next_prior_test.cpp 4.1 KB

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  1. // Boost test program for next() and prior() utilities.
  2. // Copyright 2003 Daniel Walker. Use, modification, and distribution
  3. // are subject to the Boost Software License, Version 1.0. (See
  4. // accompanying file LICENSE_1_0.txt or a copy at
  5. // http://www.boost.org/LICENSE_1_0.txt.)
  6. // See http://www.boost.org/libs/utility for documentation.
  7. // Revision History 13 Dec 2003 Initial Version (Daniel Walker)
  8. // next() and prior() are replacements for operator+ and operator- for
  9. // non-random-access iterators. The semantics of these operators are
  10. // such that after executing j = i + n, std::distance(i, j) equals
  11. // n. Tests are provided to ensure next() has the same
  12. // result. Parallel tests are provided for prior(). The tests call
  13. // next() and prior() several times. next() and prior() are very
  14. // simple functions, though, and it would be very strange if these
  15. // tests were to fail.
  16. #include <boost/core/lightweight_test.hpp>
  17. #include <list>
  18. #include <vector>
  19. #include <boost/next_prior.hpp>
  20. template<class RandomAccessIterator, class ForwardIterator>
  21. bool plus_one_test(RandomAccessIterator first, RandomAccessIterator last, ForwardIterator first2)
  22. {
  23. RandomAccessIterator i = first;
  24. ForwardIterator j = first2;
  25. while(i != last)
  26. i = i + 1, j = boost::next(j);
  27. return std::distance(first, i) == std::distance(first2, j);
  28. }
  29. template<class RandomAccessIterator, class ForwardIterator>
  30. bool plus_n_test(RandomAccessIterator first, RandomAccessIterator last, ForwardIterator first2)
  31. {
  32. RandomAccessIterator i = first;
  33. ForwardIterator j = first2;
  34. for(int n = 0; i != last; ++n)
  35. i = first + n, j = boost::next(first2, n);
  36. return std::distance(first, i) == std::distance(first2, j);
  37. }
  38. template<class RandomAccessIterator, class BidirectionalIterator>
  39. bool minus_one_test(RandomAccessIterator first, RandomAccessIterator last, BidirectionalIterator last2)
  40. {
  41. RandomAccessIterator i = last;
  42. BidirectionalIterator j = last2;
  43. while(i != first)
  44. i = i - 1, j = boost::prior(j);
  45. return std::distance(i, last) == std::distance(j, last2);
  46. }
  47. template<class RandomAccessIterator, class BidirectionalIterator>
  48. bool minus_n_test(RandomAccessIterator first, RandomAccessIterator last, BidirectionalIterator last2)
  49. {
  50. RandomAccessIterator i = last;
  51. BidirectionalIterator j = last2;
  52. for(int n = 0; i != first; ++n)
  53. i = last - n, j = boost::prior(last2, n);
  54. return std::distance(i, last) == std::distance(j, last2);
  55. }
  56. template<class Iterator, class Distance>
  57. bool minus_n_unsigned_test(Iterator first, Iterator last, Distance size)
  58. {
  59. Iterator i = boost::prior(last, size);
  60. return i == first;
  61. }
  62. int main(int, char*[])
  63. {
  64. std::vector<int> x(8);
  65. std::list<int> y(x.begin(), x.end());
  66. // Tests with iterators
  67. BOOST_TEST(plus_one_test(x.begin(), x.end(), y.begin()));
  68. BOOST_TEST(plus_n_test(x.begin(), x.end(), y.begin()));
  69. BOOST_TEST(minus_one_test(x.begin(), x.end(), y.end()));
  70. BOOST_TEST(minus_n_test(x.begin(), x.end(), y.end()));
  71. BOOST_TEST(minus_n_unsigned_test(x.begin(), x.end(), x.size()));
  72. BOOST_TEST(minus_n_unsigned_test(y.begin(), y.end(), y.size()));
  73. BOOST_TEST(plus_one_test(x.rbegin(), x.rend(), y.begin()));
  74. BOOST_TEST(plus_n_test(x.rbegin(), x.rend(), y.begin()));
  75. BOOST_TEST(minus_one_test(x.rbegin(), x.rend(), y.end()));
  76. BOOST_TEST(minus_n_test(x.rbegin(), x.rend(), y.end()));
  77. BOOST_TEST(minus_n_unsigned_test(x.rbegin(), x.rend(), x.size()));
  78. BOOST_TEST(minus_n_unsigned_test(x.rbegin(), x.rend(), y.size()));
  79. // Test with pointers
  80. std::vector<int> z(x.size());
  81. int* p = &z[0];
  82. BOOST_TEST(plus_one_test(x.begin(), x.end(), p));
  83. BOOST_TEST(plus_n_test(x.begin(), x.end(), p));
  84. BOOST_TEST(minus_one_test(x.begin(), x.end(), p + z.size()));
  85. BOOST_TEST(minus_n_test(x.begin(), x.end(), p + z.size()));
  86. BOOST_TEST(minus_n_unsigned_test(p, p + z.size(), z.size()));
  87. // Tests with integers
  88. BOOST_TEST(boost::next(5) == 6);
  89. BOOST_TEST(boost::next(5, 7) == 12);
  90. BOOST_TEST(boost::prior(5) == 4);
  91. BOOST_TEST(boost::prior(5, 7) == -2);
  92. BOOST_TEST(boost::prior(5, 7u) == -2);
  93. return boost::report_errors();
  94. }