compress.c

UNIX、Linux环境下

	writeerr();
}

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

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

    if ( clear_flg > 0 || offset >= size || free_ent > maxcode ) {
	/*
	 * If the next entry will be too big for the current code
	 * size, then we must increase the size.  This implies reading
	 * a new buffer full, too.
	 */
	if ( free_ent > maxcode ) {
	    n_bits++;
	    if ( n_bits == maxbits )
		maxcode = maxmaxcode;	/* won't get any bigger now */
	    else
		maxcode = MAXCODE(n_bits);
	}
	if ( clear_flg > 0) {
    	    maxcode = MAXCODE (n_bits = INIT_BITS);
	    clear_flg = 0;
	}
	size = fread( buf, 1, n_bits, stdin );
	if ( size <= 0 )
	    return -1;			/* end of file */
	offset = 0;
	/* Round size down to integral number of codes */
	size = (size << 3) - (n_bits - 1);
    }
    r_off = offset;
    bits = n_bits;
	/*
	 * 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 */

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

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

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

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

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

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

void
copystat(ifname, ofname)
char *ifname, *ofname;
{
    struct stat statbuf;
    mode_t mode;
    struct utimbuf timep;

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

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

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

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

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;
{
	register count_int *htab_p = htab+hsize;
	register long i;
	register 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 int num, den;
{
	register int q;			/* Doesn't need to be long */

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

/* do_Pflag                                                             */
/*      Read file names from the pipe and compress/decompress them   	*/
/*    	overwriting the original file. 					*/
/*      Note: <stdio.h> defined BUFSIZ chunks are read from the pipe.   */
/*      Programs using the -P option should write in BUFSIZ chunks.  	*/

void
do_Pflag() {
    	char namebuf[BUFSIZ];   /* Buffer for fnames passed through pipe.  */
    	struct utimbuf timep;
	char lng_ctmp[100], *dirname();
    	struct stat statbuf;

	/* A NULL, EOF or broken pipe will break loop. 	*/
    	while (read(rpipe, namebuf, sizeof(namebuf)) > 0) { 
	    if(namebuf[0] == '\0') break;
	    /* Open input file */
	    if ((freopen(namebuf, "r", stdin)) == NULL) {
	        perror(namebuf);
	        continue;
	    }
	    if (stat( namebuf, &statbuf ) < 0) {
		perror(namebuf);
		continue;
	    }

	    if (do_decomp) {  /* DECOMPRESSION */
		/* Check the magic number */
		if (nomagic == 0) {
		    if ((getchar() != (magic_header[0] & 0xFF))
		     || (getchar() != (magic_header[1] & 0xFF))) {
			/* File not in compressed format. No problem. */
		    	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",
		       namebuf, maxbits, BITS);
		       continue;
		    }
		}
	    } 
	    else {  /* COMPRESSION */
		fsize = (long) statbuf.st_size;
		/*
		 * tune hash table size for small files -- as below 
		 */
		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 );
	   }
	   /* Add full path to ctmp. */
	   sprintf(lng_ctmp, "%s%s", dirname(namebuf), ctmp);
	   /* Set output filename to ctmp. */
	   if (freopen(lng_ctmp, "w", stdout) == NULL) {
	       perror(ctmp);
	       continue;
	   }
	   /* Do actual compress/decompress. */
	   if (do_decomp) 
		decompress(); 
	   else
		compress();
   
	   fflush(stdout);
	   /* Remove input file. */
	   if (unlink(namebuf))		
		perror(namebuf);	
	   /* Link tmp file to input filename. */
	   if( (link(lng_ctmp, namebuf)) < 0) {   
		perror(namebuf);
		fprintf(stderr, "Compress: Cannot link tmp to %s\n",namebuf);
	   }
	   /* Always unlink tmp file. */
	   unlink(lng_ctmp);	

	   /* Set time, mode and ownership for new file. */
	   timep.actime = time((long *) 0);
	   timep.modtime = statbuf.st_mtime;
	   utime(namebuf, &timep);
	   chmod(namebuf, statbuf.st_mode);
	   chown(namebuf, statbuf.st_uid, statbuf.st_gid);
	}
	/* Make sure tmp is gone. */
	unlink(lng_ctmp);			
	exit(0);
}


/* dirname					*/
/*      Return the directory portion of lname.	*/
/*						*/
char *
dirname(lname)
char *lname;
{
	char *cp, *end;
	static char buf[100];

	if (lname[0] == '/' || lname[1] == '/') 
		strcpy(buf, lname);
	else {
		strcpy(buf, "./");
		strcat(buf, lname);
	}
	end = &buf[strlen(buf)];
	for(cp = end; *cp != '/'; cp--); 
	*(cp+1)='\0';
	return(buf);
}

void
version()
{
	fprintf(stderr, "%s, Berkeley 5.9 5/11/86\n", rcs_ident);
	fprintf(stderr, "Options: ");
#ifdef DEBUG
	fprintf(stderr, "DEBUG, ");
#endif
	fprintf(stderr, "BITS = %d\n", BITS);
}