size_t Board::removeCapturedStones (StoneColor colorToCapture)
{
LOG_FUNCTION(cout, "Board::removeCapturedStones");
size_t captureCount = 0;
// A set of points that we've already examined. This helps prevents some
// bad recursion and keeps a chain from being "found" once for each stone
// in the chain.
//
ConstPointSet alreadyVisited;
for (size_t row = 0; row < m_points.size(); ++row)
{
for (size_t column = 0; column < m_points[row].size(); ++column)
{
const Point & thePoint = m_points.at(row).at(column);
// If the point we are considering has already been visited,
// then Chain's ctor will throw a PointVisitedAlreadyException
// object. We can safely swallow that exception and move on
// to the next point.
//
try
{
Chain currentChain {thePoint, *this, &alreadyVisited};
gLogger.log(LogLevel::kMedium, cout, "Discovered chain"); // " : ", chain);
// If the chain we are looking at is the color we should consider capturing and
// the chain has no liberties, then capture it
//
if (currentChain.color() == colorToCapture && currentChain.libertyCount() == 0)
{
captureCount += currentChain.size();
// For each point in the chain, remove the stone from the board
// at those coordniates
//
currentChain.forEachPoint([this](const Point & point)
{
LOG_BUSY_FUNCTION(cout, "Chain::removeCapturedStones::lambda_doStoneRemoval");
m_points[point.coordinates.row][point.coordinates.column].removeStone();
});
}
}
catch (const Chain::PointVisitedAlreadyException & ex)
{
gLogger.log(LogLevel::kFirehose, cout, "Skipping ", thePoint);
}
}
}
// If we ended up only capturing one stone, the 'Ko' rule might affect
// the next move, so remember that fact!
//
m_koState.first = (captureCount == 1);
return captureCount;
}
