termfuncs.cpp

/* modified by: Michael Edegware                                                *
 * Date: 3/26/2016                                                             *
 * Joke: Q. A programmer was going for work, so his wife told him that while he
 *       is out, he should get some decorations for her. He never came back.  
 */
#include <iostream>
#include <termios.h>
#include <unistd.h>
#include <stdlib.h>
#include <time.h>
#include <signal.h>
using namespace std;

static const string CSI = "\033[";

// -- NOTE TO COMP11 STUDENTS ----------------
//
//  DO NOT EDIT OR COPY CODE FROM THIS FILE
//  TO USE THESE FUNCTIONS:
//     at the top of your code put: #include "termfuncs.h"
//     when you compile:  g++ -Wall myprog.cpp termfuncs.cpp
//
//  DO NOT DO THIS:
//      #include "termfuncs.cpp"
//
//
// termfuncs.cpp -- some simple functions for using the terminal nicely
//
//   char getachar()     -- returns next char with no echo and no Enter needed
//   char getacharnow(ds)     -- only waits ds/10th seconds
//                               returns '\0' if no input by that time
//   void screen_clear() -- clears the screen
//   void screen_home()  -- moves cursor to top of screen
//   void screen_fg(string color)
//   void screen_bg(string color)
//   void screen_attr(string attr)
//   void screen_bright()
//   void screen_reset()
//   void place_cursor(int, int);   -- move the cursor to row col
//   void place_char(char, int, int)  -- move and place
//   void hide_cursor()
//   void show_cursor()
//
//   int  random_int(int low, int high)
//              returns random int in [low, high]
//              note: if SNAKE_SEED is set then use that for srand
//                    if not, then call srand with time(0) at first call
//   void seed_random(s)
//
// hist: 2014-09-30 added flush to getachar* and also show_cursor sighandler
// hist: 2014-09-30 added hide/show cursor and random_int
// hist: 2014-07-20 getachar now uses read, not cin >> c which skipped blanks
// hist: 2014-07-01 merged screendraw and termfuncs
//
static string color_names[] = { "black", "red", "green", "yellow",
                                "blue",  "magenta", "cyan", "white" };
static const int num_colors = 8;

static string attr_names[] = {  "reset", "bright", "dim", "",
                                "underscore", "blink", "",
                                "reverse", "hidden" };
static const int num_attrs = 9;

static termios prev_tty_state;
static int prev_state_stored = 0;

//
// getachar
//  returns a char using noecho and -icanon unless not a tty
//
char getachar()
{
        char c;

        cout << std::flush;
        if ( isatty(0) ){
                struct termios  info, orig;
                // system("stty -echo -icanon");
                tcgetattr(0, &info);
                orig = info;
                prev_tty_state = orig;
                prev_state_stored = 1;

                info.c_lflag &= ~ECHO;
                info.c_lflag &= ~ICANON;
                tcsetattr(0, TCSANOW, &info);

                read(0, &c, 1);

                // system("stty echo icanon");
                tcsetattr(0, TCSANOW, &orig);
        }
        else {
                read(0, &c, 1);
        }

        return c;
}
//
// getacharnow
//  returns a char using noecho and -icanon unless not a tty
//
char getacharnow(int decisecs)
{
        char c;

        cout << std::flush;
        if ( isatty(0) )
        {
                struct termios  info, orig;
                // system("stty -echo -icanon");
                tcgetattr(0, &info);
                orig = info;
                prev_tty_state = orig;
                prev_state_stored = 1;

                info.c_lflag &= ~ECHO;
                info.c_lflag &= ~ICANON;
                info.c_cc[VMIN] = 0;
                info.c_cc[VTIME] = decisecs;
                tcsetattr(0, TCSANOW, &info);

                if ( read(0, &c, 1) != 1 )
                        c = '\0';

                tcsetattr(0, TCSANOW, &orig);
                // system("stty echo icanon");
        }
        else {
                if ( read(0, &c, 1) != 1 )
                        c = '\0';
        }

        return c;
}


static void restore_tty_state()
{
        if ( prev_state_stored )
                tcsetattr(0, TCSANOW, &prev_tty_state);
}
void screen_clear()
{
        cout << (CSI + "H");
        cout << (CSI + "2J");
}

void screen_home()
{
        cout << (CSI + "H");
}

static  void (*prev_handler)(int) = NULL;;

void hide_cursor()
{
        void on_sigint(int);

        prev_handler = signal(SIGINT, on_sigint);
        cout << (CSI + "?25l");
}

void show_cursor()
{
        cout << (CSI + "?25h");
}

void on_sigint(int s)
{
        cout << std::flush;
        show_cursor();
        if ( prev_handler ){
                prev_handler(s);
        }
        restore_tty_state();
        exit(SIGINT);
}
//
// lookup a string in an array
//   args: string to find, list of strings, len of list
//   rets: index of string or -1 for not found
//
static int lookup(string findme, string list[], int num)
{
        int     i;
        for(i=0;i<num;i++)
        {
                if ( list[i] == findme )
                        return i;
        }
        return -1;
}
void screen_fg(string color)
{
        int     num = lookup(color, color_names, num_colors);
        if ( num >= 0 ){
                cout << CSI << ( 30 + num ) << "m";
        }
}
void screen_bg(string color)
{
        int     num = lookup(color, color_names, num_colors);
        if ( num >= 0 ){
                cout << CSI << ( 40 + num ) << "m";
        }
}
void screen_attr(string attr)
{
        int     num = lookup(attr, attr_names, num_attrs);
        if ( num >= 0 ){
                cout << CSI << num  << "m";
        }
}
void screen_bright()
{
        screen_attr("bright");
}
void screen_reset()
{
        screen_attr("reset");
}
void place_cursor(int row, int col)
{
        cout << "\033[" << (row+1) << ";" << (col+1) << "H";
        flush(cout);
}
void place_char(char c, int row, int col)
{
        place_cursor(row, col);
        cout << c;
        flush(cout);
}

static int rand_seed = -1;

void seed_random(int s)
{
        if ( s > 0 ){
                srand(s);
                rand_seed = s;
        }
}

int random_int(int lo, int hi)
{
        int     range = hi - lo + 1;
        char    *seed_str;

        if ( rand_seed == -1 ){
                seed_str = getenv( "SNAKE_SEED" );
                if ( seed_str != NULL )
                        seed_random( (unsigned) atoi(seed_str) );
                else
                        seed_random( (unsigned) time(NULL) );
        }
        if ( range <= 0 )
                return 17;              // add to function specs

        return lo + ( rand() % range );
}