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/**
 \file     NALread.cpp
 \brief    reading functionality for NAL units
 */


#include <vector>
#include <algorithm>
#include <ostream>

#include "NALread.h"

#include "CommonLib/NAL.h"
#include "CommonLib/BitStream.h"
#include "CommonLib/Rom.h"
#include "CommonLib/dtrace_next.h"

namespace vvdec
{

//! \ingroup DecoderLib
//! \{

#if ENABLE_TRACING
static void xTraceNalUnitHeader(InputNALUnit& nalu)
{
  DTRACE( g_trace_ctx, D_NALUNITHEADER, "*********** NAL UNIT (%s) ***********\n", nalUnitTypeToString(nalu.m_nalUnitType) );
  bool zeroTidRequiredFlag = 0;
  if((nalu.m_nalUnitType >= 16) && (nalu.m_nalUnitType <= 31)) {
    zeroTidRequiredFlag = 1;
  }
  DTRACE( g_trace_ctx, D_NALUNITHEADER, "%-50s u(%d)  : %u\n", "zero_tid_required_flag", 1, zeroTidRequiredFlag );
  DTRACE( g_trace_ctx, D_NALUNITHEADER, "%-50s u(%d)  : %u\n", "nuh_temporal_id_plus1", 3, nalu.m_temporalId + 1 );
  DTRACE( g_trace_ctx, D_NALUNITHEADER, "%-50s u(%d)  : %u\n", "nal_unit_type_lsb", 4, (nalu.m_nalUnitType) - (zeroTidRequiredFlag << 4));
  DTRACE( g_trace_ctx, D_NALUNITHEADER, "%-50s u(%d)  : %u\n", "nuh_layer_id_plus1", 7, nalu.m_nuhLayerId+1);
  DTRACE( g_trace_ctx, D_NALUNITHEADER, "%-50s u(%d)  : %u\n", "nuh_reserved_zero_bit", 1, 0 );
}
#endif

void InputNALUnit::readNalUnitHeader()
{
  InputNALUnit&   nalu = *this;
  InputBitstream& bs   = nalu.getBitstream();

  nalu.m_forbiddenZeroBit   = bs.read(1);                 // forbidden zero bit
  nalu.m_nuhReservedZeroBit = bs.read(1);                 // nuh_reserved_zero_bit
  nalu.m_nuhLayerId         = bs.read(6);                 // nuh_layer_id
  CHECK( nalu.m_nuhLayerId < 0, "this needs to be adjusted for the reco yuv output" );
  CHECK( nalu.m_nuhLayerId > 55, "The value of nuh_layer_id shall be in the range of 0 to 55, inclusive" );
  nalu.m_nalUnitType        = (NalUnitType) bs.read(5);   // nal_unit_type
  nalu.m_temporalId         = bs.read(3) - 1;             // nuh_temporal_id_plus1

#if ENABLE_TRACING
  xTraceNalUnitHeader(nalu);
#endif

  // only check these rules for base layer
  if (nalu.m_nuhLayerId == 0)
  {
    if ( nalu.m_temporalId )
    {
    }
    else
    {
      CHECK( nalu.m_nalUnitType == NAL_UNIT_CODED_SLICE_STSA, "When NAL unit type is equal to STSA_NUT, TemporalId shall not be equal to 0" );
    }
  }
}
}
