[wip] net backend

cmake/libremidi.net.cmake

@@ -0,0 +1,16 @@
+if(NOT TARGET Boost::boost)
+  return()
+endif()
+
+  message(STATUS "libremidi: using Boost.ASIO")
+  set(LIBREMIDI_HAS_BOOST_ASIO 1)
+
+  target_compile_definitions(libremidi
+    ${_public}
+      LIBREMIDI_NET
+  )
+  target_link_libraries(libremidi
+    ${_public}
+      $<BUILD_INTERFACE:Boost::boost>
+  )
+endif()

include/libremidi/backends/net/config.hpp

@@ -0,0 +1,51 @@
+#pragma once
+#include <libremidi/config.hpp>
+
+#include <boost/asio.hpp>
+
+#include <string>
+namespace boost::asio
+{
+struct io_context;
+}
+
+namespace libremidi
+{
+enum class net_protocol
+{
+  RTPMIDI,
+  APPLEMIDI,
+  LIBREMIDI_DGRAM_MIDI1,
+  LIBREMIDI_DGRAM_MIDI2
+};
+
+struct net_dgram_input_configuration
+{
+  std::string client_name = "libremidi client";
+
+  net_protocol protocol = net_protocol::LIBREMIDI_DGRAM_MIDI1;
+  std::string accept = "0.0.0.0";
+  int port{};
+
+  boost::asio::io_context* io_context{};
+};
+
+struct net_dgram_output_configuration
+{
+  std::string client_name = "libremidi client";
+
+  net_protocol protocol = net_protocol::LIBREMIDI_DGRAM_MIDI1;
+  std::string host = "127.0.0.1";
+  int port{};
+
+  boost::asio::io_context* io_context{};
+};
+
+struct net_dgram_observer_configuration
+{
+  std::string client_name = "libremidi client";
+
+  boost::asio::io_context* io_context{};
+};
+
+}

include/libremidi/backends/net/midi_out.hpp

@@ -0,0 +1,129 @@
+#pragma once
+#include <libremidi/backends/net/config.hpp>
+#include <libremidi/backends/net/helpers.hpp>
+#include <libremidi/detail/midi_out.hpp>
+
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/ip/udp.hpp>
+#include <boost/endian.hpp>
+
+namespace libremidi::net
+{
+
+class midi1_out_impl final
+    : public midi1::out_api
+    , public error_handler
+{
+public:
+  struct
+      : output_configuration
+      , net_dgram_output_configuration
+  {
+  } configuration;
+
+  midi1_out_impl(output_configuration&& conf, net_dgram_output_configuration&& apiconf)
+      : configuration{std::move(conf), std::move(apiconf)}
+      , ctx{new boost::asio::io_context}
+  {
+    m_socket.open(boost::asio::ip::udp::v4());
+    m_socket.set_option(boost::asio::ip::udp::socket::reuse_address(true));
+    m_socket.set_option(boost::asio::socket_base::broadcast(true));
+  }
+
+  ~midi_out_impl() override
+  {
+    close_port();
+
+    disconnect(*this);
+  }
+
+  stdx::error open_port(const output_port& port, std::string_view portName) override
+  {
+    const char* host = "127.0.0.1:1234";
+    const char* port = "/midi";
+    /*
+    if (auto err = create_local_port(*this, portName, JackPortIsOutput); err != stdx::error{})
+      return err;
+    
+    // Connecting to the output
+    if (int err = jack_connect(this->client, jack_port_name(this->port), port.port_name.c_str());
+        err != 0 && err != EEXIST)
+    {
+      libremidi_handle_error(
+          configuration, "could not connect to port" + port.port_name);
+      return from_errc(err);
+    }
+    */
+
+    return stdx::error{};
+  }
+
+  stdx::error open_virtual_port(std::string_view portName) override
+  {
+    // Random arbitrary limit to avoid abuse
+    if (portName.size() >= 512)
+      return std::errc::invalid_argument;
+
+    int i = 0;
+    for (; i < portName.size(); i++)
+      if (portName.data()[i] != 0)
+        bytes.data[i] = portName.data()[i];
+      else
+        break;
+    bytes.data[i] = 0;
+    while (i % 4 != 3)
+    {
+      ++i;
+      bytes.data[i] = 0;
+    }
+
+    bytes.data[++i] = ',';
+    bytes.data[++i] = 'm';
+    bytes.data[++i] = 0;
+    bytes.data[++i] = 0;
+    osc_header_size = i;
+
+    return stdx::error{};
+  }
+
+  stdx::error close_port() override { osc_header_size = 0; }
+
+  stdx::error send_message(const unsigned char* message, size_t size) override
+  {
+    if (osc_header_size == 0)
+      return std::errc::not_connected;
+
+    int ret = 0;
+    if (size > 65507)
+      return std::errc::message_size;
+
+    auto time = std::chrono::system_clock::now();
+
+    std::memcpy(this->msg.data + osc_header_size, message, size);
+    bytes.byte_size = size + osc_header_size;
+
+    return from_errc(ret);
+  }
+
+  struct msg
+  {
+    char bundle_text[8] = "\0#bundle";
+    boost::endian::big_int64_t timestamp = 0;
+    boost::endian::big_int32_t byte_size = 0;
+    char data[65535];
+  };
+  static_assert(sizeof(msg) == 8 + 8 + 4 + 65535);
+
+  stdx::error schedule_message(int64_t ts, const unsigned char* message, size_t size) override
+  {
+    int ret = 0;
+    return from_errc(ret);
+  }
+
+  boost::asio::io_context* ctx{};
+  boost::asio::ip::udp::socket sock;
+  msg bytes;
+  int osc_header_size{};
+};
+
+}