libstdc++-v3/include/parallel/checkers.h

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2007, 2008 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
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   8 // Foundation; either version 2, or (at your option) any later
   9 // version.
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  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
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  21 // As a special exception, you may use this file as part of a free
  22 // software library without restriction.  Specifically, if other files
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  29 // Public License.
  30
  31 /** @file parallel/checkers.h
  32  *  @brief Routines for checking the correctness of algorithm results.
  33  *  This file is a GNU parallel extension to the Standard C++ Library.
  34  */
  35
  36 // Written by Johannes Singler.
  37
  38 #ifndef _GLIBCXX_PARALLEL_CHECKERS
  39 #define _GLIBCXX_PARALLEL_CHECKERS 1
  40
  41 #include <functional>
  42 #include <cstdio>
  43 #include <bits/stl_algobase.h>
  44
  45 namespace __gnu_parallel
  46 {
  47   /**
  48    * @brief Check whether @c [begin, @c end) is sorted according to @c comp.
  49    * @param begin Begin iterator of sequence.
  50    * @param end End iterator of sequence.
  51    * @param comp Comparator.
  52    * @return @c true if sorted, @c false otherwise.
  53    */
  54   // XXX Comparator default template argument
  55   template<typename InputIterator, typename Comparator>
  56     bool
  57     is_sorted(InputIterator begin, InputIterator end,
  58               Comparator comp
  59               = std::less<typename std::iterator_traits<InputIterator>::
  60               value_type>())
  61     {
  62       if (begin == end)
  63         return true;
  64
  65       InputIterator current(begin), recent(begin);
  66
  67       unsigned long long position = 1;
  68       for (current++; current != end; current++)
  69         {
  70           if (comp(*current, *recent))
  71             {
  72               printf("is_sorted: check failed before position %i.\n",
  73                      position);
  74               return false;
  75             }
  76           recent = current;
  77           position++;
  78         }
  79
  80       return true;
  81     }
  82
  83   /**
  84    * @brief Check whether @c [begin, @c end) is sorted according to @c comp.
  85    * Prints the position in case an unordered pair is found.
  86    * @param begin Begin iterator of sequence.
  87    * @param end End iterator of sequence.
  88    * @param first_failure The first failure is returned in this variable.
  89    * @param comp Comparator.
  90    * @return @c true if sorted, @c false otherwise.
  91    */
  92   // XXX Comparator default template argument
  93   template<typename InputIterator, typename Comparator>
  94     bool
  95     is_sorted_failure(InputIterator begin, InputIterator end,
  96                       InputIterator& first_failure,
  97                       Comparator comp
  98                       = std::less<typename std::iterator_traits<InputIterator>::
  99                       value_type>())
 100     {
 101       if (begin == end)
 102         return true;
 103
 104       InputIterator current(begin), recent(begin);
 105
 106       unsigned long long position = 1;
 107       for (current++; current != end; current++)
 108         {
 109           if (comp(*current, *recent))
 110             {
 111               first_failure = current;
 112               printf("is_sorted: check failed before position %lld.\n",
 113                      position);
 114               return false;
 115             }
 116           recent = current;
 117           position++;
 118         }
 119
 120       first_failure = end;
 121       return true;
 122     }
 123
 124   /**
 125    * @brief Check whether @c [begin, @c end) is sorted according to @c comp.
 126    * Prints all unordered pair, including the surrounding two elements.
 127    * @param begin Begin iterator of sequence.
 128    * @param end End iterator of sequence.
 129    * @param comp Comparator.
 130    * @return @c true if sorted, @c false otherwise.
 131    */
 132   template<typename InputIterator, typename Comparator>
 133     bool
 134     // XXX Comparator default template argument
 135     is_sorted_print_failures(InputIterator begin, InputIterator end,
 136                              Comparator comp
 137                              = std::less<typename std::iterator_traits
 138                              <InputIterator>::value_type>())
 139     {
 140       if (begin == end)
 141         return true;
 142
 143       InputIterator recent(begin);
 144       bool ok = true;
 145
 146       for (InputIterator pos(begin + 1); pos != end; pos++)
 147         {
 148           if (comp(*pos, *recent))
 149             {
 150               printf("%ld: %d %d %d %d\n", pos - begin, *(pos - 2),
 151                      *(pos- 1), *pos, *(pos + 1));
 152               ok = false;
 153             }
 154           recent = pos;
 155         }
 156       return ok;
 157     }
 158 }
 159
 160 #endif