Function ExtractDataURI

IO/Core/vtkURILoader.cxx:231–299

Helper to extract data URI header

// Helper to extract data URI header
DataURIInfo ExtractDataURI(const char* begin, const char* end)
{
  DataURIInfo output{};

  if (begin == end)
  {
    vtkErrorWithObjectMacro(nullptr, "Empty data URI");
    return output;
  }

  const auto typeEnd = std::find_if(begin, end, [](char c) { return c == ';' || c == ','; });

  if (typeEnd == end)
  {
    vtkErrorWithObjectMacro(nullptr, "No ',' in data URI");
    return output;
  }

  if (begin != typeEnd) // type specified
  {
    auto type = std::string{ begin, typeEnd };
    begin = typeEnd;

    output.Type = std::move(type);
  }
  else
  {
    output.Type = "text/plain;charset=US-ASCII";
  }

  while (*begin == ';')
  {
    ++begin; // discard ;
    const auto paramEnd = std::find_if(begin, end, [](char c) { return c == ';' || c == ','; });

    if (paramEnd == end)
    {
      vtkErrorWithObjectMacro(nullptr, "Truncated data URI header");
      return output;
    }

    if (*paramEnd == ',')
    {
      auto param = std::string{ begin, paramEnd };
      if (param == "base64")
      {
        output.base64 = true;
      }

      // Parameters aren't stored since unused, but if needed its where it should be done
      begin = paramEnd;
      break;
    }

    // Parameters aren't stored since unused, but if needed its where it should be done
    begin = paramEnd;
  }