/*******************************************************************************

一个管理CD唱片的程序。[《linux程序设计第4版》6.10节例程]

使用菜单完成“增、删、改、查”四项功能，使用文本存储数据。

TITLE_FILE 存储标题信息 ： 目录编号,标题,曲目类型,艺术家

TRACKS_FILE 存储曲目信息： 目录编号,曲目编号,曲名

目录编号因为是惟一的，所以用来关联2个文件，标题文件的一个数据项一般会对应曲目文件的多行数据。

“增”操作：仅指向标题文件中增加一条CD记录。而CD的曲目信息，通过“改”操作录入。

fopen(), wgetnstr(), fprintf(), fclose().

“查”操作：引导用户输入需要查找的标题，逐行读取标题文件，进行匹配。

wgetnstr()（curses库函数）, fopen(), fgets(), strstr() or strcmp(), fclose().

不会把所有CD以列表形式呈现，所以针对某张CD操作时，必须先“查”，目前版本仅支持“标题”查找。

需要变量 current_cd 存储“当前CD标题”，“增、查”2个操作会更新该变量，“删”重置该变量为'\0'。

“删”操作：删除当前CD记录，及其所有曲目。

曲目文件每个条目，也就是每行的开头是目录编号；

查找曲目文件中与“当前目录编号”不匹配的行，并写入临时文件，

而匹配的行被丢弃，以达到删除的目的。

fopen(), fgets(), strncmp(), fputs(), fclose().

“改”操作：不支持针对某个曲目编号的修改，需要先删除某个目录编号的所有曲目，然后重新录入。

与“删api、增api”相同。

by li2, 2014-07-22~23, ShangHai ZhaBei.

********************************************************************************

使用到的API

FILE *fopen(const char *filename, const char *mode); 打开指定的文件，并关联到文件流。

FILE *fclose(FILE *stream); 关闭指定的文件流，冲洗所有数据。

int fprintf(FILE *stream, const char *format, ...);

格式化不同类项的参数，并写入到指定的文件流（sprintf写到指定的字符串，printf写到标准输出）。

char *fgets(char *s, int n, FILE *stream);

从文件流读取一个字符串，遇到以下情况停止：读到换行符；已经读入n-1个字符（因为需要加上表示结尾的空字符'\0'）；到达文件尾。

int fputs(const char *str, FILE *fp); 把一个以空字符终止的字符串写入到指定流，尾端的终止符不写。

curses库函数

该例程“使用curses函数函数库管理基于文本的屏幕”，即使用了非常多的curses库函数，管理屏幕输入/出、键盘输入、窗口/子窗口等。使用细节暂且不深究。

学习该例程的目的是，厘清使用C语言完成该程序的逻辑流程，及，与Shell的区别。

int getch(void); 获取键盘输入，

在cbreak()模式下，字符一旦键入，立刻传递给程序，不需要回车，所以不需要处理回车带来的'\n';

在预处理模式（cooked）下，由于所有处理基于行，没有按回车时程序被阻塞。

******************************************************************************/

#include <unistd.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <curses.h>

#define MAX_STRING 80

#define MAX_ENTRY 1024

#define MESSAGE_LINE 6

#define ERROR_LINE 22

#define Q_LINE 20

#define PROMPT_LINE 18

static char current_cd[MAX_STRING] = "\0";

static char current_cat[MAX_STRING];

const char *TITLE_FILE = "title.cdb";

const char *TRACKS_FILE = "tracks.cdb";

const char *temp_file = "cdb.tmp";

void clear_all_screen(void);

void get_return(void);

int get_confirm(void);

int getchoice(char *greet, char *choices[]);

void draw_menu(char *options[], int highlight, int start_row, int start_col);

void insert_title(char *cdtitle);

void get_string(char *string);

void add_record(void);

void count_cds(void);

void find_cd(void);

void list_tracks(void);

void remove_tracks(void);

void remove_cd(void);

void update_cd(void);

//todo why aadd? Repeat the first letter?

char *main_menu[] =

{

"aadd new CD",

"ffind CD",

"ccount CDs and tracks in the catalog",

"qquit",

0,

};

char *extended_menu[] =

{

"aadd new CD",

"ffind CD",

"ccount CDs and tracks in the catalog",

"l list tracks on current CD",

"r remove current CD",

"u update track information",

"qquit",

0,

};

int main()

{

int choice;

initscr();

do {

/* 当current_cd 不为'\0'时，需要重绘为扩展菜单 */

choice = getchoice("Options:", current_cd[0] ? extended_menu : main_menu);

switch (choice) {

case 'q':

break;

case 'a':

add_record();

break;

case 'c':

count_cds();

break;

case 'f':

find_cd();

break;

case 'l':

list_tracks();

break;

case 'r':

remove_cd();

break;

case 'u':

update_cd();

break;

}

} while (choice != 'q');

endwin();

exit(EXIT_SUCCESS);

}

int getchoice(char *greet, char *choices[])

{

static int selected_row = 0;

int max_row = 0;

int start_screenrow = MESSAGE_LINE;

int start_screencol = 10;

char **option;

int selected;

int key = 0;

option = choices;

while (*option) {

max_row++;

option++;

}

/* project against menu getting shorter when CD deleted */

if (selected_row >= max_row){

selected_row = 0;

}

clear_all_screen();

mvprintw(start_screenrow - 2, start_screencol, greet);

keypad(stdscr, TRUE);

cbreak();

noecho();

key = 0;

while (key != 'q' && key != KEY_ENTER && key != '\n') {

if (key == KEY_UP) {

if (selected_row == 0) {

selected_row = max_row - 1;

} else {

selected_row--;

}

}

if (key == KEY_DOWN){

if (selected_row == (max_row - 1)) {

selected_row = 0;

} else {

selected_row++;

}

}

selected = *choices[selected_row];

draw_menu(choices, selected_row, start_screenrow, start_screencol);

key = getch();

}

keypad(stdscr, FALSE);

nocbreak();

echo();

if (key == 'q') {

selected = 'q';

}

return (selected);

}

void draw_menu(char *options[], int current_highlight,

int start_row, int start_col)

{

int current_row = 0;

char **option_ptr;

char *txt_ptr;

option_ptr = options;

while (*option_ptr) {

if (current_row == current_highlight) {

attron(A_STANDOUT);

}

txt_ptr = options[current_row];

txt_ptr++;

mvprintw(start_row + current_row, start_col, "%s", txt_ptr);

if (current_row == current_highlight) {

attroff(A_STANDOUT);

}

current_row++;

option_ptr++;

}

mvprintw(start_row + current_row + 3, start_col, "Move highlight then press Return ");

refresh();

}

void clear_all_screen()

{

clear();

mvprintw(2, 20, "%s", "CD Database Application");

if (current_cd[0]) {

mvprintw(ERROR_LINE, 0, "Current CD: %s, %s\n",

current_cat, current_cd);

}

refresh();

}

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(PROMPT_LINE-2, 5, "%s", "About to add this new entry");

sprintf(cd_entry, "%s,%s,%s,%s", catalog_number, cd_title, cd_type, cd_artist);

mvprintw(PROMPT_LINE, 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);

}

}

void get_string(char *string)

{

int len;

wgetnstr(stdscr, string, MAX_STRING);

len = strlen(string);

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

string[len - 1] = '\0';

}

}

int get_confirm()

{

int confirmed = 0;

char first_char;

mvprintw(Q_LINE, 5, "Are you sure?");

clrtoeol();

refresh();

cbreak();

first_char = getch();

if (first_char == 'Y' || first_char == 'y') {

confirmed = 1;

}

nocbreak();

if (!confirmed) {

mvprintw(Q_LINE, 1, " Cancelled");

clrtoeol();

refresh();

sleep(1);

}

return confirmed;

}

void insert_title(char *cdtitle)

{

FILE *fp = fopen(TITLE_FILE, "a");

if (!fp) {

mvprintw(ERROR_LINE, 0, "cannot open CD titles database");

} else {

fprintf(fp, "%s\n", cdtitle);

fclose(fp);

}

}

#define BOXED_LINES 11

#define BOXED_ROWS 60

#define BOX_LINE_POS 8

#define BOX_ROW_POS 2

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 {

//todo mvprintw

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);

}

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;

}

//todo whey current_cd remove all?

cat_length = strlen(current_cat);

/* Copy the titles file to a tempory, 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';

}

void remove_tracks()

{

FILE *tracks_fp, *temp_fp;

char entry[MAX_ENTRY];

int cat_length;

if (current_cd[0] == '\0') {

return;

}

//todo whey current_cd remove all?

cat_length = strlen(current_cat);

tracks_fp = fopen(TRACKS_FILE, "r");

if (tracks_fp == (FILE *)NULL) {

return;

}

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);

/* Delete the tracks file, and rename the temporary file */

unlink(TRACKS_FILE);

rename(temp_file, TRACKS_FILE);

}

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();

}

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();

}

}

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.");

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);

key = getch();

}

delwin(track_pad_ptr);

keypad(stdscr, FALSE);

nocbreak();

echo();

}

void get_return()

{

int ch;

mvprintw(23, 0, "%s", "Press return");

refresh();

while ((ch = getchar()) != '\n' && ch != EOF)

;

}