Filling calday - Help with ABAP code

I have a flat file of the below structure  with about 50 rows .Each row has a different Code(this is the main field).  There are flat files for differrent years like one flat file for year 2011, one for 2012, and so on..

The above flat file content that I have pasted is for year 2013 Whcih means the calender year field is 2013 for all rows in this file. I am loading flat files to a DSO

There is a field called New date in my DSO. It s is  a blank field now . I need to populate this field  During the load from flat file to DSO in either my start routine/field routine .

For eg., for Code C1 there will be only 1 entry in the flat file. I need to populate 365 entries in the DSO .i.e., the new date should have entries from 01.01.2013 until 31.12.2013 (full year dates).. For every code , the new dates should be populated in my DSO . the final entry in my DSo would look like

Similarly  the next code should have 365 entries in DSO and so on until the last code in my flat file.

BAsicallly every code in my DSO should have 365 entries which came from one entry in flat file..

Help with ABAP code please?