整理

include/boost/range/algorithm/random_shuffle.hpp

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+//  Copyright Neil Groves 2009. Use, modification and
+//  distribution is subject to 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)
+//
+//
+// For more information, see http://www.boost.org/libs/range/
+//
+#ifndef BOOST_RANGE_ALGORITHM_RANDOM_SHUFFLE_HPP_INCLUDED
+#define BOOST_RANGE_ALGORITHM_RANDOM_SHUFFLE_HPP_INCLUDED
+
+#include <boost/concept_check.hpp>
+#include <boost/range/begin.hpp>
+#include <boost/range/end.hpp>
+#include <boost/range/concepts.hpp>
+#include <algorithm>
+#ifdef BOOST_NO_CXX98_RANDOM_SHUFFLE
+#include <cstdlib>
+#endif
+
+namespace boost
+{
+    namespace range
+    {
+
+        namespace detail
+        {
+#ifdef BOOST_NO_CXX98_RANDOM_SHUFFLE
+
+// wrap std::rand as UniformRandomBitGenerator
+struct wrap_rand
+{
+    typedef unsigned int result_type;
+
+    static BOOST_CONSTEXPR result_type (min)()
+    {
+        return 0;
+    }
+
+    static BOOST_CONSTEXPR result_type (max)()
+    {
+        return RAND_MAX;
+    }
+
+    result_type operator()()
+    {
+        return std::rand();
+    }
+};
+
+template< class RandomIt >
+inline void random_shuffle(RandomIt first, RandomIt last)
+{
+    std::shuffle(first, last, wrap_rand());
+}
+
+// wrap Generator as UniformRandomBitGenerator
+template< class Generator >
+struct wrap_generator
+{
+    typedef unsigned int result_type;
+    static const int max_arg = ((0u - 1u) >> 2) + 1;
+    Generator& g;
+
+    wrap_generator(Generator& gen) : g(gen) {}
+
+    static BOOST_CONSTEXPR result_type (min)()
+    {
+        return 0;
+    }
+
+    static BOOST_CONSTEXPR result_type (max)()
+    {
+        return max_arg - 1;
+    }
+
+    result_type operator()()
+    {
+        return static_cast<result_type>(g(max_arg));
+    }
+};
+
+template< class RandomIt, class Generator >
+inline void random_shuffle(RandomIt first, RandomIt last, Generator& gen)
+{
+    std::shuffle(first, last, wrap_generator< Generator >(gen));
+}
+
+#else
+    
+using std::random_shuffle;
+
+#endif  
+        } // namespace detail
+
+/// \brief template function random_shuffle
+///
+/// range-based version of the random_shuffle std algorithm
+///
+/// \pre RandomAccessRange is a model of the RandomAccessRangeConcept
+/// \pre Generator is a model of the UnaryFunctionConcept
+template<class RandomAccessRange>
+inline RandomAccessRange& random_shuffle(RandomAccessRange& rng)
+{
+    BOOST_RANGE_CONCEPT_ASSERT(( RandomAccessRangeConcept<RandomAccessRange> ));
+    detail::random_shuffle(boost::begin(rng), boost::end(rng));
+    return rng;
+}
+
+/// \overload
+template<class RandomAccessRange>
+inline const RandomAccessRange& random_shuffle(const RandomAccessRange& rng)
+{
+    BOOST_RANGE_CONCEPT_ASSERT(( RandomAccessRangeConcept<const RandomAccessRange> ));
+    detail::random_shuffle(boost::begin(rng), boost::end(rng));
+    return rng;
+}
+
+/// \overload
+template<class RandomAccessRange, class Generator>
+inline RandomAccessRange& random_shuffle(RandomAccessRange& rng, Generator& gen)
+{
+    BOOST_RANGE_CONCEPT_ASSERT(( RandomAccessRangeConcept<RandomAccessRange> ));
+    detail::random_shuffle(boost::begin(rng), boost::end(rng), gen);
+    return rng;
+}
+
+/// \overload
+template<class RandomAccessRange, class Generator>
+inline const RandomAccessRange& random_shuffle(const RandomAccessRange& rng, Generator& gen)
+{
+    BOOST_RANGE_CONCEPT_ASSERT(( RandomAccessRangeConcept<const RandomAccessRange> ));
+    detail::random_shuffle(boost::begin(rng), boost::end(rng), gen);
+    return rng;
+}
+
+    } // namespace range
+    using range::random_shuffle;
+} // namespace boost
+
+#endif // include guard