termfuncs.cpp

#include <iostream>
#include <termios.h>
#include <unistd.h>
#include <stdlib.h>
#include <time.h>
#include <signal.h>
#include <ctype.h>
using namespace std;
#include "termfuncs.h"

//
// TERMFUNCS.CPP Version: 2015-07-09
//
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
//   NOTE: getachar and getacharnow handle arrow keys by returning
//	   KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT
//
//   KLUDGE: if $TF_QUIT is defined then getachar will exit if that 
//	     key is entered (total hack, I know)
//
//   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: 2015-11-02 spcial TF_QUIT key for exit on a char
// hist: 2015-11-02 handle EOF for getachar
// hist: 2015-07-09 added arrow key handling
// 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;

static char handle_escape_seq();

//
// getachar
//  returns a char using noecho and -icanon unless not a tty
//
char getachar()
{
	char q_key = 0;
	char *qk = NULL;
	char c;
	int  nread;

	if ( ( qk = getenv("TF_QUIT") ) != NULL ){
		q_key = qk[0];
	}
	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);

		nread = read(0, &c, 1);
		if ( nread == 1 && c == ESCAPE )
			c = handle_escape_seq();

		// system("stty echo icanon");
		tcsetattr(0, TCSANOW, &orig);
	}
	else {
		if ( cin.get(c) )
			nread = 1;
		else
			nread = 0;
		// cout << "got " << nread << " chars [" << c << "]\n";
		if ( nread == 0 && qk != NULL )
			exit(0);
	}

	if ( nread == 1 && qk != NULL && c == q_key ){
		exit(0);
	}

	return ( nread > 0 ? c : 0 );
}
//
// 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 ){
			if ( c == ESCAPE )
				c = handle_escape_seq();
		}
		else
			c = '\0';

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

	return (int) c;
}

//
// ignore signals, then set tty to read in up to 100 chars in 1/10 second
// examine sequence and return code
// Note: read until an alpha char or inactivity
//
char handle_escape_seq()
{
	struct termios	info, orig;
	char		buf[100];
	int		pos = 0;
	char		c;
	void		(*oldhand)(int);

	if ( !isatty(0) ) 
		return ESCAPE;

	oldhand = signal(SIGINT, SIG_IGN);

	// system("stty -echo -icanon");
	tcgetattr(0, &info);
	orig = info;

	info.c_lflag &= ~ECHO;
	info.c_lflag &= ~ICANON;
	info.c_cc[VMIN] = 0;
	info.c_cc[VTIME] = 1;			// 1/10 second
	tcsetattr(0, TCSANOW, &info);

	do
	{
		if ( read(0, &c, 1) == 1 )	// if got one
			buf[pos++] = c;		// store it
		else
			break;			// else timeout
	}
	while( !isalpha((int)c) && pos < 99 );	// until alpha or full

	if ( pos == 0 || (buf[0] != '[' && buf[0] != 'O' ) )
		c = ESCAPE;
	else 
		switch(buf[1]){
			case 'A':		c = KEY_UP;	break;
			case 'B':		c = KEY_DOWN;	break;
			case 'C':		c = KEY_RIGHT;	break;
			case 'D':		c = KEY_LEFT;	break;
			default :
						c = ESCAPE;
		}

	tcsetattr(0, TCSANOW, &orig);
	signal(SIGINT, oldhand);
	// system("stty echo icanon");
	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 );
}