Program: CWE-119
Project: CVE-2015-8792
Buggy source:
/****************************************************************************
** libmatroska : parse Matroska files, see http://www.matroska.org/
**
** <file/class description>
**
** Copyright (C) 2002-2010 Steve Lhomme.  All rights reserved.
**
** This library is free software; you can redistribute it and/or
** modify it under the terms of the GNU Lesser General Public
** License as published by the Free Software Foundation; either
** version 2.1 of the License, or (at your option) any later version.
**
** This library is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** Lesser General Public License for more details.
**
** You should have received a copy of the GNU Lesser General Public
** License along with this library; if not, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
**
** See http://www.gnu.org/licenses/lgpl-2.1.html for LGPL licensing information.**
** Contact license@matroska.org if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/

/*!
  \file
  \version \$Id: KaxBlock.cpp 1265 2007-01-14 17:20:35Z mosu $
  \author Steve Lhomme     <robux4 @ users.sf.net>
  \author Julien Coloos    <suiryc @ users.sf.net>
  \author Moritz Bunkus <moritz@bunkus.org>
*/
#include <cassert>

//#include <streams.h>

#include "ebml/MemReadIOCallback.h"
#include "ebml/SafeReadIOCallback.h"
#include "matroska/KaxBlock.h"
#include "matroska/KaxContexts.h"
#include "matroska/KaxBlockData.h"
#include "matroska/KaxCluster.h"
#include "matroska/KaxDefines.h"

START_LIBMATROSKA_NAMESPACE

DataBuffer * DataBuffer::Clone()
{
  binary *ClonedData = (binary *)malloc(mySize * sizeof(binary));
  assert(ClonedData != NULL);
  memcpy(ClonedData, myBuffer ,mySize );

  SimpleDataBuffer * result = new SimpleDataBuffer(ClonedData, mySize, 0);
  result->bValidValue = bValidValue;
  return result;
}

SimpleDataBuffer::SimpleDataBuffer(const SimpleDataBuffer & ToClone)
  :DataBuffer((binary *)malloc(ToClone.mySize * sizeof(binary)), ToClone.mySize, myFreeBuffer)
{
  assert(myBuffer != NULL);
  memcpy(myBuffer, ToClone.myBuffer ,mySize );
  bValidValue = ToClone.bValidValue;
}

bool KaxInternalBlock::ValidateSize() const
{
  return (GetSize() >= 4); /// for the moment
}

KaxInternalBlock::~KaxInternalBlock()
{
  ReleaseFrames();
}

KaxInternalBlock::KaxInternalBlock(const KaxInternalBlock & ElementToClone)
  :EbmlBinary(ElementToClone)
  ,myBuffers(ElementToClone.myBuffers.size())
  ,Timecode(ElementToClone.Timecode)
  ,LocalTimecode(ElementToClone.LocalTimecode)
  ,bLocalTimecodeUsed(ElementToClone.bLocalTimecodeUsed)
  ,TrackNumber(ElementToClone.TrackNumber)
  ,ParentCluster(ElementToClone.ParentCluster) ///< \todo not exactly
{
  // add a clone of the list
  std::vector<DataBuffer *>::const_iterator Itr = ElementToClone.myBuffers.begin();
  std::vector<DataBuffer *>::iterator myItr = myBuffers.begin();
  while (Itr != ElementToClone.myBuffers.end()) {
    *myItr = (*Itr)->Clone();
    ++Itr; ++myItr;
  }
}


KaxBlockGroup::~KaxBlockGroup()
{
  //NOTE("KaxBlockGroup::~KaxBlockGroup");
}

KaxBlockGroup::KaxBlockGroup(EBML_EXTRA_DEF)
  :EbmlMaster(EBML_CLASS_SEMCONTEXT(KaxBlockGroup) EBML_DEF_SEP EBML_EXTRA_CALL)
  ,ParentCluster(NULL)
  ,ParentTrack(NULL)
{}

/*!
  \todo handle flags
  \todo hardcoded limit of the number of frames in a lace should be a parameter
  \return true if more frames can be added to this Block
*/
bool KaxInternalBlock::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, LacingType lacing, bool invisible)
{
  SetValueIsSet();
  if (myBuffers.size() == 0) {
    // first frame
    Timecode = timecode;
    TrackNumber = track.TrackNumber();
    mInvisible = invisible;
    mLacing = lacing;
  }
  myBuffers.push_back(&buffer);

  // we don't allow more than 8 frames in a Block because the overhead improvement is minimal
  if (myBuffers.size() >= 8 || lacing == LACING_NONE)
    return false;

  if (lacing == LACING_XIPH)
    // decide wether a new frame can be added or not
    // a frame in a lace is not efficient when the place necessary to code it in a lace is bigger
    // than the size of a simple Block. That means more than 6 bytes (4 in struct + 2 for EBML) to code the size
    return (buffer.Size() < 6*0xFF);
  else
    return true;
}

/*!
  \return Returns the lacing type that produces the smallest footprint.
*/
LacingType KaxInternalBlock::GetBestLacingType() const {
  int XiphLacingSize, EbmlLacingSize, i;
  bool SameSize = true;

  if (myBuffers.size() <= 1)
    return LACING_NONE;

  XiphLacingSize = 1; // Number of laces is stored in 1 byte.
  EbmlLacingSize = 1;
  for (i = 0; i < (int)myBuffers.size() - 1; i++) {
    if (myBuffers[i]->Size() != myBuffers[i + 1]->Size())
      SameSize = false;
    XiphLacingSize += myBuffers[i]->Size() / 255 + 1;
  }
  EbmlLacingSize += CodedSizeLength(myBuffers[0]->Size(), 0, IsFiniteSize());
  for (i = 1; i < (int)myBuffers.size() - 1; i++)
    EbmlLacingSize += CodedSizeLengthSigned(int64(myBuffers[i]->Size()) - int64(myBuffers[i - 1]->Size()), 0);
  if (SameSize)
    return LACING_FIXED;
  else if (XiphLacingSize < EbmlLacingSize)
    return LACING_XIPH;
  else
    return LACING_EBML;
}

filepos_t KaxInternalBlock::UpdateSize(bool /* bSaveDefault */, bool /* bForceRender */)
{
  LacingType LacingHere;
  assert(EbmlBinary::GetBuffer() == NULL); // Data is not used for KaxInternalBlock
  assert(TrackNumber < 0x4000); // no more allowed for the moment
  unsigned int i;

  // compute the final size of the data
  switch (myBuffers.size()) {
    case 0:
      SetSize_(0);
      break;
    case 1:
      SetSize_(4 + myBuffers[0]->Size());
      break;
    default:
      SetSize_(4 + 1); // 1 for the lacing head
      if (mLacing == LACING_AUTO)
        LacingHere = GetBestLacingType();
      else
        LacingHere = mLacing;
      switch (LacingHere) {
        case LACING_XIPH:
          for (i=0; i<myBuffers.size()-1; i++) {
            SetSize_(GetSize() + myBuffers[i]->Size() + (myBuffers[i]->Size() / 0xFF + 1));
          }
          break;
        case LACING_EBML:
          SetSize_(GetSize() + myBuffers[0]->Size() + CodedSizeLength(myBuffers[0]->Size(), 0, IsFiniteSize()));
          for (i=1; i<myBuffers.size()-1; i++) {
            SetSize_(GetSize() + myBuffers[i]->Size() + CodedSizeLengthSigned(int64(myBuffers[i]->Size()) - int64(myBuffers[i-1]->Size()), 0));
          }
          break;
        case LACING_FIXED:
          for (i=0; i<myBuffers.size()-1; i++) {
            SetSize_(GetSize() + myBuffers[i]->Size());
          }
          break;
        default:
          i = 0;
          assert(0);
      }
      // Size of the last frame (not in lace)
      SetSize_(GetSize() + myBuffers[i]->Size());
      break;
  }

  if (TrackNumber >= 0x80)
    SetSize_(GetSize() + 1); // the size will be coded with one more octet

  return GetSize();
}

#if MATROSKA_VERSION >= 2
KaxBlockVirtual::KaxBlockVirtual(const KaxBlockVirtual & ElementToClone)
  :EbmlBinary(ElementToClone)
  ,Timecode(ElementToClone.Timecode)
  ,TrackNumber(ElementToClone.TrackNumber)
  ,ParentCluster(ElementToClone.ParentCluster) ///< \todo not exactly
{
  SetBuffer(DataBlock,sizeof(DataBlock));
  SetValueIsSet(false);
}

KaxBlockVirtual::KaxBlockVirtual(EBML_EXTRA_DEF)
  :EBML_DEF_BINARY(KaxBlockVirtual)EBML_DEF_SEP ParentCluster(NULL)
{
  SetBuffer(DataBlock,sizeof(DataBlock));
  SetValueIsSet(false);
}

KaxBlockVirtual::~KaxBlockVirtual()
{
  if(GetBuffer() == DataBlock)
    SetBuffer( NULL, 0 );
}

filepos_t KaxBlockVirtual::UpdateSize(bool /* bSaveDefault */, bool /* bForceRender */)
{
  assert(TrackNumber < 0x4000);
  binary *cursor = EbmlBinary::GetBuffer();
  // fill data
  if (TrackNumber < 0x80) {
    assert(GetSize() >= 4);
    *cursor++ = TrackNumber | 0x80; // set the first bit to 1
  } else {
    assert(GetSize() >= 5);
    *cursor++ = (TrackNumber >> 8) | 0x40; // set the second bit to 1
    *cursor++ = TrackNumber & 0xFF;
  }

  assert(ParentCluster != NULL);
  int16 ActualTimecode = ParentCluster->GetBlockLocalTimecode(Timecode);
  big_int16 b16(ActualTimecode);
  b16.Fill(cursor);
  cursor += 2;

  *cursor++ = 0; // flags

  return GetSize();
}
#endif // MATROSKA_VERSION

/*!
  \todo more optimisation is possible (render the Block head and don't copy the buffer in memory, care should be taken with the allocation of Data)
  \todo the actual timecode to write should be retrieved from the Cluster from here
*/
filepos_t KaxInternalBlock::RenderData(IOCallback & output, bool /* bForceRender */, bool /* bSaveDefault */)
{
  if (myBuffers.size() == 0) {
    return 0;
  } else {
    assert(TrackNumber < 0x4000);
    binary BlockHead[5], *cursor = BlockHead;
    unsigned int i;

    if (myBuffers.size() == 1) {
      SetSize_(4);
      mLacing = LACING_NONE;
    } else {
      if (mLacing == LACING_NONE)
        mLacing = LACING_EBML; // supposedly the best of all
      SetSize_(4 + 1); // 1 for the lacing head (number of laced elements)
    }
    if (TrackNumber > 0x80)
      SetSize_(GetSize() + 1);

    // write Block Head
    if (TrackNumber < 0x80) {
      *cursor++ = TrackNumber | 0x80; // set the first bit to 1
    } else {
      *cursor++ = (TrackNumber >> 8) | 0x40; // set the second bit to 1
      *cursor++ = TrackNumber & 0xFF;
    }

    assert(ParentCluster != NULL);
    int16 ActualTimecode = ParentCluster->GetBlockLocalTimecode(Timecode);
    big_int16 b16(ActualTimecode);
    b16.Fill(cursor);
    cursor += 2;

    *cursor = 0; // flags

    if (mLacing == LACING_AUTO) {
      mLacing = GetBestLacingType();
    }

    // invisible flag
    if (mInvisible)
      *cursor = 0x08;

    if (bIsSimple) {
      if (bIsKeyframe)
        *cursor |= 0x80;
      if (bIsDiscardable)
        *cursor |= 0x01;
    }

    // lacing flag
    switch (mLacing) {
      case LACING_XIPH:
        *cursor++ |= 0x02;
        break;
      case LACING_EBML:
        *cursor++ |= 0x06;
        break;
      case LACING_FIXED:
        *cursor++ |= 0x04;
        break;
      case LACING_NONE:
        break;
      default:
        assert(0);
    }

    output.writeFully(BlockHead, 4 + ((TrackNumber > 0x80) ? 1 : 0));

    binary tmpValue;
    switch (mLacing) {
      case LACING_XIPH:
        // number of laces
        tmpValue = myBuffers.size()-1;
        output.writeFully(&tmpValue, 1);

        // set the size of each member in the lace
        for (i=0; i<myBuffers.size()-1; i++) {
          tmpValue = 0xFF;
          uint16 tmpSize = myBuffers[i]->Size();
          while (tmpSize >= 0xFF) {
            output.writeFully(&tmpValue, 1);
            SetSize_(GetSize() + 1);
            tmpSize -= 0xFF;
          }
          tmpValue = binary(tmpSize);
          output.writeFully(&tmpValue, 1);
          SetSize_(GetSize() + 1);
        }
        break;
      case LACING_EBML:
        // number of laces
        tmpValue = myBuffers.size()-1;
        output.writeFully(&tmpValue, 1);
        {
          int64 _Size;
          int _CodedSize;
          binary _FinalHead[8]; // 64 bits max coded size

          _Size = myBuffers[0]->Size();

          _CodedSize = CodedSizeLength(_Size, 0, IsFiniteSize());

          // first size in the lace is not a signed
          CodedValueLength(_Size, _CodedSize, _FinalHead);
          output.writeFully(_FinalHead, _CodedSize);
          SetSize_(GetSize() + _CodedSize);

          // set the size of each member in the lace
          for (i=1; i<myBuffers.size()-1; i++) {
            _Size = int64(myBuffers[i]->Size()) - int64(myBuffers[i-1]->Size());
            _CodedSize = CodedSizeLengthSigned(_Size, 0);
            CodedValueLengthSigned(_Size, _CodedSize, _FinalHead);
            output.writeFully(_FinalHead, _CodedSize);
            SetSize_(GetSize() + _CodedSize);
          }
        }
        break;
      case LACING_FIXED:
        // number of laces
        tmpValue = myBuffers.size()-1;
        output.writeFully(&tmpValue, 1);
        break;
      case LACING_NONE:
        break;
      default:
        assert(0);
    }

    // put the data of each frame
    for (i=0; i<myBuffers.size(); i++) {
      output.writeFully(myBuffers[i]->Buffer(), myBuffers[i]->Size());
      SetSize_(GetSize() + myBuffers[i]->Size());
    }
  }

  return GetSize();
}

uint64 KaxInternalBlock::ReadInternalHead(IOCallback & input)
{
  binary Buffer[5], *cursor = Buffer;
  uint64 Result = input.read(cursor, 4);
  if (Result != 4)
    return Result;

  // update internal values
  TrackNumber = *cursor++;
  if ((TrackNumber & 0x80) == 0) {
    // there is extra data
    if ((TrackNumber & 0x40) == 0) {
      // We don't support track numbers that large !
      return Result;
    }
    Result += input.read(&Buffer[4], 1);
    TrackNumber = (TrackNumber & 0x3F) << 8;
    TrackNumber += *cursor++;
  } else {
    TrackNumber &= 0x7F;
  }


  big_int16 b16;
  b16.Eval(cursor);
  assert(ParentCluster != NULL);
  Timecode = ParentCluster->GetBlockGlobalTimecode(int16(b16));
  bLocalTimecodeUsed = false;
  cursor += 2;

  return Result;
}

/*!
  \todo better zero copy handling
*/
filepos_t KaxInternalBlock::ReadData(IOCallback & input, ScopeMode ReadFully)
{
  filepos_t Result;

  FirstFrameLocation = input.getFilePointer(); // will be updated accordingly below

  SetValueIsSet(false);

  try {
    if (ReadFully == SCOPE_ALL_DATA) {
      Result = EbmlBinary::ReadData(input, ReadFully);
      if (Result != GetSize())
        throw SafeReadIOCallback::EndOfStreamX(GetSize() - Result);

      binary *BufferStart = EbmlBinary::GetBuffer();

      SafeReadIOCallback Mem(*this);
      uint8 BlockHeadSize = 4;

      // update internal values
      TrackNumber = Mem.GetUInt8();
      if ((TrackNumber & 0x80) == 0) {
        // there is extra data
        if ((TrackNumber & 0x40) == 0) {
          // We don't support track numbers that large !
          throw SafeReadIOCallback::EndOfStreamX(0);
        }
        TrackNumber = (TrackNumber & 0x3F) << 8;
        TrackNumber += Mem.GetUInt8();
        BlockHeadSize++;
      } else {
        TrackNumber &= 0x7F;
      }

      LocalTimecode = int16(Mem.GetUInt16BE());
      bLocalTimecodeUsed = true;

      uint8 Flags = Mem.GetUInt8();
      if (EbmlId(*this) == EBML_ID(KaxSimpleBlock)) {
        bIsKeyframe = (Flags & 0x80) != 0;
        bIsDiscardable = (Flags & 0x01) != 0;
      }
      mInvisible = (Flags & 0x08) >> 3;
      mLacing = LacingType((Flags & 0x06) >> 1);

      // put all Frames in the list
      if (mLacing == LACING_NONE) {
        FirstFrameLocation += Mem.GetPosition();
        DataBuffer * soloFrame = new DataBuffer(BufferStart + Mem.GetPosition(), GetSize() - BlockHeadSize);
        myBuffers.push_back(soloFrame);
        SizeList.resize(1);
        SizeList[0] = GetSize() - BlockHeadSize;
      } else {
        // read the number of frames in the lace
        uint32 LastBufferSize = GetSize() - BlockHeadSize - 1; // 1 for number of frame
        uint8 FrameNum = Mem.GetUInt8(); // number of frames in the lace - 1
        // read the list of frame sizes
        uint8 Index;
        int32 FrameSize;
        uint32 SizeRead;
        uint64 SizeUnknown;

        SizeList.resize(FrameNum + 1);

        switch (mLacing) {
          case LACING_XIPH:
            for (Index=0; Index<FrameNum; Index++) {
              // get the size of the frame
              FrameSize = 0;
              uint8 Value;
              do {
                Value = Mem.GetUInt8();
                FrameSize += Value;
                LastBufferSize--;
              } while (Value == 0xFF);
              SizeList[Index] = FrameSize;
              LastBufferSize -= FrameSize;
            }
            SizeList[Index] = LastBufferSize;
            break;
          case LACING_EBML:
            SizeRead = LastBufferSize;
            FrameSize = ReadCodedSizeValue(BufferStart + Mem.GetPosition(), SizeRead, SizeUnknown);
            SizeList[0] = FrameSize;
            Mem.Skip(SizeRead);
            LastBufferSize -= FrameSize + SizeRead;

            for (Index=1; Index<FrameNum; Index++) {
              // get the size of the frame
              SizeRead = LastBufferSize;
              FrameSize += ReadCodedSizeSignedValue(BufferStart + Mem.GetPosition(), SizeRead, SizeUnknown);
              SizeList[Index] = FrameSize;
              Mem.Skip(SizeRead);
              LastBufferSize -= FrameSize + SizeRead;
            }
            if (Index <= FrameNum) // Safety check if FrameNum == 0
              SizeList[Index] = LastBufferSize;
            break;
          case LACING_FIXED:
            for (Index=0; Index<=FrameNum; Index++) {
              // get the size of the frame
              SizeList[Index] = LastBufferSize / (FrameNum + 1);
            }
            break;
          default: // other lacing not supported
            assert(0);
        }

        FirstFrameLocation += Mem.GetPosition();

        for (Index=0; Index<=FrameNum; Index++) {
          DataBuffer * lacedFrame = new DataBuffer(BufferStart + Mem.GetPosition(), SizeList[Index]);
          myBuffers.push_back(lacedFrame);
          Mem.Skip(SizeList[Index]);
        }
      }

      binary *BufferEnd = BufferStart + GetSize();
      size_t NumFrames  = myBuffers.size();

      // Sanity checks for frame pointers and boundaries.
      for (size_t Index = 0; Index < NumFrames; ++Index) {
        binary *FrameStart  = myBuffers[Index]->Buffer();
        binary *FrameEnd    = FrameStart + myBuffers[Index]->Size();
        binary *ExpectedEnd = (Index + 1) < NumFrames ? myBuffers[Index + 1]->Buffer() : BufferEnd;

        if ((FrameStart < BufferStart) || (FrameEnd > BufferEnd) || (FrameEnd != ExpectedEnd))
          throw SafeReadIOCallback::EndOfStreamX(0);
      }

      SetValueIsSet();
    } else if (ReadFully == SCOPE_PARTIAL_DATA) {
      binary _TempHead[5];
      Result = input.read(_TempHead, 5);
      if (Result != 5)
        throw SafeReadIOCallback::EndOfStreamX(0);
      binary *cursor = _TempHead;
      binary *_tmpBuf;
      uint8 BlockHeadSize = 4;

      // update internal values
      TrackNumber = *cursor++;
      if ((TrackNumber & 0x80) == 0) {
        // there is extra data
        if ((TrackNumber & 0x40) == 0) {
          // We don't support track numbers that large !
          return Result;
        }
        TrackNumber = (TrackNumber & 0x3F) << 8;
        TrackNumber += *cursor++;
        BlockHeadSize++;
      } else {
        TrackNumber &= 0x7F;
      }

      big_int16 b16;
      b16.Eval(cursor);
      LocalTimecode = int16(b16);
      bLocalTimecodeUsed = true;
      cursor += 2;

      if (EbmlId(*this) == EBML_ID(KaxSimpleBlock)) {
        bIsKeyframe = (*cursor & 0x80) != 0;
        bIsDiscardable = (*cursor & 0x01) != 0;
      }
      mInvisible = (*cursor & 0x08) >> 3;
      mLacing = LacingType((*cursor++ & 0x06) >> 1);
      if (cursor == &_TempHead[4]) {
        _TempHead[0] = _TempHead[4];
      } else {
        Result += input.read(_TempHead, 1);
      }

      FirstFrameLocation += cursor - _TempHead;

      // put all Frames in the list
      if (mLacing != LACING_NONE) {
        // read the number of frames in the lace
        uint32 LastBufferSize = GetSize() - BlockHeadSize - 1; // 1 for number of frame
        uint8 FrameNum = _TempHead[0]; // number of frames in the lace - 1
        // read the list of frame sizes
        uint8 Index;
        int32 FrameSize;
        uint32 SizeRead;
        uint64 SizeUnknown;

        SizeList.resize(FrameNum + 1);

        switch (mLacing) {
          case LACING_XIPH:
            for (Index=0; Index<FrameNum; Index++) {
              // get the size of the frame
              FrameSize = 0;
              do {
                Result += input.read(_TempHead, 1);
                FrameSize += uint8(_TempHead[0]);
                LastBufferSize--;

                FirstFrameLocation++;
              } while (_TempHead[0] == 0xFF);

              FirstFrameLocation++;
              SizeList[Index] = FrameSize;
              LastBufferSize -= FrameSize;
            }
            SizeList[Index] = LastBufferSize;
            break;
          case LACING_EBML:
            SizeRead = LastBufferSize;
            cursor = _tmpBuf = new binary[FrameNum*4]; /// \warning assume the mean size will be coded in less than 4 bytes
            Result += input.read(cursor, FrameNum*4);
            FrameSize = ReadCodedSizeValue(cursor, SizeRead, SizeUnknown);
            SizeList[0] = FrameSize;
            cursor += SizeRead;
            LastBufferSize -= FrameSize + SizeRead;

            for (Index=1; Index<FrameNum; Index++) {
              // get the size of the frame
              SizeRead = LastBufferSize;
              FrameSize += ReadCodedSizeSignedValue(cursor, SizeRead, SizeUnknown);
              SizeList[Index] = FrameSize;
              cursor += SizeRead;
              LastBufferSize -= FrameSize + SizeRead;
            }

            FirstFrameLocation += cursor - _tmpBuf;

            SizeList[Index] = LastBufferSize;
            delete [] _tmpBuf;
            break;
          case LACING_FIXED:
            for (Index=0; Index<=FrameNum; Index++) {
              // get the size of the frame
              SizeList[Index] = LastBufferSize / (FrameNum + 1);
            }
            break;
          default: // other lacing not supported
            assert(0);
        }
      } else {
        SizeList.resize(1);
        SizeList[0] = GetSize() - BlockHeadSize;
      }
      SetValueIsSet(false);
      Result = GetSize();
    } else {
      SetValueIsSet(false);
      Result = GetSize();
    }

  } catch (SafeReadIOCallback::EndOfStreamX &) {
    SetValueIsSet(false);

    std::memset(EbmlBinary::GetBuffer(), 0, GetSize());
    myBuffers.clear();
    SizeList.clear();
    Timecode           = 0;
    LocalTimecode      = 0;
    TrackNumber        = 0;
    bLocalTimecodeUsed = false;
    FirstFrameLocation = 0;

    return 0;
  }

  return Result;
}

bool KaxBlockGroup::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, LacingType lacing)
{
  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  assert(ParentCluster != NULL);
  theBlock.SetParent(*ParentCluster);
  ParentTrack = &track;
  return theBlock.AddFrame(track, timecode, buffer, lacing);
}

bool KaxBlockGroup::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, const KaxBlockGroup & PastBlock, LacingType lacing)
{
  //  assert(past_timecode < 0);

  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  assert(ParentCluster != NULL);
  theBlock.SetParent(*ParentCluster);
  ParentTrack = &track;
  bool bRes = theBlock.AddFrame(track, timecode, buffer, lacing);

  KaxReferenceBlock & thePastRef = GetChild<KaxReferenceBlock>(*this);
  thePastRef.SetReferencedBlock(PastBlock);
  thePastRef.SetParentBlock(*this);

  return bRes;
}

bool KaxBlockGroup::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, const KaxBlockGroup & PastBlock, const KaxBlockGroup & ForwBlock, LacingType lacing)
{
  //  assert(past_timecode < 0);

  //  assert(forw_timecode > 0);

  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  assert(ParentCluster != NULL);
  theBlock.SetParent(*ParentCluster);
  ParentTrack = &track;
  bool bRes = theBlock.AddFrame(track, timecode, buffer, lacing);

  KaxReferenceBlock & thePastRef = GetChild<KaxReferenceBlock>(*this);
  thePastRef.SetReferencedBlock(PastBlock);
  thePastRef.SetParentBlock(*this);

  KaxReferenceBlock & theFutureRef = AddNewChild<KaxReferenceBlock>(*this);
  theFutureRef.SetReferencedBlock(ForwBlock);
  theFutureRef.SetParentBlock(*this);

  return bRes;
}

bool KaxBlockGroup::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, const KaxBlockBlob * PastBlock, const KaxBlockBlob * ForwBlock, LacingType lacing)
{
  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  assert(ParentCluster != NULL);
  theBlock.SetParent(*ParentCluster);
  ParentTrack = &track;
  bool bRes = theBlock.AddFrame(track, timecode, buffer, lacing);

  if (PastBlock != NULL) {
    KaxReferenceBlock & thePastRef = GetChild<KaxReferenceBlock>(*this);
    thePastRef.SetReferencedBlock(PastBlock);
    thePastRef.SetParentBlock(*this);
  }

  if (ForwBlock != NULL) {
    KaxReferenceBlock & theFutureRef = AddNewChild<KaxReferenceBlock>(*this);
    theFutureRef.SetReferencedBlock(ForwBlock);
    theFutureRef.SetParentBlock(*this);
  }

  return bRes;
}

/*!
  \todo we may cache the reference to the timecode block
*/
uint64 KaxBlockGroup::GlobalTimecode() const
{
  assert(ParentCluster != NULL); // impossible otherwise
  KaxInternalBlock & MyBlock = *static_cast<KaxBlock *>(this->FindElt(EBML_INFO(KaxBlock)));
  return MyBlock.GlobalTimecode();

}

uint16 KaxBlockGroup::TrackNumber() const
{
  KaxInternalBlock & MyBlock = *static_cast<KaxBlock *>(this->FindElt(EBML_INFO(KaxBlock)));
  return MyBlock.TrackNum();
}

uint64 KaxBlockGroup::ClusterPosition() const
{
  assert(ParentCluster != NULL); // impossible otherwise
  return ParentCluster->GetPosition();
}

uint64 KaxInternalBlock::ClusterPosition() const
{
  assert(ParentCluster != NULL); // impossible otherwise
  return ParentCluster->GetPosition();
}

unsigned int KaxBlockGroup::ReferenceCount() const
{
  unsigned int Result = 0;
  KaxReferenceBlock * MyBlockAdds = static_cast<KaxReferenceBlock *>(FindFirstElt(EBML_INFO(KaxReferenceBlock)));
  if (MyBlockAdds != NULL) {
    Result++;
    while ((MyBlockAdds = static_cast<KaxReferenceBlock *>(FindNextElt(*MyBlockAdds))) != NULL) {
      Result++;
    }
  }
  return Result;
}

const KaxReferenceBlock & KaxBlockGroup::Reference(unsigned int Index) const
{
  KaxReferenceBlock * MyBlockAdds = static_cast<KaxReferenceBlock *>(FindFirstElt(EBML_INFO(KaxReferenceBlock)));
  assert(MyBlockAdds != NULL); // call of a non existing reference

  while (Index != 0) {
    MyBlockAdds = static_cast<KaxReferenceBlock *>(FindNextElt(*MyBlockAdds));
    assert(MyBlockAdds != NULL);
    Index--;
  }
  return *MyBlockAdds;
}

void KaxBlockGroup::ReleaseFrames()
{
  KaxInternalBlock & MyBlock = *static_cast<KaxBlock *>(this->FindElt(EBML_INFO(KaxBlock)));
  MyBlock.ReleaseFrames();
}

void KaxInternalBlock::ReleaseFrames()
{
  // free the allocated Frames
  int i;
  for (i=myBuffers.size()-1; i>=0; i--) {
    if (myBuffers[i] != NULL) {
      myBuffers[i]->FreeBuffer(*myBuffers[i]);
      delete myBuffers[i];
      myBuffers[i] = NULL;
    }
  }
}

void KaxBlockGroup::SetBlockDuration(uint64 TimeLength)
{
  assert(ParentTrack != NULL);
  int64 scale = ParentTrack->GlobalTimecodeScale();
  KaxBlockDuration & myDuration = *static_cast<KaxBlockDuration *>(FindFirstElt(EBML_INFO(KaxBlockDuration), true));
  *(static_cast<EbmlUInteger *>(&myDuration)) = TimeLength / uint64(scale);
}

bool KaxBlockGroup::GetBlockDuration(uint64 &TheTimecode) const
{
  KaxBlockDuration * myDuration = static_cast<KaxBlockDuration *>(FindElt(EBML_INFO(KaxBlockDuration)));
  if (myDuration == NULL) {
    return false;
  }

  assert(ParentTrack != NULL);
  TheTimecode = uint64(*myDuration) * ParentTrack->GlobalTimecodeScale();
  return true;
}

KaxBlockGroup::operator KaxInternalBlock &() {
  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  return theBlock;
}

void KaxBlockGroup::SetParent(KaxCluster & aParentCluster) {
  ParentCluster = &aParentCluster;
  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  theBlock.SetParent( aParentCluster );
}

void KaxSimpleBlock::SetParent(KaxCluster & aParentCluster) {
  KaxInternalBlock::SetParent( aParentCluster );
}

void KaxInternalBlock::SetParent(KaxCluster & aParentCluster)
{
  ParentCluster = &aParentCluster;
  if (bLocalTimecodeUsed) {
    Timecode = aParentCluster.GetBlockGlobalTimecode(LocalTimecode);
    bLocalTimecodeUsed = false;
  }
}

int64 KaxInternalBlock::GetDataPosition(size_t FrameNumber)
{
  int64 _Result = -1;

  if (ValueIsSet() && FrameNumber < SizeList.size()) {
    _Result = FirstFrameLocation;

    size_t _Idx = 0;
    while(FrameNumber--) {
      _Result += SizeList[_Idx++];
    }
  }

  return _Result;
}

int64 KaxInternalBlock::GetFrameSize(size_t FrameNumber)
{
  int64 _Result = -1;

  if (/*bValueIsSet &&*/ FrameNumber < SizeList.size()) {
    _Result = SizeList[FrameNumber];
  }

  return _Result;
}

KaxBlockBlob::operator KaxBlockGroup &()
{
  assert(!bUseSimpleBlock);
  assert(Block.group);
  return *Block.group;
}

KaxBlockBlob::operator const KaxBlockGroup &() const
{
  assert(!bUseSimpleBlock);
  assert(Block.group);
  return *Block.group;
}

KaxBlockBlob::operator KaxInternalBlock &()
{
  assert(Block.group);
#if MATROSKA_VERSION >= 2
  if (bUseSimpleBlock)
    return *Block.simpleblock;
  else
#endif
    return *Block.group;
}

KaxBlockBlob::operator const KaxInternalBlock &() const
{
  assert(Block.group);
#if MATROSKA_VERSION >= 2
  if (bUseSimpleBlock)
    return *Block.simpleblock;
  else
#endif
    return *Block.group;
}

#if MATROSKA_VERSION >= 2
KaxBlockBlob::operator KaxSimpleBlock &()
{
  assert(bUseSimpleBlock);
  assert(Block.simpleblock);
  return *Block.simpleblock;
}
#endif

bool KaxBlockBlob::AddFrameAuto(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, LacingType lacing, const KaxBlockBlob * PastBlock, const KaxBlockBlob * ForwBlock)
{
  bool bResult = false;
#if MATROSKA_VERSION >= 2
  if ((SimpleBlockMode == BLOCK_BLOB_ALWAYS_SIMPLE) || (SimpleBlockMode == BLOCK_BLOB_SIMPLE_AUTO && PastBlock == NULL && ForwBlock == NULL)) {
    assert(bUseSimpleBlock == true);
    if (Block.simpleblock == NULL) {
      Block.simpleblock = new KaxSimpleBlock();
      Block.simpleblock->SetParent(*ParentCluster);
    }

    bResult = Block.simpleblock->AddFrame(track, timecode, buffer, lacing);
    if (PastBlock == NULL && ForwBlock == NULL) {
      Block.simpleblock->SetKeyframe(true);
      Block.simpleblock->SetDiscardable(false);
    } else {
      Block.simpleblock->SetKeyframe(false);
      if ((ForwBlock == NULL || ((const KaxInternalBlock &)*ForwBlock).GlobalTimecode() <= timecode) &&
          (PastBlock == NULL || ((const KaxInternalBlock &)*PastBlock).GlobalTimecode() <= timecode))
        Block.simpleblock->SetDiscardable(false);
      else
        Block.simpleblock->SetDiscardable(true);
    }
  }
  else
#endif
    if (ReplaceSimpleByGroup())
      bResult = Block.group->AddFrame(track, timecode, buffer, PastBlock, ForwBlock, lacing);

  return bResult;
}

void KaxBlockBlob::SetParent(KaxCluster & parent_clust)
{
  ParentCluster = &parent_clust;
}

void KaxBlockBlob::SetBlockDuration(uint64 TimeLength)
{
  if (ReplaceSimpleByGroup())
    Block.group->SetBlockDuration(TimeLength);
}

bool KaxBlockBlob::ReplaceSimpleByGroup()
{
  if (SimpleBlockMode== BLOCK_BLOB_ALWAYS_SIMPLE)
    return false;

  if (!bUseSimpleBlock) {
    if (Block.group == NULL) {
      Block.group = new KaxBlockGroup();
    }
  }
#if MATROSKA_VERSION >= 2
  else {

    if (Block.simpleblock != NULL) {
      KaxSimpleBlock *old_simpleblock = Block.simpleblock;
      Block.group = new KaxBlockGroup();
      // _TODO_ : move all the data to the blockgroup
      assert(false);
      // -> while(frame) AddFrame(myBuffer)
      delete old_simpleblock;
    } else {
      Block.group = new KaxBlockGroup();
    }
  }
#endif
  if (ParentCluster != NULL)
    Block.group->SetParent(*ParentCluster);

  bUseSimpleBlock = false;
  return true;
}

void KaxBlockBlob::SetBlockGroup( KaxBlockGroup &BlockRef )
{
  assert(!bUseSimpleBlock);
  Block.group = &BlockRef;
}

filepos_t KaxBlockVirtual::ReadData(IOCallback & input, ScopeMode /* ReadFully */)
{
  input.setFilePointer(SizePosition + CodedSizeLength(Size, SizeLength, bSizeIsFinite) + Size, seek_beginning);
  return GetSize();
}

END_LIBMATROSKA_NAMESPACE


Fixed version (ground truth):
/****************************************************************************
** libmatroska : parse Matroska files, see http://www.matroska.org/
**
** <file/class description>
**
** Copyright (C) 2002-2010 Steve Lhomme.  All rights reserved.
**
** This library is free software; you can redistribute it and/or
** modify it under the terms of the GNU Lesser General Public
** License as published by the Free Software Foundation; either
** version 2.1 of the License, or (at your option) any later version.
**
** This library is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** Lesser General Public License for more details.
**
** You should have received a copy of the GNU Lesser General Public
** License along with this library; if not, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
**
** See http://www.gnu.org/licenses/lgpl-2.1.html for LGPL licensing information.**
** Contact license@matroska.org if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/

/*!
  \file
  \version \$Id: KaxBlock.cpp 1265 2007-01-14 17:20:35Z mosu $
  \author Steve Lhomme     <robux4 @ users.sf.net>
  \author Julien Coloos    <suiryc @ users.sf.net>
  \author Moritz Bunkus <moritz@bunkus.org>
*/
#include <cassert>

//#include <streams.h>

#include "ebml/MemReadIOCallback.h"
#include "ebml/SafeReadIOCallback.h"
#include "matroska/KaxBlock.h"
#include "matroska/KaxContexts.h"
#include "matroska/KaxBlockData.h"
#include "matroska/KaxCluster.h"
#include "matroska/KaxDefines.h"

START_LIBMATROSKA_NAMESPACE

DataBuffer * DataBuffer::Clone()
{
  binary *ClonedData = (binary *)malloc(mySize * sizeof(binary));
  assert(ClonedData != NULL);
  memcpy(ClonedData, myBuffer ,mySize );

  SimpleDataBuffer * result = new SimpleDataBuffer(ClonedData, mySize, 0);
  result->bValidValue = bValidValue;
  return result;
}

SimpleDataBuffer::SimpleDataBuffer(const SimpleDataBuffer & ToClone)
  :DataBuffer((binary *)malloc(ToClone.mySize * sizeof(binary)), ToClone.mySize, myFreeBuffer)
{
  assert(myBuffer != NULL);
  memcpy(myBuffer, ToClone.myBuffer ,mySize );
  bValidValue = ToClone.bValidValue;
}

bool KaxInternalBlock::ValidateSize() const
{
  return (GetSize() >= 4); /// for the moment
}

KaxInternalBlock::~KaxInternalBlock()
{
  ReleaseFrames();
}

KaxInternalBlock::KaxInternalBlock(const KaxInternalBlock & ElementToClone)
  :EbmlBinary(ElementToClone)
  ,myBuffers(ElementToClone.myBuffers.size())
  ,Timecode(ElementToClone.Timecode)
  ,LocalTimecode(ElementToClone.LocalTimecode)
  ,bLocalTimecodeUsed(ElementToClone.bLocalTimecodeUsed)
  ,TrackNumber(ElementToClone.TrackNumber)
  ,ParentCluster(ElementToClone.ParentCluster) ///< \todo not exactly
{
  // add a clone of the list
  std::vector<DataBuffer *>::const_iterator Itr = ElementToClone.myBuffers.begin();
  std::vector<DataBuffer *>::iterator myItr = myBuffers.begin();
  while (Itr != ElementToClone.myBuffers.end()) {
    *myItr = (*Itr)->Clone();
    ++Itr; ++myItr;
  }
}


KaxBlockGroup::~KaxBlockGroup()
{
  //NOTE("KaxBlockGroup::~KaxBlockGroup");
}

KaxBlockGroup::KaxBlockGroup(EBML_EXTRA_DEF)
  :EbmlMaster(EBML_CLASS_SEMCONTEXT(KaxBlockGroup) EBML_DEF_SEP EBML_EXTRA_CALL)
  ,ParentCluster(NULL)
  ,ParentTrack(NULL)
{}

/*!
  \todo handle flags
  \todo hardcoded limit of the number of frames in a lace should be a parameter
  \return true if more frames can be added to this Block
*/
bool KaxInternalBlock::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, LacingType lacing, bool invisible)
{
  SetValueIsSet();
  if (myBuffers.size() == 0) {
    // first frame
    Timecode = timecode;
    TrackNumber = track.TrackNumber();
    mInvisible = invisible;
    mLacing = lacing;
  }
  myBuffers.push_back(&buffer);

  // we don't allow more than 8 frames in a Block because the overhead improvement is minimal
  if (myBuffers.size() >= 8 || lacing == LACING_NONE)
    return false;

  if (lacing == LACING_XIPH)
    // decide wether a new frame can be added or not
    // a frame in a lace is not efficient when the place necessary to code it in a lace is bigger
    // than the size of a simple Block. That means more than 6 bytes (4 in struct + 2 for EBML) to code the size
    return (buffer.Size() < 6*0xFF);
  else
    return true;
}

/*!
  \return Returns the lacing type that produces the smallest footprint.
*/
LacingType KaxInternalBlock::GetBestLacingType() const {
  int XiphLacingSize, EbmlLacingSize, i;
  bool SameSize = true;

  if (myBuffers.size() <= 1)
    return LACING_NONE;

  XiphLacingSize = 1; // Number of laces is stored in 1 byte.
  EbmlLacingSize = 1;
  for (i = 0; i < (int)myBuffers.size() - 1; i++) {
    if (myBuffers[i]->Size() != myBuffers[i + 1]->Size())
      SameSize = false;
    XiphLacingSize += myBuffers[i]->Size() / 255 + 1;
  }
  EbmlLacingSize += CodedSizeLength(myBuffers[0]->Size(), 0, IsFiniteSize());
  for (i = 1; i < (int)myBuffers.size() - 1; i++)
    EbmlLacingSize += CodedSizeLengthSigned(int64(myBuffers[i]->Size()) - int64(myBuffers[i - 1]->Size()), 0);
  if (SameSize)
    return LACING_FIXED;
  else if (XiphLacingSize < EbmlLacingSize)
    return LACING_XIPH;
  else
    return LACING_EBML;
}

filepos_t KaxInternalBlock::UpdateSize(bool /* bSaveDefault */, bool /* bForceRender */)
{
  LacingType LacingHere;
  assert(EbmlBinary::GetBuffer() == NULL); // Data is not used for KaxInternalBlock
  assert(TrackNumber < 0x4000); // no more allowed for the moment
  unsigned int i;

  // compute the final size of the data
  switch (myBuffers.size()) {
    case 0:
      SetSize_(0);
      break;
    case 1:
      SetSize_(4 + myBuffers[0]->Size());
      break;
    default:
      SetSize_(4 + 1); // 1 for the lacing head
      if (mLacing == LACING_AUTO)
        LacingHere = GetBestLacingType();
      else
        LacingHere = mLacing;
      switch (LacingHere) {
        case LACING_XIPH:
          for (i=0; i<myBuffers.size()-1; i++) {
            SetSize_(GetSize() + myBuffers[i]->Size() + (myBuffers[i]->Size() / 0xFF + 1));
          }
          break;
        case LACING_EBML:
          SetSize_(GetSize() + myBuffers[0]->Size() + CodedSizeLength(myBuffers[0]->Size(), 0, IsFiniteSize()));
          for (i=1; i<myBuffers.size()-1; i++) {
            SetSize_(GetSize() + myBuffers[i]->Size() + CodedSizeLengthSigned(int64(myBuffers[i]->Size()) - int64(myBuffers[i-1]->Size()), 0));
          }
          break;
        case LACING_FIXED:
          for (i=0; i<myBuffers.size()-1; i++) {
            SetSize_(GetSize() + myBuffers[i]->Size());
          }
          break;
        default:
          i = 0;
          assert(0);
      }
      // Size of the last frame (not in lace)
      SetSize_(GetSize() + myBuffers[i]->Size());
      break;
  }

  if (TrackNumber >= 0x80)
    SetSize_(GetSize() + 1); // the size will be coded with one more octet

  return GetSize();
}

#if MATROSKA_VERSION >= 2
KaxBlockVirtual::KaxBlockVirtual(const KaxBlockVirtual & ElementToClone)
  :EbmlBinary(ElementToClone)
  ,Timecode(ElementToClone.Timecode)
  ,TrackNumber(ElementToClone.TrackNumber)
  ,ParentCluster(ElementToClone.ParentCluster) ///< \todo not exactly
{
  SetBuffer(DataBlock,sizeof(DataBlock));
  SetValueIsSet(false);
}

KaxBlockVirtual::KaxBlockVirtual(EBML_EXTRA_DEF)
  :EBML_DEF_BINARY(KaxBlockVirtual)EBML_DEF_SEP ParentCluster(NULL)
{
  SetBuffer(DataBlock,sizeof(DataBlock));
  SetValueIsSet(false);
}

KaxBlockVirtual::~KaxBlockVirtual()
{
  if(GetBuffer() == DataBlock)
    SetBuffer( NULL, 0 );
}

filepos_t KaxBlockVirtual::UpdateSize(bool /* bSaveDefault */, bool /* bForceRender */)
{
  assert(TrackNumber < 0x4000);
  binary *cursor = EbmlBinary::GetBuffer();
  // fill data
  if (TrackNumber < 0x80) {
    assert(GetSize() >= 4);
    *cursor++ = TrackNumber | 0x80; // set the first bit to 1
  } else {
    assert(GetSize() >= 5);
    *cursor++ = (TrackNumber >> 8) | 0x40; // set the second bit to 1
    *cursor++ = TrackNumber & 0xFF;
  }

  assert(ParentCluster != NULL);
  int16 ActualTimecode = ParentCluster->GetBlockLocalTimecode(Timecode);
  big_int16 b16(ActualTimecode);
  b16.Fill(cursor);
  cursor += 2;

  *cursor++ = 0; // flags

  return GetSize();
}
#endif // MATROSKA_VERSION

/*!
  \todo more optimisation is possible (render the Block head and don't copy the buffer in memory, care should be taken with the allocation of Data)
  \todo the actual timecode to write should be retrieved from the Cluster from here
*/
filepos_t KaxInternalBlock::RenderData(IOCallback & output, bool /* bForceRender */, bool /* bSaveDefault */)
{
  if (myBuffers.size() == 0) {
    return 0;
  } else {
    assert(TrackNumber < 0x4000);
    binary BlockHead[5], *cursor = BlockHead;
    unsigned int i;

    if (myBuffers.size() == 1) {
      SetSize_(4);
      mLacing = LACING_NONE;
    } else {
      if (mLacing == LACING_NONE)
        mLacing = LACING_EBML; // supposedly the best of all
      SetSize_(4 + 1); // 1 for the lacing head (number of laced elements)
    }
    if (TrackNumber > 0x80)
      SetSize_(GetSize() + 1);

    // write Block Head
    if (TrackNumber < 0x80) {
      *cursor++ = TrackNumber | 0x80; // set the first bit to 1
    } else {
      *cursor++ = (TrackNumber >> 8) | 0x40; // set the second bit to 1
      *cursor++ = TrackNumber & 0xFF;
    }

    assert(ParentCluster != NULL);
    int16 ActualTimecode = ParentCluster->GetBlockLocalTimecode(Timecode);
    big_int16 b16(ActualTimecode);
    b16.Fill(cursor);
    cursor += 2;

    *cursor = 0; // flags

    if (mLacing == LACING_AUTO) {
      mLacing = GetBestLacingType();
    }

    // invisible flag
    if (mInvisible)
      *cursor = 0x08;

    if (bIsSimple) {
      if (bIsKeyframe)
        *cursor |= 0x80;
      if (bIsDiscardable)
        *cursor |= 0x01;
    }

    // lacing flag
    switch (mLacing) {
      case LACING_XIPH:
        *cursor++ |= 0x02;
        break;
      case LACING_EBML:
        *cursor++ |= 0x06;
        break;
      case LACING_FIXED:
        *cursor++ |= 0x04;
        break;
      case LACING_NONE:
        break;
      default:
        assert(0);
    }

    output.writeFully(BlockHead, 4 + ((TrackNumber > 0x80) ? 1 : 0));

    binary tmpValue;
    switch (mLacing) {
      case LACING_XIPH:
        // number of laces
        tmpValue = myBuffers.size()-1;
        output.writeFully(&tmpValue, 1);

        // set the size of each member in the lace
        for (i=0; i<myBuffers.size()-1; i++) {
          tmpValue = 0xFF;
          uint16 tmpSize = myBuffers[i]->Size();
          while (tmpSize >= 0xFF) {
            output.writeFully(&tmpValue, 1);
            SetSize_(GetSize() + 1);
            tmpSize -= 0xFF;
          }
          tmpValue = binary(tmpSize);
          output.writeFully(&tmpValue, 1);
          SetSize_(GetSize() + 1);
        }
        break;
      case LACING_EBML:
        // number of laces
        tmpValue = myBuffers.size()-1;
        output.writeFully(&tmpValue, 1);
        {
          int64 _Size;
          int _CodedSize;
          binary _FinalHead[8]; // 64 bits max coded size

          _Size = myBuffers[0]->Size();

          _CodedSize = CodedSizeLength(_Size, 0, IsFiniteSize());

          // first size in the lace is not a signed
          CodedValueLength(_Size, _CodedSize, _FinalHead);
          output.writeFully(_FinalHead, _CodedSize);
          SetSize_(GetSize() + _CodedSize);

          // set the size of each member in the lace
          for (i=1; i<myBuffers.size()-1; i++) {
            _Size = int64(myBuffers[i]->Size()) - int64(myBuffers[i-1]->Size());
            _CodedSize = CodedSizeLengthSigned(_Size, 0);
            CodedValueLengthSigned(_Size, _CodedSize, _FinalHead);
            output.writeFully(_FinalHead, _CodedSize);
            SetSize_(GetSize() + _CodedSize);
          }
        }
        break;
      case LACING_FIXED:
        // number of laces
        tmpValue = myBuffers.size()-1;
        output.writeFully(&tmpValue, 1);
        break;
      case LACING_NONE:
        break;
      default:
        assert(0);
    }

    // put the data of each frame
    for (i=0; i<myBuffers.size(); i++) {
      output.writeFully(myBuffers[i]->Buffer(), myBuffers[i]->Size());
      SetSize_(GetSize() + myBuffers[i]->Size());
    }
  }

  return GetSize();
}

uint64 KaxInternalBlock::ReadInternalHead(IOCallback & input)
{
  binary Buffer[5], *cursor = Buffer;
  uint64 Result = input.read(cursor, 4);
  if (Result != 4)
    return Result;

  // update internal values
  TrackNumber = *cursor++;
  if ((TrackNumber & 0x80) == 0) {
    // there is extra data
    if ((TrackNumber & 0x40) == 0) {
      // We don't support track numbers that large !
      return Result;
    }
    Result += input.read(&Buffer[4], 1);
    TrackNumber = (TrackNumber & 0x3F) << 8;
    TrackNumber += *cursor++;
  } else {
    TrackNumber &= 0x7F;
  }


  big_int16 b16;
  b16.Eval(cursor);
  assert(ParentCluster != NULL);
  Timecode = ParentCluster->GetBlockGlobalTimecode(int16(b16));
  bLocalTimecodeUsed = false;
  cursor += 2;

  return Result;
}

/*!
  \todo better zero copy handling
*/
filepos_t KaxInternalBlock::ReadData(IOCallback & input, ScopeMode ReadFully)
{
  filepos_t Result;

  FirstFrameLocation = input.getFilePointer(); // will be updated accordingly below

  SetValueIsSet(false);

  try {
    if (ReadFully == SCOPE_ALL_DATA) {
      Result = EbmlBinary::ReadData(input, ReadFully);
      if (Result != GetSize())
        throw SafeReadIOCallback::EndOfStreamX(GetSize() - Result);

      binary *BufferStart = EbmlBinary::GetBuffer();

      SafeReadIOCallback Mem(*this);
      uint8 BlockHeadSize = 4;

      // update internal values
      TrackNumber = Mem.GetUInt8();
      if ((TrackNumber & 0x80) == 0) {
        // there is extra data
        if ((TrackNumber & 0x40) == 0) {
          // We don't support track numbers that large !
          throw SafeReadIOCallback::EndOfStreamX(0);
        }
        TrackNumber = (TrackNumber & 0x3F) << 8;
        TrackNumber += Mem.GetUInt8();
        BlockHeadSize++;
      } else {
        TrackNumber &= 0x7F;
      }

      LocalTimecode = int16(Mem.GetUInt16BE());
      bLocalTimecodeUsed = true;

      uint8 Flags = Mem.GetUInt8();
      if (EbmlId(*this) == EBML_ID(KaxSimpleBlock)) {
        bIsKeyframe = (Flags & 0x80) != 0;
        bIsDiscardable = (Flags & 0x01) != 0;
      }
      mInvisible = (Flags & 0x08) >> 3;
      mLacing = LacingType((Flags & 0x06) >> 1);

      // put all Frames in the list
      if (mLacing == LACING_NONE) {
        FirstFrameLocation += Mem.GetPosition();
        DataBuffer * soloFrame = new DataBuffer(BufferStart + Mem.GetPosition(), GetSize() - BlockHeadSize);
        myBuffers.push_back(soloFrame);
        SizeList.resize(1);
        SizeList[0] = GetSize() - BlockHeadSize;
      } else {
        // read the number of frames in the lace
        uint32 LastBufferSize = GetSize() - BlockHeadSize - 1; // 1 for number of frame
        uint8 FrameNum = Mem.GetUInt8(); // number of frames in the lace - 1
        // read the list of frame sizes
        uint8 Index;
        int32 FrameSize;
        uint32 SizeRead;
        uint64 SizeUnknown;

        SizeList.resize(FrameNum + 1);

        switch (mLacing) {
          case LACING_XIPH:
            for (Index=0; Index<FrameNum; Index++) {
              // get the size of the frame
              FrameSize = 0;
              uint8 Value;
              do {
                Value = Mem.GetUInt8();
                FrameSize += Value;
                LastBufferSize--;
              } while (Value == 0xFF);
              SizeList[Index] = FrameSize;
              LastBufferSize -= FrameSize;
            }
            SizeList[Index] = LastBufferSize;
            break;
          case LACING_EBML:
            SizeRead = LastBufferSize;
            FrameSize = ReadCodedSizeValue(BufferStart + Mem.GetPosition(), SizeRead, SizeUnknown);
            if (!FrameSize || (static_cast<uint32>(FrameSize + SizeRead) > LastBufferSize))
              throw SafeReadIOCallback::EndOfStreamX(SizeRead);
            SizeList[0] = FrameSize;
            Mem.Skip(SizeRead);
            LastBufferSize -= FrameSize + SizeRead;

            for (Index=1; Index<FrameNum; Index++) {
              // get the size of the frame
              SizeRead = LastBufferSize;
              FrameSize += ReadCodedSizeSignedValue(BufferStart + Mem.GetPosition(), SizeRead, SizeUnknown);
              if (!FrameSize || (static_cast<uint32>(FrameSize + SizeRead) > LastBufferSize))
                throw SafeReadIOCallback::EndOfStreamX(SizeRead);
              SizeList[Index] = FrameSize;
              Mem.Skip(SizeRead);
              LastBufferSize -= FrameSize + SizeRead;
            }
            if (Index <= FrameNum) // Safety check if FrameNum == 0
              SizeList[Index] = LastBufferSize;
            break;
          case LACING_FIXED:
            for (Index=0; Index<=FrameNum; Index++) {
              // get the size of the frame
              SizeList[Index] = LastBufferSize / (FrameNum + 1);
            }
            break;
          default: // other lacing not supported
            assert(0);
        }

        FirstFrameLocation += Mem.GetPosition();

        for (Index=0; Index<=FrameNum; Index++) {
          DataBuffer * lacedFrame = new DataBuffer(BufferStart + Mem.GetPosition(), SizeList[Index]);
          myBuffers.push_back(lacedFrame);
          Mem.Skip(SizeList[Index]);
        }
      }

      binary *BufferEnd = BufferStart + GetSize();
      size_t NumFrames  = myBuffers.size();

      // Sanity checks for frame pointers and boundaries.
      for (size_t Index = 0; Index < NumFrames; ++Index) {
        binary *FrameStart  = myBuffers[Index]->Buffer();
        binary *FrameEnd    = FrameStart + myBuffers[Index]->Size();
        binary *ExpectedEnd = (Index + 1) < NumFrames ? myBuffers[Index + 1]->Buffer() : BufferEnd;

        if ((FrameStart < BufferStart) || (FrameEnd > BufferEnd) || (FrameEnd != ExpectedEnd))
          throw SafeReadIOCallback::EndOfStreamX(0);
      }

      SetValueIsSet();
    } else if (ReadFully == SCOPE_PARTIAL_DATA) {
      binary _TempHead[5];
      Result = input.read(_TempHead, 5);
      if (Result != 5)
        throw SafeReadIOCallback::EndOfStreamX(0);
      binary *cursor = _TempHead;
      binary *_tmpBuf;
      uint8 BlockHeadSize = 4;

      // update internal values
      TrackNumber = *cursor++;
      if ((TrackNumber & 0x80) == 0) {
        // there is extra data
        if ((TrackNumber & 0x40) == 0) {
          // We don't support track numbers that large !
          return Result;
        }
        TrackNumber = (TrackNumber & 0x3F) << 8;
        TrackNumber += *cursor++;
        BlockHeadSize++;
      } else {
        TrackNumber &= 0x7F;
      }

      big_int16 b16;
      b16.Eval(cursor);
      LocalTimecode = int16(b16);
      bLocalTimecodeUsed = true;
      cursor += 2;

      if (EbmlId(*this) == EBML_ID(KaxSimpleBlock)) {
        bIsKeyframe = (*cursor & 0x80) != 0;
        bIsDiscardable = (*cursor & 0x01) != 0;
      }
      mInvisible = (*cursor & 0x08) >> 3;
      mLacing = LacingType((*cursor++ & 0x06) >> 1);
      if (cursor == &_TempHead[4]) {
        _TempHead[0] = _TempHead[4];
      } else {
        Result += input.read(_TempHead, 1);
      }

      FirstFrameLocation += cursor - _TempHead;

      // put all Frames in the list
      if (mLacing != LACING_NONE) {
        // read the number of frames in the lace
        uint32 LastBufferSize = GetSize() - BlockHeadSize - 1; // 1 for number of frame
        uint8 FrameNum = _TempHead[0]; // number of frames in the lace - 1
        // read the list of frame sizes
        uint8 Index;
        int32 FrameSize;
        uint32 SizeRead;
        uint64 SizeUnknown;

        SizeList.resize(FrameNum + 1);

        switch (mLacing) {
          case LACING_XIPH:
            for (Index=0; Index<FrameNum; Index++) {
              // get the size of the frame
              FrameSize = 0;
              do {
                Result += input.read(_TempHead, 1);
                FrameSize += uint8(_TempHead[0]);
                LastBufferSize--;

                FirstFrameLocation++;
              } while (_TempHead[0] == 0xFF);

              FirstFrameLocation++;
              SizeList[Index] = FrameSize;
              LastBufferSize -= FrameSize;
            }
            SizeList[Index] = LastBufferSize;
            break;
          case LACING_EBML:
            SizeRead = LastBufferSize;
            cursor = _tmpBuf = new binary[FrameNum*4]; /// \warning assume the mean size will be coded in less than 4 bytes
            Result += input.read(cursor, FrameNum*4);
            FrameSize = ReadCodedSizeValue(cursor, SizeRead, SizeUnknown);
            SizeList[0] = FrameSize;
            cursor += SizeRead;
            LastBufferSize -= FrameSize + SizeRead;

            for (Index=1; Index<FrameNum; Index++) {
              // get the size of the frame
              SizeRead = LastBufferSize;
              FrameSize += ReadCodedSizeSignedValue(cursor, SizeRead, SizeUnknown);
              SizeList[Index] = FrameSize;
              cursor += SizeRead;
              LastBufferSize -= FrameSize + SizeRead;
            }

            FirstFrameLocation += cursor - _tmpBuf;

            SizeList[Index] = LastBufferSize;
            delete [] _tmpBuf;
            break;
          case LACING_FIXED:
            for (Index=0; Index<=FrameNum; Index++) {
              // get the size of the frame
              SizeList[Index] = LastBufferSize / (FrameNum + 1);
            }
            break;
          default: // other lacing not supported
            assert(0);
        }
      } else {
        SizeList.resize(1);
        SizeList[0] = GetSize() - BlockHeadSize;
      }
      SetValueIsSet(false);
      Result = GetSize();
    } else {
      SetValueIsSet(false);
      Result = GetSize();
    }

  } catch (SafeReadIOCallback::EndOfStreamX &) {
    SetValueIsSet(false);

    std::memset(EbmlBinary::GetBuffer(), 0, GetSize());
    myBuffers.clear();
    SizeList.clear();
    Timecode           = 0;
    LocalTimecode      = 0;
    TrackNumber        = 0;
    bLocalTimecodeUsed = false;
    FirstFrameLocation = 0;

    return 0;
  }

  return Result;
}

bool KaxBlockGroup::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, LacingType lacing)
{
  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  assert(ParentCluster != NULL);
  theBlock.SetParent(*ParentCluster);
  ParentTrack = &track;
  return theBlock.AddFrame(track, timecode, buffer, lacing);
}

bool KaxBlockGroup::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, const KaxBlockGroup & PastBlock, LacingType lacing)
{
  //  assert(past_timecode < 0);

  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  assert(ParentCluster != NULL);
  theBlock.SetParent(*ParentCluster);
  ParentTrack = &track;
  bool bRes = theBlock.AddFrame(track, timecode, buffer, lacing);

  KaxReferenceBlock & thePastRef = GetChild<KaxReferenceBlock>(*this);
  thePastRef.SetReferencedBlock(PastBlock);
  thePastRef.SetParentBlock(*this);

  return bRes;
}

bool KaxBlockGroup::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, const KaxBlockGroup & PastBlock, const KaxBlockGroup & ForwBlock, LacingType lacing)
{
  //  assert(past_timecode < 0);

  //  assert(forw_timecode > 0);

  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  assert(ParentCluster != NULL);
  theBlock.SetParent(*ParentCluster);
  ParentTrack = &track;
  bool bRes = theBlock.AddFrame(track, timecode, buffer, lacing);

  KaxReferenceBlock & thePastRef = GetChild<KaxReferenceBlock>(*this);
  thePastRef.SetReferencedBlock(PastBlock);
  thePastRef.SetParentBlock(*this);

  KaxReferenceBlock & theFutureRef = AddNewChild<KaxReferenceBlock>(*this);
  theFutureRef.SetReferencedBlock(ForwBlock);
  theFutureRef.SetParentBlock(*this);

  return bRes;
}

bool KaxBlockGroup::AddFrame(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, const KaxBlockBlob * PastBlock, const KaxBlockBlob * ForwBlock, LacingType lacing)
{
  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  assert(ParentCluster != NULL);
  theBlock.SetParent(*ParentCluster);
  ParentTrack = &track;
  bool bRes = theBlock.AddFrame(track, timecode, buffer, lacing);

  if (PastBlock != NULL) {
    KaxReferenceBlock & thePastRef = GetChild<KaxReferenceBlock>(*this);
    thePastRef.SetReferencedBlock(PastBlock);
    thePastRef.SetParentBlock(*this);
  }

  if (ForwBlock != NULL) {
    KaxReferenceBlock & theFutureRef = AddNewChild<KaxReferenceBlock>(*this);
    theFutureRef.SetReferencedBlock(ForwBlock);
    theFutureRef.SetParentBlock(*this);
  }

  return bRes;
}

/*!
  \todo we may cache the reference to the timecode block
*/
uint64 KaxBlockGroup::GlobalTimecode() const
{
  assert(ParentCluster != NULL); // impossible otherwise
  KaxInternalBlock & MyBlock = *static_cast<KaxBlock *>(this->FindElt(EBML_INFO(KaxBlock)));
  return MyBlock.GlobalTimecode();

}

uint16 KaxBlockGroup::TrackNumber() const
{
  KaxInternalBlock & MyBlock = *static_cast<KaxBlock *>(this->FindElt(EBML_INFO(KaxBlock)));
  return MyBlock.TrackNum();
}

uint64 KaxBlockGroup::ClusterPosition() const
{
  assert(ParentCluster != NULL); // impossible otherwise
  return ParentCluster->GetPosition();
}

uint64 KaxInternalBlock::ClusterPosition() const
{
  assert(ParentCluster != NULL); // impossible otherwise
  return ParentCluster->GetPosition();
}

unsigned int KaxBlockGroup::ReferenceCount() const
{
  unsigned int Result = 0;
  KaxReferenceBlock * MyBlockAdds = static_cast<KaxReferenceBlock *>(FindFirstElt(EBML_INFO(KaxReferenceBlock)));
  if (MyBlockAdds != NULL) {
    Result++;
    while ((MyBlockAdds = static_cast<KaxReferenceBlock *>(FindNextElt(*MyBlockAdds))) != NULL) {
      Result++;
    }
  }
  return Result;
}

const KaxReferenceBlock & KaxBlockGroup::Reference(unsigned int Index) const
{
  KaxReferenceBlock * MyBlockAdds = static_cast<KaxReferenceBlock *>(FindFirstElt(EBML_INFO(KaxReferenceBlock)));
  assert(MyBlockAdds != NULL); // call of a non existing reference

  while (Index != 0) {
    MyBlockAdds = static_cast<KaxReferenceBlock *>(FindNextElt(*MyBlockAdds));
    assert(MyBlockAdds != NULL);
    Index--;
  }
  return *MyBlockAdds;
}

void KaxBlockGroup::ReleaseFrames()
{
  KaxInternalBlock & MyBlock = *static_cast<KaxBlock *>(this->FindElt(EBML_INFO(KaxBlock)));
  MyBlock.ReleaseFrames();
}

void KaxInternalBlock::ReleaseFrames()
{
  // free the allocated Frames
  int i;
  for (i=myBuffers.size()-1; i>=0; i--) {
    if (myBuffers[i] != NULL) {
      myBuffers[i]->FreeBuffer(*myBuffers[i]);
      delete myBuffers[i];
      myBuffers[i] = NULL;
    }
  }
}

void KaxBlockGroup::SetBlockDuration(uint64 TimeLength)
{
  assert(ParentTrack != NULL);
  int64 scale = ParentTrack->GlobalTimecodeScale();
  KaxBlockDuration & myDuration = *static_cast<KaxBlockDuration *>(FindFirstElt(EBML_INFO(KaxBlockDuration), true));
  *(static_cast<EbmlUInteger *>(&myDuration)) = TimeLength / uint64(scale);
}

bool KaxBlockGroup::GetBlockDuration(uint64 &TheTimecode) const
{
  KaxBlockDuration * myDuration = static_cast<KaxBlockDuration *>(FindElt(EBML_INFO(KaxBlockDuration)));
  if (myDuration == NULL) {
    return false;
  }

  assert(ParentTrack != NULL);
  TheTimecode = uint64(*myDuration) * ParentTrack->GlobalTimecodeScale();
  return true;
}

KaxBlockGroup::operator KaxInternalBlock &() {
  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  return theBlock;
}

void KaxBlockGroup::SetParent(KaxCluster & aParentCluster) {
  ParentCluster = &aParentCluster;
  KaxBlock & theBlock = GetChild<KaxBlock>(*this);
  theBlock.SetParent( aParentCluster );
}

void KaxSimpleBlock::SetParent(KaxCluster & aParentCluster) {
  KaxInternalBlock::SetParent( aParentCluster );
}

void KaxInternalBlock::SetParent(KaxCluster & aParentCluster)
{
  ParentCluster = &aParentCluster;
  if (bLocalTimecodeUsed) {
    Timecode = aParentCluster.GetBlockGlobalTimecode(LocalTimecode);
    bLocalTimecodeUsed = false;
  }
}

int64 KaxInternalBlock::GetDataPosition(size_t FrameNumber)
{
  int64 _Result = -1;

  if (ValueIsSet() && FrameNumber < SizeList.size()) {
    _Result = FirstFrameLocation;

    size_t _Idx = 0;
    while(FrameNumber--) {
      _Result += SizeList[_Idx++];
    }
  }

  return _Result;
}

int64 KaxInternalBlock::GetFrameSize(size_t FrameNumber)
{
  int64 _Result = -1;

  if (/*bValueIsSet &&*/ FrameNumber < SizeList.size()) {
    _Result = SizeList[FrameNumber];
  }

  return _Result;
}

KaxBlockBlob::operator KaxBlockGroup &()
{
  assert(!bUseSimpleBlock);
  assert(Block.group);
  return *Block.group;
}

KaxBlockBlob::operator const KaxBlockGroup &() const
{
  assert(!bUseSimpleBlock);
  assert(Block.group);
  return *Block.group;
}

KaxBlockBlob::operator KaxInternalBlock &()
{
  assert(Block.group);
#if MATROSKA_VERSION >= 2
  if (bUseSimpleBlock)
    return *Block.simpleblock;
  else
#endif
    return *Block.group;
}

KaxBlockBlob::operator const KaxInternalBlock &() const
{
  assert(Block.group);
#if MATROSKA_VERSION >= 2
  if (bUseSimpleBlock)
    return *Block.simpleblock;
  else
#endif
    return *Block.group;
}

#if MATROSKA_VERSION >= 2
KaxBlockBlob::operator KaxSimpleBlock &()
{
  assert(bUseSimpleBlock);
  assert(Block.simpleblock);
  return *Block.simpleblock;
}
#endif

bool KaxBlockBlob::AddFrameAuto(const KaxTrackEntry & track, uint64 timecode, DataBuffer & buffer, LacingType lacing, const KaxBlockBlob * PastBlock, const KaxBlockBlob * ForwBlock)
{
  bool bResult = false;
#if MATROSKA_VERSION >= 2
  if ((SimpleBlockMode == BLOCK_BLOB_ALWAYS_SIMPLE) || (SimpleBlockMode == BLOCK_BLOB_SIMPLE_AUTO && PastBlock == NULL && ForwBlock == NULL)) {
    assert(bUseSimpleBlock == true);
    if (Block.simpleblock == NULL) {
      Block.simpleblock = new KaxSimpleBlock();
      Block.simpleblock->SetParent(*ParentCluster);
    }

    bResult = Block.simpleblock->AddFrame(track, timecode, buffer, lacing);
    if (PastBlock == NULL && ForwBlock == NULL) {
      Block.simpleblock->SetKeyframe(true);
      Block.simpleblock->SetDiscardable(false);
    } else {
      Block.simpleblock->SetKeyframe(false);
      if ((ForwBlock == NULL || ((const KaxInternalBlock &)*ForwBlock).GlobalTimecode() <= timecode) &&
          (PastBlock == NULL || ((const KaxInternalBlock &)*PastBlock).GlobalTimecode() <= timecode))
        Block.simpleblock->SetDiscardable(false);
      else
        Block.simpleblock->SetDiscardable(true);
    }
  }
  else
#endif
    if (ReplaceSimpleByGroup())
      bResult = Block.group->AddFrame(track, timecode, buffer, PastBlock, ForwBlock, lacing);

  return bResult;
}

void KaxBlockBlob::SetParent(KaxCluster & parent_clust)
{
  ParentCluster = &parent_clust;
}

void KaxBlockBlob::SetBlockDuration(uint64 TimeLength)
{
  if (ReplaceSimpleByGroup())
    Block.group->SetBlockDuration(TimeLength);
}

bool KaxBlockBlob::ReplaceSimpleByGroup()
{
  if (SimpleBlockMode== BLOCK_BLOB_ALWAYS_SIMPLE)
    return false;

  if (!bUseSimpleBlock) {
    if (Block.group == NULL) {
      Block.group = new KaxBlockGroup();
    }
  }
#if MATROSKA_VERSION >= 2
  else {

    if (Block.simpleblock != NULL) {
      KaxSimpleBlock *old_simpleblock = Block.simpleblock;
      Block.group = new KaxBlockGroup();
      // _TODO_ : move all the data to the blockgroup
      assert(false);
      // -> while(frame) AddFrame(myBuffer)
      delete old_simpleblock;
    } else {
      Block.group = new KaxBlockGroup();
    }
  }
#endif
  if (ParentCluster != NULL)
    Block.group->SetParent(*ParentCluster);

  bUseSimpleBlock = false;
  return true;
}

void KaxBlockBlob::SetBlockGroup( KaxBlockGroup &BlockRef )
{
  assert(!bUseSimpleBlock);
  Block.group = &BlockRef;
}

filepos_t KaxBlockVirtual::ReadData(IOCallback & input, ScopeMode /* ReadFully */)
{
  input.setFilePointer(SizePosition + CodedSizeLength(Size, SizeLength, bSizeIsFinite) + Size, seek_beginning);
  return GetSize();
}

END_LIBMATROSKA_NAMESPACE