io_fileview.h

#ifndef SOURCEMETA_CORE_IO_FILEVIEW_H_
#define SOURCEMETA_CORE_IO_FILEVIEW_H_
 
#ifndef SOURCEMETA_CORE_IO_EXPORT
#include <sourcemeta/core/io_export.h>
#endif
 
#include <cassert>    // assert
#include <cstddef>    // std::size_t
#include <cstdint>    // std::uint8_t
#include <filesystem> // std::filesystem::path
 
namespace sourcemeta::core {

class SOURCEMETA_CORE_IO_EXPORT FileView {
public:
  FileView(const std::filesystem::path &path);
  ~FileView();
 
  // Disable copying and moving
  FileView(const FileView &) = delete;
  FileView(FileView &&) = delete;
  auto operator=(const FileView &) -> FileView & = delete;
  auto operator=(FileView &&) -> FileView & = delete;

  [[nodiscard]] auto size() const noexcept -> std::size_t;

  template <typename T>
  [[nodiscard]] auto as(const std::size_t offset = 0) const noexcept
      -> const T * {
    assert(offset + sizeof(T) <= this->size_);
    // NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast)
    return reinterpret_cast<const T *>(this->data_ + offset);
  }
 
private:
  const std::uint8_t *data_{nullptr};
  std::size_t size_{0};
#if defined(_WIN32)
  void *file_handle_{nullptr};
  void *mapping_handle_{nullptr};
#else
  int file_descriptor_{-1};
#endif
};
 
} // namespace sourcemeta::core
 
#endif