path: root/tblcmp.c

/* lexcmp - table compression routines */

/*
 * Copyright (c) University of California, 1987
 */

#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
 * homogenous or nearly homogenous (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 homogenous 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 ) );
    }


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

    {
    int i, j, k, numrows, *accset, nacc, *acc_array;
    char clower();

    /* *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 YYJAM %d\n", jamstate );
    printf( "#define YYJAMBASE %d\n", jambase );

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

#ifdef NOTDEF
/* unsupported code */
    if ( ! genftl )
	{ /* ratfor scanner */
	static char vardata[] = "%%%sdata %s/%d/\n";
	static char dindent[] = DATAINDENTSTR;
	static char arydecl[] = "integer %c(%d)\n";
	static char ary2decl[] = "integer %c(%d,%d)\n";

	skelout();

	if ( reject )
	    {
	    /* write out the pointers into the accepting lists for each state,
	     * and the accepting lists
	     */

	    /* alist needs to be lastdfa + 2 because we tell where a state's
	     * accepting list ends by checking the beginning of the next state,
	     * and there's an entry in alist for the default, "jam" pseudo-state
	     * (this latter entry is needed because states jam by making
	     * a transition to the state; see the flex skeleton.  By the way,
	     * I *think* we could get rid of the jam state entirely by
	     * slight modification of the skeleton ...)
	     */

	    printf( arydecl, ALIST, lastdfa + 2 );

	    printf( arydecl, ACCEPT, max( numas, 1 ) );
	    }

	else
	    printf( arydecl, ALIST, lastdfa + 1 );

	if ( useecs )
	    printf( arydecl, ECARRAY, CSIZE );
	if ( usemecs )
	    printf( arydecl, MATCHARRAY, numecs );

	if ( fulltbl )
	    {
	    printf( ary2decl, NEXTARRAY, lastdfa, numecs );
	    printf( vardata, dindent, "yyjam", 0 );
	    }

	else
	    {
	    printf( arydecl, BASEARRAY, lastdfa + numtemps );
	    printf( arydecl, DEFARRAY, lastdfa + numtemps );
	    printf( arydecl, NEXTARRAY, tblend );
	    printf( arydecl, CHECKARRAY, tblend );

	    printf( vardata, dindent, "yyjam", jambase );

	    /* the first template begins right after the default jam table,
	     * which itself begins right after the last dfa
	     */

	    printf( vardata, dindent, "yytmp", lastdfa + 2 );
	    }
	}
#endif NOTDEF

    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
	 */

	if ( genftl )
	    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];
		nacc = accsiz[i];

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

		for ( k = 1; k <= nacc; ++k )
		    {
		    mkdata( ACCEPT, j++, 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] = (int) dfaacc[i];
	
	acc_array[i] = 0; /* add (null) accepting number for jam state */
	}

    /* 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.
     */

    if ( genftl )
	{
	/* "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;

	printf( ((reject && numas > 126) || accnum > 127) ?
		ftl_short_decl : ftl_char_decl, ALIST, k );
	}

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

    if ( reject )
	/* add "cap" for the list */
	mkdata( ALIST, i + 1, acc_array[i] );

    dataend();

    if ( useecs )
	{
	/* write out equivalence classes */

	if ( genftl )
	    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( ECARRAY, i, 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 );
		}
	    }
	}

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

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

	if ( genftl )
	    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( MATCHARRAY, i, abs( tecbck[i] ) );
	    }

	dataend();
	}

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

	if ( genftl )
	    printf( tblend > 32766 ? 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( BASEARRAY, i, base[i] );
	    }

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

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

	dataend();

	if ( genftl )
	    printf( tblend > 32766 ? ftl_long_decl : ftl_short_decl,
		    DEFARRAY, total_states + 1 );

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

	dataend();

	if ( genftl )
	    printf( lastdfa > 32766 ? ftl_long_decl : ftl_short_decl,
		    NEXTARRAY, tblend + 1 );

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

	    mkdata( NEXTARRAY, i, nxt[i] );
	    }

	dataend();

	if ( genftl )
	    printf( lastdfa > 32766 ? ftl_long_decl : ftl_short_decl,
		    CHECKARRAY, tblend + 1 );

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

	    mkdata( CHECKARRAY, i, chk[i] );
	    }

	dataend();
	}

    skelout();

    /* copy remainder of input to output */

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


/* 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;
	}
    }


/* 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 accomodate 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];

    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 ( genftl )
	skelout();

    if ( fulltbl )
	{
	if ( genftl )
	    {
	    /* 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 );

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

    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;
		}
	    }

	numsnpairs = numsnpairs + totaltrans;

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

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

	if ( fulltbl )
	    {
	    if ( genftl )
		{
		/* supply array's 0-element */
		mk2data( NEXTARRAY, 0, 0, 0 );

		for ( i = 1; i <= numecs; ++i )
		    mk2data( NEXTARRAY, 0, 0, state[i] );

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

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

	    else
		{
		for ( i = 1; i <= numecs; ++i )
		    mk2data( NEXTARRAY, ds, i, state[i] );
		}
	    }

	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 );
	    }
	}

    if ( fulltbl )
	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();
	}
    }


/* 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 );
    }