           args.has_page_sizes = parse_bool(on);
           break;
         } else if (param.long_flag == "chunk_size") {
-          args.chunk_size = std::stol(*(argv++));
+          args.chunk_size = size_t(std::stoull(*(argv++)));
           break;
         } else {
           std::cerr << "INTERNAL ERROR: Unhandled paramter '" << arg << "'." << std::endl;

  }

  const size_t num_chunks = split_data.size();
  for (int d = 0; d < num_duplicates; ++d) {
    split_data.insert(split_data.end(), split_data.begin(),
        split_data.begin()+num_chunks);
  }

  size_t compressed_size = 0;
  double comp_time = 0.0;
  double decomp_time = 0.0;
  for (size_t iter = 0; iter < count; ++iter) {
    // compression
    nvcompStatus_t status;

