Merge pull request #13378 from jordan-woyak/desired-ext-state

WiimoteEmu: Clean up variant handling in DesiredExtensionState.

Source/Core/Common/VariantUtil.h

@@ -34,3 +34,18 @@ struct overloaded : Ts...
 
 template <class... Ts>
 overloaded(Ts...) -> overloaded<Ts...>;
+
+// Visits a functor with a variant_alternative of the given index.
+// e.g. WithVariantAlternative<variant<int, float>>(1, func) calls func<float>()
+// An out-of-bounds index causes no visitation.
+template <typename Variant, std::size_t I = 0, typename Func>
+void WithVariantAlternative(std::size_t index, Func&& func)
+{
+  if constexpr (I < std::variant_size_v<Variant>)
+  {
+    if (index == 0)
+      func.template operator()<std::variant_alternative_t<I, Variant>>();
+    else
+      WithVariantAlternative<Variant, I + 1>(index - 1, std::forward<Func>(func));
+  }
+}

Source/Core/Core/HW/WiimoteEmu/DesiredWiimoteState.cpp

@@ -10,16 +10,8 @@
 
 #include "Common/BitUtils.h"
 #include "Common/CommonTypes.h"
+#include "Common/VariantUtil.h"
 
-#include "Core/HW/WiimoteEmu/Extension/Classic.h"
-#include "Core/HW/WiimoteEmu/Extension/DrawsomeTablet.h"
-#include "Core/HW/WiimoteEmu/Extension/Drums.h"
-#include "Core/HW/WiimoteEmu/Extension/Guitar.h"
-#include "Core/HW/WiimoteEmu/Extension/Nunchuk.h"
-#include "Core/HW/WiimoteEmu/Extension/Shinkansen.h"
-#include "Core/HW/WiimoteEmu/Extension/TaTaCon.h"
-#include "Core/HW/WiimoteEmu/Extension/Turntable.h"
-#include "Core/HW/WiimoteEmu/Extension/UDrawTablet.h"
 #include "Core/HW/WiimoteEmu/MotionPlus.h"
 
 namespace WiimoteEmu
@@ -114,13 +106,9 @@ SerializedWiimoteState SerializeDesiredState(const DesiredWiimoteState& state)
     std::visit(
         [&s](const auto& arg) {
           using T = std::decay_t<decltype(arg)>;
-          if constexpr (!std::is_same_v<std::monostate, T>)
+          static_assert(sizeof(arg) <= 6);
-          {
+          Common::BitCastPtr<T>(&s.data[s.length]) = arg;
-            static_assert(sizeof(arg) <= 6);
+          s.length += sizeof(arg);
-            static_assert(std::is_trivially_copyable_v<T>);
-            std::memcpy(&s.data[s.length], &arg, sizeof(arg));
-            s.length += sizeof(arg);
-          }
         },
         state.extension.data);
   }
@@ -128,19 +116,6 @@ SerializedWiimoteState SerializeDesiredState(const DesiredWiimoteState& state)
   return s;
 }
 
-template <typename T>
-static bool DeserializeExtensionState(DesiredWiimoteState* state,
-                                      const SerializedWiimoteState& serialized, size_t offset)
-{
-  if (serialized.length < offset + sizeof(T))
-    return false;
-  auto& e = state->extension.data.emplace<T>();
-  static_assert(std::is_trivially_copyable_v<T>);
-  std::memcpy(static_cast<void*>(&e), static_cast<const void*>(&serialized.data[offset]),
-              sizeof(T));
-  return true;
-}
-
 bool DeserializeDesiredState(DesiredWiimoteState* state, const SerializedWiimoteState& serialized)
 {
   // clear state
@@ -181,39 +156,10 @@ bool DeserializeDesiredState(DesiredWiimoteState* state, const SerializedWiimote
       s += 12;
     if (has_motion_plus)
       s += 6;
-    switch (extension)
+    if (extension)
     {
-    case ExtensionNumber::NONE:
+      WithVariantAlternative<DesiredExtensionState::ExtensionData>(
-      break;
+          extension, [&]<typename T>() { s += sizeof(T); });
-    case ExtensionNumber::NUNCHUK:
-      s += sizeof(Nunchuk::DataFormat);
-      break;
-    case ExtensionNumber::CLASSIC:
-      s += sizeof(Classic::DataFormat);
-      break;
-    case ExtensionNumber::GUITAR:
-      s += sizeof(Guitar::DataFormat);
-      break;
-    case ExtensionNumber::DRUMS:
-      s += sizeof(Drums::DesiredState);
-      break;
-    case ExtensionNumber::TURNTABLE:
-      s += sizeof(Turntable::DataFormat);
-      break;
-    case ExtensionNumber::UDRAW_TABLET:
-      s += sizeof(UDrawTablet::DataFormat);
-      break;
-    case ExtensionNumber::DRAWSOME_TABLET:
-      s += sizeof(DrawsomeTablet::DataFormat);
-      break;
-    case ExtensionNumber::TATACON:
-      s += sizeof(TaTaCon::DataFormat);
-      break;
-    case ExtensionNumber::SHINKANSEN:
-      s += sizeof(Shinkansen::DesiredState);
-      break;
-    default:
-      break;
     }
     return s;
   }();
@@ -283,32 +229,13 @@ bool DeserializeDesiredState(DesiredWiimoteState* state, const SerializedWiimote
     pos += 6;
   }
 
-  switch (extension)
+  if (extension)
   {
-  case ExtensionNumber::NONE:
+    WithVariantAlternative<DesiredExtensionState::ExtensionData>(extension, [&]<typename T>() {
-    return true;
+      state->extension.data.emplace<T>(Common::BitCastPtr<T>(&d[pos]));
-  case ExtensionNumber::NUNCHUK:
+    });
-    return DeserializeExtensionState<Nunchuk::DataFormat>(state, serialized, pos);
-  case ExtensionNumber::CLASSIC:
-    return DeserializeExtensionState<Classic::DataFormat>(state, serialized, pos);
-  case ExtensionNumber::GUITAR:
-    return DeserializeExtensionState<Guitar::DataFormat>(state, serialized, pos);
-  case ExtensionNumber::DRUMS:
-    return DeserializeExtensionState<Drums::DesiredState>(state, serialized, pos);
-  case ExtensionNumber::TURNTABLE:
-    return DeserializeExtensionState<Turntable::DataFormat>(state, serialized, pos);
-  case ExtensionNumber::UDRAW_TABLET:
-    return DeserializeExtensionState<UDrawTablet::DataFormat>(state, serialized, pos);
-  case ExtensionNumber::DRAWSOME_TABLET:
-    return DeserializeExtensionState<DrawsomeTablet::DataFormat>(state, serialized, pos);
-  case ExtensionNumber::TATACON:
-    return DeserializeExtensionState<TaTaCon::DataFormat>(state, serialized, pos);
-  case ExtensionNumber::SHINKANSEN:
-    return DeserializeExtensionState<Shinkansen::DesiredState>(state, serialized, pos);
-  default:
-    break;
   }
 
-  return false;
+  return true;
 }
 }  // namespace WiimoteEmu

Source/Core/Core/HW/WiimoteEmu/Extension/Classic.h

@@ -129,6 +129,8 @@ public:
   };
   static_assert(sizeof(DataFormat) == 6, "Wrong size");
 
+  using DesiredState = DataFormat;
+
   static constexpr int CAL_STICK_BITS = 8;
   static constexpr int CAL_TRIGGER_BITS = 8;
 

Source/Core/Core/HW/WiimoteEmu/Extension/DesiredExtensionState.h

@@ -3,7 +3,6 @@
 
 #pragma once
 
-#include <type_traits>
 #include <variant>
 
 #include "Common/BitUtils.h"
@@ -24,40 +23,38 @@ namespace WiimoteEmu
 {
 struct DesiredExtensionState
 {
-  using ExtensionData =
+private:
-      std::variant<std::monostate, Nunchuk::DataFormat, Classic::DataFormat, Guitar::DataFormat,
+  template <ExtensionNumber N, typename T>
-                   Drums::DesiredState, Turntable::DataFormat, UDrawTablet::DataFormat,
+  struct ExtNumTypePair
-                   DrawsomeTablet::DataFormat, TaTaCon::DataFormat, Shinkansen::DesiredState>;
+  {
-  ExtensionData data = std::monostate();
+    static constexpr ExtensionNumber ext_num = N;
+    using ext_type = T;
+  };
 
-  static_assert(std::is_same_v<std::monostate,
+  template <typename... Ts>
-                               std::variant_alternative_t<ExtensionNumber::NONE, ExtensionData>>);
+  struct ExtDataImpl
-  static_assert(
+  {
-      std::is_same_v<Nunchuk::DataFormat,
+    using type = std::variant<std::monostate, typename Ts::ext_type::DesiredState...>;
-                     std::variant_alternative_t<ExtensionNumber::NUNCHUK, ExtensionData>>);
+
-  static_assert(
+    static_assert((std::is_same_v<std::variant_alternative_t<Ts::ext_num, type>,
-      std::is_same_v<Classic::DataFormat,
+                                  typename Ts::ext_type::DesiredState> &&
-                     std::variant_alternative_t<ExtensionNumber::CLASSIC, ExtensionData>>);
+                   ...),
-  static_assert(std::is_same_v<Guitar::DataFormat,
+                  "Please use ExtensionNumber enum order for DTM file index consistency.");
-                               std::variant_alternative_t<ExtensionNumber::GUITAR, ExtensionData>>);
+  };
-  static_assert(std::is_same_v<Drums::DesiredState,
+
-                               std::variant_alternative_t<ExtensionNumber::DRUMS, ExtensionData>>);
+public:
-  static_assert(
+  using ExtensionData =
-      std::is_same_v<Turntable::DataFormat,
+      ExtDataImpl<ExtNumTypePair<ExtensionNumber::NUNCHUK, Nunchuk>,
-                     std::variant_alternative_t<ExtensionNumber::TURNTABLE, ExtensionData>>);
+                  ExtNumTypePair<ExtensionNumber::CLASSIC, Classic>,
-  static_assert(
+                  ExtNumTypePair<ExtensionNumber::GUITAR, Guitar>,
-      std::is_same_v<UDrawTablet::DataFormat,
+                  ExtNumTypePair<ExtensionNumber::DRUMS, Drums>,
-                     std::variant_alternative_t<ExtensionNumber::UDRAW_TABLET, ExtensionData>>);
+                  ExtNumTypePair<ExtensionNumber::TURNTABLE, Turntable>,
-  static_assert(
+                  ExtNumTypePair<ExtensionNumber::UDRAW_TABLET, UDrawTablet>,
-      std::is_same_v<DrawsomeTablet::DataFormat,
+                  ExtNumTypePair<ExtensionNumber::DRAWSOME_TABLET, DrawsomeTablet>,
-                     std::variant_alternative_t<ExtensionNumber::DRAWSOME_TABLET, ExtensionData>>);
+                  ExtNumTypePair<ExtensionNumber::TATACON, TaTaCon>,
-  static_assert(
+                  ExtNumTypePair<ExtensionNumber::SHINKANSEN, Shinkansen>>::type;
-      std::is_same_v<TaTaCon::DataFormat,
+
-                     std::variant_alternative_t<ExtensionNumber::TATACON, ExtensionData>>);
+  ExtensionData data = std::monostate{};
-  static_assert(
-      std::is_same_v<Shinkansen::DesiredState,
-                     std::variant_alternative_t<ExtensionNumber::SHINKANSEN, ExtensionData>>);
-  static_assert(std::variant_size_v<DesiredExtensionState::ExtensionData> == ExtensionNumber::MAX);
 };
 
 template <typename T>

Source/Core/Core/HW/WiimoteEmu/Extension/DrawsomeTablet.h

@@ -50,9 +50,10 @@ public:
       BitField<3, 5, u8> status;
     };
   };
-
   static_assert(6 == sizeof(DataFormat), "Wrong size.");
 
+  using DesiredState = DataFormat;
+
 private:
   ControllerEmu::AnalogStick* m_stylus;
   ControllerEmu::Triggers* m_touch;

Source/Core/Core/HW/WiimoteEmu/Extension/Guitar.h

@@ -48,6 +48,8 @@ public:
   };
   static_assert(sizeof(DataFormat) == 6, "Wrong size");
 
+  using DesiredState = DataFormat;
+
   Guitar();
 
   void BuildDesiredExtensionState(DesiredExtensionState* target_state) override;

Source/Core/Core/HW/WiimoteEmu/Extension/Nunchuk.h

@@ -116,6 +116,8 @@ public:
   };
   static_assert(sizeof(DataFormat) == 6, "Wrong size");
 
+  using DesiredState = DataFormat;
+
   struct CalibrationData
   {
     using StickType = DataFormat::StickType;

Source/Core/Core/HW/WiimoteEmu/Extension/TaTaCon.h

@@ -29,6 +29,8 @@ public:
   };
   static_assert(sizeof(DataFormat) == 6, "Wrong size");
 
+  using DesiredState = DataFormat;
+
   TaTaCon();
 
   void BuildDesiredExtensionState(DesiredExtensionState* target_state) override;

Source/Core/Core/HW/WiimoteEmu/Extension/Turntable.h

@@ -54,6 +54,8 @@ public:
   };
   static_assert(sizeof(DataFormat) == 6, "Wrong size");
 
+  using DesiredState = DataFormat;
+
   Turntable();
 
   void BuildDesiredExtensionState(DesiredExtensionState* target_state) override;

Source/Core/Core/HW/WiimoteEmu/Extension/UDrawTablet.h

@@ -56,9 +56,10 @@ public:
     // 0x04 is always unset (neutral state is 0xfb)
     u8 buttons;
   };
-
   static_assert(6 == sizeof(DataFormat), "Wrong size.");
 
+  using DesiredState = DataFormat;
+
 private:
   ControllerEmu::Buttons* m_buttons;
   ControllerEmu::AnalogStick* m_stylus;