#ifndef TMidasTripTOldHistoItr_hxx_seen
#define TMidasTripTOldHistoItr_hxx_seen
// $Id: IMidasTripTOldHistoItr.hxx,v 1.2 2009/09/25 06:02:32 nickwest Exp $
//

// The ProHisto class is for the prototype histogram bank used in the first implementation
// of the DPT.  The ITripTHistoBank and IMidasTripTHisto banks are used for the new
// version of the DPT (developed in July 2009, installed a month or two later).

#include <IMidasObj.hxx>
#include "IMidasItr.hxx"
#include "IMidasTripTOldHisto.hxx"

namespace COMET {
    class ITripTOldHistoBank;
    class IMidasTripTOldHisto;
    class IMidasTripTOldHistoItr;
};

/// The class provides forward iteration over all the TMidasTripTOldHistos in a
/// ITripTOldHistoBank.  It skips discretely over empty slots in the bank

class COMET::IMidasTripTOldHistoItr: public COMET::IMidasItr<COMET::IMidasTripTOldHisto> {

public:
    IMidasTripTOldHistoItr(const COMET::ITripTOldHistoBank* parent);
    virtual ~IMidasTripTOldHistoItr() {}

protected:

    /// Implement method mandated by IMidasItr.
    virtual Bool_t EODImp() const { return (fSlotNext == fSlotEOD); }
    /// Implement method mandated by IMidasItr.
    virtual IMidasTripTOldHisto GetImp();
    /// Implement method mandated by IMidasItr.
    virtual void RewindImp() {
          fDataNext = fDataStart;
          fSlotNext = fSlotStart;
    };

private:
    /// The state of this iterator is captured in fSlotNext which
    /// is the next location in the index.    However, the pointer 
    /// fDataNext (which goes between fDataStart and fDataEOD) 
    /// is also held current. 

    const COMET::ITripTOldHistoBank * const fParent;  // Ptr to the parent bank
    const UShort_t * const fPtrStart;  /// Ptr to table of the slots in the bank
    const UChar_t * const fDataStart;  /// Ptr to first IMidasTripTOldHisto in data of parent ITripTOldHistoBank.
    const UChar_t * const fDataEOD;    /// Ptr to end of data (= end of the parent ITripTOldHistoBank).
    const UChar_t *fDataNext;   /// Ptr to IMidasTripTOldHisto in data ITripTOldHistoBank returned by next call to GetImp()

    const UInt_t fSlotStart;  /// Index to the slot number we start with
    UInt_t fSlotNext;         /// Index to the slot number next
    const UInt_t fSlotEOD;    /// Last slot number +1 (= number of slots)

};
#endif