From afe16fa0f3be08438f7df12233455122b4cf48ba Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Wed, 7 Feb 2018 12:22:35 +0000
Subject: [PATCH] cast_util: Add BitCast and BitCastPointee

---
 src/CMakeLists.txt     |  1 +
 src/common/cast_util.h | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 src/common/cast_util.h

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index d22195aa..1986898a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -9,6 +9,7 @@ add_library(dynarmic
     common/aes.h
     common/assert.h
     common/bit_util.h
+    common/cast_util.h
     common/common_types.h
     common/crc32.cpp
     common/crc32.h
diff --git a/src/common/cast_util.h b/src/common/cast_util.h
new file mode 100644
index 00000000..5a756b5c
--- /dev/null
+++ b/src/common/cast_util.h
@@ -0,0 +1,38 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2018 MerryMage
+ * This software may be used and distributed according to the terms of the GNU
+ * General Public License version 2 or any later version.
+ */
+
+#pragma once
+
+#include <cstring>
+#include <type_traits>
+
+namespace Dynarmic::Common {
+
+/// Reinterpret objects of one type as another by bit-casting between object representations.
+template <class Dest, class Source>
+inline Dest BitCast(const Source& source) {
+    static_assert(sizeof(Dest) == sizeof(Source), "size of destination and source objects must be equal");
+    static_assert(std::is_trivially_copyable_v<Dest>, "destination type must be trivially copyable.");
+    static_assert(std::is_trivially_copyable_v<Source>, "source type must be trivially copyable");
+
+    typename std::aligned_storage_t<sizeof(Dest), alignof(Dest)> dest;
+    std::memcpy(&dest, &source, sizeof(dest));
+    return reinterpret_cast<Dest&>(dest);
+}
+
+/// Reinterpret objects of any arbitrary type as another type by bit-casting between object representations.
+/// Note that here we do not verify if source has enough bytes to read from.
+template <class Dest, class SourcePtr>
+inline Dest BitCastPointee(const SourcePtr source) {
+    static_assert(sizeof(SourcePtr) == sizeof(void*), "source pointer must have size of a pointer");
+    static_assert(std::is_trivially_copyable_v<Dest>, "destination type must be trivially copyable.");
+
+    typename std::aligned_storage_t<sizeof(Dest), alignof(Dest)> dest;
+    std::memcpy(&dest, BitCast<void*>(source), sizeof(dest));
+    return reinterpret_cast<Dest&>(dest);    
+}
+
+} // namespace Dynarmic::Common