chore: rearrange library/export structure

thermion_dart/lib/src/utils/dart_resources.dart

@@ -0,0 +1,30 @@
+import 'dart:ffi';
+import 'dart:io';
+
+import 'package:ffi/ffi.dart';
+
+import '../viewer/src/ffi/src/thermion_dart.g.dart';
+
+class DartResourceLoader {
+  static final _assets = <int, Pointer>{};
+  static void loadResource(Pointer<Char> uri, Pointer<ResourceBuffer> out) {
+    try {
+      var data = File(uri.cast<Utf8>().toDartString().replaceAll("file://", ""))
+          .readAsBytesSync();
+      var ptr = calloc<Uint8>(data.lengthInBytes);
+      ptr.asTypedList(data.lengthInBytes).setRange(0, data.lengthInBytes, data);
+
+      out.ref.data = ptr.cast<Void>();
+      out.ref.size = data.lengthInBytes;
+      out.ref.id = _assets.length;
+      _assets[out.ref.id] = ptr;
+    } catch (err) {
+      print(err);
+      out.ref.size = -1;
+    }
+  }
+
+  static void freeResource(ResourceBuffer rb) {
+    calloc.free(_assets[rb.id]!);
+  }
+}