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Diffstat (limited to 'boost/algorithm/cxx11/one_of.hpp')
-rw-r--r-- | boost/algorithm/cxx11/one_of.hpp | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/boost/algorithm/cxx11/one_of.hpp b/boost/algorithm/cxx11/one_of.hpp new file mode 100644 index 0000000000..b6e8c77194 --- /dev/null +++ b/boost/algorithm/cxx11/one_of.hpp @@ -0,0 +1,82 @@ +/* + Copyright (c) Marshall Clow 2008-2012. + + Distributed under the Boost Software License, Version 1.0. (See accompanying + file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +*/ + +/// \file one_of.hpp +/// \brief Test ranges to see if only one element matches a value or predicate. +/// \author Marshall Clow + +#ifndef BOOST_ALGORITHM_ONE_OF_HPP +#define BOOST_ALGORITHM_ONE_OF_HPP + +#include <algorithm> // for std::find and std::find_if +#include <boost/algorithm/cxx11/none_of.hpp> + +#include <boost/range/begin.hpp> +#include <boost/range/end.hpp> + +namespace boost { namespace algorithm { + +/// \fn one_of ( InputIterator first, InputIterator last, Predicate p ) +/// \return true if the predicate 'p' is true for exactly one item in [first, last). +/// +/// \param first The start of the input sequence +/// \param last One past the end of the input sequence +/// \param p A predicate for testing the elements of the sequence +/// +template<typename InputIterator, typename Predicate> +bool one_of ( InputIterator first, InputIterator last, Predicate p ) +{ + InputIterator i = std::find_if (first, last, p); + if (i == last) + return false; // Didn't occur at all + return boost::algorithm::none_of (++i, last, p); +} + +/// \fn one_of ( const Range &r, Predicate p ) +/// \return true if the predicate 'p' is true for exactly one item in the range. +/// +/// \param r The input range +/// \param p A predicate for testing the elements of the range +/// +template<typename Range, typename Predicate> +bool one_of ( const Range &r, Predicate p ) +{ + return boost::algorithm::one_of ( boost::begin (r), boost::end (r), p ); +} + + +/// \fn one_of_equal ( InputIterator first, InputIterator last, const V &val ) +/// \return true if the value 'val' exists only once in [first, last). +/// +/// \param first The start of the input sequence +/// \param last One past the end of the input sequence +/// \param val A value to compare against +/// +template<typename InputIterator, typename V> +bool one_of_equal ( InputIterator first, InputIterator last, const V &val ) +{ + InputIterator i = std::find (first, last, val); // find first occurrence of 'val' + if (i == last) + return false; // Didn't occur at all + return boost::algorithm::none_of_equal (++i, last, val); +} + +/// \fn one_of_equal ( const Range &r, const V &val ) +/// \return true if the value 'val' exists only once in the range. +/// +/// \param r The input range +/// \param val A value to compare against +/// +template<typename Range, typename V> +bool one_of_equal ( const Range &r, const V &val ) +{ + return boost::algorithm::one_of_equal ( boost::begin (r), boost::end (r), val ); +} + +}} // namespace boost and algorithm + +#endif // BOOST_ALGORITHM_ALL_HPP |