ExternalSortRunAccessor.h

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00001 /*
00002 // $Id: //open/dev/fennel/sorter/ExternalSortRunAccessor.h#2 $
00003 // Fennel is a library of data storage and processing components.
00004 // Copyright (C) 2005-2009 The Eigenbase Project
00005 // Copyright (C) 2009-2009 SQLstream, Inc.
00006 // Copyright (C) 2004-2009 LucidEra, Inc.
00007 // Portions Copyright (C) 2004-2009 John V. Sichi
00008 //
00009 // This program is free software; you can redistribute it and/or modify it
00010 // under the terms of the GNU General Public License as published by the Free
00011 // Software Foundation; either version 2 of the License, or (at your option)
00012 // any later version approved by The Eigenbase Project.
00013 //
00014 // This program is distributed in the hope that it will be useful,
00015 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00016 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00017 // GNU General Public License for more details.
00018 //
00019 // You should have received a copy of the GNU General Public License
00020 // along with this program; if not, write to the Free Software
00021 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00022 */
00023 
00024 #ifndef Fennel_ExternalSortRunAccessor_Included
00025 #define Fennel_ExternalSortRunAccessor_Included
00026 
00027 #include "fennel/tuple/TupleAccessor.h"
00028 #include "fennel/sorter/ExternalSortSubStream.h"
00029 
00030 FENNEL_BEGIN_NAMESPACE
00031 
00032 class ExternalSortInfo;
00033 
00037 class FENNEL_SORTER_EXPORT ExternalSortRunAccessor
00038     : public ExternalSortSubStream
00039 {
00043     ExternalSortInfo &sortInfo;
00044 
00045     // TODO:  comment or replace
00046     TupleAccessor tupleAccessor;
00047 
00052     ExternalSortFetchArray fetchArray;
00053 
00058     PBuffer ppTupleBuffers[EXTSORT_FETCH_ARRAY_SIZE];
00059 
00063     SharedSegInputStream pSegInputStream;
00064 
00068     SharedSegOutputStream pSegOutputStream;
00069 
00073     SharedSegStreamAllocation pStoredRun;
00074 
00075 // ----------------------------------------------------------------------
00076 // private methods
00077 // ----------------------------------------------------------------------
00078 
00079     void clearFetch()
00080     {
00081         fetchArray.nTuples = 0;
00082         fetchArray.ppTupleBuffers = ppTupleBuffers;
00083         memset(ppTupleBuffers,0,sizeof(ppTupleBuffers));
00084     }
00085 
00086 public:
00087     explicit ExternalSortRunAccessor(ExternalSortInfo &);
00088     virtual ~ExternalSortRunAccessor();
00089 
00094     void initRead();
00095 
00101     void startRead(
00102         SharedSegStreamAllocation pStoredRunInit);
00103 
00107     void resetRead();
00108 
00115     void storeRun(ExternalSortSubStream &subStream);
00116 
00120     SharedSegStreamAllocation getStoredRun();
00121 
00125     void releaseResources();
00126 
00127     // implement ExternalSortSubStream
00128     virtual ExternalSortFetchArray &bindFetchArray();
00129     virtual ExternalSortRC fetch(uint nTuplesRequested);
00130 };
00131 
00132 FENNEL_END_NAMESPACE
00133 
00134 #endif
00135 
00136 // End ExternalSortRunAccessor.h

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