ByteOutputStream.h

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00001 /*
00002 // $Id: //open/dev/fennel/common/ByteOutputStream.h#10 $
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_ByteOutputStream_Included
00025 #define Fennel_ByteOutputStream_Included
00026 
00027 #include "fennel/common/ByteStream.h"
00028 #include "fennel/common/WriteLatency.h"
00029 
00030 FENNEL_BEGIN_NAMESPACE
00031 
00035 class FENNEL_COMMON_EXPORT ByteOutputStream : virtual public ByteStream
00036 {
00040     PBuffer pNextByte;
00041 
00045     uint cbWritable;
00046 
00047 protected:
00051     WriteLatency writeLatency;
00052 
00053     explicit ByteOutputStream();
00054 
00061     virtual void flushBuffer(uint cbRequested) = 0;
00062 
00063     virtual void closeImpl();
00064 
00072     void setBuffer(PBuffer pBuffer,uint cbBuffer);
00073 
00077     uint getBytesAvailable() const;
00078 
00079 public:
00087     void writeBytes(void const *pData,uint cbRequested);
00088 
00104     PBuffer getWritePointer(uint cbRequested,uint *pcbActual = NULL);
00105 
00112     void consumeWritePointer(uint cbUsed);
00113 
00119     void hardPageBreak();
00120 
00127     virtual void setWriteLatency(WriteLatency writeLatency);
00128 
00134     template<class T>
00135     void writeValue(T const &value)
00136     {
00137         writeBytes(&value,sizeof(value));
00138     }
00139 };
00140 
00141 inline PBuffer ByteOutputStream::getWritePointer(
00142     uint cbRequested,uint *pcbActual)
00143 {
00144     if (cbWritable < cbRequested) {
00145         flushBuffer(cbRequested);
00146         assert(cbWritable >= cbRequested);
00147     }
00148     if (pcbActual) {
00149         *pcbActual = cbWritable;
00150     }
00151     return pNextByte;
00152 }
00153 
00154 inline void ByteOutputStream::consumeWritePointer(uint cbUsed)
00155 {
00156     assert(cbUsed <= cbWritable);
00157     cbWritable -= cbUsed;
00158     pNextByte += cbUsed;
00159     cbOffset += cbUsed;
00160 }
00161 
00162 inline void ByteOutputStream::setBuffer(PBuffer pBuffer,uint cbBuffer)
00163 {
00164     pNextByte = pBuffer;
00165     cbWritable = cbBuffer;
00166 }
00167 
00168 inline uint ByteOutputStream::getBytesAvailable() const
00169 {
00170     return cbWritable;
00171 }
00172 
00173 FENNEL_END_NAMESPACE
00174 
00175 #endif
00176 
00177 // End ByteOutputStream.h

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