67 lines
1.5 KiB
C++
67 lines
1.5 KiB
C++
//
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// detail/buffer_resize_guard.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2023 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
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#define ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/config.hpp"
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#include "asio/detail/limits.hpp"
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#include "asio/detail/push_options.hpp"
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namespace asio {
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namespace detail {
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// Helper class to manage buffer resizing in an exception safe way.
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template <typename Buffer>
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class buffer_resize_guard
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{
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public:
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// Constructor.
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buffer_resize_guard(Buffer& buffer)
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: buffer_(buffer),
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old_size_(buffer.size())
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{
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}
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// Destructor rolls back the buffer resize unless commit was called.
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~buffer_resize_guard()
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{
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if (old_size_ != (std::numeric_limits<size_t>::max)())
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{
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buffer_.resize(old_size_);
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}
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}
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// Commit the resize transaction.
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void commit()
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{
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old_size_ = (std::numeric_limits<size_t>::max)();
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}
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private:
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// The buffer being managed.
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Buffer& buffer_;
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// The size of the buffer at the time the guard was constructed.
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size_t old_size_;
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};
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} // namespace detail
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#endif // ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
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