update sources to v12.2.4

[ceph.git] / ceph / src / boost / libs / sort / example / binaryalrbreaker.cpp

// a sorting example that uses the worst-case distribution for spreadsort.\r
//\r
//  Copyright Steven Ross 2009-2014.\r
//\r
// Distributed under the Boost Software License, Version 1.0.\r
//    (See accompanying file LICENSE_1_0.txt or copy at\r
//          http://www.boost.org/LICENSE_1_0.txt)\r
\r
//  See http://www.boost.org/libs/sort for library home page.\r
\r
#include <boost/sort/spreadsort/spreadsort.hpp>\r
#include <time.h>\r
#include <stdio.h>\r
#include <stdlib.h>\r
#include <algorithm>\r
#include <vector>\r
#include <string>\r
#include <fstream>\r
#include <sstream>\r
#include <iostream>\r
using namespace boost::sort::spreadsort;\r
using namespace std;\r
\r
#define DATA_TYPE boost::uint64_t\r
\r
#define ALR_THRESHOLD 3\r
\r
const unsigned max_count = ALR_THRESHOLD - 1;\r
const unsigned bit_shift = detail::rough_log_2_size(max_count) -\r
  detail::int_log_mean_bin_size;\r
const unsigned radix_threshold = detail::rough_log_2_size(max_count) + 1;\r
\r
const DATA_TYPE typed_one = 1;\r
\r
void\r
fill_vector(vector<DATA_TYPE> & input, const DATA_TYPE base_value,\r
            unsigned remaining_bits, const vector<unsigned> & indices,\r
            int index)\r
{\r
  if (index < 0) {\r
    for (unsigned u = 0; u < max_count; ++u)\r
      input.push_back((base_value << remaining_bits) +\r
                      (rand() % (1 << remaining_bits)));\r
  }\r
  else {\r
    unsigned shift = indices[index];\r
    fill_vector(input, (base_value << shift) + ((1 << shift) - 1),\r
                remaining_bits - shift, indices, index - 1);\r
    fill_vector(input, base_value << shift, remaining_bits - shift, indices,\r
                index - 1);\r
  }\r
}\r
\r
//Generates a random index from 0 up to but not including count.\r
unsigned\r
get_index(unsigned count)\r
{\r
  unsigned result = unsigned((rand() % (1 << 16))*uint64_t(count)/(1 << 16));\r
  if (result >= count)\r
    return count - 1;\r
  return result;\r
}\r
\r
//Tests std::sort vs boost::sort::spreadsort on boost::sort's worst distribution.\r
int main(int, const char **) {\r
  unsigned total_length = sizeof(DATA_TYPE) * 8;\r
  double std_sort_time = 0;\r
  double spreadsort_time = 0;\r
  for (int repetition = 0; repetition < 10; ++repetition) {\r
    vector<DATA_TYPE> input;\r
    vector<unsigned> offsets;\r
    unsigned bit_length = total_length - radix_threshold;\r
    unsigned bit_offset = bit_shift;\r
    for (; bit_length >= ++bit_offset; bit_length -= bit_offset)\r
      offsets.push_back(bit_offset);\r
    for (int ii = (1 << bit_length) - 1; ii >= 0; --ii)\r
      fill_vector(input, ii, total_length - bit_length,\r
                  offsets, offsets.size() - 1);\r
\r
    //Randomize the inputs slightly so they aren't in reverse-sorted order, for\r
    //which std::sort is very fast.\r
    for (unsigned u = 0; u < input.size() / 10; ++u)\r
      std::swap(input[get_index(input.size())], input[get_index(input.size())]);\r
\r
    //Run both std::sort and boost::sort::spreadsort.\r
    for (unsigned u = 0; u < 2; ++u) {\r
      vector<DATA_TYPE> array = input;\r
      clock_t start, end;\r
      double elapsed;\r
      start = clock();\r
      if (u)\r
        std::sort(array.begin(), array.end());\r
      else\r
        boost::sort::spreadsort::spreadsort(array.begin(), array.end());\r
      end = clock();\r
      elapsed = static_cast<double>(end - start);\r
      if (u)\r
        std_sort_time += elapsed / CLOCKS_PER_SEC;\r
      else\r
        spreadsort_time += elapsed / CLOCKS_PER_SEC;\r
      array.clear();\r
    }\r
  }\r
\r
  printf("std::sort elapsed time %f\n", std_sort_time);\r
  printf("spreadsort elapsed time %f\n", spreadsort_time);\r
  return 0;\r
}\r