Line data    Source code

       1             : /*
       2             :  *
       3             :  *
       4             :  * Distributed under the OpenDDS License.
       5             :  * See: http://www.opendds.org/license.html
       6             :  */
       7             : 
       8             : #ifndef OPENDDS_DCPS_WRITERDATASAMPLELIST_H
       9             : #define OPENDDS_DCPS_WRITERDATASAMPLELIST_H
      10             : 
      11             : #include "dcps_export.h"
      12             : 
      13             : #include <cstring>
      14             : 
      15             : OPENDDS_BEGIN_VERSIONED_NAMESPACE_DECL
      16             : 
      17             : namespace OpenDDS {
      18             : namespace DCPS {
      19             : 
      20             : class DataSampleElement;
      21             : 
      22             : /**
      23             : * A list of DataSampleElement pointers to be queued by the order the
      24             : * samples are written to the DataWriter (within PRESENTATION.access_scope==TOPIC).
      25             : * Cache the number of elements in the list so that list traversal is
      26             : * not required to find this information.
      27             : * Manages DataSampleElement's previous_writer_sample/next_writer_sample pointers
      28             : */
      29             : class OpenDDS_Dcps_Export WriterDataSampleList {
      30             : public:
      31             : 
      32             :   /// Default constructor clears the list.
      33             :   WriterDataSampleList();
      34           0 :   ~WriterDataSampleList() {}
      35             : 
      36             :   /// Reset to initial state.
      37             :   void reset();
      38             : 
      39             :   ssize_t size() const;
      40             :   DataSampleElement* head() const;
      41             :   DataSampleElement* tail() const;
      42             : 
      43             :   void enqueue_tail(const DataSampleElement* element);
      44             : 
      45             :   bool dequeue_head(DataSampleElement*& stale);
      46             : 
      47             :   bool dequeue(const DataSampleElement* stale);
      48             : 
      49             : protected:
      50             : 
      51             :    /// The first element of the list.
      52             :    DataSampleElement* head_;
      53             : 
      54             :    /// The last element of the list.
      55             :    DataSampleElement* tail_;
      56             : 
      57             :    /// Number of elements in the list.
      58             :    ssize_t size_;
      59             :    //TBD size is never negative so should be size_t but this ripples through
      60             :    // the transport code so leave it for now. SHH
      61             : };
      62             : 
      63             : 
      64             : } // namespace DCPS
      65             : } // namespace OpenDDS
      66             : 
      67             : OPENDDS_END_VERSIONED_NAMESPACE_DECL
      68             : 
      69             : #if defined(__ACE_INLINE__)
      70             : #include "WriterDataSampleList.inl"
      71             : #endif /* __ACE_INLINE__ */
      72             : 
      73             : #endif  /* OPENDDS_DCPS_WRITERDATASAMPLELIST_H */