better file structure for better separation

include/file_io/SubFile.hpp

@@ -0,0 +1,32 @@
+#pragma once
+#include "common/defs.hpp"
+#include <cstdint>
+#include <filesystem>
+#include <variant>
+
+class SubFile {
+  protected:
+    FILE *fp = nullptr;
+    uint16_t bitdepth;
+
+  public:
+    // pointer to a read_impl function. pointer will be set to the appropriate read_impl function in the constructor
+    size_t (SubFile::*read_impl)(std::byte *buffer) = nullptr;
+    size_t read_impl_normal(std::byte *buffer);
+    template <typename DataType> size_t  read_impl_flip(std::byte *buffer);
+    template <typename DataType> size_t  read_impl_reorder(std::byte *buffer);
+
+
+    SubFile(std::filesystem::path fname,DetectorType detector, ssize_t rows, ssize_t cols, uint16_t bitdepth);
+
+    size_t get_frame(std::byte *buffer, int frame_number);
+
+    // TODO: define the inlines as variables and assign them in constructor
+    inline size_t bytes_per_frame() { return (bitdepth / 8) * rows * cols; }
+    inline size_t pixels_per_frame() { return rows * cols; }
+    std::filesystem::path fname;
+    ssize_t rows{};
+    ssize_t cols{};
+    ssize_t n_frames{};
+    int sub_file_index_{};
+};