Use C++11 alignment primitives

base/memory/aligned_memory.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// AlignedMemory is a POD type that gives you a portable way to specify static
-// or local stack data of a given alignment and size. For example, if you need
-// static storage for a class, but you want manual control over when the object
-// is constructed and destructed (you don't want static initialization and
-// destruction), use AlignedMemory:
-//
-//   static AlignedMemory<sizeof(MyClass), ALIGNOF(MyClass)> my_class;
-//
-//   // ... at runtime:
-//   new(my_class.void_data()) MyClass();
-//
-//   // ... use it:
-//   MyClass* mc = my_class.data_as<MyClass>();
-//
-//   // ... later, to destruct my_class:
-//   my_class.data_as<MyClass>()->MyClass::~MyClass();
-//
-// Alternatively, a runtime sized aligned allocation can be created:
+#include <type_traits>
+
+// A runtime sized aligned allocation can be created:
 //
 //   float* my_array = static_cast<float*>(AlignedAlloc(size, alignment));
 //
 //   // ... later, to release the memory:
 //   AlignedFree(my_array);
 //
 // Or using unique_ptr:
 //
 //   std::unique_ptr<float, AlignedFreeDeleter> my_array(
 //       static_cast<float*>(AlignedAlloc(size, alignment)));
 
 #ifndef BASE_MEMORY_ALIGNED_MEMORY_H_
 #define BASE_MEMORY_ALIGNED_MEMORY_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/base_export.h"
 #include "base/compiler_specific.h"
 
 #if defined(COMPILER_MSVC)
 #include <malloc.h>
 #else
 #include <stdlib.h>
 #endif
 
 namespace base {
 
-// AlignedMemory is specialized for all supported alignments.
-// Make sure we get a compiler error if someone uses an unsupported alignment.
-template <size_t Size, size_t ByteAlignment>
-struct AlignedMemory {};
-
-#define BASE_DECL_ALIGNED_MEMORY(byte_alignment)                              \
-  template <size_t Size>                                                      \
-  class AlignedMemory<Size, byte_alignment> {                                 \
-   public:                                                                    \
-    ALIGNAS(byte_alignment) uint8_t data_[Size];                              \
-    void* void_data() { return static_cast<void*>(data_); }                   \
-    const void* void_data() const { return static_cast<const void*>(data_); } \
-    template <typename Type>                                                  \
-    Type* data_as() {                                                         \
-      return static_cast<Type*>(void_data());                                 \
-    }                                                                         \
-    template <typename Type>                                                  \
-    const Type* data_as() const {                                             \
-      return static_cast<const Type*>(void_data());                           \
-    }                                                                         \
-                                                                              \
-   private:                                                                   \
-    void* operator new(size_t);                                               \
-    void operator delete(void*);                                              \
-  }
-
-// Specialization for all alignments is required because MSVC (as of VS 2008)
-// does not understand ALIGNAS(ALIGNOF(Type)) or ALIGNAS(template_param).
-// Greater than 4096 alignment is not supported by some compilers, so 4096 is
-// the maximum specified here.
-BASE_DECL_ALIGNED_MEMORY(1);
-BASE_DECL_ALIGNED_MEMORY(2);
-BASE_DECL_ALIGNED_MEMORY(4);
-BASE_DECL_ALIGNED_MEMORY(8);
-BASE_DECL_ALIGNED_MEMORY(16);
-BASE_DECL_ALIGNED_MEMORY(32);
-BASE_DECL_ALIGNED_MEMORY(64);
-BASE_DECL_ALIGNED_MEMORY(128);
-BASE_DECL_ALIGNED_MEMORY(256);
-BASE_DECL_ALIGNED_MEMORY(512);
-BASE_DECL_ALIGNED_MEMORY(1024);
-BASE_DECL_ALIGNED_MEMORY(2048);
-BASE_DECL_ALIGNED_MEMORY(4096);
-
-#undef BASE_DECL_ALIGNED_MEMORY
-
+// This can be replaced with std::aligned_malloc when we have C++17.
 BASE_EXPORT void* AlignedAlloc(size_t size, size_t alignment);
 
 inline void AlignedFree(void* ptr) {
 #if defined(COMPILER_MSVC)
   _aligned_free(ptr);
 #else
   free(ptr);
 #endif
 }
 
 // Deleter for use with unique_ptr. E.g., use as
 //   std::unique_ptr<Foo, base::AlignedFreeDeleter> foo;
 struct AlignedFreeDeleter {
   inline void operator()(void* ptr) const {
     AlignedFree(ptr);
   }
 };
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_ALIGNED_MEMORY_H_