ceph/src/boost/libs/sort/example/rightshiftsample.cpp

   1 //! \brief Integer sort with a rightshift functor sorting example.
   2 //! \file
   3 //
   4 //  Copyright Steven Ross 2009-2014.
   5 //
   6 // Distributed under the Boost Software License, Version 1.0.
   7 //    (See accompanying file LICENSE_1_0.txt or copy at
   8 //          http://www.boost.org/LICENSE_1_0.txt)
   9
  10 //  See http://www.boost.org/libs/sort for library home page.
  11
  12 // Caution: this file contains Quickbook markup as well as code
  13 // and comments, don't change any of the special comment markups!
  14
  15 #include <boost/sort/spreadsort/spreadsort.hpp>
  16 #include <time.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <algorithm>
  20 #include <vector>
  21 #include <string>
  22 #include <fstream>
  23 #include <iostream>
  24 using namespace boost::sort::spreadsort;
  25
  26 #define DATA_TYPE int
  27
  28 //[rightshift_int_functor
  29 struct rightshift {
  30   inline int operator()(DATA_TYPE x, unsigned offset) { return x >> offset; }
  31 };
  32 //] [/rightshift_int_functor]
  33
  34 //Pass in an argument to test std::sort
  35 int main(int argc, const char ** argv) {
  36   size_t uCount,uSize=sizeof(DATA_TYPE);
  37   bool stdSort = false;
  38   unsigned loopCount = 1;
  39   for (int u = 1; u < argc; ++u) {
  40     if (std::string(argv[u]) == "-std")
  41       stdSort = true;
  42     else
  43       loopCount = atoi(argv[u]);
  44   }
  45   std::ifstream input("input.txt", std::ios_base::in | std::ios_base::binary);
  46   if (input.fail()) {
  47     printf("input.txt could not be opened\n");
  48     return 1;
  49   }
  50   double total = 0.0;
  51   std::vector<DATA_TYPE> array;
  52   input.seekg (0, std::ios_base::end);
  53     size_t length = input.tellg();
  54   uCount = length/uSize;
  55   //Run multiple loops, if requested
  56   for (unsigned u = 0; u < loopCount; ++u) {
  57     input.seekg (0, std::ios_base::beg);
  58     //Conversion to a vector
  59     array.resize(uCount);
  60     unsigned v = 0;
  61     while (input.good() && v < uCount)
  62       input.read(reinterpret_cast<char *>(&(array[v++])), uSize );
  63     if (v < uCount)
  64       array.resize(v);
  65     clock_t start, end;
  66     double elapsed;
  67     start = clock();
  68     if (stdSort) {
  69       std::sort(array.begin(), array.end());
  70     } else {
  71 //[rightshift_1
  72       integer_sort(array.begin(), array.end(), rightshift());
  73 //] [/rightshift_1]
  74     }
  75     end = clock();
  76     elapsed = static_cast<double>(end - start) ;
  77     std::ofstream ofile;
  78     if (stdSort)
  79       ofile.open("standard_sort_out.txt", std::ios_base::out |
  80                  std::ios_base::binary | std::ios_base::trunc);
  81     else
  82       ofile.open("boost_sort_out.txt", std::ios_base::out |
  83                  std::ios_base::binary | std::ios_base::trunc);
  84     if (ofile.good()) {
  85       for (unsigned v = 0; v < array.size(); ++v) {
  86         ofile.write(reinterpret_cast<char *>(&(array[v])), sizeof(array[v]) );
  87       }
  88       ofile.close();
  89     }
  90     total += elapsed;
  91     array.clear();
  92   }
  93   if (stdSort)
  94     printf("std::sort elapsed time %f\n", total / CLOCKS_PER_SEC);
  95   else
  96     printf("spreadsort elapsed time %f\n", total / CLOCKS_PER_SEC);
  97   return 0;
  98 }