as5_phil.pj

import std.*;
const int MAX = 5;

// void philosopher(int id, chan<boolean>.write left, chan<boolean>.write right) {
//     while (true) {
// 	    println(id + ": I am thinking");
// 	    par {                // pick up forks
// 	        left.write(true);   
// 	        right.write(true);
// 	    }
// 	    println(id + ": I am eating");
// 	    par {                // put down forks
//             left.write(true);
//             right.write(true);
// 	    }
//     }
// }

// fork is a reserved word for now, so use Fork
void Fork(int i, chan<boolean>.read left, chan<boolean>.read right) {
    boolean any;
    while (true) {
		alt {
			//right phil picks up
			any = left.read(): {  // This corresponds to forks_direction.left in FDR
				println(i + ": picked up from the right."); // This corresponds to forks_motion.up in FDR
				any = left.read();   // right phil puts down
				println(i + ": put down from the right.");  // This corresponds to forks_motion.down in FDR
			}
			// left phil picks up
			any = right.read(): {  
				println(i + ": picked up from the left."); // This corresponds to forks_motion.up in FDR
				any = right.read();  // left phil puts down
				println(i + ": put down from the left.");  // This corresponds to forks_motion.down in FDR    
			}
		}
    }
}

// void college() {
//     // I handcoded this for you - I didn't check I got
//     // it right, so you may wanna check that yourself ;-)
//     chan<boolean> left0, left1, left2, left3, left4;
//     chan<boolean> right0, right1, right2, right3, right4;
//     par {
// 		philosopher(0, left0.write, right0.write);
// 		philosopher(1, left1.write, right1.write);
// 		philosopher(2, left2.write, right2.write);
// 		philosopher(3, left3.write, right3.write);
// 		philosopher(4, left4.write, right4.write);
// 		Fork(0, left0.read, right1.read);
// 		Fork(1, left1.read, right2.read);
// 		Fork(1, left2.read, right3.read);
// 		Fork(1, left3.read, right4.read);
// 		Fork(2, left4.read, right0.read);
//     }
// }

void securePhilosopher(int id, chan<boolean>.write left, chan<boolean>.write right, 
							   chan<boolean>.write sitdown, chan<boolean>.write getup) {
    while (true) {
		println(id + ": I am thinking"); //This corresponds to think.i in FDR
		println(id + ": I want to sit down."); //This corresponds to sitdown.i in FDR
		// ask to sit down
		sitdown.write(true);    
		par {                // pick up forks
			left.write(true);   
			right.write(true);
		}
		println(id + ": I am eating"); //This corresponds to eat.i in FDR
		par {                // put down forks
			left.write(true);
			right.write(true);
		}
		println(id + ": I want to get up."); //This corresponds to getup.i in FDR
		// get up
		getup.write(true);      
    }
}


void security(chan<boolean>.read[] up, chan<boolean>.read[] down) {
    // up.length does not cause an error! 
    const int maxSatDown = up.size - 1;
    int satDown = 0;
    boolean any;
    while (true) {
    	println("Sat Down = " + satDown);
    	alt {
			(satDown < maxSatDown) && any = down[0].read(): satDown = satDown + 1;
			(satDown < maxSatDown) && any = down[1].read(): satDown = satDown + 1;
			(satDown < maxSatDown) && any = down[2].read(): satDown = satDown + 1;
			(satDown < maxSatDown) && any = down[3].read(): satDown = satDown + 1;
			(satDown < maxSatDown) && any = down[4].read(): satDown = satDown + 1;
			any = up[0].read(): satDown = satDown - 1;
			any = up[1].read():	satDown = satDown - 1;
			any = up[2].read():	satDown = satDown - 1;
			any = up[3].read():	satDown = satDown - 1;
			any = up[4].read():	satDown = satDown - 1;
		}
    }
}

void secureCollege() {
    // I handcoded this for you - I didn't check I got                                                                  
    // it right, so you may wanna check that yourself ;-)                                                               
    chan<boolean> left0, left1, left2, left3, left4;
    chan<boolean> right0, right1, right2, right3, right4;
    chan<boolean> down0, down1, down2, down3, down4;
    chan<boolean> up0, up1, up2, up3, up4;

    chan<boolean>.read[] ups = new chan<boolean>.read[5];
    chan<boolean>.read[] downs = new chan<boolean>.read[5];
    ups[0] = up0.read;
    ups[1] = up1.read;
    ups[2] = up2.read;
    ups[3] = up3.read;
    ups[4] = up4.read;
    downs[0] = down0.read;
    downs[1] = down1.read;
    downs[2] = down2.read;
    downs[3] = down3.read;
    downs[4] = down4.read;

    par {
		//securePhilosopher(i, left[i].write, right[i].write, down[i].write, up[i].write)
        securePhilosopher(0, left0.write, right0.write, down0.write, up0.write);
		securePhilosopher(1, left1.write, right1.write, down1.write, up1.write);
        securePhilosopher(2, left2.write, right2.write, down2.write, up2.write);
        securePhilosopher(3, left3.write, right3.write, down3.write, up3.write);
        securePhilosopher(4, left4.write, right4.write, down4.write, up4.write);

		// fork(left[i].read, right[(i+1)%max].read);
        Fork(0, left0.read, right1.read);
        Fork(1, left1.read, right2.read);
        Fork(2, left2.read, right3.read);
        Fork(3, left3.read, right4.read);
        Fork(4, left4.read, right0.read);

		security(ups, downs);
    }
}

public void main(string args[]) {
	//college();
	secureCollege(); 
}