59 lines
1.6 KiB
C++
Executable file
59 lines
1.6 KiB
C++
Executable file
#pragma once
|
|
#include <fc/interprocess/file_mapping.hpp>
|
|
#include <memory>
|
|
|
|
namespace fc
|
|
{
|
|
class path;
|
|
namespace detail
|
|
{
|
|
/**
|
|
* Base class used to hide common implementation details.
|
|
*/
|
|
class mmap_struct_base
|
|
{
|
|
public:
|
|
size_t size()const;
|
|
void flush();
|
|
|
|
protected:
|
|
void open( const fc::path& file, size_t s, bool create );
|
|
std::unique_ptr<fc::file_mapping> _file_mapping;
|
|
std::unique_ptr<fc::mapped_region> _mapped_region;
|
|
};
|
|
};
|
|
|
|
/**
|
|
* @class mmap_struct
|
|
* @brief A struct that has been mapped from a file.
|
|
*
|
|
* @note T must be POD
|
|
*/
|
|
template<typename T>
|
|
class mmap_struct : public detail::mmap_struct_base
|
|
{
|
|
public:
|
|
mmap_struct():_mapped_struct(nullptr){}
|
|
/**
|
|
* Create the file if it does not exist or is of the wrong size if create is true, then maps
|
|
* the file to memory.
|
|
*
|
|
* @throw an exception if the file does not exist or is the wrong size and create is false
|
|
*/
|
|
void open( const fc::path& file, bool create = false )
|
|
{
|
|
detail::mmap_struct_base::open( file, sizeof(T), create );
|
|
_mapped_struct = (T*)_mapped_region->get_address();
|
|
}
|
|
|
|
T* operator->() { return _mapped_struct; }
|
|
const T* operator->()const { return _mapped_struct; }
|
|
|
|
T& operator*() { return *_mapped_struct; }
|
|
const T& operator*()const { return *_mapped_struct; }
|
|
|
|
private:
|
|
T* _mapped_struct;
|
|
};
|
|
|
|
}
|