From 1e5e9219cd122761911bb426750af72c750c7efd Mon Sep 17 00:00:00 2001
From: mitaclaw <140017135+mitaclaw@users.noreply.github.com>
Date: Sun, 29 Sep 2024 14:07:27 -0700
Subject: [PATCH] Common: Create Range Projections For `std::pair`

---
 Source/Core/Common/CMakeLists.txt |  1 +
 Source/Core/Common/Projection.h   | 30 ++++++++++++++++++++++++++++++
 Source/Core/DolphinLib.props      |  1 +
 3 files changed, 32 insertions(+)
 create mode 100644 Source/Core/Common/Projection.h

diff --git a/Source/Core/Common/CMakeLists.txt b/Source/Core/Common/CMakeLists.txt
index 8f3eeb0a27..c368cde1d6 100644
--- a/Source/Core/Common/CMakeLists.txt
+++ b/Source/Core/Common/CMakeLists.txt
@@ -114,6 +114,7 @@ add_library(common
   PcapFile.h
   Profiler.cpp
   Profiler.h
+  Projection.h
   QoSSession.cpp
   QoSSession.h
   Random.cpp
diff --git a/Source/Core/Common/Projection.h b/Source/Core/Common/Projection.h
new file mode 100644
index 0000000000..d571508134
--- /dev/null
+++ b/Source/Core/Common/Projection.h
@@ -0,0 +1,30 @@
+// Copyright 2025 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <utility>
+
+namespace Common::Projection
+{
+struct First
+{
+  // TODO C++23: static operator()
+  template <class T>
+  [[nodiscard]] constexpr auto&& operator()(T&& t) const noexcept
+  {
+    return std::forward<T>(t).first;
+  }
+};
+
+struct Second
+{
+  // TODO C++23: static operator()
+  template <class T>
+  [[nodiscard]] constexpr auto&& operator()(T&& t) const noexcept
+  {
+    return std::forward<T>(t).second;
+  }
+};
+
+using Key = First;
+using Value = Second;
+}  // namespace Common::Projection
diff --git a/Source/Core/DolphinLib.props b/Source/Core/DolphinLib.props
index 367c347213..61cf4eddaa 100644
--- a/Source/Core/DolphinLib.props
+++ b/Source/Core/DolphinLib.props
@@ -144,6 +144,7 @@
     <ClInclude Include="Common\Network.h" />
     <ClInclude Include="Common\PcapFile.h" />
     <ClInclude Include="Common\Profiler.h" />
+    <ClInclude Include="Common\Projection.h" />
     <ClInclude Include="Common\QoSSession.h" />
     <ClInclude Include="Common\Random.h" />
     <ClInclude Include="Common\Result.h" />