Headers moved to subdir stg

[stg.git] / include / stg / resetable.h

diff --git a/include/stg/resetable.h b/include/stg/resetable.h
new file mode 100644 (file)
index 0000000..d31bffd
--- /dev/null
+++ b/include/stg/resetable.h
@@ -0,0 +1,98 @@
+ /*
+ $Revision: 1.9 $
+ $Date: 2010/03/11 14:42:04 $
+ $Author: faust $
+ */
+
+/*
+ * Copyright (c) 2001 by Peter Simons <simons@cryp.to>.
+ * All rights reserved.
+ */
+
+#ifndef RESETABLE_VARIABLE_H
+#define RESETABLE_VARIABLE_H
+
+// This is a wrapper class about variables where you want to keep
+// track of whether it has been assigened yet or not.
+
+#include <iostream>
+
+template <typename varT>
+class RESETABLE
+{
+    template <typename varT1>
+    friend std::ostream & operator<<(std::ostream & o, RESETABLE<varT1> v);
+public:
+    typedef varT value_type;
+
+    //-------------------------------------------------------------------------
+    RESETABLE()
+        : value(),
+          is_set(false)
+    {
+    }
+    //-------------------------------------------------------------------------
+    RESETABLE<value_type>(const RESETABLE<value_type> & rvalue)
+        : value(rvalue.value),
+          is_set(rvalue.is_set)
+    {
+    }
+    //-------------------------------------------------------------------------
+    RESETABLE(const value_type& val)
+        : value(val),
+          is_set(true)
+    {
+    }
+    //-------------------------------------------------------------------------
+    RESETABLE<value_type> & operator=(const RESETABLE<value_type> & rvalue)
+    {
+        value = rvalue.value;
+        is_set = rvalue.is_set;
+        return *this;
+    }
+    //-------------------------------------------------------------------------
+    RESETABLE<value_type> & operator= (const value_type& rhs)
+    {
+        value = rhs;
+        is_set = true;
+        return *this;
+    }
+    //-------------------------------------------------------------------------
+    const value_type& const_data() const throw()
+    {
+        return value;
+    }
+    //-------------------------------------------------------------------------
+    value_type& data() throw()
+    {
+        return value;
+    }
+    //-------------------------------------------------------------------------
+    operator const value_type&() const throw()
+    {
+        return value;
+    }
+    //-------------------------------------------------------------------------
+    bool res_empty() const throw()
+    {
+        return !is_set;
+    }
+    //-------------------------------------------------------------------------
+    void reset() throw()
+    {
+        is_set = false;
+    }
+    //-------------------------------------------------------------------------
+protected:
+    value_type  value;
+    bool        is_set;
+};
+//-----------------------------------------------------------------------------
+template <typename varT>
+std::ostream & operator<<(std::ostream & o, RESETABLE<varT> v)
+{
+    return o << v.value;
+}
+//-------------------------------------------------------------------------
+#endif // RESETABLE_VARIABLE_H
+