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Diffstat (limited to 'boost/beast/core/buffer_traits.hpp')
| -rw-r--r-- | boost/beast/core/buffer_traits.hpp | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/boost/beast/core/buffer_traits.hpp b/boost/beast/core/buffer_traits.hpp new file mode 100644 index 0000000000..f7b9adae7a --- /dev/null +++ b/boost/beast/core/buffer_traits.hpp @@ -0,0 +1,164 @@ +// +// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail 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) +// +// Official repository: https://github.com/boostorg/beast +// + +#ifndef BOOST_BEAST_BUFFER_TRAITS_HPP +#define BOOST_BEAST_BUFFER_TRAITS_HPP + +#include <boost/beast/core/detail/config.hpp> +#include <boost/beast/core/detail/buffer_traits.hpp> +#include <boost/beast/core/detail/static_const.hpp> +#include <boost/asio/buffer.hpp> +#include <boost/config/workaround.hpp> +#include <boost/mp11/function.hpp> +#include <type_traits> + +namespace boost { +namespace beast { + +/** Determine if a list of types satisfy the <em>ConstBufferSequence</em> requirements. + + This metafunction is used to determine if all of the specified types + meet the requirements for constant buffer sequences. This type alias + will be `std::true_type` if each specified type meets the requirements, + otherwise, this type alias will be `std::false_type`. + + @tparam BufferSequence A list of zero or more types to check. If this + list is empty, the resulting type alias will be `std::true_type`. +*/ +template<class... BufferSequence> +#if BOOST_BEAST_DOXYGEN +using is_const_buffer_sequence = __see_below__; +#else +using is_const_buffer_sequence = mp11::mp_all< + net::is_const_buffer_sequence< + typename std::decay<BufferSequence>::type>...>; +#endif + +/** Determine if a list of types satisfy the <em>MutableBufferSequence</em> requirements. + + This metafunction is used to determine if all of the specified types + meet the requirements for mutable buffer sequences. This type alias + will be `std::true_type` if each specified type meets the requirements, + otherwise, this type alias will be `std::false_type`. + + @tparam BufferSequence A list of zero or more types to check. If this + list is empty, the resulting type alias will be `std::true_type`. +*/ +template<class... BufferSequence> +#if BOOST_BEAST_DOXYGEN +using is_mutable_buffer_sequence = __see_below__; +#else +using is_mutable_buffer_sequence = mp11::mp_all< + net::is_mutable_buffer_sequence< + typename std::decay<BufferSequence>::type>...>; +#endif + +/** Type alias for the underlying buffer type of a list of buffer sequence types. + + This metafunction is used to determine the underlying buffer type for + a list of buffer sequence. The equivalent type of the alias will vary + depending on the template type argument: + + @li If every type in the list is a <em>MutableBufferSequence</em>, + the resulting type alias will be `net::mutable_buffer`, otherwise + + @li The resulting type alias will be `net::const_buffer`. + + @par Example + The following code returns the first buffer in a buffer sequence, + or generates a compilation error if the argument is not a buffer + sequence: + @code + template <class BufferSequence> + buffers_type <BufferSequence> + buffers_front (BufferSequence const& buffers) + { + static_assert( + net::is_const_buffer_sequence<BufferSequence>::value, + "BufferSequence type requirements not met"); + auto const first = net::buffer_sequence_begin (buffers); + if (first == net::buffer_sequence_end (buffers)) + return {}; + return *first; + } + @endcode + + @tparam BufferSequence A list of zero or more types to check. If this + list is empty, the resulting type alias will be `net::mutable_buffer`. +*/ +template<class... BufferSequence> +#if BOOST_BEAST_DOXYGEN +using buffers_type = __see_below__; +#else +using buffers_type = typename std::conditional< + is_mutable_buffer_sequence<BufferSequence...>::value, + net::mutable_buffer, net::const_buffer>::type; +#endif + +/** Type alias for the iterator type of a buffer sequence type. + + This metafunction is used to determine the type of iterator + used by a particular buffer sequence. + + @tparam T The buffer sequence type to use. The resulting + type alias will be equal to the iterator type used by + the buffer sequence. +*/ +template <class BufferSequence> +#if BOOST_BEAST_DOXYGEN +using buffers_iterator_type = __see_below__; +#elif BOOST_WORKAROUND(BOOST_MSVC, < 1910) +using buffers_iterator_type = typename + detail::buffers_iterator_type_helper< + typename std::decay<BufferSequence>::type>::type; +#else +using buffers_iterator_type = + decltype(net::buffer_sequence_begin( + std::declval<BufferSequence const&>())); +#endif + +/** Return the total number of bytes in a buffer or buffer sequence + + This function returns the total number of bytes in a buffer, + buffer sequence, or object convertible to a buffer. Specifically + it may be passed: + + @li A <em>ConstBufferSequence</em> or <em>MutableBufferSequence</em> + + @li A `net::const_buffer` or `net::mutable_buffer` + + @li An object convertible to `net::const_buffer` + + This function is designed as an easier-to-use replacement for + `net::buffer_size`. It recognizes customization points found through + argument-dependent lookup. The call `beast::buffer_bytes(b)` is + equivalent to performing: + @code + using namespace net; + buffer_bytes(b); + @endcode + In addition this handles types which are convertible to + `net::const_buffer`; these are not handled by `net::buffer_size`. + + @param buffers The buffer or buffer sequence to calculate the size of. + + @return The total number of bytes in the buffer or sequence. +*/ +#if BOOST_BEAST_DOXYGEN +template<class BufferSequence> +std::size_t +buffer_bytes(BufferSequence const& buffers); +#else +BOOST_BEAST_INLINE_VARIABLE(buffer_bytes, detail::buffer_bytes_impl) +#endif + +} // beast +} // boost + +#endif |