SegStream.h

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00001 /*
00002 // $Id: //open/dev/fennel/segment/SegStream.h#12 $
00003 // Fennel is a library of data storage and processing components.
00004 // Copyright (C) 2005-2009 The Eigenbase Project
00005 // Copyright (C) 2005-2009 SQLstream, Inc.
00006 // Copyright (C) 2005-2009 LucidEra, Inc.
00007 // Portions Copyright (C) 1999-2009 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_SegStream_Included
00025 #define Fennel_SegStream_Included
00026 
00027 #include "fennel/common/ByteStream.h"
00028 #include "fennel/segment/SegPageLock.h"
00029 #include "fennel/common/PseudoUuid.h"
00030 
00031 FENNEL_BEGIN_NAMESPACE
00032 
00033 // NOTE:  read comments on struct StoredNode before modifying
00034 // SegStreamNode
00035 
00039 struct FENNEL_SEGMENT_EXPORT SegStreamNode
00040     : public StoredNode
00041 {
00042     static const MagicNumber MAGIC_NUMBER = 0x99f28198d53750a5LL;
00043 
00044     uint cbData;
00045 };
00046 
00051 struct FENNEL_SEGMENT_EXPORT SegStreamCrc
00052 {
00056     PageId pageId;
00057 
00061     PseudoUuid onlineUuid;
00062 
00066     uint64_t checksum;
00067 };
00068 
00069 typedef SegNodeLock<SegStreamNode> SegStreamLock;
00070 
00074 struct FENNEL_SEGMENT_EXPORT SegStreamPosition
00075 {
00079     SegByteId segByteId;
00080 
00084     FileSize cbOffset;
00085 };
00086 
00090 class FENNEL_SEGMENT_EXPORT SegStream
00091     : virtual public ByteStream
00092 {
00093 protected:
00097     SegmentAccessor segmentAccessor;
00098 
00102     SegStreamLock pageLock;
00103 
00107     uint cbPageHeader;
00108 
00109     // implement the ClosableObject interface
00110     virtual void closeImpl();
00111 
00112     explicit SegStream(SegmentAccessor const &,uint cbExtraHeader);
00113 public:
00114 
00120     virtual void getSegPos(SegStreamPosition &pos) = 0;
00121 
00125     SharedSegment getSegment() const;
00126 
00130     SegmentAccessor const &getSegmentAccessor() const;
00131 };
00132 
00137 class FENNEL_SEGMENT_EXPORT SegStreamMarker
00138     : public ByteStreamMarker
00139 {
00140     friend class SegInputStream;
00141 
00145     SegStreamPosition segPos;
00146 
00147     explicit SegStreamMarker(SegStream const &segStream);
00148 
00149     // implement ByteStreamMarker
00150     virtual FileSize getOffset() const;
00151 };
00152 
00153 FENNEL_END_NAMESPACE
00154 
00155 #endif
00156 
00157 // End SegStream.h

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