diff -r 06a0015b6a5c -r 32ad0523b309 src/Structures.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Structures.h	Tue Jul 24 23:53:34 2012 -0700
@@ -0,0 +1,60 @@
+/* vim: set ts=4 sw=4 tw=99 et
+ *
+ * Copyright (C) 2012 David Anderson
+ *
+ * This file is part of JITCraft.
+ *
+ * JITCraft is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ * 
+ * Foobar is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * JITCraft. If not, see http://www.gnu.org/licenses/.
+ */
+#ifndef _include_jc_structure_h_
+#define _include_jc_structure_h_
+
+#include "Objects.h"
+#include "Handles.h"
+#include "Vector.h"
+
+namespace ke {
+
+class Type;
+class String;
+class FixedArray;
+
+// When describing composite structures, the GC must be able to trace interior
+// references to Objects. To make this possible, maps that describe composite
+// structures must provide a list of offsets into their objects that are
+// traceable. StructureBufferBuilder assists with this.
+class StructureBufferBuilder
+{
+  public:
+    StructureBufferBuilder();
+
+    bool add(Handle<Type> type, unsigned *offset);
+
+    unsigned structureSize() const {
+        return size_;
+    }
+    unsigned traceableOffsetCount() const {
+        return offsets_.length();
+    }
+    const unsigned *offsets() {
+        return offsets_.buffer();
+    }
+
+  private:
+    Vector<unsigned> offsets_;
+    unsigned size_;
+};
+
+}
+
+#endif // _include_jc_structure_h_