ceph/src/boost/boost/core/swap.hpp

   1 // Copyright (C) 2007, 2008 Steven Watanabe, Joseph Gauterin, Niels Dekker
   2 //
   3 // Distributed under the Boost Software License, Version 1.0. (See
   4 // accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6 // For more information, see http://www.boost.org
   7
   8
   9 #ifndef BOOST_CORE_SWAP_HPP
  10 #define BOOST_CORE_SWAP_HPP
  11
  12 // Note: the implementation of this utility contains various workarounds:
  13 // - swap_impl is put outside the boost namespace, to avoid infinite
  14 // recursion (causing stack overflow) when swapping objects of a primitive
  15 // type.
  16 // - swap_impl has a using-directive, rather than a using-declaration,
  17 // because some compilers (including MSVC 7.1, Borland 5.9.3, and
  18 // Intel 8.1) don't do argument-dependent lookup when it has a
  19 // using-declaration instead.
  20 // - boost::swap has two template arguments, instead of one, to
  21 // avoid ambiguity when swapping objects of a Boost type that does
  22 // not have its own boost::swap overload.
  23
  24 #include <boost/core/enable_if.hpp>
  25 #include <boost/config.hpp>
  26 #include <utility> //for std::swap (C++11)
  27 #include <algorithm> //for std::swap (C++98)
  28 #include <cstddef> //for std::size_t
  29
  30 namespace boost_swap_impl
  31 {
  32   // we can't use type_traits here
  33
  34   template<class T> struct is_const { enum _vt { value = 0 }; };
  35   template<class T> struct is_const<T const> { enum _vt { value = 1 }; };
  36
  37   template<class T>
  38   BOOST_GPU_ENABLED
  39   void swap_impl(T& left, T& right)
  40   {
  41     using namespace std;//use std::swap if argument dependent lookup fails
  42     swap(left,right);
  43   }
  44
  45   template<class T, std::size_t N>
  46   BOOST_GPU_ENABLED
  47   void swap_impl(T (& left)[N], T (& right)[N])
  48   {
  49     for (std::size_t i = 0; i < N; ++i)
  50     {
  51       ::boost_swap_impl::swap_impl(left[i], right[i]);
  52     }
  53   }
  54 }
  55
  56 namespace boost
  57 {
  58   template<class T1, class T2>
  59   BOOST_GPU_ENABLED
  60   typename enable_if_c< !boost_swap_impl::is_const<T1>::value && !boost_swap_impl::is_const<T2>::value >::type
  61   swap(T1& left, T2& right)
  62   {
  63     ::boost_swap_impl::swap_impl(left, right);
  64   }
  65 }
  66
  67 #endif