From d8777dc2f6b7334103e5d9b9131143501fb2d4b9 Mon Sep 17 00:00:00 2001
From: John Wellbelove <john.wellbelove@asterconsulting.co.uk>
Date: Wed, 26 May 2021 11:09:02 +0100
Subject: [PATCH] Further updates to mem_type

---
 include/etl/experimental/mem_type.h | 91 +++++++++++++++++++++--------
 1 file changed, 67 insertions(+), 24 deletions(-)

diff --git a/include/etl/experimental/mem_type.h b/include/etl/experimental/mem_type.h
index 0b9532de..68a8c7b5 100644
--- a/include/etl/experimental/mem_type.h
+++ b/include/etl/experimental/mem_type.h
@@ -1,46 +1,68 @@
 #pragma once
-template <size_t Size_>
+
+#include <stdint.h>
+
+#include "../platform.h"
+#include "../memory.h"
+#include "../static_assert.h"
+
+//*****************************************************************************
+/// mem_type
+//*****************************************************************************
+template <size_t Size_ , size_t Alignment_>
 class mem_type
 {
 public:
 
-  static constexpr size_t Size = Size_;
+  static constexpr size_t Size      = Size_;
+  static constexpr size_t Alignment = Alignment_;
 
   //***********************************
-  template <size_t Other_Size>
-  mem_type(const mem_type<Other_Size& other)
+  template <size_t Other_Size, size_t Other_Alignment>
+  constexpr mem_type(const mem_type<Other_Size, Other_Alignment>& other)
   {
-    ETL_STATIC_ASSERT(Size >= Other_Size, "Other size is too large");
+    ETL_STATIC_ASSERT(Size      >= Other_Size,      "Other size is too large");
+    ETL_STATIC_ASSERT(Alignment >= Other_Alignment, "Other alignment incompatible");
 
     memcpy(buffer, other.buffer, Size_);
   }
 
   //***********************************
   template <typename T>
-  T& get()
+  constexpr T& get()
   {
+    ETL_STATIC_ASSERT(sizeof(T) <= Size, "Size of T is too large");
+    ETL_STATIC_ASSERT(Alignment >= etl::alignment_of<T>::value, "Alignment of T is incompatible");
+
     return *reinterpret_cast<T*>(buffer);
   }
 
   //***********************************
   template <typename T>
-  const T& get() const
+  constexpr const T& get() const
   {
+    ETL_STATIC_ASSERT(sizeof(T) <= Size, "Size of T is too large");
+    ETL_STATIC_ASSERT(Alignment >= etl::alignment_of<T>::value, "Alignment of T is incompatible");
+
     return *reinterpret_cast<T*>(buffer);
   }
 
   //***********************************
   template <typename T>
-  operator T() const
+  constexpr operator T() const
   {
+    ETL_STATIC_ASSERT(sizeof(T) <= Size, "Size of T is too large");
+    ETL_STATIC_ASSERT(Alignment >= etl::alignment_of<T>::value, "Alignment of T is incompatible");
+
     return *reinterpret_cast<T*>(buffer);
   }
 
   //***********************************
-  template <size_t Other_Size>
-  mem_type& operator =(const mem_type<Other_Size>& rhs)
+  template <size_t Other_Size, size_t Other_Alignment>
+  constexpr mem_type& operator =(const mem_type<Other_Size, Other_Alignment>& rhs)
   {
     ETL_STATIC_ASSERT(Size >= Other_Size, "RHS size is too large");
+    ETL_STATIC_ASSERT(Alignment >= Other_Alignment, "RHS alignment incompatible");
 
     memcpy(buffer, rhs.buffer, Size_);
 
@@ -53,17 +75,26 @@ public:
     return Size;
   }
 
+  //***********************************
+  constexpr size_t alignment() const
+  {
+    return Alignment;
+  }
+
   //***********************************
   constexpr char* data() const
   {
-      return buffer;
+    return buffer;
   }
 
 private:
 
-  char buffer[Size]
+  etl::aligned_storage<Size, Alignment> buffer;
 };
 
+//*****************************************************************************
+/// mem_type_ptr
+//*****************************************************************************
 template <size_t Size_>
 class mem_type_ptr
 {
@@ -72,45 +103,57 @@ public:
   static constexpr size_t Size = Size_;
 
   //***********************************
-  mem_type_ptr()
+  constexpr mem_type_ptr()
     : pbuffer(ETL_NULLPTR)
   {
   }
 
   //***********************************
-  mem_type_ptr(char* pbuffer_)
+  constexpr mem_type_ptr(char* pbuffer_)
     : pbuffer(pbuffer_)
   {
   }
 
   //***********************************
   template <size_t Other_Size>
-  mem_type_ptr(const mem_type_ptr<Other_Size& other, char* pbuffer_)
+  constexpr mem_type_ptr(const mem_type_ptr<Other_Size& other, char* pbuffer_)
     : pbuffer(pbuffer_)
   {
-      ETL_STATIC_ASSERT(Size >= Other_Size, "Other size is too large");
+    ETL_STATIC_ASSERT(Size >= Other_Size, "Other size is too large");
 
-      memcpy(buffer, other.buffer, Size_);
+    memcpy(buffer, other.buffer, Size_);
+  }
+
+  //***********************************
+  void set(char* pbuffer_)
+  {
+    pbuffer = pbuffer_;
   }
 
   //***********************************
   template <typename T>
-  T& get()
+  constexpr T& get()
   {
+    ETL_STATIC_ASSERT((uintptr_t(pbuffer) % etl::alignment_of<T>::value) == 0, "Alignment of T is incompatible");
+
     return *reinterpret_cast<T*>(pbuffer);
   }
 
   //***********************************
   template <typename T>
-  const T& get() const
+  constexpr const T& get() const
   {
+    ETL_STATIC_ASSERT((uintptr_t(pbuffer) % etl::alignment_of<T>::value) == 0, "Alignment of T is incompatible");
+
     return *reinterpret_cast<T*>(pbuffer);
   }
 
   //***********************************
   template <typename T>
-  operator T() const
+  constexpr operator T() const
   {
+    ETL_STATIC_ASSERT((uintptr_t(pbuffer) % etl::alignment_of<T>::value) == 0, "Alignment of T is incompatible");
+
     return *reinterpret_cast<T*>(pbuffer);
   }
 
@@ -118,11 +161,11 @@ public:
   template <size_t Other_Size>
   mem_type_ptr& operator =(const mem_type_ptr<Other_Size>& rhs)
   {
-      ETL_STATIC_ASSERT(Size >= Other_Size, "RHS size is too large");
+    ETL_STATIC_ASSERT(Size >= Other_Size, "RHS size is too large");
 
-      memcpy(pbuffer, rhs.pbuffer, Size_);
+    memcpy(pbuffer, rhs.pbuffer, Size_);
 
-      return *this;
+    return *this;
   }
 
   //***********************************
@@ -134,7 +177,7 @@ public:
   //***********************************
   constexpr char* data() const
   {
-      return pbuffer;
+    return pbuffer;
   }
 
 private: