Index: trunk/Ohana/src/libfits/include/gfitsio.h
===================================================================
--- trunk/Ohana/src/libfits/include/gfitsio.h	(revision 35101)
+++ trunk/Ohana/src/libfits/include/gfitsio.h	(revision 35162)
@@ -123,4 +123,5 @@
 off_t   gfits_data_size                PROTO((Header *header));
 off_t   gfits_data_min_size            PROTO((Header *header));
+off_t   gfits_data_pad_size            PROTO((off_t rawsize));
 int 	gfits_extended_to_primary      PROTO((Header *header, int simple, char *comment));
 int 	gfits_primary_to_extended      PROTO((Header *header, char *exttype, char *comment));
Index: trunk/Ohana/src/libfits/matrix/F_matrix.c
===================================================================
--- trunk/Ohana/src/libfits/matrix/F_matrix.c	(revision 35101)
+++ trunk/Ohana/src/libfits/matrix/F_matrix.c	(revision 35162)
@@ -43,2 +43,15 @@
   return (size);
 }
+
+off_t gfits_data_pad_size (off_t rawsize) {
+  
+  off_t Nrec, size;
+
+  /* round up to next complete block */
+  if (rawsize % FT_RECORD_SIZE) {
+    Nrec = 1 + (int) (rawsize / FT_RECORD_SIZE);
+    size = FT_RECORD_SIZE * Nrec;
+  }
+
+  return (size);
+}