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

   1 // spreadsort key and data sorting example.
   2 //
   3 //  Copyright Steven Ross 2009-2014.
   4 //
   5 // Distributed under the Boost Software License, Version 1.0.
   6 //    (See accompanying file LICENSE_1_0.txt or copy at
   7 //          http://www.boost.org/LICENSE_1_0.txt)
   8
   9 //  See http://www.boost.org/libs/sort for library home page.
  10
  11 #include <boost/sort/spreadsort/spreadsort.hpp>
  12 #include <time.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <algorithm>
  16 #include <vector>
  17 #include <string>
  18 #include <fstream>
  19 #include <sstream>
  20 #include <iostream>
  21 using namespace boost::sort::spreadsort;
  22
  23 struct DATA_TYPE {
  24     int key;
  25     std::string data;
  26     };
  27 //functor example
  28 struct lessthan {
  29   inline bool operator()(const DATA_TYPE &x, const DATA_TYPE &y) const {
  30     return x.key < y.key;
  31   }
  32 };
  33
  34 struct rightshift {
  35   inline int operator()(const DATA_TYPE &x, const unsigned offset) {
  36     return x.key >> offset;
  37   }
  38 };
  39
  40 //Pass in an argument to test std::sort
  41 int main(int argc, const char ** argv) {
  42   size_t uSize = sizeof(int);
  43   bool stdSort = false;
  44   unsigned loopCount = 1;
  45   for (int u = 1; u < argc; ++u) {
  46     if (std::string(argv[u]) == "-std")
  47       stdSort = true;
  48     else
  49       loopCount = atoi(argv[u]);
  50   }
  51   std::ifstream input("input.txt", std::ios_base::in | std::ios_base::binary);
  52   if (input.fail()) {
  53     printf("input.txt could not be opened\n");
  54     return 1;
  55   }
  56   input.seekg (0, std::ios_base::end);
  57     size_t length = input.tellg();
  58   double total = 0.0;
  59   std::vector<DATA_TYPE> array;
  60   array.reserve(length/uSize);
  61   unsigned uCount = length/uSize;
  62   //Run multiple loops, if requested
  63   for (unsigned u = 0; u < loopCount; ++u) {
  64     input.seekg (0, std::ios_base::beg);
  65     unsigned v = 0;
  66     while (input.good() && v++ < uCount) { // EOF or failure stops the reading
  67      DATA_TYPE element;
  68      input.read(reinterpret_cast<char *>(&(element.key)), sizeof(element.key));
  69      std::stringstream intstr;
  70          intstr << element.key;
  71          element.data = intstr.str();
  72          array.push_back(element);
  73     }
  74     clock_t start, end;
  75     double elapsed;
  76     start = clock();
  77     if (stdSort)
  78       std::sort(array.begin(), array.end(), lessthan());
  79     else
  80       integer_sort(array.begin(), array.end(), rightshift(), lessthan());
  81     end = clock();
  82     elapsed = static_cast<double>(end - start) ;
  83     std::ofstream ofile;
  84     if (stdSort)
  85       ofile.open("standard_sort_out.txt", std::ios_base::out |
  86                  std::ios_base::binary | std::ios_base::trunc);
  87     else
  88       ofile.open("boost_sort_out.txt", std::ios_base::out |
  89                  std::ios_base::binary | std::ios_base::trunc);
  90     if (ofile.good()) {
  91       for (unsigned v = 0; v < array.size(); ++v) {
  92         ofile.write(reinterpret_cast<char *>(&(array[v].key)),
  93                     sizeof(array[v].key));
  94         ofile << array[v].data;
  95       }
  96       ofile.close();
  97     }
  98     total += elapsed;
  99     array.clear();
 100   }
 101   input.close();
 102   if (stdSort)
 103     printf("std::sort elapsed time %f\n", total / CLOCKS_PER_SEC);
 104   else
 105     printf("spreadsort elapsed time %f\n", total / CLOCKS_PER_SEC);
 106   return 0;
 107 }