//
// Copyright (c) Microsoft Corporation.  All rights reserved.
//
//
// Use of this source code is subject to the terms of the Microsoft shared
// source or premium shared source license agreement under which you licensed
// this source code. If you did not accept the terms of the license agreement,
// you are not authorized to use this source code. For the terms of the license,
// please see the license agreement between you and Microsoft or, if applicable,
// see the SOURCE.RTF on your install media or the root of your tools installation.
// THE SOURCE CODE IS PROVIDED "AS IS", WITH NO WARRANTIES.
//

#ifndef __BTAGUTIL_H__
#define __BTAGUTIL_H__

#include <windows.h>

#define DEFAULT_BUFFER_SIZE     64
#define MAX_BUFFER_SIZE         4096       

class CBuffer {
public:
    CBuffer(void)
    {
        m_pBuffer = m_Buffer;
        m_iSize = DEFAULT_BUFFER_SIZE;
    }
    
    ~CBuffer(void)
    {
        if (m_pBuffer != m_Buffer) {
            delete[] m_pBuffer;
        }
    }
    
    PBYTE GetBuffer(int iSize, BOOL fPreserveData = FALSE)
    {
        //
        // If buffer is not big enough, we have to allocate new buffer
        // which is big enough.
        //

        if (iSize > MAX_BUFFER_SIZE) {
            return NULL;
        }
        else if (iSize > m_iSize) {
            PBYTE pTmp = new BYTE[iSize];
            if (! pTmp) {
                return NULL;
            }

            if (fPreserveData) {
                memcpy(pTmp, m_pBuffer, m_iSize);
            }
        
            // Delete current buffer if it was allocated on the heap
            if (m_pBuffer != m_Buffer) {
                delete[] m_pBuffer;
            }

            // If alloc succeeded then update buffer and size
            m_pBuffer = pTmp;
            m_iSize = iSize;
        }

        return m_pBuffer;
    }
    
    int GetSize(void)
    {
        return m_iSize;
    }
    
private:
    CBuffer(const CBuffer&){} // don't want to copy this object
    BYTE m_Buffer[DEFAULT_BUFFER_SIZE];
    PBYTE m_pBuffer;
    int m_iSize;
};


#endif // __BTAGUTIL_H__

