1// -*- C++ -*-
2
3// Copyright (C) 2007, 2008, 2009 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 3, 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// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file parallel/checkers.h
26 *  @brief Routines for checking the correctness of algorithm results.
27 *  This file is a GNU parallel extension to the Standard C++ Library.
28 */
29
30// Written by Johannes Singler.
31
32#ifndef _GLIBCXX_PARALLEL_CHECKERS_H
33#define _GLIBCXX_PARALLEL_CHECKERS_H 1
34
35#include <functional>
36#include <cstdio>
37#include <bits/stl_algobase.h>
38
39namespace __gnu_parallel
40{
41  /**
42   * @brief Check whether @c [begin, @c end) is sorted according to @c comp.
43   * @param begin Begin iterator of sequence.
44   * @param end End iterator of sequence.
45   * @param comp Comparator.
46   * @return @c true if sorted, @c false otherwise.
47   */
48  // XXX Comparator default template argument
49  template<typename InputIterator, typename Comparator>
50    bool
51    is_sorted(InputIterator begin, InputIterator end,
52	      Comparator comp
53	      = std::less<typename std::iterator_traits<InputIterator>::
54	      value_type>())
55    {
56      if (begin == end)
57	return true;
58
59      InputIterator current(begin), recent(begin);
60
61      unsigned long long position = 1;
62      for (current++; current != end; current++)
63	{
64	  if (comp(*current, *recent))
65	    {
66	      printf("is_sorted: check failed before position %i.\n",
67		     position);
68	      return false;
69	    }
70	  recent = current;
71	  position++;
72	}
73
74      return true;
75    }
76
77  /**
78   * @brief Check whether @c [begin, @c end) is sorted according to @c comp.
79   * Prints the position in case an unordered pair is found.
80   * @param begin Begin iterator of sequence.
81   * @param end End iterator of sequence.
82   * @param first_failure The first failure is returned in this variable.
83   * @param comp Comparator.
84   * @return @c true if sorted, @c false otherwise.
85   */
86  // XXX Comparator default template argument
87  template<typename InputIterator, typename Comparator>
88    bool
89    is_sorted_failure(InputIterator begin, InputIterator end,
90		      InputIterator& first_failure,
91		      Comparator comp
92		      = std::less<typename std::iterator_traits<InputIterator>::
93		      value_type>())
94    {
95      if (begin == end)
96	return true;
97
98      InputIterator current(begin), recent(begin);
99
100      unsigned long long position = 1;
101      for (current++; current != end; current++)
102	{
103	  if (comp(*current, *recent))
104	    {
105	      first_failure = current;
106	      printf("is_sorted: check failed before position %lld.\n",
107		     position);
108	      return false;
109	    }
110	  recent = current;
111	  position++;
112	}
113
114      first_failure = end;
115      return true;
116    }
117
118  /**
119   * @brief Check whether @c [begin, @c end) is sorted according to @c comp.
120   * Prints all unordered pair, including the surrounding two elements.
121   * @param begin Begin iterator of sequence.
122   * @param end End iterator of sequence.
123   * @param comp Comparator.
124   * @return @c true if sorted, @c false otherwise.
125   */
126  template<typename InputIterator, typename Comparator>
127    bool
128    // XXX Comparator default template argument
129    is_sorted_print_failures(InputIterator begin, InputIterator end,
130			     Comparator comp
131			     = std::less<typename std::iterator_traits
132			     <InputIterator>::value_type>())
133    {
134      if (begin == end)
135	return true;
136
137      InputIterator recent(begin);
138      bool ok = true;
139
140      for (InputIterator pos(begin + 1); pos != end; pos++)
141	{
142	  if (comp(*pos, *recent))
143	    {
144	      printf("%ld: %d %d %d %d\n", pos - begin, *(pos - 2),
145		     *(pos- 1), *pos, *(pos + 1));
146	      ok = false;
147	    }
148	  recent = pos;
149	}
150      return ok;
151    }
152}
153
154#endif /* _GLIBCXX_PARALLEL_CHECKERS_H */
155