long Chapters::Atom::Parse(IMkvReader* pReader, long long pos, long long size) {
 const long long stop = pos + size;

 while (pos < stop) {
 long long id, size;

 long status = ParseElementHeader(pReader, pos, stop, id, size);

 if (status < 0) // error
 return status;

 if (size == 0) // weird
 continue;

 if (id == 0x00) { // Display ID
      status = ParseDisplay(pReader, pos, size);

 if (status < 0) // error
 return status;
 } else if (id == 0x1654) { // StringUID ID
      status = UnserializeString(pReader, pos, size, m_string_uid);

 if (status < 0) // error
 return status;
 } else if (id == 0x33C4) { // UID ID
 long long val;
      status = UnserializeInt(pReader, pos, size, val);

 if (status < 0) // error
 return status;

      m_uid = static_cast<unsigned long long>(val);
 } else if (id == 0x11) { // TimeStart ID
 const long long val = UnserializeUInt(pReader, pos, size);

 if (val < 0) // error
 return static_cast<long>(val);

      m_start_timecode = val;
 } else if (id == 0x12) { // TimeEnd ID
 const long long val = UnserializeUInt(pReader, pos, size);

 if (val < 0) // error
 return static_cast<long>(val);

      m_stop_timecode = val;
 }

    pos += size;
 if (pos > stop)
 return E_FILE_FORMAT_INVALID;
 }

 if (pos != stop)
 return E_FILE_FORMAT_INVALID;
 return 0;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.