Index: CMakeLists.txt
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/CMakeLists.txt,v
retrieving revision 1.157
diff -u -r1.157 CMakeLists.txt
--- CMakeLists.txt	10 May 2007 17:14:11 -0000	1.157
+++ CMakeLists.txt	1 Jul 2007 22:06:12 -0000
@@ -93,6 +93,7 @@
 vtkSLCReader.cxx
 vtkSTLReader.cxx
 vtkSTLWriter.cxx
+vtkStringStream.cxx
 vtkSimplePointsReader.cxx
 vtkSortFileNames.cxx
 vtkStructuredGridReader.cxx
Index: vtkXMLReader.cxx
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/vtkXMLReader.cxx,v
retrieving revision 1.45
diff -u -r1.45 vtkXMLReader.cxx
--- vtkXMLReader.cxx	15 Feb 2007 21:04:23 -0000	1.45
+++ vtkXMLReader.cxx	1 Jul 2007 22:08:22 -0000
@@ -28,6 +28,7 @@
 #include "vtkInformation.h"
 #include "vtkInformationVector.h"
 #include "vtkStreamingDemandDrivenPipeline.h"
+#include "vtkStringStream.h"
 
 #include <sys/stat.h>
 #include <assert.h>
@@ -76,6 +77,8 @@
   this->TimeSteps = 0;
   this->CurrentTimeStep = 0;
   this->TimeStepWasReadOnce = 0;
+
+  this->StringStream = NULL;
 }
 
 //----------------------------------------------------------------------------
@@ -1197,3 +1200,26 @@
   return 0;
 }
 
+
+void vtkXMLReader::SetStringStream(vtkStringStream *ss)
+{
+  if (this->StringStream)
+    {
+    //Decrement the ref count
+    this->StringStream->Delete();
+    }
+  if (ss != NULL)
+    {
+    this->StringStream = ss;
+    this->StringStream->Register(this);
+    this->Modified();
+    this->Stream = this->StringStream->GetStream();
+    }
+  else 
+    {
+    // setting StringStream to NULL, will cause reader to read from disk again.
+    this->StringStream = NULL;
+    this->Stream = NULL;
+    }
+
+}
Index: vtkXMLReader.h
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/vtkXMLReader.h,v
retrieving revision 1.20
diff -u -r1.20 vtkXMLReader.h
--- vtkXMLReader.h	5 Jan 2006 18:29:04 -0000	1.20
+++ vtkXMLReader.h	25 Jun 2007 15:11:30 -0000
@@ -31,6 +31,7 @@
 class vtkXMLDataElement;
 class vtkXMLDataParser;
 class vtkInformationVector;
+class vtkStringStream;
 
 class VTK_IO_EXPORT vtkXMLReader : public vtkAlgorithm
 {
@@ -94,6 +95,11 @@
   vtkGetVector2Macro(TimeStepRange, int);
   vtkSetVector2Macro(TimeStepRange, int);
 
+  // Description:
+  // Set/Get the string stream to use instead of a file
+  void SetStringStream(vtkStringStream *ss);
+  vtkGetObjectMacro(StringStream, vtkStringStream);
+
 protected:
   vtkXMLReader();
   ~vtkXMLReader();
@@ -186,6 +192,9 @@
   
   // The stream used to read the input.
   istream* Stream;
+
+  // The string stream to use instead of a file
+  vtkStringStream *StringStream;
   
   // The array selections.
   vtkDataArraySelection* PointDataArraySelection;
Index: vtkXMLWriter.cxx
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/vtkXMLWriter.cxx,v
retrieving revision 1.71
diff -u -r1.71 vtkXMLWriter.cxx
--- vtkXMLWriter.cxx	10 Apr 2007 18:02:31 -0000	1.71
+++ vtkXMLWriter.cxx	1 Jul 2007 21:54:30 -0000
@@ -31,6 +31,7 @@
 #include "vtkStreamingDemandDrivenPipeline.h"
 #include "vtkUnsignedCharArray.h"
 #include "vtkZLibDataCompressor.h"
+#include "vtkStringStream.h"
 #define vtkOffsetsManager_DoNotInclude
 #include "vtkOffsetsManagerArray.h"
 #undef  vtkOffsetsManager_DoNotInclude
@@ -260,6 +261,8 @@
   this->UserContinueExecuting = -1; //invalid state
   this->NumberOfTimeValues = NULL;
   this->FieldDataOM = new OffsetsManagerGroup;
+
+  this->StringStream = NULL;
 }
 
 //----------------------------------------------------------------------------
@@ -547,8 +550,14 @@
   this->OutFile = 0;
   if(this->Stream)
     {
-    // Rewind stream to the beginning.
-    this->Stream->seekp(0);
+    // Reset and rewind stream to the beginning.
+    if (this->Stream->tellp() > 0)
+      {
+      vtksys_ios::stringstream *ss = dynamic_cast<vtksys_ios::stringstream *> (this->Stream);
+      ss->seekp(0);
+      ss->str("");
+      }
+
     }
   else
     {
@@ -593,11 +602,12 @@
 //----------------------------------------------------------------------------
 void vtkXMLWriter::CloseFile()
 {
-  // Cleanup the output streams.
-  this->DataStream->SetStream(0);
 
   if(this->OutFile)
     {
+    // Cleanup the output streams.
+    this->DataStream->SetStream(0);
+
     // We opened a file.  Close it.
     delete this->OutFile;
     this->OutFile = 0;
@@ -2875,4 +2885,28 @@
     }
 }
 
+void vtkXMLWriter::SetStringStream(vtkStringStream *ss)
+{
+  if (this->StringStream)
+    {
+    //Decrement the ref count
+    this->StringStream->Delete();
+    }
+
+  if (ss != NULL)
+    {
+    this->StringStream = ss;
+    this->StringStream->Register(this);
+    this->Modified();
+    this->Stream = this->StringStream->GetStream();
+    }
+  else
+    {
+    // setting StringStream to NULL, will cause writer to write to disk again.
+    this->StringStream = NULL;
+    this->Stream = NULL;
+    }
+
 
+
+}
Index: vtkXMLWriter.h
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/vtkXMLWriter.h,v
retrieving revision 1.25
diff -u -r1.25 vtkXMLWriter.h
--- vtkXMLWriter.h	5 Jan 2006 18:29:05 -0000	1.25
+++ vtkXMLWriter.h	25 Jun 2007 15:13:30 -0000
@@ -38,6 +38,7 @@
 class vtkPointData;
 class vtkPoints;
 class vtkFieldData;
+class vtkStringStream;
 //BTX
 class vtkStdString;
 class OffsetsManager;      // one per piece/per time
@@ -180,6 +181,11 @@
   void Stop();
   void WriteNextTime(double time);
 
+  // Description:
+  // Set/Get the string stream to use instead of a file
+  void SetStringStream(vtkStringStream *ss);
+  vtkGetObjectMacro(StringStream, vtkStringStream);
+
 protected:
   vtkXMLWriter();
   ~vtkXMLWriter();
@@ -434,6 +440,8 @@
   friend class vtkXMLWriterHelper;
   //ETX
 
+  vtkStringStream *StringStream;
+
 private:
   vtkXMLWriter(const vtkXMLWriter&);  // Not implemented.
   void operator=(const vtkXMLWriter&);  // Not implemented.

? vtkStringStream.cxx
? vtkStringStream.h
? vtkXMLWriter.cxx.1
? vtkXMLWriter.h.1
? Testing/Tcl/mhdWriter.mhd
? Testing/Tcl/mhdWriter.raw
Index: CMakeLists.txt
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/CMakeLists.txt,v
retrieving revision 1.157
diff -u -r1.157 CMakeLists.txt
--- CMakeLists.txt	10 May 2007 17:14:11 -0000	1.157
+++ CMakeLists.txt	1 Jul 2007 22:06:12 -0000
@@ -93,6 +93,7 @@
 vtkSLCReader.cxx
 vtkSTLReader.cxx
 vtkSTLWriter.cxx
+vtkStringStream.cxx
 vtkSimplePointsReader.cxx
 vtkSortFileNames.cxx
 vtkStructuredGridReader.cxx
Index: vtkXMLReader.cxx
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/vtkXMLReader.cxx,v
retrieving revision 1.45
diff -u -r1.45 vtkXMLReader.cxx
--- vtkXMLReader.cxx	15 Feb 2007 21:04:23 -0000	1.45
+++ vtkXMLReader.cxx	3 Jul 2007 13:39:40 -0000
@@ -28,6 +28,7 @@
 #include "vtkInformation.h"
 #include "vtkInformationVector.h"
 #include "vtkStreamingDemandDrivenPipeline.h"
+#include "vtkStringStream.h"
 
 #include <sys/stat.h>
 #include <assert.h>
@@ -76,6 +77,8 @@
   this->TimeSteps = 0;
   this->CurrentTimeStep = 0;
   this->TimeStepWasReadOnce = 0;
+
+  this->StringStream = NULL;
 }
 
 //----------------------------------------------------------------------------
@@ -92,6 +95,13 @@
   this->CellDataArraySelection->Delete();
   this->PointDataArraySelection->Delete();
   delete[] this->TimeSteps;
+
+  if (this->StringStream)
+    {
+    this->StringStream->SetReader(NULL);
+    this->StringStream = NULL;
+    this->Stream = NULL;
+    }
 }
 
 //----------------------------------------------------------------------------
@@ -1197,3 +1207,24 @@
   return 0;
 }
 
+
+void vtkXMLReader::SetStringStream(vtkStringStream *ss)
+{
+
+  if (ss != NULL)
+    {
+    this->StringStream = ss;
+    this->StringStream->Register(this);
+    this->Modified();
+    this->Stream = this->StringStream->GetStream();
+    this->StringStream->SetReader(this);
+    }
+  else 
+    {
+    // setting StringStream to NULL, will cause reader to read from disk again.
+    this->StringStream->SetReader(NULL);
+    this->StringStream = NULL;
+    this->Stream = NULL;
+    }
+
+}
Index: vtkXMLReader.h
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/vtkXMLReader.h,v
retrieving revision 1.20
diff -u -r1.20 vtkXMLReader.h
--- vtkXMLReader.h	5 Jan 2006 18:29:04 -0000	1.20
+++ vtkXMLReader.h	25 Jun 2007 15:11:30 -0000
@@ -31,6 +31,7 @@
 class vtkXMLDataElement;
 class vtkXMLDataParser;
 class vtkInformationVector;
+class vtkStringStream;
 
 class VTK_IO_EXPORT vtkXMLReader : public vtkAlgorithm
 {
@@ -94,6 +95,11 @@
   vtkGetVector2Macro(TimeStepRange, int);
   vtkSetVector2Macro(TimeStepRange, int);
 
+  // Description:
+  // Set/Get the string stream to use instead of a file
+  void SetStringStream(vtkStringStream *ss);
+  vtkGetObjectMacro(StringStream, vtkStringStream);
+
 protected:
   vtkXMLReader();
   ~vtkXMLReader();
@@ -186,6 +192,9 @@
   
   // The stream used to read the input.
   istream* Stream;
+
+  // The string stream to use instead of a file
+  vtkStringStream *StringStream;
   
   // The array selections.
   vtkDataArraySelection* PointDataArraySelection;
Index: vtkXMLWriter.cxx
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/vtkXMLWriter.cxx,v
retrieving revision 1.71
diff -u -r1.71 vtkXMLWriter.cxx
--- vtkXMLWriter.cxx	10 Apr 2007 18:02:31 -0000	1.71
+++ vtkXMLWriter.cxx	3 Jul 2007 13:38:32 -0000
@@ -31,6 +31,7 @@
 #include "vtkStreamingDemandDrivenPipeline.h"
 #include "vtkUnsignedCharArray.h"
 #include "vtkZLibDataCompressor.h"
+#include "vtkStringStream.h"
 #define vtkOffsetsManager_DoNotInclude
 #include "vtkOffsetsManagerArray.h"
 #undef  vtkOffsetsManager_DoNotInclude
@@ -260,6 +261,8 @@
   this->UserContinueExecuting = -1; //invalid state
   this->NumberOfTimeValues = NULL;
   this->FieldDataOM = new OffsetsManagerGroup;
+
+  this->StringStream = NULL;
 }
 
 //----------------------------------------------------------------------------
@@ -272,6 +275,13 @@
 
   delete this->FieldDataOM;
   delete[] this->NumberOfTimeValues;
+
+  if (this->StringStream)
+    {
+    this->StringStream->SetWriter(NULL);
+    this->StringStream = NULL;
+    this->Stream = NULL;
+    }
 }
 
 //----------------------------------------------------------------------------
@@ -547,8 +557,12 @@
   this->OutFile = 0;
   if(this->Stream)
     {
-    // Rewind stream to the beginning.
-    this->Stream->seekp(0);
+    // Reset and rewind stream to the beginning.
+    if (this->Stream->tellp() > 0)
+      {
+      this->StringStream->Reset();
+      }
+
     }
   else
     {
@@ -593,11 +607,12 @@
 //----------------------------------------------------------------------------
 void vtkXMLWriter::CloseFile()
 {
-  // Cleanup the output streams.
-  this->DataStream->SetStream(0);
 
   if(this->OutFile)
     {
+    // Cleanup the output streams.
+    this->DataStream->SetStream(0);
+
     // We opened a file.  Close it.
     delete this->OutFile;
     this->OutFile = 0;
@@ -2875,4 +2890,24 @@
     }
 }
 
+void vtkXMLWriter::SetStringStream(vtkStringStream *ss)
+{
 
+  if (ss != NULL)
+    {
+    this->StringStream = ss;
+    this->Modified();
+    this->Stream = this->StringStream->GetStream();
+    this->StringStream->SetWriter(this);
+    }
+  else
+    {
+    // setting StringStream to NULL, will cause writer to write to disk again.
+    this->StringStream->SetWriter(NULL);
+    this->StringStream = NULL;
+    this->Stream = NULL;
+    }
+
+
+
+}
Index: vtkXMLWriter.h
===================================================================
RCS file: /cvsroot/VTK/VTK/IO/vtkXMLWriter.h,v
retrieving revision 1.25
diff -u -r1.25 vtkXMLWriter.h
--- vtkXMLWriter.h	5 Jan 2006 18:29:05 -0000	1.25
+++ vtkXMLWriter.h	25 Jun 2007 15:13:30 -0000
@@ -38,6 +38,7 @@
 class vtkPointData;
 class vtkPoints;
 class vtkFieldData;
+class vtkStringStream;
 //BTX
 class vtkStdString;
 class OffsetsManager;      // one per piece/per time
@@ -180,6 +181,11 @@
   void Stop();
   void WriteNextTime(double time);
 
+  // Description:
+  // Set/Get the string stream to use instead of a file
+  void SetStringStream(vtkStringStream *ss);
+  vtkGetObjectMacro(StringStream, vtkStringStream);
+
 protected:
   vtkXMLWriter();
   ~vtkXMLWriter();
@@ -434,6 +440,8 @@
   friend class vtkXMLWriterHelper;
   //ETX
 
+  vtkStringStream *StringStream;
+
 private:
   vtkXMLWriter(const vtkXMLWriter&);  // Not implemented.
   void operator=(const vtkXMLWriter&);  // Not implemented.