From 3ca30736b473b922e199fb0c0173ccbaee4b531b Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 24 Feb 2012 11:43:35 +0000
Subject: [PATCH] Added support for checking the possible endian reversal the
 OSG_HEADER_LOW and OSG_HEADER_HIGH when reading binary files written out from
 systems that have a different endian to the system reading it.

---
 src/osgPlugins/osg/BinaryStreamOperator.h |  4 ++--
 src/osgPlugins/osg/ReaderWriterOSG2.cpp   | 11 ++++++++++-
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/osgPlugins/osg/BinaryStreamOperator.h b/src/osgPlugins/osg/BinaryStreamOperator.h
index b8f140141..7cfa1ca09 100644
--- a/src/osgPlugins/osg/BinaryStreamOperator.h
+++ b/src/osgPlugins/osg/BinaryStreamOperator.h
@@ -73,7 +73,7 @@ public:
 class BinaryInputIterator : public osgDB::InputIterator
 {
 public:
-    BinaryInputIterator( std::istream* istream ) : _byteSwap(0) { _in = istream; }
+    BinaryInputIterator( std::istream* istream, bool byteSwap ) : _byteSwap(byteSwap) { _in = istream; }
     virtual ~BinaryInputIterator() {}
     
     virtual bool isBinary() const { return true; }
@@ -188,7 +188,7 @@ public:
     { readString( str ); }
     
 protected:
-    int _byteSwap;
+    bool _byteSwap;
 };
 
 #endif
diff --git a/src/osgPlugins/osg/ReaderWriterOSG2.cpp b/src/osgPlugins/osg/ReaderWriterOSG2.cpp
index 542265e3f..990e31bba 100644
--- a/src/osgPlugins/osg/ReaderWriterOSG2.cpp
+++ b/src/osgPlugins/osg/ReaderWriterOSG2.cpp
@@ -26,6 +26,8 @@ using namespace osgDB;
 #define CATCH_EXCEPTION(s) \
     if (s.getException()) return (s.getException()->getError() + " At " + s.getException()->getField());
 
+#define OSG_REVERSE(value) ( ((value & 0x000000ff)<<24) | ((value & 0x0000ff00)<<8) | ((value & 0x00ff0000)>>8) | ((value & 0xff000000)>>24) )
+
 InputIterator* readInputIterator( std::istream& fin, const Options* options )
 {
     bool extensionIsAscii = false, extensionIsXML = false;
@@ -43,8 +45,15 @@ InputIterator* readInputIterator( std::istream& fin, const Options* options )
         fin.read( (char*)&headerHigh, INT_SIZE );
         if ( headerLow==OSG_HEADER_LOW && headerHigh==OSG_HEADER_HIGH )
         {
-            return new BinaryInputIterator(&fin);
+            OSG_INFO<<"Reading OpenSceneGraph binary file with the same endian as this computer."<<std::endl;
+            return new BinaryInputIterator(&fin, false); // endian the same so no byte swap required
         }
+        else if ( headerLow==OSG_REVERSE(OSG_HEADER_LOW) && headerHigh==OSG_REVERSE(OSG_HEADER_HIGH) )
+        {
+            OSG_INFO<<"Reading OpenSceneGraph binary file with the different endian to this computer, doing byte swap."<<std::endl;
+            return new BinaryInputIterator(&fin, true); // endian different so byte swap required
+        }
+        
         fin.seekg( 0, std::ios::beg );
     }