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Annotation of researchv8dc/cmd/compress/compress.c, revision 1.1

1.1     ! root        1: /* Set USERMEM to the maximum amount of physical user memory available
        !             2:  * in bytes.  USERMEM is used to determine the maximum BITS that can be used
        !             3:  * for compression.  If USERMEM is big enough, use fast compression algorithm.
        !             4:  *
        !             5:  * SACREDMEM is the amount of physical memory saved for others; compress
        !             6:  * will hog the rest.
        !             7:  */
        !             8: #ifndef SACREDMEM
        !             9: #define SACREDMEM      0
        !            10: #endif
        !            11: 
        !            12: #ifdef pdp11
        !            13: # define BITS  12      /* max bits/code for 16-bit machine */
        !            14: # define NO_UCHAR      /* also if "unsigned char" functions as signed char */
        !            15: # define SHORT_INT     /* ints are short */
        !            16: # undef USERMEM 
        !            17: #else !pdp11
        !            18: # ifndef USERMEM
        !            19: #  define USERMEM 750000       /* default user memory */
        !            20: # endif
        !            21: #endif !pdp11
        !            22: /* 
        !            23:  * Define FBITS for machines with several MB of physical memory, to use
        !            24:  * table lookup for (b <= FBITS).  If FBITS is made too large, performance
        !            25:  * will decrease due to increased swapping/paging.  Since the program minus
        !            26:  * the fast lookup table is about a half Meg, we can allocate the rest of
        !            27:  * available physical memory to the fast lookup table.
        !            28:  * 
        !            29:  * If FBITS is set to 12, a 2 MB array is allocated, but only 1 MB is
        !            30:  * addressed for parity-free input (i.e. text).
        !            31:  *
        !            32:  * FBITS=10 yields 1/2 meg lookup table + 4K code memory
        !            33:  * FBITS=11 yields 1 meg lookup table + 8K code memory
        !            34:  * FBITS=12 yields 2 meg lookup table + 16K code memory
        !            35:  * FBITS=13 yields 4 meg lookup table + 32K code memory
        !            36:  *
        !            37:  */
        !            38: 
        !            39: #ifdef USERMEM
        !            40: # if USERMEM >= (2621440+SACREDMEM)
        !            41: #  if USERMEM >= (4718592+SACREDMEM)
        !            42: #   define FBITS               13
        !            43: #   define PBITS       16
        !            44: #  else 2.5M <= USERMEM < 4.5M
        !            45: #   define FBITS               12
        !            46: #   define PBITS       16
        !            47: #  endif USERMEM <=> 4.5M
        !            48: # else USERMEM < 2.5M
        !            49: #  if USERMEM >= (1572864+SACREDMEM)
        !            50: #   define FBITS               11
        !            51: #   define PBITS       16
        !            52: #  else USERMEM < 1.5M
        !            53: #   if USERMEM >= (1048576+SACREDMEM)
        !            54: #    define FBITS              10
        !            55: #    define PBITS      16
        !            56: #   else USERMEM < 1M
        !            57: #    if USERMEM >= (631808+SACREDMEM)
        !            58: #     define PBITS     16
        !            59: #    else
        !            60: #     if USERMEM >= (329728+SACREDMEM)
        !            61: #      define PBITS    15
        !            62: #     else
        !            63: #      if USERMEM >= (178176+SACREDMEM)
        !            64: #       define PBITS   14
        !            65: #      else
        !            66: #       if USERMEM >= (99328+SACREDMEM)
        !            67: #        define PBITS  13
        !            68: #       else
        !            69: #        define PBITS  12
        !            70: #       endif
        !            71: #      endif
        !            72: #     endif
        !            73: #    endif
        !            74: #    undef USERMEM
        !            75: #   endif USERMEM <=> 1M
        !            76: #  endif USERMEM <=> 1.5M
        !            77: # endif USERMEM <=> 2.5M
        !            78: #endif USERMEM
        !            79: 
        !            80: #ifdef PBITS           /* Preferred BITS for this memory size */
        !            81: # ifndef BITS
        !            82: #  define BITS PBITS
        !            83: # endif BITS
        !            84: #endif PBITS
        !            85: 
        !            86: #if BITS == 16
        !            87: # define HSIZE 69001           /* 95% occupancy */
        !            88: #endif
        !            89: #if BITS == 15
        !            90: # define HSIZE 35023           /* 94% occupancy */
        !            91: #endif
        !            92: #if BITS == 14
        !            93: # define HSIZE 18013           /* 91% occupancy */
        !            94: #endif
        !            95: #if BITS == 13
        !            96: # define HSIZE 9001            /* 91% occupancy */
        !            97: #endif
        !            98: #if BITS == 12
        !            99: # define HSIZE 5003            /* 80% occupancy */
        !           100: #endif
        !           101: #if BITS == 11
        !           102: # define HSIZE 2591            /* 79% occupancy */
        !           103: #endif
        !           104: #if BITS == 10
        !           105: # define HSIZE 1291            /* 79% occupancy */
        !           106: #endif
        !           107: #if BITS == 9
        !           108: # define HSIZE 691             /* 74% occupancy */
        !           109: #endif
        !           110: /* BITS < 9 will cause an error */
        !           111: 
        !           112: /*
        !           113:  * a code_int must be able to hold 2**BITS values of type int, and also -1
        !           114:  */
        !           115: #if BITS > 15
        !           116: typedef long int       code_int;
        !           117: #else
        !           118: typedef int            code_int;
        !           119: #endif
        !           120: 
        !           121: #ifdef interdata
        !           122: typedef unsigned long int count_int;
        !           123: typedef unsigned short int count_short;
        !           124: #else
        !           125: typedef long int         count_int;
        !           126: #endif
        !           127: 
        !           128: #ifdef NO_UCHAR
        !           129:  typedef char  char_type;
        !           130: #else UCHAR
        !           131:  typedef       unsigned char   char_type;
        !           132: #endif UCHAR
        !           133: char_type magic_header[] = { "\037\235" };     /* 1F 9D */
        !           134: 
        !           135: /* Defines for third byte of header */
        !           136: #define BIT_MASK       0x1f
        !           137: #define BLOCK_MASK     0x80
        !           138: /* Masks 0x40 and 0x20 are free.  I think 0x20 should mean that there is
        !           139:    a fourth header byte (for expansion).
        !           140: */
        !           141: #define INIT_BITS 9                    /* initial number of bits/code */
        !           142: 
        !           143: /*
        !           144:  * compress.c - File compression ala IEEE Computer June 1984.
        !           145:  *
        !           146:  * Authors:    Spencer W. Thomas       (decvax!harpo!utah-cs!utah-gr!thomas)
        !           147:  *             Jim McKie               (decvax!mcvax!jim)
        !           148:  *             Steve Davies            (decvax!vax135!petsd!peora!srd)
        !           149:  *             Ken Turkowski           (decvax!decwrl!turtlevax!ken)
        !           150:  *             James A. Woods          (decvax!ihnp4!ames!jaw)
        !           151:  *             Joe Orost               (decvax!vax135!petsd!joe)
        !           152:  *
        !           153:  * $Header: compress.c,v 3.0 84/11/27 11:50:00 joe Exp $
        !           154:  * $Log:       compress.c,v $
        !           155:  * Revision 3.0   84/11/27  11:50:00  petsd!joe
        !           156:  * Set HSIZE depending on BITS.  Set BITS depending on USERMEM.  Unrolled
        !           157:  * loops in clear routines.  Added "-C" flag for 2.0 compatability.  Used
        !           158:  * unsigned compares on Perkin-Elmer.  Fixed foreground check.
        !           159:  *
        !           160:  * Revision 2.7   84/11/16  19:35:39  ames!jaw
        !           161:  * Cache common hash codes based on input statistics; this improves
        !           162:  * performance for low-density raster images.  Pass on #ifdef bundle
        !           163:  * from Turkowski.
        !           164:  *
        !           165:  * Revision 2.6   84/11/05  19:18:21  ames!jaw
        !           166:  * Vary size of hash tables to reduce time for small files.
        !           167:  * Tune PDP-11 hash function.
        !           168:  *
        !           169:  * Revision 2.5   84/10/30  20:15:14  ames!jaw
        !           170:  * Junk chaining; replace with the simpler (and, on the VAX, faster)
        !           171:  * double hashing, discussed within.  Make block compression standard.
        !           172:  *
        !           173:  * Revision 2.4   84/10/16  11:11:11  ames!jaw
        !           174:  * Introduce adaptive reset for block compression, to boost the rate
        !           175:  * another several percent.  (See mailing list notes.)
        !           176:  *
        !           177:  * Revision 2.3   84/09/22  22:00:00  petsd!joe
        !           178:  * Implemented "-B" block compress.  Implemented REVERSE sorting of tab_next.
        !           179:  * Bug fix for last bits.  Changed fwrite to putchar loop everywhere.
        !           180:  *
        !           181:  * Revision 2.2   84/09/18  14:12:21  ames!jaw
        !           182:  * Fold in news changes, small machine typedef from thomas,
        !           183:  * #ifdef interdata from joe.
        !           184:  *
        !           185:  * Revision 2.1   84/09/10  12:34:56  ames!jaw
        !           186:  * Configured fast table lookup for 32-bit machines.
        !           187:  * This cuts user time in half for b <= FBITS, and is useful for news batching
        !           188:  * from VAX to PDP sites.  Also sped up decompress() [fwrite->putc] and
        !           189:  * added signal catcher [plus beef in writeerr()] to delete effluvia.
        !           190:  *
        !           191:  * Revision 2.0   84/08/28  22:00:00  petsd!joe
        !           192:  * Add check for foreground before prompting user.  Insert maxbits into
        !           193:  * compressed file.  Force file being uncompressed to end with ".Z".
        !           194:  * Added "-c" flag and "zcat".  Prepared for release.
        !           195:  *
        !           196:  * Revision 1.10  84/08/24  18:28:00  turtlevax!ken
        !           197:  * Will only compress regular files (no directories), added a magic number
        !           198:  * header (plus an undocumented -n flag to handle old files without headers),
        !           199:  * added -f flag to force overwriting of possibly existing destination file,
        !           200:  * otherwise the user is prompted for a response.  Will tack on a .Z to a
        !           201:  * filename if it doesn't have one when decompressing.  Will only replace
        !           202:  * file if it was compressed.
        !           203:  *
        !           204:  * Revision 1.9  84/08/16  17:28:00  turtlevax!ken
        !           205:  * Removed scanargs(), getopt(), added .Z extension and unlimited number of
        !           206:  * filenames to compress.  Flags may be clustered (-Ddvb12) or separated
        !           207:  * (-D -d -v -b 12), or combination thereof.  Modes and other status is
        !           208:  * copied with copystat().  -O bug for 4.2 seems to have disappeared with
        !           209:  * 1.8.
        !           210:  *
        !           211:  * Revision 1.8  84/08/09  23:15:00  joe
        !           212:  * Made it compatible with vax version, installed jim's fixes/enhancements
        !           213:  *
        !           214:  * Revision 1.6  84/08/01  22:08:00  joe
        !           215:  * Sped up algorithm significantly by sorting the compress chain.
        !           216:  *
        !           217:  * Revision 1.5  84/07/13  13:11:00  srd
        !           218:  * Added C version of vax asm routines.  Changed structure to arrays to
        !           219:  * save much memory.  Do unsigned compares where possible (faster on
        !           220:  * Perkin-Elmer)
        !           221:  *
        !           222:  * Revision 1.4  84/07/05  03:11:11  thomas
        !           223:  * Clean up the code a little and lint it.  (Lint complains about all
        !           224:  * the regs used in the asm, but I'm not going to "fix" this.)
        !           225:  *
        !           226:  * Revision 1.3  84/07/05  02:06:54  thomas
        !           227:  * Minor fixes.
        !           228:  *
        !           229:  * Revision 1.2  84/07/05  00:27:27  thomas
        !           230:  * Add variable bit length output.
        !           231:  *
        !           232:  */
        !           233: #ifndef lint
        !           234: static char rcs_ident[] = "$Header: compress.c,v 3.0 84/11/27 11:50:00 joe Exp $";
        !           235: #endif !lint
        !           236: 
        !           237: #include <stdio.h>
        !           238: #include <ctype.h>
        !           239: #include <signal.h>
        !           240: #include <sys/types.h>
        !           241: #include <sys/stat.h>
        !           242: 
        !           243: #define ARGVAL() (*++(*argv) || (--argc && *++argv))
        !           244: 
        !           245: int n_bits;                            /* number of bits/code */
        !           246: int maxbits = BITS;                    /* user settable max # bits/code */
        !           247: code_int maxcode;                      /* maximum code, given n_bits */
        !           248: code_int maxmaxcode = 1 << BITS;       /* should NEVER generate this code */
        !           249: #ifdef COMPATIBLE              /* But wrong! */
        !           250: # define MAXCODE(n_bits)       (1 << (n_bits) - 1)
        !           251: #else COMPATIBLE
        !           252: # define MAXCODE(n_bits)       ((1 << (n_bits)) - 1)
        !           253: #endif COMPATIBLE
        !           254: 
        !           255: /*
        !           256:  * One code could conceivably represent (1<<BITS) characters, but
        !           257:  * to get a code of length N requires an input string of at least
        !           258:  * N*(N-1)/2 characters.  With 5000 chars in the stack, an input
        !           259:  * file would have to contain a 25Mb string of a single character.
        !           260:  * This seems unlikely.
        !           261:  */
        !           262: #ifdef SHORT_INT
        !           263: # define MAXSTACK    5000              /* size of output stack */
        !           264: #else !SHORT_INT
        !           265: # define MAXSTACK    8000              /* size of output stack */
        !           266: #endif !SHORT_INT
        !           267: 
        !           268: count_int htab [HSIZE];
        !           269: unsigned short codetab [HSIZE];
        !           270: code_int hsize = HSIZE;                        /* for dynamic table sizing */
        !           271: count_int fsize;
        !           272: 
        !           273: #define tab_prefix     codetab         /* prefix code for this entry */
        !           274: char_type      tab_suffix[1<<BITS];    /* last char in this entry */
        !           275: 
        !           276: #ifdef USERMEM
        !           277: short ftable [(1 << FBITS) * 256];
        !           278: count_int fcodemem [1 << FBITS];
        !           279: #endif USERMEM
        !           280: 
        !           281: code_int free_ent = 0;                 /* first unused entry */
        !           282: int exit_stat = 0;
        !           283: 
        !           284: code_int getcode();
        !           285: 
        !           286: Usage() {
        !           287: #ifdef DEBUG
        !           288: fprintf(stderr,"Usage: compress [-dDvqfFc] [-b maxbits] [file ...]\n");
        !           289: }
        !           290: int debug = 0;
        !           291: #else DEBUG
        !           292: fprintf(stderr,"Usage: compress [-dfFqc] [-b maxbits] [file ...]\n");
        !           293: }
        !           294: #endif DEBUG
        !           295: int nomagic = 0;       /* Use a 2 byte magic number header, unless old file */
        !           296: int zcat_flg = 0;      /* Write output on stdout, suppress messages */
        !           297: int quiet = 0;         /* don't tell me about compression */
        !           298: 
        !           299: /*
        !           300:  * block compression parameters -- after all codes are used up,
        !           301:  * and compression rate changes, start over.
        !           302:  */
        !           303: int block_compress = BLOCK_MASK;
        !           304: int clear_flg = 0;
        !           305: double ratio = 0.0;    /* compression ratio for last block */
        !           306: #define CHECK_GAP 10000        /* ratio check interval */
        !           307: count_int checkpoint = CHECK_GAP;
        !           308: /*
        !           309:  * the next two codes should not be changed lightly, as they must not
        !           310:  * lie within the contiguous general code space.
        !           311:  */ 
        !           312: #define FIRST  257     /* first free entry */
        !           313: #define        CLEAR   256     /* table clear output code */
        !           314: 
        !           315: int force = 0;
        !           316: char ofname [100];
        !           317: #ifdef DEBUG
        !           318: int verbose = 0;
        !           319: #endif DEBUG
        !           320: int (*bgnd_flag)();
        !           321: 
        !           322: /*****************************************************************
        !           323:  * TAG( main )
        !           324:  *
        !           325:  * Algorithm from "A Technique for High Performance Data Compression",
        !           326:  * Terry A. Welch, IEEE Computer Vol 17, No 6 (June 1984), pp 8-19.
        !           327:  *
        !           328:  * Usage: compress [-dfFqc] [-b bits] [file ...]
        !           329:  * Inputs:
        !           330:  *     -d:         If given, decompression is done instead.
        !           331:  *
        !           332:  *      -c:         Write output on stdout, don't remove original.
        !           333:  *
        !           334:  *      -b:         Parameter limits the max number of bits/code.
        !           335:  *
        !           336:  *     -f:         Forces output file to be generated, even if one already
        !           337:  *                 exists; if -f is not used, the user will be prompted if
        !           338:  *                 the stdin is a tty, otherwise, the output file will not
        !           339:  *                 be overwritten.
        !           340:  *
        !           341:  *     -F:         Forces output file to be generated, even if no space is
        !           342:  *                 saved by compressing.
        !           343:  *
        !           344:  *     -q:         No output, unless error
        !           345:  *
        !           346:  *     file ...:   Files to be compressed.  If none specified, stdin
        !           347:  *                 is used.
        !           348:  * Outputs:
        !           349:  *     file.Z:     Compressed form of file with same mode, owner, and utimes
        !           350:  *     or stdout   (if stdin used as input)
        !           351:  *
        !           352:  * Assumptions:
        !           353:  *     When filenames are given, replaces with the compressed version
        !           354:  *     (.Z suffix) only if the file decreased in size.
        !           355:  * Algorithm:
        !           356:  *     Modified Lempel-Ziv method (LZW).  Basically finds common
        !           357:  * substrings and replaces them with a variable size code.  This is
        !           358:  * deterministic, and can be done on the fly.  Thus, the decompression
        !           359:  * procedure needs no input table, but tracks the way the table was
        !           360:  * built.
        !           361:  */
        !           362: 
        !           363: main( argc, argv )
        !           364: register int argc; char **argv;
        !           365: {
        !           366:     int do_decomp = 0;
        !           367:     int overwrite = 0; /* Do not overwrite unless given -f flag */
        !           368:     char tempname[100];
        !           369:     char **filelist, **fileptr;
        !           370:     char *cp, *rindex();
        !           371:     struct stat statbuf;
        !           372:     extern onintr();
        !           373: 
        !           374: 
        !           375:     if ( (bgnd_flag = signal ( SIGINT, SIG_IGN )) != SIG_IGN )
        !           376:        signal ( SIGINT, onintr );
        !           377: 
        !           378: #ifdef COMPATIBLE
        !           379:     nomagic = 1;       /* Original didn't have a magic number */
        !           380: #endif COMPATIBLE
        !           381: 
        !           382:     filelist = fileptr = (char **)(malloc(argc * sizeof(*argv)));
        !           383:     *filelist = NULL;
        !           384: 
        !           385:     if((cp = rindex(argv[0], '/')) != 0) {
        !           386:        cp++;
        !           387:     } else {
        !           388:        cp = argv[0];
        !           389:     }
        !           390:     if(strcmp(cp, "uncompress") == 0) {
        !           391:        do_decomp = 1;
        !           392:     } else if(strcmp(cp, "zcat") == 0) {
        !           393:        do_decomp = 1;
        !           394:        zcat_flg = 1;
        !           395:     }
        !           396: 
        !           397: #ifdef BSD4_2
        !           398:     /* 4.2BSD dependent - take it out if not */
        !           399:     setlinebuf( stderr );
        !           400: #endif BSD4_2
        !           401: 
        !           402:     /* Argument Processing
        !           403:      * All flags are optional.
        !           404:      * -D => debug
        !           405:      * -d => do_decomp
        !           406:      * -v => verbose
        !           407:      * -f => force overwrite of output file
        !           408:      * -n => no header: useful to uncompress old files
        !           409:      * -b maxbits => maxbits.  If -b is specified, then maxbits MUST be
        !           410:      *     given also.
        !           411:      * -c => cat all output to stdout
        !           412:      * -C => generate output compatable with compress 2.0.
        !           413:      * if a string is left, must be an input filename.
        !           414:      */
        !           415:     for (argc--, argv++; argc > 0; argc--, argv++) {
        !           416:        if (**argv == '-') {    /* A flag argument */
        !           417:            while (*++(*argv)) {        /* Process all flags in this arg */
        !           418:                switch (**argv) {
        !           419: #ifdef DEBUG
        !           420:                    case 'D':
        !           421:                        debug = 1;
        !           422:                        break;
        !           423:                    case 'v':
        !           424:                        verbose = 1;
        !           425:                        break;
        !           426: #endif DEBUG
        !           427:                    case 'd':
        !           428:                        do_decomp = 1;
        !           429:                        break;
        !           430:                    case 'f':
        !           431:                        overwrite = 1;
        !           432:                        break;
        !           433:                    case 'n':
        !           434:                        nomagic = 1;
        !           435:                        break;
        !           436:                    case 'C':
        !           437:                        block_compress = 0;
        !           438:                        break;
        !           439:                    case 'b':
        !           440:                        if (!ARGVAL()) {
        !           441:                            fprintf(stderr, "Missing maxbits\n");
        !           442:                            Usage();
        !           443:                            exit(1);
        !           444:                        }
        !           445:                        maxbits = atoi(*argv);
        !           446:                        goto nextarg;
        !           447:                    case 'c':
        !           448:                        zcat_flg = 1;
        !           449:                        break;
        !           450:                    case 'q':
        !           451:                        quiet = 1;
        !           452:                        break;
        !           453:                    case 'F':
        !           454:                        force = 1;
        !           455:                        break;
        !           456:                    default:
        !           457:                        fprintf(stderr, "Unknown flag: '%c'; ", **argv);
        !           458:                        Usage();
        !           459:                        exit(1);
        !           460:                }
        !           461:            }
        !           462:        }
        !           463:        else {          /* Input file name */
        !           464:            *fileptr++ = *argv; /* Build input file list */
        !           465:            *fileptr = NULL;
        !           466:            /* goto nextarg; */
        !           467:        }
        !           468:        nextarg: continue;
        !           469:     }
        !           470: 
        !           471:     if(maxbits < INIT_BITS) maxbits = INIT_BITS;
        !           472:     if (maxbits > BITS) maxbits = BITS;
        !           473:     maxmaxcode = 1 << maxbits;
        !           474: 
        !           475:     if (*filelist != NULL) {
        !           476:        for (fileptr = filelist; *fileptr; fileptr++) {
        !           477:            exit_stat = 0;
        !           478:            if (do_decomp != 0) {                       /* DECOMPRESSION */
        !           479:                /* Check for .Z suffix */
        !           480:                if (strcmp(*fileptr + strlen(*fileptr) - 2, ".Z") != 0) {
        !           481:                    /* No .Z: tack one on */
        !           482:                    strcpy(tempname, *fileptr);
        !           483:                    strcat(tempname, ".Z");
        !           484:                    *fileptr = tempname;
        !           485:                }
        !           486:                /* Open input file */
        !           487:                if ((freopen(*fileptr, "r", stdin)) == NULL) {
        !           488:                        perror(*fileptr); continue;
        !           489:                }
        !           490:                /* Check the magic number */
        !           491:                if (nomagic == 0) {
        !           492:                    if ((getchar() != (magic_header[0] & 0xFF))
        !           493:                     || (getchar() != (magic_header[1] & 0xFF))) {
        !           494:                        fprintf(stderr, "%s: not in compressed format\n",
        !           495:                            *fileptr);
        !           496:                    continue;
        !           497:                    }
        !           498:                    maxbits = getchar();        /* set -b from file */
        !           499:                    block_compress = maxbits & BLOCK_MASK;
        !           500:                    maxbits &= BIT_MASK;
        !           501:                    maxmaxcode = 1 << maxbits;
        !           502:                    if(maxbits > BITS) {
        !           503:                        fprintf(stderr,
        !           504:                        "%s: compressed with %d bits, can only handle %d bits\n",
        !           505:                        *fileptr, maxbits, BITS);
        !           506:                        continue;
        !           507:                    }
        !           508:                }
        !           509:                /* Generate output filename */
        !           510:                strcpy(ofname, *fileptr);
        !           511:                ofname[strlen(*fileptr) - 2] = '\0';  /* Strip off .Z */
        !           512:            } else {                                    /* COMPRESSION */
        !           513:                if (strcmp(*fileptr + strlen(*fileptr) - 2, ".Z") == 0) {
        !           514:                    fprintf(stderr, "%s: already has .Z suffix -- no change\n",
        !           515:                            *fileptr);
        !           516:                    continue;
        !           517:                }
        !           518:                /* Open input file */
        !           519:                if ((freopen(*fileptr, "r", stdin)) == NULL) {
        !           520:                    perror(*fileptr); continue;
        !           521:                }
        !           522:                stat ( *fileptr, &statbuf );
        !           523:                fsize = (long) statbuf.st_size;
        !           524:                /*
        !           525:                 * tune hash table size for small files -- ad hoc
        !           526:                 */
        !           527: #if HSIZE > 5003
        !           528:                if ( fsize < (1 << 12) )
        !           529:                    hsize = 5003;
        !           530: #if HSIZE > 9001
        !           531:                else if ( fsize < (1 << 13) )
        !           532:                    hsize = 9001;
        !           533: #if HSIZE > 18013
        !           534:                else if ( fsize < (1 << 14) )
        !           535:                    hsize = 18013;
        !           536: #if HSIZE > 35023
        !           537:                else if ( fsize < (1 << 15) )
        !           538:                    hsize = 35023;
        !           539:                else if ( fsize < 47000 )
        !           540:                    hsize = 50021;
        !           541: #endif HSIZE > 35023
        !           542: #endif HSIZE > 18013
        !           543: #endif HSIZE > 9001
        !           544:                else
        !           545: #endif HSIZE > 5003
        !           546:                    hsize = HSIZE;
        !           547:                /* Generate output filename */
        !           548:                strcpy(ofname, *fileptr);
        !           549: #ifndef BSD4_2         /* Short filenames */
        !           550:                if ((cp=rindex(ofname,'/')) != NULL)    cp++;
        !           551:                else                                    cp = ofname;
        !           552:                if (strlen(cp) > 12) {
        !           553:                    fprintf(stderr,"%s: filename too long to tack on .Z\n",cp);
        !           554:                    continue;
        !           555:                }
        !           556: #endif  BSD4_2         /* Long filenames allowed */
        !           557:                strcat(ofname, ".Z");
        !           558:            }
        !           559:            /* Check for overwrite of existing file */
        !           560:            if (overwrite == 0 && zcat_flg == 0) {
        !           561:                if (stat(ofname, &statbuf) == 0) {
        !           562:                    char response[2];
        !           563:                    response[0] = 'n';
        !           564:                    fprintf(stderr, "%s already exists;", ofname);
        !           565:                    if (foreground()) {
        !           566:                        fprintf(stderr, " do you wish to overwrite (y or n)? ",
        !           567:                        ofname);
        !           568:                        fflush(stderr);
        !           569:                        read(2, response, 2);
        !           570:                        while (response[1] != '\n') {
        !           571:                            if (read(2, response+1, 1) < 0) {   /* Ack! */
        !           572:                                perror("stderr"); break;
        !           573:                            }
        !           574:                        }
        !           575:                    }
        !           576:                    if (response[0] != 'y') {
        !           577:                        fprintf(stderr, "\tnot overwritten\n");
        !           578:                        continue;
        !           579:                    }
        !           580:                }
        !           581:            }
        !           582:            if(zcat_flg == 0) {         /* Open output file */
        !           583:                if (freopen(ofname, "w", stdout) == NULL) {
        !           584:                    perror(ofname);
        !           585:                    continue;
        !           586:                }
        !           587:                if(!quiet)
        !           588:                        fprintf(stderr, "%s: ", *fileptr);
        !           589:            }
        !           590: 
        !           591:            /* Actually do the compression/decompression */
        !           592:            if (do_decomp == 0) compress();
        !           593: #ifndef DEBUG
        !           594:            else                        decompress();
        !           595: #else   DEBUG
        !           596:            else if (debug == 0)        decompress();
        !           597:            else                        printcodes();
        !           598:            if (verbose)                dump_tab();
        !           599: #endif DEBUG
        !           600:            if(zcat_flg == 0) {
        !           601:                copystat(*fileptr, ofname);     /* Copy stats */
        !           602:                if(exit_stat || (!quiet))
        !           603:                        putc('\n', stderr);
        !           604:            }
        !           605:        }
        !           606:     } else {           /* Standard input */
        !           607:        if (do_decomp == 0) {
        !           608:                compress();
        !           609:                if(!quiet)
        !           610:                        putc('\n', stderr);
        !           611:        } else {
        !           612:            /* Check the magic number */
        !           613:            if (nomagic == 0) {
        !           614:                if ((getchar()!=(magic_header[0] & 0xFF))
        !           615:                 || (getchar()!=(magic_header[1] & 0xFF))) {
        !           616:                    fprintf(stderr, "stdin: not in compressed format\n");
        !           617:                    exit(1);
        !           618:                }
        !           619:                maxbits = getchar();    /* set -b from file */
        !           620:                block_compress = maxbits & BLOCK_MASK;
        !           621:                maxbits &= BIT_MASK;
        !           622:                maxmaxcode = 1 << maxbits;
        !           623:                fsize = 100000;         /* assume stdin large for USERMEM */
        !           624:                if(maxbits > BITS) {
        !           625:                        fprintf(stderr,
        !           626:                        "stdin: compressed with %d bits, can only handle %d bits\n",
        !           627:                        maxbits, BITS);
        !           628:                        exit(1);
        !           629:                }
        !           630:            }
        !           631: #ifndef DEBUG
        !           632:            decompress();
        !           633: #else   DEBUG
        !           634:            if (debug == 0)     decompress();
        !           635:            else                printcodes();
        !           636:            if (verbose)        dump_tab();
        !           637: #endif DEBUG
        !           638:        }
        !           639:     }
        !           640:     exit(exit_stat);
        !           641: }
        !           642: 
        !           643: static int offset;
        !           644: long int in_count = 1;                 /* length of input */
        !           645: long int bytes_out;                    /* length of compressed output */
        !           646: long int out_count = 0;                        /* # of codes output (for debugging) */
        !           647: 
        !           648: #define HOG_CHECK ((count_int) 2000)   /* Number of chars to read b4 check */
        !           649: #define MAX_CACHE ((count_int) 1<<BITS) /* Next line is this constant too */
        !           650: unsigned short hashcache [1<<BITS];    /* common hash short circuit cache */
        !           651: count_int cfreq [256];                 /* character counts */
        !           652: #ifndef vax
        !           653:  char chog;                            /* most common character from input */
        !           654: # define CHOG  ' '                     /* Assume space is most frequent */
        !           655: #else 
        !           656:  int chog;                             /* char arith slow on VAX */
        !           657: # define CHOG  (int) ' '               /* Assume space is most frequent */
        !           658: #endif
        !           659: int cstat_flg = 0;                     /* on after determining char hog */
        !           660: 
        !           661: /*
        !           662:  * compress stdin to stdout
        !           663:  *
        !           664:  * Algorithm:  on large machines, for maxbits <= FBITS, use fast direct table
        !           665:  * lookup on the prefix code / next character combination.  For smaller code
        !           666:  * size, use open addressing modular division double hashing (no chaining), ala
        !           667:  * Knuth vol. 3, sec. 6.4 Algorithm D, along with G. Knott's relatively-prime
        !           668:  * secondary probe.  Do block compression with an adaptive reset, whereby the
        !           669:  * code table is cleared when the compression ratio decreases, but after the
        !           670:  * table fills.  The variable-length output codes are re-sized at this point,
        !           671:  * and a special CLEAR code is generated for the decompressor.  For the
        !           672:  * megamemory version, the sparse array is cleared indirectly through a
        !           673:  * "shadow" output code history.  Late additions: for the hashing code,
        !           674:  * construct the table according to file size for noticeable speed improvement
        !           675:  * on small files.  Also detect and cache codes associated with the most
        !           676:  * common character to bypass hash calculation on these codes (a characteristic
        !           677:  * of highly-compressable raster images).  Please direct questions about this
        !           678:  * implementation to ames!jaw.
        !           679:  */
        !           680: 
        !           681: 
        !           682: compress() {
        !           683:     register long fcode;
        !           684:     register code_int i = 0;
        !           685:     register int c;
        !           686:     register code_int ent;
        !           687:     register int disp;
        !           688:     register code_int hsize_reg;
        !           689: 
        !           690: #ifndef COMPATIBLE
        !           691:     if (nomagic == 0) {
        !           692:        putchar(magic_header[0]); putchar(magic_header[1]);
        !           693:        putchar((char)(maxbits | block_compress));
        !           694:     }
        !           695: #endif COMPATIBLE
        !           696: 
        !           697:     offset = 0;
        !           698:     bytes_out = 0;
        !           699:     out_count = 0;
        !           700:     clear_flg = 0;
        !           701:     ratio = 0.0;
        !           702:     in_count = 1;
        !           703:     checkpoint = CHECK_GAP;
        !           704:     maxcode = MAXCODE(n_bits = INIT_BITS);
        !           705:     free_ent = ((block_compress) ? FIRST : 256 );
        !           706:     ent = getchar ();
        !           707: 
        !           708: #ifdef USERMEM
        !           709: if ( maxbits <= FBITS && (fsize >= 30000) ) {  /* use hashing on small files */
        !           710: 
        !           711:     while ( (c = getchar()) != (unsigned) EOF ) {
        !           712:        in_count++;
        !           713:        fcode = (long) (((long) c << maxbits) + ent);
        !           714:        if ( ftable [fcode] != 0 )              /* test for code in "string" table */
        !           715:            ent = ftable [fcode];
        !           716:        else {
        !           717:            output ( (code_int) ent );
        !           718:            out_count++;
        !           719:            ent = c;
        !           720:            if ( free_ent >= maxmaxcode ) {     
        !           721:                if ( (count_int)in_count < checkpoint || (!block_compress) ) 
        !           722:                    continue;
        !           723:                else {
        !           724:                    clear ();
        !           725:                    i = 0;
        !           726:                }
        !           727:            } else {                            /* put code in table */
        !           728:                ftable [fcode] = (short) free_ent++;
        !           729:                fcodemem [i++] = fcode;         /* memorize for block compression */
        !           730:            }
        !           731:        }
        !           732:     }
        !           733:     goto fin;
        !           734: }
        !           735: #endif USERMEM
        !           736: 
        !           737:     chog = CHOG;               /* assumed character for the hog */
        !           738:     cstat_flg = 0;
        !           739:     hsize_reg = hsize;
        !           740:     cl_hash(hsize_reg);                /* clear hash tables */
        !           741: 
        !           742:     while ( (c = getchar()) != (unsigned) EOF ) {
        !           743:        in_count++;
        !           744:        if ( cstat_flg == 0 ) {
        !           745:            cfreq [c]++;        /* gather frequencies at start of input */
        !           746:            if ( (count_int)in_count >  HOG_CHECK ) {
        !           747:                cstat_flg = 1;
        !           748:                chog = hogtally();      /* compute char hog */
        !           749:                if(chog != CHOG)        /* fixup for wrong assumption */
        !           750:                    creset( (count_int) free_ent );
        !           751:            }
        !           752:        }
        !           753:        if ( c == chog )
        !           754:            if ( (i = hashcache [ent]) ) {      /* cache -> code */
        !           755:                ent = i;
        !           756:                continue;
        !           757:            }
        !           758:        fcode = (long) (((long) c << maxbits) + ent);
        !           759: #ifdef SHORT_INT
        !           760:        i = (((c + 12347) * ent) & 077777) % HSIZE;     /* avoid 'lrem' call */
        !           761: #else !SHORT_INT
        !           762:        i = fcode % hsize_reg;                  /* division hashing */
        !           763: #endif SHORT_INT
        !           764: 
        !           765:        if ( htab [i] == fcode ) {
        !           766:            ent = codetab [i];
        !           767:            continue;
        !           768:        } else if ( (long)htab [i] < 0 )        /* empty slot */
        !           769:            goto nomatch;
        !           770:        disp = hsize_reg - i;           /* secondary hash (G. Knott) */
        !           771:        if ( i == 0 )
        !           772:            disp = 1;
        !           773: probe:
        !           774:        if ( (i -= disp) < 0 )
        !           775:            i += hsize_reg;
        !           776: 
        !           777:        if ( htab [i] == fcode ) {
        !           778:            ent = codetab [i];
        !           779:            continue;
        !           780:        }
        !           781:        if ( (long)htab [i] > 0 ) 
        !           782:            goto probe;
        !           783: nomatch:
        !           784:        output ( (code_int) ent );
        !           785:        out_count++;
        !           786: #ifdef interdata
        !           787:        if ( (unsigned) free_ent < (unsigned) maxmaxcode) {
        !           788: #else
        !           789:        if ( free_ent < maxmaxcode ) {
        !           790: #endif
        !           791:            if ( c == chog )            /* code -> cache */
        !           792:                hashcache [ent] = free_ent;
        !           793:                                        /* code -> hashtable */
        !           794:            codetab [i] = free_ent++;
        !           795:            htab [i] = fcode;
        !           796:        }
        !           797:        else if ( (count_int)in_count >= checkpoint && block_compress )
        !           798:            clear ();
        !           799:        ent = c;
        !           800:     }
        !           801: fin:
        !           802:     /*
        !           803:      * Put out the final code.
        !           804:      */
        !           805:     output( (code_int)ent );
        !           806:     out_count++;
        !           807:     output( (code_int)-1 );
        !           808: 
        !           809:     /*
        !           810:      * Print out stats on stderr
        !           811:      */
        !           812:     if(zcat_flg == 0 && !quiet) {
        !           813: #ifdef DEBUG
        !           814:        fprintf( stderr,
        !           815:        "%ld chars in, %ld codes (%ld bytes) out, compression factor %g\n",
        !           816:                in_count, out_count, bytes_out,
        !           817:                (double)in_count / (double)bytes_out );
        !           818:        fprintf( stderr, "\tCompression as in compact: %5.2f%%\n",
        !           819:                100.0 * ( in_count - bytes_out ) / (double) in_count );
        !           820:        fprintf( stderr, "\tLargest code was %d (%d bits)\n", free_ent - 1, n_bits );
        !           821: #else DEBUG
        !           822:        fprintf( stderr, "Compression: %5.2f%%",
        !           823:                100.0 * ( in_count - bytes_out ) / (double) in_count );
        !           824: #endif DEBUG
        !           825:     }
        !           826:     if(bytes_out > in_count)   /* exit(2) if no savings */
        !           827:        exit_stat = 2;
        !           828:     return;
        !           829: }
        !           830: 
        !           831: /*****************************************************************
        !           832:  * TAG( output )
        !           833:  *
        !           834:  * Output the given code.
        !           835:  * Inputs:
        !           836:  *     code:   A n_bits-bit integer.  If == -1, then EOF.  This assumes
        !           837:  *             that n_bits =< (long)wordsize - 1.
        !           838:  * Outputs:
        !           839:  *     Outputs code to the file.
        !           840:  * Assumptions:
        !           841:  *     Chars are 8 bits long.
        !           842:  * Algorithm:
        !           843:  *     Maintain a BITS character long buffer (so that 8 codes will
        !           844:  * fit in it exactly).  Use the VAX insv instruction to insert each
        !           845:  * code in turn.  When the buffer fills up empty it and start over.
        !           846:  */
        !           847: 
        !           848: static char buf[BITS];
        !           849: 
        !           850: #ifndef vax
        !           851: char_type lmask[9] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
        !           852: char_type rmask[9] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
        !           853: #endif !vax
        !           854: 
        !           855: output( code )
        !           856: code_int  code;
        !           857: {
        !           858: #ifdef DEBUG
        !           859:     static int col = 0;
        !           860: #endif DEBUG
        !           861: 
        !           862:     /*
        !           863:      * On the VAX, it is important to have the register declarations
        !           864:      * in exactly the order given, or the asm will break.
        !           865:      */
        !           866:     register int r_off = offset, bits= n_bits;
        !           867:     register char * bp = buf;
        !           868: 
        !           869:     if ( code >= 0 ) {
        !           870: #ifdef DEBUG
        !           871:        if ( verbose )
        !           872:            fprintf( stderr, "%5d%c", code,
        !           873:                    (col+=6) >= 74 ? (col = 0, '\n') : ' ' );
        !           874: #endif DEBUG
        !           875: #ifdef vax
        !           876:        /* VAX DEPENDENT!! Implementation on other machines may be
        !           877:         * difficult.
        !           878:         *
        !           879:         * Translation: Insert BITS bits from the argument starting at
        !           880:         * offset bits from the beginning of buf.
        !           881:         */
        !           882:        0;      /* C compiler bug ?? */
        !           883:        asm( "insv      4(ap),r11,r10,(r9)" );
        !           884: #else not a vax
        !           885: /* WARNING: byte/bit numbering on the vax is simulated by the following code
        !           886: */
        !           887:        /*
        !           888:         * Get to the first byte.
        !           889:         */
        !           890:        bp += (r_off >> 3);
        !           891:        r_off &= 7;
        !           892:        /*
        !           893:         * Since code is always >= 8 bits, only need to mask the first
        !           894:         * hunk on the left.
        !           895:         */
        !           896:        *bp = (*bp & rmask[r_off]) | (code << r_off) & lmask[r_off];
        !           897:        bp++;
        !           898:        bits -= (8 - r_off);
        !           899:        code >>= 8 - r_off;
        !           900:        /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
        !           901:        if ( bits >= 8 ) {
        !           902:            *bp++ = code;
        !           903:            code >>= 8;
        !           904:            bits -= 8;
        !           905:        }
        !           906:        /* Last bits. */
        !           907:        if(bits)
        !           908:            *bp = code;
        !           909: #endif vax
        !           910:        offset += n_bits;
        !           911:        if ( offset == (n_bits << 3) ) {
        !           912:            bp = buf;
        !           913:            bits = n_bits;
        !           914:            bytes_out += bits;
        !           915:            do
        !           916:                putchar(*bp++);
        !           917:            while(--bits);
        !           918:            if (ferror(stdout))
        !           919:                writeerr();
        !           920:            offset = 0;
        !           921:        }
        !           922: 
        !           923:        /*
        !           924:         * If the next entry is going to be too big for the code size,
        !           925:         * then increase it, if possible.
        !           926:         */
        !           927:        if ( free_ent > maxcode || (clear_flg > 0)) {
        !           928:            /*
        !           929:             * Write the whole buffer, because the input side won't
        !           930:             * discover the size increase until after it has read it.
        !           931:             */
        !           932:            if ( offset > 0 ) {
        !           933:                if( fwrite( buf, 1, n_bits, stdout ) != n_bits)
        !           934:                        writeerr();
        !           935:                bytes_out += n_bits;
        !           936:            }
        !           937:            offset = 0;
        !           938: 
        !           939:            if ( clear_flg ) {
        !           940:                maxcode = MAXCODE (n_bits = INIT_BITS);
        !           941:                clear_flg = 0;
        !           942:            } else {
        !           943:                n_bits++;
        !           944:                if ( n_bits == maxbits )
        !           945:                    maxcode = maxmaxcode;
        !           946:                else
        !           947:                    maxcode = MAXCODE(n_bits);
        !           948:            }
        !           949: #ifdef DEBUG
        !           950:            if ( debug ) {
        !           951:                fprintf( stderr, "\nChange to %d bits\n", n_bits );
        !           952:                col = 0;
        !           953:            }
        !           954: #endif DEBUG
        !           955:        }
        !           956:     } else {
        !           957:        /*
        !           958:         * At EOF, write the rest of the buffer.
        !           959:         */
        !           960:        if ( offset > 0 )
        !           961:            fwrite( buf, 1, (offset + 7) / 8, stdout );
        !           962:        bytes_out += (offset + 7) / 8;
        !           963:        offset = 0;
        !           964:        fflush( stdout );
        !           965: #ifdef DEBUG
        !           966:        if ( verbose )
        !           967:            fprintf( stderr, "\n" );
        !           968: #endif DEBUG
        !           969:        if( ferror( stdout ) )
        !           970:                writeerr();
        !           971:     }
        !           972: }
        !           973: 
        !           974: decompress() {
        !           975:     register int stack_top = MAXSTACK;
        !           976:     register code_int code, oldcode, incode;
        !           977:     register int finchar;
        !           978:     char stack[MAXSTACK];
        !           979: 
        !           980:     /*
        !           981:      * As above, initialize the first 256 entries in the table.
        !           982:      */
        !           983:     maxcode = MAXCODE(n_bits = INIT_BITS);
        !           984:     for ( code = 255; code >= 0; code-- ) {
        !           985:        tab_prefix[code] = 0;
        !           986:        tab_suffix[code] = (char_type)code;
        !           987:     }
        !           988:     free_ent = ((block_compress) ? FIRST : 256 );
        !           989: 
        !           990:     finchar = oldcode = getcode();
        !           991:     putchar( (char)finchar );          /* first code must be 8 bits = char */
        !           992: 
        !           993:     while ( (code = getcode()) != -1 ) {
        !           994: 
        !           995:        if ( (code == CLEAR) && block_compress ) {
        !           996:            for ( code = 255; code > 0; code -= 4 ) {
        !           997:                tab_prefix [code-3] = 0;
        !           998:                tab_prefix [code-2] = 0;
        !           999:                tab_prefix [code-1] = 0;
        !          1000:                tab_prefix [code] = 0;
        !          1001:            }
        !          1002:            clear_flg = 1;
        !          1003:            free_ent = FIRST - 1;
        !          1004:            if ( (code = getcode ()) == -1 )    /* O, untimely death! */
        !          1005:                break;
        !          1006:        }
        !          1007:        incode = code;
        !          1008:        /*
        !          1009:         * Special case for KwKwK string.
        !          1010:         */
        !          1011:        if ( code >= free_ent ) {
        !          1012:            stack[--stack_top] = finchar;
        !          1013:            code = oldcode;
        !          1014:        }
        !          1015: 
        !          1016:        /*
        !          1017:         * Generate output characters in reverse order
        !          1018:         */
        !          1019: #ifdef interdata
        !          1020:        while ( ((unsigned long)code) >= ((unsigned long)256) ) {
        !          1021: #else !interdata
        !          1022:        while ( code >= 256 ) {
        !          1023: #endif interdata
        !          1024:            stack[--stack_top] = tab_suffix[code];
        !          1025:            code = tab_prefix[code];
        !          1026:        }
        !          1027:        stack[--stack_top] = finchar = tab_suffix[code];
        !          1028: 
        !          1029:        /*
        !          1030:         * And put them out in forward order
        !          1031:         */
        !          1032:        for ( ; stack_top < MAXSTACK; stack_top++ )
        !          1033:                putchar(stack[stack_top]);
        !          1034:        if (ferror(stdout))
        !          1035:                writeerr ( );
        !          1036:        stack_top = MAXSTACK;
        !          1037: 
        !          1038:        /*
        !          1039:         * Generate the new entry.
        !          1040:         */
        !          1041:        if ( (code=free_ent) < maxmaxcode ) {
        !          1042:            tab_prefix[code] = (unsigned short)oldcode;
        !          1043:            tab_suffix[code] = finchar;
        !          1044:            free_ent = code+1;
        !          1045:        } 
        !          1046:        /*
        !          1047:         * Remember previous code.
        !          1048:         */
        !          1049:        oldcode = incode;
        !          1050:     }
        !          1051:     fflush( stdout );
        !          1052:     if(ferror(stdout))
        !          1053:        writeerr();
        !          1054: }
        !          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  NO_UCHAR
        !          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  NO_UCHAR
        !          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.  Mostly 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: dump_tab()     /* dump string table */
        !          1181: {
        !          1182:     register int i;
        !          1183:     register ent;
        !          1184:     char stack[4 * MAXSTACK];  /* \nnn makes it 4 times bigger */
        !          1185:     int stack_top = 4 * MAXSTACK;
        !          1186: 
        !          1187:     for ( i = 0; i < free_ent; i++ ) {
        !          1188:        ent = i;
        !          1189:        if ( isascii(tab_suffix[ent]) && isprint(tab_suffix[ent]) )
        !          1190:            fprintf( stderr, "%5d: %5d/'%c'  \"",
        !          1191:                        ent, tab_prefix[ent], tab_suffix[ent] );
        !          1192:        else
        !          1193:            fprintf( stderr, "%5d: %5d/\\%03o \"",
        !          1194:                        ent, tab_prefix[ent], tab_suffix[ent] );
        !          1195:        stack[--stack_top] = '\n';
        !          1196:        stack[--stack_top] = '"';
        !          1197:        for ( ; ent != NULL;
        !          1198:                ent = (ent >= FIRST ? tab_prefix[ent] : NULL) ) {
        !          1199:            if ( isascii(tab_suffix[ent]) && isprint(tab_suffix[ent]) )
        !          1200:                stack[--stack_top] = tab_suffix[ent];
        !          1201:            else {
        !          1202:                switch( tab_suffix[ent] ) {
        !          1203:                case '\n': stack[--stack_top] = 'n'; break;
        !          1204:                case '\t': stack[--stack_top] = 't'; break;
        !          1205:                case '\b': stack[--stack_top] = 'b'; break;
        !          1206:                case '\f': stack[--stack_top] = 'f'; break;
        !          1207:                case '\r': stack[--stack_top] = 'r'; break;
        !          1208:                default:
        !          1209:                    stack[--stack_top] = '0' + tab_suffix[ent] % 8;
        !          1210:                    stack[--stack_top] = '0' + (tab_suffix[ent] / 8) % 8;
        !          1211:                    stack[--stack_top] = '0' + tab_suffix[ent] / 64;
        !          1212:                    break;
        !          1213:                }
        !          1214:                stack[--stack_top] = '\\';
        !          1215:            }
        !          1216:        }
        !          1217:        fwrite( &stack[stack_top], 1, 4 * MAXSTACK - stack_top, stderr );
        !          1218:        stack_top = 4 * MAXSTACK;
        !          1219:     }
        !          1220: }
        !          1221: #endif DEBUG
        !          1222: 
        !          1223: /*****************************************************************
        !          1224:  * TAG( writeerr )
        !          1225:  *
        !          1226:  * Exits with a message.  We only check for write errors often enough
        !          1227:  * to avoid a lot of "file system full" messages, not on every write.
        !          1228:  * ferror() check after fflush will catch any others (I trust).
        !          1229:  *
        !          1230:  */
        !          1231: 
        !          1232: writeerr()
        !          1233: {
        !          1234:     perror ( ofname );
        !          1235:     unlink ( ofname );
        !          1236:     exit ( 1 );
        !          1237: }
        !          1238: 
        !          1239: copystat(ifname, ofname)
        !          1240: char *ifname, *ofname;
        !          1241: {
        !          1242:     struct stat statbuf;
        !          1243:     int mode;
        !          1244:     time_t timep[2];
        !          1245: 
        !          1246:     fclose(stdout);
        !          1247:     if (stat(ifname, &statbuf)) {              /* Get stat on input file */
        !          1248:        perror(ifname);
        !          1249:        return;
        !          1250:     }
        !          1251:     if ((statbuf.st_mode & S_IFMT/*0170000*/) != S_IFREG/*0100000*/) {
        !          1252:        if(quiet)
        !          1253:                fprintf(stderr, "%s: ", ifname);
        !          1254:        fprintf(stderr, " -- not a regular file: unchanged");
        !          1255:        exit_stat = 1;
        !          1256:     } else if (statbuf.st_nlink > 1) {
        !          1257:        if(quiet)
        !          1258:                fprintf(stderr, "%s: ", ifname);
        !          1259:        fprintf(stderr, " -- has %d other links: unchanged",
        !          1260:                statbuf.st_nlink - 1);
        !          1261:        exit_stat = 1;
        !          1262:     } else if (exit_stat == 2 && (!force)) { /* No compression: remove file.Z */
        !          1263:        fprintf(stderr, " -- file unchanged");
        !          1264:     } else {                   /* ***** Successful Compression ***** */
        !          1265:        exit_stat = 0;
        !          1266:        mode = statbuf.st_mode & 07777;
        !          1267:        if (chmod(ofname, mode))                /* Copy modes */
        !          1268:            perror(ofname);
        !          1269:        chown(ofname, statbuf.st_uid, statbuf.st_gid);  /* Copy ownership */
        !          1270:        timep[0] = statbuf.st_atime;
        !          1271:        timep[1] = statbuf.st_mtime;
        !          1272:        utime(ofname, timep);   /* Update last accessed and modified times */
        !          1273:        if (unlink(ifname))     /* Remove input file */
        !          1274:            perror(ifname);
        !          1275:        if(!quiet)
        !          1276:                fprintf(stderr, " -- replaced with %s", ofname);
        !          1277:        return;         /* Successful return */
        !          1278:     }
        !          1279: 
        !          1280:     /* Unsuccessful return -- one of the tests failed */
        !          1281:     if (unlink(ofname))
        !          1282:        perror(ofname);
        !          1283: }
        !          1284: /*
        !          1285:  * This routine returns 1 if we are running in the foreground and stderr
        !          1286:  * is a tty.
        !          1287:  */
        !          1288: foreground()
        !          1289: {
        !          1290:        if(bgnd_flag) { /* background? */
        !          1291:                return(0);
        !          1292:        } else {                        /* foreground */
        !          1293:                if(isatty(2)) {         /* and stderr is a tty */
        !          1294:                        return(1);
        !          1295:                } else {
        !          1296:                        return(0);
        !          1297:                }
        !          1298:        }
        !          1299: }
        !          1300: 
        !          1301: onintr ( )
        !          1302: {
        !          1303:     unlink ( ofname );
        !          1304:     exit ( 1 );
        !          1305: }
        !          1306: 
        !          1307: clear ()               /* table clear for block compress */
        !          1308: {
        !          1309:     register code_int i;
        !          1310:     register count_int *p, *endp;
        !          1311:     register unsigned short *q;
        !          1312: 
        !          1313: #ifdef DEBUG
        !          1314:        if(debug)
        !          1315:                fprintf ( stderr, "count: %ld ratio: %f\n", in_count,
        !          1316:                (double) in_count / (double) bytes_out );
        !          1317: #endif DEBUG
        !          1318: 
        !          1319:     checkpoint = in_count + CHECK_GAP;
        !          1320:     if ( (double) in_count / (double) bytes_out > ratio )
        !          1321:        ratio = (double) in_count / (double) bytes_out;
        !          1322:     else {
        !          1323:        ratio = 0.0;
        !          1324: #ifdef USERMEM
        !          1325:        if ( maxbits <= FBITS )                 /* sparse array clear */
        !          1326:            for ( i = (1 << maxbits) - 1; i >= 0; i-- )
        !          1327:                ftable [fcodemem [i]] = 0;      /* indirect thru "shadow" */
        !          1328:        else 
        !          1329: #endif USERMEM                                 /* hash table clear */
        !          1330:        {
        !          1331:            endp = &htab [hsize];
        !          1332:            for ( p = &htab [0], q = &codetab [0]; p < endp; ) {
        !          1333:                *p++ = -1;
        !          1334:                *q++ = 0;
        !          1335:            }
        !          1336:            creset ( MAX_CACHE );
        !          1337:        }
        !          1338:        free_ent = FIRST;
        !          1339:        clear_flg = 1;
        !          1340:        output ( (code_int) CLEAR );
        !          1341: #ifdef DEBUG
        !          1342:        if(debug)
        !          1343:                fprintf ( stderr, "clear\n" );
        !          1344: #endif DEBUG
        !          1345:     }
        !          1346: }
        !          1347: 
        !          1348: creset ( n )   /* clear hash cache */
        !          1349:     register count_int n;      /* clear at least this many entries */
        !          1350: {
        !          1351:     register count_int i;
        !          1352:     register unsigned short *hash_p;
        !          1353:     register unsigned short zero = 0;
        !          1354:     static int nfiles = 0;
        !          1355: 
        !          1356:     if ( nfiles++ == 0 )       /* No clear needed if first time */
        !          1357:        return;
        !          1358:     n = (n+15) & (-16);
        !          1359:     hash_p = hashcache + n;
        !          1360:     for ( i = n; i > 0; i -=16 ) {
        !          1361:        *(hash_p-16) = zero;
        !          1362:        *(hash_p-15) = zero;
        !          1363:        *(hash_p-14) = zero;
        !          1364:        *(hash_p-13) = zero;
        !          1365:        *(hash_p-12) = zero;
        !          1366:        *(hash_p-11) = zero;
        !          1367:        *(hash_p-10) = zero;
        !          1368:        *(hash_p-9) = zero;
        !          1369:        *(hash_p-8) = zero;
        !          1370:        *(hash_p-7) = zero;
        !          1371:        *(hash_p-6) = zero;
        !          1372:        *(hash_p-5) = zero;
        !          1373:        *(hash_p-4) = zero;
        !          1374:        *(hash_p-3) = zero;
        !          1375:        *(hash_p-2) = zero;
        !          1376:        *(hash_p-1) = zero;
        !          1377:        hash_p -= 16;
        !          1378:     }
        !          1379: }
        !          1380: 
        !          1381: hogtally ()    /* compute character code hog */
        !          1382: {
        !          1383:     register int i, most;
        !          1384: 
        !          1385:     for ( i = most = 0; i < 256; i++ )
        !          1386:        if ( cfreq [i] >= cfreq [most] )
        !          1387:            most = i;
        !          1388:     return ( most );
        !          1389: }
        !          1390: 
        !          1391: cl_hash(hsize)
        !          1392:        register int hsize;
        !          1393: {
        !          1394:        register count_int *htab_p = htab+hsize;
        !          1395:        register int i;
        !          1396:        register long m1 = -1;
        !          1397: 
        !          1398:        /* clear hashcache */
        !          1399: #define        min(a,b)        ((a>b) ? b : a)
        !          1400:        creset( min((count_int)hsize, MAX_CACHE) );
        !          1401: 
        !          1402:        i = hsize - 16;
        !          1403:        do {
        !          1404:                *(htab_p-16) = m1;
        !          1405:                *(htab_p-15) = m1;
        !          1406:                *(htab_p-14) = m1;
        !          1407:                *(htab_p-13) = m1;
        !          1408:                *(htab_p-12) = m1;
        !          1409:                *(htab_p-11) = m1;
        !          1410:                *(htab_p-10) = m1;
        !          1411:                *(htab_p-9) = m1;
        !          1412:                *(htab_p-8) = m1;
        !          1413:                *(htab_p-7) = m1;
        !          1414:                *(htab_p-6) = m1;
        !          1415:                *(htab_p-5) = m1;
        !          1416:                *(htab_p-4) = m1;
        !          1417:                *(htab_p-3) = m1;
        !          1418:                *(htab_p-2) = m1;
        !          1419:                *(htab_p-1) = m1;
        !          1420:                htab_p -= 16;
        !          1421:        } while ((i -= 16) >= 0);
        !          1422:        for ( i += 16; i > 0; i-- )
        !          1423:                *--htab_p = m1;
        !          1424: }

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