Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2025 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
       3             : 
       4             : // This library is free software; you can redistribute it and/or
       5             : // modify it under the terms of the GNU Lesser General Public
       6             : // License as published by the Free Software Foundation; either
       7             : // version 2.1 of the License, or (at your option) any later version.
       8             : 
       9             : // This library is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             : // Lesser General Public License for more details.
      13             : 
      14             : // You should have received a copy of the GNU Lesser General Public
      15             : // License along with this library; if not, write to the Free Software
      16             : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      17             : 
      18             : 
      19             : 
      20             : #ifndef LIBMESH_NULL_OUTPUT_ITERATOR_H
      21             : #define LIBMESH_NULL_OUTPUT_ITERATOR_H
      22             : 
      23             : // Local includes
      24             : 
      25             : // C++ includes
      26             : #include <iterator>
      27             : 
      28             : namespace libMesh
      29             : {
      30             : 
      31             : /**
      32             :  * A do-nothing class for templated methods that expect output
      33             :  * iterator arguments.
      34             :  *
      35             :  * \author Roy Stogner
      36             :  * \date 2012
      37             :  * \brief A do-nothing output iterator implementation.
      38             :  */
      39             : template <typename T>
      40             : struct null_output_iterator
      41             : {
      42             :   using iterator_category = std::output_iterator_tag;
      43             :   using value_type = T;
      44             :   using difference_type = std::ptrdiff_t;
      45             :   using pointer = T*;
      46             :   using reference = T&;
      47             : 
      48             :   template <typename T2>
      49      101163 :   void operator=(const T2&) {}
      50             : 
      51             :   null_output_iterator & operator++()
      52             :   {
      53             :     return *this;
      54             :   }
      55             : 
      56      101163 :   null_output_iterator operator++(int)
      57             :   {
      58      101163 :     return null_output_iterator(*this);
      59             :   }
      60             : 
      61             :   // We don't return a reference-to-T here because we don't want to
      62             :   // construct one or have any of its methods called.
      63      101163 :   null_output_iterator & operator*() { return *this; }
      64             : };
      65             : 
      66             : } // namespace libMesh
      67             : 
      68             : 
      69             : #endif // LIBMESH_NULL_OUTPUT_ITERATOR_H