ENH: Replace OBJMeshIO::OpenFile() with MeshIOBase::OpenInputFile()

`MeshIOBase::OpenInputFile()` is intended to be used by other `MeshIO`
classes as well.

Author: N-Dekker

Modules/IO/MeshBase/include/itkMeshIOBase.h

@@ -640,6 +640,10 @@ class ITKIOMeshBase_EXPORT MeshIOBase : public LightProcessObject
   void
   AddSupportedWriteExtension(const char * extension);
 
+  /** Opens the input file specified by the current FileName */
+  [[nodiscard]] std::ifstream
+  OpenInputFile() const;
+
   /** Read data from input file stream to buffer with ascii style */
   template <typename T>
   void

Modules/IO/MeshBase/src/itkMeshIOBase.cxx

@@ -17,6 +17,7 @@
  *=========================================================================*/
 
 #include "itkMeshIOBase.h"
+#include "itksys/SystemTools.hxx"
 
 namespace itk
 {
@@ -227,4 +228,30 @@ MeshIOBase::PrintSelf(std::ostream & os, Indent indent) const
   os << indent << "Point pixel component type: " << GetComponentTypeAsString(m_PointPixelComponentType) << std::endl;
   os << indent << "Cell  pixel component type: " << GetComponentTypeAsString(m_CellPixelComponentType) << std::endl;
 }
+
+
+std::ifstream
+MeshIOBase::OpenInputFile() const
+{
+  if (m_FileName.empty())
+  {
+    itkExceptionStringMacro("No input FileName");
+  }
+
+  if (!itksys::SystemTools::FileExists(m_FileName.c_str()))
+  {
+    itkExceptionMacro("File " << m_FileName << " does not exist");
+  }
+
+  // Open the input file in binary mode. (Text mode does not work well on Windows, when using tellg() and seekg().)
+  std::ifstream inputFile(m_FileName, std::ios::binary);
+
+  // Test whether the file was opened
+  if (!inputFile.is_open())
+  {
+    itkExceptionMacro("Unable to open file " << m_FileName);
+  }
+
+  return inputFile;
+}
 } // namespace itk

Modules/IO/MeshOBJ/include/itkOBJMeshIO.h

@@ -177,10 +177,6 @@ class ITKIOMeshOBJ_EXPORT OBJMeshIO : public MeshIOBase
 
   void
   PrintSelf(std::ostream & os, Indent indent) const override;
-
-private:
-  [[nodiscard]] std::ifstream
-  OpenFile() const;
 };
 } // end namespace itk
 

Modules/IO/MeshOBJ/src/itkOBJMeshIO.cxx

@@ -57,34 +57,6 @@ OBJMeshIO::CanWriteFile(const char * fileName)
   return true;
 }
 
-std::ifstream
-OBJMeshIO::OpenFile() const
-{
-  if (this->m_FileName.empty())
-  {
-    itkExceptionStringMacro("No input FileName");
-  }
-
-  if (!itksys::SystemTools::FileExists(m_FileName.c_str()))
-  {
-    itkExceptionMacro("File " << this->m_FileName << " does not exist");
-  }
-
-  // Read file as ascii
-  // Due to the windows couldn't work well for tellg() and seekg() for ASCII
-  // mode, hence we
-  // open the file with std::ios::binary
-  std::ifstream inputFile(m_FileName, std::ios::binary);
-
-  // Test whether the file was opened
-  if (!inputFile.is_open())
-  {
-    itkExceptionMacro("Unable to open file " << this->m_FileName);
-  }
-
-  return inputFile;
-}
-
 
 bool
 OBJMeshIO::SplitLine(const std::string & line, std::string & type, std::string & content)
@@ -118,7 +90,7 @@ void
 OBJMeshIO::ReadMeshInformation()
 {
   // Define input file stream and attach it to input file
-  std::ifstream inputFile = OpenFile();
+  std::ifstream inputFile = MeshIOBase::OpenInputFile();
 
   // Read and analyze the first line in the file
   SizeValueType numberOfCellPoints = 0;
@@ -188,7 +160,7 @@ void
 OBJMeshIO::ReadPoints(void * buffer)
 {
   // Define input file stream and attach it to input file
-  std::ifstream inputFile = OpenFile();
+  std::ifstream inputFile = MeshIOBase::OpenInputFile();
 
   // Number of data array
   auto *        data = static_cast<float *>(buffer);
@@ -219,7 +191,7 @@ void
 OBJMeshIO::ReadCells(void * buffer)
 {
   // Define input file stream and attach it to input file
-  std::ifstream inputFile = OpenFile();
+  std::ifstream inputFile = MeshIOBase::OpenInputFile();
 
   // Read and analyze the first line in the file
   const auto    data = make_unique_for_overwrite<long[]>(this->m_CellBufferSize - this->m_NumberOfCells);
@@ -273,7 +245,7 @@ void
 OBJMeshIO::ReadPointData(void * buffer)
 {
   // Define input file stream and attach it to input file
-  std::ifstream inputFile = OpenFile();
+  std::ifstream inputFile = MeshIOBase::OpenInputFile();
 
   // Number of data array
   auto *        data = static_cast<float *>(buffer);