#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <time.h>
#include <unistd.h>
#include <stdio.h>

#define STRINGIFY(x) #x
#define TOSTRING(x) STRINGIFY(x)
#define HERE __FILE__ "(" TOSTRING(__LINE__) "): "

//Macro for automatic perror/throw inside a class
#define CLERROR(cmd, x)				\
	{								\
		if ((int)(x) == -1)			\
		{							\
			perror(HERE cmd);		\
			throw HERE cmd;			\
		}							\
	}

//Macro for automatic perror/return inside a function
#define FNERROR(cmd, x, retVal)		\
	{								\
		if ((int)(x) == -1)			\
		{							\
			perror(HERE cmd);		\
			return retVal;			\
		}							\
	}

//Macro for automatic perror/exit
#define ERROR(cmd, x)				\
	{								\
		if ((int)(x) == -1)			\
		{							\
			perror(HERE cmd);		\
			return -1;				\
		}							\
	}

#define SEM_MUTEX 0
#define SEM_WRITE 1
#define SEM_QUEUE 2

#define SHM_SIZE 1024+sizeof(int)

void milliSleep(int millisecs);


union semun
{
     int val;
     struct semid_ds *buf;
     unsigned short int *array;
     struct seminfo *__buf;
};

class SysSemaphores
{
	int sem_id;

	struct sembuf wait_buf;
	struct sembuf signal_buf;

public:
	SysSemaphores(int number, int flags)
	{
		CLERROR("SysSemaphores(): semget", sem_id = semget(IPC_PRIVATE, number, flags));
		wait_buf.sem_op  = -1;
		wait_buf.sem_flg =  0;
		signal_buf.sem_op  = 1;
		signal_buf.sem_flg = 0;
	}

	int getId() { return sem_id; }

	int SetVal(ushort semnum, int value)
	{
		union semun theSemun;

		theSemun.val = value;
		return semctl(sem_id, semnum, SETVAL, theSemun);
	}

	int Wait(ushort semnum)
	{
		wait_buf.sem_num = semnum;
		return semop(sem_id, &wait_buf, 1);
	}

	int Signal(ushort semnum)
	{
		signal_buf.sem_num = semnum;
		return semop(sem_id, &signal_buf, 1);
	}

	~SysSemaphores()
	{
		if (sem_id != -1)
		{
			semctl(sem_id, 0, IPC_RMID, 0);
			sem_id = -1;
		}
	}
};

class SysSharedMem
{
	int shm_id;

public:
	SysSharedMem(int size, int flags)
	{
		CLERROR("SysSharedMem(): shmget", shm_id = shmget(IPC_PRIVATE, size, flags));
	}

	int getId() { return shm_id; }

	void *Attach(int flags)
	{
		return shmat(shm_id, NULL, flags);
	}

	int Detach(void* addr)
	{
		return shmdt(addr);
	}

	~SysSharedMem()
	{
		if (shm_id != -1)
		{
			shmctl(shm_id, IPC_RMID, 0);
			shm_id = -1;
		}
	}
};


void WriterFunction(SysSemaphores *pSems, char *shmPtr);
void ReaderFunction(SysSemaphores *pSems, char *shmPtr);
long getTime();