libstdc++-v3/testsuite/performance/27_io/ifstream_extract_float.cc

   1 // Copyright (C) 2004-2019 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 #include <unistd.h>
  19 #include <fstream>
  20 #include <sstream>
  21 #include <testsuite_performance.h>
  22
  23 void test_extraction(int p = 6)
  24 {
  25   using namespace std;
  26   using namespace __gnu_test;
  27
  28   const char* filename = "tmp_perf_float.txt";
  29   const int iterations = 10000000;
  30
  31   ostringstream oss;
  32   oss << "precision " << p;
  33
  34   // Construct data.
  35   {
  36     ofstream out(filename);
  37     out.precision(p);
  38     for (int i = 0; i < iterations; ++i)
  39       {
  40         float f = i * 3.14159265358979323846;
  41         out << f << '\n';
  42       }
  43   }
  44
  45   {
  46     time_counter time;
  47     resource_counter resource;
  48
  49     ifstream in(filename);
  50     in.precision(p);
  51     float f;
  52     start_counters(time, resource);
  53     for (int j, i = 0; i < iterations; ++i)
  54       in >> f;
  55     stop_counters(time, resource);
  56     report_performance(__FILE__, oss.str(), time, resource);
  57   }
  58
  59   unlink(filename);
  60 };
  61
  62 int main()
  63 {
  64   test_extraction(6);
  65   test_extraction(12);
  66   return 0;
  67 }