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#include <stdarg.h>

#include "support.h"

#define BYTES_TO_COMPRESS 1000

/*

 * Compress - data compression program

 */

#define min(a,b)        ((a>b) ? b : a)

/*

 * machine variants which require cc -Dmachine:  pdp11, z8000, pcxt

 */

/*

 * Set USERMEM to the maximum amount of physical user memory available

 * in bytes.  USERMEM is used to determine the maximum BITS that can be used

 * for compression.

 *

 * SACREDMEM is the amount of physical memory saved for others; compress

 * will hog the rest.

 */

#ifndef SACREDMEM

#define SACREDMEM       0

#endif

/* #ifndef USERMEM */

#define USERMEM         60000   /* default user memory */

/* #endif */

#ifdef interdata                /* (Perkin-Elmer) */

#define SIGNED_COMPARE_SLOW     /* signed compare is slower than unsigned */

#endif

#ifdef USERMEM

# if USERMEM >= (433484+SACREDMEM)

#  define PBITS 16

# else

#  if USERMEM >= (229600+SACREDMEM)

#   define PBITS        15

#  else

#   if USERMEM >= (127536+SACREDMEM)

#    define PBITS       14

#   else

#    if USERMEM >= (73464+SACREDMEM)

#     define PBITS      13

#    else

#     define PBITS      12

#    endif

#   endif

#  endif

# endif

# undef USERMEM

#endif /* USERMEM */

#ifdef PBITS            /* Preferred BITS for this memory size */

# ifndef BITS

#  define BITS PBITS

# endif /* BITS */

#endif /* PBITS */

#if BITS == 16

# define HSIZE  69001           /* 95% occupancy */

#endif

#if BITS == 15

# define HSIZE  35023           /* 94% occupancy */

#endif

#if BITS == 14

# define HSIZE  18013           /* 91% occupancy */

#endif

#if BITS == 13

# define HSIZE  9001            /* 91% occupancy */

#endif

#if BITS <= 12

# define HSIZE  5003            /* 80% occupancy */

#endif

/*

 * a code_int must be able to hold 2**BITS values of type int, and also -1

 */

#if BITS > 15

typedef long int        code_int;

#else

typedef int             code_int;

#endif

#ifdef SIGNED_COMPARE_SLOW

typedef unsigned long int count_int;

typedef unsigned short int count_short;

#else

typedef long int          count_int;

#endif

#ifdef NO_UCHAR

 typedef char   char_type;

#else

 typedef        unsigned char   char_type;

#endif /* UCHAR */

char_type magic_header[] = { "\037\235" };      /* 1F 9D */

/* Defines for third byte of header */

#define BIT_MASK        0x1f

#define BLOCK_MASK      0x80

/* Masks 0x40 and 0x20 are free.  I think 0x20 should mean that there is

   a fourth header byte (for expansion).

*/

#define INIT_BITS 9                     /* initial number of bits/code */

/*

 * compress.c - File compression ala IEEE Computer, June 1984.

 *

 * Authors:     Spencer W. Thomas       (decvax!harpo!utah-cs!utah-gr!thomas)

 *              Jim McKie               (decvax!mcvax!jim)

 *              Steve Davies            (decvax!vax135!petsd!peora!srd)

 *              Ken Turkowski           (decvax!decwrl!turtlevax!ken)

 *              James A. Woods          (decvax!ihnp4!ames!jaw)

 *              Joe Orost               (decvax!vax135!petsd!joe)

 *

 */

#if i386

#include <stdio.h>

#include <stdio.h>

#include <ctype.h>

#include <signal.h>

#include <sys/types.h>

#include <sys/stat.h>

#endif

#define ARGVAL() (*++(*argv) || (--argc && *++argv))

int n_bits;                             /* number of bits/code */

int maxbits = BITS;                     /* user settable max # bits/code */

code_int maxcode;                       /* maximum code, given n_bits */

code_int maxmaxcode = 1L << BITS;       /* should NEVER generate this code */

#ifdef COMPATIBLE               /* But wrong! */

# define MAXCODE(n_bits)        (1L << (n_bits) - 1)

#else

# define MAXCODE(n_bits)        ((1L << (n_bits)) - 1)

#endif /* COMPATIBLE */

# ifdef sel

/* support gould base register problems */

/*NOBASE*/

count_int htab [HSIZE];

unsigned short codetab [HSIZE];

/*NOBASE*/

# else /* !gould */

count_int htab [HSIZE];

unsigned short codetab [HSIZE];

# endif /* !gould */

#define htabof(i)       htab[i]

#define codetabof(i)    codetab[i]

code_int hsize = HSIZE;                 /* for dynamic table sizing */

count_int fsize;

/*

 * To save much memory, we overlay the table used by compress() with those

 * used by decompress().  The tab_prefix table is the same size and type

 * as the codetab.  The tab_suffix table needs 2**BITS characters.  We

 * get this from the beginning of htab.  The output stack uses the rest

 * of htab, and contains characters.  There is plenty of room for any

 * possible stack (stack used to be 8000 characters).

 */

#define tab_prefixof(i) codetabof(i)

#ifdef XENIX_16

# define tab_suffixof(i)        ((char_type *)htab[(i)>>15])[(i) & 0x7fff]

# define de_stack               ((char_type *)(htab2))

#else   /* Normal machine */

# define tab_suffixof(i)        ((char_type *)(htab))[i]

# define de_stack               ((char_type *)&tab_suffixof(1<<BITS))

#endif  /* XENIX_16 */

code_int free_ent = 0;                   /* first unused entry */

int exit_stat = 0;

code_int getcode();

int nomagic = 0; /* Use a 3-byte magic number header, unless old file */

int zcat_flg = 0;        /* Write output on stdout, suppress messages */

int quiet = 1;          /* don't tell me about compression */

/*

 * block compression parameters -- after all codes are used up,

 * and compression rate changes, start over.

 */

int block_compress = BLOCK_MASK;

int clear_flg = 0;

long int ratio = 0;

#define CHECK_GAP 10000 /* ratio check interval */

count_int checkpoint = CHECK_GAP;

/*

 * the next two codes should not be changed lightly, as they must not

 * lie within the contiguous general code space.

 */

#define FIRST   257     /* first free entry */

#define CLEAR   256     /* table clear output code */

int force = 0;

char ofname [100];

int (*bgnd_flag)();

/* reset code table */

void cl_hash(register count_int hsize);

/* table clear for block compress */

void cl_block ();

void output(code_int  code);

int do_decomp = 0;

static int offset;

long int in_count = 1;                  /* length of input */

long int bytes_out;                     /* length of compressed output */

long int out_count = 0;                  /* # of codes output (for debugging) */

/*

 * compress stdin to stdout

 *

 * Algorithm:  use open addressing double hashing (no chaining) on the

 * prefix code / next character combination.  We do a variant of Knuth's

 * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime

 * secondary probe.  Here, the modular division first probe is gives way

 * to a faster exclusive-or manipulation.  Also do block compression with

 * an adaptive reset, whereby the code table is cleared when the compression

 * ratio decreases, but after the table fills.  The variable-length output

 * codes are re-sized at this point, and a special CLEAR code is generated

 * for the decompressor.  Late addition:  construct the table according to

 * file size for noticeable speed improvement on small files.  Please direct

 * questions about this implementation to ames!jaw.

 */

int main() {

    register long fcode;

    register code_int i = 0;

    register int c;

    register code_int ent;

#ifdef XENIX_16

    register code_int disp;

#else   /* Normal machine */

    register int disp;

#endif

    register code_int hsize_reg;

    register int hshift;

#ifndef COMPATIBLE

    if (nomagic == 0) {

        /* putchar(magic_header[0]); putchar(magic_header[1]);

        putchar((char)(maxbits | block_compress)); */

    }

#endif /* COMPATIBLE */

    offset = 0;

    bytes_out = 3;              /* includes 3-byte header mojo */

    out_count = 0;

    clear_flg = 0;

    ratio = 0;

    in_count = 1;

    printf("main: bytes_out %d... hsize %d\n", (int)bytes_out, (int)hsize);

    checkpoint = CHECK_GAP;

    maxcode = MAXCODE(n_bits = INIT_BITS);

    free_ent = ((block_compress) ? FIRST : 256 );

    ent = '\0'; /* getchar (); */

    hshift = 0;

    for ( fcode = (long) hsize;  fcode < 65536L; fcode *= 2L )

        hshift++;

    hshift = 8 - hshift;                /* set hash code range bound */

    printf("main: hshift %d...\n", hshift);

    hsize_reg = hsize;

    cl_hash( (count_int) hsize_reg);            /* clear hash table */

/*#ifdef SIGNED_COMPARE_SLOW

    while ( (c = getchar()) != (unsigned) EOF ) {

#else

    while ( (c = getchar()) != EOF ) {

#endif*/

    printf("main: bytes_out %d...\n", (int)bytes_out);

    printf("main: hsize_reg %d...\n", (int)hsize_reg);

    printf("main: before compress %d...\n", (int)in_count);

    while (in_count < BYTES_TO_COMPRESS) {

        c = in_count % 255;

        printf("main: compressing %d...\n", (int)in_count);

        in_count++;

        fcode = (long) (((long) c << maxbits) + ent);

        i = (((long)c << hshift) ^ ent);        /* xor hashing */

        if ( htabof (i) == fcode ) {

            ent = codetabof (i);

            continue;

        } else if ( (long)htabof (i) < 0 )       /* empty slot */

            goto nomatch;

        disp = hsize_reg - i;           /* secondary hash (after G. Knott) */

        if ( i == 0 )

            disp = 1;

probe:

        if ( (i -= disp) < 0 )

            i += hsize_reg;

        if ( htabof (i) == fcode ) {

            ent = codetabof (i);

            continue;

        }

        if ( (long)htabof (i) > 0 )

            goto probe;

nomatch:

        output ( (code_int) ent );

        out_count++;

        ent = c;

#ifdef SIGNED_COMPARE_SLOW

        if ( (unsigned) free_ent < (unsigned) maxmaxcode) {

#else

        if ( free_ent < maxmaxcode ) {

#endif

            codetabof (i) = free_ent++; /* code -> hashtable */

            htabof (i) = fcode;

        }

        else if ( (count_int)in_count >= checkpoint && block_compress )

            cl_block ();

    }

    /*

     * Put out the final code.

     */

    printf("main: output...\n");

    output( (code_int)ent );

    out_count++;

    output( (code_int)-1 );

    if(bytes_out > in_count)    /* exit(2) if no savings */

        exit_stat = 2;

    printf("main: end...\n");

    report (0xdeaddead);

    return 0;

}

/*****************************************************************

 * TAG( output )

 *

 * Output the given code.

 * Inputs:

 *      code:   A n_bits-bit integer.  If == -1, then EOF.  This assumes

 *              that n_bits =< (long)wordsize - 1.

 * Outputs:

 *      Outputs code to the file.

 * Assumptions:

 *      Chars are 8 bits long.

 * Algorithm:

 *      Maintain a BITS character long buffer (so that 8 codes will

 * fit in it exactly).  Use the VAX insv instruction to insert each

 * code in turn.  When the buffer fills up empty it and start over.

 */

static char buf[BITS];

#ifndef vax

char_type lmask[9] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};

char_type rmask[9] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};

#endif /* vax */

void output( code )

code_int  code;

{

    /*

     * On the VAX, it is important to have the register declarations

     * in exactly the order given, or the asm will break.

     */

    register int r_off = offset, bits= n_bits;

    register char * bp = buf;

    if ( code >= 0 ) {

#ifdef vax

        /* VAX DEPENDENT!! Implementation on other machines is below.

         *

         * Translation: Insert BITS bits from the argument starting at

         * offset bits from the beginning of buf.

         */

        0;       /* Work around for pcc -O bug with asm and if stmt */

        asm( "insv      4(ap),r11,r10,(r9)" );

#else /* not a vax */

/*

 * byte/bit numbering on the VAX is simulated by the following code

 */

        /*

         * Get to the first byte.

         */

        bp += (r_off >> 3);

        r_off &= 7;

        /*

         * Since code is always >= 8 bits, only need to mask the first

         * hunk on the left.

         */

        *bp = (*bp & rmask[r_off]) | ((code << r_off) & lmask[r_off]);

        bp++;

        bits -= (8 - r_off);

        code >>= 8 - r_off;

        /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */

        if ( bits >= 8 ) {

            *bp++ = code;

            code >>= 8;

            bits -= 8;

        }

        /* Last bits. */

        if(bits)

            *bp = code;

#endif /* vax */

        offset += n_bits;

        if ( offset == (n_bits << 3) ) {

            bp = buf;

            bits = n_bits;

            bytes_out += bits;

        /*    do

                putchar(*bp++); */

            while(--bits);

            offset = 0;

        }

        /*

         * If the next entry is going to be too big for the code size,

         * then increase it, if possible.

         */

        if ( free_ent > maxcode || (clear_flg > 0))

        {

            /*

             * Write the whole buffer, because the input side won't

             * discover the size increase until after it has read it.

             */

            if ( offset > 0 ) {

                /* if( fwrite( buf, 1, n_bits, stdout ) != n_bits)

                        writeerr(); */

                bytes_out += n_bits;

            }

            offset = 0;

            if ( clear_flg ) {

                maxcode = MAXCODE (n_bits = INIT_BITS);

                clear_flg = 0;

            }

            else {

                n_bits++;

                if ( n_bits == maxbits )

                    maxcode = maxmaxcode;

                else

                    maxcode = MAXCODE(n_bits);

            }

        }

    } else {

        /*

         * At EOF, write the rest of the buffer.

         */

        /* if ( offset > 0 )

            fwrite( buf, 1, (offset + 7) / 8, stdout ); */

        bytes_out += (offset + 7) / 8;

        offset = 0;

        /* fflush( stdout ); */

        /* if( ferror( stdout ) )

                writeerr(); */

    }

}

/*

 * Decompress stdin to stdout.  This routine adapts to the codes in the

 * file building the "string" table on-the-fly; requiring no table to

 * be stored in the compressed file.  The tables used herein are shared

 * with those of the compress() routine.  See the definitions above.

 */

void decompress() {

    register char_type *stackp;

    register int finchar;

    register code_int code, oldcode, incode;

    /*

     * As above, initialize the first 256 entries in the table.

     */

    maxcode = MAXCODE(n_bits = INIT_BITS);

    for ( code = 255; code >= 0; code-- ) {

        tab_prefixof(code) = 0;

        tab_suffixof(code) = (char_type)code;

    }

    free_ent = ((block_compress) ? FIRST : 256 );

    finchar = oldcode = getcode();

    if(oldcode == -1)   /* EOF already? */

        return;                 /* Get out of here */

 /*   putchar( (char)finchar ); */      /* first code must be 8 bits = char */

   /* if(ferror(stdout))

        writeerr(); */

    stackp = de_stack;

    while ( (code = getcode()) > -1 ) {

        if ( (code == CLEAR) && block_compress ) {

            for ( code = 255; code >= 0; code-- )

                tab_prefixof(code) = 0;

            clear_flg = 1;

            free_ent = FIRST - 1;

            if ( (code = getcode ()) == -1 )    /* O, untimely death! */

                break;

        }

        incode = code;

        /*

         * Special case for KwKwK string.

         */

        if ( code >= free_ent ) {

            *stackp++ = finchar;

            code = oldcode;

        }

        /*

         * Generate output characters in reverse order

         */

#ifdef SIGNED_COMPARE_SLOW

        while ( ((unsigned long)code) >= ((unsigned long)256) ) {

#else

        while ( code >= 256 ) {

#endif

            *stackp++ = tab_suffixof(code);

            code = tab_prefixof(code);

        }

        *stackp++ = finchar = tab_suffixof(code);

        /*

         * And put them out in forward order

         */

        /* do

            putchar ( *--stackp );

        while ( stackp > de_stack );*/

        /*

         * Generate the new entry.

         */

        if ( (code=free_ent) < maxmaxcode ) {

            tab_prefixof(code) = (unsigned short)oldcode;

            tab_suffixof(code) = finchar;

            free_ent = code+1;

        }

        /*

         * Remember previous code.

         */

        oldcode = incode;

    }

  /*  fflush( stdout ); */

   /* if(ferror(stdout))

        writeerr(); */

}

/*****************************************************************

 * TAG( getcode )

 *

 * Read one code from the standard input.  If EOF, return -1.

 * Inputs:

 *      stdin

 * Outputs:

 *      code or -1 is returned.

 */

code_int

getcode() {

    /*

     * On the VAX, it is important to have the register declarations

     * in exactly the order given, or the asm will break.

     */

    register code_int code;

    static int offset = 0, size = 0;

    static char_type buf[BITS];

    register int r_off, bits;

    register char_type *bp = buf;

    if ( clear_flg > 0 || offset >= size || free_ent > maxcode ) {

        /*

         * If the next entry will be too big for the current code

         * size, then we must increase the size.  This implies reading

         * a new buffer full, too.

         */

        if ( free_ent > maxcode ) {

            n_bits++;

            if ( n_bits == maxbits )

                maxcode = maxmaxcode;   /* won't get any bigger now */

            else

                maxcode = MAXCODE(n_bits);

        }

        if ( clear_flg > 0) {

            maxcode = MAXCODE (n_bits = INIT_BITS);

            clear_flg = 0;

        }

        /* size = fread( buf, 1, n_bits, stdin ); */

        if ( size <= 0 )

            return -1;                  /* end of file */

        offset = 0;

        /* Round size down to integral number of codes */

        size = (size << 3) - (n_bits - 1);

    }

    r_off = offset;

    bits = n_bits;

#ifdef vax

    asm( "extzv   r10,r9,(r8),r11" );

#else /* not a vax */

        /*

         * Get to the first byte.

         */

        bp += (r_off >> 3);

        r_off &= 7;

        /* Get first part (low order bits) */

#ifdef NO_UCHAR

        code = ((*bp++ >> r_off) & rmask[8 - r_off]) & 0xff;

#else

        code = (*bp++ >> r_off);

#endif /* NO_UCHAR */

        bits -= (8 - r_off);

        r_off = 8 - r_off;              /* now, offset into code word */

        /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */

        if ( bits >= 8 ) {

#ifdef NO_UCHAR

            code |= (*bp++ & 0xff) << r_off;

#else

            code |= *bp++ << r_off;

#endif /* NO_UCHAR */

            r_off += 8;

            bits -= 8;

        }

        /* high order bits. */

        code |= (*bp & rmask[bits]) << r_off;

#endif /* vax */

    offset += n_bits;

    return code;

}

char *

rindex(s, c)            /* For those who don't have it in libc.a */

register char *s, c;

{

        char *p;

        for (p = NULL; *s; s++)

            if (*s == c)

                p = s;

        return(p);

}

/*

writeerr()

{

    perror ( ofname );

    unlink ( ofname );

    exit ( 1 );

}

*/

void cl_block ()                /* table clear for block compress */

{

    register long int rat;

    checkpoint = in_count + CHECK_GAP;

    if(in_count > 0x007fffff) { /* shift will overflow */

        rat = bytes_out >> 8;

        if(rat == 0) {           /* Don't divide by zero */

            rat = 0x7fffffff;

        } else {

            rat = in_count / rat;

        }

    } else {

        rat = (in_count << 8) / bytes_out;      /* 8 fractional bits */

    }

    if ( rat > ratio ) {

        ratio = rat;

    } else {

        ratio = 0;

        cl_hash ( (count_int) hsize );

        free_ent = FIRST;

        clear_flg = 1;

        output ( (code_int) CLEAR );

    }

}

void cl_hash(hsize)             /* reset code table */

        register count_int hsize;

{

#ifndef XENIX_16        /* Normal machine */

        register count_int *htab_p = htab+hsize;

#else

        register j;

        register long k = hsize;

        register count_int *htab_p;

#endif

        register long i;

        register long m1 = -1;

#ifdef XENIX_16

    for(j=0; j<=8 && k>=0; j++,k-=8192) {

        i = 8192;

        if(k < 8192) {

                i = k;

        }

        htab_p = &(htab[j][i]);

        i -= 16;

        if(i > 0) {

#else

        i = hsize - 16;

#endif

        do {                            /* might use Sys V memset(3) here */

                *(htab_p-16) = m1;

                *(htab_p-15) = m1;

                *(htab_p-14) = m1;