EvtIdxHandler.h

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#ifndef BESIII_EVTIDX_HANDLER_H
#define BESIII_EVTIDX_HANDLER_H
 
#include <vector>
#include <string>
#include <fstream>
 
class EvtIdxHandler
{
   public :
 
      static uint32_t IdxFileStartMarker() { return 0xFFFFAAAA; }
      static uint32_t IdxIdBlockMarker()   { return 0xFFFFBBBB; }
      static uint32_t IdxPosBlockMarker()  { return 0xFFFFCCCC; }
 
      static EvtIdxHandler* instance(const std::vector<std::string>& fnames);
      static void release();
 
      EvtIdxHandler();  // writing
      virtual ~EvtIdxHandler();
 
      // for reading
      void next_file();
 
      uint32_t  nextPos(int nIgnore);
      uint32_t  findPosById(uint32_t evtId);
 
      int nEvtLeft(int nIgnore) const {
     return ( m_totEvt - (m_idxPos+nIgnore) );
      }
 
      // for constructing and writing
      void addPos(uint32_t evtId, uint32_t pos);
      void write(std::string fname);
 
 
   private :
 
      EvtIdxHandler(const std::vector<std::string>& idxfnames);  // reading
 
      void init_idx();  //only for reading
      void enlarge_block(int min_size);
 
 
   private :
 
      int        m_totEvt;
      int        m_idxPos;  //only for reading, no less than 0
 
      int        m_blockSize;
      uint32_t*  m_EIdBlock;
      uint32_t*  m_PosBlock;
 
      std::vector<std::string>            m_fnames;  //only for reading
      std::vector<std::string>::iterator  m_curFile;  //only for reading
      std::fstream                        m_fs;
 
      static int             _nHandler;
      static EvtIdxHandler*  _instance;
};
 
#endif