/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 * 

 *      http://www.apache.org/licenses/LICENSE-2.0

 * 

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#if !defined(XMLBUFFERMGR_HPP)

#define XMLBUFFERMGR_HPP

#include <xercesc/framework/XMLBuffer.hpp>

XERCES_CPP_NAMESPACE_BEGIN

class XMLBufBid;

/**

 *  There are many places where XMLBuffer objects are needed. In order to

 *  avoid either constantly creating and destroying them or maintaining a

 *  fixed set and worrying about accidental reuse, a buffer manager can

 *  provide a pool of buffers which can be temporarily used and then put

 *  back into the pool. This provides a good compromise between performance

 *  and easier maintenance.

 */

class XMLPARSER_EXPORT XMLBufferMgr : public XMemory

{

public :

    // -----------------------------------------------------------------------

    //  Constructors and Destructor

    // -----------------------------------------------------------------------

    /** @name Constructor */

    //@{

    XMLBufferMgr(MemoryManager* const manager = XMLPlatformUtils::fgMemoryManager);

    //@}

    /** @name Destructor */

    //@{

    ~XMLBufferMgr();

    //@}

    // -----------------------------------------------------------------------

    //  Buffer management

    // -----------------------------------------------------------------------

    XMLBuffer& bidOnBuffer();

    void releaseBuffer(XMLBuffer& toRelease);

	// -----------------------------------------------------------------------

    //  Getter methods

    // -----------------------------------------------------------------------

    unsigned int getBufferCount() const;

    unsigned int getAvailableBufferCount() const;

private :

    // -----------------------------------------------------------------------

    //  Unimplemented constructors and operators

    // -----------------------------------------------------------------------

    XMLBufferMgr(const XMLBufferMgr&);

    XMLBufferMgr& operator=(const XMLBufferMgr&);

    // -----------------------------------------------------------------------

    //  Private data members

    //

    //  fBufCount

    //      The count of buffers that have been allocated so far.

    //

    //  fBufList;

    //      The list of pointers to buffers that are loaned out. There will

    //      never be a lot of them, so a flat list is good enough.

    // -----------------------------------------------------------------------

    unsigned int    fBufCount;

    MemoryManager*  fMemoryManager;

    XMLBuffer**     fBufList;

};

inline unsigned int XMLBufferMgr::getBufferCount() const

{

    return fBufCount;

}

inline unsigned int XMLBufferMgr::getAvailableBufferCount() const

{

    unsigned available = fBufCount;

    for (unsigned int index = 0; index < fBufCount && fBufList[index]; index++)

    {

        if (fBufList[index]->getInUse())

            --available;

    }

    return available;

}

/**

 *  XMLBufBid is a scoped based janitor that allows the scanner code to ask

 *  for a buffer on a scoped basis and then insure that it gets freed back

 *  into the pool no matter how the scope is exited (exception or normal exit.)

 */

class XMLBufBid : public XMemory

{

public :

    // -----------------------------------------------------------------------

    //  Constructors and Destructor

    // -----------------------------------------------------------------------

    XMLBufBid(XMLBufferMgr* const srcMgr) :

        fBuffer(srcMgr->bidOnBuffer())

        , fMgr(srcMgr)

    {

    }

    ~XMLBufBid()

    {

        fMgr->releaseBuffer(fBuffer);

    }

    // -----------------------------------------------------------------------

    //  Buffer access

    // -----------------------------------------------------------------------

    void append(const XMLCh toAppend)

    {

        fBuffer.append(toAppend);

    }

    void append(const XMLCh* const toAppend, const unsigned int count = 0)

    {

        fBuffer.append(toAppend, count);

    }

    const XMLBuffer& getBuffer() const

    {

        return fBuffer;

    }

    XMLBuffer& getBuffer()

    {

        return fBuffer;

    }

    const XMLCh* getRawBuffer() const

    {

        fBuffer.fBuffer[fBuffer.fIndex] = 0;

        return fBuffer.fBuffer;

    }

    XMLCh* getRawBuffer()

    {

        fBuffer.fBuffer[fBuffer.fIndex] = 0;

        return fBuffer.fBuffer;

    }

    unsigned int getLen() const

    {

        return fBuffer.fIndex;

    }

    bool isEmpty() const

    {

        return (fBuffer.fIndex == 0);

    }

    void reset()

    {

        fBuffer.reset();

    }

    void set(const XMLCh* const chars, const unsigned int count = 0)

    {

        fBuffer.set(chars, count);

    }

private :

    // -----------------------------------------------------------------------

    //  Unimplemented constructors and operators

    // -----------------------------------------------------------------------

    XMLBufBid(const XMLBufBid&);

    XMLBufBid& operator=(const XMLBufBid&);

    // -----------------------------------------------------------------------

    //  Private data members

    //

    //  fBuffer

    //      This is the buffer we got, and which we will release.

    //

    //  fMgr

    //      This is the buffer manager we got the buffer from. This is needed

    //      to release the buffer later.

    // -----------------------------------------------------------------------

    XMLBuffer&          fBuffer;

    XMLBufferMgr* const fMgr;

};

XERCES_CPP_NAMESPACE_END

#endif