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//
// async_file_copy.cpp
// ~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2023 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)
//
#include <iostream>
#include <boost/asio.hpp>
#if defined(BOOST_ASIO_HAS_FILE)
class file_copier
{
public:
file_copier(boost::asio::io_context& io_context,
const char* from, const char* to)
: from_file_(io_context, from,
boost::asio::stream_file::read_only),
to_file_(io_context, to,
boost::asio::stream_file::write_only
| boost::asio::stream_file::create
| boost::asio::stream_file::truncate)
{
}
void start()
{
do_read();
}
private:
void do_read()
{
from_file_.async_read_some(boost::asio::buffer(data_),
[this](boost::system::error_code error, std::size_t n)
{
if (!error)
{
do_write(n);
}
else if (error != boost::asio::error::eof)
{
std::cerr << "Error copying file: " << error.message() << "\n";
}
});
}
void do_write(std::size_t n)
{
boost::asio::async_write(to_file_, boost::asio::buffer(data_, n),
[this](boost::system::error_code error, std::size_t /*n*/)
{
if (!error)
{
do_read();
}
else
{
std::cerr << "Error copying file: " << error.message() << "\n";
}
});
}
boost::asio::stream_file from_file_;
boost::asio::stream_file to_file_;
char data_[4096];
};
int main(int argc, char* argv[])
{
try
{
if (argc != 3)
{
std::cerr << "Usage: async_file_copy <from> <to>\n";
return 1;
}
boost::asio::io_context io_context;
file_copier copier(io_context, argv[1], argv[2]);
copier.start();
io_context.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
return 1;
}
return 0;
}
#else // defined(BOOST_ASIO_HAS_FILE)
int main() {}
#endif // defined(BOOST_ASIO_HAS_FILE)
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