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minix/commands/compress/compress.c

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Initial revision
2005-04-21 16:53:53 +02:00
/* compress - Reduce file size using Modified Lempel-Ziv encoding */
/*
* 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)
*
* Richard Todd Port to MINIX
* Andy Tanenbaum Cleanup
*
*
* 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.
*
* -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.
*/
#define AZTEC86 1
#define min(a,b) ((a>b) ? b : a)
/*
* 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
#define REGISTER register
#define DOTZ ".Z"
#include <limits.h>
Nit in compress about filenames; backup patched to use opendir() and readdir() (old dir format didn't work)
2005-07-18 11:33:27 +02:00
#include <dirent.h>
Initial revision
2005-04-21 16:53:53 +02:00
/* The default for Minix is -b13, but we can do -b16 if the machine can. */
#define DEFAULTBITS 13
#if INT_MAX == 32767
# define BITS 13
#else
# define BITS 16
#endif
#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
#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
/*
* 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 */
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <ctype.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <utime.h>
#include <stdio.h>
#define ARGVAL() (*++(*argv) || (--argc && *++argv))
int n_bits; /* number of bits/code */
int maxbits = DEFAULTBITS; /* 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 */
#ifndef AZTEC86
count_int htab [HSIZE];
unsigned short codetab [HSIZE];
#else
count_int *htab;
unsigned short *codetab;
# define HTABSIZE ((size_t)(HSIZE*sizeof(count_int)))
# define CODETABSIZE ((size_t)(HSIZE*sizeof(unsigned short)))
#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;
_PROTOTYPE(int main, (int argc, char **argv));
_PROTOTYPE(void Usage, (void));
_PROTOTYPE(void compress, (void));
_PROTOTYPE(void onintr, (int dummy));
_PROTOTYPE(void oops, (int dummy));
_PROTOTYPE(void output, (code_int code));
_PROTOTYPE(int foreground, (void));
_PROTOTYPE(void decompress, (void));
_PROTOTYPE(code_int getcode, (void));
_PROTOTYPE(void writeerr, (void));
_PROTOTYPE(void copystat, (char *ifname, char *ofname));
_PROTOTYPE(int foreground, (void));
_PROTOTYPE(void cl_block , (void));
_PROTOTYPE(void cl_hash, (count_int hsize));
_PROTOTYPE(void prratio, (FILE *stream, long int num, long int den));
_PROTOTYPE(void version, (void));
void 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 = 0; /* 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 */
#ifndef METAWARE
#ifdef AZTEC86
void
#else
int
#endif
#ifndef __STDC__
(*bgnd_flag)();
#else
(*bgnd_flag)(int);
#endif
#endif
int do_decomp = 0;
int main(argc, argv)
int argc;
char **argv;
{
int overwrite = 0; /* Do not overwrite unless given -f flag */
char tempname[100];
char **filelist, **fileptr;
char *cp;
struct stat statbuf;
#ifndef METAWARE
if ( (bgnd_flag = signal ( SIGINT, SIG_IGN )) != SIG_IGN ) {
signal ( SIGINT, onintr );
signal ( SIGSEGV, oops );
}
#endif
#ifdef AZTEC86
#ifdef METAWARE
_setmode(NULL,_ALL_FILES_BINARY);
_setmode(stdin,_BINARY);
_setmode(stdout,_BINARY);
_setmode(stderr,_TEXT);
#endif
if (NULL == (htab = (count_int *)malloc(HTABSIZE)))
{
fprintf(stderr,"Can't allocate htab\n");
exit(1);
}
if (NULL == (codetab = (unsigned short *)malloc(CODETABSIZE)))
{
fprintf(stderr,"Can't allocate codetab\n");
exit(1);
}
#endif
#ifdef COMPATIBLE
nomagic = 1; /* Original didn't have a magic number */
#endif /* COMPATIBLE */
filelist = fileptr = (char **)(malloc((size_t)(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;
}
#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 */
#ifndef PCDOS
if (strcmp(*fileptr + strlen(*fileptr) - 2, DOTZ) != 0)
#else
if (strcmp(*fileptr + strlen(*fileptr) - 1, DOTZ) != 0)
#endif
{
/* No .Z: tack one on */
strcpy(tempname, *fileptr);
#ifndef PCDOS
strcat(tempname, DOTZ);
#else
/* either tack one on or replace last character */
{
char *dot;
if (NULL == (dot = strchr(tempname,'.')))
{
strcat(tempname,".Z");
}
else
/* if there is a dot then either tack a z on
or replace last character */
{
if (strlen(dot) < 4)
strcat(tempname,DOTZ);
else
dot[3] = 'Z';
}
}
#endif
*fileptr = tempname;
}
/* Open input file */
if ((freopen(*fileptr, "r", stdin)) == NULL)
{
perror(*fileptr); continue;
}
/* Check the magic number */
if (nomagic == 0)
{
unsigned magic1, magic2;
if (((magic1 = getc(stdin)) != (magic_header[0] & 0xFF))
|| ((magic2 = getc(stdin)) != (magic_header[1] & 0xFF)))
{
fprintf(stderr,
"%s: not in compressed format %x %x\n",
*fileptr,magic1,magic2);
continue;
}
maxbits = getc(stdin); /* 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);
#ifndef PCDOS
ofname[strlen(*fileptr) - 2] = '\0'; /* Strip off .Z */
#else
/* kludge to handle various common three character extension */
{
char *dot;
char fixup = '\0';
/* first off, map name to upper case */
for (dot = ofname; *dot; dot++)
*dot = toupper(*dot);
if (NULL == (dot = strchr(ofname,'.')))
{
fprintf(stderr,"Bad filename %s\n",ofname);
exit(1);
}
if (strlen(dot) == 4)
/* we got three letter extensions */
{
if (strcmp(dot,".EXZ") == 0)
fixup = 'E';
else if (strcmp(dot,".COZ") == 0)
fixup = 'M';
else if (strcmp(dot,".BAZ") == 0)
fixup = 'S';
else if (strcmp(dot,".OBZ") == 0)
fixup = 'J';
else if (strcmp(dot,".SYZ") == 0)
fixup = 'S';
else if (strcmp(dot,".DOZ") == 0)
fixup = 'C';
}
/* replace the Z */
ofname[strlen(*fileptr) - 1] = fixup;
}
#endif
} else
{ /* COMPRESSION */
if (strcmp(*fileptr + strlen(*fileptr) - 2, DOTZ) == 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; /*lint -e506 -e712 */
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 ); /*lint +e506 +e712 */
/* Generate output filename */
strcpy(ofname, *fileptr);
#ifndef BSD4_2 /* Short filenames */
if ((cp=strrchr(ofname,'/')) != NULL)
cp++;
else
cp = ofname;
Nit in compress about filenames; backup patched to use opendir() and readdir() (old dir format didn't work)
2005-07-18 11:33:27 +02:00
if (strlen(cp) >= _DIRENT_NAME_LEN-3)
Initial revision
2005-04-21 16:53:53 +02:00
{
fprintf(stderr,"%s: filename too long to tack on .Z\n",cp);
continue;
}
#ifdef PCDOS
else
{
/* either tack one on or replace last character */
char *dot;
if (NULL == (dot = strchr(cp,'.')))
{
strcat(cp,".Z");
}
else
/* if there is a dot then either tack a z on
or replace last character */
{
if (strlen(dot) < 4)
strcat(cp,DOTZ);
else
dot[3] = 'Z';
}
}
#endif
#endif /* BSD4_2 Long filenames allowed */
#ifndef PCDOS
/* PCDOS takes care of this above */
strcat(ofname, DOTZ);
#endif
}
/* Check for overwrite of existing file */
if (overwrite == 0 && zcat_flg == 0)
{
if (stat(ofname, &statbuf) == 0)
{
char response[2]; int fd;
response[0] = 'n';
fprintf(stderr, "%s already exists;", ofname);
if (foreground())
{
fd = open("/dev/tty", O_RDONLY);
fprintf(stderr,
" do you wish to overwrite %s (y or n)? ", ofname);
fflush(stderr);
(void)read(fd, response, 2);
while (response[1] != '\n')
{
if (read(fd, response+1, 1) < 0)
{ /* Ack! */
perror("stderr");
break;
}
}
close(fd);
}
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 ((getc(stdin)!=(magic_header[0] & 0xFF))
|| (getc(stdin)!=(magic_header[1] & 0xFF)))
{
fprintf(stderr, "stdin: not in compressed format\n");
exit(1);
}
maxbits = getc(stdin); /* 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 */
}
}
return(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.
*/
void 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)
{
putc(magic_header[0],stdout);
putc(magic_header[1],stdout);
putc((char)(maxbits | block_compress),stdout);
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 = getc(stdin);
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 = getc(stdin)) != (unsigned) EOF )
#else
while ( (c = getc(stdin)) != 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 */
void 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;
#ifndef BREAKHIGHC
#ifdef METAWARE
int temp;
#endif
#endif
#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.
*/
#ifndef BREAKHIGHC
#ifdef METAWARE
*bp &= rmask[r_off];
temp = (code << r_off) & lmask[r_off];
*bp |= temp;
#else
*bp = (*bp & rmask[r_off]) | ((code << r_off) & lmask[r_off]);
#endif
#else
*bp = (*bp & rmask[r_off]) | ((code << r_off) & lmask[r_off]);
#endif
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
putc(*bp++,stdout);
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, (size_t)1, (size_t)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, (size_t)1, (size_t)(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.
*/
void 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 */
putc( (char)finchar,stdout ); /* 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
putc ( *--stackp ,stdout);
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, (size_t)1, (size_t)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;
}
#ifndef AZTEC86
char *
strrchr(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);
}
#endif
#ifndef METAWARE
#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 );
}
#ifdef DEBUG2
code_int sorttab[1<<BITS]; /* sorted pointers into htab */
#define STACK_SIZE 500
static char stack[STACK_SIZE];
/* dumptab doesn't use main stack now -prevents distressing crashes */
dump_tab() /* dump string table */
{
REGISTER int i, first;
REGISTER ent;
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);
stack[--stack_top] = '\n';
stack[--stack_top] = '"'; /* " */
stack_top = in_stack((int)(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((int)(htabof(sorttab[ent]) >> maxbits),
stack_top);
}
stack_top = in_stack(ent, stack_top);
fwrite( &stack[stack_top], (size_t)1, (size_t)(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 );
stack[--stack_top] = '\n';
stack[--stack_top] = '"'; /* " */
for ( ; ent != NULL;
ent = (ent >= FIRST ? tab_prefixof(ent) : NULL) ) {
stack_top = in_stack(tab_suffixof(ent), stack_top);
}
fwrite( &stack[stack_top], (size_t)1, (size_t)(STACK_SIZE - stack_top), stderr );
stack_top = STACK_SIZE;
}
}
}
int
in_stack(c, stack_top)
REGISTER int c, stack_top;
{
if ( (isascii(c) && isprint(c) && c != '\\') || c == ' ' ) {
stack[--stack_top] = c;
} else {
switch( c ) {
case '\n': stack[--stack_top] = 'n'; break;
case '\t': stack[--stack_top] = 't'; break;
case '\b': stack[--stack_top] = 'b'; break;
case '\f': stack[--stack_top] = 'f'; break;
case '\r': stack[--stack_top] = 'r'; break;
case '\\': stack[--stack_top] = '\\'; break;
default:
stack[--stack_top] = '0' + c % 8;
stack[--stack_top] = '0' + (c / 8) % 8;
stack[--stack_top] = '0' + c / 64;
break;
}
stack[--stack_top] = '\\';
}
if (stack_top<0) {
fprintf(stderr,"dump_tab stack overflow!!!\n");
exit(1);
}
return stack_top;
}
#else
dump_tab() {}
#endif /* DEBUG2 */
#endif /* DEBUG */
#endif /* METAWARE */
void writeerr()
{
perror ( ofname );
unlink ( ofname );
exit ( 1 );
}
void copystat(ifname, ofname)
char *ifname, *ofname;
{
struct stat statbuf;
int mode;
#ifndef AZTEC86
time_t timep[2];
#else
unsigned long timep[2];
#endif
fflush(stdout);
close(fileno(stdout));
if (stat(ifname, &statbuf))
{ /* Get stat on input file */
perror(ifname);
return;
}
#ifndef PCDOS
/* meddling with UNIX-style file modes */
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
#endif
if (exit_stat == 2 && (!force))
{ /* No compression: remove file.Z */
if(!quiet)
fprintf(stderr, " -- file unchanged");
} else
{ /* ***** Successful Compression ***** */
exit_stat = 0;
#ifndef PCDOS
mode = statbuf.st_mode & 07777;
#else
mode = statbuf.st_attr & 07777;
#endif
if (chmod(ofname, mode)) /* Copy modes */
perror(ofname);
#ifndef PCDOS
chown(ofname, statbuf.st_uid, statbuf.st_gid); /* Copy ownership */
timep[0] = statbuf.st_atime;
timep[1] = statbuf.st_mtime;
#else
timep[0] = statbuf.st_mtime;
timep[1] = statbuf.st_mtime;
#endif
utime(ofname, (struct utimbuf *)timep); /* Update last accessed and modified times */
/*
if (unlink(ifname))
perror(ifname);
*/
if(!quiet)
if(do_decomp == 0)
fprintf(stderr, " -- compressed to %s", ofname);
else
fprintf(stderr, " -- decompressed to %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.
*/
int foreground()
{
#ifndef METAWARE
if(bgnd_flag) { /* background? */
return(0);
} else { /* foreground */
#endif
if(isatty(2)) { /* and stderr is a tty */
return(1);
} else {
return(0);
}
#ifndef METAWARE
}
#endif
}
#ifndef METAWARE
void onintr (dummy)
int dummy; /* to keep the compiler happy */
{
(void)signal(SIGINT,SIG_IGN);
unlink ( ofname );
exit ( 1 );
}
void oops (dummy) /* wild pointer -- assume bad input */
int dummy; /* to keep the compiler happy */
{
(void)signal(SIGSEGV,SIG_IGN);
if ( do_decomp == 1 )
fprintf ( stderr, "uncompress: corrupt input\n" );
unlink ( ofname );
exit ( 1 );
}
#endif
void 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 */
}
}
void cl_hash(hsize) /* reset code table */
REGISTER count_int hsize;
{
#ifdef AZTEC86
#ifdef PCDOS
/* This function only in PC-DOS lib, not in MINIX lib */
memset(htab,-1, hsize * sizeof(count_int));
#else
/* MINIX and all non-PC machines do it this way */
#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;
#endif
#endif
}
void prratio(stream, num, den)
FILE *stream;
long int num;
long int den;
{
REGISTER int q; /* Doesn't need to be long */
if(num > 214748L)
{ /* 2147483647/10000 */
q = (int)(num / (den / 10000L));
} else
{
q = (int)(10000L * num / den); /* Long calculations, though */
}
if (q < 0)
{
putc('-', stream);
q = -q;
}
fprintf(stream, "%d.%02d%c", q / 100, q % 100, '%');
}
void version()
{
fprintf(stderr, "compress 4.1\n");
fprintf(stderr, "Options: ");
#ifdef vax
fprintf(stderr, "vax, ");
#endif
#ifdef _MINIX
fprintf(stderr, "MINIX, ");
#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);
}
/* End of text from uok.UUCP:net.sources */
Reference in a new issue Copy permalink