GmRingBuffer.hpp

/*
 * GmRingBuffer.hpp
 *
 *  Created on: Jul 23, 2016
 *      Author: rcram
 */
 
#ifndef GMRINGBUFFER_HPP_
#define GMRINGBUFFER_HPP_
 
namespace Geometrics
{
 
   #define GM_RING_BUFFER_OK                    0
   #define GM_RING_BUFFER_WRONG_RECORD_SIZE     1
   #define GM_RING_BUFFER_INVALID_INDEX         2
   #define GM_RING_BUFFER_NO_RECORDS            3
   #define GM_RING_BUFFER_FAILURE               4
   #define GM_RING_BUFFER_OVERRUN_OVERWROTE     5
   #define GM_RING_BUFFER_OVERRUN_NO_WRITE      6
   #define GM_RING_BUFFER_EMPTY                 7
   #define GM_RING_BUFFER_NO_UNNOTICED          8
   #define GM_RING_BUFFER_NULL_DESTINATION      9
 
 
   // Initially, this is FIFO only.
   // This class has no concurrency control.  That must occur
   //   in the clients of this class.
   // Would be nice to add priority, so that for purposes
   //    such as task switching,
   //    we could put higher-priority items in the buffer.
   class CRingBuffer
   {
   public:
      CRingBuffer         (int     iMaxItems,
                           int     iItemSize,
                           Bool    bOkToOverrun,
                           Bool    bNotices);
      CRingBuffer         (int     iMaxItems,
                           int     iItemSize,
                           Bool    bOkToOverrun,
                           Bool    bNotices,
                           UInt8  *puiBuffer,
                           UInt32  uiBufferSize);
      ~CRingBuffer        ();
 
     int  ReadRecord        (UInt8  *pcDestination,
                 int     iSize);
     int  NoticeRecord      (int    *piDestination);
     int  WriteRecord       (UInt8  *pcSource,
                                int     iSize);
     int  ForgetNextRecord  ();
     int  CheckToWrite      (int iSize);
     void SetEmpty          ();
     Bool IsEmpty           ();
     Bool HasData           ();
     Bool HasUnnoticedData  ();
     int  ReserveRecord     (int iSize, int *pIndex);
     UInt8  *GetBuffer          (int     iBufferIndex);
     int  CopyAndCommitData        (UInt8      *pcSource,
                 int         index,
                 int         iSize);
     int  CommitData (int index);
     int  Size();
     int  MaxSize();
 
   protected:
     int  InternalWriteRecord  (UInt8   *pcSource,
                int      iSize);
     
     //     UInt8  *GetBuffer          (int     iBufferIndex);
     
     int                m_iMaxItems,
                        m_iItemSize,
                        m_iLastBufferRead,
                        m_iLastBufferNoticed,
                        m_iLastBufferWritten;
     
     // To manage overruns.  See notes in CPP
     Bool               m_bNextWriteWouldOverrun,
       m_bNextWriteWouldOverrunNotice,
       m_bOkToOverrun,
       m_bNotices;
     
     UInt8             *m_Buffer;
   };
}
#endif /* GMRINGBUFFER_HPP_ */