stringstream_vs_string.cc

#include <iterator>
#include <iostream>
#include <sstream>
#include <string>
#include <string.h>
#include <memory>
#include <sys/time.h>

const int maxChunkSize = 32000;

int readopt(char **argv, const char *what, int pos) {
  int result;
  if (argv[pos]) {
    std::cout << what << ": ";
    result = atoi(argv[pos]);
    std::cout << result << std::endl;
    return result;
  }
  else {
    std::cout << "Provide '" << what << "' as parameter in position " << pos << std::endl;
    exit(1);
  }

  return result;
}

int main(int argc, char **argv) {
  std::cout << std::endl;
  int iterations = readopt(argv, "Iterations", 1);
  int appends = readopt(argv, "Append operations", 2);
  std::string what = std::string("Chunk appended size (max ");
  what += std::to_string(maxChunkSize);
  what += (")");
  int chunkSize = readopt(argv, what.c_str(), 3);
  if (chunkSize > maxChunkSize) { chunkSize = maxChunkSize; std::cout << "Chunks size fixed to: " << maxChunkSize << std::endl; }

  char data[maxChunkSize];
  memset(data, 'x', chunkSize);

  std::shared_ptr<std::stringstream> body_ss;
  std::shared_ptr<std::string> body_str;
  std::cout << std::endl;

  struct timeval t1, t2, t3;

  gettimeofday(&t1, NULL);

  for(int k=0; k < iterations; k++) {
    {
      auto body_str = std::make_shared<std::string>();
      for (int j=0; j < appends; j++) body_str->append(data, chunkSize);
    }
  }

  gettimeofday(&t2, NULL);

  for(int k=0; k < iterations; k++) {
    {
      auto body_ss = std::make_shared<std::stringstream>();
      for (int j=0; j < appends; j++) std::copy(data, data + chunkSize, std::ostream_iterator<std::uint8_t>(*body_ss));
    }
  }

  gettimeofday(&t3, NULL);

  std::uint64_t delta1 = (t2.tv_sec*1000000 + t2.tv_usec) - (t1.tv_sec*1000000 + t1.tv_usec);
  std::uint64_t delta2 = (t3.tv_sec*1000000 + t3.tv_usec) - (t2.tv_sec*1000000 + t2.tv_usec);
  std::cout << "TOTAL COST" << std::endl << std::endl;
  std::cout << "std::string        " << delta1 << " usecs" << std::endl;
  std::cout << "std::stringstream: " << delta2 << " usecs" << std::endl;

  return 0;
}