#pragma once

#include <cstddef>
#include <cstdint>


namespace ipc {
namespace shm {

using id_t = void*;

enum : unsigned {
    create = 0x01,
    open   = 0x02
};

extern id_t         acquire(char const * name, std::size_t size, unsigned mode = create | open);
extern void *       get_mem(id_t id, std::size_t * size);
extern std::int32_t release(id_t id);
extern void         remove (id_t id);
extern void         remove (char const * name);

extern std::int32_t get_ref(id_t id);
extern void sub_ref(id_t id);

class handle {
public:
    handle();
    handle(char const * name, std::size_t size, unsigned mode = create | open);
    handle(handle&& rhs);

    ~handle();

    void swap(handle& rhs);
    handle& operator=(handle rhs);

    bool         valid() const noexcept;
    std::size_t  size () const noexcept;
    char const * name () const noexcept;

    std::int32_t ref() const noexcept;
    void sub_ref() noexcept;

    bool acquire(char const * name, std::size_t size, unsigned mode = create | open);
    std::int32_t release();

    void* get() const;

    void attach(id_t);
    id_t detach();

private:
    class handle_;
    handle_* p_;
};

} // namespace shm
} // namespace ipc