feature/compare2

examples/lookup.cpp

@@ -34,7 +34,8 @@ void lookup_api(libremidi::API api, const libremidi::input_port& searched)
   {
     // Check inputs.
     auto ports = midi.get_input_ports();
-    auto res = libremidi::find_closest_port(searched, ports);
+    auto res
+        = libremidi::find_closest_port(searched, std::span<const libremidi::input_port>(ports));
     if (res.found) {
       std::cout << "Found: " << *res.port << "\n";
     }

examples/utils.hpp

@@ -49,9 +49,9 @@ inline std::ostream& operator<<(std::ostream& s, const libremidi::container_iden
     void operator()(libremidi::uuid u) { s << "uuid"; }
     void operator()(std::string u) { s << u; }
     void operator()(uint64_t u) { s << u; }
-    void operator()(std::monostate) { }
+    void operator()(libremidi::monostate) { }
   } vis{s};
-  std::visit(vis, id);
+  visit(vis, id);
   return s;
 }
 
@@ -73,9 +73,9 @@ inline std::ostream& operator<<(std::ostream& s, const libremidi::device_identif
         << std::setfill('0') << std::setw(4) << (res & 0x0000FFFF);
       s.flags(f);
     }
-    void operator()(std::monostate) { }
+    void operator()(libremidi::monostate) { }
   } vis{s};
-  std::visit(vis, id);
+  visit(vis, id);
   return s;
 }
 

include/libremidi/backends.hpp

@@ -234,7 +234,7 @@ auto for_backend(libremidi::API api, F&& f)
 void for_input_configuration(auto f, libremidi::input_api_configuration& api_conf)
 {
   auto from_api = [&]<typename T>(T& /*backend*/) mutable {
-    if (auto conf = std::get_if<typename T::midi_in_configuration>(&api_conf))
+    if (auto conf = get_if<typename T::midi_in_configuration>(&api_conf))
     {
       f(*conf);
       return true;
@@ -249,7 +249,7 @@ void for_input_configuration(auto f, libremidi::input_api_configuration& api_con
 void for_output_configuration(auto f, libremidi::output_api_configuration& api_conf)
 {
   auto from_api = [&]<typename T>(T& /*backend*/) mutable {
-    if (auto conf = std::get_if<typename T::midi_out_configuration>(&api_conf))
+    if (auto conf = get_if<typename T::midi_out_configuration>(&api_conf))
     {
       f(*conf);
       return true;
@@ -264,7 +264,7 @@ void for_output_configuration(auto f, libremidi::output_api_configuration& api_c
 void for_observer_configuration(auto f, libremidi::observer_api_configuration& api_conf)
 {
   auto from_api = [&]<typename T>(T& /*backend*/) mutable {
-    if (auto conf = std::get_if<typename T::midi_observer_configuration>(&api_conf))
+    if (auto conf = get_if<typename T::midi_observer_configuration>(&api_conf))
     {
       f(*conf);
       return true;

include/libremidi/backends/alsa_seq/shared_handler.hpp

@@ -127,13 +127,13 @@ struct shared_handler : public libremidi::shared_context
           {
             case callback_added: {
               auto [addr, cb]
-                  = std::move(*std::get_if<libremidi::alsa_seq::poll_parameters>(&ev.payload));
+                  = std::move(*get_if<libremidi::alsa_seq::poll_parameters>(&ev.payload));
               addresses.push_back(addr);
               callbacks.push_back(std::move(cb));
               break;
             }
             case callback_removed:
-              auto addr = *std::get_if<snd_seq_addr_t>(&ev.payload);
+              auto addr = *get_if<snd_seq_addr_t>(&ev.payload);
               if (auto index = index_of_address(addr); index >= 0)
               {
                 addresses.erase(addresses.begin() + index);
@@ -179,7 +179,7 @@ struct shared_handler : public libremidi::shared_context
   struct event
   {
     event_type type;
-    std::variant<libremidi::alsa_seq::poll_parameters, snd_seq_addr_t> payload;
+    libremidi_variant_alias::variant<libremidi::alsa_seq::poll_parameters, snd_seq_addr_t> payload;
   };
 
   snd_seq_t* client{};

include/libremidi/backends/jack/shared_handler.hpp

@@ -70,11 +70,10 @@ struct shared_handler : public libremidi::shared_context
       switch (ev.type)
       {
         case in_callback_added:
-          midiin_callbacks.push_back(
-              std::move(*std::get_if<libremidi::jack_callback>(&ev.payload)));
+          midiin_callbacks.push_back(std::move(*get_if<libremidi::jack_callback>(&ev.payload)));
           break;
         case in_callback_removed: {
-          auto idx = *std::get_if<int64_t>(&ev.payload);
+          auto idx = *get_if<int64_t>(&ev.payload);
           for (auto it = midiin_callbacks.begin(); it != midiin_callbacks.end();)
           {
             if (it->token == idx)
@@ -90,11 +89,10 @@ struct shared_handler : public libremidi::shared_context
           break;
         }
         case out_callback_added:
-          midiout_callbacks.push_back(
-              std::move(*std::get_if<libremidi::jack_callback>(&ev.payload)));
+          midiout_callbacks.push_back(std::move(*get_if<libremidi::jack_callback>(&ev.payload)));
           break;
         case out_callback_removed:
-          auto idx = *std::get_if<int64_t>(&ev.payload);
+          auto idx = *get_if<int64_t>(&ev.payload);
           for (auto it = midiout_callbacks.begin(); it != midiout_callbacks.end();)
           {
             if (it->token == idx)
@@ -138,7 +136,7 @@ struct shared_handler : public libremidi::shared_context
   struct event
   {
     event_type type;
-    std::variant<libremidi::jack_callback, int64_t> payload;
+    libremidi_variant_alias::variant<libremidi::jack_callback, int64_t> payload;
   };
 
   boost::lockfree::spsc_queue<event> events{16};

include/libremidi/backends/pipewire/shared_handler.hpp

@@ -71,10 +71,10 @@ struct shared_handler : public libremidi::shared_context
       {
         case in_callback_added:
           midiin_callbacks.push_back(
-              std::move(*std::get_if<libremidi::pipewire_callback>(&ev.payload)));
+              std::move(*get_if<libremidi::pipewire_callback>(&ev.payload)));
           break;
         case in_callback_removed: {
-          auto idx = *std::get_if<int64_t>(&ev.payload);
+          auto idx = *get_if<int64_t>(&ev.payload);
           for (auto it = midiin_callbacks.begin(); it != midiin_callbacks.end();)
           {
             if (it->token == idx)
@@ -91,10 +91,10 @@ struct shared_handler : public libremidi::shared_context
         }
         case out_callback_added:
           midiout_callbacks.push_back(
-              std::move(*std::get_if<libremidi::pipewire_callback>(&ev.payload)));
+              std::move(*get_if<libremidi::pipewire_callback>(&ev.payload)));
           break;
         case out_callback_removed:
-          auto idx = *std::get_if<int64_t>(&ev.payload);
+          auto idx = *get_if<int64_t>(&ev.payload);
           for (auto it = midiout_callbacks.begin(); it != midiout_callbacks.end();)
           {
             if (it->token == idx)
@@ -138,7 +138,7 @@ struct shared_handler : public libremidi::shared_context
   struct event
   {
     event_type type;
-    std::variant<libremidi::pipewire_callback, int64_t> payload;
+    libremidi_variant_alias::variant<libremidi::pipewire_callback, int64_t> payload;
   };
 
   boost::lockfree::spsc_queue<event> events{16};

include/libremidi/backends/winmidi/midi_in.hpp

@@ -92,7 +92,7 @@ class midi_in_impl final
 
   stdx::error open_port(const input_port& port, std::string_view) override
   {
-    auto device_id = std::get_if<std::string>(&port.device);
+    auto device_id = get_if<std::string>(&port.device);
     if (!device_id)
       return std::errc::invalid_argument;
 

include/libremidi/backends/winmidi/midi_out.hpp

@@ -38,7 +38,7 @@ class midi_out_impl final
 
   stdx::error open_port(const output_port& port, std::string_view) override
   {
-    auto device_id = std::get_if<std::string>(&port.device);
+    auto device_id = get_if<std::string>(&port.device);
     if (!device_id)
       return std::errc::invalid_argument;
 

include/libremidi/cmidi2.hpp

@@ -6,6 +6,8 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#include <libremidi/config.hpp>
+
 #if !defined(_MSC_VER)
 #pragma GCC system_header
 #pragma clang system_header

include/libremidi/config.hpp

@@ -1,6 +1,6 @@
 #pragma once
-#ifndef LIBREMIDI_CONFIG_HPP
-  #define LIBREMIDI_CONFIG_HPP
+
+#define LIBREMIDI_VERSION "5.4.1"
 
 // clang-format off
 #if !defined(LIBREMIDI_BASE_NAMESPACE)
@@ -44,6 +44,7 @@
   #define WIN32_LEAN_AND_MEAN
 #endif
 
+// Dynamic exports
 #if defined(LIBREMIDI_EXPORTS) || defined(LIBREMIDI_MODULE_BUILD)
   #if defined(_MSC_VER)
     #define LIBREMIDI_EXPORT __declspec(dllexport)
@@ -54,8 +55,7 @@
   #define LIBREMIDI_EXPORT
 #endif
 
-#define LIBREMIDI_VERSION "5.4.1"
-
+// Boost check to prevent ABI issues
 #if defined(LIBREMIDI_USE_BOOST)
   #if !__has_include(<boost/container/small_vector.hpp>)
     #error \
@@ -67,8 +67,8 @@
   #endif
 #endif
 
+// Use boost::small_vector if available
 #if __has_include(<boost/container/small_vector.hpp>) && !defined(LIBREMIDI_NO_BOOST)
-
   #if LIBREMIDI_SLIM_MESSAGE > 0
     #include <boost/container/static_vector.hpp>
 NAMESPACE_LIBREMIDI
@@ -92,6 +92,54 @@ using midi_bytes = std::vector<unsigned char>;
 }
 #endif
 
+// Use boost::variant2 if available
+#define LIBREMIDI_NO_BOOST_VARIANT2 1
+#if __has_include(<boost/variant2.hpp>) && !defined(LIBREMIDI_NO_BOOST_VARIANT2)
+  #if __has_include(<boost/variant2.hpp>)
+    #include <boost/variant2.hpp>
+    #define LIBREMIDI_VARIANT_IS_BOOST_VARIANT2
+namespace libremidi_variant_alias = boost::variant2;
+  #endif
+#endif
+
+#if !defined(LIBREMIDI_VARIANT_IS_BOOST_VARIANT2)
+  #include <variant>
+namespace libremidi_variant_alias = std;
+#endif
+
+namespace libremidi
+{
+using monostate = libremidi_variant_alias::monostate;
+template <typename T>
+concept nothrow_move_constructible = std::is_nothrow_move_constructible_v<T>;
+
+template <nothrow_move_constructible... Args>
+using variant = libremidi_variant_alias::variant<Args...>;
+
+template <typename... Args>
+using slow_variant = libremidi_variant_alias::variant<Args...>;
+
+template <std::size_t N, typename T>
+using variant_element = libremidi_variant_alias::variant_alternative<N, T>;
+template <std::size_t N, typename T>
+using variant_element_t = libremidi_variant_alias::variant_alternative_t<N, T>;
+
+using libremidi_variant_alias::operator==;
+using libremidi_variant_alias::operator!=;
+using libremidi_variant_alias::operator<;
+using libremidi_variant_alias::operator>;
+using libremidi_variant_alias::operator<=;
+using libremidi_variant_alias::operator>=;
+
+// using boost::variant2::in_place;
+// using libremidi_variant_alias::in_place;
+using libremidi_variant_alias::get;
+using libremidi_variant_alias::get_if;
+using libremidi_variant_alias::in_place_index;
+using libremidi_variant_alias::in_place_type;
+using libremidi_variant_alias::visit;
+}
+
 #if __has_include(<midi/universal_packet.h>) && defined(LIBREMIDI_USE_NI_MIDI2)
   #define LIBREMIDI_NI_MIDI2_COMPAT 1
 #endif
@@ -107,4 +155,3 @@ using midi_bytes = std::vector<unsigned char>;
 #else
   #define LIBREMIDI_PRECONDITION(...)
 #endif
-#endif

include/libremidi/configurations.hpp

@@ -31,18 +31,18 @@ struct dummy_configuration
 {
 };
 
-using input_api_configuration = std::variant<
+using input_api_configuration = libremidi_variant_alias::variant<
     unspecified_configuration, dummy_configuration, alsa_raw_input_configuration,
     alsa_raw_ump::input_configuration, alsa_seq::input_configuration,
     alsa_seq_ump::input_configuration, coremidi_input_configuration,
     coremidi_ump::input_configuration, emscripten_input_configuration, jack_input_configuration,
-    kbd_input_configuration, kdmapi::input_configuration, libremidi::net::dgram_input_configuration,
-    libremidi::net_ump::dgram_input_configuration, pipewire_input_configuration,
-    winmidi::input_configuration, winmm_input_configuration, winuwp_input_configuration,
-    jack_ump::input_configuration, pipewire_ump::input_configuration, android::input_configuration,
-    libremidi::API>;
+    kbd_input_configuration, kdmapi::input_configuration,
+    libremidi::net::dgram_input_configuration, libremidi::net_ump::dgram_input_configuration,
+    pipewire_input_configuration, winmidi::input_configuration, winmm_input_configuration,
+    winuwp_input_configuration, jack_ump::input_configuration, pipewire_ump::input_configuration,
+    android::input_configuration, libremidi::API>;
 
-using output_api_configuration = std::variant<
+using output_api_configuration = libremidi_variant_alias::variant<
     unspecified_configuration, dummy_configuration, alsa_raw_output_configuration,
     alsa_raw_ump::output_configuration, alsa_seq::output_configuration,
     alsa_seq_ump::output_configuration, coremidi_output_configuration,
@@ -53,7 +53,7 @@ using output_api_configuration = std::variant<
     jack_ump::output_configuration, pipewire_ump::output_configuration,
     android::output_configuration, libremidi::API>;
 
-using observer_api_configuration = std::variant<
+using observer_api_configuration = libremidi_variant_alias::variant<
     unspecified_configuration, dummy_configuration, alsa_raw_observer_configuration,
     alsa_raw_ump::observer_configuration, alsa_seq::observer_configuration,
     alsa_seq_ump::observer_configuration, coremidi_observer_configuration,

include/libremidi/detail/memory.hpp

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <libremidi/config.hpp>
+
 #include <memory>
 #include <mutex>
 

include/libremidi/libremidi.cpp

@@ -59,7 +59,7 @@ libremidi::API midi_api(const input_api_configuration& conf)
 {
   libremidi::API ret = libremidi::API::UNSPECIFIED;
   midi_any::for_all_backends([&]<typename T>(T) {
-    if (std::get_if<typename T::midi_in_configuration>(&conf))
+    if (get_if<typename T::midi_in_configuration>(&conf))
     {
       ret = T::API;
     }
@@ -71,7 +71,7 @@ libremidi::API midi_api(const output_api_configuration& conf)
 {
   libremidi::API ret = libremidi::API::UNSPECIFIED;
   midi_any::for_all_backends([&]<typename T>(T) {
-    if (std::get_if<typename T::midi_out_configuration>(&conf))
+    if (get_if<typename T::midi_out_configuration>(&conf))
     {
       ret = T::API;
     }
@@ -83,7 +83,7 @@ libremidi::API midi_api(const observer_api_configuration& conf)
 {
   libremidi::API ret = libremidi::API::UNSPECIFIED;
   midi_any::for_all_backends([&]<typename T>(T) {
-    if (std::get_if<typename T::midi_observer_configuration>(&conf))
+    if (get_if<typename T::midi_observer_configuration>(&conf))
     {
       ret = T::API;
     }

include/libremidi/midi_in.cpp

@@ -67,7 +67,7 @@ make_midi_in(auto base_conf, input_api_configuration api_conf, auto backends)
   assert(base_conf.on_message || base_conf.on_raw_data);
 
   auto from_api = [&]<typename T>(T& /*backend*/) mutable {
-    if (auto conf = std::get_if<typename T::midi_in_configuration>(&api_conf))
+    if (auto conf = get_if<typename T::midi_in_configuration>(&api_conf))
     {
       ptr = libremidi::make<typename T::midi_in>(std::move(base_conf), std::move(*conf));
       return true;
@@ -135,11 +135,11 @@ LIBREMIDI_STATIC_INLINE_IMPLEMENTATION std::unique_ptr<midi_in_api> make_midi1_i
 LIBREMIDI_STATIC_INLINE_IMPLEMENTATION std::unique_ptr<midi_in_api>
 make_midi1_in(const input_configuration& base_conf, const input_api_configuration& api_conf)
 {
-  if (std::get_if<unspecified_configuration>(&api_conf))
+  if (get_if<unspecified_configuration>(&api_conf))
   {
     return make_midi1_in(base_conf);
   }
-  else if (auto api_p = std::get_if<libremidi::API>(&api_conf))
+  else if (auto api_p = get_if<libremidi::API>(&api_conf))
   {
     if (*api_p == libremidi::API::UNSPECIFIED)
     {
@@ -233,11 +233,11 @@ LIBREMIDI_STATIC_INLINE_IMPLEMENTATION std::unique_ptr<midi_in_api> make_midi2_i
 LIBREMIDI_STATIC_INLINE_IMPLEMENTATION std::unique_ptr<midi_in_api>
 make_midi2_in(const ump_input_configuration& base_conf, const input_api_configuration& api_conf)
 {
-  if (std::get_if<unspecified_configuration>(&api_conf))
+  if (get_if<unspecified_configuration>(&api_conf))
   {
     return make_midi2_in(base_conf);
   }
-  else if (auto api_p = std::get_if<libremidi::API>(&api_conf))
+  else if (auto api_p = get_if<libremidi::API>(&api_conf))
   {
     if (*api_p == libremidi::API::UNSPECIFIED)
     {