itkByteSwapper.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.
 *
 *=========================================================================*/
/*=========================================================================
 *
 *  Portions of this file are subject to the VTK Toolkit Version 3 copyright.
 *
 *  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
 *
 *  For complete copyright, license and disclaimer of warranty information
 *  please refer to the NOTICE file at the top of the ITK source tree.
 *
 *=========================================================================*/
#ifndef itkByteSwapper_h
#define itkByteSwapper_h
 
#include "itkObject.h"
#include "itkObjectFactory.h"
#include "itkIntTypes.h"
 
#if __has_include(<version>)
#  include <version>
#endif
#if defined(__cpp_lib_endian) // ABI-neutral
#  include <bit>
#endif
 
namespace itk
{
 
template <typename T>
class ITK_TEMPLATE_EXPORT ByteSwapper : public Object
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(ByteSwapper);

  using Self = ByteSwapper;
  using Superclass = Object;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;
 
#ifndef ITK_FUTURE_LEGACY_REMOVE
  using OStreamType
    [[deprecated("ByteSwapper::OStreamType is deprecated from ITK 6. Just use `std::ostream` instead!")]] =
      std::ostream;
#endif

  itkOverrideGetNameOfClassMacro(ByteSwapper);

  static constexpr bool
  SystemIsBigEndian()
  {
    return m_SystemIsBigEndian;
  }
 
  static constexpr bool
  SystemIsBE()
  {
    return SystemIsBigEndian();
  }
  static constexpr bool
  SystemIsLittleEndian()
  {
    return !m_SystemIsBigEndian;
  }
 
  static constexpr bool
  SystemIsLE()
  {
    return SystemIsLittleEndian();
  }

  static void
  SwapFromSystemToBigEndian(T * p);

  using BufferSizeType = SizeValueType;

  static void
  SwapRangeFromSystemToBigEndian(T * p, BufferSizeType num);

  static void
  SwapWriteRangeFromSystemToBigEndian(const T * p, int num, std::ostream * fp);

  static void
  SwapFromSystemToLittleEndian(T * p);

  static void
  SwapRangeFromSystemToLittleEndian(T * p, BufferSizeType num);

  static void
  SwapWriteRangeFromSystemToLittleEndian(const T * p, int num, std::ostream * fp);
 
protected:
  ByteSwapper() = default;
  ~ByteSwapper() override = default;
 
private:
  static void
  SwapBytes(T &);

  static void
  SwapWriteRange(const T * buffer, SizeValueType numberOfElements, std::ostream & outputStream);
 
  static constexpr bool m_SystemIsBigEndian{
#if defined(__cpp_lib_endian) // ABI-neutral
    std::endian::native == std::endian::big
#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__)
    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#elif defined(__BIG_ENDIAN__)
    true
#elif defined(__LITTLE_ENDIAN__) || defined(_WIN32)
    false
#else
#  error "The byte order of the target architecture is unknown to this compiler."
#endif
  };
};
} // end namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkByteSwapper.hxx"
#endif
 
#endif