From 17c0fa271c6926a4aa67254686c9559208ac040a Mon Sep 17 00:00:00 2001
From: Neil Groves <neilgroves@gmail.com>
Date: Mon, 3 Mar 2014 01:24:56 +0000
Subject: [PATCH] trac 9515 - fix for uniqued adaptor consistent with unique
 algorithm.

---
 .../boost/range/adaptor/adjacent_filtered.hpp | 58 ++++++--------
 test/adaptor_test/uniqued.cpp                 | 79 +++++++++++++++++++
 2 files changed, 103 insertions(+), 34 deletions(-)

diff --git a/include/boost/range/adaptor/adjacent_filtered.hpp b/include/boost/range/adaptor/adjacent_filtered.hpp
index f717cb3..159d8ee 100644
--- a/include/boost/range/adaptor/adjacent_filtered.hpp
+++ b/include/boost/range/adaptor/adjacent_filtered.hpp
@@ -62,54 +62,44 @@ namespace boost
                 , pred_t(pred)
                 , m_last(last)
             {
-                move_to_next_valid();
             }
 
             template<class OtherIter>
             skip_iterator( const skip_iterator<OtherIter, pred_t, default_pass>& other )
             : base_t(other.base())
             , pred_t(other)
-            , m_last(other.m_last) {}
-
-            void move_to_next_valid()
+            , m_last(other.m_last)
             {
-                iter_t& it = this->base_reference();
-                pred_t& bi_pred = *this;
-                if (it != m_last)
-                {
-                    if (default_pass)
-                    {
-                        iter_t nxt = ::boost::next(it);
-                        while (nxt != m_last && !bi_pred(*it, *nxt))
-                        {
-                            ++it;
-                            ++nxt;
-                        }
-                    }
-                    else
-                    {
-                        iter_t nxt = ::boost::next(it);
-                        for(; nxt != m_last; ++it, ++nxt)
-                        {
-                            if (bi_pred(*it, *nxt))
-                            {
-                                break;
-                            }
-                        }
-                        if (nxt == m_last)
-                        {
-                            it = m_last;
-                        }
-                    }
-                }
             }
 
             void increment()
             {
                 iter_t& it = this->base_reference();
                 BOOST_ASSERT( it != m_last );
+                pred_t& bi_pred = *this;
+                iter_t prev = it;
                 ++it;
-                move_to_next_valid();
+                if (it != m_last)
+                {
+                    if (default_pass)
+                    {
+                        while (it != m_last && !bi_pred(*prev, *it))
+                        {
+                            ++it;
+                            ++prev;
+                        }
+                    }
+                    else
+                    {
+                        for (; it != m_last; ++it, ++prev)
+                        {
+                            if (bi_pred(*prev, *it))
+                            {
+                                break;
+                            }
+                        }
+                    }
+                }
             }
 
             iter_t m_last;
diff --git a/test/adaptor_test/uniqued.cpp b/test/adaptor_test/uniqued.cpp
index 9c96744..fdf5454 100644
--- a/test/adaptor_test/uniqued.cpp
+++ b/test/adaptor_test/uniqued.cpp
@@ -9,6 +9,10 @@
 // For more information, see http://www.boost.org/libs/range/
 //
 #include <boost/range/adaptor/uniqued.hpp>
+#include <boost/range/adaptor/transformed.hpp>
+#include <boost/range/algorithm/unique_copy.hpp>
+#include <boost/range/algorithm_ext/push_back.hpp>
+#include <boost/algorithm/string/predicate.hpp>
 
 #include <boost/test/test_tools.hpp>
 #include <boost/test/unit_test.hpp>
@@ -74,9 +78,82 @@ namespace boost
             uniqued_test_impl< std::set< int > >();
             uniqued_test_impl< std::multiset< int > >();
         }
+
+class istring
+{
+public:
+    istring()
+        : m_value("")
+    {
     }
+
+    explicit istring(const char* value)
+        : m_value(value)
+    {
+    }
+
+    bool operator==(istring r) const
+    {
+        return boost::iequals(m_value, r.m_value);
+    }
+
+    bool operator!=(istring r) const
+    {
+        return !operator==(r);
+    }
+
+    inline friend std::ostream& operator<<(std::ostream& out, istring o)
+    {
+        return out << o.m_value;
+    }
+
+    const char* get() const { return m_value; }
+
+private:
+    const char* m_value;
+};
+
+struct istring_to_string
+{
+    typedef std::string result_type;
+
+    std::string operator()(istring s) const
+    {
+        return s.get();
+    }
+};
+
+// This is based on a test-case provided by Eric Neibler.
+void uniqued_return_first()
+{
+    using namespace boost::adaptors;
+
+    std::vector<istring> strs;
+    strs.push_back(istring("hello"));
+    strs.push_back(istring("hElLo"));
+    strs.push_back(istring("HELLO"));
+    strs.push_back(istring("ZZZZ"));
+
+    std::vector<istring> output1;
+
+    boost::unique_copy(strs, std::back_inserter(output1));
+
+    std::vector<istring> output2;
+    boost::push_back(output2, strs | uniqued);
+
+    std::vector<std::string> test1;
+    boost::push_back(test1, output1 | transformed(istring_to_string()));
+
+    std::vector<std::string> test2;
+    boost::push_back(test2, output2 | transformed(istring_to_string()));
+
+    BOOST_CHECK_EQUAL_COLLECTIONS(test1.begin(), test1.end(),
+                                  test2.begin(), test2.end());
 }
 
+    } // anonymous namespace
+} // namespace boost
+
 boost::unit_test::test_suite*
 init_unit_test_suite(int argc, char* argv[])
 {
@@ -85,5 +162,7 @@ init_unit_test_suite(int argc, char* argv[])
 
     test->add( BOOST_TEST_CASE( &boost::uniqued_test ) );
 
+    test->add(BOOST_TEST_CASE(&boost::uniqued_return_first));
+
     return test;
 }