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  #   ˆl–Ü4ý(”†»â‚À¹q§Å£Ã„Î‰ß¿Å ?÷     // <experimental/buffer> -*- C++ -*-

// Copyright (C) 2015-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file experimental/buffer
 *  This is a TS C++ Library header.
 *  @ingroup networking-ts
 */

#ifndef _GLIBCXX_EXPERIMENTAL_BUFFER
#define _GLIBCXX_EXPERIMENTAL_BUFFER 1

#pragma GCC system_header

#if __cplusplus >= 201402L

#include <array>
#include <string>
#include <system_error>
#include <vector>
#include <cstring>
#include <experimental/string_view>
#include <experimental/bits/net.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace experimental
{
namespace net
{
inline namespace v1
{

  /** @addtogroup networking-ts
   *  @{
   */

  enum class stream_errc {    // TODO decide values
    eof = 1,
    not_found = 2
  };

  const error_category& stream_category() noexcept // TODO not inline
  {
    struct __cat : error_category
    {
      const char* name() const noexcept { return "stream"; }

      std::string message(int __e) const
      {
	if (__e == (int)stream_errc::eof)
	  return "EOF";
	else if (__e == (int)stream_errc::not_found)
	  return "not found";
	return "stream";
      }

      virtual void __message(int) { } // TODO dual ABI XXX
    };
    static __cat __c;
    return __c;
  }

  inline error_code
  make_error_code(stream_errc __e) noexcept
  { return error_code(static_cast<int>(__e), stream_category()); }

  inline error_condition
  make_error_condition(stream_errc __e) noexcept
  { return error_condition(static_cast<int>(__e), stream_category()); }

  class mutable_buffer
  {
  public:
    // constructors:
    mutable_buffer() noexcept : _M_data(), _M_size() { }

    mutable_buffer(void* __p, size_t __n) noexcept
    : _M_data(__p), _M_size(__n) { }

    // members:
    void* data() const noexcept { return _M_data; }
    size_t size() const noexcept { return _M_size; }

  private:
    void*	_M_data;
    size_t	_M_size;
  };

  class const_buffer
  {
  public:
    // constructors:
    const_buffer() noexcept : _M_data(), _M_size() { }

    const_buffer(const void* __p, size_t __n) noexcept
    : _M_data(__p), _M_size(__n) { }

    const_buffer(const mutable_buffer& __b) noexcept
    : _M_data(__b.data()), _M_size(__b.size()) { }

    // members:
    const void* data() const noexcept { return _M_data; }
    size_t size() const noexcept { return _M_size; }

  private:
    const void*	_M_data;
    size_t	_M_size;
  };


  /** @brief buffer sequence access
   *
   * Uniform access to types that meet the BufferSequence requirements.
   * @{
   */

  inline const mutable_buffer*
  buffer_sequence_begin(const mutable_buffer& __b)
  { return std::addressof(__b); }

  inline const const_buffer*
  buffer_sequence_begin(const const_buffer& __b)
  { return std::addressof(__b); }

  inline const mutable_buffer*
  buffer_sequence_end(const mutable_buffer& __b)
  { return std::addressof(__b) + 1; }

  inline const const_buffer*
  buffer_sequence_end(const const_buffer& __b)
  { return std::addressof(__b) + 1; }

  template<typename _Cont>
    auto
    buffer_s