STYLE: Clean-up ByteSwapper, using SwapWriteRange helper function

Aims to reduce code duplication.

- Follow-up to pull request InsightSoftwareConsortium#4855
commit 3b04ad1
"STYLE: Clean-up ByteSwapper, using private `SwapBytes` helper function"

Modules/Core/Common/include/itkByteSwapper.h

@@ -201,6 +201,10 @@ class ITK_TEMPLATE_EXPORT ByteSwapper : public Object
  static void
  SwapBytes(T &);
 
+ /** Swaps and writes the specified elements to the specified output stream. */
+ static void
+ SwapWriteRange(const T * ptr, SizeValueType numberOfElements, std::ostream & outputStream);
+
  static constexpr bool m_SystemIsBigEndian{
 #ifdef CMAKE_WORDS_BIGENDIAN
  true

Modules/Core/Common/include/itkByteSwapper.hxx

@@ -72,20 +72,7 @@ ByteSwapper<T>::SwapWriteRangeFromSystemToBigEndian(const T * p, int num, std::o
  }
  else
  {
- switch (sizeof(T))
- {
- case 2:
- Self::SwapWrite2Range(p, num, fp);
- return;
- case 4:
- Self::SwapWrite4Range(p, num, fp);
- return;
- case 8:
- Self::SwapWrite8Range(p, num, fp);
- return;
- default:
- itkGenericExceptionMacro("Cannot swap number of bytes requested");
- }
+ SwapWriteRange(p, num, *fp);
  }
 }
 
@@ -118,20 +105,7 @@ ByteSwapper<T>::SwapWriteRangeFromSystemToLittleEndian(const T * p, int num, std
 {
  if constexpr (m_SystemIsBigEndian && sizeof(T) > 1)
  {
- switch (sizeof(T))
- {
- case 2:
- Self::SwapWrite2Range(p, num, fp);
- return;
- case 4:
- Self::SwapWrite4Range(p, num, fp);
- return;
- case 8:
- Self::SwapWrite8Range(p, num, fp);
- return;
- default:
- itkGenericExceptionMacro("Cannot swap number of bytes requested");
- }
+ SwapWriteRange(p, num, *fp);
  }
  else
  {
@@ -308,7 +282,7 @@ ByteSwapper<T>::SwapWrite8Range(const void * ptr, BufferSizeType num, std::ostre
 }
 
 
-// The following member function is private:
+// The following member functions are private:
 
 template <typename T>
 void
@@ -333,6 +307,27 @@ ByteSwapper<T>::SwapBytes(T & value)
  }
 }
 
+template <typename T>
+void
+ByteSwapper<T>::SwapWriteRange(const T * buffer, SizeValueType numberOfElements, std::ostream & outputStream)
+{
+ auto chunkSize = std::min(numberOfElements, SizeValueType{ 1000000 });
+
+ const auto chunk = make_unique_for_overwrite<T[]>(chunkSize);
+
+ while (numberOfElements > 0)
+ {
+ std::copy_n(buffer, chunkSize, chunk.get());
+ std::for_each_n(chunk.get(), chunkSize, [](T & element) { SwapBytes(element); });
+
+ outputStream.write(reinterpret_cast<const char *>(chunk.get()),
+ static_cast<std::streamsize>(chunkSize * sizeof(T)));
+ buffer += chunkSize;
+ numberOfElements -= chunkSize;
+ chunkSize = std::min(numberOfElements, chunkSize);
+ }
+}
+
 } // end namespace itk
 
 #endif