Function vtkXMLWriterWriteBinaryDataBlocks

IO/XML/vtkXMLWriter.cxx:337–422

------------------------------------------------------------------------------ Specialize for string arrays:

//------------------------------------------------------------------------------
// Specialize for string arrays:
int vtkXMLWriterWriteBinaryDataBlocks(vtkXMLWriter* writer,
  vtkArrayIteratorTemplate<vtkStdString>* iter, int wordType, size_t outWordSize, size_t numStrings,
  int)
{
  vtkXMLWriterHelper::SetProgressPartial(writer, 0);
  vtkStdString::value_type* allocated_buffer = nullptr;
  vtkStdString::value_type* temp_buffer = nullptr;
  if (vtkXMLWriterHelper::GetInt32IdTypeBuffer(writer))
  {
    temp_buffer =
      reinterpret_cast<vtkStdString::value_type*>(vtkXMLWriterHelper::GetInt32IdTypeBuffer(writer));
  }
  else if (vtkXMLWriterHelper::GetByteSwapBuffer(writer))
  {
    temp_buffer =
      reinterpret_cast<vtkStdString::value_type*>(vtkXMLWriterHelper::GetByteSwapBuffer(writer));
  }
  else
  {
    allocated_buffer = new vtkStdString::value_type[writer->GetBlockSize() / outWordSize];
    temp_buffer = allocated_buffer;
  }

  // For string arrays, writing as binary requires that the strings are written
  // out into a contiguous block. This is essential since the compressor can
  // only compress complete blocks of data.
  size_t maxCharsPerBlock = writer->GetBlockSize() / outWordSize;

  size_t index = 0; // index in string array.
  int result = 1;
  vtkIdType stringOffset = 0; // num of chars of string written in previous block.
                              // this is required since a string may not fit completely in a block.

  while (result && index < numStrings) // write one block at a time.
  {
    size_t cur_offset = 0; // offset into the temp_buffer.
    while (index < numStrings && cur_offset < maxCharsPerBlock)
    {
      vtkStdString& str = iter->GetValue(static_cast<vtkIdType>(index));
      vtkStdString::size_type length = str.size();
      const char* data = str.c_str();
      data += stringOffset; // advance by the chars already written.
      length -= stringOffset;
      if (length == 0)
      {
        // just write the string termination char.
        temp_buffer[cur_offset++] = 0x0;
        stringOffset = 0;
        index++; // advance to the next string
      }
      else
      {
        size_t new_offset = cur_offset + length + 1; // (+1) for termination char.
        if (new_offset <= maxCharsPerBlock)
        {
          memcpy(&temp_buffer[cur_offset], data, length);
          cur_offset += length;
          temp_buffer[cur_offset++] = 0x0;