Handout

debug/nullstream.h

@@ -0,0 +1,45 @@
+/*! \file
+ *  \brief \ref NullStream is a stream discarding everything
+ */
+
+#pragma once
+#include "../object/outputstream.h"
+#include "../types.h"
+
+/*! \brief Ignore all data passed by the stream operator
+ *  \ingroup io
+ *
+ * Can be used instead of the \ref OutputStream if (for debugging reasons) all
+ * output should be ignored, e.g. for \ref DBG_VERBOSE
+ *
+ * By using template programming, a single generic methods is sufficient
+ * (which simply discard everything).
+ */
+class NullStream {
+  /*! \brief Check if type is supported by output stream
+   */
+  template <typename T>
+  auto check(T v, OutputStream* p = nullptr) -> decltype(*p << v, void()) {}
+
+ public:
+  /*! \brief Empty default constructor
+   */
+  NullStream() {}
+
+  /*! \brief Generic stream operator for any data type
+   *
+   * Uses template meta programming for a generic & short solution
+   *
+   * \tparam T Type of data to ignore
+   * \param value data to be ignore
+   * \return Reference to the \ref NullStream object allowing concatenation of
+   * operators
+   */
+  template <typename T>
+  NullStream& operator<<(T value) {
+    check(value);
+    return *this;
+  }
+};
+
+extern NullStream nullstream;