1275 lines
32 KiB
C
Executable File
1275 lines
32 KiB
C
Executable File
/*
|
|
* compress - File compression ala IEEE Computer, June 1984.
|
|
*
|
|
* 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:
|
|
* -b: limit the max number of bits/code.
|
|
* -c: write output on stdout, don't remove original.
|
|
* -d: decompress instead.
|
|
* -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.
|
|
|
|
* 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)
|
|
*/
|
|
|
|
#ifndef USED
|
|
# define USED(x) if(x);else
|
|
#endif
|
|
|
|
#define _PLAN9_SOURCE
|
|
#define _BSD_EXTENSION
|
|
#define _POSIX_SOURCE
|
|
|
|
#include <u.h>
|
|
#include <stdio.h>
|
|
#include <ctype.h>
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <string.h>
|
|
#include <signal.h>
|
|
#include <utime.h>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
|
|
#define min(a,b) ((a>b) ? b : a)
|
|
|
|
#define BITS 16
|
|
#define HSIZE 69001 /* 95% occupancy */
|
|
|
|
/*
|
|
* a code_int must be able to hold 2**BITS values of type int, and also -1
|
|
*/
|
|
typedef long code_int;
|
|
typedef long count_int;
|
|
|
|
static char rcs_ident[] = "$Header: compress.c,v 4.0 85/07/30 12:50:00 joe Release $";
|
|
|
|
uchar magic_header[] = { 0x1F, 0x9D }; /* 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 */
|
|
|
|
#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 */
|
|
|
|
#define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
|
|
|
|
count_int htab[HSIZE];
|
|
ushort codetab[HSIZE];
|
|
|
|
#define htabof(i) htab[i]
|
|
#define codetabof(i) codetab[i]
|
|
|
|
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)
|
|
#define tab_suffixof(i) ((uchar *)(htab))[i]
|
|
#define de_stack ((uchar *)&tab_suffixof(1<<BITS))
|
|
|
|
code_int free_ent = 0; /* first unused entry */
|
|
int exit_stat = 0;
|
|
|
|
void cl_block(void);
|
|
void cl_hash(count_int);
|
|
void compress(void);
|
|
void copystat(char *, char *);
|
|
void decompress(void);
|
|
int foreground(void);
|
|
code_int getcode(void);
|
|
void onintr(int);
|
|
void oops(int);
|
|
void output(code_int);
|
|
void prratio(FILE *, long, long);
|
|
void version(void);
|
|
void writeerr(void);
|
|
|
|
void
|
|
Usage(void)
|
|
{
|
|
#ifdef DEBUG
|
|
fprintf(stderr,"Usage: compress [-cdfDV] [-b maxbits] [file ...]\n");
|
|
#else
|
|
fprintf(stderr,"Usage: compress [-cdfvV] [-b maxbits] [file ...]\n");
|
|
#endif /* DEBUG */
|
|
}
|
|
|
|
int debug = 0;
|
|
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 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 */
|
|
void (*bgnd_flag)(int);
|
|
|
|
int do_decomp = 0;
|
|
|
|
int
|
|
main(argc, argv)
|
|
int argc;
|
|
char **argv;
|
|
{
|
|
int overwrite = 0; /* Do not overwrite unless given -f flag */
|
|
char tempname[512];
|
|
char **filelist, **fileptr;
|
|
char *cp;
|
|
struct stat statbuf;
|
|
|
|
if ( (bgnd_flag = signal ( SIGINT, SIG_IGN )) != SIG_IGN ) {
|
|
signal(SIGINT, onintr);
|
|
signal(SIGSEGV, oops);
|
|
}
|
|
|
|
filelist = fileptr = (char **)(malloc(argc * sizeof(*argv)));
|
|
*filelist = NULL;
|
|
|
|
if((cp = strrchr(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;
|
|
}
|
|
|
|
/*
|
|
* Argument Processing
|
|
* All flags are optional.
|
|
* -C generate output compatible with compress 2.0.
|
|
* -D debug
|
|
* -V print Version; debug verbose
|
|
* -b maxbits maxbits. If -b is specified, then maxbits MUST be
|
|
* given also.
|
|
* -c cat all output to stdout
|
|
* -d do_decomp
|
|
* -f force overwrite of output file
|
|
* -n no header: useful to uncompress old files
|
|
* -v unquiet
|
|
* 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) {
|
|
case 'C':
|
|
block_compress = 0;
|
|
break;
|
|
#ifdef DEBUG
|
|
case 'D':
|
|
debug = 1;
|
|
break;
|
|
case 'V':
|
|
verbose = 1;
|
|
version();
|
|
break;
|
|
#else
|
|
case 'V':
|
|
version();
|
|
break;
|
|
#endif
|
|
case 'b':
|
|
if (!ARGVAL()) {
|
|
fprintf(stderr, "Missing maxbits\n");
|
|
Usage();
|
|
exit(1);
|
|
}
|
|
maxbits = atoi(*argv);
|
|
goto nextarg;
|
|
case 'c':
|
|
zcat_flg = 1;
|
|
break;
|
|
case 'd':
|
|
do_decomp = 1;
|
|
break;
|
|
case 'f':
|
|
case 'F':
|
|
overwrite = 1;
|
|
force = 1;
|
|
break;
|
|
case 'n':
|
|
nomagic = 1;
|
|
break;
|
|
case 'q':
|
|
quiet = 1;
|
|
break;
|
|
case 'v':
|
|
quiet = 0;
|
|
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;
|
|
}
|
|
(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 < (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
|
|
if ((cp=strrchr(ofname,'/')) != NULL)
|
|
cp++;
|
|
else
|
|
cp = ofname;
|
|
/*
|
|
*** changed 12 to 25; should be NAMELEN-3, but I don't want
|
|
* to fight the headers. ehg 5 Nov 92 **
|
|
*/
|
|
if (strlen(cp) > 25) {
|
|
fprintf(stderr, "%s: filename too long to tack on .Z\n",
|
|
cp);
|
|
continue;
|
|
}
|
|
#endif
|
|
strcat(ofname, ".Z");
|
|
}
|
|
/* Check for overwrite of existing file */
|
|
if (overwrite == 0 && zcat_flg == 0 &&
|
|
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);
|
|
(void) 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
|
|
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);
|
|
return 0;
|
|
}
|
|
|
|
static int offset;
|
|
long in_count = 1; /* length of input */
|
|
long bytes_out; /* length of compressed output */
|
|
long 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.
|
|
*/
|
|
void
|
|
compress(void)
|
|
{
|
|
code_int ent, hsize_reg;
|
|
code_int i;
|
|
int c, disp, hshift;
|
|
long fcode;
|
|
|
|
if (nomagic == 0) {
|
|
putchar(magic_header[0]);
|
|
putchar(magic_header[1]);
|
|
putchar((char)(maxbits | block_compress));
|
|
if(ferror(stdout))
|
|
writeerr();
|
|
}
|
|
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 *= 2)
|
|
hshift++;
|
|
hshift = 8 - hshift; /* set hash code range bound */
|
|
|
|
hsize_reg = hsize;
|
|
cl_hash( (count_int) hsize_reg); /* clear hash table */
|
|
|
|
while ((c = getchar()) != EOF) {
|
|
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;
|
|
if (free_ent < maxmaxcode) {
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* 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). When the buffer fills up empty it and start over.
|
|
*/
|
|
|
|
static char buf[BITS];
|
|
|
|
uchar lmask[9] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
|
|
uchar rmask[9] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
|
|
|
|
void
|
|
output( code )
|
|
code_int code;
|
|
{
|
|
#ifdef DEBUG
|
|
static int col = 0;
|
|
#endif
|
|
int r_off = offset, bits= n_bits;
|
|
char *bp = buf;
|
|
|
|
#ifdef DEBUG
|
|
if (verbose)
|
|
fprintf(stderr, "%5d%c", code,
|
|
(col+=6) >= 74? (col = 0, '\n'): ' ');
|
|
#endif
|
|
if (code >= 0) {
|
|
/*
|
|
* 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;
|
|
|
|
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
|
|
}
|
|
} 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
|
|
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.
|
|
*/
|
|
void
|
|
decompress(void)
|
|
{
|
|
int finchar;
|
|
code_int code, oldcode, incode;
|
|
uchar *stackp;
|
|
|
|
/*
|
|
* 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) = (uchar)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
|
|
*/
|
|
while (code >= 256) {
|
|
*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) = (ushort)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()
|
|
{
|
|
int r_off, bits;
|
|
code_int code;
|
|
static int offset = 0, size = 0;
|
|
static uchar buf[BITS];
|
|
uchar *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;
|
|
/*
|
|
* Get to the first byte.
|
|
*/
|
|
bp += (r_off >> 3);
|
|
r_off &= 7;
|
|
/* Get first part (low order bits) */
|
|
code = (*bp++ >> r_off);
|
|
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) {
|
|
code |= *bp++ << r_off;
|
|
r_off += 8;
|
|
bits -= 8;
|
|
}
|
|
/* high order bits. */
|
|
code |= (*bp & rmask[bits]) << r_off;
|
|
offset += n_bits;
|
|
return code;
|
|
}
|
|
|
|
#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 */
|
|
|
|
#define STACK_SIZE 15000
|
|
|
|
dump_tab() /* dump string table */
|
|
{
|
|
int i, first, c, ent;
|
|
int stack_top = STACK_SIZE;
|
|
|
|
if(do_decomp == 0) { /* compressing */
|
|
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(int c, int 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 */
|
|
|
|
void
|
|
writeerr(void)
|
|
{
|
|
perror(ofname);
|
|
unlink(ofname);
|
|
exit(1);
|
|
}
|
|
|
|
void
|
|
copystat(ifname, ofname)
|
|
char *ifname, *ofname;
|
|
{
|
|
int mode;
|
|
time_t timep[2]; /* should be struct utimbuf */
|
|
struct stat statbuf;
|
|
|
|
fclose(stdout);
|
|
if (stat(ifname, &statbuf)) { /* Get stat on input file */
|
|
perror(ifname);
|
|
return;
|
|
}
|
|
if (!S_ISREG(statbuf.st_mode)) {
|
|
if (quiet)
|
|
fprintf(stderr, "%s: ", ifname);
|
|
fprintf(stderr, " -- not a regular file: unchanged");
|
|
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 & 0777;
|
|
if (chmod(ofname, mode)) /* Copy modes */
|
|
perror(ofname);
|
|
/* Copy ownership */
|
|
chown(ofname, statbuf.st_uid, statbuf.st_gid);
|
|
timep[0] = statbuf.st_atime;
|
|
timep[1] = statbuf.st_mtime;
|
|
/* Update last accessed and modified times */
|
|
utime(ofname, (struct utimbuf *)timep);
|
|
// if (unlink(ifname)) /* Remove input file */
|
|
// perror(ifname);
|
|
return; /* success */
|
|
}
|
|
|
|
/* 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.
|
|
*/
|
|
int
|
|
foreground(void)
|
|
{
|
|
if(bgnd_flag) /* background? */
|
|
return 0;
|
|
else /* foreground */
|
|
return isatty(2); /* and stderr is a tty */
|
|
}
|
|
|
|
void
|
|
onintr(int x)
|
|
{
|
|
USED(x);
|
|
unlink(ofname);
|
|
exit(1);
|
|
}
|
|
|
|
void
|
|
oops(int x) /* wild pointer -- assume bad input */
|
|
{
|
|
USED(x);
|
|
if (do_decomp == 1)
|
|
fprintf(stderr, "uncompress: corrupt input\n");
|
|
unlink(ofname);
|
|
exit(1);
|
|
}
|
|
|
|
void
|
|
cl_block(void) /* table clear for block compress */
|
|
{
|
|
long 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 */
|
|
}
|
|
}
|
|
|
|
void
|
|
cl_hash(count_int hsize) /* reset code table */
|
|
{
|
|
count_int *htab_p = htab+hsize;
|
|
long i;
|
|
long m1 = -1;
|
|
|
|
i = hsize - 16;
|
|
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);
|
|
for ( i += 16; i > 0; i-- )
|
|
*--htab_p = m1;
|
|
}
|
|
|
|
void
|
|
prratio(stream, num, den)
|
|
FILE *stream;
|
|
long num, den;
|
|
{
|
|
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);
|
|
}
|
|
|
|
void
|
|
version(void)
|
|
{
|
|
fprintf(stderr, "%s\n", rcs_ident);
|
|
fprintf(stderr, "Options: ");
|
|
#ifdef DEBUG
|
|
fprintf(stderr, "DEBUG, ");
|
|
#endif
|
|
#ifdef BSD4_2
|
|
fprintf(stderr, "BSD4_2, ");
|
|
#endif
|
|
fprintf(stderr, "BITS = %d\n", BITS);
|
|
}
|
|
|
|
/*
|
|
* The revision-history novel:
|
|
*
|
|
* $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.
|
|
*/
|