forked from boostorg/beast
Vinnie Falco
a7ef4f53dc
This eliminates beast::write output for dynamic buffers and replaces it with the function ostream() that wraps a caller provided dynamic buffer and returns the result as a std::ostream derived object. Callers may now produce formatted output into any object meeting the requirements of DynamicBuffer using operator<< and the standard stream modifiers such as std::endl. This new technique is more efficient, as implementations of operator<< can now write directly into the output using std::ostream::write and std::ostream::put. Example of use: beast::streambuf sb; beast::ostream(sb) << "Hello, world!" << std::endl;
67 lines
2.0 KiB
C++
67 lines
2.0 KiB
C++
//
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// Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail 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 BEAST_WRITE_OSTREAM_HPP
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#define BEAST_WRITE_OSTREAM_HPP
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#include <beast/config.hpp>
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#include <beast/core/buffer_concepts.hpp>
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#include <beast/core/detail/ostream.hpp>
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#include <type_traits>
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#include <streambuf>
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#include <utility>
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namespace beast {
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/** Return an output stream that formats values into a @b DynamicBuffer.
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This function wraps the caller provided @b DynamicBuffer into
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a `std::ostream` derived class, to allow `operator<<` stream style
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formatting operations.
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@par Example
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@code
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ostream(buffer) << "Hello, world!" << std::endl;
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@endcode
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@note Calling members of the underlying buffer before the output
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stream is destroyed results in undefined behavior.
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@param buffer An object meeting the requirements of @b DynamicBuffer
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into which the formatted output will be placed.
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@return An object derived from `std::ostream` which directs output
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into the specified dynamic buffer. Ownership of the dynamic buffer
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is not transferred. The caller is responsible for ensuring the
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dynamic buffer is not destroyed for the lifetime of the output
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stream.
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*/
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template<class DynamicBuffer>
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#if BEAST_DOXYGEN
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implementation_defined
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#else
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detail::ostream_helper<
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DynamicBuffer, char, std::char_traits<char>,
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std::is_move_constructible<
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detail::ostream_buffer<DynamicBuffer,
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char, std::char_traits<char>>>::value>
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#endif
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ostream(DynamicBuffer& buffer)
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{
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static_assert(is_DynamicBuffer<DynamicBuffer>::value,
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"DynamicBuffer requirements not met");
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return detail::ostream_helper<
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DynamicBuffer, char, std::char_traits<char>,
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std::is_move_constructible<
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detail::ostream_buffer<DynamicBuffer,
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char, std::char_traits<char>>>::value>{buffer};
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}
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} // beast
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#endif
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