Section 428 of the Criminal Procedure Code

Period of detention undergone by the accuser to be set off against the sentence of imprisonment:

Where an accused person has, on conviction, been sentenced to imprisonment for a term, not being imprisonment in default of payment of fine, the period of detention, if any undergone by him during the investigation, inquiry or trial of the same case and before the date of such conviction, shall be set off against the term of imprisonment imposed on him on such conviction, and the liability of such person to undergo imprisonment on such conviction shall be restricted to the remainder, if any, of the term of imprisonment imposed on him.