static void ack ( int signalNumber )
// Mode d'emploi :
// Acknowledge the death of a children GarerParking tasks.
// Update the shared state and display accordingly.
{
// Retrieve the pid of the terminated child
int status;
pid_t pid;
// For each child task that has died
while ( (pid = waitpid ( -1, &status, WNOHANG )) > 0 )
{
if ( WIFEXITED ( status ) )
{
// Retrieve the spot number (encoded into the return value)
int spotNumber = WEXITSTATUS ( status );
Car car = currentValets[pid];
car.entranceTime = time ( NULL );
// Remove this pid from the list of running tasks
currentValets.erase ( pid );
// Update the state of the parking lot
placeCar ( spotNumber, car );
// Display the newly parked car
AfficherPlace ( spotNumber, car.priority,
car.licensePlate, car.entranceTime );
}
}
} // Fin de ack
/**
readIn
Reads in data from the standard in to initialize a game state using the given
data.
@pre
-# *this is a valid instantiation of a game state.
-# *this is a cleared games state to prevent data corruption, or at least this
function will perform the clearing operation.
@post
-# *this will contain the data of a valid game state.
@detail @bAlgorithm
-# *this is cleared.
-# The car data is read in sequentially.
-# The cars are then placed in the array
@code
@endcode
*/
void GameState::readIn()
{
// assert pre-conditions
assert( numCars > 0 );
// variables
int currentCar = 0;
// read in each vehicle's data
for( currentCar = 0; currentCar < numCars; currentCar++ )
{
// read in each piece of car data
cin >> carList[ currentCar ].length >> carList[ currentCar ].orientation
>> carList[ currentCar ].yPos >> carList[ currentCar ].xPos;
}
// place each car
for( currentCar = 0; currentCar < numCars; currentCar++ )
{
placeCar( currentCar, carList[currentCar].xPos, carList[currentCar].yPos );
}
// no return - void
}
/**
move
Modifies the game state to simulate the movement of a vehicle.
@param whichCar Which car in the current list is to be moved.
@param direction Which direction the car will attempt to move. Function should
be called using the constants given in GameState.h.
@return movementSuccess Indicates the success of the movement so that
decisions can be made. True for a successful movement,
false otherwise.
@pre
-# The GameState is in a valid state with legally placed cars.
@post
-# Cars will be in a valid state on the game board and the success of the
movement is returned.
@detail @bAlgorithm
-# Depending on the car and direction, the next array location the car will
occupy is computed.
-# This location is checked to see if it is in the bounds of the array.
-# The location is then checked to see if it is occupied already.
-# If the location is occupied, the car is placed on the new location and the
space previously occupied is cleaned up. True is returned to indicate a
successful movement.
-# If for any reason the move cannot be legally made, the attempt is abandoned
and false is returned.
@code
@endcode
*/
bool GameState::move( const int whichCar, const bool direction )
{
// variables
bool moveSuccess = false;
// case: moving forward
if( direction == FORWARD )
{
// case: car is vertical
if( carList[whichCar].orientation == kVertical )
{
// case: new index is valid
if( (carList[whichCar].yPos - 1) >= 0 )
{
// case: new index is empty
if( board[carList[whichCar].yPos - 1][carList[whichCar].xPos] == kEmpty )
{
// perform move (modifies car head values)
placeCar( whichCar, carList[whichCar].xPos, carList[whichCar].yPos - 1 );
// clean up behind the car
board[carList[whichCar].yPos + carList[whichCar].length]
[carList[whichCar].xPos] = kEmpty;
// update flag
moveSuccess = true;
}
}
}
// case: car is horizontal
else
{
// case: new index is valid
if( (carList[whichCar].xPos + carList[whichCar].length) < kBoardSize )
{
// case: new index is empty
if( ( board[carList[whichCar].yPos][carList[whichCar].xPos +
carList[whichCar].length] ) == kEmpty )
{
// perform move (modifies car head values)
placeCar( whichCar, carList[whichCar].xPos + 1, carList[whichCar].yPos );
// clean up behind the car
board[carList[whichCar].yPos][carList[whichCar].xPos - 1] = kEmpty;
// update flag
moveSuccess = true;
}
}
}
}
// case: moving backward
else
{
// case: car is vertical
if( carList[whichCar].orientation == kVertical )
{
// case: new index is valid
if( (carList[whichCar].yPos + carList[whichCar].length) < kBoardSize )
{
// case: new index is empty
if( ( board[carList[whichCar].yPos +
carList[whichCar].length][carList[whichCar].xPos] ) == kEmpty )
{
// perform move (modifies car head values)
placeCar( whichCar, carList[whichCar].xPos, carList[whichCar].yPos + 1 );
// clean up behind the car
board[carList[whichCar].yPos - 1][carList[whichCar].xPos] = kEmpty;
// update flag
moveSuccess = true;
}
}
}
// case: car is horizontal
else
{
// case: new index is valid
if( (carList[whichCar].xPos - 1) >= 0 )
{
// case: new index is empty
if( board[carList[whichCar].yPos][carList[whichCar].xPos - 1] == kEmpty )
{
// perform move (modifies car head values)
placeCar( whichCar, carList[whichCar].xPos - 1, carList[whichCar].yPos );
// clean up behind the car
board[ carList[whichCar].yPos ]
[ carList[whichCar].xPos + carList[whichCar].length ] = kEmpty;
// update flag
moveSuccess = true;
}
}
}
}
// return the movement's success
return moveSuccess;
}