// | |
// detail/buffer_resize_guard.hpp | |
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
// | |
// Copyright (c) 2003-2011 Christopher M. Kohlhoff (chris at kohlhoff dot com) | |
// | |
// Distributed under 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) | |
// | |
#ifndef BOOST_ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP | |
#define BOOST_ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP | |
#if defined(_MSC_VER) && (_MSC_VER >= 1200) | |
# pragma once | |
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) | |
#include <boost/asio/detail/config.hpp> | |
#include <boost/limits.hpp> | |
#include <boost/asio/detail/push_options.hpp> | |
namespace boost { | |
namespace asio { | |
namespace detail { | |
// Helper class to manage buffer resizing in an exception safe way. | |
template <typename Buffer> | |
class buffer_resize_guard | |
{ | |
public: | |
// Constructor. | |
buffer_resize_guard(Buffer& buffer) | |
: buffer_(buffer), | |
old_size_(buffer.size()) | |
{ | |
} | |
// Destructor rolls back the buffer resize unless commit was called. | |
~buffer_resize_guard() | |
{ | |
if (old_size_ | |
!= std::numeric_limits<size_t>::max BOOST_PREVENT_MACRO_SUBSTITUTION()) | |
{ | |
buffer_.resize(old_size_); | |
} | |
} | |
// Commit the resize transaction. | |
void commit() | |
{ | |
old_size_ | |
= std::numeric_limits<size_t>::max BOOST_PREVENT_MACRO_SUBSTITUTION(); | |
} | |
private: | |
// The buffer being managed. | |
Buffer& buffer_; | |
// The size of the buffer at the time the guard was constructed. | |
size_t old_size_; | |
}; | |
} // namespace detail | |
} // namespace asio | |
} // namespace boost | |
#include <boost/asio/detail/pop_options.hpp> | |
#endif // BOOST_ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP |