New upstream version 8.1.0

fsck/source/database/Select.h

@@ -0,0 +1,74 @@
+#ifndef SELECT_H_
+#define SELECT_H_
+
+#include <boost/utility/result_of.hpp>
+
+template<typename Source, typename Fn>
+class Select
+{
+   public:
+      typedef typename boost::result_of<Fn(typename Source::ElementType&)>::type ElementType;
+      typedef typename Source::MarkerType MarkerType;
+
+   public:
+      Select(Source source, Fn fn)
+         : source(source), fn(fn)
+      {
+      }
+
+      bool step()
+      {
+         if(!this->source.step() )
+            return false;
+
+         this->current = this->fn(*this->source.get() );
+         return true;
+      }
+
+      ElementType* get()
+      {
+         return &current;
+      }
+
+      MarkerType mark() const
+      {
+         return this->source.mark();
+      }
+
+      void restore(MarkerType mark)
+      {
+         this->source.restore(mark);
+         this->current = this->fn(*this->source.get() );
+      }
+
+   private:
+      Source source;
+      Fn fn;
+      ElementType current;
+};
+
+
+namespace db {
+
+template<typename Pred>
+struct SelectOp
+{
+   Pred pred;
+
+   template<typename Source>
+   friend Select<Source, Pred> operator|(Source source, const SelectOp& op)
+   {
+      return Select<Source, Pred>(source, op.pred);
+   }
+};
+
+template<typename Pred>
+inline SelectOp<Pred> select(Pred pred)
+{
+   SelectOp<Pred> result = {pred};
+   return result;
+}
+
+}
+
+#endif