PackedBuffer.h

PackedBuffer.h

template <typename T, bool (*remove_predicate)(const T&)>
class PackedBuffer
{
public:

	PackedBuffer(size_t size)
		: size_(0)
		, buffer_(size)
	{}
	
	size_t size() const { return size_; }
	void clear() { size_ = 0; }

	T& add()
	{
		T& o = buffer_[size_];
		size_++;
		
		if (size_ > buffer_.size())
			size_ = buffer_.size();
		
		return o;
	}
	
	void add(const T& v)
	{
		T& o = add();
		o = v;
	}

	void pack()
	{
		for (int i = 0; i < size_; i++)
		{
			const T& o = buffer_[i];
			if (!remove_predicate(o))
			{
				remove_element(i);
				i--;
			}
		}
	}

	T& operator[](size_t index) { return buffer_[index]; }
	const T& operator[](size_t index) const { return buffer_[index]; }

private:

	size_t size_;
	std::vector<T> buffer_;
	
	void remove_element(size_t index)
	{
		std::swap(buffer_[index], buffer_[size_ - 1]);
		size_--;
	}
};