ExtSaveData work

include/io_file.hpp

@@ -24,6 +24,9 @@ class IOFile {
 public:
     IOFile() {}
     IOFile(FILE* handle) : handle(handle) {}
+    IOFile(const std::filesystem::path& path, const char* permissions = "rb") {
+        open(path, permissions);
+    }
 
     bool isOpen() {
         return handle != nullptr;
@@ -86,6 +89,10 @@ public:
         return seek(0, SEEK_SET);
     }
 
+    FILE* getHandle() {
+        return handle;
+    }
+
     static void setAppDataDir(const char* dir) {
         if (!dir) Helpers::panic("Failed to set app data directory");
         appData = std::filesystem::path(dir);