ceph/src/boost/boost/beast/core/buffers_cat.hpp

   1 //
   2 // Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Official repository: https://github.com/boostorg/beast
   8 //
   9
  10 #ifndef BOOST_BEAST_BUFFERS_CAT_HPP
  11 #define BOOST_BEAST_BUFFERS_CAT_HPP
  12
  13 #include <boost/beast/core/detail/config.hpp>
  14 #include <boost/beast/core/detail/type_traits.hpp>
  15 #include <tuple>
  16
  17 namespace boost {
  18 namespace beast {
  19
  20 /** A buffer sequence representing a concatenation of buffer sequences.
  21
  22     @see @ref buffers_cat
  23 */
  24 template<class... Buffers>
  25 class buffers_cat_view
  26 {
  27     std::tuple<Buffers...> bn_;
  28
  29 public:
  30     /** The type of buffer returned when dereferencing an iterator.
  31
  32         If every buffer sequence in the view is a @b MutableBufferSequence,
  33         then `value_type` will be `boost::asio::mutable_buffer`.
  34         Otherwise, `value_type` will be `boost::asio::const_buffer`.
  35     */
  36 #if BOOST_BEAST_DOXYGEN
  37     using value_type = implementation_defined;
  38 #else
  39     using value_type = typename
  40         detail::common_buffers_type<Buffers...>::type;
  41 #endif
  42
  43     /// The type of iterator used by the concatenated sequence
  44     class const_iterator;
  45
  46     /// Constructor
  47     buffers_cat_view(buffers_cat_view&&) = default;
  48
  49     /// Assignment
  50     buffers_cat_view& operator=(buffers_cat_view&&) = default;
  51
  52     /// Assignment
  53     buffers_cat_view& operator=(buffers_cat_view const&) = default;
  54
  55     /** Constructor
  56
  57         @param buffers The list of buffer sequences to concatenate.
  58         Copies of the arguments will be made; however, the ownership
  59         of memory is not transferred.
  60     */
  61     explicit
  62     buffers_cat_view(Buffers const&... buffers);
  63
  64     //-----
  65
  66     /// Required for @b BufferSequence
  67     buffers_cat_view(buffers_cat_view const&) = default;
  68
  69     /// Required for @b BufferSequence
  70     const_iterator
  71     begin() const;
  72
  73     /// Required for @b BufferSequence
  74     const_iterator
  75     end() const;
  76 };
  77
  78 /** Concatenate 2 or more buffer sequences.
  79
  80     This function returns a constant or mutable buffer sequence which,
  81     when iterated, efficiently concatenates the input buffer sequences.
  82     Copies of the arguments passed will be made; however, the returned
  83     object does not take ownership of the underlying memory. The
  84     application is still responsible for managing the lifetime of the
  85     referenced memory.
  86
  87     @param buffers The list of buffer sequences to concatenate.
  88
  89     @return A new buffer sequence that represents the concatenation of
  90     the input buffer sequences. This buffer sequence will be a
  91     @b MutableBufferSequence if each of the passed buffer sequences is
  92     also a @b MutableBufferSequence; otherwise the returned buffer
  93     sequence will be a @b ConstBufferSequence.
  94
  95     @see @ref buffers_cat_view
  96 */
  97 #if BOOST_BEAST_DOXYGEN
  98 template<class... BufferSequence>
  99 buffers_cat_view<BufferSequence...>
 100 buffers_cat(BufferSequence const&... buffers)
 101 #else
 102 template<class B1, class B2, class... Bn>
 103 inline
 104 buffers_cat_view<B1, B2, Bn...>
 105 buffers_cat(B1 const& b1, B2 const& b2, Bn const&... bn)
 106 #endif
 107 {
 108     static_assert(
 109         detail::is_all_const_buffer_sequence<B1, B2, Bn...>::value,
 110             "BufferSequence requirements not met");
 111     return buffers_cat_view<B1, B2, Bn...>{b1, b2, bn...};
 112 }
 113
 114 } // beast
 115 } // boost
 116
 117 #include <boost/beast/core/impl/buffers_cat.ipp>
 118
 119 #endif