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Annotation of researchv9/cmd/compress/compress.c, revision 1.1

1.1     ! root        1: /* 
        !             2:  * Compress - data compression program 
        !             3:  */
        !             4: #define        min(a,b)        ((a>b) ? b : a)
        !             5: 
        !             6: /*
        !             7:  * machine variants which require cc -Dmachine:  pdp11, z8000, pcxt
        !             8:  */
        !             9: 
        !            10: /*
        !            11:  * Set USERMEM to the maximum amount of physical user memory available
        !            12:  * in bytes.  USERMEM is used to determine the maximum BITS that can be used
        !            13:  * for compression.
        !            14:  *
        !            15:  * SACREDMEM is the amount of physical memory saved for others; compress
        !            16:  * will hog the rest.
        !            17:  */
        !            18: #ifndef SACREDMEM
        !            19: #define SACREDMEM      0
        !            20: #endif
        !            21: 
        !            22: #ifndef USERMEM
        !            23: # define USERMEM       450000  /* default user memory */
        !            24: #endif
        !            25: 
        !            26: #ifdef interdata               /* (Perkin-Elmer) */
        !            27: #define SIGNED_COMPARE_SLOW    /* signed compare is slower than unsigned */
        !            28: #endif
        !            29: 
        !            30: #ifdef pdp11
        !            31: # define BITS  12      /* max bits/code for 16-bit machine */
        !            32: # define NO_UCHAR      /* also if "unsigned char" functions as signed char */
        !            33: # undef USERMEM 
        !            34: #endif /* pdp11 */     /* don't forget to compile with -i */
        !            35: 
        !            36: #ifdef z8000
        !            37: # define BITS  12
        !            38: # undef vax            /* weird preprocessor */
        !            39: # undef USERMEM 
        !            40: #endif /* z8000 */
        !            41: 
        !            42: #ifdef pcxt
        !            43: # define BITS   12
        !            44: # undef USERMEM
        !            45: #endif /* pcxt */
        !            46: 
        !            47: #ifdef USERMEM
        !            48: # if USERMEM >= (433484+SACREDMEM)
        !            49: #  define PBITS        16
        !            50: # else
        !            51: #  if USERMEM >= (229600+SACREDMEM)
        !            52: #   define PBITS       15
        !            53: #  else
        !            54: #   if USERMEM >= (127536+SACREDMEM)
        !            55: #    define PBITS      14
        !            56: #   else
        !            57: #    if USERMEM >= (73464+SACREDMEM)
        !            58: #     define PBITS     13
        !            59: #    else
        !            60: #     define PBITS     12
        !            61: #    endif
        !            62: #   endif
        !            63: #  endif
        !            64: # endif
        !            65: # undef USERMEM
        !            66: #endif /* USERMEM */
        !            67: 
        !            68: #ifdef PBITS           /* Preferred BITS for this memory size */
        !            69: # ifndef BITS
        !            70: #  define BITS PBITS
        !            71: # endif BITS
        !            72: #endif /* PBITS */
        !            73: 
        !            74: #if BITS == 16
        !            75: # define HSIZE 69001           /* 95% occupancy */
        !            76: #endif
        !            77: #if BITS == 15
        !            78: # define HSIZE 35023           /* 94% occupancy */
        !            79: #endif
        !            80: #if BITS == 14
        !            81: # define HSIZE 18013           /* 91% occupancy */
        !            82: #endif
        !            83: #if BITS == 13
        !            84: # define HSIZE 9001            /* 91% occupancy */
        !            85: #endif
        !            86: #if BITS <= 12
        !            87: # define HSIZE 5003            /* 80% occupancy */
        !            88: #endif
        !            89: 
        !            90: #ifdef M_XENIX                 /* Stupid compiler can't handle arrays with */
        !            91: # if BITS == 16                        /* more than 65535 bytes - so we fake it */
        !            92: #  define XENIX_16
        !            93: # else
        !            94: #  if BITS > 13                        /* Code only handles BITS = 12, 13, or 16 */
        !            95: #   define BITS        13
        !            96: #  endif
        !            97: # endif
        !            98: #endif
        !            99: 
        !           100: /*
        !           101:  * a code_int must be able to hold 2**BITS values of type int, and also -1
        !           102:  */
        !           103: #if BITS > 15
        !           104: typedef long int       code_int;
        !           105: #else
        !           106: typedef int            code_int;
        !           107: #endif
        !           108: 
        !           109: #ifdef SIGNED_COMPARE_SLOW
        !           110: typedef unsigned long int count_int;
        !           111: typedef unsigned short int count_short;
        !           112: #else
        !           113: typedef long int         count_int;
        !           114: #endif
        !           115: 
        !           116: #ifdef NO_UCHAR
        !           117:  typedef char  char_type;
        !           118: #else
        !           119:  typedef       unsigned char   char_type;
        !           120: #endif /* UCHAR */
        !           121: char_type magic_header[] = { "\037\235" };     /* 1F 9D */
        !           122: 
        !           123: /* Defines for third byte of header */
        !           124: #define BIT_MASK       0x1f
        !           125: #define BLOCK_MASK     0x80
        !           126: /* Masks 0x40 and 0x20 are free.  I think 0x20 should mean that there is
        !           127:    a fourth header byte (for expansion).
        !           128: */
        !           129: #define INIT_BITS 9                    /* initial number of bits/code */
        !           130: 
        !           131: /*
        !           132:  * compress.c - File compression ala IEEE Computer, June 1984.
        !           133:  *
        !           134:  * Authors:    Spencer W. Thomas       (decvax!harpo!utah-cs!utah-gr!thomas)
        !           135:  *             Jim McKie               (decvax!mcvax!jim)
        !           136:  *             Steve Davies            (decvax!vax135!petsd!peora!srd)
        !           137:  *             Ken Turkowski           (decvax!decwrl!turtlevax!ken)
        !           138:  *             James A. Woods          (decvax!ihnp4!ames!jaw)
        !           139:  *             Joe Orost               (decvax!vax135!petsd!joe)
        !           140:  *
        !           141:  * $Header: compress.c,v 4.0 85/07/30 12:50:00 joe Release $
        !           142:  * $Log:       compress.c,v $
        !           143:  * Revision 4.0  85/07/30  12:50:00  joe
        !           144:  * Removed ferror() calls in output routine on every output except first.
        !           145:  * Prepared for release to the world.
        !           146:  * 
        !           147:  * Revision 3.6  85/07/04  01:22:21  joe
        !           148:  * Remove much wasted storage by overlaying hash table with the tables
        !           149:  * used by decompress: tab_suffix[1<<BITS], stack[8000].  Updated USERMEM
        !           150:  * computations.  Fixed dump_tab() DEBUG routine.
        !           151:  *
        !           152:  * Revision 3.5  85/06/30  20:47:21  jaw
        !           153:  * Change hash function to use exclusive-or.  Rip out hash cache.  These
        !           154:  * speedups render the megamemory version defunct, for now.  Make decoder
        !           155:  * stack global.  Parts of the RCS trunks 2.7, 2.6, and 2.1 no longer apply.
        !           156:  *
        !           157:  * Revision 3.4  85/06/27  12:00:00  ken
        !           158:  * Get rid of all floating-point calculations by doing all compression ratio
        !           159:  * calculations in fixed point.
        !           160:  *
        !           161:  * Revision 3.3  85/06/24  21:53:24  joe
        !           162:  * Incorporate portability suggestion for M_XENIX.  Got rid of text on #else
        !           163:  * and #endif lines.  Cleaned up #ifdefs for vax and interdata.
        !           164:  *
        !           165:  * Revision 3.2  85/06/06  21:53:24  jaw
        !           166:  * Incorporate portability suggestions for Z8000, IBM PC/XT from mailing list.
        !           167:  * Default to "quiet" output (no compression statistics).
        !           168:  *
        !           169:  * Revision 3.1  85/05/12  18:56:13  jaw
        !           170:  * Integrate decompress() stack speedups (from early pointer mods by McKie).
        !           171:  * Repair multi-file USERMEM gaffe.  Unify 'force' flags to mimic semantics
        !           172:  * of SVR2 'pack'.  Streamline block-compress table clear logic.  Increase 
        !           173:  * output byte count by magic number size.
        !           174:  * 
        !           175:  * Revision 3.0   84/11/27  11:50:00  petsd!joe
        !           176:  * Set HSIZE depending on BITS.  Set BITS depending on USERMEM.  Unrolled
        !           177:  * loops in clear routines.  Added "-C" flag for 2.0 compatibility.  Used
        !           178:  * unsigned compares on Perkin-Elmer.  Fixed foreground check.
        !           179:  *
        !           180:  * Revision 2.7   84/11/16  19:35:39  ames!jaw
        !           181:  * Cache common hash codes based on input statistics; this improves
        !           182:  * performance for low-density raster images.  Pass on #ifdef bundle
        !           183:  * from Turkowski.
        !           184:  *
        !           185:  * Revision 2.6   84/11/05  19:18:21  ames!jaw
        !           186:  * Vary size of hash tables to reduce time for small files.
        !           187:  * Tune PDP-11 hash function.
        !           188:  *
        !           189:  * Revision 2.5   84/10/30  20:15:14  ames!jaw
        !           190:  * Junk chaining; replace with the simpler (and, on the VAX, faster)
        !           191:  * double hashing, discussed within.  Make block compression standard.
        !           192:  *
        !           193:  * Revision 2.4   84/10/16  11:11:11  ames!jaw
        !           194:  * Introduce adaptive reset for block compression, to boost the rate
        !           195:  * another several percent.  (See mailing list notes.)
        !           196:  *
        !           197:  * Revision 2.3   84/09/22  22:00:00  petsd!joe
        !           198:  * Implemented "-B" block compress.  Implemented REVERSE sorting of tab_next.
        !           199:  * Bug fix for last bits.  Changed fwrite to putchar loop everywhere.
        !           200:  *
        !           201:  * Revision 2.2   84/09/18  14:12:21  ames!jaw
        !           202:  * Fold in news changes, small machine typedef from thomas,
        !           203:  * #ifdef interdata from joe.
        !           204:  *
        !           205:  * Revision 2.1   84/09/10  12:34:56  ames!jaw
        !           206:  * Configured fast table lookup for 32-bit machines.
        !           207:  * This cuts user time in half for b <= FBITS, and is useful for news batching
        !           208:  * from VAX to PDP sites.  Also sped up decompress() [fwrite->putc] and
        !           209:  * added signal catcher [plus beef in writeerr()] to delete effluvia.
        !           210:  *
        !           211:  * Revision 2.0   84/08/28  22:00:00  petsd!joe
        !           212:  * Add check for foreground before prompting user.  Insert maxbits into
        !           213:  * compressed file.  Force file being uncompressed to end with ".Z".
        !           214:  * Added "-c" flag and "zcat".  Prepared for release.
        !           215:  *
        !           216:  * Revision 1.10  84/08/24  18:28:00  turtlevax!ken
        !           217:  * Will only compress regular files (no directories), added a magic number
        !           218:  * header (plus an undocumented -n flag to handle old files without headers),
        !           219:  * added -f flag to force overwriting of possibly existing destination file,
        !           220:  * otherwise the user is prompted for a response.  Will tack on a .Z to a
        !           221:  * filename if it doesn't have one when decompressing.  Will only replace
        !           222:  * file if it was compressed.
        !           223:  *
        !           224:  * Revision 1.9  84/08/16  17:28:00  turtlevax!ken
        !           225:  * Removed scanargs(), getopt(), added .Z extension and unlimited number of
        !           226:  * filenames to compress.  Flags may be clustered (-Ddvb12) or separated
        !           227:  * (-D -d -v -b 12), or combination thereof.  Modes and other status is
        !           228:  * copied with copystat().  -O bug for 4.2 seems to have disappeared with
        !           229:  * 1.8.
        !           230:  *
        !           231:  * Revision 1.8  84/08/09  23:15:00  joe
        !           232:  * Made it compatible with vax version, installed jim's fixes/enhancements
        !           233:  *
        !           234:  * Revision 1.6  84/08/01  22:08:00  joe
        !           235:  * Sped up algorithm significantly by sorting the compress chain.
        !           236:  *
        !           237:  * Revision 1.5  84/07/13  13:11:00  srd
        !           238:  * Added C version of vax asm routines.  Changed structure to arrays to
        !           239:  * save much memory.  Do unsigned compares where possible (faster on
        !           240:  * Perkin-Elmer)
        !           241:  *
        !           242:  * Revision 1.4  84/07/05  03:11:11  thomas
        !           243:  * Clean up the code a little and lint it.  (Lint complains about all
        !           244:  * the regs used in the asm, but I'm not going to "fix" this.)
        !           245:  *
        !           246:  * Revision 1.3  84/07/05  02:06:54  thomas
        !           247:  * Minor fixes.
        !           248:  *
        !           249:  * Revision 1.2  84/07/05  00:27:27  thomas
        !           250:  * Add variable bit length output.
        !           251:  *
        !           252:  */
        !           253: static char rcs_ident[] = "$Header: compress.c,v 4.0 85/07/30 12:50:00 joe Release $";
        !           254: 
        !           255: #include <stdio.h>
        !           256: #include <ctype.h>
        !           257: #include <signal.h>
        !           258: #include <sys/types.h>
        !           259: #include <sys/stat.h>
        !           260: 
        !           261: #define ARGVAL() (*++(*argv) || (--argc && *++argv))
        !           262: 
        !           263: int n_bits;                            /* number of bits/code */
        !           264: int maxbits = BITS;                    /* user settable max # bits/code */
        !           265: code_int maxcode;                      /* maximum code, given n_bits */
        !           266: code_int maxmaxcode = 1 << BITS;       /* should NEVER generate this code */
        !           267: #ifdef COMPATIBLE              /* But wrong! */
        !           268: # define MAXCODE(n_bits)       (1 << (n_bits) - 1)
        !           269: #else
        !           270: # define MAXCODE(n_bits)       ((1 << (n_bits)) - 1)
        !           271: #endif /* COMPATIBLE */
        !           272: 
        !           273: #ifdef XENIX_16
        !           274: count_int htab0[8192];
        !           275: count_int htab1[8192];
        !           276: count_int htab2[8192];
        !           277: count_int htab3[8192];
        !           278: count_int htab4[8192];
        !           279: count_int htab5[8192];
        !           280: count_int htab6[8192];
        !           281: count_int htab7[8192];
        !           282: count_int htab8[HSIZE-65536];
        !           283: count_int * htab[9] = {
        !           284:        htab0, htab1, htab2, htab3, htab4, htab5, htab6, htab7, htab8 };
        !           285: 
        !           286: #define htabof(i)      (htab[(i) >> 13][(i) & 0x1fff])
        !           287: unsigned short code0tab[16384];
        !           288: unsigned short code1tab[16384];
        !           289: unsigned short code2tab[16384];
        !           290: unsigned short code3tab[16384];
        !           291: unsigned short code4tab[16384];
        !           292: unsigned short * codetab[5] = {
        !           293:        code0tab, code1tab, code2tab, code3tab, code4tab };
        !           294: 
        !           295: #define codetabof(i)   (codetab[(i) >> 14][(i) & 0x3fff])
        !           296: 
        !           297: #else  /* Normal machine */
        !           298: count_int htab [HSIZE];
        !           299: unsigned short codetab [HSIZE];
        !           300: #define htabof(i)      htab[i]
        !           301: #define codetabof(i)   codetab[i]
        !           302: #endif /* XENIX_16 */
        !           303: code_int hsize = HSIZE;                        /* for dynamic table sizing */
        !           304: count_int fsize;
        !           305: 
        !           306: /*
        !           307:  * To save much memory, we overlay the table used by compress() with those
        !           308:  * used by decompress().  The tab_prefix table is the same size and type
        !           309:  * as the codetab.  The tab_suffix table needs 2**BITS characters.  We
        !           310:  * get this from the beginning of htab.  The output stack uses the rest
        !           311:  * of htab, and contains characters.  There is plenty of room for any
        !           312:  * possible stack (stack used to be 8000 characters).
        !           313:  */
        !           314: 
        !           315: #define tab_prefixof(i)        codetabof(i)
        !           316: #ifdef XENIX_16
        !           317: # define tab_suffixof(i)       ((char_type *)htab[(i)>>15])[(i) & 0x7fff]
        !           318: # define de_stack              ((char_type *)(htab2))
        !           319: #else  /* Normal machine */
        !           320: # define tab_suffixof(i)       ((char_type *)(htab))[i]
        !           321: # define de_stack              ((char_type *)&tab_suffixof(1<<BITS))
        !           322: #endif /* XENIX_16 */
        !           323: 
        !           324: code_int free_ent = 0;                 /* first unused entry */
        !           325: int exit_stat = 0;
        !           326: 
        !           327: code_int getcode();
        !           328: 
        !           329: Usage() {
        !           330: #ifdef DEBUG
        !           331: fprintf(stderr,"Usage: compress [-dDVfc] [-b maxbits] [file ...]\n");
        !           332: }
        !           333: int debug = 0;
        !           334: #else
        !           335: fprintf(stderr,"Usage: compress [-dfvcV] [-b maxbits] [file ...]\n");
        !           336: }
        !           337: #endif /* DEBUG */
        !           338: int nomagic = 0;       /* Use a 3-byte magic number header, unless old file */
        !           339: int zcat_flg = 0;      /* Write output on stdout, suppress messages */
        !           340: int quiet = 1;         /* don't tell me about compression */
        !           341: 
        !           342: /*
        !           343:  * block compression parameters -- after all codes are used up,
        !           344:  * and compression rate changes, start over.
        !           345:  */
        !           346: int block_compress = BLOCK_MASK;
        !           347: int clear_flg = 0;
        !           348: long int ratio = 0;
        !           349: #define CHECK_GAP 10000        /* ratio check interval */
        !           350: count_int checkpoint = CHECK_GAP;
        !           351: /*
        !           352:  * the next two codes should not be changed lightly, as they must not
        !           353:  * lie within the contiguous general code space.
        !           354:  */ 
        !           355: #define FIRST  257     /* first free entry */
        !           356: #define        CLEAR   256     /* table clear output code */
        !           357: 
        !           358: int force = 0;
        !           359: char ofname [100];
        !           360: #ifdef DEBUG
        !           361: int verbose = 0;
        !           362: #endif /* DEBUG */
        !           363: int (*bgnd_flag)();
        !           364: 
        !           365: int do_decomp = 0;
        !           366: 
        !           367: /*****************************************************************
        !           368:  * TAG( main )
        !           369:  *
        !           370:  * Algorithm from "A Technique for High Performance Data Compression",
        !           371:  * Terry A. Welch, IEEE Computer Vol 17, No 6 (June 1984), pp 8-19.
        !           372:  *
        !           373:  * Usage: compress [-dfvc] [-b bits] [file ...]
        !           374:  * Inputs:
        !           375:  *     -d:         If given, decompression is done instead.
        !           376:  *
        !           377:  *      -c:         Write output on stdout, don't remove original.
        !           378:  *
        !           379:  *      -b:         Parameter limits the max number of bits/code.
        !           380:  *
        !           381:  *     -f:         Forces output file to be generated, even if one already
        !           382:  *                 exists, and even if no space is saved by compressing.
        !           383:  *                 If -f is not used, the user will be prompted if stdin is
        !           384:  *                 a tty, otherwise, the output file will not be overwritten.
        !           385:  *
        !           386:  *      -v:        Write compression statistics
        !           387:  *
        !           388:  *     file ...:   Files to be compressed.  If none specified, stdin
        !           389:  *                 is used.
        !           390:  * Outputs:
        !           391:  *     file.Z:     Compressed form of file with same mode, owner, and utimes
        !           392:  *     or stdout   (if stdin used as input)
        !           393:  *
        !           394:  * Assumptions:
        !           395:  *     When filenames are given, replaces with the compressed version
        !           396:  *     (.Z suffix) only if the file decreases in size.
        !           397:  * Algorithm:
        !           398:  *     Modified Lempel-Ziv method (LZW).  Basically finds common
        !           399:  * substrings and replaces them with a variable size code.  This is
        !           400:  * deterministic, and can be done on the fly.  Thus, the decompression
        !           401:  * procedure needs no input table, but tracks the way the table was built.
        !           402:  */
        !           403: 
        !           404: main( argc, argv )
        !           405: register int argc; char **argv;
        !           406: {
        !           407:     int overwrite = 0; /* Do not overwrite unless given -f flag */
        !           408:     char tempname[100];
        !           409:     char **filelist, **fileptr;
        !           410:     char *cp, *rindex(), *malloc();
        !           411:     struct stat statbuf;
        !           412:     extern onintr(), oops();
        !           413: 
        !           414: 
        !           415:     if ( (bgnd_flag = signal ( SIGINT, SIG_IGN )) != SIG_IGN ) {
        !           416:        signal ( SIGINT, onintr );
        !           417:        signal ( SIGSEGV, oops );
        !           418:     }
        !           419: 
        !           420: #ifdef COMPATIBLE
        !           421:     nomagic = 1;       /* Original didn't have a magic number */
        !           422: #endif /* COMPATIBLE */
        !           423: 
        !           424:     filelist = fileptr = (char **)(malloc(argc * sizeof(*argv)));
        !           425:     *filelist = NULL;
        !           426: 
        !           427:     if((cp = rindex(argv[0], '/')) != 0) {
        !           428:        cp++;
        !           429:     } else {
        !           430:        cp = argv[0];
        !           431:     }
        !           432:     if(strcmp(cp, "uncompress") == 0) {
        !           433:        do_decomp = 1;
        !           434:     } else if(strcmp(cp, "zcat") == 0) {
        !           435:        do_decomp = 1;
        !           436:        zcat_flg = 1;
        !           437:     }
        !           438: 
        !           439: #ifdef BSD4_2
        !           440:     /* 4.2BSD dependent - take it out if not */
        !           441:     setlinebuf( stderr );
        !           442: #endif /* BSD4_2 */
        !           443: 
        !           444:     /* Argument Processing
        !           445:      * All flags are optional.
        !           446:      * -D => debug
        !           447:      * -V => print Version; debug verbose
        !           448:      * -d => do_decomp
        !           449:      * -v => unquiet
        !           450:      * -f => force overwrite of output file
        !           451:      * -n => no header: useful to uncompress old files
        !           452:      * -b maxbits => maxbits.  If -b is specified, then maxbits MUST be
        !           453:      *     given also.
        !           454:      * -c => cat all output to stdout
        !           455:      * -C => generate output compatible with compress 2.0.
        !           456:      * if a string is left, must be an input filename.
        !           457:      */
        !           458:     for (argc--, argv++; argc > 0; argc--, argv++) {
        !           459:        if (**argv == '-') {    /* A flag argument */
        !           460:            while (*++(*argv)) {        /* Process all flags in this arg */
        !           461:                switch (**argv) {
        !           462: #ifdef DEBUG
        !           463:                    case 'D':
        !           464:                        debug = 1;
        !           465:                        break;
        !           466:                    case 'V':
        !           467:                        verbose = 1;
        !           468:                        version();
        !           469:                        break;
        !           470: #else
        !           471:                    case 'V':
        !           472:                        version();
        !           473:                        break;
        !           474: #endif /* DEBUG */
        !           475:                    case 'v':
        !           476:                        quiet = 0;
        !           477:                        break;
        !           478:                    case 'd':
        !           479:                        do_decomp = 1;
        !           480:                        break;
        !           481:                    case 'f':
        !           482:                    case 'F':
        !           483:                        overwrite = 1;
        !           484:                        force = 1;
        !           485:                        break;
        !           486:                    case 'n':
        !           487:                        nomagic = 1;
        !           488:                        break;
        !           489:                    case 'C':
        !           490:                        block_compress = 0;
        !           491:                        break;
        !           492:                    case 'b':
        !           493:                        if (!ARGVAL()) {
        !           494:                            fprintf(stderr, "Missing maxbits\n");
        !           495:                            Usage();
        !           496:                            exit(1);
        !           497:                        }
        !           498:                        maxbits = atoi(*argv);
        !           499:                        goto nextarg;
        !           500:                    case 'c':
        !           501:                        zcat_flg = 1;
        !           502:                        break;
        !           503:                    case 'q':
        !           504:                        quiet = 1;
        !           505:                        break;
        !           506:                    default:
        !           507:                        fprintf(stderr, "Unknown flag: '%c'; ", **argv);
        !           508:                        Usage();
        !           509:                        exit(1);
        !           510:                }
        !           511:            }
        !           512:        }
        !           513:        else {          /* Input file name */
        !           514:            *fileptr++ = *argv; /* Build input file list */
        !           515:            *fileptr = NULL;
        !           516:            /* process nextarg; */
        !           517:        }
        !           518:        nextarg: continue;
        !           519:     }
        !           520: 
        !           521:     if(maxbits < INIT_BITS) maxbits = INIT_BITS;
        !           522:     if (maxbits > BITS) maxbits = BITS;
        !           523:     maxmaxcode = 1 << maxbits;
        !           524: 
        !           525:     if (*filelist != NULL) {
        !           526:        for (fileptr = filelist; *fileptr; fileptr++) {
        !           527:            exit_stat = 0;
        !           528:            if (do_decomp != 0) {                       /* DECOMPRESSION */
        !           529:                /* Check for .Z suffix */
        !           530:                if (strcmp(*fileptr + strlen(*fileptr) - 2, ".Z") != 0) {
        !           531:                    /* No .Z: tack one on */
        !           532:                    strcpy(tempname, *fileptr);
        !           533:                    strcat(tempname, ".Z");
        !           534:                    *fileptr = tempname;
        !           535:                }
        !           536:                /* Open input file */
        !           537:                if ((freopen(*fileptr, "r", stdin)) == NULL) {
        !           538:                        perror(*fileptr); continue;
        !           539:                }
        !           540:                /* Check the magic number */
        !           541:                if (nomagic == 0) {
        !           542:                    if ((getchar() != (magic_header[0] & 0xFF))
        !           543:                     || (getchar() != (magic_header[1] & 0xFF))) {
        !           544:                        fprintf(stderr, "%s: not in compressed format\n",
        !           545:                            *fileptr);
        !           546:                    continue;
        !           547:                    }
        !           548:                    maxbits = getchar();        /* set -b from file */
        !           549:                    block_compress = maxbits & BLOCK_MASK;
        !           550:                    maxbits &= BIT_MASK;
        !           551:                    maxmaxcode = 1 << maxbits;
        !           552:                    if(maxbits > BITS) {
        !           553:                        fprintf(stderr,
        !           554:                        "%s: compressed with %d bits, can only handle %d bits\n",
        !           555:                        *fileptr, maxbits, BITS);
        !           556:                        continue;
        !           557:                    }
        !           558:                }
        !           559:                /* Generate output filename */
        !           560:                strcpy(ofname, *fileptr);
        !           561:                ofname[strlen(*fileptr) - 2] = '\0';  /* Strip off .Z */
        !           562:            } else {                                    /* COMPRESSION */
        !           563:                if (strcmp(*fileptr + strlen(*fileptr) - 2, ".Z") == 0) {
        !           564:                        fprintf(stderr, "%s: already has .Z suffix -- no change\n",
        !           565:                            *fileptr);
        !           566:                    continue;
        !           567:                }
        !           568:                /* Open input file */
        !           569:                if ((freopen(*fileptr, "r", stdin)) == NULL) {
        !           570:                    perror(*fileptr); continue;
        !           571:                }
        !           572:                stat ( *fileptr, &statbuf );
        !           573:                fsize = (long) statbuf.st_size;
        !           574:                /*
        !           575:                 * tune hash table size for small files -- ad hoc,
        !           576:                 * but the sizes match earlier #defines, which
        !           577:                 * serve as upper bounds on the number of output codes. 
        !           578:                 */
        !           579:                hsize = HSIZE;
        !           580:                if ( fsize < (1 << 12) )
        !           581:                    hsize = min ( 5003, HSIZE );
        !           582:                else if ( fsize < (1 << 13) )
        !           583:                    hsize = min ( 9001, HSIZE );
        !           584:                else if ( fsize < (1 << 14) )
        !           585:                    hsize = min ( 18013, HSIZE );
        !           586:                else if ( fsize < (1 << 15) )
        !           587:                    hsize = min ( 35023, HSIZE );
        !           588:                else if ( fsize < 47000 )
        !           589:                    hsize = min ( 50021, HSIZE );
        !           590: 
        !           591:                /* Generate output filename */
        !           592:                strcpy(ofname, *fileptr);
        !           593: #ifndef BSD4_2         /* Short filenames */
        !           594:                if ((cp=rindex(ofname,'/')) != NULL)    cp++;
        !           595:                else                                    cp = ofname;
        !           596:                if (strlen(cp) > 12) {
        !           597:                    fprintf(stderr,"%s: filename too long to tack on .Z\n",cp);
        !           598:                    continue;
        !           599:                }
        !           600: #endif  /* BSD4_2              Long filenames allowed */
        !           601:                strcat(ofname, ".Z");
        !           602:            }
        !           603:            /* Check for overwrite of existing file */
        !           604:            if (overwrite == 0 && zcat_flg == 0) {
        !           605:                if (stat(ofname, &statbuf) == 0) {
        !           606:                    char response[2];
        !           607:                    response[0] = 'n';
        !           608:                    fprintf(stderr, "%s already exists;", ofname);
        !           609:                    if (foreground()) {
        !           610:                        fprintf(stderr, " do you wish to overwrite %s (y or n)? ",
        !           611:                        ofname);
        !           612:                        fflush(stderr);
        !           613:                        read(2, response, 2);
        !           614:                        while (response[1] != '\n') {
        !           615:                            if (read(2, response+1, 1) < 0) {   /* Ack! */
        !           616:                                perror("stderr"); break;
        !           617:                            }
        !           618:                        }
        !           619:                    }
        !           620:                    if (response[0] != 'y') {
        !           621:                        fprintf(stderr, "\tnot overwritten\n");
        !           622:                        continue;
        !           623:                    }
        !           624:                }
        !           625:            }
        !           626:            if(zcat_flg == 0) {         /* Open output file */
        !           627:                if (freopen(ofname, "w", stdout) == NULL) {
        !           628:                    perror(ofname);
        !           629:                    continue;
        !           630:                }
        !           631:                if(!quiet)
        !           632:                        fprintf(stderr, "%s: ", *fileptr);
        !           633:            }
        !           634: 
        !           635:            /* Actually do the compression/decompression */
        !           636:            if (do_decomp == 0) compress();
        !           637: #ifndef DEBUG
        !           638:            else                        decompress();
        !           639: #else
        !           640:            else if (debug == 0)        decompress();
        !           641:            else                        printcodes();
        !           642:            if (verbose)                dump_tab();
        !           643: #endif /* DEBUG */
        !           644:            if(zcat_flg == 0) {
        !           645:                copystat(*fileptr, ofname);     /* Copy stats */
        !           646:                if((exit_stat == 1) || (!quiet))
        !           647:                        putc('\n', stderr);
        !           648:            }
        !           649:        }
        !           650:     } else {           /* Standard input */
        !           651:        if (do_decomp == 0) {
        !           652:                compress();
        !           653: #ifdef DEBUG
        !           654:                if(verbose)             dump_tab();
        !           655: #endif /* DEBUG */
        !           656:                if(!quiet)
        !           657:                        putc('\n', stderr);
        !           658:        } else {
        !           659:            /* Check the magic number */
        !           660:            if (nomagic == 0) {
        !           661:                if ((getchar()!=(magic_header[0] & 0xFF))
        !           662:                 || (getchar()!=(magic_header[1] & 0xFF))) {
        !           663:                    fprintf(stderr, "stdin: not in compressed format\n");
        !           664:                    exit(1);
        !           665:                }
        !           666:                maxbits = getchar();    /* set -b from file */
        !           667:                block_compress = maxbits & BLOCK_MASK;
        !           668:                maxbits &= BIT_MASK;
        !           669:                maxmaxcode = 1 << maxbits;
        !           670:                fsize = 100000;         /* assume stdin large for USERMEM */
        !           671:                if(maxbits > BITS) {
        !           672:                        fprintf(stderr,
        !           673:                        "stdin: compressed with %d bits, can only handle %d bits\n",
        !           674:                        maxbits, BITS);
        !           675:                        exit(1);
        !           676:                }
        !           677:            }
        !           678: #ifndef DEBUG
        !           679:            decompress();
        !           680: #else
        !           681:            if (debug == 0)     decompress();
        !           682:            else                printcodes();
        !           683:            if (verbose)        dump_tab();
        !           684: #endif /* DEBUG */
        !           685:        }
        !           686:     }
        !           687:     exit(exit_stat);
        !           688: }
        !           689: 
        !           690: static int offset;
        !           691: long int in_count = 1;                 /* length of input */
        !           692: long int bytes_out;                    /* length of compressed output */
        !           693: long int out_count = 0;                        /* # of codes output (for debugging) */
        !           694: 
        !           695: /*
        !           696:  * compress stdin to stdout
        !           697:  *
        !           698:  * Algorithm:  use open addressing double hashing (no chaining) on the 
        !           699:  * prefix code / next character combination.  We do a variant of Knuth's
        !           700:  * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
        !           701:  * secondary probe.  Here, the modular division first probe is gives way
        !           702:  * to a faster exclusive-or manipulation.  Also do block compression with
        !           703:  * an adaptive reset, whereby the code table is cleared when the compression
        !           704:  * ratio decreases, but after the table fills.  The variable-length output
        !           705:  * codes are re-sized at this point, and a special CLEAR code is generated
        !           706:  * for the decompressor.  Late addition:  construct the table according to
        !           707:  * file size for noticeable speed improvement on small files.  Please direct
        !           708:  * questions about this implementation to ames!jaw.
        !           709:  */
        !           710: 
        !           711: compress() {
        !           712:     register long fcode;
        !           713:     register code_int i = 0;
        !           714:     register int c;
        !           715:     register code_int ent;
        !           716: #ifdef XENIX_16
        !           717:     register code_int disp;
        !           718: #else  /* Normal machine */
        !           719:     register int disp;
        !           720: #endif
        !           721:     register code_int hsize_reg;
        !           722:     register int hshift;
        !           723: 
        !           724: #ifndef COMPATIBLE
        !           725:     if (nomagic == 0) {
        !           726:        putchar(magic_header[0]); putchar(magic_header[1]);
        !           727:        putchar((char)(maxbits | block_compress));
        !           728:        if(ferror(stdout))
        !           729:                writeerr();
        !           730:     }
        !           731: #endif /* COMPATIBLE */
        !           732: 
        !           733:     offset = 0;
        !           734:     bytes_out = 3;             /* includes 3-byte header mojo */
        !           735:     out_count = 0;
        !           736:     clear_flg = 0;
        !           737:     ratio = 0;
        !           738:     in_count = 1;
        !           739:     checkpoint = CHECK_GAP;
        !           740:     maxcode = MAXCODE(n_bits = INIT_BITS);
        !           741:     free_ent = ((block_compress) ? FIRST : 256 );
        !           742: 
        !           743:     ent = getchar ();
        !           744: 
        !           745:     hshift = 0;
        !           746:     for ( fcode = (long) hsize;  fcode < 65536L; fcode *= 2L )
        !           747:        hshift++;
        !           748:     hshift = 8 - hshift;               /* set hash code range bound */
        !           749: 
        !           750:     hsize_reg = hsize;
        !           751:     cl_hash( (count_int) hsize_reg);           /* clear hash table */
        !           752: 
        !           753: #ifdef SIGNED_COMPARE_SLOW
        !           754:     while ( (c = getchar()) != (unsigned) EOF ) {
        !           755: #else
        !           756:     while ( (c = getchar()) != EOF ) {
        !           757: #endif
        !           758:        in_count++;
        !           759:        fcode = (long) (((long) c << maxbits) + ent);
        !           760:        i = ((c << hshift) ^ ent);      /* xor hashing */
        !           761: 
        !           762:        if ( htabof (i) == fcode ) {
        !           763:            ent = codetabof (i);
        !           764:            continue;
        !           765:        } else if ( (long)htabof (i) < 0 )      /* empty slot */
        !           766:            goto nomatch;
        !           767:        disp = hsize_reg - i;           /* secondary hash (after G. Knott) */
        !           768:        if ( i == 0 )
        !           769:            disp = 1;
        !           770: probe:
        !           771:        if ( (i -= disp) < 0 )
        !           772:            i += hsize_reg;
        !           773: 
        !           774:        if ( htabof (i) == fcode ) {
        !           775:            ent = codetabof (i);
        !           776:            continue;
        !           777:        }
        !           778:        if ( (long)htabof (i) > 0 ) 
        !           779:            goto probe;
        !           780: nomatch:
        !           781:        output ( (code_int) ent );
        !           782:        out_count++;
        !           783:        ent = c;
        !           784: #ifdef SIGNED_COMPARE_SLOW
        !           785:        if ( (unsigned) free_ent < (unsigned) maxmaxcode) {
        !           786: #else
        !           787:        if ( free_ent < maxmaxcode ) {
        !           788: #endif
        !           789:            codetabof (i) = free_ent++; /* code -> hashtable */
        !           790:            htabof (i) = fcode;
        !           791:        }
        !           792:        else if ( (count_int)in_count >= checkpoint && block_compress )
        !           793:            cl_block ();
        !           794:     }
        !           795:     /*
        !           796:      * Put out the final code.
        !           797:      */
        !           798:     output( (code_int)ent );
        !           799:     out_count++;
        !           800:     output( (code_int)-1 );
        !           801: 
        !           802:     /*
        !           803:      * Print out stats on stderr
        !           804:      */
        !           805:     if(zcat_flg == 0 && !quiet) {
        !           806: #ifdef DEBUG
        !           807:        fprintf( stderr,
        !           808:                "%ld chars in, %ld codes (%ld bytes) out, compression factor: ",
        !           809:                in_count, out_count, bytes_out );
        !           810:        prratio( stderr, in_count, bytes_out );
        !           811:        fprintf( stderr, "\n");
        !           812:        fprintf( stderr, "\tCompression as in compact: " );
        !           813:        prratio( stderr, in_count-bytes_out, in_count );
        !           814:        fprintf( stderr, "\n");
        !           815:        fprintf( stderr, "\tLargest code (of last block) was %d (%d bits)\n",
        !           816:                free_ent - 1, n_bits );
        !           817: #else /* !DEBUG */
        !           818:        fprintf( stderr, "Compression: " );
        !           819:        prratio( stderr, in_count-bytes_out, in_count );
        !           820: #endif /* DEBUG */
        !           821:     }
        !           822:     if(bytes_out > in_count)   /* exit(2) if no savings */
        !           823:        exit_stat = 2;
        !           824:     return;
        !           825: }
        !           826: 
        !           827: /*****************************************************************
        !           828:  * TAG( output )
        !           829:  *
        !           830:  * Output the given code.
        !           831:  * Inputs:
        !           832:  *     code:   A n_bits-bit integer.  If == -1, then EOF.  This assumes
        !           833:  *             that n_bits =< (long)wordsize - 1.
        !           834:  * Outputs:
        !           835:  *     Outputs code to the file.
        !           836:  * Assumptions:
        !           837:  *     Chars are 8 bits long.
        !           838:  * Algorithm:
        !           839:  *     Maintain a BITS character long buffer (so that 8 codes will
        !           840:  * fit in it exactly).  Use the VAX insv instruction to insert each
        !           841:  * code in turn.  When the buffer fills up empty it and start over.
        !           842:  */
        !           843: 
        !           844: static char buf[BITS];
        !           845: 
        !           846: #ifndef vax
        !           847: char_type lmask[9] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
        !           848: char_type rmask[9] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
        !           849: #endif /* vax */
        !           850: 
        !           851: output( code )
        !           852: code_int  code;
        !           853: {
        !           854: #ifdef DEBUG
        !           855:     static int col = 0;
        !           856: #endif /* DEBUG */
        !           857: 
        !           858:     /*
        !           859:      * On the VAX, it is important to have the register declarations
        !           860:      * in exactly the order given, or the asm will break.
        !           861:      */
        !           862:     register int r_off = offset, bits= n_bits;
        !           863:     register char * bp = buf;
        !           864: 
        !           865: #ifdef DEBUG
        !           866:        if ( verbose )
        !           867:            fprintf( stderr, "%5d%c", code,
        !           868:                    (col+=6) >= 74 ? (col = 0, '\n') : ' ' );
        !           869: #endif /* DEBUG */
        !           870:     if ( code >= 0 ) {
        !           871: #ifdef vax
        !           872:        /* VAX DEPENDENT!! Implementation on other machines is below.
        !           873:         *
        !           874:         * Translation: Insert BITS bits from the argument starting at
        !           875:         * offset bits from the beginning of buf.
        !           876:         */
        !           877:        0;      /* Work around for pcc -O bug with asm and if stmt */
        !           878:        asm( "insv      4(ap),r11,r10,(r9)" );
        !           879: #else /* not a vax */
        !           880: /* 
        !           881:  * byte/bit numbering on the VAX is simulated by the following code
        !           882:  */
        !           883:        /*
        !           884:         * Get to the first byte.
        !           885:         */
        !           886:        bp += (r_off >> 3);
        !           887:        r_off &= 7;
        !           888:        /*
        !           889:         * Since code is always >= 8 bits, only need to mask the first
        !           890:         * hunk on the left.
        !           891:         */
        !           892:        *bp = (*bp & rmask[r_off]) | (code << r_off) & lmask[r_off];
        !           893:        bp++;
        !           894:        bits -= (8 - r_off);
        !           895:        code >>= 8 - r_off;
        !           896:        /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
        !           897:        if ( bits >= 8 ) {
        !           898:            *bp++ = code;
        !           899:            code >>= 8;
        !           900:            bits -= 8;
        !           901:        }
        !           902:        /* Last bits. */
        !           903:        if(bits)
        !           904:            *bp = code;
        !           905: #endif /* vax */
        !           906:        offset += n_bits;
        !           907:        if ( offset == (n_bits << 3) ) {
        !           908:            bp = buf;
        !           909:            bits = n_bits;
        !           910:            bytes_out += bits;
        !           911:            do
        !           912:                putchar(*bp++);
        !           913:            while(--bits);
        !           914:            offset = 0;
        !           915:        }
        !           916: 
        !           917:        /*
        !           918:         * If the next entry is going to be too big for the code size,
        !           919:         * then increase it, if possible.
        !           920:         */
        !           921:        if ( free_ent > maxcode || (clear_flg > 0))
        !           922:        {
        !           923:            /*
        !           924:             * Write the whole buffer, because the input side won't
        !           925:             * discover the size increase until after it has read it.
        !           926:             */
        !           927:            if ( offset > 0 ) {
        !           928:                if( fwrite( buf, 1, n_bits, stdout ) != n_bits)
        !           929:                        writeerr();
        !           930:                bytes_out += n_bits;
        !           931:            }
        !           932:            offset = 0;
        !           933: 
        !           934:            if ( clear_flg ) {
        !           935:                maxcode = MAXCODE (n_bits = INIT_BITS);
        !           936:                clear_flg = 0;
        !           937:            }
        !           938:            else {
        !           939:                n_bits++;
        !           940:                if ( n_bits == maxbits )
        !           941:                    maxcode = maxmaxcode;
        !           942:                else
        !           943:                    maxcode = MAXCODE(n_bits);
        !           944:            }
        !           945: #ifdef DEBUG
        !           946:            if ( debug ) {
        !           947:                fprintf( stderr, "\nChange to %d bits\n", n_bits );
        !           948:                col = 0;
        !           949:            }
        !           950: #endif /* DEBUG */
        !           951:        }
        !           952:     } else {
        !           953:        /*
        !           954:         * At EOF, write the rest of the buffer.
        !           955:         */
        !           956:        if ( offset > 0 )
        !           957:            fwrite( buf, 1, (offset + 7) / 8, stdout );
        !           958:        bytes_out += (offset + 7) / 8;
        !           959:        offset = 0;
        !           960:        fflush( stdout );
        !           961: #ifdef DEBUG
        !           962:        if ( verbose )
        !           963:            fprintf( stderr, "\n" );
        !           964: #endif /* DEBUG */
        !           965:        if( ferror( stdout ) )
        !           966:                writeerr();
        !           967:     }
        !           968: }
        !           969: 
        !           970: /*
        !           971:  * Decompress stdin to stdout.  This routine adapts to the codes in the
        !           972:  * file building the "string" table on-the-fly; requiring no table to
        !           973:  * be stored in the compressed file.  The tables used herein are shared
        !           974:  * with those of the compress() routine.  See the definitions above.
        !           975:  */
        !           976: 
        !           977: decompress() {
        !           978:     register char_type *stackp;
        !           979:     register int finchar;
        !           980:     register code_int code, oldcode, incode;
        !           981: 
        !           982:     /*
        !           983:      * As above, initialize the first 256 entries in the table.
        !           984:      */
        !           985:     maxcode = MAXCODE(n_bits = INIT_BITS);
        !           986:     for ( code = 255; code >= 0; code-- ) {
        !           987:        tab_prefixof(code) = 0;
        !           988:        tab_suffixof(code) = (char_type)code;
        !           989:     }
        !           990:     free_ent = ((block_compress) ? FIRST : 256 );
        !           991: 
        !           992:     finchar = oldcode = getcode();
        !           993:     if(oldcode == -1)  /* EOF already? */
        !           994:        return;                 /* Get out of here */
        !           995:     putchar( (char)finchar );          /* first code must be 8 bits = char */
        !           996:     if(ferror(stdout))         /* Crash if can't write */
        !           997:        writeerr();
        !           998:     stackp = de_stack;
        !           999: 
        !          1000:     while ( (code = getcode()) > -1 ) {
        !          1001: 
        !          1002:        if ( (code == CLEAR) && block_compress ) {
        !          1003:            for ( code = 255; code >= 0; code-- )
        !          1004:                tab_prefixof(code) = 0;
        !          1005:            clear_flg = 1;
        !          1006:            free_ent = FIRST - 1;
        !          1007:            if ( (code = getcode ()) == -1 )    /* O, untimely death! */
        !          1008:                break;
        !          1009:        }
        !          1010:        incode = code;
        !          1011:        /*
        !          1012:         * Special case for KwKwK string.
        !          1013:         */
        !          1014:        if ( code >= free_ent ) {
        !          1015:             *stackp++ = finchar;
        !          1016:            code = oldcode;
        !          1017:        }
        !          1018: 
        !          1019:        /*
        !          1020:         * Generate output characters in reverse order
        !          1021:         */
        !          1022: #ifdef SIGNED_COMPARE_SLOW
        !          1023:        while ( ((unsigned long)code) >= ((unsigned long)256) ) {
        !          1024: #else
        !          1025:        while ( code >= 256 ) {
        !          1026: #endif
        !          1027:            *stackp++ = tab_suffixof(code);
        !          1028:            code = tab_prefixof(code);
        !          1029:        }
        !          1030:        *stackp++ = finchar = tab_suffixof(code);
        !          1031: 
        !          1032:        /*
        !          1033:         * And put them out in forward order
        !          1034:         */
        !          1035:        do
        !          1036:            putchar ( *--stackp );
        !          1037:        while ( stackp > de_stack );
        !          1038: 
        !          1039:        /*
        !          1040:         * Generate the new entry.
        !          1041:         */
        !          1042:        if ( (code=free_ent) < maxmaxcode ) {
        !          1043:            tab_prefixof(code) = (unsigned short)oldcode;
        !          1044:            tab_suffixof(code) = finchar;
        !          1045:            free_ent = code+1;
        !          1046:        } 
        !          1047:        /*
        !          1048:         * Remember previous code.
        !          1049:         */
        !          1050:        oldcode = incode;
        !          1051:     }
        !          1052:     fflush( stdout );
        !          1053:     if(ferror(stdout))
        !          1054:        writeerr();
        !          1055: }
        !          1056: 
        !          1057: /*****************************************************************
        !          1058:  * TAG( getcode )
        !          1059:  *
        !          1060:  * Read one code from the standard input.  If EOF, return -1.
        !          1061:  * Inputs:
        !          1062:  *     stdin
        !          1063:  * Outputs:
        !          1064:  *     code or -1 is returned.
        !          1065:  */
        !          1066: 
        !          1067: code_int
        !          1068: getcode() {
        !          1069:     /*
        !          1070:      * On the VAX, it is important to have the register declarations
        !          1071:      * in exactly the order given, or the asm will break.
        !          1072:      */
        !          1073:     register code_int code;
        !          1074:     static int offset = 0, size = 0;
        !          1075:     static char_type buf[BITS];
        !          1076:     register int r_off, bits;
        !          1077:     register char_type *bp = buf;
        !          1078: 
        !          1079:     if ( clear_flg > 0 || offset >= size || free_ent > maxcode ) {
        !          1080:        /*
        !          1081:         * If the next entry will be too big for the current code
        !          1082:         * size, then we must increase the size.  This implies reading
        !          1083:         * a new buffer full, too.
        !          1084:         */
        !          1085:        if ( free_ent > maxcode ) {
        !          1086:            n_bits++;
        !          1087:            if ( n_bits == maxbits )
        !          1088:                maxcode = maxmaxcode;   /* won't get any bigger now */
        !          1089:            else
        !          1090:                maxcode = MAXCODE(n_bits);
        !          1091:        }
        !          1092:        if ( clear_flg > 0) {
        !          1093:            maxcode = MAXCODE (n_bits = INIT_BITS);
        !          1094:            clear_flg = 0;
        !          1095:        }
        !          1096:        size = fread( buf, 1, n_bits, stdin );
        !          1097:        if ( size <= 0 )
        !          1098:            return -1;                  /* end of file */
        !          1099:        offset = 0;
        !          1100:        /* Round size down to integral number of codes */
        !          1101:        size = (size << 3) - (n_bits - 1);
        !          1102:     }
        !          1103:     r_off = offset;
        !          1104:     bits = n_bits;
        !          1105: #ifdef vax
        !          1106:     asm( "extzv   r10,r9,(r8),r11" );
        !          1107: #else /* not a vax */
        !          1108:        /*
        !          1109:         * Get to the first byte.
        !          1110:         */
        !          1111:        bp += (r_off >> 3);
        !          1112:        r_off &= 7;
        !          1113:        /* Get first part (low order bits) */
        !          1114: #ifdef NO_UCHAR
        !          1115:        code = ((*bp++ >> r_off) & rmask[8 - r_off]) & 0xff;
        !          1116: #else
        !          1117:        code = (*bp++ >> r_off);
        !          1118: #endif /* NO_UCHAR */
        !          1119:        bits -= (8 - r_off);
        !          1120:        r_off = 8 - r_off;              /* now, offset into code word */
        !          1121:        /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
        !          1122:        if ( bits >= 8 ) {
        !          1123: #ifdef NO_UCHAR
        !          1124:            code |= (*bp++ & 0xff) << r_off;
        !          1125: #else
        !          1126:            code |= *bp++ << r_off;
        !          1127: #endif /* NO_UCHAR */
        !          1128:            r_off += 8;
        !          1129:            bits -= 8;
        !          1130:        }
        !          1131:        /* high order bits. */
        !          1132:        code |= (*bp & rmask[bits]) << r_off;
        !          1133: #endif /* vax */
        !          1134:     offset += n_bits;
        !          1135: 
        !          1136:     return code;
        !          1137: }
        !          1138: 
        !          1139: char *
        !          1140: rindex(s, c)           /* For those who don't have it in libc.a */
        !          1141: register char *s, c;
        !          1142: {
        !          1143:        char *p;
        !          1144:        for (p = NULL; *s; s++)
        !          1145:            if (*s == c)
        !          1146:                p = s;
        !          1147:        return(p);
        !          1148: }
        !          1149: 
        !          1150: #ifdef DEBUG
        !          1151: printcodes()
        !          1152: {
        !          1153:     /*
        !          1154:      * Just print out codes from input file.  For debugging.
        !          1155:      */
        !          1156:     code_int code;
        !          1157:     int col = 0, bits;
        !          1158: 
        !          1159:     bits = n_bits = INIT_BITS;
        !          1160:     maxcode = MAXCODE(n_bits);
        !          1161:     free_ent = ((block_compress) ? FIRST : 256 );
        !          1162:     while ( ( code = getcode() ) >= 0 ) {
        !          1163:        if ( (code == CLEAR) && block_compress ) {
        !          1164:            free_ent = FIRST - 1;
        !          1165:            clear_flg = 1;
        !          1166:        }
        !          1167:        else if ( free_ent < maxmaxcode )
        !          1168:            free_ent++;
        !          1169:        if ( bits != n_bits ) {
        !          1170:            fprintf(stderr, "\nChange to %d bits\n", n_bits );
        !          1171:            bits = n_bits;
        !          1172:            col = 0;
        !          1173:        }
        !          1174:        fprintf(stderr, "%5d%c", code, (col+=6) >= 74 ? (col = 0, '\n') : ' ' );
        !          1175:     }
        !          1176:     putc( '\n', stderr );
        !          1177:     exit( 0 );
        !          1178: }
        !          1179: 
        !          1180: code_int sorttab[1<<BITS];     /* sorted pointers into htab */
        !          1181: 
        !          1182: dump_tab()     /* dump string table */
        !          1183: {
        !          1184:     register int i, first;
        !          1185:     register ent;
        !          1186: #define STACK_SIZE     15000
        !          1187:     int stack_top = STACK_SIZE;
        !          1188:     register c;
        !          1189: 
        !          1190:     if(do_decomp == 0) {       /* compressing */
        !          1191:        register int flag = 1;
        !          1192: 
        !          1193:        for(i=0; i<hsize; i++) {        /* build sort pointers */
        !          1194:                if((long)htabof(i) >= 0) {
        !          1195:                        sorttab[codetabof(i)] = i;
        !          1196:                }
        !          1197:        }
        !          1198:        first = block_compress ? FIRST : 256;
        !          1199:        for(i = first; i < free_ent; i++) {
        !          1200:                fprintf(stderr, "%5d: \"", i);
        !          1201:                de_stack[--stack_top] = '\n';
        !          1202:                de_stack[--stack_top] = '"';
        !          1203:                stack_top = in_stack((htabof(sorttab[i])>>maxbits)&0xff, 
        !          1204:                                      stack_top);
        !          1205:                for(ent=htabof(sorttab[i]) & ((1<<maxbits)-1);
        !          1206:                    ent > 256;
        !          1207:                    ent=htabof(sorttab[ent]) & ((1<<maxbits)-1)) {
        !          1208:                        stack_top = in_stack(htabof(sorttab[ent]) >> maxbits,
        !          1209:                                                stack_top);
        !          1210:                }
        !          1211:                stack_top = in_stack(ent, stack_top);
        !          1212:                fwrite( &de_stack[stack_top], 1, STACK_SIZE-stack_top, stderr);
        !          1213:                stack_top = STACK_SIZE;
        !          1214:        }
        !          1215:    } else if(!debug) { /* decompressing */
        !          1216: 
        !          1217:        for ( i = 0; i < free_ent; i++ ) {
        !          1218:           ent = i;
        !          1219:           c = tab_suffixof(ent);
        !          1220:           if ( isascii(c) && isprint(c) )
        !          1221:               fprintf( stderr, "%5d: %5d/'%c'  \"",
        !          1222:                           ent, tab_prefixof(ent), c );
        !          1223:           else
        !          1224:               fprintf( stderr, "%5d: %5d/\\%03o \"",
        !          1225:                           ent, tab_prefixof(ent), c );
        !          1226:           de_stack[--stack_top] = '\n';
        !          1227:           de_stack[--stack_top] = '"';
        !          1228:           for ( ; ent != NULL;
        !          1229:                   ent = (ent >= FIRST ? tab_prefixof(ent) : NULL) ) {
        !          1230:               stack_top = in_stack(tab_suffixof(ent), stack_top);
        !          1231:           }
        !          1232:           fwrite( &de_stack[stack_top], 1, STACK_SIZE - stack_top, stderr );
        !          1233:           stack_top = STACK_SIZE;
        !          1234:        }
        !          1235:     }
        !          1236: }
        !          1237: 
        !          1238: int
        !          1239: in_stack(c, stack_top)
        !          1240:        register c, stack_top;
        !          1241: {
        !          1242:        if ( (isascii(c) && isprint(c) && c != '\\') || c == ' ' ) {
        !          1243:            de_stack[--stack_top] = c;
        !          1244:        } else {
        !          1245:            switch( c ) {
        !          1246:            case '\n': de_stack[--stack_top] = 'n'; break;
        !          1247:            case '\t': de_stack[--stack_top] = 't'; break;
        !          1248:            case '\b': de_stack[--stack_top] = 'b'; break;
        !          1249:            case '\f': de_stack[--stack_top] = 'f'; break;
        !          1250:            case '\r': de_stack[--stack_top] = 'r'; break;
        !          1251:            case '\\': de_stack[--stack_top] = '\\'; break;
        !          1252:            default:
        !          1253:                de_stack[--stack_top] = '0' + c % 8;
        !          1254:                de_stack[--stack_top] = '0' + (c / 8) % 8;
        !          1255:                de_stack[--stack_top] = '0' + c / 64;
        !          1256:                break;
        !          1257:            }
        !          1258:            de_stack[--stack_top] = '\\';
        !          1259:        }
        !          1260:        return stack_top;
        !          1261: }
        !          1262: #endif /* DEBUG */
        !          1263: 
        !          1264: writeerr()
        !          1265: {
        !          1266:     perror ( ofname );
        !          1267:     unlink ( ofname );
        !          1268:     exit ( 1 );
        !          1269: }
        !          1270: 
        !          1271: copystat(ifname, ofname)
        !          1272: char *ifname, *ofname;
        !          1273: {
        !          1274:     struct stat statbuf;
        !          1275:     int mode;
        !          1276:     time_t timep[2];
        !          1277: 
        !          1278:     fclose(stdout);
        !          1279:     if (stat(ifname, &statbuf)) {              /* Get stat on input file */
        !          1280:        perror(ifname);
        !          1281:        return;
        !          1282:     }
        !          1283:     if ((statbuf.st_mode & S_IFMT/*0170000*/) != S_IFREG/*0100000*/) {
        !          1284:        if(quiet)
        !          1285:                fprintf(stderr, "%s: ", ifname);
        !          1286:        fprintf(stderr, " -- not a regular file: unchanged");
        !          1287:        exit_stat = 1;
        !          1288:     } else if (statbuf.st_nlink > 1) {
        !          1289:        if(quiet)
        !          1290:                fprintf(stderr, "%s: ", ifname);
        !          1291:        fprintf(stderr, " -- has %d other links: unchanged",
        !          1292:                statbuf.st_nlink - 1);
        !          1293:        exit_stat = 1;
        !          1294:     } else if (exit_stat == 2 && (!force)) { /* No compression: remove file.Z */
        !          1295:        if(!quiet)
        !          1296:                fprintf(stderr, " -- file unchanged");
        !          1297:     } else {                   /* ***** Successful Compression ***** */
        !          1298:        exit_stat = 0;
        !          1299:        mode = statbuf.st_mode & 07777;
        !          1300:        if (chmod(ofname, mode))                /* Copy modes */
        !          1301:            perror(ofname);
        !          1302:        chown(ofname, statbuf.st_uid, statbuf.st_gid);  /* Copy ownership */
        !          1303:        timep[0] = statbuf.st_atime;
        !          1304:        timep[1] = statbuf.st_mtime;
        !          1305:        utime(ofname, timep);   /* Update last accessed and modified times */
        !          1306:        if (unlink(ifname))     /* Remove input file */
        !          1307:            perror(ifname);
        !          1308:        if(!quiet)
        !          1309:                fprintf(stderr, " -- replaced with %s", ofname);
        !          1310:        return;         /* Successful return */
        !          1311:     }
        !          1312: 
        !          1313:     /* Unsuccessful return -- one of the tests failed */
        !          1314:     if (unlink(ofname))
        !          1315:        perror(ofname);
        !          1316: }
        !          1317: /*
        !          1318:  * This routine returns 1 if we are running in the foreground and stderr
        !          1319:  * is a tty.
        !          1320:  */
        !          1321: foreground()
        !          1322: {
        !          1323:        if(bgnd_flag) { /* background? */
        !          1324:                return(0);
        !          1325:        } else {                        /* foreground */
        !          1326:                if(isatty(2)) {         /* and stderr is a tty */
        !          1327:                        return(1);
        !          1328:                } else {
        !          1329:                        return(0);
        !          1330:                }
        !          1331:        }
        !          1332: }
        !          1333: 
        !          1334: onintr ( )
        !          1335: {
        !          1336:     unlink ( ofname );
        !          1337:     exit ( 1 );
        !          1338: }
        !          1339: 
        !          1340: oops ( )       /* wild pointer -- assume bad input */
        !          1341: {
        !          1342:     if ( do_decomp == 1 ) 
        !          1343:        fprintf ( stderr, "uncompress: corrupt input\n" );
        !          1344:     unlink ( ofname );
        !          1345:     exit ( 1 );
        !          1346: }
        !          1347: 
        !          1348: cl_block ()            /* table clear for block compress */
        !          1349: {
        !          1350:     register long int rat;
        !          1351: 
        !          1352:     checkpoint = in_count + CHECK_GAP;
        !          1353: #ifdef DEBUG
        !          1354:        if ( debug ) {
        !          1355:                fprintf ( stderr, "count: %ld, ratio: ", in_count );
        !          1356:                prratio ( stderr, in_count, bytes_out );
        !          1357:                fprintf ( stderr, "\n");
        !          1358:        }
        !          1359: #endif /* DEBUG */
        !          1360: 
        !          1361:     if(in_count > 0x007fffff) {        /* shift will overflow */
        !          1362:        rat = bytes_out >> 8;
        !          1363:        if(rat == 0) {          /* Don't divide by zero */
        !          1364:            rat = 0x7fffffff;
        !          1365:        } else {
        !          1366:            rat = in_count / rat;
        !          1367:        }
        !          1368:     } else {
        !          1369:        rat = (in_count << 8) / bytes_out;      /* 8 fractional bits */
        !          1370:     }
        !          1371:     if ( rat > ratio ) {
        !          1372:        ratio = rat;
        !          1373:     } else {
        !          1374:        ratio = 0;
        !          1375: #ifdef DEBUG
        !          1376:        if(verbose)
        !          1377:                dump_tab();     /* dump string table */
        !          1378: #endif
        !          1379:        cl_hash ( (count_int) hsize );
        !          1380:        free_ent = FIRST;
        !          1381:        clear_flg = 1;
        !          1382:        output ( (code_int) CLEAR );
        !          1383: #ifdef DEBUG
        !          1384:        if(debug)
        !          1385:                fprintf ( stderr, "clear\n" );
        !          1386: #endif /* DEBUG */
        !          1387:     }
        !          1388: }
        !          1389: 
        !          1390: cl_hash(hsize)         /* reset code table */
        !          1391:        register count_int hsize;
        !          1392: {
        !          1393: #ifndef XENIX_16       /* Normal machine */
        !          1394:        register count_int *htab_p = htab+hsize;
        !          1395: #else
        !          1396:        register j;
        !          1397:        register long k = hsize;
        !          1398:        register count_int *htab_p;
        !          1399: #endif
        !          1400:        register long i;
        !          1401:        register long m1 = -1;
        !          1402: 
        !          1403: #ifdef XENIX_16
        !          1404:     for(j=0; j<=8 && k>=0; j++,k-=8192) {
        !          1405:        i = 8192;
        !          1406:        if(k < 8192) {
        !          1407:                i = k;
        !          1408:        }
        !          1409:        htab_p = &(htab[j][i]);
        !          1410:        i -= 16;
        !          1411:        if(i > 0) {
        !          1412: #else
        !          1413:        i = hsize - 16;
        !          1414: #endif
        !          1415:        do {                            /* might use Sys V memset(3) here */
        !          1416:                *(htab_p-16) = m1;
        !          1417:                *(htab_p-15) = m1;
        !          1418:                *(htab_p-14) = m1;
        !          1419:                *(htab_p-13) = m1;
        !          1420:                *(htab_p-12) = m1;
        !          1421:                *(htab_p-11) = m1;
        !          1422:                *(htab_p-10) = m1;
        !          1423:                *(htab_p-9) = m1;
        !          1424:                *(htab_p-8) = m1;
        !          1425:                *(htab_p-7) = m1;
        !          1426:                *(htab_p-6) = m1;
        !          1427:                *(htab_p-5) = m1;
        !          1428:                *(htab_p-4) = m1;
        !          1429:                *(htab_p-3) = m1;
        !          1430:                *(htab_p-2) = m1;
        !          1431:                *(htab_p-1) = m1;
        !          1432:                htab_p -= 16;
        !          1433:        } while ((i -= 16) >= 0);
        !          1434: #ifdef XENIX_16
        !          1435:        }
        !          1436:     }
        !          1437: #endif
        !          1438:        for ( i += 16; i > 0; i-- )
        !          1439:                *--htab_p = m1;
        !          1440: }
        !          1441: 
        !          1442: prratio(stream, num, den)
        !          1443: FILE *stream;
        !          1444: long int num, den;
        !          1445: {
        !          1446:        register int q;                 /* Doesn't need to be long */
        !          1447: 
        !          1448:        if(num > 214748L) {             /* 2147483647/10000 */
        !          1449:                q = num / (den / 10000L);
        !          1450:        } else {
        !          1451:                q = 10000L * num / den;         /* Long calculations, though */
        !          1452:        }
        !          1453:        if (q < 0) {
        !          1454:                putc('-', stream);
        !          1455:                q = -q;
        !          1456:        }
        !          1457:        fprintf(stream, "%d.%02d%%", q / 100, q % 100);
        !          1458: }
        !          1459: 
        !          1460: version()
        !          1461: {
        !          1462:        fprintf(stderr, "%s\n", rcs_ident);
        !          1463:        fprintf(stderr, "Options: ");
        !          1464: #ifdef vax
        !          1465:        fprintf(stderr, "vax, ");
        !          1466: #endif
        !          1467: #ifdef NO_UCHAR
        !          1468:        fprintf(stderr, "NO_UCHAR, ");
        !          1469: #endif
        !          1470: #ifdef SIGNED_COMPARE_SLOW
        !          1471:        fprintf(stderr, "SIGNED_COMPARE_SLOW, ");
        !          1472: #endif
        !          1473: #ifdef XENIX_16
        !          1474:        fprintf(stderr, "XENIX_16, ");
        !          1475: #endif
        !          1476: #ifdef COMPATIBLE
        !          1477:        fprintf(stderr, "COMPATIBLE, ");
        !          1478: #endif
        !          1479: #ifdef DEBUG
        !          1480:        fprintf(stderr, "DEBUG, ");
        !          1481: #endif
        !          1482: #ifdef BSD4_2
        !          1483:        fprintf(stderr, "BSD4_2, ");
        !          1484: #endif
        !          1485:        fprintf(stderr, "BITS = %d\n", BITS);
        !          1486: }

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