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tblcmp.c

/* tblcmp - table compression routines */
/* $Id: tblcmp.c,v 1.5 2000/06/01 17:06:09 waite Exp $ */

/*
 * Copyright (c) 1987, the University of California
 * 
 * The United States Government has rights in this work pursuant to
 * contract no. DE-AC03-76SF00098 between the United States Department of
 * Energy and the University of California.
 * 
 * This program may be redistributed.  Enhancements and derivative works
 * may be created provided the new works, if made available to the general
 * public, are made available for use by anyone.
 */

#include "flexdef.h"

/* bldtbl - build table entries for dfa state
 *
 * synopsis
 *   int state[numecs], statenum, totaltrans, comstate, comfreq;
 *   bldtbl( state, statenum, totaltrans, comstate, comfreq );
 *
 * State is the statenum'th dfa state.  It is indexed by equivalence class and
 * gives the number of the state to enter for a given equivalence class.
 * totaltrans is the total number of transitions out of the state.  Comstate
 * is that state which is the destination of the most transitions out of State.
 * Comfreq is how many transitions there are out of State to Comstate.
 *
 * A note on terminology:
 *    "protos" are transition tables which have a high probability of
 * either being redundant (a state processed later will have an identical
 * transition table) or nearly redundant (a state processed later will have
 * many of the same out-transitions).  A "most recently used" queue of
 * protos is kept around with the hope that most states will find a proto
 * which is similar enough to be usable, and therefore compacting the
 * output tables.
 *    "templates" are a special type of proto.  If a transition table is
 * homogeneous or nearly homogeneous (all transitions go to the same
 * destination) then the odds are good that future states will also go
 * to the same destination state on basically the same character set.
 * These homogeneous states are so common when dealing with large rule
 * sets that they merit special attention.  If the transition table were
 * simply made into a proto, then (typically) each subsequent, similar
 * state will differ from the proto for two out-transitions.  One of these
 * out-transitions will be that character on which the proto does not go
 * to the common destination, and one will be that character on which the
 * state does not go to the common destination.  Templates, on the other
 * hand, go to the common state on EVERY transition character, and therefore
 * cost only one difference.
 */

bldtbl( state, statenum, totaltrans, comstate, comfreq )
int state[], statenum, totaltrans, comstate, comfreq;

    {
    int extptr, extrct[2][CSIZE + 1];
    int mindiff, minprot, i, d;
    int checkcom;

    /* If extptr is 0 then the first array of extrct holds the result of the
     * "best difference" to date, which is those transitions which occur in
     * "state" but not in the proto which, to date, has the fewest differences
     * between itself and "state".  If extptr is 1 then the second array of
     * extrct hold the best difference.  The two arrays are toggled
     * between so that the best difference to date can be kept around and
     * also a difference just created by checking against a candidate "best"
     * proto.
     */

    extptr = 0;

    /* if the state has too few out-transitions, don't bother trying to
     * compact its tables
     */

    if ( (totaltrans * 100) < (numecs * PROTO_SIZE_PERCENTAGE) )
      mkentry( state, numecs, statenum, JAMSTATE, totaltrans );

    else
      {
      /* checkcom is true if we should only check "state" against
       * protos which have the same "comstate" value
       */

      checkcom = comfreq * 100 > totaltrans * CHECK_COM_PERCENTAGE;

      minprot = firstprot;
      mindiff = totaltrans;

      if ( checkcom )
          {
          /* find first proto which has the same "comstate" */
          for ( i = firstprot; i != NIL; i = protnext[i] )
            if ( protcomst[i] == comstate )
                {
                minprot = i;
                mindiff = tbldiff( state, minprot, extrct[extptr] );
                break;
                }
          }

      else
          {
          /* since we've decided that the most common destination out
           * of "state" does not occur with a high enough frequency,
           * we set the "comstate" to zero, assuring that if this state
           * is entered into the proto list, it will not be considered
           * a template.
           */
          comstate = 0;

          if ( firstprot != NIL )
            {
            minprot = firstprot;
            mindiff = tbldiff( state, minprot, extrct[extptr] );
            }
          }

      /* we now have the first interesting proto in "minprot".  If
       * it matches within the tolerances set for the first proto,
       * we don't want to bother scanning the rest of the proto list
       * to see if we have any other reasonable matches.
       */

      if ( mindiff * 100 > totaltrans * FIRST_MATCH_DIFF_PERCENTAGE )
          { /* not a good enough match.  Scan the rest of the protos */
          for ( i = minprot; i != NIL; i = protnext[i] )
            {
            d = tbldiff( state, i, extrct[1 - extptr] );
            if ( d < mindiff )
                {
                extptr = 1 - extptr;
                mindiff = d;
                minprot = i;
                }
            }
          }

      /* check if the proto we've decided on as our best bet is close
       * enough to the state we want to match to be usable
       */

      if ( mindiff * 100 > totaltrans * ACCEPTABLE_DIFF_PERCENTAGE )
          {
          /* no good.  If the state is homogeneous enough, we make a
           * template out of it.  Otherwise, we make a proto.
           */

          if ( comfreq * 100 >= totaltrans * TEMPLATE_SAME_PERCENTAGE )
            mktemplate( state, statenum, comstate );

          else
            {
            mkprot( state, statenum, comstate );
            mkentry( state, numecs, statenum, JAMSTATE, totaltrans );
            }
          }

      else
          { /* use the proto */
          mkentry( extrct[extptr], numecs, statenum,
                 prottbl[minprot], mindiff );

          /* if this state was sufficiently different from the proto
           * we built it from, make it, too, a proto
           */

          if ( mindiff * 100 >= totaltrans * NEW_PROTO_DIFF_PERCENTAGE )
            mkprot( state, statenum, comstate );

          /* since mkprot added a new proto to the proto queue, it's possible
           * that "minprot" is no longer on the proto queue (if it happened
           * to have been the last entry, it would have been bumped off).
           * If it's not there, then the new proto took its physical place
           * (though logically the new proto is at the beginning of the
           * queue), so in that case the following call will do nothing.
           */

          mv2front( minprot );
          }
      }
    }


/* cmptmps - compress template table entries
 *
 * synopsis
 *    cmptmps();
 *
 *  template tables are compressed by using the 'template equivalence
 *  classes', which are collections of transition character equivalence
 *  classes which always appear together in templates - really meta-equivalence
 *  classes.  until this point, the tables for templates have been stored
 *  up at the top end of the nxt array; they will now be compressed and have
 *  table entries made for them.
 */

cmptmps()

    {
    int tmpstorage[CSIZE + 1];
    register int *tmp = tmpstorage, i, j;
    int totaltrans, trans;

    peakpairs = numtemps * numecs + tblend;

    if ( usemecs )
      {
      /* create equivalence classes base on data gathered on template
       * transitions
       */

      nummecs = cre8ecs( tecfwd, tecbck, numecs );
      }
    
    else
      nummecs = numecs;

    if ( lastdfa + numtemps + 1 >= current_max_dfas )
      increase_max_dfas();

    /* loop through each template */

    for ( i = 1; i <= numtemps; ++i )
      {
      totaltrans = 0;   /* number of non-jam transitions out of this template */

      for ( j = 1; j <= numecs; ++j )
          {
          trans = tnxt[numecs * i + j];

          if ( usemecs )
            {
            /* the absolute value of tecbck is the meta-equivalence class
             * of a given equivalence class, as set up by cre8ecs
             */
            if ( tecbck[j] > 0 )
                {
                tmp[tecbck[j]] = trans;

                if ( trans > 0 )
                  ++totaltrans;
                }
            }

          else
            {
            tmp[j] = trans;

            if ( trans > 0 )
                ++totaltrans;
            }
          }

      /* it is assumed (in a rather subtle way) in the skeleton that
       * if we're using meta-equivalence classes, the def[] entry for
       * all templates is the jam template, i.e., templates never default
       * to other non-jam table entries (e.g., another template)
       */

      /* leave room for the jam-state after the last real state */
      mkentry( tmp, nummecs, lastdfa + i + 1, JAMSTATE, totaltrans );
      }
    }



/* expand_nxt_chk - expand the next check arrays */

expand_nxt_chk()

    {
    register int old_max = current_max_xpairs;

    current_max_xpairs += MAX_XPAIRS_INCREMENT;

    ++num_reallocs;

    nxt = reallocate_integer_array( nxt, current_max_xpairs );
    chk = reallocate_integer_array( chk, current_max_xpairs );

    bzero( (char *) (chk + old_max),
         MAX_XPAIRS_INCREMENT * sizeof( int ) / sizeof( char ) );
    }


/* find_table_space - finds a space in the table for a state to be placed
 *
 * synopsis
 *     int *state, numtrans, block_start;
 *     int find_table_space();
 *
 *     block_start = find_table_space( state, numtrans );
 *
 * State is the state to be added to the full speed transition table.
 * Numtrans is the number of out-transitions for the state.
 *
 * find_table_space() returns the position of the start of the first block (in
 * chk) able to accommodate the state
 *
 * In determining if a state will or will not fit, find_table_space() must take
 * into account the fact that an end-of-buffer state will be added at [0],
 * and an action number will be added in [-1].
 */

int find_table_space( state, numtrans )
int *state, numtrans;
    
    {
    /* firstfree is the position of the first possible occurrence of two
     * consecutive unused records in the chk and nxt arrays
     */
    register int i;
    register int *state_ptr, *chk_ptr;
    register int *ptr_to_last_entry_in_state;

    /* if there are too many out-transitions, put the state at the end of
     * nxt and chk
     */
    if ( numtrans > MAX_XTIONS_FOR_FULL_INTERIOR_FIT )
      {
      /* if table is empty, return the first available spot in chk/nxt,
       * which should be 1
       */
      if ( tblend < 2 )
          return ( 1 );

      i = tblend - numecs;    /* start searching for table space near the
                         * end of chk/nxt arrays
                         */
      }

    else
      i = firstfree;          /* start searching for table space from the
                         * beginning (skipping only the elements
                         * which will definitely not hold the new
                         * state)
                         */

    while ( 1 )         /* loops until a space is found */
      {
      if ( i + numecs > current_max_xpairs )
          expand_nxt_chk();

      /* loops until space for end-of-buffer and action number are found */
      while ( 1 )
          {
          if ( chk[i - 1] == 0 )    /* check for action number space */
            {
            if ( chk[i] == 0 )      /* check for end-of-buffer space */
                break;

            else
                i += 2; /* since i != 0, there is no use checking to
                         * see if (++i) - 1 == 0, because that's the
                         * same as i == 0, so we skip a space
                         */
            }

          else
            ++i;

          if ( i + numecs > current_max_xpairs )
            expand_nxt_chk();
          }

      /* if we started search from the beginning, store the new firstfree for
       * the next call of find_table_space()
       */
      if ( numtrans <= MAX_XTIONS_FOR_FULL_INTERIOR_FIT )
          firstfree = i + 1;

      /* check to see if all elements in chk (and therefore nxt) that are
       * needed for the new state have not yet been taken
       */

      state_ptr = &state[1];
      ptr_to_last_entry_in_state = &chk[i + numecs + 1];

      for ( chk_ptr = &chk[i + 1]; chk_ptr != ptr_to_last_entry_in_state;
            ++chk_ptr )
          if ( *(state_ptr++) != 0 && *chk_ptr != 0 )
            break;

      if ( chk_ptr == ptr_to_last_entry_in_state )
          return ( i );

      else
          ++i;
      }
    }


/* genctbl - generates full speed compressed transition table
 *
 * synopsis
 *     genctbl();
 */

genctbl()

    {
    register int i;

    /* table of verify for transition and offset to next state */
    printf( "static struct yy_trans_info yy_transition[%d] =\n",
          tblend + numecs + 1 );
    printf( "    {\n" );
    
    /* We want the transition to be represented as the offset to the
     * next state, not the actual state number, which is what it currently is.
     * The offset is base[nxt[i]] - base[chk[i]].  That's just the
     * difference between the starting points of the two involved states
     * (to - from).
     *
     * first, though, we need to find some way to put in our end-of-buffer
     * flags and states.  We do this by making a state with absolutely no
     * transitions.  We put it at the end of the table.
     */
    /* at this point, we're guaranteed that there's enough room in nxt[]
     * and chk[] to hold tblend + numecs entries.  We need just two slots.
     * One for the action and one for the end-of-buffer transition.  We
     * now *assume* that we're guaranteed the only character we'll try to
     * index this nxt/chk pair with is EOB, i.e., 0, so we don't have to
     * make sure there's room for jam entries for other characters.
     */

    base[lastdfa + 1] = tblend + 2;
    nxt[tblend + 1] = END_OF_BUFFER_ACTION;
    chk[tblend + 1] = numecs + 1;
    chk[tblend + 2] = 1; /* anything but EOB */
    nxt[tblend + 2] = 0; /* so that "make test" won't show arb. differences */

    /* make sure every state has a end-of-buffer transition and an action # */
    for ( i = 0; i <= lastdfa; ++i )
      {
      chk[base[i]] = EOB_POSITION;
      chk[base[i] - 1] = ACTION_POSITION;
      nxt[base[i] - 1] = dfaacc[i].dfaacc_state;      /* action number */
      }

    for ( i = 0; i <= lastsc * 2; ++i )
      nxt[base[i] - 1] = DEFAULT_ACTION;

    dataline = 0;
    datapos = 0;

    for ( i = 0; i <= tblend; ++i )
      {
      if ( chk[i] == EOB_POSITION )
          transition_struct_out( 0, base[lastdfa + 1] - i );

      else if ( chk[i] == ACTION_POSITION )
          transition_struct_out( 0, nxt[i] );

      else if ( chk[i] > numecs || chk[i] == 0 )
          transition_struct_out( 0, 0 );        /* unused slot */

      else  /* verify, transition */
          transition_struct_out( chk[i], base[nxt[i]] - (i - chk[i]) );
      }


    /* here's the final, end-of-buffer state */
    transition_struct_out( chk[tblend + 1], nxt[tblend + 1] );
    transition_struct_out( chk[tblend + 2], nxt[tblend + 2] );

    printf( "    };\n" );
    printf( "\n" );

    /* table of pointers to start states */
    printf( "static struct yy_trans_info *yy_state_ptr[%d] =\n",
      lastsc * 2 + 1 );
    printf( "    {\n" );

    for ( i = 0; i <= lastsc * 2; ++i )
      printf( "    &yy_transition[%d],\n", base[i] );

    printf( "    };\n" );

    if ( useecs )
      genecs();
    }


/* gentabs - generate data statements for the transition tables
 *
 * synopsis
 *    gentabs();
 */

gentabs()

    {
    int i, j, k, *accset, nacc, *acc_array;

    /* *everything* is done in terms of arrays starting at 1, so provide
     * a null entry for the zero element of all FTL arrays
     */
    static char ftl_long_decl[] = "static long int %c[%d] =\n    {   0,\n";
    static char ftl_short_decl[] = "static short int %c[%d] =\n    {   0,\n";
    static char ftl_char_decl[] = "static char %c[%d] =\n    {   0,\n";

    acc_array = allocate_integer_array( current_max_dfas );
    nummt = 0;

    if ( fulltbl )
      jambase = lastdfa + 1;  /* home of "jam" pseudo-state */

    printf( "#define YY_JAM %d\n", jamstate );
    printf( "#define YY_JAM_BASE %d\n", jambase );

    if ( usemecs )
      printf( "#define YY_TEMPLATE %d\n", lastdfa + 2 );

    if ( reject )
      {
      /* write out accepting list and pointer list
       * first we generate the ACCEPT array.  In the process, we compute
       * the indices that will go into the ALIST array, and save the
       * indices in the dfaacc array
       */

      printf( accnum > 127 ? ftl_short_decl : ftl_char_decl,
            ACCEPT, max( numas, 1 ) + 1 );

      j = 1;      /* index into ACCEPT array */

      for ( i = 1; i <= lastdfa; ++i )
          {
          acc_array[i] = j;

          if ( accsiz[i] != 0 )
            {
            accset = dfaacc[i].dfaacc_set;
            nacc = accsiz[i];

            if ( trace )
                fprintf( stderr, "state # %d accepts: ", i );

            for ( k = 1; k <= nacc; ++k )
                {
                ++j;
                mkdata( accset[k] );

                if ( trace )
                  {
                  fprintf( stderr, "[%d]", accset[k] );

                  if ( k < nacc )
                      fputs( ", ", stderr );
                  else
                      putc( '\n', stderr );
                  }
                }
            }
          }

      /* add accepting number for the "jam" state */
      acc_array[i] = j;

      dataend();
      }
    
    else
      {
      for ( i = 1; i <= lastdfa; ++i )
          acc_array[i] = dfaacc[i].dfaacc_state;
      
      acc_array[i] = 0; /* add (null) accepting number for jam state */
      acc_array[0] = 0;                               /* GLA */
      {
      FILE *fd = fopen("accept.binary", "wb");                    /* GLA */
      if(!fd) { perror("accept.binary"); exit(1); }               /* GLA */
      fwrite((void *)acc_array, sizeof(acc_array[0]), (size_t)(lastdfa+1), fd);           /* GLA */
      }                                               /* GLA */
      }

    /* spit out ALIST array.  If we're doing "reject", it'll be pointers
     * into the ACCEPT array.  Otherwise it's actual accepting numbers.
     * In either case, we just dump the numbers.
     */

    /* "lastdfa + 2" is the size of ALIST; includes room for FTL arrays
     * beginning at 0 and for "jam" state
     */
    k = lastdfa + 2;

    if ( reject )
      /* we put a "cap" on the table associating lists of accepting
       * numbers with state numbers.  This is needed because we tell
       * where the end of an accepting list is by looking at where
       * the list for the next state starts.
       */
      ++k;

#ifdef UNSIGNED_CHAR
    printf( ftl_short_decl, ALIST, k );
#else
    printf( ((reject && numas > 126) || accnum > 127) ?
            ftl_short_decl : ftl_char_decl, ALIST, k );
#endif

    /* set up default actions */
    for ( i = 1; i <= lastsc * 2; ++i )
      acc_array[i] = DEFAULT_ACTION;

    acc_array[end_of_buffer_state] = END_OF_BUFFER_ACTION;

    for ( i = 1; i <= lastdfa; ++i )
      {
      mkdata( acc_array[i] );

      if ( ! reject && trace && acc_array[i] )
          fprintf( stderr, "state # %d accepts: [%d]\n", i, acc_array[i] );
      }

    /* add entry for "jam" state */
    mkdata( acc_array[i] );

    if ( reject )
      /* add "cap" for the list */
      mkdata( acc_array[i] );

    dataend();

    if ( useecs )
      genecs();

    if ( usemecs )
      {
      /* write out meta-equivalence classes (used to index templates with) */

      if ( trace )
          fputs( "\n\nMeta-Equivalence Classes:\n", stderr );

      printf( ftl_char_decl, MATCHARRAY, numecs + 1 );

      for ( i = 1; i <= numecs; ++i )
          {
          if ( trace )
            fprintf( stderr, "%d = %d\n", i, abs( tecbck[i] ) );

          mkdata( abs( tecbck[i] ) );
          }

      dataend();
      }

    if ( ! fulltbl )
      {
      int total_states = lastdfa + numtemps;

      printf( tblend > MAX_SHORT ? ftl_long_decl : ftl_short_decl,
            BASEARRAY, total_states + 1 );

      for ( i = 1; i <= lastdfa; ++i )
          {
          register int d = def[i];

          if ( base[i] == JAMSTATE )
            base[i] = jambase;

          if ( d == JAMSTATE )
            def[i] = jamstate;

          else if ( d < 0 )
            {
            /* template reference */
            ++tmpuses;
            def[i] = lastdfa - d + 1;
            }

          mkdata( base[i] );
          }

      /* generate jam state's base index */
      mkdata( base[i] );

      for ( ++i /* skip jam state */; i <= total_states; ++i )
          {
          mkdata( base[i] );
          def[i] = jamstate;
          }

      dataend();

      printf( tblend > MAX_SHORT ? ftl_long_decl : ftl_short_decl,
            DEFARRAY, total_states + 1 );

      for ( i = 1; i <= total_states; ++i )
          mkdata( def[i] );

      dataend();

      printf( lastdfa > MAX_SHORT ? ftl_long_decl : ftl_short_decl,
            NEXTARRAY, tblend + 1 );

      for ( i = 1; i <= tblend; ++i )
          {
            if ( nxt[i] == 0 || chk[i] == 0 )
            nxt[i] = jamstate;      /* new state is the JAM state */

          mkdata( nxt[i] );
          }

      dataend();

      printf( lastdfa > MAX_SHORT ? ftl_long_decl : ftl_short_decl,
            CHECKARRAY, tblend + 1 );

      for ( i = 1; i <= tblend; ++i )
          {
          if ( chk[i] == 0 )
            ++nummt;

          mkdata( chk[i] );
          }

      dataend();
      }
    }


/* generate equivalence-class tables */

genecs()

    {
    register int i, j;
    static char ftl_char_decl[] = "static char %c[%d] =\n    {   0,\n";
    int numrows;
    char clower();

    printf( ftl_char_decl, ECARRAY, CSIZE + 1 );

    for ( i = 1; i <= CSIZE; ++i )
      {
      if ( caseins && (i >= 'A') && (i <= 'Z') )
          ecgroup[i] = ecgroup[clower( i )];

      ecgroup[i] = abs( ecgroup[i] );
      mkdata( ecgroup[i] );
      }

    dataend();

    if ( trace )
      {
      fputs( "\n\nEquivalence Classes:\n\n", stderr );

      numrows = (CSIZE + 1) / 8;

      for ( j = 1; j <= numrows; ++j )
          {
          for ( i = j; i <= CSIZE; i = i + numrows )
            {
            if ( i >= 1 && i <= 31 )
                fprintf( stderr, "^%c = %-2d",
                       'A' + i - 1, ecgroup[i] );

            else if ( i >= 32 && i <= 126 )
                fprintf( stderr, " %c = %-2d", i, ecgroup[i] );

            else if ( i == 127 )
                fprintf( stderr, "^@ = %-2d", ecgroup[i] );

            else
                fprintf( stderr, "\nSomething Weird: %d = %d\n", i,
                       ecgroup[i] );

            putc( '\t', stderr );
            }

          putc( '\n', stderr );
          }
      }
    }


/* inittbl - initialize transition tables
 *
 * synopsis
 *   inittbl();
 *
 * Initializes "firstfree" to be one beyond the end of the table.  Initializes
 * all "chk" entries to be zero.  Note that templates are built in their
 * own tbase/tdef tables.  They are shifted down to be contiguous
 * with the non-template entries during table generation.
 */
inittbl()

    {
    register int i;

    bzero( (char *) chk, current_max_xpairs * sizeof( int ) / sizeof( char ) );

    tblend = 0;
    firstfree = tblend + 1;
    numtemps = 0;

    if ( usemecs )
      {
      /* set up doubly-linked meta-equivalence classes
       * these are sets of equivalence classes which all have identical
       * transitions out of TEMPLATES
       */

      tecbck[1] = NIL;

      for ( i = 2; i <= numecs; ++i )
          {
          tecbck[i] = i - 1;
          tecfwd[i - 1] = i;
          }

      tecfwd[numecs] = NIL;
      }
    }


/* make_tables - generate transition tables
 *
 * synopsis
 *     make_tables();
 *
 * Generates transition tables and finishes generating output file
 */

make_tables()

    {
    if ( fullspd )
      { /* need to define YY_TRANS_OFFSET_TYPE as a size large
         * enough to hold the biggest offset
         */
      int total_table_size = tblend + numecs + 1;

      printf( "#define YY_TRANS_OFFSET_TYPE %s\n",
            total_table_size > MAX_SHORT ? "long" : "short" );
      }
    
    if ( fullspd || fulltbl )
      skelout();

    /* compute the tables and copy them to output file */
    if ( fullspd )
      genctbl();

    else
      gentabs();

    skelout();

    (void) fclose( temp_action_file );
    temp_action_file = fopen( action_file_name, "r" );

    /* copy prolog from action_file to output file */
    action_out();

    skelout();

    /* copy actions from action_file to output file */
    action_out();

    skelout();

    /* copy remainder of input to output */

    line_directive_out( stdout );
    (void) flexscan(); /* copy remainder of input to output */
    }


/* mkdeftbl - make the default, "jam" table entries
 *
 * synopsis
 *   mkdeftbl();
 */

mkdeftbl()

    {
    int i;

    jamstate = lastdfa + 1;

    if ( tblend + numecs > current_max_xpairs )
      expand_nxt_chk();

    for ( i = 1; i <= numecs; ++i )
      {
      nxt[tblend + i] = 0;
      chk[tblend + i] = jamstate;
      }

    jambase = tblend;

    base[jamstate] = jambase;

    /* should generate a run-time array bounds check if
     * ever used as a default
     */
    def[jamstate] = BAD_SUBSCRIPT;

    tblend += numecs;
    ++numtemps;
    }


/* mkentry - create base/def and nxt/chk entries for transition array
 *
 * synopsis
 *   int state[numchars + 1], numchars, statenum, deflink, totaltrans;
 *   mkentry( state, numchars, statenum, deflink, totaltrans );
 *
 * "state" is a transition array "numchars" characters in size, "statenum"
 * is the offset to be used into the base/def tables, and "deflink" is the
 * entry to put in the "def" table entry.  If "deflink" is equal to
 * "JAMSTATE", then no attempt will be made to fit zero entries of "state"
 * (i.e., jam entries) into the table.  It is assumed that by linking to
 * "JAMSTATE" they will be taken care of.  In any case, entries in "state"
 * marking transitions to "SAME_TRANS" are treated as though they will be
 * taken care of by whereever "deflink" points.  "totaltrans" is the total
 * number of transitions out of the state.  If it is below a certain threshold,
 * the tables are searched for an interior spot that will accommodate the
 * state array.
 */

mkentry( state, numchars, statenum, deflink, totaltrans )
register int *state;
int numchars, statenum, deflink, totaltrans;

    {
    register int minec, maxec, i, baseaddr;
    int tblbase, tbllast;

    if ( totaltrans == 0 )
      { /* there are no out-transitions */
      if ( deflink == JAMSTATE )
          base[statenum] = JAMSTATE;
      else
          base[statenum] = 0;

      def[statenum] = deflink;
      return;
      }

    for ( minec = 1; minec <= numchars; ++minec )
      {
      if ( state[minec] != SAME_TRANS )
          if ( state[minec] != 0 || deflink != JAMSTATE )
            break;
      }

    if ( totaltrans == 1 )
      {
      /* there's only one out-transition.  Save it for later to fill
       * in holes in the tables.
       */
      stack1( statenum, minec, state[minec], deflink );
      return;
      }

    for ( maxec = numchars; maxec > 0; --maxec )
      {
      if ( state[maxec] != SAME_TRANS )
          if ( state[maxec] != 0 || deflink != JAMSTATE )
            break;
      }

    /* Whether we try to fit the state table in the middle of the table
     * entries we have already generated, or if we just take the state
     * table at the end of the nxt/chk tables, we must make sure that we
     * have a valid base address (i.e., non-negative).  Note that not only are
     * negative base addresses dangerous at run-time (because indexing the
     * next array with one and a low-valued character might generate an
     * array-out-of-bounds error message), but at compile-time negative
     * base addresses denote TEMPLATES.
     */

    /* find the first transition of state that we need to worry about. */
    if ( totaltrans * 100 <= numchars * INTERIOR_FIT_PERCENTAGE )
      { /* attempt to squeeze it into the middle of the tabls */
      baseaddr = firstfree;

      while ( baseaddr < minec )
          {
          /* using baseaddr would result in a negative base address below
           * find the next free slot
           */
          for ( ++baseaddr; chk[baseaddr] != 0; ++baseaddr )
            ;
          }

      if ( baseaddr + maxec - minec >= current_max_xpairs )
          expand_nxt_chk();

      for ( i = minec; i <= maxec; ++i )
          if ( state[i] != SAME_TRANS )
            if ( state[i] != 0 || deflink != JAMSTATE )
                if ( chk[baseaddr + i - minec] != 0 )
                  { /* baseaddr unsuitable - find another */
                  for ( ++baseaddr;
                        baseaddr < current_max_xpairs &&
                        chk[baseaddr] != 0;
                        ++baseaddr )
                      ;

                  if ( baseaddr + maxec - minec >= current_max_xpairs )
                      expand_nxt_chk();

                  /* reset the loop counter so we'll start all
                   * over again next time it's incremented
                   */

                  i = minec - 1;
                  }
      }

    else
      {
      /* ensure that the base address we eventually generate is
       * non-negative
       */
      baseaddr = max( tblend + 1, minec );
      }

    tblbase = baseaddr - minec;
    tbllast = tblbase + maxec;

    if ( tbllast >= current_max_xpairs )
      expand_nxt_chk();

    base[statenum] = tblbase;
    def[statenum] = deflink;

    for ( i = minec; i <= maxec; ++i )
      if ( state[i] != SAME_TRANS )
          if ( state[i] != 0 || deflink != JAMSTATE )
            {
            nxt[tblbase + i] = state[i];
            chk[tblbase + i] = statenum;
            }

    if ( baseaddr == firstfree )
      /* find next free slot in tables */
      for ( ++firstfree; chk[firstfree] != 0; ++firstfree )
          ;

    tblend = max( tblend, tbllast );
    }


/* mk1tbl - create table entries for a state (or state fragment) which
 *            has only one out-transition
 *
 * synopsis
 *   int state, sym, onenxt, onedef;
 *   mk1tbl( state, sym, onenxt, onedef );
 */

mk1tbl( state, sym, onenxt, onedef )
int state, sym, onenxt, onedef;

    {
    if ( firstfree < sym )
      firstfree = sym;

    while ( chk[firstfree] != 0 )
      if ( ++firstfree >= current_max_xpairs )
          expand_nxt_chk();

    base[state] = firstfree - sym;
    def[state] = onedef;
    chk[firstfree] = state;
    nxt[firstfree] = onenxt;

    if ( firstfree > tblend )
      {
      tblend = firstfree++;

      if ( firstfree >= current_max_xpairs )
          expand_nxt_chk();
      }
    }


/* mkprot - create new proto entry
 *
 * synopsis
 *   int state[], statenum, comstate;
 *   mkprot( state, statenum, comstate );
 */

mkprot( state, statenum, comstate )
int state[], statenum, comstate;

    {
    int i, slot, tblbase;

    if ( ++numprots >= MSP || numecs * numprots >= PROT_SAVE_SIZE )
      {
      /* gotta make room for the new proto by dropping last entry in
       * the queue
       */
      slot = lastprot;
      lastprot = protprev[lastprot];
      protnext[lastprot] = NIL;
      }

    else
      slot = numprots;

    protnext[slot] = firstprot;

    if ( firstprot != NIL )
      protprev[firstprot] = slot;

    firstprot = slot;
    prottbl[slot] = statenum;
    protcomst[slot] = comstate;

    /* copy state into save area so it can be compared with rapidly */
    tblbase = numecs * (slot - 1);

    for ( i = 1; i <= numecs; ++i )
      protsave[tblbase + i] = state[i];
    }


/* mktemplate - create a template entry based on a state, and connect the state
 *              to it
 *
 * synopsis
 *   int state[], statenum, comstate, totaltrans;
 *   mktemplate( state, statenum, comstate, totaltrans );
 */

mktemplate( state, statenum, comstate )
int state[], statenum, comstate;

    {
    int i, numdiff, tmpbase, tmp[CSIZE + 1];
    char transset[CSIZE + 1];
    int tsptr;

    ++numtemps;

    tsptr = 0;

    /* calculate where we will temporarily store the transition table
     * of the template in the tnxt[] array.  The final transition table
     * gets created by cmptmps()
     */

    tmpbase = numtemps * numecs;

    if ( tmpbase + numecs >= current_max_template_xpairs )
      {
      current_max_template_xpairs += MAX_TEMPLATE_XPAIRS_INCREMENT;

      ++num_reallocs;

      tnxt = reallocate_integer_array( tnxt, current_max_template_xpairs );
      }

    for ( i = 1; i <= numecs; ++i )
      if ( state[i] == 0 )
          tnxt[tmpbase + i] = 0;
      else
          {
          transset[tsptr++] = i;
          tnxt[tmpbase + i] = comstate;
          }

    if ( usemecs )
      mkeccl( transset, tsptr, tecfwd, tecbck, numecs );

    mkprot( tnxt + tmpbase, -numtemps, comstate );

    /* we rely on the fact that mkprot adds things to the beginning
     * of the proto queue
     */

    numdiff = tbldiff( state, firstprot, tmp );
    mkentry( tmp, numecs, statenum, -numtemps, numdiff );
    }


/* mv2front - move proto queue element to front of queue
 *
 * synopsis
 *   int qelm;
 *   mv2front( qelm );
 */

mv2front( qelm )
int qelm;

    {
    if ( firstprot != qelm )
      {
      if ( qelm == lastprot )
          lastprot = protprev[lastprot];

      protnext[protprev[qelm]] = protnext[qelm];

      if ( protnext[qelm] != NIL )
          protprev[protnext[qelm]] = protprev[qelm];

      protprev[qelm] = NIL;
      protnext[qelm] = firstprot;
      protprev[firstprot] = qelm;
      firstprot = qelm;
      }
    }


/* ntod - convert an ndfa to a dfa
 *
 * synopsis
 *    ntod();
 *
 *  creates the dfa corresponding to the ndfa we've constructed.  the
 *  dfa starts out in state #1.
 */
ntod()

    {
    int *accset, ds, nacc, newds;
    int duplist[CSIZE + 1], sym, hashval, numstates, dsize;
    int targfreq[CSIZE + 1], targstate[CSIZE + 1], state[CSIZE + 1];
    int *nset, *dset;
    int targptr, totaltrans, i, comstate, comfreq, targ;
    int *epsclosure(), snstods(), symlist[CSIZE + 1];

    FILE *glafd;                                /* GLA */
    int firstWrite = 0;                               /* GLA */

    /* this is so find_table_space(...) will know where to start looking in
     * chk/nxt for unused records for space to put in the state
     */
    if ( fullspd )
      firstfree = 0;

    accset = allocate_integer_array( accnum + 1 );
    nset = allocate_integer_array( current_max_dfa_size );

    todo_head = todo_next = 0;

#define ADD_QUEUE_ELEMENT(element) \
      if ( ++element >= current_max_dfas ) \
          { /* check for queue overflowing */ \
          if ( todo_head == 0 ) \
            increase_max_dfas(); \
          else \
            element = 0; \
          }

#define NEXT_QUEUE_ELEMENT(element) ((element + 1) % (current_max_dfas + 1))

    for ( i = 0; i <= CSIZE; ++i )
      {
      duplist[i] = NIL;
      symlist[i] = false;
      }

    for ( i = 0; i <= accnum; ++i )
      accset[i] = NIL;

    if ( trace )
      {
      dumpnfa( scset[1] );
      fputs( "\n\nDFA Dump:\n\n", stderr );
      }

    inittbl();

    if ( fullspd )
      {
      for ( i = 0; i <= numecs; ++i )
          state[i] = 0;
      place_state( state, 0, 0 );
      }

    if ( fulltbl )
      {
      /* declare it "short" because it's a real long-shot that that
       * won't be large enough
       */
      printf( "static short int %c[][%d] =\n    {\n", NEXTARRAY,
            numecs + 1 ); /* '}' so vi doesn't get too confused */

      /* generate 0 entries for state #0 */
      for ( i = 0; i <= numecs; ++i )
          mk2data( 0 );

      /* force ',' and dataflush() next call to mk2data */
      datapos = NUMDATAITEMS;

      /* force extra blank line next dataflush() */
      dataline = NUMDATALINES;
      }

    /* create the first states */

    for ( i = 1; i <= lastsc * 2; ++i )
      {
      numstates = 1;

      /* for each start condition, make one state for the case when
       * we're at the beginning of the line (the '%' operator) and
       * one for the case when we're not
       */
      if ( i % 2 == 1 )
          nset[numstates] = scset[(i / 2) + 1];
      else
          nset[numstates] = mkbranch( scbol[i / 2], scset[i / 2] );

      nset = epsclosure( nset, &numstates, accset, &nacc, &hashval );

      if ( snstods( nset, numstates, accset, nacc, hashval, &ds ) )
          {
          numas = numas + nacc;
          totnst = totnst + numstates;

          todo[todo_next] = ds;
          ADD_QUEUE_ELEMENT(todo_next);
          }
      }

    if ( fulltbl )
      {
      if(GLAflg) {                              /* GLA */
            glafd = fopen("flex.binary", "wb"); /* GLA */
            if(!glafd) { perror("flex.binary"); exit(1); }  /* GLA */
            }                             /* GLA */

      if ( ! snstods( nset, 0, accset, 0, 0, &end_of_buffer_state ) )
          flexfatal( "could not create unique end-of-buffer state" );

      numas += 1;

      todo[todo_next] = end_of_buffer_state;
      ADD_QUEUE_ELEMENT(todo_next);
      }

    while ( todo_head != todo_next )
      {
      targptr = 0;
      totaltrans = 0;

      for ( i = 1; i <= numecs; ++i )
          state[i] = 0;

      ds = todo[todo_head];
      todo_head = NEXT_QUEUE_ELEMENT(todo_head);

      dset = dss[ds];
      dsize = dfasiz[ds];

      if ( trace )
          fprintf( stderr, "state # %d:\n", ds );

      sympartition( dset, dsize, symlist, duplist );

      for ( sym = 1; sym <= numecs; ++sym )
          {
          if ( symlist[sym] )
            {
            symlist[sym] = 0;

            if ( duplist[sym] == NIL )
                { /* symbol has unique out-transitions */
                numstates = symfollowset( dset, dsize, sym, nset );
                nset = epsclosure( nset, &numstates, accset,
                               &nacc, &hashval );

                if ( snstods( nset, numstates, accset,
                          nacc, hashval, &newds ) )
                  {
                  totnst = totnst + numstates;
                  todo[todo_next] = newds;
                  ADD_QUEUE_ELEMENT(todo_next);
                  numas = numas + nacc;
                  }

                state[sym] = newds;

                if ( trace )
                  fprintf( stderr, "\t%d\t%d\n", sym, newds );

                targfreq[++targptr] = 1;
                targstate[targptr] = newds;
                ++numuniq;
                }

            else
                {
                /* sym's equivalence class has the same transitions
                 * as duplist(sym)'s equivalence class
                 */
                targ = state[duplist[sym]];
                state[sym] = targ;

                if ( trace )
                  fprintf( stderr, "\t%d\t%d\n", sym, targ );

                /* update frequency count for destination state */

                i = 0;
                while ( targstate[++i] != targ )
                  ;

                ++targfreq[i];
                ++numdup;
                }

            ++totaltrans;
            duplist[sym] = NIL;
            }
          } /* endfor */

      numsnpairs = numsnpairs + totaltrans;

      if ( caseins && ! useecs )
          {
          register int j;

          for ( i = 'A', j = 'a'; i <= 'Z'; ++i, ++j )
            state[i] = state[j];
          }

      if ( fulltbl )
          {
          /* supply array's 0-element */
          if ( ds == end_of_buffer_state )
            mk2data( 0 );
          else
            mk2data( end_of_buffer_state );

          for ( i = 1; i <= numecs; ++i )
            mk2data( state[i] );

          if(GLAflg) {                          /* GLA */
                state[0] = 0;                   /* GLA */
                fwrite((void *)state, sizeof(int), (size_t)128, glafd); /* GLA */
                /* - get table offsets to match GLAs */     /* GLA */
                if(firstWrite==0) {                   /* GLA */
                  firstWrite = 1;                     /* GLA */
                  fwrite((void *)state, sizeof(int), (size_t)128, glafd);     /* GLA */
                  }                             /* GLA */
                }                               /* GLA */

          /* force ',' and dataflush() next call to mk2data */
          datapos = NUMDATAITEMS;

          /* force extra blank line next dataflush() */
          dataline = NUMDATALINES;
          }

        else if ( fullspd )
          place_state( state, ds, totaltrans );

      else
          {
          /* determine which destination state is the most common, and
           * how many transitions to it there are
           */

          comfreq = 0;
          comstate = 0;

          for ( i = 1; i <= targptr; ++i )
            if ( targfreq[i] > comfreq )
                {
                comfreq = targfreq[i];
                comstate = targstate[i];
                }

          bldtbl( state, ds, totaltrans, comstate, comfreq );
          }
      } /* endwhile */

    if ( fulltbl ){
      if(GLAflg) {                                    /* GLA */
            int nstates = lastdfa+1;                  /* GLA */
            FILE *fd = fopen("lastdfa.binary", "wb");       /* GLA */
            if(!fd) { perror("lastdfa.binary"); exit(1); }  /* GLA */
            fwrite((void *)&nstates, sizeof(nstates), (size_t)1, fd);   /* GLA */
            }                                   /* GLA */
      dataend();
      }

    else
      {
      cmptmps();  /* create compressed template entries */

      /* create tables for all the states with only one out-transition */
      while ( onesp > 0 )
          {
          mk1tbl( onestate[onesp], onesym[onesp], onenext[onesp],
                onedef[onesp] );
          --onesp;
          }

      mkdeftbl();
      }
    
    }


/* place_state - place a state into full speed transition table
 *
 * synopsis
 *     int *state, statenum, transnum;
 *     place_state( state, statenum, transnum );
 *
 * State is the statenum'th state.  It is indexed by equivalence class and
 * gives the number of the state to enter for a given equivalence class.
 * Transnum is the number of out-transitions for the state.
 */

place_state( state, statenum, transnum )
int *state, statenum, transnum;

    {
    register int i;
    register int *state_ptr;
    int position = find_table_space( state, transnum );

    /* base is the table of start positions */
    base[statenum] = position;

    /* put in action number marker; this non-zero number makes sure that
     * find_table_space() knows that this position in chk/nxt is taken
     * and should not be used for another accepting number in another state
     */
    chk[position - 1] = 1;

    /* put in end-of-buffer marker; this is for the same purposes as above */
    chk[position] = 1;

    /* place the state into chk and nxt */
    state_ptr = &state[1];

    for ( i = 1; i <= numecs; ++i, ++state_ptr )
      if ( *state_ptr != 0 )
          {
          chk[position + i] = i;
          nxt[position + i] = *state_ptr;
          }

    if ( position + numecs > tblend )
      tblend = position + numecs;
    }


/* stack1 - save states with only one out-transition to be processed later
 *
 * synopsis
 *   int statenum, sym, nextstate, deflink;
 *   stack1( statenum, sym, nextstate, deflink );
 *
 * if there's room for another state one the "one-transition" stack, the
 * state is pushed onto it, to be processed later by mk1tbl.  If there's
 * no room, we process the sucker right now.
 */

stack1( statenum, sym, nextstate, deflink )
int statenum, sym, nextstate, deflink;

    {
    if ( onesp >= ONE_STACK_SIZE )
      mk1tbl( statenum, sym, nextstate, deflink );

    else
      {
      ++onesp;
      onestate[onesp] = statenum;
      onesym[onesp] = sym;
      onenext[onesp] = nextstate;
      onedef[onesp] = deflink;
      }
    }


/* tbldiff - compute differences between two state tables
 *
 * synopsis
 *   int state[], pr, ext[];
 *   int tbldiff, numdifferences;
 *   numdifferences = tbldiff( state, pr, ext )
 *
 * "state" is the state array which is to be extracted from the pr'th
 * proto.  "pr" is both the number of the proto we are extracting from
 * and an index into the save area where we can find the proto's complete
 * state table.  Each entry in "state" which differs from the corresponding
 * entry of "pr" will appear in "ext".
 * Entries which are the same in both "state" and "pr" will be marked
 * as transitions to "SAME_TRANS" in "ext".  The total number of differences
 * between "state" and "pr" is returned as function value.  Note that this
 * number is "numecs" minus the number of "SAME_TRANS" entries in "ext".
 */

int tbldiff( state, pr, ext )
int state[], pr, ext[];

    {
    register int i, *sp = state, *ep = ext, *protp;
    register int numdiff = 0;

    protp = &protsave[numecs * (pr - 1)];

    for ( i = numecs; i > 0; --i )
      {
      if ( *++protp == *++sp )
          *++ep = SAME_TRANS;
      else
          {
          *++ep = *sp;
          ++numdiff;
          }
      }

    return ( numdiff );
    }

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