[+] OLD STUFF 286: C POINTERS - CIRCULAR DOUBLY LINKED LIST

A Simple Selection Menu in C with Ansi functions.
This time I'm working on creating a circular list with pointers so as to display choice menus in C using colors to highlight the items.
In my implementation, I have used 3 external global pointers (head, former and tail). That probably means that I can only create one list as these pointers are global variables.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <sys/ioctl.h>

/*
   Last modified : 19/9/2017
   Coded by Velorek.
   Some of the terminal routines from:
   https://stackoverflow.com/questions/7469139/what-is-equivalent-to-getch-getche-in-linux
   Circular linked list to
   make a selection menu in C.
   Target OS: Linux.
*/

// Background colors low intensity                                                                         
#define B_BLACK 40
#define B_RED 41
#define B_GREEN 42
#define B_YELLOW 43
#define B_BLUE 44
#define B_MAGENTA 45
#define B_CYAN 46
#define B_WHITE 47

// Foreground colors low intensity                                                                                                                                 
#define F_BLACK 30
#define F_RED 31
#define F_GREEN 32
#define F_YELLOW 33
#define F_BLUE 34
#define F_MAGENTA 35
#define F_CYAN 36
#define F_WHITE 37

// Background colors high intensity                                                                                                                                     
#define BH_BLACK 100
#define BH_RED 101
#define BH_GREEN 102
#define BH_YELLOW 103
#define BH_BLUE 104
#define BH_MAGENTA 105
#define BH_CYAN 106
#define BH_WHITE 107

// Foreground colors high intensity                                                                                                                                     
#define FH_BLACK 90
#define FH_RED 91
#define FH_GREEN 92
#define FH_YELLOW 93
#define FH_BLUE 94
#define FH_MAGENTA 95
#define FH_CYAN 96
#define FH_WHITE 97

#define TRUE 1
#define FALSE 0
typedef int BOOL;

/* Global Variables */

struct winsize max;
static struct termios old, new;
int rows, columns, old_rows, old_columns;

typedef struct _listchoice
{
  int index; // Item number
  int backcolor0; // Back and Fore colors when not selected
  int forecolor0;
  int backcolor1; // Back and Fore colors when selected
  int forecolor1;
  int wherex; // Position of the item
  int wherey;
  char *item; // Item string
  struct _listchoice *next; // Pointer to next item
  struct _listchoice *back; // Pointer to previous item.
} LISTCHOICE;

LISTCHOICE *head=NULL;
LISTCHOICE *tail=NULL;
LISTCHOICE *former=NULL;
LISTCHOICE *mylist=NULL;

/* Terminal manipulation routines */

void gotoxy(int x,int y)
//Sets the cursor at the desired position.
{
  printf("%c[%d;%df",0x1B,y,x);
}

void outputcolor(int foreground, int background)
//Changes format foreground and background colors of display.
{
  printf("%c[%d;%dm", 0x1b,foreground,background);
}

void screencol(int x)
{
//change color of entire screen
  gotoxy(0,0);
  outputcolor(0,x);
  printf("%c[2J", 0x1b);
  outputcolor(0,0);
}

/* Initialize new terminal i/o settings */
void initTermios(int echo) 
{
  tcgetattr(0, &old); /* grab old terminal i/o settings */
  new = old; /* make new settings same as old settings */
  new.c_lflag &= ~ICANON; /* disable buffered i/o */
  new.c_lflag &= echo ? ECHO : ~ECHO; /* set echo mode */
  tcsetattr(0, TCSANOW, &new); /* use these new terminal i/o settings now */
}

/* Restore old terminal i/o settings */
void resetTermios(void) 
{
  tcsetattr(0, TCSANOW, &old);
}

/* Read 1 character - echo defines echo mode */
char getch_(int echo) 
{
  char ch;
  initTermios(echo);
  ch = getchar();
  resetTermios();
  return ch;
}

/* Read 1 character without echo */
char getch(void) 
{
  return getch_(0);
}

/* Read 1 character with echo */
char getche(void) 
{
  return getch_(1);
}

int get_terminal_dimensions(int *rows, int *columns)
{
//Get dimensions of screen by value.
  ioctl(0, TIOCGWINSZ , &max);
  *columns = max.ws_col;
  *rows = max.ws_row;
return 0;
}

/* Dynamic List routines */

void add_item(LISTCHOICE *list_identifier, char *str, int x, int y,int bcolor0, int fcolor0, int bcolor1, int fcolor1)
{
  LISTCHOICE *newp;
  if (head == NULL && list_identifier == NULL)
    {
      //Reserve memory
      list_identifier = (LISTCHOICE *) malloc(sizeof(LISTCHOICE));
      head = list_identifier;
      tail = list_identifier;
  
      //Create first item of the list and assign properties to it.
      list_identifier->backcolor0 = bcolor0;
      list_identifier->backcolor1 = bcolor1;
      list_identifier->forecolor0 = fcolor0;
      list_identifier->forecolor1 = fcolor1;
      list_identifier->wherex = x;
      list_identifier->wherey = y;
      list_identifier-> item = (char *)malloc(strlen(str) +1);
      strcpy(list_identifier->item, str);
      list_identifier->next = head;
      list_identifier->back = head;
      list_identifier->index = 0;
    }
  else
    {
      //Circular list structure
      newp = (LISTCHOICE *) malloc(sizeof(LISTCHOICE));
      former = tail; //former pointer points to previous-last item
      former->next = newp; //previous item forward points to current item
      newp->back = former; //new item back points to previous-last item
      tail = newp; //the tail now 'becomes' (points to) the new item
      head->back = tail; // This way we close the circular list : First item back points to last item
      tail->next = head; // Last item next points to first item.

      //Creates subsequent items of the list and assign properties to it.
      newp->backcolor0 = bcolor0;
      newp->backcolor1 = bcolor1;
      newp->forecolor0 = fcolor0;
      newp->forecolor1 = fcolor1;
      newp->wherex = x;
      newp->wherey = y;
      newp->item = (char*) malloc(strlen(str) + 1);
      strcpy(newp->item, str);
      newp->index = former->index + 1;
    }

}
void free_list(LISTCHOICE *list_identifier)
{
/* removes list from memory */
  LISTCHOICE *aux, *p;
  aux = tail;
  do
   {
     p=aux;
     aux = aux->back;
     free(p->item); //free off the string field
     free(p); //remove item  
   } while (aux != head->back);
}

void move_up(LISTCHOICE *aux)
{
  //Unmark Former Item
  gotoxy(aux->wherex,aux->wherey);
  outputcolor(aux->forecolor0,aux->backcolor0);
  printf("%s\n", aux->item);

  //Highlight current item
  *aux=*aux->back; //Go to previous item
  gotoxy(aux->wherex,aux->wherey);
  outputcolor(aux->forecolor1,aux->backcolor1);
  printf("%s\n", aux->item);
}

void move_down(LISTCHOICE *aux)
{
  //Unmark Former Item
  gotoxy(aux->wherex,aux->wherey);
  outputcolor(aux->forecolor0,aux->backcolor0);
  printf("%s\n", aux->item);

  //Highlight current item
  *aux=*aux->next; //Go to next item

  gotoxy(aux->wherex,aux->wherey);
  outputcolor(aux->forecolor1,aux->backcolor1);
  printf("%s\n", aux->item);
}

void display_list()
{
/*
Displays the items contained in the list with the properties specified
in init_list.
until the auxiliary pointer reaches the first item again
First item is equal to tail->next.
*/

  LISTCHOICE *aux;
  aux = head;
  do
   {
     gotoxy(aux->wherex,aux->wherey);  
     outputcolor(aux->forecolor0,aux->backcolor0); 
     printf("%s\n", aux->item);
     aux = aux->next;
   } while (aux != tail->next);
}

void start_vmenu(LISTCHOICE *list_data)
{
  /* Starts the selection menu */
  char ch;
  LISTCHOICE aux;
 
  display_list(); //display whole list

  //Highlight first item on the list
  aux=*tail; //Auxiliary variable points to last item
  move_down(&aux); //Move down to point to highlight first item.
  ch=0; // reset and initialise ch value  
  
  while (ch != 10) // enter key
    {
      ch=getch();
      if (ch=='\033') // escape key
 {
   getch(); // read key again for arrow key combinations
   switch(getch()) 
     {
     case 'A': // escape key + A => arrow key up
       move_up(&aux);
       break;
     case 'B': // escape key + B => arrow key down
       move_down(&aux);
       break;
     }
 }
    }
      if (ch==10) // enter key
 {
   //Pass data of last item by value.
   *list_data = aux;
 }

}

int main_screen()
{
//Draws the main screen

  int i,j;
  //Draw the main screen
  rows=0;
  columns=0;
  screencol(B_BLUE);
  gotoxy(1,1);
  outputcolor(0,F_WHITE);

  //Save previous values
  old_rows = rows;
  old_columns = columns;
  get_terminal_dimensions(&rows,&columns);

  if (rows==0) rows=25; //just in case it can't find the terminal dimensions
  if (columns==0) columns=80;
  
  //Draw upper and lower bars
  outputcolor(F_WHITE,B_CYAN);
  for (i=0;i<=columns;i++)
  {
    gotoxy(i,1);
    printf(" ");
  }

  outputcolor(F_WHITE,B_WHITE);
  for (i=0;i<=columns;i++)
  {
    gotoxy(i,rows);
    printf(" ");
  }
 
  outputcolor(F_BLACK,B_CYAN);
  gotoxy(1,1);
  printf(" File  Options  Help"); 
  outputcolor(FH_WHITE,B_BLUE);
  gotoxy(2,3);
  printf("Selection Menu");
  gotoxy(2,4);
  printf("==============");
  gotoxy(columns-6,1);
  outputcolor(FH_YELLOW,B_CYAN);
  printf("%d:%d",columns,rows);
  outputcolor(F_BLACK,B_WHITE);
  gotoxy(1,rows);
  printf("- Coded by Velorek");
}

int main()
{
  LISTCHOICE data;
  screencol(FH_BLUE);
  main_screen();
  add_item(mylist,"Option 1",3,6,B_BLUE,FH_WHITE,B_RED,F_WHITE);
  add_item(mylist,"Option 2",3,7,B_BLUE,FH_WHITE,B_RED,F_WHITE);
  add_item(mylist,"Option 3",3,8,B_BLUE,FH_WHITE,B_RED,F_WHITE);
  add_item(mylist,"Option 4",3,9,B_BLUE,FH_WHITE,B_RED,F_WHITE);
  add_item(mylist,"Option 5",3,10,B_BLUE,FH_WHITE,B_RED,F_WHITE);
  add_item(mylist,"Exit",3,11,B_BLUE,FH_WHITE,B_GREEN,F_WHITE);
  outputcolor(F_BLUE,B_BLACK);
  do {
    start_vmenu(&data);
    gotoxy(20,18);
    printf("You have selected: %i:%s\n",data.index+1,data.item);
  } while (strcmp(data.item,"Exit") != 0);
  free_list(mylist);
  screencol(B_BLACK);
  printf("\n");
  return 0;
}
Display:
[+] OLD STUFF 286

Tuesday, August 29, 2017

C POINTERS - CIRCULAR DOUBLY LINKED LIST

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