ByteOutputStream.h

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/*
// $Id: //open/dev/fennel/common/ByteOutputStream.h#10 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
// Portions Copyright (C) 1999-2009 John V. Sichi
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef Fennel_ByteOutputStream_Included
#define Fennel_ByteOutputStream_Included

#include "fennel/common/ByteStream.h"
#include "fennel/common/WriteLatency.h"

FENNEL_BEGIN_NAMESPACE

class FENNEL_COMMON_EXPORT ByteOutputStream : virtual public ByteStream
{
    PBuffer pNextByte;

    uint cbWritable;

protected:
    WriteLatency writeLatency;

    explicit ByteOutputStream();

    virtual void flushBuffer(uint cbRequested) = 0;

    virtual void closeImpl();

    void setBuffer(PBuffer pBuffer,uint cbBuffer);

    uint getBytesAvailable() const;

public:
    void writeBytes(void const *pData,uint cbRequested);

    PBuffer getWritePointer(uint cbRequested,uint *pcbActual = NULL);

    void consumeWritePointer(uint cbUsed);

    void hardPageBreak();

    virtual void setWriteLatency(WriteLatency writeLatency);

    template<class T>
    void writeValue(T const &value)
    {
        writeBytes(&value,sizeof(value));
    }
};

inline PBuffer ByteOutputStream::getWritePointer(
    uint cbRequested,uint *pcbActual)
{
    if (cbWritable < cbRequested) {
        flushBuffer(cbRequested);
        assert(cbWritable >= cbRequested);
    }
    if (pcbActual) {
        *pcbActual = cbWritable;
    }
    return pNextByte;
}

inline void ByteOutputStream::consumeWritePointer(uint cbUsed)
{
    assert(cbUsed <= cbWritable);
    cbWritable -= cbUsed;
    pNextByte += cbUsed;
    cbOffset += cbUsed;
}

inline void ByteOutputStream::setBuffer(PBuffer pBuffer,uint cbBuffer)
{
    pNextByte = pBuffer;
    cbWritable = cbBuffer;
}

inline uint ByteOutputStream::getBytesAvailable() const
{
    return cbWritable;
}

FENNEL_END_NAMESPACE

#endif

// End ByteOutputStream.h

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