cast_util: Add BitCast and BitCastPointee

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

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