itkSize.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 itkSize_h
#define itkSize_h
 
#include "itkIntTypes.h"
#include "itkMacro.h"
#include "itkMakeFilled.h"
#include <algorithm>   // For copy_n.
#include <cstddef>     // For ptrdiff_t.
#include <type_traits> // For is_integral.
#include <memory>
 
namespace itk
{
 
template <unsigned int VDimension = 2>
struct ITK_TEMPLATE_EXPORT Size final
{
public:
  // Using the `rule of zero` to this aggregate type
  // C++20 changes the definition of aggregate such that classes with any user-declared ctors are no longer aggregates.
 
  using Self = Size;
 
  using SizeType = Size<VDimension>;
  using SizeValueType = itk::SizeValueType;
 
  static constexpr unsigned int Dimension = VDimension;
 
  static constexpr unsigned int
  GetSizeDimension()
  {
    return VDimension;
  }
 
  const Self
  operator+(const Self & vec) const
  {
    Self result;
 
    for (unsigned int i = 0; i < VDimension; ++i)
    {
      result[i] = m_InternalArray[i] + vec.m_InternalArray[i];
    }
    return result;
  }
 
  const Self &
  operator+=(const Self & vec)
  {
    for (unsigned int i = 0; i < VDimension; ++i)
    {
      m_InternalArray[i] += vec.m_InternalArray[i];
    }
    return *this;
  }
  const Self
  operator-(const Self & vec) const
  {
    Self result;
 
    for (unsigned int i = 0; i < VDimension; ++i)
    {
      result[i] = m_InternalArray[i] - vec.m_InternalArray[i];
    }
    return result;
  }
 
  const Self &
  operator-=(const Self & vec)
  {
    for (unsigned int i = 0; i < VDimension; ++i)
    {
      m_InternalArray[i] -= vec.m_InternalArray[i];
    }
    return *this;
  }
  const Self operator*(const Self & vec) const
  {
    Self result;
 
    for (unsigned int i = 0; i < VDimension; ++i)
    {
      result[i] = m_InternalArray[i] * vec.m_InternalArray[i];
    }
    return result;
  }
 
  const Self &
  operator*=(const Self & vec)
  {
    for (unsigned int i = 0; i < VDimension; ++i)
    {
      m_InternalArray[i] *= vec.m_InternalArray[i];
    }
    return *this;
  }
  const SizeValueType *
  GetSize() const
  {
    return m_InternalArray;
  }
 
  void
  SetSize(const SizeValueType val[VDimension])
  {
    std::copy_n(val, VDimension, m_InternalArray);
  }
 
  void
  SetElement(unsigned long element, SizeValueType val)
  {
    m_InternalArray[element] = val;
  }
 
  SizeValueType
  GetElement(unsigned long element) const
  {
    return m_InternalArray[element];
  }
 
  void
  Fill(SizeValueType value)
  {
    std::fill_n(begin(), size(), value);
  } // MATCH std::array assign, ITK Fill
 
  [[nodiscard]] constexpr SizeValueType
  CalculateProductOfElements() const
  {
    SizeValueType product{ 1 };
 
    for (const SizeValueType value : m_InternalArray)
    {
      product *= value;
    }
    return product;
  }
 
  /*
   *  Ask the compiler to align a type to the maximum useful alignment for the target
   *  machine you are compiling for. Whenever you leave out the alignment factor in an
   *  aligned attribute specification, the compiler automatically sets the alignment
   *  for the type to the largest alignment that is ever used for any data type on
   *  the target machine you are compiling for. Doing this can often make copy
   *  operations more efficient, because the compiler can use whatever instructions
   *  copy the biggest chunks of memory when performing copies to or from the variables
   *  that have types that you have aligned this way.
   */
  static_assert(VDimension > 0, "Error: Only positive value sized VDimension allowed");
  alignas(SizeValueType) SizeValueType m_InternalArray[VDimension];
  // ======================= Mirror the access pattern behavior of the std::array class
  using value_type = itk::SizeValueType;
  using reference = value_type &;
  using const_reference = const value_type &;
  using iterator = value_type *;
  using const_iterator = const value_type *;
  using size_type = unsigned int;
  using difference_type = ptrdiff_t;
  using reverse_iterator = std::reverse_iterator<iterator>;
  using const_reverse_iterator = std::reverse_iterator<const_iterator>;
 
  void
  assign(const value_type & newValue)
  {
    std::fill_n(begin(), size(), newValue);
  }
 
  void
  swap(Size & other)
  {
    std::swap(m_InternalArray, other.m_InternalArray);
  }
 
  constexpr const_iterator
  cbegin() const
  {
    return &m_InternalArray[0];
  }
 
  constexpr iterator
  begin()
  {
    return &m_InternalArray[0];
  }
 
  constexpr const_iterator
  begin() const
  {
    return &m_InternalArray[0];
  }
 
  constexpr const_iterator
  cend() const
  {
    return &m_InternalArray[VDimension];
  }
 
  constexpr iterator
  end()
  {
    return &m_InternalArray[VDimension];
  }
 
  constexpr const_iterator
  end() const
  {
    return &m_InternalArray[VDimension];
  }
 
  reverse_iterator
  rbegin()
  {
    return reverse_iterator(end());
  }
 
  const_reverse_iterator
  rbegin() const
  {
    return const_reverse_iterator(end());
  }
 
  reverse_iterator
  rend()
  {
    return reverse_iterator(begin());
  }
 
  const_reverse_iterator
  rend() const
  {
    return const_reverse_iterator(begin());
  }
 
  constexpr size_type
  size() const
  {
    return VDimension;
  }
 
  constexpr size_type
  max_size() const
  {
    return VDimension;
  }
 
  constexpr bool
  empty() const
  {
    return false;
  }
 
  constexpr reference operator[](size_type pos) { return m_InternalArray[pos]; }
 
  constexpr const_reference operator[](size_type pos) const { return m_InternalArray[pos]; }
 
  reference
  at(size_type pos)
  {
    ExceptionThrowingBoundsCheck(pos);
    return m_InternalArray[pos];
  }
 
  const_reference
  at(size_type pos) const
  {
    ExceptionThrowingBoundsCheck(pos);
    return m_InternalArray[pos];
  }
 
  constexpr reference
  front()
  {
    return *begin();
  }
 
  constexpr const_reference
  front() const
  {
    return *begin();
  }
 
  constexpr reference
  back()
  {
    return VDimension ? *(end() - 1) : *end();
  }
 
  constexpr const_reference
  back() const
  {
    return VDimension ? *(end() - 1) : *end();
  }
 
  SizeValueType *
  data()
  {
    return &m_InternalArray[0];
  }
 
  const SizeValueType *
  data() const
  {
    return &m_InternalArray[0];
  }
 
private:
  void
  ExceptionThrowingBoundsCheck(size_type pos) const
  {
    if (pos >= VDimension)
    {
      throw std::out_of_range("array::ExceptionThrowingBoundsCheck");
    }
  }
 
public:
  static constexpr Self
  Filled(const SizeValueType value)
  {
    return MakeFilled<Self>(value);
  }
 
}; //------------ End struct Size
 
 
template <unsigned int VDimension>
std::ostream &
operator<<(std::ostream & os, const Size<VDimension> & obj)
{
  os << '[';
  for (unsigned int i = 0; i + 1 < VDimension; ++i)
  {
    os << obj[i] << ", ";
  }
  if constexpr (VDimension >= 1)
  {
    os << obj[VDimension - 1];
  }
  os << ']';
  return os;
}
 
// ======================= Mirror the access pattern behavior of the std::array class
// Array comparisons.
template <unsigned int VDimension>
inline bool
operator==(const Size<VDimension> & one, const Size<VDimension> & two)
{
  return std::equal(one.begin(), one.end(), two.begin());
}
 
template <unsigned int VDimension>
inline bool
operator!=(const Size<VDimension> & one, const Size<VDimension> & two)
{
  return !(one == two);
}
 
template <unsigned int VDimension>
inline bool
operator<(const Size<VDimension> & one, const Size<VDimension> & two)
{
  return std::lexicographical_compare(one.begin(), one.end(), two.begin(), two.end());
}
 
template <unsigned int VDimension>
inline bool
operator>(const Size<VDimension> & one, const Size<VDimension> & two)
{
  return two < one;
}
 
template <unsigned int VDimension>
inline bool
operator<=(const Size<VDimension> & one, const Size<VDimension> & two)
{
  return !(one > two);
}
 
template <unsigned int VDimension>
inline bool
operator>=(const Size<VDimension> & one, const Size<VDimension> & two)
{
  return !(one < two);
}
 
// Specialized algorithms [6.2.2.2].
template <unsigned int VDimension>
inline void
swap(Size<VDimension> & one, Size<VDimension> & two)
{
  std::swap(one.m_InternalArray, two.m_InternalArray);
}
 
 
template <typename... T>
auto
MakeSize(const T... values)
{
  const auto toValueType = [](const auto value) {
    static_assert(std::is_integral_v<decltype(value)>, "Each value must have an integral type!");
    return static_cast<SizeValueType>(value);
  };
  return Size<sizeof...(T)>{ { toValueType(values)... } };
}
} // end namespace itk
 
#endif