整理

include/boost/algorithm/cxx11/one_of.hpp

@@ -0,0 +1,91 @@
+/* 
+   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 <boost/config.hpp>
+#include <boost/range/begin.hpp>
+#include <boost/range/end.hpp>
+
+#include <boost/algorithm/cxx11/none_of.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> 
+BOOST_CXX14_CONSTEXPR bool one_of ( InputIterator first, InputIterator last, Predicate p )
+{
+//  find_if
+    for (; first != last; ++first)
+        if (p(*first))
+            break;
+
+    if (first == last)
+        return false;    // Didn't occur at all
+    return boost::algorithm::none_of (++first, 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> 
+BOOST_CXX14_CONSTEXPR 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> 
+BOOST_CXX14_CONSTEXPR bool one_of_equal ( InputIterator first, InputIterator last, const V &val )
+{
+//  find
+    for (; first != last; ++first)
+        if (*first == val)
+            break;
+
+    if (first == last)
+        return false;                    // Didn't occur at all
+    return boost::algorithm::none_of_equal (++first, 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> 
+BOOST_CXX14_CONSTEXPR 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