add additional check on fullSize

DaqFileIO.cxx

@@ -2,7 +2,7 @@
 ///
 // DAQ low level IO Library
 // 
-// $Id: DaqFileIO.cxx,v 1.22 2016/04/19 20:53:03 iowa\cschwarz Exp $
+// $Id: DaqFileIO.cxx,v 1.23 2016/04/19 21:05:50 iowa\cschwarz Exp $
 // Date: March, 2005
 // Author: Yiannis Papelis
 //
@@ -1303,7 +1303,7 @@ CDaqLowLevelIo::LowLevelDataRead(
 				// The shorter storage used in the DAQ is transparent to the user so we fill
 				// the rest of the space (that didn't get read from the file with zeros.
 				int fullSize = ch.GetRecSize();
-				if ( fullSize  != size ) {
+				if ( fullSize != size && size < fullSize ) {
 					memset(((char *)pTempSpace) + size, 0, fullSize - size);
 				}
 				daqBuf.Append(pTempSpace, fullSize, ch.GetItemCount());
@@ -1967,7 +1967,7 @@ CDaqLowLevelIo::ReadChannelDataForOneFrame(
 			}
 
 			int fullSize = ch.GetRecSize();
-			if ( fullSize != size ) {
+			if ( fullSize != size && size < fullSize ) {
 				memset(((char *)pTempSpace) + size, 0, fullSize - size);
 			}
 			daqBuf.Replace(pTempSpace, fullSize, ch.GetItemCount());