textbox.c

busybox-1.2.0的源码包

	    wmove (dialog, cur_y, cur_x);
	    wrefresh (dialog);
	    break;
	case '0':		/* Beginning of line */
	case 'H':		/* Scroll left */
	case 'h':
	case KEY_LEFT:
	    if (hscroll <= 0)
		break;

	    if (key == '0')
		hscroll = 0;
	    else
		hscroll--;
	    /* Reprint current page to scroll horizontally */
	    back_lines (page_length);
	    print_page (text, height - 4, width - 2);
	    wmove (dialog, cur_y, cur_x);
	    wrefresh (dialog);
	    break;
	case 'L':		/* Scroll right */
	case 'l':
	case KEY_RIGHT:
	    if (hscroll >= MAX_LEN)
		break;
	    hscroll++;
	    /* Reprint current page to scroll horizontally */
	    back_lines (page_length);
	    print_page (text, height - 4, width - 2);
	    wmove (dialog, cur_y, cur_x);
	    wrefresh (dialog);
	    break;
	case ESC:
	    break;
	}
    }

    delwin (dialog);
    free (buf);
    close (fd);
    return 1;			/* ESC pressed */
}

/*
 * Go back 'n' lines in text file. Called by dialog_textbox().
 * 'page' will be updated to point to the desired line in 'buf'.
 */
static void
back_lines (int n)
{
    int i, fpos;

    begin_reached = 0;
    /* We have to distinguish between end_reached and !end_reached
       since at end of file, the line is not ended by a '\n'.
       The code inside 'if' basically does a '--page' to move one
       character backward so as to skip '\n' of the previous line */
    if (!end_reached) {
	/* Either beginning of buffer or beginning of file reached? */
	if (page == buf) {
	    if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
		endwin ();
		fprintf (stderr, "\nError moving file pointer in "
			 "back_lines().\n");
		exit (-1);
	    }
	    if (fpos > bytes_read) {	/* Not beginning of file yet */
		/* We've reached beginning of buffer, but not beginning of
		   file yet, so read previous part of file into buffer.
		   Note that we only move backward for BUF_SIZE/2 bytes,
		   but not BUF_SIZE bytes to avoid re-reading again in
		   print_page() later */
		/* Really possible to move backward BUF_SIZE/2 bytes? */
		if (fpos < BUF_SIZE / 2 + bytes_read) {
		    /* No, move less then */
		    if (lseek (fd, 0, SEEK_SET) == -1) {
			endwin ();
			fprintf (stderr, "\nError moving file pointer in "
				 "back_lines().\n");
			exit (-1);
		    }
		    page = buf + fpos - bytes_read;
		} else {	/* Move backward BUF_SIZE/2 bytes */
		    if (lseek (fd, -(BUF_SIZE / 2 + bytes_read), SEEK_CUR)
			== -1) {
			endwin ();
			fprintf (stderr, "\nError moving file pointer "
				 "in back_lines().\n");
			exit (-1);
		    }
		    page = buf + BUF_SIZE / 2;
		}
		if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
		    endwin ();
		    fprintf (stderr, "\nError reading file in back_lines().\n");
		    exit (-1);
		}
		buf[bytes_read] = '\0';
	    } else {		/* Beginning of file reached */
		begin_reached = 1;
		return;
	    }
	}
	if (*(--page) != '\n') {	/* '--page' here */
	    /* Something's wrong... */
	    endwin ();
	    fprintf (stderr, "\nInternal error in back_lines().\n");
	    exit (-1);
	}
    }
    /* Go back 'n' lines */
    for (i = 0; i < n; i++)
	do {
	    if (page == buf) {
		if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
		    endwin ();
		    fprintf (stderr,
			  "\nError moving file pointer in back_lines().\n");
		    exit (-1);
		}
		if (fpos > bytes_read) {
		    /* Really possible to move backward BUF_SIZE/2 bytes? */
		    if (fpos < BUF_SIZE / 2 + bytes_read) {
			/* No, move less then */
			if (lseek (fd, 0, SEEK_SET) == -1) {
			    endwin ();
			    fprintf (stderr, "\nError moving file pointer "
				     "in back_lines().\n");
			    exit (-1);
			}
			page = buf + fpos - bytes_read;
		    } else {	/* Move backward BUF_SIZE/2 bytes */
			if (lseek (fd, -(BUF_SIZE / 2 + bytes_read),
				   SEEK_CUR) == -1) {
			    endwin ();
			    fprintf (stderr, "\nError moving file pointer"
				     " in back_lines().\n");
			    exit (-1);
			}
			page = buf + BUF_SIZE / 2;
		    }
		    if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
			endwin ();
			fprintf (stderr, "\nError reading file in "
				 "back_lines().\n");
			exit (-1);
		    }
		    buf[bytes_read] = '\0';
		} else {	/* Beginning of file reached */
		    begin_reached = 1;
		    return;
		}
	    }
	} while (*(--page) != '\n');
    page++;
}

/*
 * Print a new page of text. Called by dialog_textbox().
 */
static void
print_page (WINDOW * win, int height, int width)
{
    int i, passed_end = 0;

    page_length = 0;
    for (i = 0; i < height; i++) {
	print_line (win, i, width);
	if (!passed_end)
	    page_length++;
	if (end_reached && !passed_end)
	    passed_end = 1;
    }
    wnoutrefresh (win);
}

/*
 * Print a new line of text. Called by dialog_textbox() and print_page().
 */
static void
print_line (WINDOW * win, int row, int width)
{
    int y, x;
    char *line;

    line = get_line ();
    line += MIN (strlen (line), hscroll);	/* Scroll horizontally */
    wmove (win, row, 0);	/* move cursor to correct line */
    waddch (win, ' ');
    waddnstr (win, line, MIN (strlen (line), width - 2));

    getyx (win, y, x);
    /* Clear 'residue' of previous line */
#if OLD_NCURSES
    {
	int i;
	for (i = 0; i < width - x; i++)
	    waddch (win, ' ');
    }
#else
    wclrtoeol(win);
#endif
}

/*
 * Return current line of text. Called by dialog_textbox() and print_line().
 * 'page' should point to start of current line before calling, and will be
 * updated to point to start of next line.
 */
static char *
get_line (void)
{
    int i = 0, fpos;
    static char line[MAX_LEN + 1];

    end_reached = 0;
    while (*page != '\n') {
	if (*page == '\0') {
	    /* Either end of file or end of buffer reached */
	    if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
		endwin ();
		fprintf (stderr, "\nError moving file pointer in "
			 "get_line().\n");
		exit (-1);
	    }
	    if (fpos < file_size) {	/* Not end of file yet */
		/* We've reached end of buffer, but not end of file yet,
		   so read next part of file into buffer */
		if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
		    endwin ();
		    fprintf (stderr, "\nError reading file in get_line().\n");
		    exit (-1);
		}
		buf[bytes_read] = '\0';
		page = buf;
	    } else {
		if (!end_reached)
		    end_reached = 1;
		break;
	    }
	} else if (i < MAX_LEN)
	    line[i++] = *(page++);
	else {
	    /* Truncate lines longer than MAX_LEN characters */
	    if (i == MAX_LEN)
		line[i++] = '\0';
	    page++;
	}
    }
    if (i <= MAX_LEN)
	line[i] = '\0';
    if (!end_reached)
	page++;			/* move pass '\n' */

    return line;
}

/*
 * Print current position
 */
static void
print_position (WINDOW * win, int height, int width)
{
    int fpos, percent;

    if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
	endwin ();
	fprintf (stderr, "\nError moving file pointer in print_position().\n");
	exit (-1);
    }
    wattrset (win, position_indicator_attr);
    wbkgdset (win, position_indicator_attr & A_COLOR);
    percent = !file_size ?
	100 : ((fpos - bytes_read + page - buf) * 100) / file_size;
    wmove (win, height - 3, width - 9);
    wprintw (win, "(%3d%%)", percent);
}