// Sat Mar 25 16:35:53 CET 2000
// (c) Dinko Korunic, 36355514, kreator@fly.srk.fer.hr
// Zadatak 3 iz predmeta Operacijski sustavi 1
// Ostvariti suradnju paralelnih procesa koristenjem zajednicke memorije

// Opis rjesenja:
//	U prvom algoritmu nema iskljucivanja pa nije ni potrebno koristiti
//	zajednicku memoriju (naprosto imamo vise procesa koji rade
//	istovremeno), te je rezultat nedefiniran. U drugom i trecem
//	algoritmu vrsi se iskljucivanje procesa. Drugi proces iskljucuje
//	dva procesa, dok treci iskljucuje i vise od dva procesa.

#include <iostream.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#define LONG_MAX 2147483647

void MyIspis(int *i, int *k, int *m)
{
	cout << "i=" << *i << " k=" << *k << " m=" << *m << endl;
	usleep(1);
}

class NormalProc
{
	int BrojProcesa;
	void MyProc(int i);
	public:
		NormalProc(int i);
};

NormalProc::NormalProc(int i=3) : BrojProcesa(i)
{
	cout << "Rad bez medjusobnog iskljucivanja\n" 
		"i bez zajednicke memorije" << endl;
	int k;
	for (k=0; k<BrojProcesa; ++k)
	{
		if (!fork())
		{
			MyProc(k);
			_exit(EXIT_SUCCESS);
		}	
	}
	for (k=0; k<BrojProcesa; ++k) wait(NULL);
}

void NormalProc::MyProc(int i)
{
	int m, k;
	for (k=1; k<=5; ++k)
		for (m=1; m<=10; ++m)
		{
			MyIspis(&i, &k, &m);
		}
}

struct Dekker_t
{
	int Pravo;
	int Zastavica[2];
};

class DekkerProc
{
	int BrojProcesa;
	int MySegid;
	Dekker_t *MyDekkerStruct;
        void MyProc(int i);                                                     
	public:
		DekkerProc(int i);
};

DekkerProc::DekkerProc(int i=2) : BrojProcesa(i)
{
	cout << "Dekkerov algoritam za dva procesa" << endl;
	MySegid=shmget(IPC_PRIVATE, sizeof(Dekker_t), 6*8*8);
	MyDekkerStruct=(Dekker_t *)shmat(MySegid, NULL, 0);
	MyDekkerStruct->Pravo=1;
	int k;
	for (k=0; k<BrojProcesa; ++k)
	{
		if (!fork())
		{
			MyProc(k);
			_exit(EXIT_SUCCESS);
		}	
	}
	for (k=0; k<BrojProcesa; ++k) wait(NULL);
	cout << "Brisem zajednicku memoriju" << endl;
	shmdt((char *)MyDekkerStruct);
	shmctl(MySegid, IPC_RMID, NULL);
}

void DekkerProc::MyProc(int i)
{
	int j, k, m;
	for (k=1; k<=5; ++k)
	{
		MyDekkerStruct->Zastavica[i]=1;
		j=1-i;
		while (MyDekkerStruct->Zastavica[j])
		{
			if (MyDekkerStruct->Pravo==j)
			{
				MyDekkerStruct->Zastavica[i]=0;
				while (MyDekkerStruct->Pravo==j);
				MyDekkerStruct->Zastavica[i]=1;
			}
		}
		for (m=1; m<=10; ++m)
		{
			MyIspis(&i, &k, &m);
		}
		MyDekkerStruct->Pravo=j;
		MyDekkerStruct->Zastavica[i]=0;
	}
}

struct Lamport_t
{
	int Trazim[3];
	int Broj[3];
};

class LamportProc
{
	int BrojProcesa;
	int MySegid;
	Lamport_t *MyLamportStruct;
	void MyProc(int i);
	int MyMax(int BrojP, int *Ptr);
	public:
		LamportProc(int i);
};

LamportProc::LamportProc(const int i=3) : BrojProcesa(i)
{
	cout << "Lamportov algoritam za >2 procesa." << endl;
	MySegid=shmget(IPC_PRIVATE, sizeof(Lamport_t), 6*8*8);
	MyLamportStruct=(Lamport_t *)shmat(MySegid, NULL, 0);
	int k;
	for (k=0; k<BrojProcesa; ++k)
	{
		if (!fork())
		{
			MyProc(k);
			_exit(EXIT_SUCCESS);
		}	
	}
	for (k=0; k<BrojProcesa; ++k) wait(NULL);
	cout << "Brisem zajednicku memoriju" << endl;
	shmdt((char *)MyLamportStruct);
	shmctl(MySegid, IPC_RMID, NULL);
}

void LamportProc::MyProc(int i)
{
	int j, k, m;
	for (k=1; k<=5; ++k)
	{
		MyLamportStruct->Trazim[i]=1;
		MyLamportStruct->Broj[i]=MyMax(BrojProcesa,
				MyLamportStruct->Broj)+1;
		MyLamportStruct->Trazim[i]=0;
		for (j=0; j<BrojProcesa; ++j)
		{
			while (MyLamportStruct->Trazim[j]);
			while (MyLamportStruct->Broj[j] &&
			(MyLamportStruct->Broj[j]<MyLamportStruct->Broj[i] ||
			(MyLamportStruct->Broj[j]==MyLamportStruct->Broj[i] &&
				j<i)));
		}
		for (m=1; m<=10; ++m)
		{
			MyIspis(&i, &k, &m);
		}
		MyLamportStruct->Broj[i]=0;
	}
}

int LamportProc::MyMax(int BrojP, int *Ptr)
{
	int maxx=Ptr[0];
	for (int i=1; i<BrojP; ++i) if (Ptr[i]>maxx) maxx=Ptr[i];
	return maxx;
}

void MyClean(int i)
{
	for (i=1; i<LONG_MAX; ++i)
	{
		if (shmctl(i, IPC_RMID, NULL)!=-1)
			cout << "Obrisao zajednicku memoriju " << i <<
					endl;
		if (semctl(i, 0, IPC_RMID, 0)!=-1)
			cout << "Obrisao skup semafora " << i << endl;
		if (msgctl(i, IPC_RMID, NULL)!=-1)
			cout << "Obrisao red poruka " << i << endl;
	}
	cout << "Izlazim iz programa" << endl;
	exit(EXIT_SUCCESS);
}

int main(int argc, char *argv[])
{
	signal(SIGINT, MyClean);
	if (argc==2)
	{	
		if (*argv[1]=='1') NormalProc MyNormalProc;
		else if (*argv[1]=='2') DekkerProc MyDekkerProc;
		else LamportProc MyLamportProc;
	}
	return EXIT_SUCCESS;
}