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Diffstat (limited to 'lib/asio/detail/buffer_resize_guard.hpp')
-rw-r--r-- | lib/asio/detail/buffer_resize_guard.hpp | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/lib/asio/detail/buffer_resize_guard.hpp b/lib/asio/detail/buffer_resize_guard.hpp new file mode 100644 index 0000000..58ebc4c --- /dev/null +++ b/lib/asio/detail/buffer_resize_guard.hpp @@ -0,0 +1,66 @@ +// +// detail/buffer_resize_guard.hpp +// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2018 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 ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP +#define ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP + +#if defined(_MSC_VER) && (_MSC_VER >= 1200) +# pragma once +#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) + +#include "asio/detail/config.hpp" +#include "asio/detail/limits.hpp" + +#include "asio/detail/push_options.hpp" + +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)()) + { + buffer_.resize(old_size_); + } + } + + // Commit the resize transaction. + void commit() + { + old_size_ = (std::numeric_limits<size_t>::max)(); + } + +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 + +#include "asio/detail/pop_options.hpp" + +#endif // ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP |