initscan.c

操作系统源代码

		 * of the first EOB in the buffer, since yy_c_buf_p will
		 * already have been incremented past the NUL character
		 * (since all states make transitions on EOB to the end-
		 * of-buffer state).  Contrast this with the test in yyinput().
		 */
		if ( yy_c_buf_p <= &yy_current_buffer->yy_ch_buf[yy_n_chars] )
		    /* this was really a NUL */
		    {
		    yy_state_type yy_next_state;

		    yy_c_buf_p = yytext + yy_amount_of_matched_text;

		    yy_current_state = yy_get_previous_state();

		    /* okay, we're now positioned to make the
		     * NUL transition.  We couldn't have
		     * yy_get_previous_state() go ahead and do it
		     * for us because it doesn't know how to deal
		     * with the possibility of jamming (and we
		     * don't want to build jamming into it because
		     * then it will run more slowly)
		     */

		    yy_next_state = yy_try_NUL_trans( yy_current_state );

		    yy_bp = yytext + YY_MORE_ADJ;

		    if ( yy_next_state )
			{
			/* consume the NUL */
			yy_cp = ++yy_c_buf_p;
			yy_current_state = yy_next_state;
			goto yy_match;
			}

		    else
			{
			    yy_cp = yy_last_accepting_cpos;
			    yy_current_state = yy_last_accepting_state;
			goto yy_find_action;
			}
		    }

		else switch ( yy_get_next_buffer() )
		    {
		    case EOB_ACT_END_OF_FILE:
			{
			yy_did_buffer_switch_on_eof = 0;

			if ( yywrap() )
			    {
			    /* note: because we've taken care in
			     * yy_get_next_buffer() to have set up yytext,
			     * we can now set up yy_c_buf_p so that if some
			     * total hoser (like flex itself) wants
			     * to call the scanner after we return the
			     * YY_NULL, it'll still work - another YY_NULL
			     * will get returned.
			     */
			    yy_c_buf_p = yytext + YY_MORE_ADJ;

			    yy_act = YY_STATE_EOF((yy_start - 1) / 2);
			    goto do_action;
			    }

			else
			    {
			    if ( ! yy_did_buffer_switch_on_eof )
				YY_NEW_FILE;
			    }
			}
			break;

		    case EOB_ACT_CONTINUE_SCAN:
			yy_c_buf_p = yytext + yy_amount_of_matched_text;

			yy_current_state = yy_get_previous_state();

			yy_cp = yy_c_buf_p;
			yy_bp = yytext + YY_MORE_ADJ;
			goto yy_match;

		    case EOB_ACT_LAST_MATCH:
			yy_c_buf_p =
			    &yy_current_buffer->yy_ch_buf[yy_n_chars];

			yy_current_state = yy_get_previous_state();

			yy_cp = yy_c_buf_p;
			yy_bp = yytext + YY_MORE_ADJ;
			goto yy_find_action;
		    }
		break;
		}

	    default:
#ifdef FLEX_DEBUG
		printf( "action # %d\n", yy_act );
#endif
		YY_FATAL_ERROR(
			"fatal flex scanner internal error--no action found" );
	    }
	}
    }


/* yy_get_next_buffer - try to read in a new buffer
 *
 * synopsis
 *     int yy_get_next_buffer();
 *     
 * returns a code representing an action
 *     EOB_ACT_LAST_MATCH - 
 *     EOB_ACT_CONTINUE_SCAN - continue scanning from current position
 *     EOB_ACT_END_OF_FILE - end of file
 */

static int yy_get_next_buffer()

    {
    register YY_CHAR *dest = yy_current_buffer->yy_ch_buf;
    register YY_CHAR *source = yytext - 1; /* copy prev. char, too */
    register int number_to_move, i;
    int ret_val;

    if ( yy_c_buf_p > &yy_current_buffer->yy_ch_buf[yy_n_chars + 1] )
	YY_FATAL_ERROR(
		"fatal flex scanner internal error--end of buffer missed" );

    /* try to read more data */

    /* first move last chars to start of buffer */
    number_to_move = yy_c_buf_p - yytext;

    for ( i = 0; i < number_to_move; ++i )
	*(dest++) = *(source++);

    if ( yy_current_buffer->yy_eof_status != EOF_NOT_SEEN )
	/* don't do the read, it's not guaranteed to return an EOF,
	 * just force an EOF
	 */
	yy_n_chars = 0;

    else
	{
	int num_to_read = yy_current_buffer->yy_buf_size - number_to_move - 1;

	if ( num_to_read > YY_READ_BUF_SIZE )
	    num_to_read = YY_READ_BUF_SIZE;

	else if ( num_to_read <= 0 )
	    YY_FATAL_ERROR( "fatal error - scanner input buffer overflow" );

	/* read in more data */
	YY_INPUT( (&yy_current_buffer->yy_ch_buf[number_to_move]),
		  yy_n_chars, num_to_read );
	}

    if ( yy_n_chars == 0 )
	{
	if ( number_to_move == 1 )
	    {
	    ret_val = EOB_ACT_END_OF_FILE;
	    yy_current_buffer->yy_eof_status = EOF_DONE;
	    }

	else
	    {
	    ret_val = EOB_ACT_LAST_MATCH;
	    yy_current_buffer->yy_eof_status = EOF_PENDING;
	    }
	}

    else
	ret_val = EOB_ACT_CONTINUE_SCAN;

    yy_n_chars += number_to_move;
    yy_current_buffer->yy_ch_buf[yy_n_chars] = YY_END_OF_BUFFER_CHAR;
    yy_current_buffer->yy_ch_buf[yy_n_chars + 1] = YY_END_OF_BUFFER_CHAR;

    /* yytext begins at the second character in yy_ch_buf; the first
     * character is the one which preceded it before reading in the latest
     * buffer; it needs to be kept around in case it's a newline, so
     * yy_get_previous_state() will have with '^' rules active
     */

    yytext = &yy_current_buffer->yy_ch_buf[1];

    return ( ret_val );
    }


/* yy_get_previous_state - get the state just before the EOB char was reached
 *
 * synopsis
 *     yy_state_type yy_get_previous_state();
 */

static yy_state_type yy_get_previous_state()

    {
    register yy_state_type yy_current_state;
    register YY_CHAR *yy_cp;

    register YY_CHAR *yy_bp = yytext;

    yy_current_state = yy_start;
    if ( yy_bp[-1] == '\n' )
	++yy_current_state;

    for ( yy_cp = yytext + YY_MORE_ADJ; yy_cp < yy_c_buf_p; ++yy_cp )
	{
	register YY_CHAR yy_c = (*yy_cp ? yy_ec[*yy_cp] : 1);
	if ( yy_accept[yy_current_state] )
	    {
	    yy_last_accepting_state = yy_current_state;
	    yy_last_accepting_cpos = yy_cp;
	    }
	while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
	    {
	    yy_current_state = yy_def[yy_current_state];
	    if ( yy_current_state >= 341 )
		yy_c = yy_meta[yy_c];
	    }
	yy_current_state = yy_nxt[yy_base[yy_current_state] + yy_c];
	}

    return ( yy_current_state );
    }


/* yy_try_NUL_trans - try to make a transition on the NUL character
 *
 * synopsis
 *     next_state = yy_try_NUL_trans( current_state );
 */

#ifdef YY_USE_PROTOS
static yy_state_type yy_try_NUL_trans( register yy_state_type yy_current_state )
#else
static yy_state_type yy_try_NUL_trans( yy_current_state )
register yy_state_type yy_current_state;
#endif

    {
    register int yy_is_jam;
    register YY_CHAR *yy_cp = yy_c_buf_p;

    register YY_CHAR yy_c = 1;
    if ( yy_accept[yy_current_state] )
	{
	yy_last_accepting_state = yy_current_state;
	yy_last_accepting_cpos = yy_cp;
	}
    while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
	{
	yy_current_state = yy_def[yy_current_state];
	if ( yy_current_state >= 341 )
	    yy_c = yy_meta[yy_c];
	}
    yy_current_state = yy_nxt[yy_base[yy_current_state] + yy_c];
    yy_is_jam = (yy_current_state == 340);

    return ( yy_is_jam ? 0 : yy_current_state );
    }


#ifdef YY_USE_PROTOS
static void yyunput( YY_CHAR c, register YY_CHAR *yy_bp )
#else
static void yyunput( c, yy_bp )
YY_CHAR c;
register YY_CHAR *yy_bp;
#endif

    {
    register YY_CHAR *yy_cp = yy_c_buf_p;

    /* undo effects of setting up yytext */
    *yy_cp = yy_hold_char;

    if ( yy_cp < yy_current_buffer->yy_ch_buf + 2 )
	{ /* need to shift things up to make room */
	register int number_to_move = yy_n_chars + 2; /* +2 for EOB chars */
	register YY_CHAR *dest =
	    &yy_current_buffer->yy_ch_buf[yy_current_buffer->yy_buf_size + 2];
	register YY_CHAR *source =
	    &yy_current_buffer->yy_ch_buf[number_to_move];

	while ( source > yy_current_buffer->yy_ch_buf )
	    *--dest = *--source;

	yy_cp += dest - source;
	yy_bp += dest - source;
	yy_n_chars = yy_current_buffer->yy_buf_size;

	if ( yy_cp < yy_current_buffer->yy_ch_buf + 2 )
	    YY_FATAL_ERROR( "flex scanner push-back overflow" );
	}

    if ( yy_cp > yy_bp && yy_cp[-1] == '\n' )
	yy_cp[-2] = '\n';

    *--yy_cp = c;

    /* note: the formal parameter *must* be called "yy_bp" for this
     *       macro to now work correctly
     */
    YY_DO_BEFORE_ACTION; /* set up yytext again */
    }


#ifdef __cplusplus
static int yyinput()
#else
static int input()
#endif

    {
    int c;
    YY_CHAR *yy_cp = yy_c_buf_p;

    *yy_cp = yy_hold_char;

    if ( *yy_c_buf_p == YY_END_OF_BUFFER_CHAR )
	{
	/* yy_c_buf_p now points to the character we want to return.
	 * If this occurs *before* the EOB characters, then it's a
	 * valid NUL; if not, then we've hit the end of the buffer.
	 */
	if ( yy_c_buf_p < &yy_current_buffer->yy_ch_buf[yy_n_chars] )
	    /* this was really a NUL */
	    *yy_c_buf_p = '\0';

	else
	    { /* need more input */
	    yytext = yy_c_buf_p;
	    ++yy_c_buf_p;

	    switch ( yy_get_next_buffer() )
		{
		case EOB_ACT_END_OF_FILE:
		    {
		    if ( yywrap() )
			{
			yy_c_buf_p = yytext + YY_MORE_ADJ;
			return ( EOF );
			}

		    YY_NEW_FILE;

#ifdef __cplusplus
		    return ( yyinput() );
#else
		    return ( input() );
#endif
		    }
		    break;

		case EOB_ACT_CONTINUE_SCAN:
		    yy_c_buf_p = yytext + YY_MORE_ADJ;
		    break;

		case EOB_ACT_LAST_MATCH:
#ifdef __cplusplus
		    YY_FATAL_ERROR( "unexpected last match in yyinput()" );
#else
		    YY_FATAL_ERROR( "unexpected last match in input()" );
#endif
		}
	    }
	}

    c = *yy_c_buf_p;
    yy_hold_char = *++yy_c_buf_p;

    return ( c );
    }


#ifdef YY_USE_PROTOS
void yyrestart( FILE *input_file )
#else
void yyrestart( input_file )
FILE *input_file;
#endif

    {
    yy_init_buffer( yy_current_buffer, input_file );
    yy_load_buffer_state();
    }


#ifdef YY_USE_PROTOS
void yy_switch_to_buffer( YY_BUFFER_STATE new_buffer )
#else
void yy_switch_to_buffer( new_buffer )
YY_BUFFER_STATE new_buffer;
#endif

    {
    if ( yy_current_buffer == new_buffer )
	return;

    if ( yy_current_buffer )
	{
	/* flush out information for old buffer */
	*yy_c_buf_p = yy_hold_char;
	yy_current_buffer->yy_buf_pos = yy_c_buf_p;
	yy_current_buffer->yy_n_chars = yy_n_chars;
	}

    yy_current_buffer = new_buffer;
    yy_load_buffer_state();

    /* we don't actually know whether we did this switch during
     * EOF (yywrap()) processing, but the only time this flag
     * is looked at is after yywrap() is called, so it's safe
     * to go ahead and always set it.
     */
    yy_did_buffer_switch_on_eof = 1;
    }


#ifdef YY_USE_PROTOS
void yy_load_buffer_state( void )
#else
void yy_load_buffer_state()
#endif

    {
    yy_n_chars = yy_current_buffer->yy_n_chars;
    yytext = yy_c_buf_p = yy_current_buffer->yy_buf_pos;
    yyin = yy_current_buffer->yy_input_file;
    yy_hold_char = *y