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_UTILITY_SWAP_HPP 10 #define BOOST_UTILITY_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 <algorithm> //for std::swap 25 #include <cstddef> //for std::size_t 26 27 namespace boost_swap_impl 28 { 29 template<class T> 30 void swap_impl(T& left, T& right) 31 { 32 using namespace std;//use std::swap if argument dependent lookup fails 33 swap(left,right); 34 } 35 36 template<class T, std::size_t N> 37 void swap_impl(T (& left)[N], T (& right)[N]) 38 { 39 for (std::size_t i = 0; i < N; ++i) 40 { 41 ::boost_swap_impl::swap_impl(left[i], right[i]); 42 } 43 } 44 } 45 46 namespace boost 47 { 48 template<class T1, class T2> 49 void swap(T1& left, T2& right) 50 { 51 ::boost_swap_impl::swap_impl(left, right); 52 } 53 } 54 55 #endif 56
