// Copyright (C) 2005-2006 Alain Miniussi <alain.miniussi -at- oca.eu>.

// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

// Message Passing Interface 1.1 -- Section 4. MPI Collectives

/** @file inplace.hpp
 *
 *  This header provides helpers to indicate to MPI collective operation
 *  that a buffer can be use both as an input and output.
 */
#ifndef BOOST_MPI_INPLACE_HPP
#define BOOST_MPI_INPLACE_HPP

#include <boost/mpi/communicator.hpp>
#include <vector>

namespace boost {
namespace mpi {

/**
 *  @brief Wrapper type to explicitly indicate that a input data
 * can be overriden with an output value.
 */
template <typename T> struct inplace_t {
  inplace_t(T &inout) : buffer(inout) {}
  T &buffer;
};

template <typename T> struct inplace_t<T *> {
  inplace_t(T *inout) : buffer(inout) {}
  T *buffer;
};

/**
 *  @brief Wrapp a input data to indicate that it can be overriden
 *  with an ouput value.
 *  @param inout the contributing input value, it will be overriden
 *  with the output value where one is expected. If it is a pointer,
 *  the number of elements will be provided separatly.
 *  @returns The wrapped value or pointer.
 */
template <typename T> inplace_t<T> inplace(T &inout) {
  return inplace_t<T>(inout);
}
/**
 * \overload
 */
template <typename T> inplace_t<T *> inplace(T *inout) {
  return inplace_t<T *>(inout);
}
} // namespace mpi
} // namespace boost

#endif // BOOST_MPI_INPLACE_HPP
