ceph/src/boost/libs/spirit/workbench/karma/real_generator.cpp

   1 //  Copyright (c) 2001-2010 Hartmut Kaiser
   2 //
   3 //  Distributed under the Boost Software License, Version 1.0. (See accompanying
   4 //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #include <climits>
   7 #include <cassert>
   8
   9 #include <iostream>
  10 #include <sstream>
  11 #include <boost/format.hpp>
  12
  13 #include <boost/spirit/include/karma.hpp>
  14
  15 #include "../high_resolution_timer.hpp"
  16
  17 using namespace std;
  18 using namespace boost::spirit;
  19
  20 #define MAX_ITERATION 10000000
  21
  22 ///////////////////////////////////////////////////////////////////////////////
  23 struct random_fill
  24 {
  25     double operator()() const
  26     {
  27         double scale = std::rand() / 100 + 1;
  28         return double(std::rand() * std::rand()) / scale;
  29     }
  30 };
  31
  32 ///////////////////////////////////////////////////////////////////////////////
  33 int main()
  34 {
  35     namespace karma = boost::spirit::karma;
  36     char buffer[512]; // we don't expect more than 512 bytes to be generated
  37
  38     cout << "Converting " << MAX_ITERATION
  39          << " randomly generated double values to strings." << flush << endl;
  40
  41     std::srand(0);
  42     std::vector<double> v (MAX_ITERATION);
  43     std::generate(v.begin(), v.end(), random_fill()); // randomly fill the vector
  44
  45     // test the C libraries gcvt function (the most low level function for
  46     // string conversion available)
  47     {
  48         std::string str;
  49         util::high_resolution_timer t;
  50
  51         for (int i = 0; i < MAX_ITERATION; ++i)
  52         {
  53             gcvt(v[i], 10, buffer);
  54             str = buffer;      // compensate for string ops in other benchmarks
  55         }
  56
  57         cout << "gcvt:    " << t.elapsed() << " [s]" << flush << endl;
  58     }
  59
  60     // test the iostreams library
  61     {
  62         std::stringstream str;
  63         util::high_resolution_timer t;
  64
  65         for (int i = 0; i < MAX_ITERATION; ++i)
  66         {
  67             str.str("");
  68             str << v[i];
  69         }
  70
  71         cout << "iostreams: " << t.elapsed() << " [s]" << flush << endl;
  72     }
  73
  74     // test the Boost.Format library
  75     {
  76         std::string str;
  77         boost::format double_format("%f");
  78         util::high_resolution_timer t;
  79
  80         for (int i = 0; i < MAX_ITERATION; ++i)
  81         {
  82             str = boost::str(double_format % v[i]);
  83         }
  84
  85         cout << "Boost.Format: " << t.elapsed() << " [s]" << flush << endl;
  86     }
  87
  88     // test the Karma double_ generation routines
  89     {
  90         std::string str;
  91         util::high_resolution_timer t;
  92
  93         for (int i = 0; i < MAX_ITERATION; ++i)
  94         {
  95             char *ptr = buffer;
  96             karma::generate(ptr, double_, v[i]);
  97             *ptr = '\0';
  98             str = buffer;      // compensate for string ops in other benchmarks
  99         }
 100
 101         cout << "double_: " << t.elapsed() << " [s]" << flush << endl;
 102     }
 103
 104     return 0;
 105 }
 106