1 | /* |
---|---|

2 | Copyright (c) Marshall Clow 2008-2012. |

3 | |

4 | Distributed under the Boost Software License, Version 1.0. (See accompanying |

5 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |

6 | */ |

7 | |

8 | /// \file one_of.hpp |

9 | /// \brief Test ranges to see if only one element matches a value or predicate. |

10 | /// \author Marshall Clow |

11 | |

12 | #ifndef BOOST_ALGORITHM_ONE_OF_HPP |

13 | #define BOOST_ALGORITHM_ONE_OF_HPP |

14 | |

15 | #include <algorithm> // for std::find and std::find_if |

16 | #include <boost/algorithm/cxx11/none_of.hpp> |

17 | |

18 | #include <boost/range/begin.hpp> |

19 | #include <boost/range/end.hpp> |

20 | |

21 | namespace boost { namespace algorithm { |

22 | |

23 | /// \fn one_of ( InputIterator first, InputIterator last, Predicate p ) |

24 | /// \return true if the predicate 'p' is true for exactly one item in [first, last). |

25 | /// |

26 | /// \param first The start of the input sequence |

27 | /// \param last One past the end of the input sequence |

28 | /// \param p A predicate for testing the elements of the sequence |

29 | /// |

30 | template<typename InputIterator, typename Predicate> |

31 | bool one_of ( InputIterator first, InputIterator last, Predicate p ) |

32 | { |

33 | InputIterator i = std::find_if (first, last, p); |

34 | if (i == last) |

35 | return false; // Didn't occur at all |

36 | return boost::algorithm::none_of (++i, last, p); |

37 | } |

38 | |

39 | /// \fn one_of ( const Range &r, Predicate p ) |

40 | /// \return true if the predicate 'p' is true for exactly one item in the range. |

41 | /// |

42 | /// \param r The input range |

43 | /// \param p A predicate for testing the elements of the range |

44 | /// |

45 | template<typename Range, typename Predicate> |

46 | bool one_of ( const Range &r, Predicate p ) |

47 | { |

48 | return boost::algorithm::one_of ( boost::begin (r), boost::end (r), p ); |

49 | } |

50 | |

51 | |

52 | /// \fn one_of_equal ( InputIterator first, InputIterator last, const V &val ) |

53 | /// \return true if the value 'val' exists only once in [first, last). |

54 | /// |

55 | /// \param first The start of the input sequence |

56 | /// \param last One past the end of the input sequence |

57 | /// \param val A value to compare against |

58 | /// |

59 | template<typename InputIterator, typename V> |

60 | bool one_of_equal ( InputIterator first, InputIterator last, const V &val ) |

61 | { |

62 | InputIterator i = std::find (first, last, val); // find first occurrence of 'val' |

63 | if (i == last) |

64 | return false; // Didn't occur at all |

65 | return boost::algorithm::none_of_equal (++i, last, val); |

66 | } |

67 | |

68 | /// \fn one_of_equal ( const Range &r, const V &val ) |

69 | /// \return true if the value 'val' exists only once in the range. |

70 | /// |

71 | /// \param r The input range |

72 | /// \param val A value to compare against |

73 | /// |

74 | template<typename Range, typename V> |

75 | bool one_of_equal ( const Range &r, const V &val ) |

76 | { |

77 | return boost::algorithm::one_of_equal ( boost::begin (r), boost::end (r), val ); |

78 | } |

79 | |

80 | }} // namespace boost and algorithm |

81 | |

82 | #endif // BOOST_ALGORITHM_ALL_HPP |

83 |