diff --git a/contrib/addtiffo/tif_overview.c b/contrib/addtiffo/tif_overview.c
index 83313abf..65f6e3b5 100644
--- a/contrib/addtiffo/tif_overview.c
+++ b/contrib/addtiffo/tif_overview.c
@@ -1,5 +1,5 @@
 /******************************************************************************
- * $Id: tif_overview.c,v 1.6 2004-08-08 15:32:29 dron Exp $
+ * tif_overview.c,v 1.9 2005/05/25 09:03:16 dron Exp
  *
  * Project:  TIFF Overview Builder
  * Purpose:  Library function for building overviews in a TIFF file.
@@ -53,6 +53,10 @@
 #include "tiffio.h"
 #include "tif_ovrcache.h"
 
+#include "cpl_port.h"
+
+CPL_CVSID("tif_overview.c,v 1.2 2001/07/18 04:51:56 warmerda Exp");
+
 #ifndef FALSE
 #  define FALSE 0
 #  define TRUE 1
@@ -76,7 +80,7 @@ void TIFFBuildOverviews( TIFF *, int, int *, int, const char *,
 /************************************************************************/
 
 uint32 TIFF_WriteOverview( TIFF *hTIFF, int nXSize, int nYSize,
-                           int nBitsPerPixel, int nSamples, 
+                           int nBitsPerPixel, int nPlanarConfig, int nSamples, 
                            int nBlockXSize, int nBlockYSize,
                            int bTiled, int nCompressFlag, int nPhotometric,
                            int nSampleFormat,
@@ -101,7 +105,7 @@ uint32 TIFF_WriteOverview( TIFF *hTIFF, int nXSize, int nYSize,
     if( nSamples == 1 )
         TIFFSetField( hTIFF, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG );
     else
-        TIFFSetField( hTIFF, TIFFTAG_PLANARCONFIG, PLANARCONFIG_SEPARATE );
+        TIFFSetField( hTIFF, TIFFTAG_PLANARCONFIG, nPlanarConfig );
 
     TIFFSetField( hTIFF, TIFFTAG_BITSPERSAMPLE, nBitsPerPixel );
     TIFFSetField( hTIFF, TIFFTAG_SAMPLESPERPIXEL, nSamples );
@@ -531,14 +535,15 @@ void TIFFBuildOverviews( TIFF *hTIFF, int nOverviews, int * panOvList,
                       &panRedMap, &panGreenMap, &panBlueMap ) )
     {
         uint16		*panRed2, *panGreen2, *panBlue2;
+        int             nColorCount = 1 << nBitsPerPixel;
 
-        panRed2 = (uint16 *) _TIFFmalloc(2*256);
-        panGreen2 = (uint16 *) _TIFFmalloc(2*256);
-        panBlue2 = (uint16 *) _TIFFmalloc(2*256);
+        panRed2 = (uint16 *) _TIFFmalloc(2*nColorCount);
+        panGreen2 = (uint16 *) _TIFFmalloc(2*nColorCount);
+        panBlue2 = (uint16 *) _TIFFmalloc(2*nColorCount);
 
-        memcpy( panRed2, panRedMap, 512 );
-        memcpy( panGreen2, panGreenMap, 512 );
-        memcpy( panBlue2, panBlueMap, 512 );
+        memcpy( panRed2, panRedMap, 2 * nColorCount );
+        memcpy( panGreen2, panGreenMap, 2 * nColorCount );
+        memcpy( panBlue2, panBlueMap, 2 * nColorCount );
 
         panRedMap = panRed2;
         panGreenMap = panGreen2;
@@ -575,8 +580,8 @@ void TIFFBuildOverviews( TIFF *hTIFF, int nOverviews, int * panOvList,
         }
 
         nDirOffset = TIFF_WriteOverview( hTIFF, nOXSize, nOYSize,
-                                         nBitsPerPixel, nSamples,
-                                         nOBlockXSize, nOBlockYSize,
+                                         nBitsPerPixel, nPlanarConfig,
+                                         nSamples, nOBlockXSize, nOBlockYSize,
                                          bTiled, nCompressFlag, nPhotometric,
                                          nSampleFormat,
                                          panRedMap, panGreenMap, panBlueMap,
diff --git a/contrib/addtiffo/tif_ovrcache.h b/contrib/addtiffo/tif_ovrcache.h
index 99961570..f0775cf9 100644
--- a/contrib/addtiffo/tif_ovrcache.h
+++ b/contrib/addtiffo/tif_ovrcache.h
@@ -1,5 +1,5 @@
 /******************************************************************************
- * $Id: tif_ovrcache.h,v 1.1 2000-01-28 15:03:32 warmerda Exp $
+ * tif_ovrcache.h,v 1.3 2005/05/25 09:03:16 dron Exp
  *
  * Project:  TIFF Overview Builder
  * Purpose:  Library functions to maintain two rows of tiles or two strips
@@ -30,16 +30,17 @@
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  ******************************************************************************
- *
- * $Log: tif_ovrcache.h,v $
- * Revision 1.1  2000-01-28 15:03:32  warmerda
- * New
- *
  */
 
 #ifndef TIF_OVRCACHE_H_INCLUDED
 #define TIF_OVRCACHE_H_INCLUDED
 
+#include "tiffio.h"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+    
 typedef struct 
 {
     uint32	nXSize;
@@ -68,5 +69,25 @@ TIFFOvrCache *TIFFCreateOvrCache( TIFF *hTIFF, int nDirOffset );
 unsigned char *TIFFGetOvrBlock( TIFFOvrCache *, int, int, int );
 void           TIFFDestroyOvrCache( TIFFOvrCache * );
 
+void TIFFBuildOverviews( TIFF *, int, int *, int, const char *,
+                         int (*)(double,void*), void * );
+
+void TIFF_ProcessFullResBlock( TIFF *hTIFF, int nPlanarConfig,
+                               int nOverviews, int * panOvList,
+                               int nBitsPerPixel, 
+                               int nSamples, TIFFOvrCache ** papoRawBIs,
+                               int nSXOff, int nSYOff,
+                               unsigned char *pabySrcTile,
+                               int nBlockXSize, int nBlockYSize,
+                               int nSampleFormat, const char * pszResampling );
+
+uint32 TIFF_WriteOverview( TIFF *, int, int, int, int, int, int, int,
+                           int, int, int, int, unsigned short *,
+                           unsigned short *, unsigned short *, int );
+
+#if defined(__cplusplus)
+}
+#endif
+    
 #endif /* ndef TIF_OVRCACHE_H_INCLUDED */