substringdata.h

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  *
  * Idea for the future to  maybe implement:
  * add hooks to GeneralData, like
  * virtual void hookBeforeCreate(Txnid *) and
  * virtual void hookBeforeRemove(Txnid *).  
  * Database::Creator would then call these hooks everytime a 
  * create or remove is to be done.
  * We would now have the possibility to add substring search functionality for the
  * dna sequence in the DnaStrData feature.
  * We implement a new Class,   SubStrData : public GeneralData that stores e.g. sequences 
  * of length 12. 
  * The DnaStrData::hookBeforeCreate(Txnid *) creates each possible 12-length-substring as records
  * in the SubStrData.
  * The SubStrData::getIndex() should return two secondary indices: one with sorting of the DnaStrData recno,
  * and one with sorting in lexicographical order of the 12-length-substring


class SubStrData : public GeneralData
{
 public:
  virtual TrDb::IndexMap GeneralData::getIndexMap()
    { 
    TrDb::IndexMap iMap;
    TrDb::Index i = {
      &SubStrData::bt_compare_dnaStrRecNo,
      &SubStrData::getDnaStrRecNo,
      QString("dnaStrRecno"),
                        NULL
    };
    iMap.insert( make_pair( i.name, i ) );
    i = {
      &SubStrData::bt_compare_subStr,
      &SubStrData::getSubStr,
      QString("substring"),
                      NULL
    };
    iMap.insert( make_pair( i.name, i ) );
    return iMap;
  }

  int getDnaStrRecNo( Db * /* dbp */ , const Dbt *  /* pkey */, const Dbt *pdata, Dbt *skey)
    {
      memset(skey, 0, sizeof(Dbt));
      StorageData * data = ( StorageData * ) pdata->get_data();
      skey->set_data( ( u_int8_t * ) (& (data->dnastrdataRecno)) );
      skey->set_size(sizeof( db_recno_t ));
      return(0);
    }
    struct StorageData
    {
      char[12] substring;
      db_recno_t dnastrdataRecno;
    };


    int bt_compare_dnaStrRecNo( DB * , const DBT *dbt1, const DBT *dbt2)
      {
        /* order after row and then after end position */
        db_recno_t * recno1  = ( db_recno_t *) dbt1->data;
        db_recno_t * recno2  = ( db_recno_t *) dbt2->data;
        if ( *recno1 > *recno2 )
          return 1;
        if ( *recno1 < *recno2 )
          return -1;
        if ( *recno1 == *recno2 )
          return 0;
        /* should never reach this point */
        return 0;
      }

  db_recno_t dnastrdataRecno;
 protected:
    std::string substr;
};

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