gen.c

操作系统源代码

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

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

	dataend();
	}

    total_states = lastdfa + numtemps;

    printf( tblend > MAX_SHORT ? C_long_decl : C_short_decl,
	    "yy_base", 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 ? C_long_decl : C_short_decl,
	    "yy_def", total_states + 1 );

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

    dataend();

    printf( lastdfa > MAX_SHORT ? C_long_decl : C_short_decl,
	    "yy_nxt", 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 ? 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();
    }


/* 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();
    printf( fmt, arg );
    putchar( '\n' );
    }


/* write out a string at the current indentation level, adding a final
 * newline
 */

void indent_puts( str )
char str[];

    {
    do_indent();
    puts( str );
    }


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

void make_tables()

    {
    register int i;
    int did_eof_rule = false;

    skelout();

    /* first, take care of YY_DO_BEFORE_ACTION depending on yymore being used */
    set_indent( 2 );

    if ( yymore_used )
	{
	indent_puts( "yytext -= yy_more_len; \\" );
	indent_puts( "yyleng = yy_cp - yytext; \\" );
	}

    else
	indent_puts( "yyleng = yy_cp - yy_bp; \\" );

    set_indent( 0 );
    
    skelout();


    printf( "#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" : "short";

	set_indent( 0 );
	indent_puts( "struct yy_trans_info" );
	indent_up();
        indent_puts( "{" );
        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();

	indent_puts( "typedef const struct yy_trans_info *yy_state_type;" );
	}
    
    else
	indent_puts( "typedef int yy_state_type;" );

    if ( fullspd )
	genctbl();

    else if ( fulltbl )
	genftbl();

    else
	gentabs();

    if ( num_backtracking > 0 )
	{
	indent_puts( "static yy_state_type yy_last_accepting_state;" );
	indent_puts( "static YY_CHAR *yy_last_accepting_cpos;\n" );
	}

    if ( nultrans )
	{
	printf( C_state_decl, "yy_NUL_trans", lastdfa + 1 );

	for ( i = 1; i <= lastdfa; ++i )
	    {
	    if ( fullspd )
		{
		if ( nultrans )
		    printf( "    &yy_transition[%d],\n", base[i] );
		else
		    printf( "    0,\n" );
		}
	    
	    else
		mkdata( nultrans[i] );
	    }

	dataend();
	}

    if ( ddebug )
	{ /* spit out table mapping rules to line numbers */
	indent_puts( "extern int yy_flex_debug;" );
	indent_puts( "int yy_flex_debug = 1;\n" );

	printf( 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 */
	puts(
	"static yy_state_type yy_state_buf[YY_BUF_SIZE + 2], *yy_state_ptr;" );
	puts( "static YY_CHAR *yy_full_match;" );
	puts( "static int yy_lp;" );

	if ( variable_trailing_context_rules )
	    {
	    puts( "static int yy_looking_for_trail_begin = 0;" );
	    puts( "static int yy_full_lp;" );
	    puts( "static int *yy_full_state;" );
	    printf( "#define YY_TRAILING_MASK 0x%x\n", YY_TRAILING_MASK );
	    printf( "#define YY_TRAILING_HEAD_MASK 0x%x\n",
		    YY_TRAILING_HEAD_MASK );
	    }

	puts( "#define REJECT \\" );
        puts( "{ \\" );
        puts(
	"*yy_cp = yy_hold_char; /* undo effects of setting up yytext */ \\" );
        puts(
	    "yy_cp = yy_full_match; /* restore poss. backed-over text */ \\" );

	if ( variable_trailing_context_rules )
	    {
	    puts( "yy_lp = yy_full_lp; /* restore orig. accepting pos. */ \\" );
	    puts(
		"yy_state_ptr = yy_full_state; /* restore orig. state */ \\" );
	    puts(
	    "yy_current_state = *yy_state_ptr; /* restore curr. state */ \\" );
	    }

        puts( "++yy_lp; \\" );
        puts( "goto find_rule; \\" );
        puts( "}" );
	}
    
    else
	{
	puts( "/* the intent behind this definition is that it'll catch" );
	puts( " * any uses of REJECT which flex missed" );
	puts( " */" );
	puts( "#define REJECT reject_used_but_not_detected" );
	}
    
    if ( yymore_used )
	{
	indent_puts( "static int yy_more_flag = 0;" );
	indent_puts( "static int yy_doing_yy_more = 0;" );
	indent_puts( "static int yy_more_len = 0;" );
	indent_puts(
	    "#define yymore() { yy_more_flag = 1; }" );
	indent_puts(
	    "#define YY_MORE_ADJ (yy_doing_yy_more ? yy_more_len : 0)" );
	}

    else
	{
	indent_puts( "#define yymore() yymore_used_but_not_detected" );
	indent_puts( "#define YY_MORE_ADJ 0" );
	}

    skelout();

    if ( ferror( temp_action_file ) )
	flexfatal( "error occurred when writing temporary action file" );

    else if ( fclose( temp_action_file ) )
	flexfatal( "error occurred when closing temporary action file" );

    temp_action_file = fopen( action_file_name, "r" );

    if ( temp_action_file == NULL )
	flexfatal( "could not re-open temporary action file" );

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

    skelout();

    set_indent( 2 );

    if ( yymore_used )
	{
	indent_puts( "yy_more_len = 0;" );
	indent_puts( "yy_doing_yy_more = yy_more_flag;" );
	indent_puts( "if ( yy_doing_yy_more )" );
	indent_up();
	indent_puts( "{" );
	indent_puts( "yy_more_len = yyleng;" );
	indent_puts( "yy_more_flag = 0;" );
	indent_puts( "}" );
	indent_down();
	}

    skelout();

    gen_start_state();

    /* note, don't use any indentation */
    puts( "yy_match:" );
    gen_next_match();

    skelout();
    set_indent( 2 );
    gen_find_action();

    skelout();
    if ( ddebug )
	{
	indent_puts( "if ( yy_flex_debug )" );
	indent_up();

	indent_puts( "{" );
	indent_puts( "if ( yy_act == 0 )" );
	indent_up();
	indent_puts( "fprintf( stderr, \"--scanner backtracking\\n\" );" );
	indent_down();

	do_indent();
	printf( "else if ( yy_act < %d )\n", num_rules );
	indent_up();
	indent_puts(
	"fprintf( stderr, \"--accepting rule at line %d (\\\"%s\\\")\\n\"," );
	indent_puts( "         yy_rule_linenum[yy_act], yytext );" );
	indent_down();

	do_indent();
	printf( "else if ( yy_act == %d )\n", num_rules );
	indent_up();
	indent_puts(
	"fprintf( stderr, \"--accepting default rule (\\\"%s\\\")\\n\"," );
	indent_puts( "         yytext );" );
	indent_down();

	do_indent();
	printf( "else if ( yy_act == %d )\n", num_rules + 1 );
	indent_up();
	indent_puts( "fprintf( stderr, \"--(end of buffer or a NUL)\\n\" );" );
	indent_down();

	do_indent();
	printf( "else\n" );
	indent_up();
	indent_puts( "fprintf( stderr, \"--EOF\\n\" );" );
	indent_down();

	indent_puts( "}" );
	indent_down();
	}

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

    /* generate cases for any missing EOF rules */
    for ( i = 1; i <= lastsc; ++i )
	if ( ! sceof[i] )
	    {
	    do_indent();
	    printf( "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 backtracking and setting up yy_cp if the scanner
     * finds that it should JAM on the NUL
     */
    skelout();
    set_indent( 7 );

    if ( fullspd || fulltbl )
	indent_puts( "yy_cp = yy_c_buf_p;" );
    
    else
	{ /* compressed table */
	if ( ! reject && ! interactive )
	    {
	    /* do the guaranteed-needed backtrack to figure out the match */
	    indent_puts( "yy_cp = yy_last_accepting_cpos;" );
	    indent_puts( "yy_current_state = yy_last_accepting_state;" );
	    }
	}


    /* generate code for yy_get_previous_state() */
    set_indent( 1 );
    skelout();

    if ( bol_needed )
	indent_puts( "register YY_CHAR *yy_bp = yytext;\n" );

    gen_start_state();

    set_indent( 2 );
    skelout();
    gen_next_state( true );

    set_indent( 1 );
    skelout();
    gen_NUL_trans();

    skelout();

    /* copy remainder of input to output */

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