Function gen_compressible_buffer

lib/cpp/test/ZlibTest.cpp:99–129

}

boost::shared_array<uint8_t> gen_compressible_buffer(uint32_t buf_len) {
  auto* buf = new uint8_t[buf_len];

  // Generate small runs of alternately increasing and decreasing bytes
  boost::uniform_smallint<uint32_t> run_length_distribution(1, 64);
  boost::uniform_smallint<uint8_t> byte_distribution(0, UINT8_MAX);
  boost::variate_generator<boost::mt19937, boost::uniform_smallint<uint8_t> >
      byte_generator(rng, byte_distribution);
  boost::variate_generator<boost::mt19937, boost::uniform_smallint<uint32_t> >
      run_len_generator(rng, run_length_distribution);

  uint32_t idx = 0;
  int8_t step = 1;
  while (idx < buf_len) {
    uint32_t run_length = run_len_generator();
    if (idx + run_length > buf_len) {
      run_length = buf_len - idx;
    }

    uint8_t byte = byte_generator();
    for (uint32_t n = 0; n < run_length; ++n) {
      buf[idx] = byte;
      ++idx;
      byte += step;
    }

    step *= -1;
  }

  return boost::shared_array<uint8_t>(buf);
}

boost::shared_array<uint8_t> gen_random_buffer(uint32_t buf_len) {
  auto* buf = new uint8_t[buf_len];