# Portable Memory-Mapped File library
libpmmf - [Portable Memory-Mapped File](https://en.wikipedia.org/wiki/Memory-mapped_file) library for C++

## Build:

Build pmmf library for Linux (required [GCC](https://gcc.gnu.org/), [CMake](https://cmake.org/download/), [Make](https://www.gnu.org/software/make/)):

```bash
git clone git@github.com:gbytegear/libpmmf.git
cd ./libpmmf/build
cmake . -G "Unix Makefiles" . -DCMAKE_BUILD_TYPE=Release
make pmmf
```

Result - `libpmmf/build/libpmmf.a`

Build pmmf library for Windows (required [MSys2](https://www.msys2.org/) step 1-5, [MinGW](https://www.msys2.org/) step 6-7, [CMake](https://cmake.org/), [Make](https://packages.msys2.org/package/make)):

```bash
git clone git@github.com:gbytegear/libpmmf.git
cd ./libpmmf/build
cmake . -G "MSYS Makefiles" . -DCMAKE_BUILD_TYPE=Release
make pmmf
```

Result - `libpmmf/build/libpmmf.a`

## Usage:

Link with your project:

```bash
g++ <your_project_source_file> -L<path_to_libpmmf.a> -I<path_to_libpmmf/include> -lpmmf
```

Simple programm example:

```cpp
#include "include/mmf.hxx"
#include <iostream>

#pragma pack(push, 1)

struct Data {
  char cstr[50];
};

#pragma pack(pop)

auto main(int argc, char* argv[]) -> int {

  using namespace pmmf;

  if (argc < 2) {
    std::cerr << "Required 1 file paths!" << std::endl;
    return -1;
  }

  MappedFile mapped_file(argv[1], ProtectionMode::rw, MapFlag::shared);
  if(!mapped_file.isFileOpen()) {
    std::cerr << "Can't open \"" << argv[1] << "\" file" << std::endl;
    return -1;
  }
  std::cout << "File \"" << argv[1] << "\" is open" << std::endl
            << "| File size: " << mapped_file.getFileSize() << " bytes" << std::endl;



  MappedData<Data> second_mapped_array = mapped_file.getMappedData<Data>(sizeof(Data), 2);
  if(!second_mapped_array.isMapped()) {
    std::cerr << "Can't map second area of \"" << argv[1] << "\" file" << std::endl;
    return -1;
  }
  std::cout << "Second area of \"" << argv[1] << "\" file is mapped" << std::endl;



  MappedData<Data> first_mapped_array = mapped_file.getMappedData<Data>(0);
  if(!second_mapped_array.isMapped()) {
    std::cerr << "Can't map first area of \"" << argv[1] << "\" file" << std::endl;
    return -1;
  }
  std::cout << "First area of \"" << argv[1] << "\" file is mapped" << std::endl;



  Data& page_1_data_1 = *first_mapped_array;
  Data& page_2_data_1 = *second_mapped_array;
  Data& page_2_data_2 = second_mapped_array[1];



  new(&page_1_data_1) Data{"Lorem ipsum dolor sit amet, consectetur efficitur"};
  if(!first_mapped_array.flush()) {
    std::cerr << "Can't flush first area of \"" << argv[1] << "\" file" << std::endl;
    return -1;
  }
  std::cout << "First area of \"" << argv[1] << "\" file is flushed" << std::endl
            << "| Recorded data: " << first_mapped_array->cstr << std::endl;



  new(&page_2_data_1) Data{"Lorem ipsum dolor sit amet, consectetur tincidunt"};
  new(&page_2_data_2) Data{"Lorem ipsum dolor sit amet, consectetur porttitor"};
  if(!second_mapped_array.flush()) {
    std::cerr << "Can't flush second area of \"" << argv[1] << "\" file" << std::endl;
    return -1;
  }
  std::cout << "Second area of \"" << argv[1] << "\" file is flushed" << std::endl;


  for(auto& data : second_mapped_array)
    std::cout << "| Recorded data: " << data.cstr << std::endl;



  std::cout << "File size: " << mapped_file.getFileSize() << " bytes" << std::endl;

  return 0;
}
```

