compress.1 compressdir.1 zmore.1 zcmp.1 tarmail untarmail
	cp compress $(BIN)
	rm -f $(BIN)/uncompress $(BIN)/zcat
	ln $(BIN)/compress $(BIN)/uncompress
	ln $(BIN)/compress $(BIN)/zcat
	cp zmore zcmp zdiff compressdir uncompressdir $(BIN)
	cp atob btoa tarmail untarmail $(BIN)
	cp btoa.1 $(MAN)/btoa.$(L)
	rm -f $(MAN)/atob.$(L) $(MAN)/tarmail.$(L) $(MAN)/untarmail.$(L)
	ln $(MAN)/btoa.$(L) $(MAN)/atob.$(L)
	ln $(MAN)/btoa.$(L) $(MAN)/tarmail.$(L)
	ln $(MAN)/btoa.$(L) $(MAN)/untarmail.$(L)
	cp compress.1 $(MAN)/compress.$(L)
	rm -f $(MAN)/uncompress.$(L) $(MAN)/zcat.$(L)
	ln $(MAN)/compress.$(L) $(MAN)/uncompress.$(L)
	ln $(MAN)/compress.$(L) $(MAN)/zcat.$(L)
	cp compressdir.1 $(MAN)/compressdir.$(L)
	cp zmore.1 $(MAN)/zmore.$(L)
	cp zcmp.1 $(MAN)/zcmp.$(L)
	rm -f $(MAN)/zdiff.$(L)
	ln $(MAN)/zcmp.$(L) $(MAN)/zdiff.$(L)

clean:
	rm -f compress atob btoa
SHAR_EOF
if test 1435 -ne "`wc -c < 'Makefile'`"
then
	echo shar: error transmitting "'Makefile'" '(should have been 1435 characters)'
fi
fi # end of overwriting check
echo shar: extracting "'usermem'" '(1748 characters)'
if test -f 'usermem'
then
	echo shar: will not over-write existing file "'usermem'"
else
sed 's/^X//' << \SHAR_EOF > 'usermem'
: 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 $*

XSIZE=0
if test -r /usr/adm/messages	# probably the most transportable
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
	    : 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
	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
SHAR_EOF
if test 1748 -ne "`wc -c < 'usermem'`"
then
	echo shar: error transmitting "'usermem'" '(should have been 1748 characters)'
fi
chmod +x 'usermem'
fi # end of overwriting check
#	End of shell archive
exit 0