/* -----------------------------------------------------------------------------
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the Software are granted under this license.

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Copyright (c) 2018-2023, Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. & The VVdeC Authors.
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     * 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
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     * Neither the name of the copyright holder nor the names of its
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     software without specific prior written permission.

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THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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------------------------------------------------------------------------------------------- */

#pragma once

#include <sstream>
#include <list>
#include "CommonDef.h"

namespace vvdec
{

class OutputBitstream;

/**
 * Represents a single NALunit header and the associated RBSPayload
 */
struct NALUnit
{
  NalUnitType m_nalUnitType = NAL_UNIT_INVALID;   ///< nal_unit_type
  uint32_t    m_temporalId  = 0;                  ///< temporal_id
  uint32_t    m_nuhLayerId  = 0;                  ///< nuh_layer_id
  uint32_t    m_forbiddenZeroBit   = 0;
  uint32_t    m_nuhReservedZeroBit = 0;

  uint64_t    m_bits     = 0;            ///< original nal unit bits
  uint64_t    m_cts      = 0;            ///< composition time stamp in TicksPerSecond
  uint64_t    m_dts      = 0;            ///< decoding time stamp in TicksPerSecond
  bool        m_rap      = false;        ///< random access point flag

  NALUnit(const NALUnit &src)
    : m_nalUnitType (src.m_nalUnitType)
    , m_temporalId  (src.m_temporalId)
    , m_nuhLayerId  (src.m_nuhLayerId)
    , m_forbiddenZeroBit  (src.m_forbiddenZeroBit)
    , m_nuhReservedZeroBit(src.m_nuhReservedZeroBit)
  {}

  /** construct an NALunit structure with given header values. */
  NALUnit( NalUnitType nalUnitType,
           int         temporalId = 0 ,
           int         nuhLayerId = 0 )
    : m_nalUnitType (nalUnitType)
    , m_temporalId  (temporalId)
    , m_nuhLayerId  (nuhLayerId)
  {}

  /** default constructor - no initialization; must be performed by user */
  NALUnit() {}

  virtual ~NALUnit() { }

  /** returns true if the NALunit is a slice NALunit */
  bool isSlice()
  {
    return m_nalUnitType == NAL_UNIT_CODED_SLICE_TRAIL
        || m_nalUnitType == NAL_UNIT_CODED_SLICE_STSA
        || m_nalUnitType == NAL_UNIT_CODED_SLICE_RADL
        || m_nalUnitType == NAL_UNIT_CODED_SLICE_RASL
        || m_nalUnitType == NAL_UNIT_CODED_SLICE_IDR_W_RADL
        || m_nalUnitType == NAL_UNIT_CODED_SLICE_IDR_N_LP
        || m_nalUnitType == NAL_UNIT_CODED_SLICE_CRA
        || m_nalUnitType == NAL_UNIT_CODED_SLICE_GDR
        ;
  }
  bool isSei()
  {
    return m_nalUnitType == NAL_UNIT_PREFIX_SEI
        || m_nalUnitType == NAL_UNIT_SUFFIX_SEI;
  }

  bool isVcl()
  {
    return isVclNalUnitType(m_nalUnitType);
  }

  static bool isVclNalUnitType(NalUnitType t)
  {
    return t <= NAL_UNIT_RESERVED_IRAP_VCL_11;
  }
};

struct OutputNALUnit;

/**
 * A single NALunit, with complete payload in EBSP format.
 */
struct NALUnitEBSP : public NALUnit
{
  std::ostringstream m_nalUnitData;

  /**
   * convert the OutputNALUnit nalu into EBSP format by writing out
   * the NALUnit header, then the rbsp_bytes including any
   * emulation_prevention_three_byte symbols.
   */
  NALUnitEBSP(OutputNALUnit& nalu);
};
//! \}
//! \}


/**
 * An AccessUnit is a list of one or more NAL units, according to the
 * working draft.  All NAL units within the object belong to the same
 * access unit.
 *
 * NALUnits held in the AccessUnit list are in EBSP format.  Attempting
 * to insert an OutputNALUnit into the access unit will automatically cause
 * the nalunit to have its headers written and anti-emulation performed.
 *
 * The AccessUnit owns all pointers stored within.  Destroying the
 * AccessUnit will delete all contained objects.
 */
class AccessUnit : public std::list<NALUnitEBSP*> // NOTE: Should not inherit from STL.
{
public:
  ~AccessUnit()
  {
    for (AccessUnit::iterator it = this->begin(); it != this->end(); it++)
    {
      delete *it;
    }
  }
};

}