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//
// 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
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