bitset_new.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2022 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
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions :
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
******************************************************************************/
 
#ifndef ETL_BITSET_NEW_INCLUDED
#define ETL_BITSET_NEW_INCLUDED
 
#include "../platform.h"
#include "../algorithm.h"
#include "../binary.h"
#include "../char_traits.h"
#include "../enum_type.h"
#include "../error_handler.h"
#include "../exception.h"
#include "../integral_limits.h"
#include "../iterator.h"
#include "../largest.h"
#include "../log.h"
#include "../nullptr.h"
#include "../smallest.h"
#include "../span.h"
#include "../static_assert.h"
#include "../string.h"
 
#include <stddef.h>
#include <stdint.h>
#include <string.h>
 
#if ETL_USING_STL
  #include <algorithm>
#endif
 
#include "minmax_push.h"
 
#if defined(ETL_COMPILER_KEIL)
  #pragma diag_suppress 1300
#endif
 
#if ETL_USING_CPP11
  #define ETL_STR(x)  x
  #define ETL_STRL(x) L##x
  #define ETL_STRu(x) u##x
  #define ETL_STRU(x) U##x
#else
  #define ETL_STR(x)  x
  #define ETL_STRL(x) x
  #define ETL_STRu(x) x
  #define ETL_STRU(x) x
#endif
 
//*****************************************************************************
//*****************************************************************************
 
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  struct bitset_storage_model
  {
    enum enum_type
    {
      Undefined = 0,
      Single    = 1,
      Multi     = 2
    };
 
    ETL_DECLARE_ENUM_TYPE(bitset_storage_model, char)
    ETL_ENUM_TYPE(Undefined, "Undefined")
    ETL_ENUM_TYPE(Single,    "Single")
    ETL_ENUM_TYPE(Multi,     "Multi")
    ETL_END_ENUM_TYPE
  };
 
  //***************************************************************************
  //***************************************************************************
  class bitset_exception : public etl::exception
  {
  public:
 
    bitset_exception(string_type reason_, string_type file_name_, numeric_type line_number_)
      : exception(reason_, file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class bitset_string_too_small : public bitset_exception
  {
  public:
 
    bitset_string_too_small(string_type file_name_, numeric_type line_number_)
      : bitset_exception(ETL_ERROR_TEXT("bitset:type_too_small", ETL_BITSET_FILE_ID"A"), file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class bitset_overflow : public bitset_exception
  {
  public:
 
    bitset_overflow(string_type file_name_, numeric_type line_number_)
      : bitset_exception(ETL_ERROR_TEXT("bitset:overflow", ETL_BITSET_FILE_ID"B"), file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class bitset_invalid_buffer : public bitset_exception
  {
  public:
 
    bitset_invalid_buffer(string_type file_name_, numeric_type line_number_)
      : bitset_exception(ETL_ERROR_TEXT("bitset:invalid buffer", ETL_BITSET_FILE_ID"C"), file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  namespace private_bitset
  {
    template <typename TElement>
    class bitset_impl_common
    {
    public:
 
      typedef TElement        element_type;
      typedef TElement*       pointer;
      typedef const TElement* const_pointer;
      typedef size_t          size_type;
 
      static ETL_CONSTANT size_t   npos              = etl::integral_limits<size_t>::max;
      static ETL_CONSTANT size_t   Bits_Per_Element  = etl::integral_limits<TElement>::bits;
      static ETL_CONSTANT TElement All_Set_Element   = etl::integral_limits<TElement>::max;
      static ETL_CONSTANT TElement All_Clear_Element = element_type(0);
    };
 
    template <typename TElement>
    ETL_CONSTANT size_t bitset_impl_common<TElement>::npos;
 
    template <typename TElement>
    ETL_CONSTANT size_t bitset_impl_common<TElement>::Bits_Per_Element;
 
    template <typename TElement>
    ETL_CONSTANT TElement bitset_impl_common<TElement>::All_Set_Element;
 
    template <typename TElement>
    ETL_CONSTANT TElement bitset_impl_common<TElement>::All_Clear_Element;
  } // namespace private_bitset
 
  //*************************************************************************
  //*************************************************************************
  template <typename TElement, char Bitset_Layout>
  class bitset_impl;
 
  //*************************************************************************
  //*************************************************************************
  template <typename TElement>
  class bitset_impl<TElement, etl::bitset_storage_model::Single> : public etl::private_bitset::bitset_impl_common<TElement>
  {
  public:
 
    using typename etl::private_bitset::bitset_impl_common<TElement>::element_type;
    using typename etl::private_bitset::bitset_impl_common<TElement>::pointer;
    using typename etl::private_bitset::bitset_impl_common<TElement>::const_pointer;
 
    using etl::private_bitset::bitset_impl_common<TElement>::Bits_Per_Element;
    using etl::private_bitset::bitset_impl_common<TElement>::All_Set_Element;
    using etl::private_bitset::bitset_impl_common<TElement>::All_Clear_Element;
 
    using etl::private_bitset::bitset_impl_common<TElement>::npos;
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void set_all(pointer pbuffer, size_t /*number_of_elements*/, element_type top_mask) ETL_NOEXCEPT
    {
      *pbuffer = All_Set_Element & top_mask;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void set_position(pointer pbuffer, size_t position, bool value = true)
    {
      const element_type mask = element_type(element_type(1) << position);
 
      if (value == true)
      {
        *pbuffer |= mask;
      }
      else
      {
        *pbuffer &= ~mask;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position>
    static ETL_CONSTEXPR14 void set_position(pointer pbuffer, bool value = true)
    {
      const element_type mask = element_type(element_type(1) << Position);
 
      if (value == true)
      {
        *pbuffer |= mask;
      }
      else
      {
        *pbuffer &= ~mask;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position, bool Value>
    static ETL_CONSTEXPR14 void set_position(pointer pbuffer)
    {
      const element_type mask = element_type(element_type(1) << Position);
 
      if (Value == true)
      {
        *pbuffer |= mask;
      }
      else
      {
        *pbuffer &= ~mask;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void reset_all(pointer pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      *pbuffer = All_Clear_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14
 
      void
      reset_position(pointer pbuffer, size_t position)
    {
      const element_type mask = element_type(element_type(1) << position);
      *pbuffer &= ~mask;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void from_string(pointer pbuffer, size_t /*number_of_elements*/, size_t active_bits, const char* text) ETL_NOEXCEPT
    {
      reset_all(pbuffer, 1U);
 
      if (text != ETL_NULLPTR)
      {
        size_t string_length = etl::strlen(text);
 
        // Build from the string.
        string_length = etl::min(active_bits, string_length);
 
        if (string_length == 0U)
        {
          return;
        }
 
        element_type mask = element_type(element_type(1) << (string_length - 1U));
 
        for (size_t i = 0U; i < string_length; ++i)
        {
          if (text[i] == ETL_STR('1'))
          {
            *pbuffer |= mask;
          }
 
          mask >>= 1U;
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void from_string(pointer pbuffer, size_t /*number_of_elements*/, size_t active_bits, const wchar_t* text) ETL_NOEXCEPT
    {
      reset_all(pbuffer, 1U);
 
      if (text != ETL_NULLPTR)
      {
        size_t string_length = etl::strlen(text);
 
        // Build from the string.
        string_length = etl::min(active_bits, string_length);
 
        if (string_length == 0U)
        {
          return;
        }
 
        element_type mask = element_type(element_type(1) << (string_length - 1U));
 
        for (size_t i = 0U; i < string_length; ++i)
        {
          if (text[i] == ETL_STRL('1'))
          {
            *pbuffer |= mask;
          }
 
          mask >>= 1U;
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void from_string(pointer pbuffer, size_t /*number_of_elements*/, size_t active_bits, const char16_t* text) ETL_NOEXCEPT
    {
      reset_all(pbuffer, 1U);
 
      if (text != ETL_NULLPTR)
      {
        size_t string_length = etl::strlen(text);
 
        // Build from the string.
        string_length = etl::min(active_bits, string_length);
 
        if (string_length == 0U)
        {
          return;
        }
 
        element_type mask = element_type(element_type(1) << (string_length - 1U));
 
        for (size_t i = 0U; i < string_length; ++i)
        {
          if (text[i] == ETL_STRu('1'))
          {
            *pbuffer |= mask;
          }
 
          mask >>= 1U;
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void from_string(pointer pbuffer, size_t /*number_of_elements*/, size_t active_bits, const char32_t* text) ETL_NOEXCEPT
    {
      reset_all(pbuffer, 1U);
 
      if (text != ETL_NULLPTR)
      {
        size_t string_length = etl::strlen(text);
 
        // Build from the string.
        string_length = etl::min(active_bits, string_length);
 
        if (string_length == 0U)
        {
          return;
        }
 
        element_type mask = element_type(element_type(1) << (string_length - 1U));
 
        for (size_t i = 0U; i < string_length; ++i)
        {
          if (text[i] == ETL_STRU('1'))
          {
            *pbuffer |= mask;
          }
 
          mask >>= 1U;
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    static ETL_CONSTEXPR14 T value(const_pointer pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      return T(*pbuffer);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    static ETL_CONSTEXPR14 T extract(const_pointer pbuffer, size_t position, size_t length = etl::integral_limits<T>::bits)
    {
      typedef typename etl::make_unsigned<T>::type unsigned_t;
 
      const unsigned_t Mask  = etl::make_lsb_mask<unsigned_t>(length);
      const unsigned_t Shift = position % Bits_Per_Element;
 
      unsigned_t value = static_cast<unsigned_t>(*pbuffer >> Shift) & Mask;
 
      if ((length != etl::integral_limits<T>::bits) && etl::integral_limits<T>::is_signed)
      {
        value = static_cast<unsigned_t>(etl::sign_extend<T>(static_cast<T>(value), length));
      }
 
      return static_cast<T>(value);
    }
 
    //*************************************************************************
    //*************************************************************************
#if ETL_USING_CPP11
    template <typename T, size_t Position, size_t Length = etl::integral_limits<T>::bits>
#else
    template <typename T, size_t Position, size_t Length>
#endif
    static ETL_CONSTEXPR14 T extract(const_pointer pbuffer)
    {
      typedef typename etl::make_unsigned<T>::type unsigned_t;
 
      const unsigned_t Mask  = etl::make_lsb_mask<unsigned_t>(Length);
      const unsigned_t Shift = Position % Bits_Per_Element;
 
      unsigned_t value = static_cast<unsigned_t>(*pbuffer >> Shift) & Mask;
 
      if ((Length != etl::integral_limits<T>::bits) && etl::integral_limits<T>::is_signed)
      {
        value = static_cast<unsigned_t>(etl::sign_extend<T>(static_cast<T>(value), Length));
      }
 
      return static_cast<T>(value);
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool test(const_pointer pbuffer, size_t position)
    {
      const element_type mask = element_type(element_type(1) << position);
      return (*pbuffer & mask) != 0U;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 size_t count(const_pointer pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      return etl::count_bits(*pbuffer);
    }
 
    //*************************************************************************
    // Are all the bits sets?
    //*************************************************************************
    static ETL_CONSTEXPR14 bool all(const_pointer pbuffer, size_t /*number_of_elements*/, element_type top_mask) ETL_NOEXCEPT
    {
      return (*pbuffer & top_mask) == top_mask;
    }
 
    //*************************************************************************
    // Are all the mask bits sets?
    //*************************************************************************
    static ETL_CONSTEXPR14 bool all(const_pointer pbuffer, size_t /*number_of_elements*/, element_type top_mask, element_type mask) ETL_NOEXCEPT
    {
      return (*pbuffer & top_mask & mask) == mask;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool none(const_pointer pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      return *pbuffer == All_Clear_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool none(const_pointer pbuffer, size_t /*number_of_elements*/, element_type mask) ETL_NOEXCEPT
    {
      return (*pbuffer & mask) == All_Clear_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool any(const_pointer pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      return *pbuffer != All_Clear_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool any(const_pointer pbuffer, size_t /*number_of_elements*/, element_type mask) ETL_NOEXCEPT
    {
      return (*pbuffer & mask) != All_Clear_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void flip_all(pointer pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      *pbuffer = ~*pbuffer;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void flip_bits(pointer pbuffer, element_type mask = etl::integral_limits<element_type>::max) ETL_NOEXCEPT
    {
      *pbuffer ^= mask;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void flip_position(pointer pbuffer, size_t position)
    {
      const element_type mask = element_type(element_type(1) << position);
      *pbuffer ^= mask;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TString>
    static ETL_CONSTEXPR14 TString to_string(const_pointer pbuffer, size_t active_bits,
                                      typename TString::value_type zero = typename TString::value_type('0'),
                                      typename TString::value_type one  = typename TString::value_type('1'))
    {
      TString result;
 
      result.resize(active_bits, '\0');
 
      // Check that the string type can contain the digits.
      ETL_ASSERT_OR_RETURN_VALUE(result.size() == active_bits, ETL_ERROR(etl::bitset_string_too_small), result);
 
      for (size_t i = active_bits; i > 0; --i)
      {
        result[active_bits - i] = test(pbuffer, i - 1) ? one : zero;
      }
 
      return result;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 size_t find_next(const_pointer pbuffer, size_t /*number_of_elements*/, size_t active_bits, bool state, size_t position)
      ETL_NOEXCEPT
    {
      if (position < active_bits)
      {
        // Where to start.
        size_t bit = position;
 
        element_type mask = 1U << position;
 
        // Needs checking?
        if ((state && (*pbuffer != All_Clear_Element)) || (!state && (*pbuffer != All_Set_Element)))
        {
          // For each bit in the element...
          while (bit < active_bits)
          {
            // Equal to the required state?
            if (((*pbuffer & mask) != 0) == state)
            {
              return bit;
            }
 
            // Move on to the next bit.
            mask <<= 1;
            ++bit;
          }
        }
      }
 
      return npos;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_assignment(pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      *lhs_pbuffer = *rhs_pbuffer;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_and(pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      *lhs_pbuffer &= *rhs_pbuffer;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_or(pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      *lhs_pbuffer |= *rhs_pbuffer;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_xor(pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      *lhs_pbuffer ^= *rhs_pbuffer;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_not(pointer pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      *pbuffer = ~*pbuffer;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_shift_left(pointer pbuffer, size_t /*number_of_elements*/, size_t active_bits, size_t shift) ETL_NOEXCEPT
    {
      if (shift >= active_bits)
      {
        reset_all(pbuffer, 1U);
      }
      else
      {
        *pbuffer <<= shift;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_shift_right(pointer pbuffer, size_t /*number_of_elements*/, size_t active_bits, size_t shift) ETL_NOEXCEPT
    {
      if (shift >= active_bits)
      {
        reset_all(pbuffer, 1U);
      }
      else
      {
        *pbuffer >>= shift;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool operator_equality(const_pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      return (*lhs_pbuffer == *rhs_pbuffer);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TElementType>
    static ETL_CONSTEXPR14 void initialise(pointer pbuffer, size_t /*number_of_elements*/, unsigned long long value) ETL_NOEXCEPT
    {
      *pbuffer = static_cast<TElementType>(value);
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void swap(pointer lhs_pbuffer, pointer rhs_pbuffer, size_t /*number_of_elements*/) ETL_NOEXCEPT
    {
      element_type temp = *lhs_pbuffer;
      *lhs_pbuffer      = *rhs_pbuffer;
      *rhs_pbuffer      = temp;
    }
  };
 
  //*************************************************************************
  //*************************************************************************
  template <typename TElement>
  class bitset_impl<TElement, etl::bitset_storage_model::Multi> : public etl::private_bitset::bitset_impl_common<TElement>
  {
  private:
 
    typedef etl::private_bitset::bitset_impl_common<TElement> common;
 
  public:
 
    using typename etl::private_bitset::bitset_impl_common<TElement>::element_type;
    using typename etl::private_bitset::bitset_impl_common<TElement>::pointer;
    using typename etl::private_bitset::bitset_impl_common<TElement>::const_pointer;
 
    using etl::private_bitset::bitset_impl_common<TElement>::Bits_Per_Element;
    using etl::private_bitset::bitset_impl_common<TElement>::All_Set_Element;
    using etl::private_bitset::bitset_impl_common<TElement>::All_Clear_Element;
 
    using etl::private_bitset::bitset_impl_common<TElement>::npos;
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position, size_t Length, size_t Bits_Per_Element>
    struct value_is_in_one_element
    {
      static
        ETL_CONSTANT bool value = ((Position + Length - 1) >> etl::log2<Bits_Per_Element>::value) == (Position >> etl::log2<Bits_Per_Element>::value);
    };
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool test(const_pointer pbuffer, size_t position) ETL_NOEXCEPT
    {
      size_t       index = position >> etl::log2<Bits_Per_Element>::value;
      element_type mask  = element_type(1) << (position & (Bits_Per_Element - 1));
 
      return (pbuffer[index] & mask) != 0;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 size_t count(const_pointer pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      size_t count = 0;
 
      while (number_of_elements-- != 0)
      {
        count += etl::count_bits(*pbuffer++);
      }
 
      return count;
    }
 
    //*************************************************************************
    // Are all the bits sets?
    //*************************************************************************
    static ETL_CONSTEXPR14 bool all(const_pointer pbuffer, size_t number_of_elements, element_type top_mask) ETL_NOEXCEPT
    {
      // All but the last.
      while (number_of_elements-- != 1U)
      {
        if (*pbuffer++ != All_Set_Element)
        {
          return false;
        }
      }
 
      // The last.
      if ((*pbuffer & top_mask) != top_mask)
      {
        return false;
      }
 
      return true;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool none(const_pointer pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      while (number_of_elements-- != 0)
      {
        if (*pbuffer++ != 0)
        {
          return false;
        }
      }
 
      return true;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool any(const_pointer pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      bool any_set = false;
 
      while (number_of_elements-- != 0)
      {
        if (*pbuffer++ != All_Clear_Element)
        {
          any_set = true;
          break;
        }
      }
 
      return any_set;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void set_all(pointer pbuffer, size_t number_of_elements, element_type top_mask) ETL_NOEXCEPT
    {
      while (number_of_elements-- != 1U)
      {
        *pbuffer++ = All_Set_Element;
      }
 
      *pbuffer = (All_Set_Element & top_mask);
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void set_position(pointer pbuffer, size_t position, bool value = true) ETL_NOEXCEPT
    {
      size_t       index = position >> etl::log2<Bits_Per_Element>::value;
      element_type bit   = element_type(1) << (position & (Bits_Per_Element - 1));
 
      if (value == true)
      {
        pbuffer[index] |= bit;
      }
      else
      {
        pbuffer[index] &= ~bit;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position>
    static ETL_CONSTEXPR14 void set_position(pointer pbuffer, bool value = true)
    {
      size_t       index = Position >> etl::log2<Bits_Per_Element>::value;
      element_type bit   = element_type(1) << (Position & (Bits_Per_Element - 1));
 
      if (value == true)
      {
        pbuffer[index] |= bit;
      }
      else
      {
        pbuffer[index] &= ~bit;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position, bool Value>
    static ETL_CONSTEXPR14 void set_position(pointer pbuffer)
    {
      size_t       index = Position >> etl::log2<Bits_Per_Element>::value;
      element_type bit   = element_type(1) << (Position & (Bits_Per_Element - 1));
 
      if (Value == true)
      {
        pbuffer[index] |= bit;
      }
      else
      {
        pbuffer[index] &= ~bit;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void from_string(pointer pbuffer, size_t number_of_elements, size_t total_bits, const char* text) ETL_NOEXCEPT
    {
      if (text == ETL_NULLPTR)
      {
        etl::fill_n(pbuffer, number_of_elements, All_Clear_Element);
      }
      else
      {
        size_t string_length = etl::strlen(text);
        size_t index         = etl::min(number_of_elements - 1U, (string_length / Bits_Per_Element));
 
        // Only reset elements we need to.
        while (index != number_of_elements)
        {
          pbuffer[index++] = All_Clear_Element;
        }
 
        // Build from the string.
        size_t i = etl::min(total_bits, string_length);
 
        while (i > 0)
        {
          set_position(pbuffer, --i, *text++ == ETL_STR('1'));
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void from_string(pointer pbuffer, size_t number_of_elements, size_t total_bits, const wchar_t* text) ETL_NOEXCEPT
    {
      if (text == ETL_NULLPTR)
      {
        etl::fill_n(pbuffer, number_of_elements, All_Clear_Element);
      }
      else
      {
        size_t string_length = etl::strlen(text);
        size_t index         = etl::min(number_of_elements - 1U, (string_length / Bits_Per_Element));
 
        // Only reset elements we need to.
        while (index != number_of_elements)
        {
          pbuffer[index++] = All_Clear_Element;
        }
 
        // Build from the string.
        size_t i = etl::min(total_bits, string_length);
 
        while (i > 0)
        {
          set_position(pbuffer, --i, *text++ == ETL_STRL('1'));
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void from_string(pointer pbuffer, size_t number_of_elements, size_t total_bits, const char16_t* text) ETL_NOEXCEPT
    {
      if (text == ETL_NULLPTR)
      {
        etl::fill_n(pbuffer, number_of_elements, All_Clear_Element);
      }
      else
      {
        size_t string_length = etl::strlen(text);
        size_t index         = etl::min(number_of_elements - 1U, (string_length / Bits_Per_Element));
 
        // Only reset elements we need to.
        while (index != number_of_elements)
        {
          pbuffer[index++] = All_Clear_Element;
        }
 
        // Build from the string.
        size_t i = etl::min(total_bits, string_length);
 
        while (i > 0)
        {
          set_position(pbuffer, --i, *text++ == ETL_STRu('1'));
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void from_string(pointer pbuffer, size_t number_of_elements, size_t total_bits, const char32_t* text) ETL_NOEXCEPT
    {
      if (text == ETL_NULLPTR)
      {
        etl::fill_n(pbuffer, number_of_elements, All_Clear_Element);
      }
      else
      {
        size_t string_length = etl::strlen(text);
        size_t index         = etl::min(number_of_elements - 1U, (string_length / Bits_Per_Element));
 
        // Only reset elements we need to.
        while (index != number_of_elements)
        {
          pbuffer[index++] = All_Clear_Element;
        }
 
        // Build from the string.
        size_t i = etl::min(total_bits, string_length);
 
        while (i > 0)
        {
          set_position(pbuffer, --i, *text++ == ETL_STRU('1'));
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void reset_all(pointer pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      while (number_of_elements-- != 0U)
      {
        *pbuffer++ = All_Clear_Element;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void reset_position(pointer pbuffer, size_t position) ETL_NOEXCEPT
    {
      const size_t       index = position >> etl::log2<Bits_Per_Element>::value;
      const element_type bit   = element_type(1) << (position & (Bits_Per_Element - 1));
 
      pbuffer[index] &= ~bit;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    static ETL_CONSTEXPR14 T value(const_pointer pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      T v = T(0);
 
      const bool OK = (sizeof(T) * CHAR_BIT) >= (number_of_elements * Bits_Per_Element);
 
      if (OK)
      {
        uint_least8_t shift = 0U;
 
        for (size_t i = 0UL; i < number_of_elements; ++i)
        {
          v |= T(typename etl::make_unsigned<T>::type(pbuffer[i]) << shift);
          shift += uint_least8_t(Bits_Per_Element);
        }
      }
 
      return v;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    static ETL_CONSTEXPR14 typename etl::make_unsigned<T>::type extract_from_multiple_elements(const element_type* pbuffer, size_t element_index,
                                                                                        size_t active_bits_in_msb, size_t length) ETL_NOEXCEPT
    {
      typedef typename etl::make_unsigned<T>::type unsigned_t;
 
      unsigned_t value(0);
 
      // Extract the first element, if partially filled.
      if (active_bits_in_msb < Bits_Per_Element)
      {
        element_type mask = etl::make_lsb_mask< element_type>(active_bits_in_msb);
        value             = pbuffer[element_index] & mask;
        length -= active_bits_in_msb;
        if (length >= Bits_Per_Element)
        {
          value = value << Bits_Per_Element;
        }
        --element_index;
      }
 
      // Loop through the fully filled elements
      while (length >= Bits_Per_Element)
      {
        value |= pbuffer[element_index];
        length -= Bits_Per_Element;
        if (length >= Bits_Per_Element)
        {
          value = value << Bits_Per_Element;
        }
        --element_index;
      }
 
      // Extract the last element, if partially filled.
      if (length != 0)
      {
        value             = value << length;
        element_type mask = etl::make_lsb_mask< element_type>(length);
        value |= (pbuffer[element_index] >> (Bits_Per_Element - length)) & mask;
      }
 
      return value;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    static ETL_CONSTEXPR14 typename etl::make_unsigned<T>::type extract_from_buffer(const_pointer pbuffer, size_t position, size_t length)
      ETL_NOEXCEPT
    {
      typedef typename etl::make_unsigned<T>::type unsigned_t;
 
      unsigned_t value(0);
 
      const size_t Msb_Element_Index = (position + length - 1) >> etl::log2<Bits_Per_Element>::value;
      const size_t Lsb_Element_Index = position >> etl::log2<Bits_Per_Element>::value;
 
      // Is the value contained within one element?
      if (Msb_Element_Index == Lsb_Element_Index)
      {
        const unsigned_t Mask  = etl::make_lsb_mask< unsigned_t>(length);
        const unsigned_t Shift = position % Bits_Per_Element;
 
        value = static_cast<unsigned_t>(pbuffer[Msb_Element_Index] >> Shift) & Mask;
      }
      else
      {
        // Get the number of active bits in the msb element
        size_t active_bits_in_msb = (position + length) - (static_cast<size_t>(Msb_Element_Index) * Bits_Per_Element);
 
        // Start with index of the element containing the msb.
        size_t element_index = Msb_Element_Index;
 
        value = extract_from_multiple_elements<T>(pbuffer, element_index, active_bits_in_msb, length);
      }
 
      return value;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T, size_t Position, size_t Length>
    static ETL_CONSTEXPR14
      typename etl::enable_if< value_is_in_one_element<Position, Length, Bits_Per_Element>::value, typename etl::make_unsigned<T>::type>::type
      extract_from_buffer(const_pointer pbuffer)
    {
      typedef typename etl::make_unsigned<T>::type unsigned_t;
 
      const size_t     Element_Index = (Position + Length - 1) >> etl::log2<Bits_Per_Element>::value;
      const unsigned_t Mask          = etl::lsb_mask<unsigned_t, Length>::value;
      const unsigned_t Shift         = Position % Bits_Per_Element;
 
      return static_cast<unsigned_t>(pbuffer[Element_Index] >> Shift) & Mask;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T, size_t Position, size_t Length>
    static ETL_CONSTEXPR14
      typename etl::enable_if< !value_is_in_one_element<Position, Length, Bits_Per_Element>::value, typename etl::make_unsigned<T>::type>::type
      extract_from_buffer(const_pointer pbuffer)
    {
      // Start with index of the element containing the msb.
      const size_t Msb_Element_Index = (Position + Length - 1) >> etl::log2<Bits_Per_Element>::value;
 
      // Get the number of active bits in the first element
      const size_t Active_Bits_In_Msb = ((Position + Length - 1) % Bits_Per_Element) + 1;
 
      return extract_from_multiple_elements<T>(pbuffer, Msb_Element_Index, Active_Bits_In_Msb, Length);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    static ETL_CONSTEXPR14 T extract(const_pointer pbuffer, size_t position, size_t length = etl::integral_limits<T>::bits)
    {
      typedef typename etl::make_unsigned<T>::type unsigned_t;
 
      unsigned_t value = extract_from_buffer<unsigned_t>(pbuffer, position, length);
 
      if ((length != etl::integral_limits<T>::bits) && etl::integral_limits<T>::is_signed)
      {
        value = static_cast<unsigned_t>(etl::sign_extend<T>(static_cast<T>(value), length));
      }
 
      return static_cast<T>(value);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T, size_t Position, size_t Length>
    static ETL_CONSTEXPR14 T extract(const_pointer pbuffer)
    {
      typedef typename etl::make_unsigned<T>::type unsigned_t;
 
      unsigned_t value = extract_from_buffer<unsigned_t, Position, Length>(pbuffer);
 
      if ((Length != etl::integral_limits<T>::bits) && etl::integral_limits<T>::is_signed)
      {
        value = static_cast<unsigned_t>(etl::sign_extend<T>(static_cast<T>(value), Length));
      }
 
      return static_cast<T>(value);
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void flip_all(pointer pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      operator_not(pbuffer, number_of_elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void flip_position(pointer pbuffer, size_t position) ETL_NOEXCEPT
    {
      const size_t       index = position >> etl::log2<Bits_Per_Element>::value;
      const element_type bit   = element_type(1) << (position & (Bits_Per_Element - 1));
 
      pbuffer[index] ^= bit;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 size_t find_next(const_pointer pbuffer, size_t number_of_elements, size_t total_bits, bool state, size_t position)
      ETL_NOEXCEPT
    {
      // Where to start.
      size_t index = position >> log2<Bits_Per_Element>::value;
      size_t bit   = position & (Bits_Per_Element - 1);
 
      element_type mask = 1 << bit;
 
      // For each element in the bitset...
      while (index < number_of_elements)
      {
        element_type value = pbuffer[index];
 
        // Needs checking?
        if ((state && (value != All_Clear_Element)) || (!state && (value != All_Set_Element)))
        {
          // For each bit in the element...
          while ((bit < Bits_Per_Element) && (position < total_bits))
          {
            // Equal to the required state?
            if (((value & mask) != 0) == state)
            {
              return position;
            }
 
            // Move on to the next bit.
            mask <<= 1;
            ++position;
            ++bit;
          }
        }
        else
        {
          position += (Bits_Per_Element - bit);
        }
 
        // Start at the beginning for all other elements.
        bit  = 0;
        mask = 1;
 
        ++index;
      }
 
      return npos;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TString>
    static ETL_CONSTEXPR14 TString to_string(const_pointer pbuffer, size_t active_bits, typename TString::value_type zero, typename TString::value_type one)
    {
      TString result;
 
      result.resize(active_bits, '\0');
 
      // Check that the string type can contain the digits.
      ETL_ASSERT_OR_RETURN_VALUE(result.size() == active_bits, ETL_ERROR(etl::bitset_string_too_small), result);
 
      for (size_t i = active_bits; i > 0; --i)
      {
        result[active_bits - i] = test(pbuffer, i - 1) ? one : zero;
      }
 
      return result;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_assignment(pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      while (number_of_elements-- != 0)
      {
        *lhs_pbuffer = *rhs_pbuffer;
        ++lhs_pbuffer;
        ++rhs_pbuffer;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_and(pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      while (number_of_elements-- != 0)
      {
        *lhs_pbuffer &= *rhs_pbuffer;
        ++lhs_pbuffer;
        ++rhs_pbuffer;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_or(pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      while (number_of_elements-- != 0)
      {
        *lhs_pbuffer |= *rhs_pbuffer;
        ++lhs_pbuffer;
        ++rhs_pbuffer;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_xor(pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      while (number_of_elements-- != 0)
      {
        *lhs_pbuffer ^= *rhs_pbuffer;
        ++lhs_pbuffer;
        ++rhs_pbuffer;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_not(pointer pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      while (number_of_elements-- != 0)
      {
        *pbuffer = ~*pbuffer;
        ++pbuffer;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_shift_left(pointer pbuffer, size_t number_of_elements, size_t active_bits, size_t shift) ETL_NOEXCEPT
    {
      if (shift >= active_bits)
      {
        reset_all(pbuffer, number_of_elements);
      }
      else
      {
        // The place where the elements are split when shifting.
        const size_t split_position = Bits_Per_Element - (shift % Bits_Per_Element);
 
        // Where we are shifting from.
        int src_index = int(number_of_elements - (shift / Bits_Per_Element) - 1U);
 
        // Where we are shifting to.
        int dst_index = int(number_of_elements - 1U);
 
        // Shift control constants.
        const size_t lsb_shift = Bits_Per_Element - split_position;
        const size_t msb_shift = split_position;
 
        const element_type lsb_mask         = element_type(etl::integral_limits<element_type>::max >> (Bits_Per_Element - split_position));
        const element_type msb_mask         = etl::integral_limits<element_type>::max - lsb_mask;
        const element_type lsb_shifted_mask = element_type(lsb_mask << lsb_shift);
 
        // First lsb.
        element_type lsb   = element_type((pbuffer[src_index] & lsb_mask) << lsb_shift);
        pbuffer[dst_index] = lsb;
        --src_index;
 
        // Now do the shifting.
        while (src_index >= 0)
        {
          // Shift msb.
          element_type msb   = element_type((pbuffer[src_index] & msb_mask) >> msb_shift);
          pbuffer[dst_index] = pbuffer[dst_index] | msb;
          --dst_index;
 
          // Shift lsb.
          lsb                = element_type((pbuffer[src_index] & lsb_mask) << lsb_shift);
          pbuffer[dst_index] = lsb;
          --src_index;
        }
 
        // Clear the remaining bits.
        // First lsb.
        pbuffer[dst_index] &= lsb_shifted_mask;
 
        // The other remaining bytes on the right.
        for (int i = 0; i < dst_index; ++i)
        {
          pbuffer[i] = 0;
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void operator_shift_right(pointer pbuffer, size_t number_of_elements, size_t active_bits, size_t shift) ETL_NOEXCEPT
    {
      if (shift >= active_bits)
      {
        reset_all(pbuffer, number_of_elements);
      }
      else
      {
        // The place where the elements are split when shifting.
        const size_t split_position = shift % Bits_Per_Element;
 
        // Where we are shifting from.
        int src_index = int(shift / Bits_Per_Element);
 
        // Where we are shifting to.
        int dst_index = 0;
 
        // Shift control constants.
        const size_t lsb_shift = Bits_Per_Element - split_position;
        const size_t msb_shift = split_position;
 
        const element_type lsb_mask         = element_type(etl::integral_limits<element_type>::max >> (Bits_Per_Element - split_position));
        const element_type msb_mask         = etl::integral_limits<element_type>::max - lsb_mask;
        const element_type msb_shifted_mask = element_type(msb_mask >> msb_shift);
 
        // Now do the shifting.
        while (src_index < int(number_of_elements - 1))
        {
          // Shift msb.
          element_type msb = element_type((pbuffer[src_index] & msb_mask) >> msb_shift);
          ++src_index;
 
          // Shift lsb.
          element_type lsb = element_type((pbuffer[src_index] & lsb_mask) << lsb_shift);
 
          // Combine them.
          pbuffer[dst_index] = lsb | msb;
          ++dst_index;
        }
 
        // Final msb.
        element_type msb   = element_type((pbuffer[src_index] & msb_mask) >> msb_shift);
        pbuffer[dst_index] = msb;
 
        // Clear the remaining bits.
        // First msb.
        pbuffer[dst_index] &= msb_shifted_mask;
        ++dst_index;
 
        // The other remaining bytes.
        while (dst_index < int(number_of_elements))
        {
          pbuffer[dst_index] = 0;
          ++dst_index;
        }
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 bool operator_equality(const_pointer lhs_pbuffer, const_pointer rhs_pbuffer, size_t number_of_elements) ETL_NOEXCEPT
    {
      return etl::equal(lhs_pbuffer, lhs_pbuffer + number_of_elements, rhs_pbuffer);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TElementType>
    static
      ETL_CONSTEXPR14 typename etl::enable_if< etl::integral_limits<TElementType>::bits == etl::integral_limits<unsigned long long>::bits, void>::type
      initialise(pointer pbuffer, size_t number_of_elements, unsigned long long value) ETL_NOEXCEPT
    {
      size_t i = 0UL;
 
      // Set the non-zero elements.
      pbuffer[i++] = value;
 
      // Clear the remaining elements.
      while (i != number_of_elements)
      {
        pbuffer[i++] = All_Clear_Element;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TElementType>
    static
      ETL_CONSTEXPR14 typename etl::enable_if< etl::integral_limits<TElementType>::bits != etl::integral_limits<unsigned long long>::bits, void>::type
      initialise(pointer pbuffer, size_t number_of_elements, unsigned long long value) ETL_NOEXCEPT
    {
      size_t i = 0UL;
 
      // Set the non-zero elements.
      const unsigned long long Shift = etl::integral_limits<element_type>::bits;
 
      while ((value != 0) && (i != number_of_elements))
      {
        pbuffer[i++] = value & All_Set_Element;
        value        = value >> Shift;
      }
 
      // Clear the remaining elements.
      while (i != number_of_elements)
      {
        pbuffer[i++] = All_Clear_Element;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR14 void swap(pointer pbuffer1, pointer pbuffer2, size_t number_of_elements)
    {
      etl::swap_ranges(pbuffer1, pbuffer1 + number_of_elements, pbuffer2);
    }
  };
 
  namespace private_bitset
  {
    //***************************************************************************
    template <size_t Active_Bits, typename TElement>
    class bitset_common : public etl::private_bitset::bitset_impl_common<TElement>
    {
    public:
 
      typedef typename etl::private_bitset::bitset_impl_common<TElement>::element_type element_type;
 
      using etl::private_bitset::bitset_impl_common<TElement>::Bits_Per_Element;
      using etl::private_bitset::bitset_impl_common<TElement>::All_Set_Element;
      using etl::private_bitset::bitset_impl_common< TElement>::All_Clear_Element;
 
      static ETL_CONSTANT size_t Number_Of_Elements =
        (Active_Bits % Bits_Per_Element == 0) ? Active_Bits / Bits_Per_Element : Active_Bits / Bits_Per_Element + 1;
      static ETL_CONSTANT size_t Size           = Active_Bits;
      static ETL_CONSTANT size_t Allocated_Bits = Number_Of_Elements * Bits_Per_Element;
 
#if ETL_USING_CPP11
      static ETL_CONSTANT etl::bitset_storage_model Storage_Model =
        (bitset_common<Active_Bits, TElement>::Number_Of_Elements == 1U) ? etl::bitset_storage_model::Single : etl::bitset_storage_model::Multi;
#else
      static ETL_CONSTANT etl::bitset_storage_model Storage_Model;
#endif
 
      typedef etl::span<element_type, Number_Of_Elements>       span_type;
      typedef etl::span<const element_type, Number_Of_Elements> const_span_type;
 
    private:
 
      static ETL_CONSTANT size_t Top_Mask_Shift = ((Bits_Per_Element - ((Number_Of_Elements * Bits_Per_Element) - Active_Bits)) % Bits_Per_Element);
 
    public:
 
      static ETL_CONSTANT TElement Top_Mask = element_type(Top_Mask_Shift == 0 ? All_Set_Element : ~(All_Set_Element << Top_Mask_Shift));
    };
 
    template <size_t Active_Bits, typename TElement>
    ETL_CONSTANT size_t bitset_common<Active_Bits, TElement>::Number_Of_Elements;
 
    template <size_t Active_Bits, typename TElement>
    ETL_CONSTANT size_t bitset_common<Active_Bits, TElement>::Size;
 
#if ETL_USING_CPP11
    template <size_t Active_Bits, typename TElement>
    ETL_CONSTANT etl::bitset_storage_model bitset_common<Active_Bits, TElement>::Storage_Model;
#else
    template <size_t Active_Bits, typename TElement>
    ETL_CONSTANT etl::bitset_storage_model bitset_common<Active_Bits, TElement>::Storage_Model =
      (bitset_common<Active_Bits, TElement>::Number_Of_Elements == 1U) ? etl::bitset_storage_model::Single : etl::bitset_storage_model::Multi;
#endif
 
    template <size_t Active_Bits, typename TElement>
    ETL_CONSTANT size_t bitset_common<Active_Bits, TElement>::Top_Mask_Shift;
 
    template <size_t Active_Bits, typename TElement>
    ETL_CONSTANT TElement bitset_common<Active_Bits, TElement>::Top_Mask;
  } // namespace private_bitset
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits = 0U, typename TElement = unsigned char>
  class bitset;
 
  //***************************************************************************
  //***************************************************************************
  template <>
  class bitset<0U, unsigned char> : public etl::private_bitset::bitset_common<0U, unsigned char>
  {
  public:
 
    typedef etl::private_bitset::bitset_common<0U, unsigned char>::element_type     element_type;
    typedef etl::private_bitset::bitset_common<0U, unsigned char>::span_type        span_type;
    typedef etl::private_bitset::bitset_common< 0U, unsigned char>::const_span_type const_span_type;
 
    using etl::private_bitset::bitset_common<0U, unsigned char>::Bits_Per_Element;
    using etl::private_bitset::bitset_common<0U, unsigned char>::All_Set_Element;
    using etl::private_bitset::bitset_common<0U, unsigned char>::All_Clear_Element;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Number_Of_Elements;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Size;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Storage_Model;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Top_Mask;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Allocated_Bits;
  };
 
  //*************************************************************************
  //*************************************************************************
  template <size_t Active_Bits, typename TElement>
  class bitset : public etl::private_bitset::bitset_common<Active_Bits, TElement>
  {
  public:
 
    ETL_STATIC_ASSERT(etl::is_unsigned<TElement>::value, "The element type must be unsigned");
 
    typedef typename etl::private_bitset::bitset_common< Active_Bits, TElement>::element_type    element_type;
    typedef typename etl::private_bitset::bitset_common< Active_Bits, TElement>::span_type       span_type;
    typedef typename etl::private_bitset::bitset_common< Active_Bits, TElement>::const_span_type const_span_type;
 
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Bits_Per_Element;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::All_Set_Element;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::All_Clear_Element;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Number_Of_Elements;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Size;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Storage_Model;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Top_Mask;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Allocated_Bits;
 
    //*************************************************************************
    //*************************************************************************
    class bit_reference
    {
    public:
 
      friend class bitset;
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference(const bit_reference& other) ETL_NOEXCEPT
        : p_bitset(other.p_bitset)
        , position(other.position)
      {
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 operator bool() const ETL_NOEXCEPT
      {
        return p_bitset->test(position);
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference& operator=(bool b) ETL_NOEXCEPT
      {
        p_bitset->set(position, b);
        return *this;
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference& operator=(const bit_reference& r) ETL_NOEXCEPT
      {
        p_bitset->set(position, bool(r));
        return *this;
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference& flip() ETL_NOEXCEPT
      {
        p_bitset->flip(position);
        return *this;
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bool operator~() const ETL_NOEXCEPT
      {
        return !p_bitset->test(position);
      }
 
    private:
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference() ETL_NOEXCEPT
        : p_bitset(ETL_NULLPTR)
        , position(0)
      {
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference(bitset<Active_Bits, TElement>& r_bitset, size_t position_) ETL_NOEXCEPT
        : p_bitset(&r_bitset)
        , position(position_)
      {
      }
 
      bitset<Active_Bits, TElement>* p_bitset; 
      size_t                         position; 
    };
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset() ETL_NOEXCEPT
      : buffer()
    {
      implementation::reset_all(buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset(const bitset<Active_Bits, TElement>& other) ETL_NOEXCEPT
      : buffer()
    {
      implementation::operator_assignment(buffer, other.buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TValue>
    ETL_CONSTEXPR14 bitset(TValue value, typename etl::enable_if<is_integral<TValue>::value>::type* = 0) ETL_NOEXCEPT
      : buffer()
    {
      implementation::template initialise<element_type>(buffer, Number_Of_Elements, static_cast<unsigned long long>(value));
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset(TPString text, typename etl::enable_if<is_same<TPString, const char*>::value>::type* = 0) ETL_NOEXCEPT
      : buffer()
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset(TPString text, typename etl::enable_if<is_same<TPString, const wchar_t*>::value>::type* = 0) ETL_NOEXCEPT
      : buffer()
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset(TPString text, typename etl::enable_if< is_same<TPString, const char16_t*>::value>::type* = 0) ETL_NOEXCEPT
      : buffer()
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset(TPString text, typename etl::enable_if< is_same<TPString, const char32_t*>::value>::type* = 0) ETL_NOEXCEPT
      : buffer()
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset& operator=(const bitset<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::operator_assignment(buffer, other.buffer, Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& set() ETL_NOEXCEPT
    {
      implementation::set_all(buffer, Number_Of_Elements, Top_Mask);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& set(size_t position, bool value = true)
    {
      ETL_ASSERT_OR_RETURN_VALUE(position < Active_Bits, ETL_ERROR(bitset_overflow), *this);
 
      implementation::set_position(buffer, position, value);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position>
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& set(bool value = true)
    {
      ETL_STATIC_ASSERT(Position < Active_Bits, "Position out of bounds");
 
      implementation::template set_position<Position>(buffer, value);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position, bool Value>
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& set()
    {
      ETL_STATIC_ASSERT(Position < Active_Bits, "Position out of bounds");
 
      implementation::template set_position<Position, Value>(buffer);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_same<TPString, const char*>::value, bitset<Active_Bits, TElement>&>::type set(TPString text)
      ETL_NOEXCEPT
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_same<TPString, const wchar_t*>::value, bitset<Active_Bits, TElement>&>::type set(TPString text)
      ETL_NOEXCEPT
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_same<TPString, const char16_t*>::value, bitset<Active_Bits, TElement>&>::type set(TPString text)
      ETL_NOEXCEPT
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_same<TPString, const char32_t*>::value, bitset<Active_Bits, TElement>&>::type set(TPString text)
      ETL_NOEXCEPT
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& from_string(const char* text) ETL_NOEXCEPT
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& from_string(const wchar_t* text) ETL_NOEXCEPT
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& from_string(const char16_t* text) ETL_NOEXCEPT
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& from_string(const char32_t* text) ETL_NOEXCEPT
    {
      implementation::from_string(buffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_integral<T>::value, T>::type value() const ETL_NOEXCEPT
    {
      ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Only integral types are supported");
      ETL_STATIC_ASSERT(etl::integral_limits<T>::bits >= (Number_Of_Elements * Bits_Per_Element), "Type too small");
 
      return implementation::template value<T>(buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    ETL_CONSTEXPR14 T extract(size_t position, size_t length = etl::integral_limits<T>::bits) const
    {
      ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Only integral types are supported");
 
      ETL_ASSERT_OR_RETURN_VALUE(length <= etl::integral_limits<T>::bits, ETL_ERROR(bitset_overflow), 0);
      ETL_ASSERT_OR_RETURN_VALUE((position + length) <= Active_Bits, ETL_ERROR(bitset_overflow), 0);
 
      return implementation::template extract<T>(buffer, position, length);
    }
 
    //*************************************************************************
    //*************************************************************************
#if ETL_USING_CPP11
    template <typename T, size_t Position, size_t Length = etl::integral_limits<T>::bits>
#else
    template <typename T, size_t Position, size_t Length>
#endif
    ETL_CONSTEXPR14 T extract() const
    {
      ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Only integral types are supported");
      ETL_STATIC_ASSERT(Length <= etl::integral_limits<T>::bits, "Length is larger that the required type");
      ETL_STATIC_ASSERT((Position + Length) <= Active_Bits, "Position/Length overflows bitset");
 
      return implementation::template extract<T, Position, Length>(buffer);
    }
 
    //*************************************************************************
    //*************************************************************************
    unsigned long to_ulong() const
    {
      ETL_ASSERT(etl::integral_limits<unsigned long>::bits >= Active_Bits, ETL_ERROR(etl::bitset_overflow));
 
      return implementation::template value<unsigned long>(buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    unsigned long long to_ullong() const
    {
      ETL_ASSERT(etl::integral_limits<unsigned long long>::bits >= Active_Bits, ETL_ERROR(etl::bitset_overflow));
 
      return implementation::template value<unsigned long long>(buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& reset() ETL_NOEXCEPT
    {
      implementation::reset_all(buffer, Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& reset(size_t position)
    {
      ETL_ASSERT_OR_RETURN_VALUE(position < Active_Bits, ETL_ERROR(bitset_overflow), *this);
 
      implementation::reset_position(buffer, position);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool test(size_t position) const
    {
      ETL_ASSERT_OR_RETURN_VALUE(position < Active_Bits, ETL_ERROR(bitset_overflow), false);
 
      return implementation::test(buffer, position);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position>
    ETL_CONSTEXPR14 bool test() const
    {
      ETL_STATIC_ASSERT(Position < Active_Bits, "Position out of bounds");
 
      return implementation::test(buffer, Position);
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR size_t size() ETL_NOEXCEPT
    {
      return Active_Bits;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR size_t number_of_elements() ETL_NOEXCEPT
    {
      return Number_Of_Elements;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR element_type all_set_element() ETL_NOEXCEPT
    {
      return All_Set_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR element_type all_clear_element() ETL_NOEXCEPT
    {
      return All_Clear_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR size_t bits_per_element() ETL_NOEXCEPT
    {
      return Bits_Per_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR element_type top_mask() ETL_NOEXCEPT
    {
      return Top_Mask;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR size_t allocated_bits() ETL_NOEXCEPT
    {
      return Number_Of_Elements * Bits_Per_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR etl::bitset_storage_model storage_model() ETL_NOEXCEPT
    {
      return Storage_Model;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t count() const ETL_NOEXCEPT
    {
      return implementation::count(buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    // Are all the bits sets?
    //*************************************************************************
    ETL_CONSTEXPR14 bool all() const ETL_NOEXCEPT
    {
      return implementation::all(buffer, Number_Of_Elements, Top_Mask);
    }
 
    //*************************************************************************
    // Are all the mask bits sets?
    //*************************************************************************
    ETL_CONSTEXPR14 bool all(element_type mask) const ETL_NOEXCEPT
    {
      ETL_STATIC_ASSERT(Storage_Model == etl::bitset_storage_model::Single, "Not supported for 'Multi' bitset storage model");
 
      return implementation::all(buffer, Number_Of_Elements, Top_Mask, mask);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool none() const ETL_NOEXCEPT
    {
      return implementation::none(buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool none(element_type mask) const ETL_NOEXCEPT
    {
      ETL_STATIC_ASSERT(Storage_Model == etl::bitset_storage_model::Single, "Not supported for 'Multi' bitset storage model");
 
      return implementation::none(buffer, Number_Of_Elements, mask);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool any() const ETL_NOEXCEPT
    {
      return implementation::any(buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool any(element_type mask) const ETL_NOEXCEPT
    {
      ETL_STATIC_ASSERT(Storage_Model == etl::bitset_storage_model::Single, "Not supported for 'Multi' bitset storage model");
 
      return implementation::any(buffer, Number_Of_Elements, mask);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& flip() ETL_NOEXCEPT
    {
      implementation::flip_all(buffer, Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& flip(size_t position)
    {
      ETL_ASSERT_OR_RETURN_VALUE(position < Active_Bits, ETL_ERROR(bitset_overflow), *this);
 
      implementation::flip_position(buffer, position);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool operator[](size_t position) const ETL_NOEXCEPT
    {
      return implementation::test(buffer, position);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bit_reference operator[](size_t position) ETL_NOEXCEPT
    {
      return bit_reference(*this, position);
    }
 
    //*************************************************************************
    //*************************************************************************
#if ETL_USING_CPP11
    template <typename TString = etl::string<Active_Bits>>
#else
    template <typename TString>
#endif
    ETL_CONSTEXPR14 TString to_string(typename TString::value_type zero = typename TString::value_type('0'),
                                typename TString::value_type one  = typename TString::value_type('1')) const
    {
      return implementation::template to_string<TString>(buffer, Active_Bits, zero, one);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t find_first(bool state) const ETL_NOEXCEPT
    {
      return implementation::find_next(buffer, Number_Of_Elements, Active_Bits, state, 0);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t find_next(bool state, size_t position) const ETL_NOEXCEPT
    {
      return implementation::find_next(buffer, Number_Of_Elements, Active_Bits, state, position);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement> operator&(const bitset<Active_Bits, TElement>& other) const ETL_NOEXCEPT
    {
      etl::bitset<Active_Bits, TElement> temp(*this);
 
      implementation::operator_and(temp.buffer, other.buffer, Number_Of_Elements);
 
      return temp;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& operator&=(const bitset<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::operator_and(buffer, other.buffer, Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement> operator|(const bitset<Active_Bits, TElement>& other) const ETL_NOEXCEPT
    {
      etl::bitset<Active_Bits, TElement> temp(*this);
 
      implementation::operator_or(temp.buffer, other.buffer, Number_Of_Elements);
 
      return temp;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& operator|=(const bitset<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::operator_or(&buffer[0], &other.buffer[0], Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement> operator^(const bitset<Active_Bits, TElement>& other) const ETL_NOEXCEPT
    {
      etl::bitset<Active_Bits, TElement> temp(*this);
 
      implementation::operator_xor(temp.buffer, other.buffer, Number_Of_Elements);
 
      return temp;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& operator^=(const bitset<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::operator_xor(buffer, other.buffer, Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement> operator~() const ETL_NOEXCEPT
    {
      etl::bitset<Active_Bits, TElement> temp(*this);
 
      implementation::flip_all(temp.buffer, Number_Of_Elements);
 
      return temp;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement> operator<<(size_t shift) const ETL_NOEXCEPT
    {
      etl::bitset<Active_Bits, TElement> temp(*this);
 
      implementation::operator_shift_left(temp.buffer, Number_Of_Elements, Active_Bits, shift);
 
      return temp;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& operator<<=(size_t shift) ETL_NOEXCEPT
    {
      if (shift >= Active_Bits)
      {
        implementation::reset_all(buffer, Number_Of_Elements);
      }
      else
      {
        implementation::operator_shift_left(buffer, Number_Of_Elements, Active_Bits, shift);
      }
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement> operator>>(size_t shift) const ETL_NOEXCEPT
    {
      bitset<Active_Bits, TElement> temp(*this);
 
      implementation::operator_shift_right(temp.buffer, Number_Of_Elements, Active_Bits, shift);
 
      return temp;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset<Active_Bits, TElement>& operator>>=(size_t shift) ETL_NOEXCEPT
    {
      if (shift >= Active_Bits)
      {
        implementation::reset_all(buffer, Number_Of_Elements);
      }
      else
      {
        implementation::operator_shift_right(buffer, Number_Of_Elements, Active_Bits, shift);
      }
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    friend ETL_CONSTEXPR14 bool operator==(const bitset<Active_Bits, TElement>& lhs, const bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
    {
      return implementation::operator_equality(lhs.buffer, rhs.buffer, lhs.Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    friend ETL_CONSTEXPR14 bool operator!=(const bitset<Active_Bits, TElement>& lhs, const bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
    {
      return !(lhs == rhs);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 void swap(etl::bitset<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::swap(buffer, other.buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 span_type span() ETL_NOEXCEPT
    {
      return span_type(buffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 const_span_type span() const ETL_NOEXCEPT
    {
      return const_span_type(buffer, Number_Of_Elements);
    }
 
  private:
 
    // The implementation of the bitset functionality.
    typedef etl::bitset_impl<element_type, (Number_Of_Elements == 1U) ? etl::bitset_storage_model::Single : etl::bitset_storage_model::Multi>
      implementation;
 
    // The storage for the bitset.
    element_type buffer[Number_Of_Elements];
  };
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bitset<Active_Bits> operator&(const bitset<Active_Bits, TElement>& lhs, const bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    bitset<Active_Bits> temp(lhs);
    temp &= rhs;
    return temp;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bitset<Active_Bits> operator|(const bitset<Active_Bits, TElement>& lhs, const bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    bitset<Active_Bits> temp(lhs);
    temp |= rhs;
    return temp;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bitset<Active_Bits> operator^(const bitset<Active_Bits, TElement>& lhs, const bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    bitset<Active_Bits> temp(lhs);
    temp ^= rhs;
    return temp;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bool operator!=(const etl::bitset<Active_Bits, TElement>& lhs, const etl::bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    return !(lhs == rhs);
  }
 
  //*************************************************************************
  //*************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 void swap(etl::bitset<Active_Bits, TElement>& lhs, etl::bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    lhs.swap(rhs);
  }
 
  //***************************************************************************
  //***************************************************************************
 
  //***************************************************************************
  template <size_t Active_Bits = 0U, typename TElement = unsigned char>
  class bitset_ext;
 
  //***************************************************************************
  //***************************************************************************
  template <>
  class bitset_ext<0U, unsigned char> : public etl::private_bitset::bitset_common<0U, unsigned char>
  {
  public:
 
    typedef size_t size_type;
 
    typedef etl::private_bitset::bitset_common<0U, unsigned char>::element_type     element_type;
    typedef etl::private_bitset::bitset_common<0U, unsigned char>::span_type        span_type;
    typedef etl::private_bitset::bitset_common< 0U, unsigned char>::const_span_type const_span_type;
 
    using etl::private_bitset::bitset_common<0U, unsigned char>::Bits_Per_Element;
    using etl::private_bitset::bitset_common<0U, unsigned char>::All_Set_Element;
    using etl::private_bitset::bitset_common<0U, unsigned char>::All_Clear_Element;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Number_Of_Elements;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Size;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Storage_Model;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Top_Mask;
    using etl::private_bitset::bitset_common<0U, unsigned char>::Allocated_Bits;
  };
 
  //*************************************************************************
  //*************************************************************************
  template <size_t Active_Bits, typename TElement>
  class bitset_ext : public etl::private_bitset::bitset_common<Active_Bits, TElement>
  {
  public:
 
    ETL_STATIC_ASSERT(etl::is_unsigned<TElement>::value, "The element type must be unsigned");
 
    typedef size_t size_type;
 
    typedef typename etl::private_bitset::bitset_common< Active_Bits, TElement>::element_type    element_type;
    typedef typename etl::private_bitset::bitset_common< Active_Bits, TElement>::span_type       span_type;
    typedef typename etl::private_bitset::bitset_common< Active_Bits, TElement>::const_span_type const_span_type;
 
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Bits_Per_Element;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::All_Set_Element;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::All_Clear_Element;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Number_Of_Elements;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Size;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Storage_Model;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Top_Mask;
    using etl::private_bitset::bitset_common<Active_Bits, TElement>::Allocated_Bits;
 
    typedef etl::array<TElement, Number_Of_Elements> buffer_type;
 
    //*************************************************************************
    //*************************************************************************
    class bit_reference
    {
    public:
 
      friend class bitset_ext;
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference(const bit_reference& other) ETL_NOEXCEPT
        : p_bitset(other.p_bitset)
        , position(other.position)
      {
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 operator bool() const ETL_NOEXCEPT
      {
        return p_bitset->test(position);
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference& operator=(bool b) ETL_NOEXCEPT
      {
        p_bitset->set(position, b);
        return *this;
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference& operator=(const bit_reference& r) ETL_NOEXCEPT
      {
        p_bitset->set(position, bool(r));
        return *this;
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference& flip() ETL_NOEXCEPT
      {
        p_bitset->flip(position);
        return *this;
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bool operator~() const ETL_NOEXCEPT
      {
        return !p_bitset->test(position);
      }
 
    private:
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference() ETL_NOEXCEPT
        : p_bitset(ETL_NULLPTR)
        , position(0)
      {
      }
 
      //*******************************
      //*******************************
      ETL_CONSTEXPR14 bit_reference(bitset_ext<Active_Bits, TElement>& r_bitset, size_t position_) ETL_NOEXCEPT
        : p_bitset(&r_bitset)
        , position(position_)
      {
      }
 
      bitset_ext<Active_Bits, TElement>* p_bitset; 
      size_t                             position; 
    };
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 explicit bitset_ext(element_type* pbuffer_)
      : pbuffer(pbuffer_)
    {
      ETL_ASSERT(pbuffer != ETL_NULLPTR, ETL_ERROR(etl::bitset_invalid_buffer));
      implementation::reset_all(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 explicit bitset_ext(buffer_type& buffer)
      : pbuffer(buffer.data())
    {
      ETL_ASSERT(pbuffer != ETL_NULLPTR, ETL_ERROR(etl::bitset_invalid_buffer));
      implementation::reset_all(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext(const bitset_ext<Active_Bits, TElement>& other, element_type* pbuffer_)
      : pbuffer(pbuffer_)
    {
      ETL_ASSERT(pbuffer != ETL_NULLPTR, ETL_ERROR(etl::bitset_invalid_buffer));
      implementation::operator_assignment(pbuffer, other.pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext(const bitset_ext<Active_Bits, TElement>& other, buffer_type& buffer) ETL_NOEXCEPT
      : pbuffer(buffer.data())
    {
      implementation::operator_assignment(pbuffer, other.pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext(const bitset_ext<Active_Bits, TElement>& other) ETL_NOEXCEPT ETL_DELETE;
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext(unsigned long long value, element_type* pbuffer_)
      : pbuffer(pbuffer_)
    {
      ETL_ASSERT(pbuffer != ETL_NULLPTR, ETL_ERROR(etl::bitset_invalid_buffer));
      implementation::template initialise<element_type>(pbuffer, Number_Of_Elements, value);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TValue>
    ETL_CONSTEXPR14 bitset_ext(TValue value, buffer_type& buffer, typename etl::enable_if<is_integral<TValue>::value>::type* = 0) ETL_NOEXCEPT
      : pbuffer(buffer.data())
    {
      implementation::template initialise<element_type>(pbuffer, Number_Of_Elements, static_cast<unsigned long long>(value));
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset_ext(TPString text, element_type* pbuffer_, typename etl::enable_if<is_same<TPString, const char*>::value>::type* = 0)
      : pbuffer(pbuffer_)
    {
      ETL_ASSERT(pbuffer != ETL_NULLPTR, ETL_ERROR(etl::bitset_invalid_buffer));
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset_ext(TPString text, buffer_type& buffer, typename etl::enable_if<is_same<TPString, const char*>::value>::type* = 0)
      ETL_NOEXCEPT
      : pbuffer(buffer.data())
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset_ext(TPString text, element_type* pbuffer_, typename etl::enable_if<is_same<TPString, const wchar_t*>::value>::type* = 0)
      : pbuffer(pbuffer_)
    {
      ETL_ASSERT(pbuffer != ETL_NULLPTR, ETL_ERROR(etl::bitset_invalid_buffer));
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset_ext(TPString text, buffer_type& buffer, typename etl::enable_if<is_same<TPString, const wchar_t*>::value>::type* = 0)
      ETL_NOEXCEPT
      : pbuffer(buffer.data())
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset_ext(TPString text, element_type* pbuffer_, typename etl::enable_if< is_same<TPString, const char16_t*>::value>::type* = 0)
      : pbuffer(pbuffer_)
    {
      ETL_ASSERT(pbuffer != ETL_NULLPTR, ETL_ERROR(etl::bitset_invalid_buffer));
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset_ext(TPString text, buffer_type& buffer, typename etl::enable_if< is_same<TPString, const char16_t*>::value>::type* = 0)
      ETL_NOEXCEPT
      : pbuffer(buffer.data())
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset_ext(TPString text, element_type* pbuffer_, typename etl::enable_if< is_same<TPString, const char32_t*>::value>::type* = 0)
      : pbuffer(pbuffer_)
    {
      ETL_ASSERT(pbuffer != ETL_NULLPTR, ETL_ERROR(etl::bitset_invalid_buffer));
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 bitset_ext(TPString text, buffer_type& buffer, typename etl::enable_if< is_same<TPString, const char32_t*>::value>::type* = 0)
      ETL_NOEXCEPT
      : pbuffer(buffer.data())
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext& operator=(const bitset_ext<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::operator_assignment(pbuffer, other.pbuffer, Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& set() ETL_NOEXCEPT
    {
      implementation::set_all(pbuffer, Number_Of_Elements, Top_Mask);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& set(size_t position, bool value = true)
    {
      ETL_ASSERT_OR_RETURN_VALUE(position < Active_Bits, ETL_ERROR(bitset_overflow), *this);
 
      implementation::set_position(pbuffer, position, value);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position>
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& set(bool value = true)
    {
      ETL_STATIC_ASSERT(Position < Active_Bits, "Position out of bounds");
 
      implementation::template set_position<Position>(pbuffer, value);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position, bool Value>
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& set()
    {
      ETL_STATIC_ASSERT(Position < Active_Bits, "Position out of bounds");
 
      implementation::template set_position<Position, Value>(pbuffer);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_same<TPString, const char*>::value, bitset_ext<Active_Bits, TElement>&>::type set(TPString text)
      ETL_NOEXCEPT
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_same<TPString, const wchar_t*>::value, bitset_ext<Active_Bits, TElement>&>::type
      set(TPString text) ETL_NOEXCEPT
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_same<TPString, const char16_t*>::value, bitset_ext<Active_Bits, TElement>&>::type
      set(TPString text) ETL_NOEXCEPT
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TPString>
    ETL_CONSTEXPR14 typename etl::enable_if<etl::is_same<TPString, const char32_t*>::value, bitset_ext<Active_Bits, TElement>&>::type
      set(TPString text) ETL_NOEXCEPT
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& from_string(const char* text) ETL_NOEXCEPT
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& from_string(const wchar_t* text) ETL_NOEXCEPT
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& from_string(const char16_t* text) ETL_NOEXCEPT
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& from_string(const char32_t* text) ETL_NOEXCEPT
    {
      implementation::from_string(pbuffer, Number_Of_Elements, Active_Bits, text);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    ETL_CONSTEXPR14 T value() const ETL_NOEXCEPT
    {
      ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Only integral types are supported");
      ETL_STATIC_ASSERT(etl::integral_limits<T>::bits >= (Number_Of_Elements * Bits_Per_Element), "Type too small");
 
      return implementation::template value<T>(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename T>
    ETL_CONSTEXPR14 T extract(size_t position, size_t length = etl::integral_limits<T>::bits)
    {
      ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Only integral types are supported");
 
      ETL_ASSERT_OR_RETURN_VALUE(length <= etl::integral_limits<T>::bits, ETL_ERROR(bitset_overflow), 0);
      ETL_ASSERT_OR_RETURN_VALUE((position + length) <= Active_Bits, ETL_ERROR(bitset_overflow), 0);
 
      return implementation::template extract<T>(pbuffer, position, length);
    }
 
    //*************************************************************************
    //*************************************************************************
#if ETL_USING_CPP11
    template <typename T, size_t Position, size_t Length = etl::integral_limits<T>::bits>
#else
    template <typename T, size_t Position, size_t Length>
#endif
    ETL_CONSTEXPR14 T extract() const
    {
      ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Only integral types are supported");
      ETL_STATIC_ASSERT(Length <= etl::integral_limits<T>::bits, "Length is larger that the required type");
      ETL_STATIC_ASSERT((Position + Length) <= Active_Bits, "Position/Length overflows bitset");
 
      return implementation::template extract<T, Position, Length>(pbuffer);
    }
 
    //*************************************************************************
    //*************************************************************************
    unsigned long to_ulong() const
    {
      ETL_ASSERT(etl::integral_limits<unsigned long>::bits >= Active_Bits, ETL_ERROR(etl::bitset_overflow));
 
      return implementation::template value<unsigned long>(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    unsigned long long to_ullong() const
    {
      ETL_ASSERT(etl::integral_limits<unsigned long long>::bits >= Active_Bits, ETL_ERROR(etl::bitset_overflow));
 
      return implementation::template value<unsigned long long>(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& reset() ETL_NOEXCEPT
    {
      implementation::reset_all(pbuffer, Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& reset(size_t position)
    {
      ETL_ASSERT_OR_RETURN_VALUE(position < Active_Bits, ETL_ERROR(bitset_overflow), *this);
 
      implementation::reset_position(pbuffer, position);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool test(size_t position) const
    {
      ETL_ASSERT_OR_RETURN_VALUE(position < Active_Bits, ETL_ERROR(bitset_overflow), false);
 
      return implementation::test(pbuffer, position);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <size_t Position>
    ETL_CONSTEXPR14 bool test() const
    {
      ETL_STATIC_ASSERT(Position < Active_Bits, "Position out of bounds");
 
      return implementation::test(pbuffer, Position);
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR size_t size() ETL_NOEXCEPT
    {
      return Active_Bits;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR size_t number_of_elements() ETL_NOEXCEPT
    {
      return Number_Of_Elements;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR element_type all_set_element() ETL_NOEXCEPT
    {
      return All_Set_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR element_type all_clear_element() ETL_NOEXCEPT
    {
      return All_Clear_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR element_type top_mask() ETL_NOEXCEPT
    {
      return Top_Mask;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR size_t bits_per_element() ETL_NOEXCEPT
    {
      return Bits_Per_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR size_t allocated_bits() ETL_NOEXCEPT
    {
      return Number_Of_Elements * Bits_Per_Element;
    }
 
    //*************************************************************************
    //*************************************************************************
    static ETL_CONSTEXPR etl::bitset_storage_model storage_model() ETL_NOEXCEPT
    {
      return Storage_Model;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t count() const ETL_NOEXCEPT
    {
      return implementation::count(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    // Are all the bits sets?
    //*************************************************************************
    ETL_CONSTEXPR14 bool all() const ETL_NOEXCEPT
    {
      return implementation::all(pbuffer, Number_Of_Elements, Top_Mask);
    }
 
    //*************************************************************************
    // Are all the mask bits sets?
    //*************************************************************************
    ETL_CONSTEXPR14 bool all(element_type mask) const ETL_NOEXCEPT
    {
      ETL_STATIC_ASSERT(Storage_Model == etl::bitset_storage_model::Single, "Not supported for 'Multi' bitset storage model");
 
      return implementation::all(pbuffer, Number_Of_Elements, Top_Mask, mask);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool none() const ETL_NOEXCEPT
    {
      return implementation::none(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool none(element_type mask) const ETL_NOEXCEPT
    {
      ETL_STATIC_ASSERT(Storage_Model == etl::bitset_storage_model::Single, "Not supported for 'Multi' bitset storage model");
 
      return implementation::none(pbuffer, Number_Of_Elements, mask);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool any() const ETL_NOEXCEPT
    {
      return implementation::any(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool any(element_type mask) const ETL_NOEXCEPT
    {
      ETL_STATIC_ASSERT(Storage_Model == etl::bitset_storage_model::Single, "Not supported for 'Multi' bitset storage model");
 
      return implementation::any(pbuffer, Number_Of_Elements, mask);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& flip() ETL_NOEXCEPT
    {
      implementation::flip_all(pbuffer, Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& flip(size_t position)
    {
      ETL_ASSERT_OR_RETURN_VALUE(position < Active_Bits, ETL_ERROR(bitset_overflow), *this);
 
      implementation::flip_position(pbuffer, position);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool operator[](size_t position) const ETL_NOEXCEPT
    {
      return implementation::test(pbuffer, position);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bit_reference operator[](size_t position) ETL_NOEXCEPT
    {
      return bit_reference(*this, position);
    }
 
    //*************************************************************************
    //*************************************************************************
#if ETL_USING_CPP11
    template <typename TString = etl::string<Active_Bits>>
#else
    template <typename TString>
#endif
    ETL_CONSTEXPR14 TString to_string(typename TString::value_type zero = typename TString::value_type('0'),
                                typename TString::value_type one  = typename TString::value_type('1')) const
    {
      return implementation::template to_string<TString>(pbuffer, Active_Bits, zero, one);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t find_first(bool state) const ETL_NOEXCEPT
    {
      return implementation::find_next(pbuffer, Number_Of_Elements, Active_Bits, state, 0);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t find_next(bool state, size_t position) const ETL_NOEXCEPT
    {
      return implementation::find_next(pbuffer, Number_Of_Elements, Active_Bits, state, position);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& operator&=(const bitset_ext<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::operator_and(&pbuffer[0], &other.pbuffer[0], Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& operator|=(const bitset_ext<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::operator_or(&pbuffer[0], &other.pbuffer[0], Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& operator^=(const bitset_ext<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::operator_xor(&pbuffer[0], &other.pbuffer[0], Number_Of_Elements);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& operator<<=(size_t shift) ETL_NOEXCEPT
    {
      implementation::operator_shift_left(pbuffer, Number_Of_Elements, Active_Bits, shift);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bitset_ext<Active_Bits, TElement>& operator>>=(size_t shift) ETL_NOEXCEPT
    {
      implementation::operator_shift_right(pbuffer, Number_Of_Elements, Active_Bits, shift);
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    friend ETL_CONSTEXPR14 bool operator==(const bitset_ext<Active_Bits, TElement>& lhs, const bitset_ext<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
    {
      return implementation::operator_equality(lhs.pbuffer, rhs.pbuffer, lhs.Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    friend ETL_CONSTEXPR14 bool operator!=(const bitset_ext<Active_Bits, TElement>& lhs, const bitset_ext<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
    {
      return !(lhs == rhs);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 void swap(etl::bitset_ext<Active_Bits, TElement>& other) ETL_NOEXCEPT
    {
      implementation::swap(pbuffer, other.pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 span_type span() ETL_NOEXCEPT
    {
      return span_type(pbuffer, Number_Of_Elements);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 const_span_type span() const ETL_NOEXCEPT
    {
      return const_span_type(pbuffer, Number_Of_Elements);
    }
 
  private:
 
    // The implementation of the bitset functionality.
    typedef etl::bitset_impl<element_type, (Number_Of_Elements == 1U) ? etl::bitset_storage_model::Single : etl::bitset_storage_model::Multi>
      implementation;
 
    // Pointer to the storage for the bitset.
    element_type* pbuffer;
  };
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bool operator!=(const etl::bitset_ext<Active_Bits, TElement>& lhs, const etl::bitset_ext<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    return !(lhs == rhs);
  }
 
  //*************************************************************************
  //*************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 void swap(etl::bitset_ext<Active_Bits, TElement>& lhs, etl::bitset_ext<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    lhs.swap(rhs);
  }
 
  namespace private_bitset
  {
    //*************************************************************************
    //*************************************************************************
    template <typename TLhsSpan, typename TRhsSpan>
    bool compare_bitset_spans(const TLhsSpan& lhs_span, const TRhsSpan& rhs_span)
    {
      typedef typename TLhsSpan::value_type lhs_element_t;
      typedef typename TRhsSpan::value_type rhs_element_t;
 
      const int steps = static_cast<int>(sizeof(lhs_element_t) / sizeof(rhs_element_t));
 
      typename TLhsSpan::iterator lhs_itr = lhs_span.begin();
      typename TRhsSpan::iterator rhs_itr = rhs_span.begin();
 
      while (lhs_itr != lhs_span.end())
      {
        const lhs_element_t& lhs_value = *lhs_itr;
 
        // Build the rhs element in terms of the lhs element type.
        lhs_element_t rhs_value = 0;
 
        const int shift_step = etl::integral_limits<rhs_element_t>::bits;
        int       shift      = 0;
 
        for (int i = 0; i < steps; ++i)
        {
          rhs_value |= (static_cast<lhs_element_t>(*rhs_itr) << shift);
          ++rhs_itr;
          shift += shift_step;
        }
 
        if (lhs_value != rhs_value)
        {
          return false;
        }
 
        ++lhs_itr;
      }
 
      return true;
    }
  } // namespace private_bitset
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TLhsElement, typename TRhsElement>
  ETL_CONSTEXPR14 typename etl::enable_if<!etl::is_same<TLhsElement, TRhsElement>::value, bool>::type
    operator==(const etl::bitset<Active_Bits, TLhsElement>& lhs, const etl::bitset<Active_Bits, TRhsElement>& rhs) ETL_NOEXCEPT
  {
    // Get a span of each type.
    typename etl::bitset<Active_Bits, TLhsElement>::const_span_type lhs_span = lhs.span();
    typename etl::bitset<Active_Bits, TRhsElement>::const_span_type rhs_span = rhs.span();
 
    // Put the bitset with the largest element type as the first argument.
    if ETL_IF_CONSTEXPR (sizeof(TLhsElement) > sizeof(TRhsElement))
    {
      return etl::private_bitset::compare_bitset_spans(lhs_span, rhs_span);
    }
    else
    {
      return etl::private_bitset::compare_bitset_spans(rhs_span, lhs_span);
    }
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TLhsElement, typename TRhsElement>
  ETL_CONSTEXPR14 typename etl::enable_if<!etl::is_same<TLhsElement, TRhsElement>::value, bool>::type
    operator!=(const etl::bitset<Active_Bits, TLhsElement>& lhs, const etl::bitset<Active_Bits, TRhsElement>& rhs) ETL_NOEXCEPT
  {
    return !(lhs == rhs);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TLhsElement, typename TRhsElement>
  ETL_CONSTEXPR14 typename etl::enable_if<!etl::is_same<TLhsElement, TRhsElement>::value, bool>::type
    operator==(const etl::bitset_ext<Active_Bits, TLhsElement>& lhs, const etl::bitset_ext<Active_Bits, TRhsElement>& rhs) ETL_NOEXCEPT
  {
    // Get a span of each type.
    typename etl::bitset_ext<Active_Bits, TLhsElement>::const_span_type lhs_span = lhs.span();
    typename etl::bitset_ext<Active_Bits, TRhsElement>::const_span_type rhs_span = rhs.span();
 
    // Put the bitset with the largest element type as the first argument.
    if ETL_IF_CONSTEXPR (sizeof(TLhsElement) > sizeof(TRhsElement))
    {
      return etl::private_bitset::compare_bitset_spans(lhs_span, rhs_span);
    }
    else
    {
      return etl::private_bitset::compare_bitset_spans(rhs_span, lhs_span);
    }
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TLhsElement, typename TRhsElement>
  ETL_CONSTEXPR14 typename etl::enable_if<!etl::is_same<TLhsElement, TRhsElement>::value, bool>::type
    operator!=(const etl::bitset_ext<Active_Bits, TLhsElement>& lhs, const etl::bitset_ext<Active_Bits, TRhsElement>& rhs) ETL_NOEXCEPT
  {
    return !(lhs == rhs);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bool operator==(const etl::bitset<Active_Bits, TElement>& lhs, const etl::bitset_ext<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    const char   Storage_Model      = etl::bitset<Active_Bits, TElement>::Storage_Model;
    const size_t Number_Of_Elements = etl::bitset<Active_Bits, TElement>::Number_Of_Elements;
 
    typename etl::bitset<Active_Bits, TElement>::const_span_type     lhs_span = lhs.span();
    typename etl::bitset_ext<Active_Bits, TElement>::const_span_type rhs_span = rhs.span();
 
    typedef etl::bitset_impl<TElement, Storage_Model> implementation;
 
    return implementation::operator_equality(lhs_span.begin(), rhs_span.begin(), Number_Of_Elements);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bool operator!=(const etl::bitset<Active_Bits, TElement>& lhs, const etl::bitset_ext<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    return !(lhs == rhs);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bool operator==(const etl::bitset_ext<Active_Bits, TElement>& lhs, const etl::bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    const char   Storage_Model      = etl::bitset<Active_Bits, TElement>::Storage_Model;
    const size_t Number_Of_Elements = etl::bitset<Active_Bits, TElement>::Number_Of_Elements;
 
    typename etl::bitset_ext<Active_Bits, TElement>::const_span_type lhs_span = lhs.span();
    typename etl::bitset<Active_Bits, TElement>::const_span_type     rhs_span = rhs.span();
 
    typedef etl::bitset_impl<TElement, Storage_Model> implementation;
 
    return implementation::operator_equality(lhs_span.begin(), rhs_span.begin(), Number_Of_Elements);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TElement>
  ETL_CONSTEXPR14 bool operator!=(const etl::bitset_ext<Active_Bits, TElement>& lhs, const etl::bitset<Active_Bits, TElement>& rhs) ETL_NOEXCEPT
  {
    return !(lhs == rhs);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TLhsElement, typename TRhsElement>
  ETL_CONSTEXPR14 typename etl::enable_if<!etl::is_same<TLhsElement, TRhsElement>::value, bool>::type
    operator==(const etl::bitset<Active_Bits, TLhsElement>& lhs, const etl::bitset_ext<Active_Bits, TRhsElement>& rhs) ETL_NOEXCEPT
  {
    // Get a span of each type.
    typename etl::bitset<Active_Bits, TLhsElement>::const_span_type     lhs_span = lhs.span();
    typename etl::bitset_ext<Active_Bits, TRhsElement>::const_span_type rhs_span = rhs.span();
 
    // Put the bitset with the largest element type as the first argument.
    if ETL_IF_CONSTEXPR (sizeof(TLhsElement) > sizeof(TRhsElement))
    {
      return etl::private_bitset::compare_bitset_spans(lhs_span, rhs_span);
    }
    else
    {
      return etl::private_bitset::compare_bitset_spans(rhs_span, lhs_span);
    }
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TLhsElement, typename TRhsElement>
  ETL_CONSTEXPR14 typename etl::enable_if<!etl::is_same<TLhsElement, TRhsElement>::value, bool>::type
    operator!=(const etl::bitset<Active_Bits, TLhsElement>& lhs, const etl::bitset_ext<Active_Bits, TRhsElement>& rhs) ETL_NOEXCEPT
  {
    return !(lhs == rhs);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TLhsElement, typename TRhsElement>
  ETL_CONSTEXPR14 typename etl::enable_if<!etl::is_same<TLhsElement, TRhsElement>::value, bool>::type
    operator==(const etl::bitset_ext<Active_Bits, TLhsElement>& lhs, const etl::bitset<Active_Bits, TRhsElement>& rhs) ETL_NOEXCEPT
  {
    // Get a span of each type.
    typename etl::bitset_ext<Active_Bits, TLhsElement>::const_span_type lhs_span = lhs.span();
    typename etl::bitset<Active_Bits, TRhsElement>::const_span_type     rhs_span = rhs.span();
 
    // Put the bitset with the largest element type as the first argument.
    if ETL_IF_CONSTEXPR (sizeof(TLhsElement) > sizeof(TRhsElement))
    {
      return etl::private_bitset::compare_bitset_spans(lhs_span, rhs_span);
    }
    else
    {
      return etl::private_bitset::compare_bitset_spans(rhs_span, lhs_span);
    }
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Active_Bits, typename TLhsElement, typename TRhsElement>
  ETL_CONSTEXPR14 typename etl::enable_if<!etl::is_same<TLhsElement, TRhsElement>::value, bool>::type
    operator!=(const etl::bitset_ext<Active_Bits, TLhsElement>& lhs, const etl::bitset<Active_Bits, TRhsElement>& rhs) ETL_NOEXCEPT
  {
    return !(lhs == rhs);
  }
 
} // namespace etl
 
#include "minmax_pop.h"
 
#endif