Issue with internal table columns

Hi All,

I got an issue while working with internal tables.

I am trying to create an output table from input table based on the customized mapping table. Mapping table records  will be like this

  inputfld    outputfld

  COL1         COL3

  COL4         COL1

  COL3         COL2

here, From my input table(itab1) COL1 data should map to output Table ( Itab2) COL3, similarly for itab1-COL4 should map to itab2-COL1.

Mapping should be based on customized mapping table ZMAP.

Is there any Idea to achive this.

Please help .

Thanks,

Vishnu