added utf8 support

lib/src/ffi/cstring.dart

@@ -1,24 +1,36 @@
 import "dart:ffi";
+import "dart:typed_data";
+import "package:utf/src/utf8.dart";
+import "package:utf/src/utf16.dart";
 
+// TODO check if revamp structs are relevant (https://github.com/dart-lang/sdk/issues/37229)
 // wrapper for a null-terminated array of characters in memory ("c-style string")
 class CString {
     Pointer<Uint8> _ptr;
 
-    CString(String dartStr) {                                   // if this constructor is used, ".free" needs to be called on this instance
-        _ptr = allocate(count: dartStr.length + 1);
-        for(int i = 0; i < dartStr.length; ++i)
-            _ptr.elementAt(i).store(dartStr.codeUnitAt(i));
-        _ptr.elementAt(dartStr.length).store(0);
+    // if this constructor is used, ".free" needs to be called on this instance
+    CString(String dartStr) {
+        final ints = encodeUtf8(dartStr);
+        _ptr = Pointer<Uint8>.allocate(count: ints.length + 1);
+        for(int i = 0; i < ints.length; ++i) {
+            _ptr.elementAt(i).store(ints.elementAt(i));
+        }
+        _ptr.elementAt(ints.length).store(0);
     }
 
     CString.fromPtr(this._ptr);
 
     String get val {
-        String ret = "", c;
-        int i = 0;
-        while((c = String.fromCharCode(_ptr.elementAt(i++).load<int>())).codeUnitAt(0) != 0)          // TODO: unicode support
-            ret += c;
-        return ret;
+        List<int> utf8CodePoints = new List<int>();
+
+        int element;
+
+        for (int i=0; element != 0; i++) {
+	    element = _ptr.elementAt(i).load<int>();
+	    utf8CodePoints.add(element);
+        }
+
+        return decodeUtf8(utf8CodePoints);
     }
 
     String toString() => val;

pubspec.yaml

@@ -1,8 +1,9 @@
 name: objectbox
-version: 0.0.1
+version: 0.0.2
 description: >-
   ObjectBox binding for Dart.
 environment:
   sdk: '>=2.2.2 <3.0.0'
 dependencies:
   flat_buffers: ^1.11.0
+  utf: ^0.9.0

test/test.dart

@@ -1,4 +1,5 @@
 import "../lib/objectbox.dart";
+import "package:utf/src/utf8.dart";
 
 @Entity(id: 1, uid: 1)
 class Note {
@@ -17,11 +18,16 @@ class Note {
 main() {
     var store = Store([Note]);
     var box = Box<Note>(store);
+    insertNote(box, decodeUtf8([104, 101, 108, 108, 111, 32, 119, 111, 114, 108, 100]));
+    insertNote(box, decodeUtf8([228, 189, 160, 229, 165, 189, 228, 184, 150, 231, 149, 140, 33]));
+    insertNote(box, decodeUtf8([65, 104, 111, 106, 32, 115, 118, 196, 155, 116, 101, 33]));
+    store.close();
+}
 
-    var note = Note.construct("Hello");
+insertNote(Box<Note> box, String str) {
+    var note = Note.construct(str);
     box.put(note);
+
     print("new note got id ${note.id}");
     print("refetched note: ${box.getById(note.id)}");
-
-    store.close();
 }