question: private void blockCopyLinesDown ( int srcInternal , int len ) { if ( len == 0 ) return ; int totalRows = mTotalRows ; int start = len - 1 ; TerminalRow lineToBeOverWritten = mLines [ ( srcInternal + start + 1 ) % totalRows ] ; for ( int i = start ; i >= 0 ; -- i ) mLines [ ( srcInternal + i + 1 ) % totalRows ] = mLines [ ( srcInternal + i ) % totalRows ] ; mLines [ ( srcInternal ) % totalRows ] = lineToBeOverWritten ; }
target:  Block copy lines and associated metadata from one location to another in the circular buffer, taking wraparound into account.