allbery@ncoast.UUCP (06/05/87)
From: cwruecmp!sun!seismo!scubed!sdcsvax!ucsbcsl!nessus!paul (Paul Traina)
A couple of weeks ago, I posted a message asking if anyone knew why compress
would not work on my Microport (286) based machine (in large model mode).
As it turns out, the whole problem is that the authors assumed that if one
can handle the memory requirements for a 16-bit compress, one must
*obviously* have 32 bit long integers...
Sigh.
Anyway, here a copy of the code I received from one person. It seems that
there are many (very slightly different) versions of compress laying about,
so I don't feel good about sending out context diffs (sorry, but you might
end up thanking me..?).
I'd like to thank all of the people that responded to my posting. It turns
out that the problem was that a few variables needed to become longs...
nothing else (compiling in the huge memory model would not have worked and
is not supported by Microport (boo hiss! come on guys...)).
I asked for permission from the person that sent me this program if I might
post it to the net. I never heard back from him, and it seems that there
are a bunch of people dying for this... so I hope it's ok with you... ahem
---------------------------------------------------------------------------
/*
* Compress - data compression program
*/
#define min(a,b) ((a>b) ? b : a)
extern void exit(), perror();
extern char *strcpy(), *strcat();
/*
* 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)
*/
/* $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.
*
*/
#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 = 1L << BITS; /* should NEVER generate this code */
#ifdef COMPATIBLE /* But wrong! */
# define MAXCODE(n_bits) (1L << (n_bits) - 1)
#else
# define MAXCODE(n_bits) ((1L << (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(1L<<BITS))
#endif /* XENIX_16 */
code_int free_ent = 0; /* first unused entry */
int exit_stat = 0;
code_int getcode();
Usage() {
#ifdef DEBUG
(void)fprintf(stderr,"Usage: compress [-dDVfc] [-b maxbits] [file ...]\n");
}
int debug = 0;
#else
(void)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 ) {
(void)signal ( SIGINT, onintr );
(void)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()) {
(void)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:
(void)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 = 1L << 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 */
(void)strcpy(tempname, *fileptr);
(void)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))) {
(void)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 = 1L << maxbits;
if(maxbits > BITS) {
(void)fprintf(stderr,
"%s: compressed with %d bits, can only handle %d bits\n",
*fileptr, maxbits, BITS);
continue;
}
}
/* Generate output filename */
(void)strcpy(ofname, *fileptr);
ofname[strlen(*fileptr) - 2] = '\0'; /* Strip off .Z */
} else { /* COMPRESSION */
if (strcmp(*fileptr + strlen(*fileptr) - 2, ".Z") == 0) {
(void)fprintf(stderr, "%s: already has .Z suffix -- no change\n",
*fileptr);
continue;
}
/* Open input file */
if ((freopen(*fileptr, "r", stdin)) == NULL) {
perror(*fileptr); continue;
}
(void)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 < (1L << 12) )
hsize = min ( 5003L, HSIZE );
else if ( fsize < (1L << 13) )
hsize = min ( 9001L, HSIZE );
else if ( fsize < (1L << 14) )
hsize = min ( 18013L, HSIZE );
else if ( fsize < (1L << 15) )
hsize = min ( 35023L, HSIZE );
else if ( fsize < 47000L )
hsize = min ( 50021L, HSIZE );
/* Generate output filename */
(void)strcpy(ofname, *fileptr);
#ifndef BSD4_2 /* Short filenames */
if ((cp=rindex(ofname,'/')) != NULL) cp++;
else cp = ofname;
if (strlen(cp) > 12) {
(void)fprintf(stderr,"%s: filename too long to tack on .Z\n",cp);
continue;
}
#endif /* BSD4_2 Long filenames allowed */
(void)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';
(void)fprintf(stderr, "%s already exists;", ofname);
if (foreground()) {
(void)fprintf(stderr, " do you wish to overwrite %s (y or n)? ",
ofname);
(void)fflush(stderr);
(void)read(2, response, 2);
while (response[1] != '\n') {
if (read(2, response+1, 1) < 0) { /* Ack! */
perror("stderr"); break;
}
}
}
if (response[0] != 'y') {
(void)fprintf(stderr, "\tnot overwritten\n");
continue;
}
}
}
if(zcat_flg == 0) { /* Open output file */
if (freopen(ofname, "w", stdout) == NULL) {
perror(ofname);
continue;
}
if(!quiet)
(void)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))
(void)putc('\n', stderr);
}
}
} else { /* Standard input */
if (do_decomp == 0) {
compress();
#ifdef DEBUG
if(verbose) dump_tab();
#endif /* DEBUG */
if(!quiet)
(void)putc('\n', stderr);
} else {
/* Check the magic number */
if (nomagic == 0) {
if ((getchar()!=(magic_header[0] & 0xFF))
|| (getchar()!=(magic_header[1] & 0xFF))) {
(void)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 = 1L << maxbits;
fsize = 100000; /* assume stdin large for USERMEM */
if(maxbits > BITS) {
(void)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);
/*NOTREACHED*/
}
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) {
(void)putchar((char)magic_header[0]); (void)putchar((char)magic_header[1]);
(void)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 = (((long)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
(void)fprintf( stderr,
"%ld chars in, %ld codes (%ld bytes) out, compression factor: ",
in_count, out_count, bytes_out );
prratio( stderr, in_count, bytes_out );
(void)fprintf( stderr, "\n");
(void)fprintf( stderr, "\tCompression as in compact: " );
prratio( stderr, in_count-bytes_out, in_count );
(void)fprintf( stderr, "\n");
(void)fprintf( stderr, "\tLargest code (of last block) was %d (%d bits)\n",
free_ent - 1, n_bits );
#else /* !DEBUG */
(void)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 )
(void)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]) | ((long)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 == ((long)n_bits << 3) ) {
bp = buf;
bits = n_bits;
bytes_out += bits;
do
(void)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 ) {
(void)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 )
(void)fwrite( buf, 1, (offset + 7) / 8, stdout );
bytes_out += (offset + 7) / 8;
offset = 0;
(void)fflush( stdout );
#ifdef DEBUG
if ( verbose )
(void)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 */
(void)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
(void)putchar ((char) *--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;
}
(void)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 poffset = 0, size = 0;
static char_type pbuf[BITS];
register int r_off, bits;
register char_type *bp = pbuf;
if ( clear_flg > 0 || poffset >= 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 pbuffer 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((char *) pbuf, 1, n_bits, stdin );
if ( size <= 0 )
return -1; /* end of file */
poffset = 0;
/* Round size down to integral number of codes */
size = ((long)size << 3) - (n_bits - 1);
}
r_off = poffset;
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, poffset 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 */
poffset += 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 ) {
(void)fprintf(stderr, "\nChange to %d bits\n", n_bits );
bits = n_bits;
col = 0;
}
(void)fprintf(stderr, "%5d%c", code, (col+=6) >= 74 ? (col = 0, '\n') : ' ' );
}
(void)putc( '\n', stderr );
exit( 0 );
}
code_int sorttab[1L<<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++) {
(void)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);
(void)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) )
(void)fprintf( stderr, "%5d: %5d/'%c' \"",
ent, tab_prefixof(ent), c );
else
(void)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);
}
(void)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 );
(void)unlink ( ofname );
exit ( 1 );
}
copystat(ifname, pofname)
char *ifname, *pofname;
{
struct stat statbuf;
int mode;
struct utimbuf {
time_t actime, modtime;
};
struct utimbuf timep;
(void)fclose(stdout);
if (stat(ifname, &statbuf)) { /* Get stat on input file */
perror(ifname);
return;
}
if ((long)(statbuf.st_mode & S_IFMT) != (long)S_IFREG) {
if(quiet)
(void)fprintf(stderr, "%s: ", ifname);
(void)fprintf(stderr, " -- not a regular file: unchanged");
exit_stat = 1;
} else if (statbuf.st_nlink > 1) {
if(quiet)
(void)fprintf(stderr, "%s: ", ifname);
(void)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)
(void)fprintf(stderr, " -- file unchanged");
} else { /* ***** Successful Compression ***** */
exit_stat = 0;
mode = statbuf.st_mode & 07777;
if (chmod(pofname, mode)) /* Copy modes */
perror(pofname);
(void)chown(pofname, (int)statbuf.st_uid, (int)statbuf.st_gid); /* Copy ownership */
timep.actime = statbuf.st_atime;
timep.modtime = statbuf.st_mtime;
(void) utime (pofname, &timep); /* Update last accessed and modified times */
if (unlink(ifname)) /* Remove input file */
perror(ifname);
if(!quiet)
(void)fprintf(stderr, " -- replaced with %s", pofname);
return; /* Successful return */
}
/* Unsuccessful return -- one of the tests failed */
if (unlink(pofname))
perror(pofname);
}
/*
* 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 ( )
{
(void)unlink ( ofname );
exit ( 1 );
}
oops ( ) /* wild pointer -- assume bad input */
{
if ( do_decomp == 1 )
(void)fprintf ( stderr, "uncompress: corrupt input\n" );
(void)unlink ( ofname );
exit ( 1 );
}
cl_block () /* table clear for block compress */
{
register long int rat;
checkpoint = in_count + CHECK_GAP;
#ifdef DEBUG
if ( debug ) {
(void)fprintf ( stderr, "count: %ld, ratio: ", in_count );
prratio ( stderr, in_count, bytes_out );
(void)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)
(void)fprintf ( stderr, "clear\n" );
#endif /* DEBUG */
}
}
cl_hash(phsize) /* reset code table */
register count_int phsize;
{
#ifndef XENIX_16 /* Normal machine */
register count_int *htab_p = htab+phsize;
#else
register j;
register long k = phsize;
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 = phsize - 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) {
(void)putc('-', stream);
q = -q;
}
(void)fprintf(stream, "%d.%02d%%", q / 100, q % 100);
}
version()
{
(void)fprintf(stderr, "Options: ");
#ifdef vax
(void)fprintf(stderr, "vax, ");
#endif
#ifdef NO_UCHAR
(void)fprintf(stderr, "NO_UCHAR, ");
#endif
#ifdef SIGNED_COMPARE_SLOW
(void)fprintf(stderr, "SIGNED_COMPARE_SLOW, ");
#endif
#ifdef XENIX_16
(void)fprintf(stderr, "XENIX_16, ");
#endif
#ifdef COMPATIBLE
(void)fprintf(stderr, "COMPATIBLE, ");
#endif
#ifdef DEBUG
(void)fprintf(stderr, "DEBUG, ");
#endif
#ifdef BSD4_2
(void)fprintf(stderr, "BSD4_2, ");
#endif
(void)fprintf(stderr, "BITS = %d\n", BITS);
}
------------ end of compress.c -----------------------------------------
--
{ucbvax|sdcsvax|pyramid}!ucsbcsl!nessus!paul Paul S. Traina
paul%nessus%sbphy.ucsb@lbl.arpa VMS & UNIX Systems Programmer
paul%nessus@sbitp.bitnet [your company name can be here]
pst@ai.ai.mit.edu +1 805 968-1658 (Santa Barbara)
--
Brandon S. Allbery {decvax,cbatt,cbosgd}!cwruecmp!ncoast!allbery
Tridelta Industries {ames,mit-eddie,talcott}!necntc!ncoast!allbery
7350 Corporate Blvd. necntc!ncoast!allbery@harvard.HARVARD.EDU
Mentor, OH 44060 +01 216 255 1080 (also eddie.MIT.EDU)