eonix/include/types/bitmap.hpp

#pragma once

#include <cstddef>
#include <functional>

namespace types {

class bitmap {
   public:
    using deleter_type = std::function<void(unsigned char*, std::size_t)>;

   private:
    deleter_type m_del;
    std::size_t m_size;
    unsigned char* m_bm;

    static constexpr std::size_t SZ = sizeof(unsigned char) * 8;

   public:
    constexpr bitmap(const deleter_type& del, unsigned char* bm,
                     std::size_t size)
        : m_del(del), m_size(size), m_bm(bm) {}
    constexpr bitmap(deleter_type&& del, unsigned char* bm, std::size_t size)
        : m_del(std::move(del)), m_size(size), m_bm(bm) {}

    explicit constexpr bitmap(std::size_t size)
        : m_del{[](unsigned char* bm, std::size_t) { delete[] bm; }}
        , m_size{(size / SZ) + ((size % SZ) ? 1 : 0)}
        , m_bm{new unsigned char[m_size]{}} {}

    bitmap(const bitmap&) = delete;

    constexpr ~bitmap() { m_del(m_bm, m_size); }

    constexpr bool test(std::size_t n) const {
        return (m_bm[n / SZ] & (1 << (n % SZ))) != 0;
    }

    constexpr void set(std::size_t n) { m_bm[n / SZ] |= (1 << (n % SZ)); }

    constexpr void clear(std::size_t n) { m_bm[n / SZ] &= (~(1 << (n % SZ))); }

    constexpr std::size_t size() const noexcept { return m_size; }
};

} // namespace types