forked from boostorg/algorithm
83 lines
2.8 KiB
C++
83 lines
2.8 KiB
C++
/*
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Copyright (c) Marshall Clow 2008-2012.
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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*/
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/// \file one_of.hpp
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/// \brief Test ranges to see if only one element matches a value or predicate.
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/// \author Marshall Clow
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#ifndef BOOST_ALGORITHM_ONE_OF_HPP
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#define BOOST_ALGORITHM_ONE_OF_HPP
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#include <algorithm> // for std::find and std::find_if
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#include <boost/algorithm/cxx11/none_of.hpp>
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#include <boost/range/begin.hpp>
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#include <boost/range/end.hpp>
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namespace boost { namespace algorithm {
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/// \fn one_of ( InputIterator first, InputIterator last, Predicate p )
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/// \return true if the predicate 'p' is true for exactly one item in [first, last).
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///
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/// \param first The start of the input sequence
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/// \param last One past the end of the input sequence
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/// \param p A predicate for testing the elements of the sequence
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///
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template<typename InputIterator, typename Predicate>
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BOOST_CXX14_CONSTEXPR bool one_of ( InputIterator first, InputIterator last, Predicate p )
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{
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InputIterator i = std::find_if (first, last, p);
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if (i == last)
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return false; // Didn't occur at all
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return boost::algorithm::none_of (++i, last, p);
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}
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/// \fn one_of ( const Range &r, Predicate p )
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/// \return true if the predicate 'p' is true for exactly one item in the range.
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///
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/// \param r The input range
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/// \param p A predicate for testing the elements of the range
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///
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template<typename Range, typename Predicate>
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BOOST_CXX14_CONSTEXPR bool one_of ( const Range &r, Predicate p )
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{
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return boost::algorithm::one_of ( boost::begin (r), boost::end (r), p );
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}
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/// \fn one_of_equal ( InputIterator first, InputIterator last, const V &val )
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/// \return true if the value 'val' exists only once in [first, last).
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///
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/// \param first The start of the input sequence
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/// \param last One past the end of the input sequence
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/// \param val A value to compare against
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///
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template<typename InputIterator, typename V>
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bool one_of_equal ( InputIterator first, InputIterator last, const V &val )
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{
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InputIterator i = std::find (first, last, val); // find first occurrence of 'val'
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if (i == last)
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return false; // Didn't occur at all
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return boost::algorithm::none_of_equal (++i, last, val);
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}
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/// \fn one_of_equal ( const Range &r, const V &val )
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/// \return true if the value 'val' exists only once in the range.
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///
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/// \param r The input range
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/// \param val A value to compare against
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///
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template<typename Range, typename V>
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bool one_of_equal ( const Range &r, const V &val )
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{
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return boost::algorithm::one_of_equal ( boost::begin (r), boost::end (r), val );
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}
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}} // namespace boost and algorithm
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#endif // BOOST_ALGORITHM_ALL_HPP
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