alignment.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2014 John Wellbelove
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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******************************************************************************/
 
#ifndef ETL_ALIGNMENT_INCLUDED
#define ETL_ALIGNMENT_INCLUDED
 
#include "platform.h"
#include "type_traits.h"
#include "static_assert.h"
#include "error_handler.h"
#include "exception.h"
#include "utility.h"
#include "algorithm.h"
 
#include <stdint.h>

 
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  class alignment_exception : public etl::exception
  {
  public:
 
    alignment_exception(string_type reason_, string_type file_name_, numeric_type line_number_)
      : exception(reason_, file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class alignment_error : public alignment_exception
  {
  public:
 
    alignment_error(string_type file_name_, numeric_type line_number_)
      : alignment_exception(ETL_ERROR_TEXT("alignment:error", ETL_ALIGNMENT_FILE_ID"A"), file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class typed_storage_error : public alignment_exception
  {
  public:
 
    typed_storage_error(string_type file_name_, numeric_type line_number_)
      : alignment_exception(ETL_ERROR_TEXT("typed_storage:error", ETL_ALIGNMENT_FILE_ID"B"), file_name_, line_number_)
    {
    }
  };
 
  //*****************************************************************************
  //*****************************************************************************
  inline bool is_aligned(const void* p, size_t required_alignment)
  {
    uintptr_t address = reinterpret_cast<uintptr_t>(p);
    return (address % required_alignment) == 0U;
  }
 
  //*****************************************************************************
  //*****************************************************************************
  template <size_t Alignment>
  bool is_aligned(const void* p)
  {
    uintptr_t address = reinterpret_cast<uintptr_t>(p);
    return (address % Alignment) == 0U;
  }
 
  //*****************************************************************************
  //*****************************************************************************
  template <typename T>
  bool is_aligned(const void* p)
  {
    return is_aligned<etl::alignment_of<T>::value>(p);
  }
 
  namespace private_alignment
  {
#if ETL_USING_CPP11
    //***************************************************************************
    // Matcher.
    //***************************************************************************
    template <bool Is_Match, size_t Alignment, typename... TRest>
    class type_with_alignment_matcher;
 
    // Matching alignment.
    template <size_t Alignment, typename T1, typename... TRest>
    class type_with_alignment_matcher<true, Alignment, T1, TRest...> 
    {
    public:
    
      typedef T1 type;
    };
 
    // Non-matching alignment
    template <size_t Alignment, typename T1, typename T2, typename... TRest>
    class type_with_alignment_matcher <false, Alignment, T1, T2, TRest...> 
    {
    public:
    
      typedef typename type_with_alignment_matcher < Alignment <= etl::alignment_of<T2>::value , Alignment, T2, TRest... > ::type type;
    };
 
    // Non-matching alignment, none left.
    template <size_t Alignment, typename T1>
    class type_with_alignment_matcher <false, Alignment, T1> 
    {
    public:
    
      typedef char type;
    };
 
    //***************************************************************************
    // Helper.
    //***************************************************************************
    template <size_t Alignment, typename T1, typename... T>
    class type_with_alignment_helper 
    {
    public:
    
      typedef typename type_with_alignment_matcher<Alignment <= etl::alignment_of<T1>::value, Alignment, T1, T...>::type type;
    };
#else
    //***************************************************************************
    // Matcher.
    //***************************************************************************
    template <bool Is_Match, const size_t Alignment, typename T1 = void, typename T2 = void, typename T3 = void, typename T4 = void, 
                                                     typename T5 = void, typename T6 = void, typename T7 = void, typename T8 = void>
    class type_with_alignment_matcher;
 
    // Matching alignment.
    template <size_t Alignment, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8>
    class type_with_alignment_matcher <true, Alignment, T1, T2, T3, T4, T5, T6, T7, T8>
    {
    public:
 
      typedef T1 type;
    };
 
    // Non-matching alignment.
    template <size_t Alignment, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8>
    class type_with_alignment_matcher <false, Alignment, T1, T2, T3, T4, T5, T6, T7, T8>
    {
    public:
 
      typedef typename type_with_alignment_matcher<Alignment <= etl::alignment_of<T2>::value, Alignment, T2, T3, T4, T5, T6, T7, T8, void>::type type;
    };
 
    // Non-matching alignment, none left.
    template <size_t Alignment>
    class type_with_alignment_matcher <false, Alignment, void, void, void, void, void, void, void, void>
    {
    public:
 
      typedef char type;
    };
 
    //***************************************************************************
    // Helper.
    //***************************************************************************
    template <size_t Alignment, typename T1,        typename T2 = void, typename T3 = void, typename T4 = void,
                                typename T5 = void, typename T6 = void, typename T7 = void, typename T8 = void>
    class type_with_alignment_helper
    {
    public:
 
      typedef typename type_with_alignment_matcher<Alignment <= etl::alignment_of<T1>::value, Alignment, T1, T2, T3, T4, T5, T6, T7, T8>::type type;
    };
#endif
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Alignment>
  class type_with_alignment
  {
  public:
 
#if ETL_USING_CPP11
    typedef struct { alignas(Alignment) char dummy; } type;
#else
  #if ETL_NOT_USING_64BIT_TYPES
      typedef typename private_alignment::type_with_alignment_helper<Alignment, int_least8_t, int_least16_t, int32_t, float, double, void*>::type type;
  #else
      typedef typename private_alignment::type_with_alignment_helper<Alignment, int_least8_t, int_least16_t, int32_t, int64_t, float, double, void*>::type type;
  #endif
#endif
 
    ETL_STATIC_ASSERT(etl::alignment_of<type>::value == Alignment, "Unable to create the type with the specified alignment");
  };
 
#if ETL_USING_CPP11
  template <size_t Alignment>
  using type_with_alignment_t = typename type_with_alignment<Alignment>::type;
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Length, const size_t Alignment>
  struct aligned_storage
  {
    struct type
    {
      template <typename T>
      operator T& ()
      {
        ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
        T* t = *this;
        return *t;
      }

      template <typename T>
      operator const T& () const
      {
        ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
        const T* t = *this;
        return *t;
      }

      template <typename T>
      operator T* ()
      {
        ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
        return reinterpret_cast<T*>(data);
      }

      template <typename T>
      operator const T* () const
      {
        ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
        return reinterpret_cast<const T*>(data);
      }

      template <typename T>
      T& get_reference()
      {
        ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
        T* t = *this;
        return *t;
      }

      template <typename T>
      const T& get_reference() const
      {
        ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
        const T* t = *this;
        return *t;
      }

      template <typename T>
      T* get_address()
      {
        ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
        return reinterpret_cast<T*>(data);
      }

      template <typename T>
      const T* get_address() const
      {
        ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
        return reinterpret_cast<const T*>(data);
      }
 
#if ETL_USING_CPP11 && !defined(ETL_COMPILER_ARM5)
      alignas(Alignment) char data[Length];
#else
      union
      {
        char data[Length];
        typename etl::type_with_alignment<Alignment>::type etl_alignment_type; // A POD type that has the same alignment as Alignment.
      };
#endif
    };
  };
 
#if ETL_USING_CPP11
  template <size_t Length, const size_t Alignment>
  using aligned_storage_t = typename aligned_storage<Length, Alignment>::type;
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Length, typename T>
  struct aligned_storage_as : public etl::aligned_storage<Length, etl::alignment_of<T>::value>
  {
  };
 
#if ETL_USING_CPP11
  template <size_t Length, typename T>
  using aligned_storage_as_t = typename aligned_storage_as<Length, T>::type;
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class typed_storage
  {
  public:
 
    typedef T        value_type;
    typedef T&       reference;
    typedef const T& const_reference;
    typedef T*       pointer;
    typedef const T* const_pointer;
 
    //***************************************************************************
    // Default constructor
    //***************************************************************************
    typed_storage() ETL_NOEXCEPT
      : valid(false)
    {
    }
 
#if ETL_USING_CPP11
    //***************************************************************************
    //***************************************************************************
    template <typename... TArgs>
    typed_storage(TArgs&&... args) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
      : valid(false)
    {
      create(etl::forward<TArgs>(args)...);
    }
#else
    //***************************************************************************
    //***************************************************************************
    template <typename T1>
    typed_storage(const T1& t1)
      : valid(false)
    {
      create(t1);
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2>
    typed_storage(const T1& t1, const T2& t2)
      : valid(false)
    {
      create(t1, t2);
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2, typename T3>
    typed_storage(const T1& t1, const T2& t2, const T3& t3)
      : valid(false)
    {
      create(t1, t2, t3);
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2, typename T3, typename T4>
    typed_storage(const T1& t1, const T2& t2, const T3& t3, const T4& t4)
      : valid(false)
    {
      create(t1, t2, t3, t4);
    }
#endif
 
    //***************************************************************************
    //***************************************************************************
    ~typed_storage() ETL_NOEXCEPT
    {
      // Intentionally empty.
    }
 
    //***************************************************************************
    //***************************************************************************
    bool has_value() const ETL_NOEXCEPT
    {
      return valid;
    }
 
#if ETL_USING_CPP11
    //***************************************************************************
    //***************************************************************************
    template <typename... TArgs>
    reference create(TArgs&&... args) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (&storage.value) value_type(etl::forward<TArgs>(args)...);
      valid = true;
      return *p;
    }
#else
    //***************************************************************************
    //***************************************************************************
    template <typename T1>
    reference create(const T1& t1)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (&storage.value) value_type(t1);
      valid = true;
      return *p;
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2>
    reference create(const T1& t1, const T2& t2)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (&storage.value) value_type(t1, t2);
      valid = true;
      return *p;
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2, typename T3>
    reference create(const T1& t1, const T2& t2, const T3& t3)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (&storage.value) value_type(t1, t2, t3);
      valid = true;
      return *p;
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2, typename T3, typename T4>
    reference create(const T1& t1, const T2& t2, const T3& t3, const T4& t4)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (&storage.value) value_type(t1, t2, t3, t4);
      valid = true;
      return *p;
    }
#endif
 
    //***************************************************************************
    //***************************************************************************
    void destroy() ETL_NOEXCEPT
    {
      if (has_value())
      {
        storage.value.~T();
        valid = false;
      }
    }
 
    //***************************************************************************
    //***************************************************************************
    pointer operator->() ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      ETL_ASSERT(has_value(), ETL_ERROR(etl::typed_storage_error));
 
      return &storage.value;
    }
 
    //***************************************************************************
    //***************************************************************************
    const_pointer operator->() const ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      ETL_ASSERT(has_value(), ETL_ERROR(etl::typed_storage_error));
      
      return &storage.value;
    }
 
    //***************************************************************************
    //***************************************************************************
    reference operator*() ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      return *operator->();
    }
 
    //***************************************************************************
    //***************************************************************************
    const_reference operator*() const ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      return *operator->();
    }
 
  private:
 
    typed_storage(etl::typed_storage<T>&) ETL_DELETE;
    typed_storage& operator =(etl::typed_storage<T>&) ETL_DELETE;
 
    struct dummy_t {};
 
   //*******************************
    union union_type
    {
      union_type() ETL_NOEXCEPT
        : dummy()
      {
      }
 
      ~union_type() ETL_NOEXCEPT
      {
      }
 
      dummy_t    dummy;
      value_type value;
    } storage;
 
    bool valid;
  };
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class typed_storage_ext
  {
  public:
 
    typedef T        value_type;
    typedef T&       reference;
    typedef const T& const_reference;
    typedef T*       pointer;
    typedef const T* const_pointer;
    
    template <typename U>
    friend ETL_CONSTEXPR14 void swap(typed_storage_ext<U>& lhs, typed_storage_ext<U>& rhs) ETL_NOEXCEPT;
 
    //***************************************************************************
    //***************************************************************************
    typed_storage_ext(void* pbuffer_) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
      : pbuffer(reinterpret_cast<T*>(pbuffer_)),
        valid(false)
    {
      ETL_ASSERT(etl::is_aligned(pbuffer_, etl::alignment_of<T>::value), ETL_ERROR(etl::alignment_error));
    }
 
#if ETL_USING_CPP11
    //***************************************************************************
    //***************************************************************************
    template <typename... TArgs>
    typed_storage_ext(void* pbuffer_, TArgs&&... args) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
      : pbuffer(reinterpret_cast<T*>(pbuffer_))
      , valid(false)
    {
      ETL_ASSERT(etl::is_aligned(pbuffer_, etl::alignment_of<T>::value), ETL_ERROR(etl::alignment_error));
      create(etl::forward<TArgs>(args)...);
    }
 
    //***************************************************************************
    //***************************************************************************
    typed_storage_ext(typed_storage_ext<T>&& other) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
      : pbuffer(other.pbuffer)
      , valid(other.valid)
    {
      other.pbuffer = ETL_NULLPTR;
      other.valid   = false;
    }
#else
    //***************************************************************************
    //***************************************************************************
    template <typename T1>
    typed_storage_ext(void* pbuffer_, const T1& t1)
      : pbuffer(reinterpret_cast<T*>(pbuffer_))
      , valid(false)
    {
      ETL_ASSERT(etl::is_aligned(pbuffer_, etl::alignment_of<T>::value), ETL_ERROR(etl::alignment_error));
      create(t1);
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2>
    typed_storage_ext(void* pbuffer_, const T1& t1, const T2& t2)
      : pbuffer(reinterpret_cast<T*>(pbuffer_))
      , valid(false)
    {
      ETL_ASSERT(etl::is_aligned(pbuffer_, etl::alignment_of<T>::value), ETL_ERROR(etl::alignment_error));
      create(t1, t2);
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2, typename T3>
    typed_storage_ext(void* pbuffer_, const T1& t1, const T2& t2, const T3& t3)
      : pbuffer(reinterpret_cast<T*>(pbuffer_))
      , valid(false)
    {
      ETL_ASSERT(etl::is_aligned(pbuffer_, etl::alignment_of<T>::value), ETL_ERROR(etl::alignment_error));
      create(t1, t2, t3);
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2, typename T3, typename T4>
    typed_storage_ext(void* pbuffer_, const T1& t1, const T2& t2, const T3& t3, const T4& t4)
      : pbuffer(reinterpret_cast<T*>(pbuffer_))
      , valid(false)
    {
      ETL_ASSERT(etl::is_aligned(pbuffer_, etl::alignment_of<T>::value), ETL_ERROR(etl::alignment_error));
      create(t1, t2, t3, t4);
    }
#endif
 
    //***************************************************************************
    //***************************************************************************
    ~typed_storage_ext() ETL_NOEXCEPT
    {
      // Intentionally empty.
    }
 
    //***************************************************************************
    //***************************************************************************
    bool has_value() const ETL_NOEXCEPT
    {
      return valid;
    }
 
#if ETL_USING_CPP11
    //***************************************************************************
    //***************************************************************************
    template <typename... TArgs>
    reference create(TArgs&&... args) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (pbuffer) value_type(etl::forward<TArgs>(args)...);
      valid = true;
      return *p;
    }
#else
    //***************************************************************************
    //***************************************************************************
    template <typename T1>
    reference create(const T1& t1)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (pbuffer) value_type(t1);
      valid = true;
      return *p;
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2>
    reference create(const T1& t1, const T2& t2)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (pbuffer) value_type(t1, t2);
      valid = true;
      return *p;
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2, typename T3>
    reference create(const T1& t1, const T2& t2, const T3& t3)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (pbuffer) value_type(t1, t2, t3);
      valid = true;
      return *p;
    }
 
    //***************************************************************************
    //***************************************************************************
    template <typename T1, typename T2, typename T3, typename T4>
    reference create(const T1& t1, const T2& t2, const T3& t3, const T4& t4)
    {
      ETL_ASSERT(!has_value(), ETL_ERROR(etl::typed_storage_error));
      pointer p = ::new (pbuffer) value_type(t1, t2, t3, t4);
      valid = true;
      return *p;
    }
#endif
 
    //***************************************************************************
    //***************************************************************************
    void destroy() ETL_NOEXCEPT
    {
      if (has_value())
      {
        pbuffer->~T();
        valid = false;
      }
    }
 
    //***************************************************************************
    //***************************************************************************
    pointer operator->() ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      ETL_ASSERT(has_value(), ETL_ERROR(etl::typed_storage_error));
 
      return pbuffer;
    }
 
    //***************************************************************************
    //***************************************************************************
    const_pointer operator->() const ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      ETL_ASSERT(has_value(), ETL_ERROR(etl::typed_storage_error));
 
      return pbuffer;
    }
 
    //***************************************************************************
    //***************************************************************************
    reference operator*() ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      return *operator->();
    }
 
    //***************************************************************************
    //***************************************************************************
    const_reference operator*() const ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      return *operator->();
    }
 
  private:
 
    typed_storage_ext(etl::typed_storage_ext<T>&) ETL_DELETE;
    typed_storage_ext& operator =(etl::typed_storage_ext<T>&) ETL_DELETE;
 
    pointer pbuffer;
    bool valid;
  };
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  ETL_CONSTEXPR14 void swap(etl::typed_storage_ext<T>& lhs, etl::typed_storage_ext<T>& rhs) ETL_NOEXCEPT
  {
    using ETL_OR_STD::swap;
 
    swap(lhs.pbuffer, rhs.pbuffer);
    swap(lhs.valid,   rhs.valid);
  }
}
 
#endif