curses.c

BeginningLinuxProgramming example6

    if (len > 0 && string[len - 1] == '\n')
	string[len - 1] = '\0';
}

/*
   add_record

   Add a new CD to the collection
 */

void add_record()
{
    char catalog_number[MAX_STRING];
    char cd_title[MAX_STRING];
    char cd_type[MAX_STRING];
    char cd_artist[MAX_STRING];
    char cd_entry[MAX_STRING];

    int screenrow = MESSAGE_LINE;
    int screencol = 10;

    clear_all_screen();
    mvprintw(screenrow, screencol, "Enter new CD details");
    screenrow += 2;

    mvprintw(screenrow, screencol, "Catalog Number: ");
    get_string(catalog_number);
    screenrow++;

    mvprintw(screenrow, screencol, "      CD Title: ");
    get_string(cd_title);
    screenrow++;

    mvprintw(screenrow, screencol, "       CD Type: ");
    get_string(cd_type);
    screenrow++;

    mvprintw(screenrow, screencol, "        Artist: ");
    get_string(cd_artist);
    screenrow++;

    mvprintw(15, 5, "About to add this new entry:");
    sprintf(cd_entry, "%s,%s,%s,%s", catalog_number, cd_title, cd_type, cd_artist);
    mvprintw(17, 5, "%s", cd_entry);
    refresh();

    move(PROMPT_LINE, 0);
    if (get_confirm()) {
	insert_title(cd_entry);
	strcpy(current_cd, cd_title);
	strcpy(current_cat, catalog_number);
    }
}

/*
   count_cds - scan the database and count titles and tracks
 */
void count_cds()
{
    FILE *titles_fp, *tracks_fp;
    char entry[MAX_ENTRY];
    int titles = 0;
    int tracks = 0;

    titles_fp = fopen(title_file, "r");
    if (titles_fp) {
	while (fgets(entry, MAX_ENTRY, titles_fp))
	    titles++;
	fclose(titles_fp);
    }
    tracks_fp = fopen(tracks_file, "r");
    if (tracks_fp) {
	while (fgets(entry, MAX_ENTRY, tracks_fp))
	    tracks++;
	fclose(tracks_fp);
    }
    mvprintw(ERROR_LINE, 0, "Database contains %d titles, with a total of %d tracks.", titles, tracks);
    get_return();
}

/*
   find_cd - locate a CD in the database

   prompt for a substring to match in the database
   set current_cd to the CD title

 */
void find_cd()
{
    char match[MAX_STRING], entry[MAX_ENTRY];
    FILE *titles_fp;
    int count = 0;
    char *found, *title, *catalog;

    mvprintw(Q_LINE, 0, "Enter a string to search for in CD titles: ");
    get_string(match);

    titles_fp = fopen(title_file, "r");
    if (titles_fp) {
	while (fgets(entry, MAX_ENTRY, titles_fp)) {

	    /* Skip past catalog number */
	    catalog = entry;
	    if (found = strstr(catalog, ",")) {
		*found = 0;
		title = found + 1;

		/* Zap the next comma in the entry to reduce it to title only */
		if (found = strstr(title, ",")) {
		    *found = '\0';

		    /* Now see if the match substring is present */
		    if (found = strstr(title, match)) {
			count++;
			strcpy(current_cd, title);
			strcpy(current_cat, catalog);
		    }
		}
	    }
	}
	fclose(titles_fp);
    }
    if (count != 1) {
	if (count == 0)
	    mvprintw(ERROR_LINE, 0, "Sorry, no matching CD found. ");
	if (count > 1)
	    mvprintw(ERROR_LINE, 0, "Sorry, match is ambiguous: %d CDs found. ", count);
	current_cd[0] = '\0';
	get_return();
    }
}


/*
   remove_tracks - delete tracks from the current CD
 */
void remove_tracks()
{
    FILE *tracks_fp, *temp_fp;
    char entry[MAX_ENTRY];
    int cat_length;

    if (current_cd[0] == '\0')
	return;

    cat_length = strlen(current_cat);

    tracks_fp = fopen(tracks_file, "r");
    temp_fp = fopen(temp_file, "w");

    while (fgets(entry, MAX_ENTRY, tracks_fp)) {
	/* Compare catalog number and copy entry if no match */
	if (strncmp(current_cat, entry, cat_length) != 0)
	    fputs(entry, temp_fp);
    }
    fclose(tracks_fp);
    fclose(temp_fp);

    unlink(tracks_file);
    rename(temp_file, tracks_file);
}

/*
   remove_cd - delete the current CD from the database
 */
void remove_cd()
{
    FILE *titles_fp, *temp_fp;
    char entry[MAX_ENTRY];
    int cat_length;

    if (current_cd[0] == '\0')
	return;

    clear_all_screen();
    mvprintw(PROMPT_LINE, 0, "About to remove CD %s: %s. ", current_cat, current_cd);
    if (!get_confirm())
	return;

    cat_length = strlen(current_cat);

    /* Copy the titles file to a temporary, ignoring this CD */
    titles_fp = fopen(title_file, "r");
    temp_fp = fopen(temp_file, "w");

    while (fgets(entry, MAX_ENTRY, titles_fp)) {
	/* Compare catalog number and copy entry if no match */
	if (strncmp(current_cat, entry, cat_length) != 0)
	    fputs(entry, temp_fp);
    }
    fclose(titles_fp);
    fclose(temp_fp);

    /* Delete the titles file, and rename the temporary file */
    unlink(title_file);
    rename(temp_file, title_file);

    /* Now do the same for the tracks file */
    remove_tracks();

    /* Reset current CD to 'None' */
    current_cd[0] = '\0';
}


/*
   Some defines we use only for showing or entering the track information
 */
#define BOXED_LINES    11
#define BOXED_ROWS     60
#define BOX_LINE_POS   8
#define BOX_ROW_POS    2
/*
   list_tracks - list the tracks for the current CD
 */
void list_tracks()
{
    FILE *tracks_fp;
    char entry[MAX_ENTRY];
    int cat_length;
    int lines_op = 0;
    WINDOW *track_pad_ptr;
    int tracks = 0;
    int key;
    int first_line = 0;

    if (current_cd[0] == '\0') {
	mvprintw(ERROR_LINE, 0, "You must select a CD first. ", stdout);
	get_return();
	return;
    }
    clear_all_screen();
    cat_length = strlen(current_cat);

    /* First count the number of tracks for the current CD */
    tracks_fp = fopen(tracks_file, "r");
    if (!tracks_fp)
	return;
    while (fgets(entry, MAX_ENTRY, tracks_fp)) {
	if (strncmp(current_cat, entry, cat_length) == 0)
	    tracks++;
    }
    fclose(tracks_fp);


    /* Make a new pad, ensure that even if there is only a single
       track the PAD is large enough so the later prefresh() is always
       valid.
     */
    track_pad_ptr = newpad(tracks + 1 + BOXED_LINES, BOXED_ROWS + 1);
    if (!track_pad_ptr)
	return;

    tracks_fp = fopen(tracks_file, "r");
    if (!tracks_fp)
	return;

    mvprintw(4, 0, "CD Track Listing\n");

    /* write the track information into the pad */
    while (fgets(entry, MAX_ENTRY, tracks_fp)) {
	/* Compare catalog number and output rest of entry */
	if (strncmp(current_cat, entry, cat_length) == 0) {
	    mvwprintw(track_pad_ptr, lines_op++, 0, "%s", entry + cat_length + 1);
	}
    }
    fclose(tracks_fp);

    if (lines_op > BOXED_LINES) {
	mvprintw(MESSAGE_LINE, 0, "Cursor keys to scroll, RETURN or q to exit");
    } else {
	mvprintw(MESSAGE_LINE, 0, "RETURN or q to exit");
    }
    wrefresh(stdscr);
    keypad(stdscr, TRUE);
    cbreak();
    noecho();

    key = 0;
    while (key != 'q' && key != KEY_ENTER && key != '\n') {
	if (key == KEY_UP) {
	    if (first_line > 0)
		first_line--;
	}
	if (key == KEY_DOWN) {
	    if (first_line + BOXED_LINES + 1 < tracks)
		first_line++;
	}
	/* now draw the appropriate part of the pad on the screen */
	prefresh(track_pad_ptr, first_line, 0,
		 BOX_LINE_POS, BOX_ROW_POS,
		 BOX_LINE_POS + BOXED_LINES, BOX_ROW_POS + BOXED_ROWS);
/*	wrefresh(stdscr); */
	key = getch();
    }

    delwin(track_pad_ptr);
    keypad(stdscr, FALSE);
    nocbreak();
    echo();
}

/*
   update_cd - re-enter tracks for current CD

   deletes all tracks for the current CD in the database
   and then prompts for new ones.
 */
void update_cd()
{
    FILE *tracks_fp;
    char track_name[MAX_STRING];
    int len;
    int track = 1;
    int screen_line = 1;
    WINDOW *box_window_ptr;
    WINDOW *sub_window_ptr;

    clear_all_screen();
    mvprintw(PROMPT_LINE, 0, "Re-entering tracks for CD. ");
    if (!get_confirm())
	return;
    move(PROMPT_LINE, 0);
    clrtoeol();

    remove_tracks();

    mvprintw(MESSAGE_LINE, 0, "Enter a blank line to finish");

    tracks_fp = fopen(tracks_file, "a");

    /* Just to show how, enter the information in a scrolling, boxed,
       window. The trick is to set-up a sub-window, draw a box around the
       edge, then add a new, scrolling, sub-window just inside the boxed
       sub-window. */
    box_window_ptr = subwin(stdscr, BOXED_LINES + 2, BOXED_ROWS + 2,
			    BOX_LINE_POS - 1, BOX_ROW_POS - 1);
    if (!box_window_ptr)
	return;
    box(box_window_ptr, ACS_VLINE, ACS_HLINE);

    sub_window_ptr = subwin(stdscr, BOXED_LINES, BOXED_ROWS,
			    BOX_LINE_POS, BOX_ROW_POS);
    if (!sub_window_ptr)
	return;
    scrollok(sub_window_ptr, TRUE);
    werase(sub_window_ptr);
    touchwin(stdscr);

    do {

	mvwprintw(sub_window_ptr, screen_line++, BOX_ROW_POS + 2, "Track %d: ", track);
	clrtoeol();
	refresh();
	wgetnstr(sub_window_ptr, track_name, MAX_STRING);
	len = strlen(track_name);
	if (len > 0 && track_name[len - 1] == '\n')
	    track_name[len - 1] = '\0';

	if (*track_name)
	    fprintf(tracks_fp, "%s,%d,%s\n", current_cat, track, track_name);
	track++;
	if (screen_line > BOXED_LINES - 1) {
	    /* time to start scrolling */
	    scroll(sub_window_ptr);
	    screen_line--;
	}
    } while (*track_name);
    delwin(sub_window_ptr);

    fclose(tracks_fp);
}