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 * All rights reserved.
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 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
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/** \file     SEIRemovalApp.h
    \brief    Decoder application class (header)
*/

#ifndef __STREAMMERGEAPP__
#define __STREAMMERGEAPP__

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <stdio.h>
#include <fstream>
#include <iostream>
#include "CommonLib/CommonDef.h"
#include "VLCWriter.h"
#include "CABACWriter.h"
#include "AnnexBread.h"
#include "StreamMergeAppCfg.h"

using namespace std;

// ====================================================================================================================
// Class definition
// ====================================================================================================================

/// decoder application class
class StreamMergeApp : public StreamMergeAppCfg
{

public:
  StreamMergeApp();
  virtual ~StreamMergeApp         ()  {}

  VPS vps;

  uint32_t  mergeStreams            (); ///< main stream merging function
  void      writeNewVPS             (ostream& out, int nNumLayers, int nTemporalId);
};


class SingleLayerStream
{
public:
  /**
  * Create a bytestream reader that will extract bytes from
  * istream.
  *
  * NB, it isn't safe to access istream while in use by a
  * InputByteStream.
  *
  * Side-effects: the exception mask of istream is set to eofbit
  */
  SingleLayerStream()
    : m_numFutureBytes(0)
    , m_futureBytes(0)
  {
  }

  /**
  * Reset the internal state.  Must be called if input stream is
  * modified externally to this class
  */
  void reset()
  {
    m_numFutureBytes = 0;
    m_futureBytes = 0;
  }

  void init(std::istream& istream)
  {
    istream.exceptions(std::istream::eofbit | std::istream::badbit);
  }

  /**
  * returns true if an EOF will be encountered within the next
  * n bytes.
  */
  bool eofBeforeNBytes(uint32_t n, std::istream& m_Input)
  {
    CHECK(n > 4, "Unsupported look-ahead value");
    if (m_numFutureBytes >= n)
    {
      return false;
    }

    n -= m_numFutureBytes;
    try
    {
      for (uint32_t i = 0; i < n; i++)
      {
        m_futureBytes = (m_futureBytes << 8) | m_Input.get();
          m_numFutureBytes++;
      }
    }
    catch (...)
    {
      return true;
    }
    return false;
  }

  /**
  * return the next n bytes in the stream without advancing
  * the stream pointer.
  *
  * Returns: an unsigned integer representing an n byte bigendian
  * word.
  *
  * If an attempt is made to read past EOF, an n-byte word is
  * returned, but the portion that required input bytes beyond EOF
  * is undefined.
  *
  */
  uint32_t peekBytes(uint32_t n, std::istream& m_Input)
  {
    eofBeforeNBytes(n, m_Input);
    return m_futureBytes >> 8 * (m_numFutureBytes - n);
  }

  /**
  * consume and return one byte from the input.
  *
  * If bytestream is already at EOF prior to a call to readByte(),
  * an exception std::ios_base::failure is thrown.
  */
  uint8_t readByte(std::istream& m_Input)
  {
    if (!m_numFutureBytes)
    {
      uint8_t byte = m_Input.get();
      return byte;
    }
    m_numFutureBytes--;
    uint8_t wanted_byte = m_futureBytes >> 8 * m_numFutureBytes;
    m_futureBytes &= ~(0xff << 8 * m_numFutureBytes);
    return wanted_byte;
  }

  /**
  * consume and return n bytes from the input.  n bytes from
  * bytestream are interpreted as bigendian when assembling
  * the return value.
  */
  uint32_t readBytes(uint32_t n, std::istream& m_Input)
  {
    uint32_t val = 0;
    for (uint32_t i = 0; i < n; i++)
    {
      val = (val << 8) | readByte(m_Input);
    }
    return val;
  }

private:
  uint32_t m_numFutureBytes; /* number of valid bytes in m_futureBytes */
  uint32_t m_futureBytes; /* bytes that have been peeked */
};

bool byteStreamNALUnit(SingleLayerStream& bs, std::istream& istream, vector<uint8_t>& nalUnit, AnnexBStats& stats);

#endif // __STREAMMERGEAPP__

