elevator_me.cc

linux的例子,就是下载后到自己的机子上去运行

#include"Elevator.h"
#include <malloc.h>

Elevator::Elevator(char *debugName,int numFloors,int myID)
{	
	int i;
	name = debugName;
	numfloors = numFloors;
	currentfloor = 1;
	elevstate = STOP;
	occupancy = 0;
	elevID = myID;
	fullnum = 20;
	dstfloor = new int[numfloors+1];
	elevlock = new Lock("elevtor lock");
	elevcond =(Condition **)malloc(sizeof(Condition*)*(numfloors+1));
	for(i=1;i<=numfloors;i++)
		elevcond[i] = new Condition("elevtor condition");
}

Elevator::~Elevator()
{
	delete dstfloor;
	delete elevlock;
	delete elevcond;
}	

void
Elevator::OpenDoors()
{
	elevlock->Acquire();
	elevcond[currentfloor]->Broadcast(elevlock);
	elevlock->Release();
	if(elevstate == UP)
	{
		(*people)=(*people)-upbarrier[currentfloor]->Waiters();
		upbarrier[currentfloor]->Signal();
	}
	else if(elevstate==DOWN)
	{
		(*people)=(*people)-downbarrier[currentfloor]->Waiters();
		downbarrier[currentfloor]->Signal();
	}
	dstfloor[currentfloor] = 0;
	elevlock->Acquire();
	elevcond[currentfloor]->Broadcast(elevlock);
	elevlock->Release();
}

void
Elevator::CloseDoors()
{
	if(occupancy==0)
		elevstate=STOP;
	return;
}

void
Elevator::VisitFloor(int floor)
{	
	if(currentfloor<floor)
		elevstate=UP;
	else if(currentfloor>floor)
		elevstate=DOWN;
	else{
		if((occupancy==0)&&(floor==0))
		elevstate=STOP;
	}
	currentfloor = floor;
}

int
Elevator::NextFloor()
{
	int u1,u2,d1,d2,i,j,result;
	while(1){
		u1=currentfloor;
		d2=currentfloor;
		i=currentfloor;
		j=currentfloor;
		u2=1;
		d1=numfloors;
		result=0;
		if(occupancy > 0)
		{
		 	while(j <= numfloors && !dstfloor[j++]);
			while(i >= 1 && !dstfloor[i--]);
			j--;i++;
		}
		else{
			j=numfloors+1;
			i=0;
		}
		while((u1<=numfloors) && !(upbarrier[u1++]->Waiters()));
		while((u2<=currentfloor) && !(upbarrier[u2++]->Waiters()));
		while((d1>=currentfloor) && !(downbarrier[d1--]->Waiters()));
		while((d2>=1) && !(downbarrier[d2--]->Waiters()));
		//printf("elevator %d currentfloor=%d\n",elevID,currentfloor);
		if(elevstate == UP|| elevstate==STOP )
		{
			if(u1 <= numfloors || j <= numfloors ){
				elevstate = UP;
				u1--;
				if(occupancy>0)
					result = (u1<=j)?u1:j;
				else if(u1==10)
					result = 0;
				else 
					result = u1;
			}
			else if(d1 >= currentfloor){
   				d1++;	
				elevstate = DOWN; 
				result =  d1;
			}
			else if(d2 >= 1){
				d2++;	
				elevstate = DOWN; 
				result = d2;
			}
			else if(u2 <= currentfloor){
				u2--;
				elevstate = UP;
				result = u2;
			}
		}
		else 
		{
			if(d2 >= 1 || i >= 1 ){
				d2++;
				elevstate = DOWN;
				if(occupancy>0)
					result = (d2>=i)?d2:i;
				else if(d2==1)
					result = 0;
				else
					result = d2;
			}
			else if(u2 <= currentfloor){
   				u2--;	
				elevstate = UP;
				 result = u2;
			}
			else if(u1 <= numfloors){
				u1--;	
				elevstate = UP; 
				result = u1;
			}
			else if(d1 >= currentfloor){
				d1++;
				elevstate=DOWN;
				result= d1;
			}
		}
		if(result==0){ 
			printf("elevator %d stop at floor %d.\n",elevID,currentfloor);
			while(1)
			{
				wait->P();
				if((*people)>0)
					break;
			}
			printf("elevator %d start.\n",elevID);
		}	
		else
			break;
	}
	return result;
}

bool
Elevator::Enter()
{
	if(occupancy < fullnum)
	{	
		++occupancy;
		return true;
	}
	else    return false;
}

void 
Elevator::Exit()
{
	--occupancy;
	if(occupancy==0)
		elevstate = STOP;
}

void
Elevator::RequestFloor(int floor)
{
	dstfloor[floor] = 1;
	elevlock->Acquire();
	elevcond[floor]->Wait(elevlock);
	elevlock->Release();
}

//////////////////////////////////////////////////////////////////////
Building::Building(char *debugname,int numFloors,int numElevators)
{
	name = debugname;
	numfloors = numFloors;
	numelevators = numElevators;
	int i;
	upbarrier =(EventBarrier**)malloc(sizeof(EventBarrier*)*(numfloors+1));
	for(i=1;i<=numfloors;i++)
		upbarrier[i] = new EventBarrier("up barrier");
	downbarrier=(EventBarrier**)malloc(sizeof(EventBarrier*)*(numfloors+1));
	for(i=1;i<=numfloors;i++)
		downbarrier[i] = new EventBarrier("down barrier");
	wait = new Semaphore("wait",0);
	elevator=(Elevator **)malloc(sizeof(Elevator*)*(numElevators+1));
	for(i=1;i<=numelevators;++i)
	{
		elevator[i]= new Elevator("elevator",numfloors,i);
		elevator[i]->init(upbarrier,downbarrier,wait,&people);
	}
}

Building::~Building()
{
	delete upbarrier;
	delete downbarrier;
	delete elevator;
}

void
Building::CallUp(int fromFloor)
{
	++people;
	wait->V();
}

void
Building::CallDown(int fromFloor)
{
	++people;
	wait->V();
}

Elevator*
Building::AwaitUp(int fromFloor)
{
	int i;
	upbarrier[fromFloor]->Wait();
	for(i=1;i<=numelevators;i++)
		if(elevator[i]->GetCurrentFloor()==fromFloor&&elevator[i]->GetState()==UP)
			return elevator[i];
	return 	NULL;
}

Elevator*
Building::AwaitDown(int fromFloor)
{
	int i;
	downbarrier[fromFloor]->Wait();
	for(i=1;i<=numelevators;i++)
		if(elevator[i]->GetCurrentFloor()==fromFloor&&elevator[i]->GetState()==DOWN)
			return elevator[i];
	return NULL;
}