fatbase

gen.c (37251B)

---

 /*	$OpenBSD: gen.c,v 1.11 2004/02/03 21:20:17 espie Exp $	*/
 
 /* gen - actual generation (writing) of flex scanners */
 
 /*-
  * Copyright (c) 1990 The Regents of the University of California.
  * All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Vern Paxson.
  * 
  * 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.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * Neither the name of the University nor the names of its contributors
  * may be used to endorse or promote products derived from this software
  * without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE.
  */
 
 /* $Header: /cvs/src/usr.bin/lex/gen.c,v 1.11 2004/02/03 21:20:17 espie Exp $ */
 
 #include "flexdef.h"
 
 
 /* declare functions that have forward references */
 
 void gen_next_state PROTO((int));
 void genecs PROTO((void));
 void indent_put2s PROTO((char [], char []));
 void indent_puts PROTO((char []));
 
 
 static int indent_level = 0; /* each level is 8 spaces */
 
 #define indent_up() (++indent_level)
 #define indent_down() (--indent_level)
 #define set_indent(indent_val) indent_level = indent_val
 
 /* Almost everything is done in terms of arrays starting at 1, so provide
  * a null entry for the zero element of all C arrays.  (The exception
  * to this is that the fast table representation generally uses the
  * 0 elements of its arrays, too.)
  */
 static char C_int_decl[] = "static yyconst int %s[%d] =\n    {   0,\n";
 static char C_short_decl[] = "static yyconst short int %s[%d] =\n    {   0,\n";
 static char C_long_decl[] = "static yyconst long int %s[%d] =\n    {   0,\n";
 static char C_state_decl[] =
 	"static yyconst yy_state_type %s[%d] =\n    {   0,\n";
 
 
 /* Indent to the current level. */
 
 void do_indent()
 	{
 	int i = indent_level * 8;
 
 	while ( i >= 8 )
 		{
 		outc( '\t' );
 		i -= 8;
 		}
 
 	while ( i > 0 )
 		{
 		outc( ' ' );
 		--i;
 		}
 	}
 
 
 /* Generate the code to keep backing-up information. */
 
 void gen_backing_up()
 	{
 	if ( reject || num_backing_up == 0 )
 		return;
 
 	if ( fullspd )
 		indent_puts( "if ( yy_current_state[-1].yy_nxt )" );
 	else
 		indent_puts( "if ( yy_accept[yy_current_state] )" );
 
 	indent_up();
 	indent_puts( "{" );
 	indent_puts( "yy_last_accepting_state = yy_current_state;" );
 	indent_puts( "yy_last_accepting_cpos = yy_cp;" );
 	indent_puts( "}" );
 	indent_down();
 	}
 
 
 /* Generate the code to perform the backing up. */
 
 void gen_bu_action()
 	{
 	if ( reject || num_backing_up == 0 )
 		return;
 
 	set_indent( 3 );
 
 	indent_puts( "case 0: /* must back up */" );
 	indent_puts( "/* undo the effects of YY_DO_BEFORE_ACTION */" );
 	indent_puts( "*yy_cp = yy_hold_char;" );
 
 	if ( fullspd || fulltbl )
 		indent_puts( "yy_cp = yy_last_accepting_cpos + 1;" );
 	else
 		/* Backing-up info for compressed tables is taken \after/
 		 * yy_cp has been incremented for the next state.
 		 */
 		indent_puts( "yy_cp = yy_last_accepting_cpos;" );
 
 	indent_puts( "yy_current_state = yy_last_accepting_state;" );
 	indent_puts( "goto yy_find_action;" );
 	outc( '\n' );
 
 	set_indent( 0 );
 	}
 
 
 /* genctbl - generates full speed compressed transition table */
 
 void genctbl()
 	{
 	int i;
 	int end_of_buffer_action = num_rules + 1;
 
 	/* Table of verify for transition and offset to next state. */
 	out_dec( "static yyconst struct yy_trans_info yy_transition[%d] =\n",
 		tblend + numecs + 1 );
 	outn( "    {" );
 
 	/* 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 of current state)].  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.
 	 */
 
 	/* We need to have room in nxt/chk for two more 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.
 	 */
 
 	while ( tblend + 2 >= current_max_xpairs )
 		expand_nxt_chk();
 
 	while ( lastdfa + 1 >= current_max_dfas )
 		increase_max_dfas();
 
 	base[lastdfa + 1] = tblend + 2;
 	nxt[tblend + 1] = end_of_buffer_action;
 	chk[tblend + 1] = numecs + 1;
 	chk[tblend + 2] = 1; /* anything but EOB */
 
 	/* So that "make test" won't show arb. differences. */
 	nxt[tblend + 2] = 0;
 
 	/* Make sure every state has an end-of-buffer transition and an
 	 * action #.
 	 */
 	for ( i = 0; i <= lastdfa; ++i )
 		{
 		int anum = dfaacc[i].dfaacc_state;
 		int offset = base[i];
 
 		chk[offset] = EOB_POSITION;
 		chk[offset - 1] = ACTION_POSITION;
 		nxt[offset - 1] = anum;	/* action number */
 		}
 
 	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] );
 
 	outn( "    };\n" );
 
 	/* Table of pointers to start states. */
 	out_dec(
 	"static yyconst struct yy_trans_info *yy_start_state_list[%d] =\n",
 		lastsc * 2 + 1 );
 	outn( "    {" );	/* } so vi doesn't get confused */
 
 	for ( i = 0; i <= lastsc * 2; ++i )
 		out_dec( "    &yy_transition[%d],\n", base[i] );
 
 	dataend();
 
 	if ( useecs )
 		genecs();
 	}
 
 
 /* Generate equivalence-class tables. */
 
 void genecs()
 	{
 	int i, j;
 	int numrows;
 
 	out_str_dec( C_int_decl, "yy_ec", csize );
 
 	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 / 8;
 
 		for ( j = 0; j < numrows; ++j )
 			{
 			for ( i = j; i < csize; i = i + numrows )
 				{
 				fprintf( stderr, "%4s = %-2d",
 					readable_form( i ), ecgroup[i] );
 
 				putc( ' ', stderr );
 				}
 
 			putc( '\n', stderr );
 			}
 		}
 	}
 
 
 /* Generate the code to find the action number. */
 
 void gen_find_action()
 	{
 	if ( fullspd )
 		indent_puts( "yy_act = yy_current_state[-1].yy_nxt;" );
 
 	else if ( fulltbl )
 		indent_puts( "yy_act = yy_accept[yy_current_state];" );
 
 	else if ( reject )
 		{
 		indent_puts( "yy_current_state = *--yy_state_ptr;" );
 		indent_puts( "yy_lp = yy_accept[yy_current_state];" );
 
 		outn(
 		"find_rule: /* we branch to this label when backing up */" );
 
 		indent_puts(
 		"for ( ; ; ) /* until we find what rule we matched */" );
 
 		indent_up();
 
 		indent_puts( "{" );
 
 		indent_puts(
 		"if ( yy_lp && yy_lp < yy_accept[yy_current_state + 1] )" );
 		indent_up();
 		indent_puts( "{" );
 		indent_puts( "yy_act = yy_acclist[yy_lp];" );
 
 		if ( variable_trailing_context_rules )
 			{
 			indent_puts( "if ( yy_act & YY_TRAILING_HEAD_MASK ||" );
 			indent_puts( "     yy_looking_for_trail_begin )" );
 			indent_up();
 			indent_puts( "{" );
 
 			indent_puts(
 				"if ( yy_act == yy_looking_for_trail_begin )" );
 			indent_up();
 			indent_puts( "{" );
 			indent_puts( "yy_looking_for_trail_begin = 0;" );
 			indent_puts( "yy_act &= ~YY_TRAILING_HEAD_MASK;" );
 			indent_puts( "break;" );
 			indent_puts( "}" );
 			indent_down();
 
 			indent_puts( "}" );
 			indent_down();
 
 			indent_puts( "else if ( yy_act & YY_TRAILING_MASK )" );
 			indent_up();
 			indent_puts( "{" );
 			indent_puts(
 		"yy_looking_for_trail_begin = yy_act & ~YY_TRAILING_MASK;" );
 			indent_puts(
 		"yy_looking_for_trail_begin |= YY_TRAILING_HEAD_MASK;" );
 
 			if ( real_reject )
 				{
 				/* Remember matched text in case we back up
 				 * due to REJECT.
 				 */
 				indent_puts( "yy_full_match = yy_cp;" );
 				indent_puts( "yy_full_state = yy_state_ptr;" );
 				indent_puts( "yy_full_lp = yy_lp;" );
 				}
 
 			indent_puts( "}" );
 			indent_down();
 
 			indent_puts( "else" );
 			indent_up();
 			indent_puts( "{" );
 			indent_puts( "yy_full_match = yy_cp;" );
 			indent_puts( "yy_full_state = yy_state_ptr;" );
 			indent_puts( "yy_full_lp = yy_lp;" );
 			indent_puts( "break;" );
 			indent_puts( "}" );
 			indent_down();
 
 			indent_puts( "++yy_lp;" );
 			indent_puts( "goto find_rule;" );
 			}
 
 		else
 			{
 			/* Remember matched text in case we back up due to
 			 * trailing context plus REJECT.
 			 */
 			indent_up();
 			indent_puts( "{" );
 			indent_puts( "yy_full_match = yy_cp;" );
 			indent_puts( "break;" );
 			indent_puts( "}" );
 			indent_down();
 			}
 
 		indent_puts( "}" );
 		indent_down();
 
 		indent_puts( "--yy_cp;" );
 
 		/* We could consolidate the following two lines with those at
 		 * the beginning, but at the cost of complaints that we're
 		 * branching inside a loop.
 		 */
 		indent_puts( "yy_current_state = *--yy_state_ptr;" );
 		indent_puts( "yy_lp = yy_accept[yy_current_state];" );
 
 		indent_puts( "}" );
 
 		indent_down();
 		}
 
 	else
 		{ /* compressed */
 		indent_puts( "yy_act = yy_accept[yy_current_state];" );
 
 		if ( interactive && ! reject )
 			{
 			/* Do the guaranteed-needed backing up to figure out
 			 * the match.
 			 */
 			indent_puts( "if ( yy_act == 0 )" );
 			indent_up();
 			indent_puts( "{ /* have to back up */" );
 			indent_puts( "yy_cp = yy_last_accepting_cpos;" );
 			indent_puts(
 				"yy_current_state = yy_last_accepting_state;" );
 			indent_puts( "yy_act = yy_accept[yy_current_state];" );
 			indent_puts( "}" );
 			indent_down();
 			}
 		}
 	}
 
 
 /* genftbl - generate full transition table */
 
 void genftbl()
 	{
 	int i;
 	int end_of_buffer_action = num_rules + 1;
 
 	out_str_dec( long_align ? C_long_decl : C_short_decl,
 		"yy_accept", lastdfa + 1 );
 
 	dfaacc[end_of_buffer_state].dfaacc_state = end_of_buffer_action;
 
 	for ( i = 1; i <= lastdfa; ++i )
 		{
 		int anum = dfaacc[i].dfaacc_state;
 
 		mkdata( anum );
 
 		if ( trace && anum )
 			fprintf( stderr, _( "state # %d accepts: [%d]\n" ),
 				i, anum );
 		}
 
 	dataend();
 
 	if ( useecs )
 		genecs();
 
 	/* Don't have to dump the actual full table entries - they were
 	 * created on-the-fly.
 	 */
 	}
 
 
 /* Generate the code to find the next compressed-table state. */
 
 void gen_next_compressed_state( char_map )
 char *char_map;
 	{
 	indent_put2s( "register YY_CHAR yy_c = %s;", char_map );
 
 	/* Save the backing-up info \before/ computing the next state
 	 * because we always compute one more state than needed - we
 	 * always proceed until we reach a jam state
 	 */
 	gen_backing_up();
 
 	indent_puts(
 "while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )" );
 	indent_up();
 	indent_puts( "{" );
 	indent_puts( "yy_current_state = (int) yy_def[yy_current_state];" );
 
 	if ( usemecs )
 		{
 		/* We've arrange it so that templates are never chained
 		 * to one another.  This means we can afford to make a
 		 * very simple test to see if we need to convert to
 		 * yy_c's meta-equivalence class without worrying
 		 * about erroneously looking up the meta-equivalence
 		 * class twice
 		 */
 		do_indent();
 
 		/* lastdfa + 2 is the beginning of the templates */
 		out_dec( "if ( yy_current_state >= %d )\n", lastdfa + 2 );
 
 		indent_up();
 		indent_puts( "yy_c = yy_meta[(unsigned int) yy_c];" );
 		indent_down();
 		}
 
 	indent_puts( "}" );
 	indent_down();
 
 	indent_puts(
 "yy_current_state = yy_nxt[yy_base[yy_current_state] + (unsigned int) yy_c];" );
 	}
 
 
 /* Generate the code to find the next match. */
 
 void gen_next_match()
 	{
 	/* NOTE - changes in here should be reflected in gen_next_state() and
 	 * gen_NUL_trans().
 	 */
 	char *char_map = useecs ?
 				"yy_ec[YY_SC_TO_UI(*yy_cp)]" :
 				"YY_SC_TO_UI(*yy_cp)";
 
 	char *char_map_2 = useecs ?
 				"yy_ec[YY_SC_TO_UI(*++yy_cp)]" :
 				"YY_SC_TO_UI(*++yy_cp)";
 
 	if ( fulltbl )
 		{
 		indent_put2s(
 	"while ( (yy_current_state = yy_nxt[yy_current_state][%s]) > 0 )",
 				char_map );
 
 		indent_up();
 
 		if ( num_backing_up > 0 )
 			{
 			indent_puts( "{" );	/* } for vi */
 			gen_backing_up();
 			outc( '\n' );
 			}
 
 		indent_puts( "++yy_cp;" );
 
 		if ( num_backing_up > 0 )
 			/* { for vi */
 			indent_puts( "}" );
 
 		indent_down();
 
 		outc( '\n' );
 		indent_puts( "yy_current_state = -yy_current_state;" );
 		}
 
 	else if ( fullspd )
 		{
 		indent_puts( "{" );	/* } for vi */
 		indent_puts(
 		"register yyconst struct yy_trans_info *yy_trans_info;\n" );
 		indent_puts( "register YY_CHAR yy_c;\n" );
 		indent_put2s( "for ( yy_c = %s;", char_map );
 		indent_puts(
 	"      (yy_trans_info = &yy_current_state[(unsigned int) yy_c])->" );
 		indent_puts( "yy_verify == yy_c;" );
 		indent_put2s( "      yy_c = %s )", char_map_2 );
 
 		indent_up();
 
 		if ( num_backing_up > 0 )
 			indent_puts( "{" );	/* } for vi */
 
 		indent_puts( "yy_current_state += yy_trans_info->yy_nxt;" );
 
 		if ( num_backing_up > 0 )
 			{
 			outc( '\n' );
 			gen_backing_up();	/* { for vi */
 			indent_puts( "}" );
 			}
 
 		indent_down();	/* { for vi */
 		indent_puts( "}" );
 		}
 
 	else
 		{ /* compressed */
 		indent_puts( "do" );
 
 		indent_up();
 		indent_puts( "{" );	/* } for vi */
 
 		gen_next_state( false );
 
 		indent_puts( "++yy_cp;" );
 
 		/* { for vi */
 		indent_puts( "}" );
 		indent_down();
 
 		do_indent();
 
 		if ( interactive )
 			out_dec( "while ( yy_base[yy_current_state] != %d );\n",
 				jambase );
 		else
 			out_dec( "while ( yy_current_state != %d );\n",
 				jamstate );
 
 		if ( ! reject && ! interactive )
 			{
 			/* Do the guaranteed-needed backing up to figure out
 			 * the match.
 			 */
 			indent_puts( "yy_cp = yy_last_accepting_cpos;" );
 			indent_puts(
 				"yy_current_state = yy_last_accepting_state;" );
 			}
 		}
 	}
 
 
 /* Generate the code to find the next state. */
 
 void gen_next_state( worry_about_NULs )
 int worry_about_NULs;
 	{ /* NOTE - changes in here should be reflected in gen_next_match() */
 	char char_map[256];
 
 	if ( worry_about_NULs && ! nultrans )
 		{
 		if ( useecs )
 			(void) snprintf( char_map, sizeof char_map,
 				"(*yy_cp ? yy_ec[YY_SC_TO_UI(*yy_cp)] : %d)",
 					NUL_ec );
 		else
 			(void) snprintf( char_map, sizeof char_map,
 				"(*yy_cp ? YY_SC_TO_UI(*yy_cp) : %d)", NUL_ec );
 		}
 
 	else
 		strlcpy( char_map, useecs ?
 			"yy_ec[YY_SC_TO_UI(*yy_cp)]" : "YY_SC_TO_UI(*yy_cp)",
 			sizeof char_map );
 
 	if ( worry_about_NULs && nultrans )
 		{
 		if ( ! fulltbl && ! fullspd )
 			/* Compressed tables back up *before* they match. */
 			gen_backing_up();
 
 		indent_puts( "if ( *yy_cp )" );
 		indent_up();
 		indent_puts( "{" );	/* } for vi */
 		}
 
 	if ( fulltbl )
 		indent_put2s(
 			"yy_current_state = yy_nxt[yy_current_state][%s];", 
 				char_map );
 
 	else if ( fullspd )
 		indent_put2s(
 			"yy_current_state += yy_current_state[%s].yy_nxt;",
 				char_map );
 
 	else
 		gen_next_compressed_state( char_map );
 
 	if ( worry_about_NULs && nultrans )
 		{
 		/* { for vi */
 		indent_puts( "}" );
 		indent_down();
 		indent_puts( "else" );
 		indent_up();
 		indent_puts(
 			"yy_current_state = yy_NUL_trans[yy_current_state];" );
 		indent_down();
 		}
 
 	if ( fullspd || fulltbl )
 		gen_backing_up();
 
 	if ( reject )
 		indent_puts( "*yy_state_ptr++ = yy_current_state;" );
 	}
 
 
 /* Generate the code to make a NUL transition. */
 
 void gen_NUL_trans()
 	{ /* NOTE - changes in here should be reflected in gen_next_match() */
 	/* Only generate a definition for "yy_cp" if we'll generate code
 	 * that uses it.  Otherwise lint and the like complain.
 	 */
 	int need_backing_up = (num_backing_up > 0 && ! reject);
 
 	if ( need_backing_up && (! nultrans || fullspd || fulltbl) )
 		/* We're going to need yy_cp lying around for the call
 		 * below to gen_backing_up().
 		 */
 		indent_puts( "register char *yy_cp = yy_c_buf_p;" );
 
 	outc( '\n' );
 
 	if ( nultrans )
 		{
 		indent_puts(
 			"yy_current_state = yy_NUL_trans[yy_current_state];" );
 		indent_puts( "yy_is_jam = (yy_current_state == 0);" );
 		}
 
 	else if ( fulltbl )
 		{
 		do_indent();
 		out_dec( "yy_current_state = yy_nxt[yy_current_state][%d];\n",
 			NUL_ec );
 		indent_puts( "yy_is_jam = (yy_current_state <= 0);" );
 		}
 
 	else if ( fullspd )
 		{
 		do_indent();
 		out_dec( "register int yy_c = %d;\n", NUL_ec );
 
 		indent_puts(
 		"register yyconst struct yy_trans_info *yy_trans_info;\n" );
 		indent_puts(
 		"yy_trans_info = &yy_current_state[(unsigned int) yy_c];" );
 		indent_puts( "yy_current_state += yy_trans_info->yy_nxt;" );
 
 		indent_puts(
 			"yy_is_jam = (yy_trans_info->yy_verify != yy_c);" );
 		}
 
 	else
 		{
 		char NUL_ec_str[20];
 
 		(void) snprintf( NUL_ec_str, sizeof NUL_ec_str, "%d", NUL_ec );
 		gen_next_compressed_state( NUL_ec_str );
 
 		do_indent();
 		out_dec( "yy_is_jam = (yy_current_state == %d);\n", jamstate );
 
 		if ( reject )
 			{
 			/* Only stack this state if it's a transition we
 			 * actually make.  If we stack it on a jam, then
 			 * the state stack and yy_c_buf_p get out of sync.
 			 */
 			indent_puts( "if ( ! yy_is_jam )" );
 			indent_up();
 			indent_puts( "*yy_state_ptr++ = yy_current_state;" );
 			indent_down();
 			}
 		}
 
 	/* If we've entered an accepting state, back up; note that
 	 * compressed tables have *already* done such backing up, so
 	 * we needn't bother with it again.
 	 */
 	if ( need_backing_up && (fullspd || fulltbl) )
 		{
 		outc( '\n' );
 		indent_puts( "if ( ! yy_is_jam )" );
 		indent_up();
 		indent_puts( "{" );
 		gen_backing_up();
 		indent_puts( "}" );
 		indent_down();
 		}
 	}
 
 
 /* Generate the code to find the start state. */
 
 void gen_start_state()
 	{
 	if ( fullspd )
 		{
 		if ( bol_needed )
 			{
 			indent_puts(
 	"yy_current_state = yy_start_state_list[yy_start + YY_AT_BOL()];" );
 			}
 		else
 			indent_puts(
 			"yy_current_state = yy_start_state_list[yy_start];" );
 		}
 
 	else
 		{
 		indent_puts( "yy_current_state = yy_start;" );
 
 		if ( bol_needed )
 			indent_puts( "yy_current_state += YY_AT_BOL();" );
 
 		if ( reject )
 			{
 			/* Set up for storing up states. */
 			indent_puts( "yy_state_ptr = yy_state_buf;" );
 			indent_puts( "*yy_state_ptr++ = yy_current_state;" );
 			}
 		}
 	}
 
 
 /* gentabs - generate data statements for the transition tables */
 
 void gentabs()
 	{
 	int i, j, k, *accset, nacc, *acc_array, total_states;
 	int end_of_buffer_action = num_rules + 1;
 
 	acc_array = allocate_integer_array( current_max_dfas );
 	nummt = 0;
 
 	/* The compressed table format jams by entering the "jam state",
 	 * losing information about the previous state in the process.
 	 * In order to recover the previous state, we effectively need
 	 * to keep backing-up information.
 	 */
 	++num_backing_up;
 
 	if ( reject )
 		{
 		/* Write out accepting list and pointer list.
 		 *
 		 * First we generate the "yy_acclist" array.  In the process,
 		 * we compute the indices that will go into the "yy_accept"
 		 * array, and save the indices in the dfaacc array.
 		 */
 		int EOB_accepting_list[2];
 
 		/* Set up accepting structures for the End Of Buffer state. */
 		EOB_accepting_list[0] = 0;
 		EOB_accepting_list[1] = end_of_buffer_action;
 		accsiz[end_of_buffer_state] = 1;
 		dfaacc[end_of_buffer_state].dfaacc_set = EOB_accepting_list;
 
 		out_str_dec( long_align ? C_long_decl : C_short_decl,
 			"yy_acclist", MAX( numas, 1 ) + 1 );
 
 		j = 1;	/* index into "yy_acclist" 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 )
 					{
 					int accnum = accset[k];
 
 					++j;
 
 					if ( variable_trailing_context_rules &&
 					  ! (accnum & YY_TRAILING_HEAD_MASK) &&
 					   accnum > 0 && accnum <= num_rules &&
 					  rule_type[accnum] == RULE_VARIABLE )
 						{
 						/* Special hack to flag
 						 * accepting number as part
 						 * of trailing context rule.
 						 */
 						accnum |= YY_TRAILING_MASK;
 						}
 
 					mkdata( accnum );
 
 					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
 		{
 		dfaacc[end_of_buffer_state].dfaacc_state = end_of_buffer_action;
 
 		for ( i = 1; i <= lastdfa; ++i )
 			acc_array[i] = dfaacc[i].dfaacc_state;
 
 		/* add accepting number for jam state */
 		acc_array[i] = 0;
 		}
 
 	/* Spit out "yy_accept" array.  If we're doing "reject", it'll be
 	 * pointers into the "yy_acclist" array.  Otherwise it's actual
 	 * accepting numbers.  In either case, we just dump the numbers.
 	 */
 
 	/* "lastdfa + 2" is the size of "yy_accept"; includes room for C 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;
 
 	out_str_dec( long_align ? C_long_decl : C_short_decl, "yy_accept", k );
 
 	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 );
 
 		out_str_dec( C_int_decl, "yy_meta", numecs + 1 );
 
 		for ( i = 1; i <= numecs; ++i )
 			{
 			if ( trace )
 				fprintf( stderr, "%d = %d\n",
 					i, ABS( tecbck[i] ) );
 
 			mkdata( ABS( tecbck[i] ) );
 			}
 
 		dataend();
 		}
 
 	total_states = lastdfa + numtemps;
 
 	out_str_dec( (tblend >= MAX_SHORT || long_align) ?
 			C_long_decl : C_short_decl,
 		"yy_base", total_states + 1 );
 
 	for ( i = 1; i <= lastdfa; ++i )
 		{
 		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();
 
 	out_str_dec( (total_states >= MAX_SHORT || long_align) ?
 			C_long_decl : C_short_decl,
 		"yy_def", total_states + 1 );
 
 	for ( i = 1; i <= total_states; ++i )
 		mkdata( def[i] );
 
 	dataend();
 
 	out_str_dec( (total_states >= MAX_SHORT || long_align) ?
 			C_long_decl : C_short_decl,
 		"yy_nxt", tblend + 1 );
 
 	for ( i = 1; i <= tblend; ++i )
 		{
 		/* Note, the order of the following test is important.
 		 * If chk[i] is 0, then nxt[i] is undefined.
 		 */
 		if ( chk[i] == 0 || nxt[i] == 0 )
 			nxt[i] = jamstate;	/* new state is the JAM state */
 
 		mkdata( nxt[i] );
 		}
 
 	dataend();
 
 	out_str_dec( (total_states >= MAX_SHORT || long_align) ?
 			C_long_decl : C_short_decl,
 		"yy_chk", tblend + 1 );
 
 	for ( i = 1; i <= tblend; ++i )
 		{
 		if ( chk[i] == 0 )
 			++nummt;
 
 		mkdata( chk[i] );
 		}
 
 	dataend();
 	free(acc_array);
 	}
 
 
 /* Write out a formatted string (with a secondary string argument) at the
  * current indentation level, adding a final newline.
  */
 
 void indent_put2s( fmt, arg )
 char fmt[], arg[];
 	{
 	do_indent();
 	out_str( fmt, arg );
 	outn( "" );
 	}
 
 
 /* Write out a string at the current indentation level, adding a final
  * newline.
  */
 
 void indent_puts( str )
 char str[];
 	{
 	do_indent();
 	outn( str );
 	}
 
 
 /* make_tables - generate transition tables and finishes generating output file
  */
 
 void make_tables()
 	{
 	int i;
 	int did_eof_rule = false;
 
 	skelout();
 
 	/* First, take care of YY_DO_BEFORE_ACTION depending on yymore
 	 * being used.
 	 */
 	set_indent( 1 );
 
 	if ( yymore_used && ! yytext_is_array )
 		{
 		indent_puts( "yytext_ptr -= yy_more_len; \\" );
 		indent_puts( "yyleng = (int) (yy_cp - yytext_ptr); \\" );
 		}
 
 	else
 		indent_puts( "yyleng = (int) (yy_cp - yy_bp); \\" );
 
 	/* Now also deal with copying yytext_ptr to yytext if needed. */
 	skelout();
 	if ( yytext_is_array )
 		{
 		if ( yymore_used )
 			indent_puts(
 				"if ( yyleng + yy_more_offset >= YYLMAX ) \\" );
 		else
 			indent_puts( "if ( yyleng >= YYLMAX ) \\" );
 
 		indent_up();
 		indent_puts(
 		"YY_FATAL_ERROR( \"token too large, exceeds YYLMAX\" ); \\" );
 		indent_down();
 
 		if ( yymore_used )
 			{
 			indent_puts(
 "yy_flex_strncpy( &yytext[yy_more_offset], yytext_ptr, yyleng + 1 ); \\" );
 			indent_puts( "yyleng += yy_more_offset; \\" );
 			indent_puts(
 				"yy_prev_more_offset = yy_more_offset; \\" );
 			indent_puts( "yy_more_offset = 0; \\" );
 			}
 		else
 			{
 			indent_puts(
 		"yy_flex_strncpy( yytext, yytext_ptr, yyleng + 1 ); \\" );
 			}
 		}
 
 	set_indent( 0 );
 
 	skelout();
 
 
 	out_dec( "#define YY_NUM_RULES %d\n", num_rules );
 	out_dec( "#define YY_END_OF_BUFFER %d\n", num_rules + 1 );
 
 	if ( fullspd )
 		{
 		/* Need to define the transet type as a size large
 		 * enough to hold the biggest offset.
 		 */
 		int total_table_size = tblend + numecs + 1;
 		char *trans_offset_type =
 			(total_table_size >= MAX_SHORT || long_align) ?
 				"long" : "short";
 
 		set_indent( 0 );
 		indent_puts( "struct yy_trans_info" );
 		indent_up();
 		indent_puts( "{" ); 	/* } for vi */
 
 		if ( long_align )
 			indent_puts( "long yy_verify;" );
 		else
 			indent_puts( "short yy_verify;" );
 
 		/* In cases where its sister yy_verify *is* a "yes, there is
 		 * a transition", yy_nxt is the offset (in records) to the
 		 * next state.  In most cases where there is no transition,
 		 * the value of yy_nxt is irrelevant.  If yy_nxt is the -1th
 		 * record of a state, though, then yy_nxt is the action number
 		 * for that state.
 		 */
 
 		indent_put2s( "%s yy_nxt;", trans_offset_type );
 		indent_puts( "};" );
 		indent_down();
 		}
 
 	if ( fullspd )
 		genctbl();
 	else if ( fulltbl )
 		genftbl();
 	else
 		gentabs();
 
 	/* Definitions for backing up.  We don't need them if REJECT
 	 * is being used because then we use an alternative backin-up
 	 * technique instead.
 	 */
 	if ( num_backing_up > 0 && ! reject )
 		{
 		if ( ! C_plus_plus )
 			{
 			indent_puts(
 			"static yy_state_type yy_last_accepting_state;" );
 			indent_puts(
 				"static char *yy_last_accepting_cpos;\n" );
 			}
 		}
 
 	if ( nultrans )
 		{
 		out_str_dec( C_state_decl, "yy_NUL_trans", lastdfa + 1 );
 
 		for ( i = 1; i <= lastdfa; ++i )
 			{
 			if ( fullspd )
 				out_dec( "    &yy_transition[%d],\n", base[i] );
 			else
 				mkdata( nultrans[i] );
 			}
 
 		dataend();
 		}
 
 	if ( ddebug )
 		{ /* Spit out table mapping rules to line numbers. */
 		if ( ! C_plus_plus )
 			{
 			indent_puts( "extern int yy_flex_debug;" );
 			indent_puts( "int yy_flex_debug = 1;\n" );
 			}
 
 		out_str_dec( long_align ? C_long_decl : C_short_decl,
 			"yy_rule_linenum", num_rules );
 		for ( i = 1; i < num_rules; ++i )
 			mkdata( rule_linenum[i] );
 		dataend();
 		}
 
 	if ( reject )
 		{
 		/* Declare state buffer variables. */
 		if ( ! C_plus_plus )
 			{
 			outn(
 	"static yy_state_type yy_state_buf[YY_BUF_SIZE + 2], *yy_state_ptr;" );
 			outn( "static char *yy_full_match;" );
 			outn( "static int yy_lp;" );
 			}
 
 		if ( variable_trailing_context_rules )
 			{
 			if ( ! C_plus_plus )
 				{
 				outn(
 				"static int yy_looking_for_trail_begin = 0;" );
 				outn( "static int yy_full_lp;" );
 				outn( "static int *yy_full_state;" );
 				}
 
 			out_hex( "#define YY_TRAILING_MASK 0x%x\n",
 				(unsigned int) YY_TRAILING_MASK );
 			out_hex( "#define YY_TRAILING_HEAD_MASK 0x%x\n",
 				(unsigned int) YY_TRAILING_HEAD_MASK );
 			}
 
 		outn( "#define REJECT \\" );
 		outn( "{ \\" );		/* } for vi */
 		outn(
 	"*yy_cp = yy_hold_char; /* undo effects of setting up yytext */ \\" );
 		outn(
 	"yy_cp = yy_full_match; /* restore poss. backed-over text */ \\" );
 
 		if ( variable_trailing_context_rules )
 			{
 			outn(
 		"yy_lp = yy_full_lp; /* restore orig. accepting pos. */ \\" );
 			outn(
 		"yy_state_ptr = yy_full_state; /* restore orig. state */ \\" );
 			outn(
 	"yy_current_state = *yy_state_ptr; /* restore curr. state */ \\" );
 			}
 
 		outn( "++yy_lp; \\" );
 		outn( "goto find_rule; \\" );
 		/* { for vi */
 		outn( "}" );
 		}
 
 	else
 		{
 		outn(
 		"/* The intent behind this definition is that it'll catch" );
 		outn( " * any uses of REJECT which flex missed." );
 		outn( " */" );
 		outn( "#define REJECT reject_used_but_not_detected" );
 		}
 
 	if ( yymore_used )
 		{
 		if ( ! C_plus_plus )
 			{
 			if ( yytext_is_array )
 				{
 				indent_puts( "static int yy_more_offset = 0;" );
 				indent_puts(
 					"static int yy_prev_more_offset = 0;" );
 				}
 			else
 				{
 				indent_puts( "static int yy_more_flag = 0;" );
 				indent_puts( "static int yy_more_len = 0;" );
 				}
 			}
 
 		if ( yytext_is_array )
 			{
 			indent_puts(
 	"#define yymore() (yy_more_offset = yy_flex_strlen( yytext ))" );
 			indent_puts( "#define YY_NEED_STRLEN" );
 			indent_puts( "#define YY_MORE_ADJ 0" );
 			indent_puts( "#define YY_RESTORE_YY_MORE_OFFSET \\" );
 			indent_up();
 			indent_puts( "{ \\" );
 			indent_puts( "yy_more_offset = yy_prev_more_offset; \\" );
 			indent_puts( "yyleng -= yy_more_offset; \\" );
 			indent_puts( "}" );
 			indent_down();
 			}
 		else
 			{
 			indent_puts( "#define yymore() (yy_more_flag = 1)" );
 			indent_puts( "#define YY_MORE_ADJ yy_more_len" );
 			indent_puts( "#define YY_RESTORE_YY_MORE_OFFSET" );
 			}
 		}
 
 	else
 		{
 		indent_puts( "#define yymore() yymore_used_but_not_detected" );
 		indent_puts( "#define YY_MORE_ADJ 0" );
 		indent_puts( "#define YY_RESTORE_YY_MORE_OFFSET" );
 		}
 
 	if ( ! C_plus_plus )
 		{
 		if ( yytext_is_array )
 			{
 			outn( "#ifndef YYLMAX" );
 			outn( "#define YYLMAX 8192" );
 			outn( "#endif\n" );
 			outn( "char yytext[YYLMAX];" );
 			outn( "char *yytext_ptr;" );
 			}
 
 		else
 			outn( "char *yytext;" );
 		}
 
 	out( &action_array[defs1_offset] );
 
 	line_directive_out( stdout, 0 );
 
 	skelout();
 
 	if ( ! C_plus_plus )
 		{
 		if ( use_read )
 			{
 			outn(
 "\tif ( (result = read( fileno(yyin), (char *) buf, max_size )) < 0 ) \\" );
 			outn(
 		"\t\tYY_FATAL_ERROR( \"input in flex scanner failed\" );" );
 			}
 
 		else
 			{
 			outn(
 			"\tif ( yy_current_buffer->yy_is_interactive ) \\" );
 			outn( "\t\t{ \\" );
 			outn( "\t\tint c = '*', n; \\" );
 			outn( "\t\tfor ( n = 0; n < max_size && \\" );
 	outn( "\t\t\t     (c = getc( yyin )) != EOF && c != '\\n'; ++n ) \\" );
 			outn( "\t\t\tbuf[n] = (char) c; \\" );
 			outn( "\t\tif ( c == '\\n' ) \\" );
 			outn( "\t\t\tbuf[n++] = (char) c; \\" );
 			outn( "\t\tif ( c == EOF && ferror( yyin ) ) \\" );
 			outn(
 	"\t\t\tYY_FATAL_ERROR( \"input in flex scanner failed\" ); \\" );
 			outn( "\t\tresult = n; \\" );
 			outn( "\t\t} \\" );
 			outn(
 	"\telse if ( ((result = fread( buf, 1, max_size, yyin )) == 0) \\" );
 			outn( "\t\t  && ferror( yyin ) ) \\" );
 			outn(
 		"\t\tYY_FATAL_ERROR( \"input in flex scanner failed\" );" );
 			}
 		}
 
 	skelout();
 
 	indent_puts( "#define YY_RULE_SETUP \\" );
 	indent_up();
 	if ( bol_needed )
 		{
 		indent_puts( "if ( yyleng > 0 ) \\" );
 		indent_up();
 		indent_puts( "yy_current_buffer->yy_at_bol = \\" );
 		indent_puts( "\t\t(yytext[yyleng - 1] == '\\n'); \\" );
 		indent_down();
 		}
 	indent_puts( "YY_USER_ACTION" );
 	indent_down();
 
 	skelout();
 
 	/* Copy prolog to output file. */
 	out( &action_array[prolog_offset] );
 
 	line_directive_out( stdout, 0 );
 
 	skelout();
 
 	set_indent( 2 );
 
 	if ( yymore_used && ! yytext_is_array )
 		{
 		indent_puts( "yy_more_len = 0;" );
 		indent_puts( "if ( yy_more_flag )" );
 		indent_up();
 		indent_puts( "{" );
 		indent_puts( "yy_more_len = yy_c_buf_p - yytext_ptr;" );
 		indent_puts( "yy_more_flag = 0;" );
 		indent_puts( "}" );
 		indent_down();
 		}
 
 	skelout();
 
 	gen_start_state();
 
 	/* Note, don't use any indentation. */
 	outn( "yy_match:" );
 	gen_next_match();
 
 	skelout();
 	set_indent( 2 );
 	gen_find_action();
 
 	skelout();
 	if ( do_yylineno )
 		{
 		indent_puts( "if ( yy_act != YY_END_OF_BUFFER )" );
 		indent_up();
 		indent_puts( "{" );
 		indent_puts( "int yyl;" );
 		indent_puts( "for ( yyl = 0; yyl < yyleng; ++yyl )" );
 		indent_up();
 		indent_puts( "if ( yytext[yyl] == '\\n' )" );
 		indent_up();
 		indent_puts( "++yylineno;" );
 		indent_down();
 		indent_down();
 		indent_puts( "}" );
 		indent_down();
 		}
 
 	skelout();
 	if ( ddebug )
 		{
 		indent_puts( "if ( yy_flex_debug )" );
 		indent_up();
 
 		indent_puts( "{" );
 		indent_puts( "if ( yy_act == 0 )" );
 		indent_up();
 		indent_puts( C_plus_plus ?
 			"std::cerr << \"--scanner backing up\\n\";" :
 			"fprintf( stderr, \"--scanner backing up\\n\" );" );
 		indent_down();
 
 		do_indent();
 		out_dec( "else if ( yy_act < %d )\n", num_rules );
 		indent_up();
 
 		if ( C_plus_plus )
 			{
 			indent_puts(
 	"std::cerr << \"--accepting rule at line \" << yy_rule_linenum[yy_act] <<" );
 			indent_puts(
 			"         \"(\\\"\" << yytext << \"\\\")\\n\";" );
 			}
 		else
 			{
 			indent_puts(
 	"fprintf( stderr, \"--accepting rule at line %d (\\\"%s\\\")\\n\"," );
 
 			indent_puts(
 				"         yy_rule_linenum[yy_act], yytext );" );
 			}
 
 		indent_down();
 
 		do_indent();
 		out_dec( "else if ( yy_act == %d )\n", num_rules );
 		indent_up();
 
 		if ( C_plus_plus )
 			{
 			indent_puts(
 "std::cerr << \"--accepting default rule (\\\"\" << yytext << \"\\\")\\n\";" );
 			}
 		else
 			{
 			indent_puts(
 	"fprintf( stderr, \"--accepting default rule (\\\"%s\\\")\\n\"," );
 			indent_puts( "         yytext );" );
 			}
 
 		indent_down();
 
 		do_indent();
 		out_dec( "else if ( yy_act == %d )\n", num_rules + 1 );
 		indent_up();
 
 		indent_puts( C_plus_plus ?
 			"std::cerr << \"--(end of buffer or a NUL)\\n\";" :
 		"fprintf( stderr, \"--(end of buffer or a NUL)\\n\" );" );
 
 		indent_down();
 
 		do_indent();
 		outn( "else" );
 		indent_up();
 
 		if ( C_plus_plus )
 			{
 			indent_puts(
 	"std::cerr << \"--EOF (start condition \" << YY_START << \")\\n\";" );
 			}
 		else
 			{
 			indent_puts(
 	"fprintf( stderr, \"--EOF (start condition %d)\\n\", YY_START );" );
 			}
 
 		indent_down();
 
 		indent_puts( "}" );
 		indent_down();
 		}
 
 	/* Copy actions to output file. */
 	skelout();
 	indent_up();
 	gen_bu_action();
 	out( &action_array[action_offset] );
 
 	line_directive_out( stdout, 0 );
 
 	/* generate cases for any missing EOF rules */
 	for ( i = 1; i <= lastsc; ++i )
 		if ( ! sceof[i] )
 			{
 			do_indent();
 			out_str( "case YY_STATE_EOF(%s):\n", scname[i] );
 			did_eof_rule = true;
 			}
 
 	if ( did_eof_rule )
 		{
 		indent_up();
 		indent_puts( "yyterminate();" );
 		indent_down();
 		}
 
 
 	/* Generate code for handling NUL's, if needed. */
 
 	/* First, deal with backing up and setting up yy_cp if the scanner
 	 * finds that it should JAM on the NUL.
 	 */
 	skelout();
 	set_indent( 4 );
 
 	if ( fullspd || fulltbl )
 		indent_puts( "yy_cp = yy_c_buf_p;" );
 
 	else
 		{ /* compressed table */
 		if ( ! reject && ! interactive )
 			{
 			/* Do the guaranteed-needed backing up to figure
 			 * out the match.
 			 */
 			indent_puts( "yy_cp = yy_last_accepting_cpos;" );
 			indent_puts(
 				"yy_current_state = yy_last_accepting_state;" );
 			}
 
 		else
 			/* Still need to initialize yy_cp, though
 			 * yy_current_state was set up by
 			 * yy_get_previous_state().
 			 */
 			indent_puts( "yy_cp = yy_c_buf_p;" );
 		}
 
 
 	/* Generate code for yy_get_previous_state(). */
 	set_indent( 1 );
 	skelout();
 
 	gen_start_state();
 
 	set_indent( 2 );
 	skelout();
 	gen_next_state( true );
 
 	set_indent( 1 );
 	skelout();
 	gen_NUL_trans();
 
 	skelout();
 	if ( do_yylineno )
 		{ /* update yylineno inside of unput() */
 		indent_puts( "if ( c == '\\n' )" );
 		indent_up();
 		indent_puts( "--yylineno;" );
 		indent_down();
 		}
 
 	skelout();
 	/* Update BOL and yylineno inside of input(). */
 	if ( bol_needed )
 		{
 		indent_puts( "yy_current_buffer->yy_at_bol = (c == '\\n');" );
 		if ( do_yylineno )
 			{
 			indent_puts( "if ( yy_current_buffer->yy_at_bol )" );
 			indent_up();
 			indent_puts( "++yylineno;" );
 			indent_down();
 			}
 		}
 
 	else if ( do_yylineno )
 		{
 		indent_puts( "if ( c == '\\n' )" );
 		indent_up();
 		indent_puts( "++yylineno;" );
 		indent_down();
 		}
 
 	skelout();
 
 	/* Copy remainder of input to output. */
 
 	line_directive_out( stdout, 1 );
 
 	if ( sectnum == 3 )
 		(void) flexscan(); /* copy remainder of input to output */
 	}