fix copying RageFileDriverSlice doesn't init RageFileObj properly, causing desync between file pointers (RageFileObj thinks it's at 0, RageFileDriverSlice thinks it's at somewhere else)

stepmania/src/RageFileDriverSlice.cpp

@@ -10,6 +10,16 @@ RageFileDriverSlice::RageFileDriverSlice( RageFileBasic *pFile, int iOffset, int
 	m_bFileOwned = false;
 }
 
+RageFileDriverSlice::RageFileDriverSlice( const RageFileDriverSlice &cpy ):
+	RageFileObj(cpy)
+{
+	m_pFile = cpy.m_pFile->Copy();
+	m_iOffset = cpy.m_iOffset;
+	m_iFileSize = cpy.m_iFileSize;
+	m_iFilePos = cpy.m_iFilePos;
+	m_bFileOwned = true;
+}
+
 RageFileDriverSlice::~RageFileDriverSlice()
 {
 	if( m_bFileOwned )
@@ -18,9 +28,7 @@ RageFileDriverSlice::~RageFileDriverSlice()
 
 RageFileBasic *RageFileDriverSlice::Copy() const
 {
-	RageFileDriverSlice *pRet = new RageFileDriverSlice( m_pFile->Copy(), m_iOffset, m_iFileSize );
+	RageFileDriverSlice *pRet = new RageFileDriverSlice( *this );
-	pRet->m_bFileOwned = true;
-	pRet->m_iFilePos = m_iFilePos;
 	return pRet;
 }
 

stepmania/src/RageFileDriverSlice.h

@@ -8,8 +8,9 @@
 class RageFileDriverSlice: public RageFileObj
 {
 public:
-	/* pFile will be freed. */
+	/* pFile will be freed if DeleteFileWhenFinished is called. */
 	RageFileDriverSlice( RageFileBasic *pFile, int iOffset, int iFileSize );
+	RageFileDriverSlice( const RageFileDriverSlice &cpy );
 	~RageFileDriverSlice();
 	RageFileBasic *Copy() const;