indexed_collector.hpp

#pragma once
 
#include <vector>
 
namespace wmtk::threading {
 
template <typename T>
class indexed_collector
{
    std::vector<T> m_slots;
    std::vector<char> m_filled;
 
public:
    explicit indexed_collector(std::size_t n)
        : m_slots(n)
        , m_filled(n, 0)
    {}
 
    void set(std::size_t i, const T& v)
    {
        m_slots[i] = v;
        m_filled[i] = 1;
    }
 
    std::vector<T> compact() const
    {
        std::vector<T> out;
        out.reserve(m_slots.size());
        for (std::size_t i = 0; i < m_slots.size(); ++i) {
            if (m_filled[i]) {
                out.push_back(m_slots[i]);
            }
        }
        return out;
    }
};
 
} // namespace wmtk::threading