socket.hpp

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/* Copyright 2025 Kevin Exton
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#pragma once
#ifndef IO_SOCKET_WINDOWS_HPP
#define IO_SOCKET_WINDOWS_HPP
#include <cassert>
#include <ios>
#include <span>
#include <tuple>
 
#include <winsock2.h>
#include <ws2tcpip.h>
 
namespace io::socket {
using native_socket_type = ::SOCKET;
 
inline static constexpr native_socket_type INVALID_SOCKET = INVALID_SOCKET;
 
inline static constexpr int SOCKET_ERROR = ::SOCKET_ERROR;
 
using socket_buffer_type = std::span<char, std::dynamic_extent>;
 
using socket_message_type = ::WSAMSG;
 
inline auto close(native_socket_type socket) noexcept -> int {
  return ::closesocket(socket);
}
 
// POSIX fcntl constants
static constexpr int F_SETFL = 4;
static constexpr int O_NONBLOCK = 2048;
 
template <typename... Args>
inline auto fcntl(native_socket_type socket, int cmd,
                  Args &&...args) noexcept -> int {
  static_assert(sizeof...(args) == 1,
                "fcntl for windows is only implemented for F_SETFL and a "
                "single argument O_NONBLOCK.");
  assert(cmd == F_SETFL && "fcntl for windows is only implemented for F_SETFL");
 
  auto arg = std::get<0>(std::forward_as_tuple(std::forward<Args>(args)...));
  auto mode = (arg & O_NONBLOCK) ? 1 : 0;
  switch (cmd) {
  case F_SETFL:
    return ioctlsocket(socket, FIONBIO, &mode);
  default:
    return SOCKET_ERROR;
  }
}
 
inline auto sendmsg(native_socket_type socket, const socket_message_type *msg,
                    int flags) noexcept -> std::streamsize {
  std::streamsize len = 0;
  int error = ::WSASendMsg(socket, msg, &len, nullptr, nullptr);
  return (error == 0) ? len : error;
}
 
inline auto recvmsg(native_socket_type socket, socket_message_type *msg,
                    int flags) noexcept -> std::streamsize {
  std::streamsize len = 0;
  int error = ::WSARecvMsg(socket, msg, &len, nullptr, nullptr);
  return (error == 0) ? len : error;
}
 
using sockaddr_type = ::SOCKADDR;
 
using sockaddr_storage_type = ::SOCKADDR_STORAGE;
 
using socklen_type = int;
} // namespace io::socket
 
#endif // IO_SOCKET_WINDOWS_HPP