RingBuffer.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <sys/ipc.h>
#include <string>
 
namespace Belle2 {

  struct RingBufInfo {
    int size; 
    int remain; 
    int wptr; 
    int prevwptr; 
    int rptr; 
    int nbuf; 
    int semid; 
    int nattached; 
    int nbusy; 
    int __readbuf; 
    int errtype; 
    int numAttachedTx; 
    int ninsq; 
    int nremq; 
  };

  class RingBuffer {
  public:
    const static int c_DefaultSize = 15000000;

    explicit RingBuffer(int nwords = c_DefaultSize);
    explicit RingBuffer(const std::string& name, unsigned int nwords = 0);     // Create / Attach Ring buffer
    ~RingBuffer();
    void openSHM(int nwords);
    void cleanup();

    int insq(const int* buf, int size, bool checkTx = false);
    int remq(int* buf, int capacityWords = -1);
    int spyq(int* buf) const;
    int numq() const;

    void txAttached();
    void txDetached();
    void kill();

    bool isDead() const;
    bool allRxWaiting() const;

    int clear();
    void forceClear();

    int tryClear();

    int shmid() const;
 
    // Debugging functions
    void dump_db();
    int ninsq() const;
    int nremq() const;

    int insq_counter() const;
    int remq_counter() const;

    void dumpInfo() const;
 
  private:
    bool m_new{true}; 
    bool m_file{false}; 
    std::string m_pathname{""}; 
    int  m_pathfd{ -1}; 
    key_t m_shmkey{IPC_PRIVATE}; 
    key_t m_semkey{IPC_PRIVATE}; 
    std::string m_semshmFileName{""};

    bool m_procIsBusy{false};
 
    int  m_shmid{ -1}; 
    int* m_shmadr{nullptr}; 
    int  m_shmsize{ -1}; 
    struct RingBufInfo* m_bufinfo {nullptr}; 
    int* m_buftop{nullptr}; 
    int  m_semid{ -1}; 
    int  m_remq_counter{0}; 
    int  m_insq_counter{0}; 
  };

}