Merge Boost.Algorithm to release branch

[SVN r78025]

include/boost/algorithm/cxx11/partition_point.hpp

@@ -0,0 +1,72 @@
+/* 
+   Copyright (c) Marshall Clow 2011-2012.
+
+   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  partition_point.hpp
+/// \brief Find the partition point in a sequence
+/// \author Marshall Clow
+
+#ifndef BOOST_ALGORITHM_PARTITION_POINT_HPP
+#define BOOST_ALGORITHM_PARTITION_POINT_HPP
+
+#include <algorithm>	// for std::partition_point, if available
+
+#include <boost/range/begin.hpp>
+#include <boost/range/end.hpp>
+
+namespace boost { namespace algorithm {
+
+#if __cplusplus >= 201103L
+//  Use the C++11 versions of iota if it is available
+using std::partition_point;      // Section 25.3.13
+#else
+/// \fn partition_point ( ForwardIterator first, ForwardIterator last, Predicate p )
+/// \brief Given a partitioned range, returns the partition point, i.e, the first element 
+///		that does not satisfy p
+/// 
+/// \param first    The start of the input sequence
+/// \param last     One past the end of the input sequence
+/// \param p        The predicate to test the values with
+/// \note           This function is part of the C++2011 standard library.
+///  We will use the standard one if it is available, 
+///  otherwise we have our own implementation.
+template <typename ForwardIterator, typename Predicate>
+ForwardIterator partition_point ( ForwardIterator first, ForwardIterator last, Predicate p )
+{
+    std::size_t dist = std::distance ( first, last );
+    while ( first != last ) {
+        std::size_t d2 = dist / 2;
+        ForwardIterator ret_val = first;
+        std::advance (ret_val, d2);
+        if (p (*ret_val)) {
+            first = ++ret_val;
+            dist -= d2 + 1;
+            }
+        else {
+            last = ret_val;
+            dist = d2;
+            }
+        }
+    return first;
+}
+#endif
+
+/// \fn partition_point ( Range &r, Predicate p )
+/// \brief Given a partitioned range, returns the partition point
+/// 
+/// \param r        The input range
+/// \param p        The predicate to test the values with
+///
+template <typename Range, typename Predicate>
+typename boost::range_iterator<Range> partition_point ( Range &r, Predicate p )
+{
+    return boost::algorithm::partition_point (boost::begin(r), boost::end(r), p);
+}
+
+
+}}
+
+#endif  // BOOST_ALGORITHM_PARTITION_POINT_HPP