itkFixedArray.h

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/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef itkFixedArray_h
#define itkFixedArray_h
 
#include "itkMacro.h"
#include "itkMakeFilled.h"
#include <algorithm>
#include <array>
 
namespace itk
{

template <typename TValue, unsigned int VLength = 3>
class ITK_TEMPLATE_EXPORT FixedArray
{
  static_assert(VLength > 0);
 
public:
  static constexpr unsigned int Length = VLength;

  static constexpr unsigned int Dimension = VLength;

  using ValueType = TValue;

  using CArray = ValueType[VLength];

  using Iterator = ValueType *;

  using ConstIterator = const ValueType *;
 
  class ConstReverseIterator;

  class ReverseIterator
  {
  public:
    explicit ReverseIterator(Iterator i)
      : m_Iterator(i)
    {}
    ReverseIterator
    operator++()
    {
      return ReverseIterator(--m_Iterator);
    }
    ReverseIterator
    operator++(int)
    {
      return ReverseIterator(m_Iterator--);
    }
    ReverseIterator
    operator--()
    {
      return ReverseIterator(++m_Iterator);
    }
    ReverseIterator
    operator--(int)
    {
      return ReverseIterator(m_Iterator++);
    }
    Iterator
    operator->() const
    {
      return m_Iterator - 1;
    }
    ValueType &
    operator*() const
    {
      return *(m_Iterator - 1);
    }
 
    bool
    operator==(const ReverseIterator & rit) const
    {
      return m_Iterator == rit.m_Iterator;
    }
 
    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(ReverseIterator);
 
  private:
    Iterator m_Iterator;
    friend class ConstReverseIterator;
  };

  class ConstReverseIterator
  {
  public:
    explicit ConstReverseIterator(ConstIterator i)
      : m_Iterator(i)
    {}
    ConstReverseIterator(const ReverseIterator & rit)
      : m_Iterator(rit.m_Iterator)
    {}
    ConstReverseIterator
    operator++()
    {
      return ConstReverseIterator(--m_Iterator);
    }
    ConstReverseIterator
    operator++(int)
    {
      return ConstReverseIterator(m_Iterator--);
    }
    ConstReverseIterator
    operator--()
    {
      return ConstReverseIterator(++m_Iterator);
    }
    ConstReverseIterator
    operator--(int)
    {
      return ConstReverseIterator(m_Iterator++);
    }
    ConstIterator
    operator->() const
    {
      return m_Iterator - 1;
    }
    const ValueType &
    operator*() const
    {
      return *(m_Iterator - 1);
    }
 
    bool
    operator==(const ConstReverseIterator & rit) const
    {
      return m_Iterator == rit.m_Iterator;
    }
 
    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(ConstReverseIterator);
 
  private:
    ConstIterator m_Iterator;
  };

  using value_type = TValue;

  using pointer = ValueType *;

  using const_pointer = const ValueType *;

  using reference = ValueType &;

  using const_reference = const ValueType &;

  using iterator = ValueType *;

  using const_iterator = const ValueType *;
 
  using reverse_iterator = std::reverse_iterator<iterator>;
 
  using const_reverse_iterator = std::reverse_iterator<const_iterator>;
 
  using SizeType = unsigned int;
 
public:
  FixedArray() = default;

  FixedArray(const ValueType r[VLength]);
  FixedArray(const ValueType &);
  explicit FixedArray(const std::array<ValueType, VLength> & stdArray)
  {
    std::copy_n(stdArray.cbegin(), VLength, m_InternalArray);
  }

  template <typename TFixedArrayValueType>
  FixedArray(const FixedArray<TFixedArrayValueType, VLength> & r)
  {
    auto input = r.cbegin();
 
    for (auto & element : m_InternalArray)
    {
      element = static_cast<TValue>(*input++);
    }
  }
 
  template <typename TScalarValue>
  FixedArray(const TScalarValue * r)
  {
    std::copy_n(r, VLength, m_InternalArray);
  }

  template <typename TFixedArrayValueType>
  FixedArray &
  operator=(const FixedArray<TFixedArrayValueType, VLength> & r)
  {
    auto input = r.cbegin();
 
    for (auto & element : m_InternalArray)
    {
      element = static_cast<TValue>(*input++);
    }
    return *this;
  }
 
  FixedArray &
  operator=(const ValueType r[VLength]);

  bool
  operator==(const FixedArray & r) const;
 
  ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(FixedArray);
 

  // false positive warnings with GCC
  ITK_GCC_PRAGMA_PUSH
  ITK_GCC_SUPPRESS_Warray_bounds
  constexpr reference
  operator[](unsigned int index)
  {
    return m_InternalArray[index];
  }
  constexpr const_reference
  operator[](unsigned int index) const
  {
    return m_InternalArray[index];
  }
  ITK_GCC_PRAGMA_POP
  void
  SetElement(unsigned int index, const_reference value)
  {
    m_InternalArray[index] = value;
  }
  [[nodiscard]] const_reference
  GetElement(unsigned int index) const
  {
    return m_InternalArray[index];
  }

 
  [[nodiscard]] constexpr reference
  front()
  {
    return m_InternalArray[0];
  }
 
  [[nodiscard]] constexpr const_reference
  front() const
  {
    return m_InternalArray[0];
  }
 
  [[nodiscard]] constexpr reference
  back()
  {
    return m_InternalArray[VLength - 1];
  }
 
  [[nodiscard]] constexpr const_reference
  back() const
  {
    return m_InternalArray[VLength - 1];
  }

  ValueType *
  GetDataPointer()
  {
    return m_InternalArray;
  }
 
  [[nodiscard]] const ValueType *
  GetDataPointer() const
  {
    return m_InternalArray;
  }
 
  [[nodiscard]] ValueType *
  data()
  {
    return m_InternalArray;
  }
 
  [[nodiscard]] const ValueType *
  data() const
  {
    return m_InternalArray;
  }

  Iterator
  Begin();

  [[nodiscard]] ConstIterator
  Begin() const;

  Iterator
  End();

  [[nodiscard]] ConstIterator
  End() const;

  itkLegacyMacro(ReverseIterator rBegin();)

  itkLegacyMacro(ConstReverseIterator rBegin() const;)

  itkLegacyMacro(ReverseIterator rEnd();)

  itkLegacyMacro(ConstReverseIterator rEnd() const;)
 
  [[nodiscard]] constexpr const_iterator
  cbegin() const noexcept
  {
    return m_InternalArray;
  }
 
  [[nodiscard]] constexpr iterator
  begin() noexcept
  {
    return m_InternalArray;
  }
 
  [[nodiscard]] constexpr const_iterator
  begin() const noexcept
  {
    return this->cbegin();
  }
 
  [[nodiscard]] constexpr const_iterator
  cend() const noexcept
  {
    return m_InternalArray + VLength;
  }
 
  [[nodiscard]] constexpr iterator
  end() noexcept
  {
    return m_InternalArray + VLength;
  }
 
  [[nodiscard]] constexpr const_iterator
  end() const noexcept
  {
    return this->cend();
  }
 
  [[nodiscard]] reverse_iterator
  rbegin()
  {
    return reverse_iterator{ this->end() };
  }
 
  [[nodiscard]] const_reverse_iterator
  crbegin() const
  {
    return const_reverse_iterator{ this->cend() };
  }
 
  [[nodiscard]] const_reverse_iterator
  rbegin() const
  {
    return this->crbegin();
  }
 
  [[nodiscard]] reverse_iterator
  rend()
  {
    return reverse_iterator{ this->begin() };
  }
 
  [[nodiscard]] const_reverse_iterator
  crend() const
  {
    return const_reverse_iterator{ this->cbegin() };
  }
 
  [[nodiscard]] const_reverse_iterator
  rend() const
  {
    return this->crend();
  }

  [[nodiscard]] SizeType
  Size() const;
 
  [[nodiscard]] constexpr SizeType
  size() const
  {
    return VLength;
  }
 
  [[nodiscard]] constexpr bool
  empty() const noexcept
  {
    return false;
  }

  void
  Fill(const ValueType &);
 
  void
  swap(FixedArray & other) noexcept
  {
    std::swap(m_InternalArray, other.m_InternalArray);
  }
 
private:
  CArray m_InternalArray;
 
public:
  static constexpr FixedArray
  Filled(const ValueType & value)
  {
    return MakeFilled<FixedArray>(value);
  }
};
 
template <typename TValue, unsigned int VLength>
std::ostream &
operator<<(std::ostream & os, const FixedArray<TValue, VLength> & arr);
 
 
template <typename TValue, unsigned int VLength>
inline void
swap(FixedArray<TValue, VLength> & a, FixedArray<TValue, VLength> & b) noexcept
{
  a.swap(b);
}
 
} // namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkFixedArray.hxx"
#endif
 
#include "itkNumericTraitsFixedArrayPixel.h"
 
#endif