--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Framework/Toolbox/DownloadStack.h	Fri Oct 14 15:34:11 2016 +0200
@@ -0,0 +1,87 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ *
+ * This program 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.
+ *
+ * In addition, as a special exception, the copyright holders of this
+ * program give permission to link the code of its release with the
+ * OpenSSL project's "OpenSSL" library (or with modified versions of it
+ * that use the same license as the "OpenSSL" library), and distribute
+ * the linked executables. You must obey the GNU General Public License
+ * in all respects for all of the code used other than "OpenSSL". If you
+ * modify file(s) with this exception, you may extend this exception to
+ * your version of the file(s), but you are not obligated to do so. If
+ * you do not wish to do so, delete this exception statement from your
+ * version. If you delete this exception statement from all source files
+ * in the program, then also delete it here.
+ * 
+ * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#pragma once
+
+#include <vector>
+#include <boost/noncopyable.hpp>
+#include <boost/thread/mutex.hpp>
+
+namespace OrthancStone
+{
+  class DownloadStack : public boost::noncopyable
+  {
+  private:
+    static const int NIL = -1;
+
+    // This is a doubly-linked list
+    struct Node
+    {
+      int   next_;
+      int   prev_;
+      bool  dequeued_;
+    };
+
+    boost::mutex        mutex_;
+    std::vector<Node>   nodes_;
+    int                 firstNode_;
+
+    bool CheckInvariants() const;
+
+    void SetTopNodeInternal(unsigned int value);  
+
+  public:
+    DownloadStack(unsigned int size);
+
+    ~DownloadStack();
+
+    bool Pop(unsigned int& value);
+
+    class Writer : public boost::noncopyable
+    {
+    private:
+      DownloadStack&              that_;
+      boost::mutex::scoped_lock   lock_;
+      
+    public:
+      Writer(DownloadStack& that) :
+        that_(that),
+        lock_(that.mutex_)
+      {
+      }
+      
+      void SetTopNode(unsigned int value);  
+
+      void SetTopNodePermissive(int value);
+    };
+  };
+}