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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2007 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the terms
   7 // of the GNU General Public License as published by the Free Software
   8 // Foundation; either version 2, or (at your option) any later
   9 // version.
  10
  11 // This library is distributed in the hope that it will be useful, but
  12 // WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING.  If not, write to
  18 // the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  19 // MA 02111-1307, USA.
  20
  21 // As a special exception, you may use this file as part of a free
  22 // software library without restriction.  Specifically, if other files
  23 // instantiate templates or use macros or inline functions from this
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  25 // produce an executable, this file does not by itself cause the
  26 // resulting executable to be covered by the GNU General Public
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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, Comparator comp = std::less<typename std::iterator_traits<InputIterator>::value_type>())
  58   {
  59     if (begin == end)
  60       return true;
  61
  62     InputIterator current(begin), recent(begin);
  63
  64     unsigned long long position = 1;
  65     for (current++; current != end; current++)
  66       {
  67         if (comp(*current, *recent))
  68           {
  69             printf("is_sorted: check failed before position %i.\n", position);
  70             return false;
  71           }
  72         recent = current;
  73         position++;
  74       }
  75
  76     return true;
  77   }
  78
  79   /**
  80    * @brief Check whether @c [begin, @c end) is sorted according to @c comp.
  81    * Prints the position in case an misordered pair is found.
  82    * @param begin Begin iterator of sequence.
  83    * @param end End iterator of sequence.
  84    * @param first_failure The first failure is returned in this variable.
  85    * @param comp Comparator.
  86    * @return @c true if sorted, @c false otherwise.
  87    */
  88   // XXX Comparator default template argument
  89   template<typename InputIterator, typename Comparator>
  90   bool
  91   is_sorted_failure(InputIterator begin, InputIterator end, InputIterator& first_failure, Comparator comp = std::less<typename std::iterator_traits<InputIterator>::value_type>())
  92   {
  93     if (begin == end)
  94       return true;
  95
  96     InputIterator current(begin), recent(begin);
  97
  98     unsigned long long position = 1;
  99     for (current++; current != end; current++)
 100       {
 101         if (comp(*current, *recent))
 102           {
 103             first_failure = current;
 104             printf("is_sorted: check failed before position %lld.\n", position);
 105             return false;
 106           }
 107         recent = current;
 108         position++;
 109       }
 110
 111     first_failure = end;
 112     return true;
 113   }
 114
 115   /**
 116    * @brief Check whether @c [begin, @c end) is sorted according to @c comp.
 117    * Prints all misordered pair, including the surrounding two elements.
 118    * @param begin Begin iterator of sequence.
 119    * @param end End iterator of sequence.
 120    * @param comp Comparator.
 121    * @return @c true if sorted, @c false otherwise.
 122    */
 123   template<typename InputIterator, typename Comparator>
 124   bool
 125   // XXX Comparator default template argument
 126   is_sorted_print_failures(InputIterator begin, InputIterator end, Comparator comp = std::less<typename std::iterator_traits<InputIterator>::value_type>())
 127   {
 128     if (begin == end)
 129       return true;
 130
 131     InputIterator recent(begin);
 132     bool ok = true;
 133
 134     for (InputIterator pos(begin + 1); pos != end; pos++)
 135       {
 136         if (comp(*pos, *recent))
 137           {
 138             printf("%ld: %d %d %d %d\n", pos - begin, *(pos - 2),
 139                    *(pos- 1), *pos, *(pos + 1));
 140             ok = false;
 141           }
 142         recent = pos;
 143       }
 144     return ok;
 145   }
 146 }
 147
 148 #endif