[boost][range] - Update to relax preconditions for the strided adaptor, and numerous fixes to inspection report issues.

[SVN r67419]

include/boost/range/algorithm/search_n.hpp

@@ -15,6 +15,7 @@
 #include <boost/range/concepts.hpp>
 #include <boost/range/detail/range_return.hpp>
 #include <boost/range/value_type.hpp>
+#include <iterator>
 #include <algorithm>
 
 namespace boost
@@ -22,6 +23,218 @@ namespace boost
     namespace range
     {
 
+namespace range_detail
+{
+    // Rationale: search_n is implemented rather than delegate to
+    // the standard library implementation because some standard
+    // library implementations are broken eg. MSVC.
+
+    // search_n forward iterator version
+    template<typename ForwardIterator, typename Integer, typename Value>
+    inline ForwardIterator
+    search_n_impl(ForwardIterator first, ForwardIterator last, Integer count,
+                  const Value& value, std::forward_iterator_tag)
+    {
+        first = std::find(first, last, value);
+        while (first != last)
+        {
+            typename std::iterator_traits<ForwardIterator>::difference_type n = count;
+            ForwardIterator i = first;
+            ++i;
+            while (i != last && n != 1 && *i==value)
+            {
+                ++i;
+                --n;
+            }
+            if (n == 1)
+                return first;
+            if (i == last)
+                return last;
+            first = std::find(++i, last, value);
+        }
+        return last;
+    }
+
+    // search_n random-access iterator version
+    template<typename RandomAccessIterator, typename Integer, typename Value>
+    inline RandomAccessIterator
+    search_n_impl(RandomAccessIterator first, RandomAccessIterator last,
+                  Integer count, const Value& value,
+                  std::random_access_iterator_tag)
+    {
+        typedef typename std::iterator_traits<RandomAccessIterator>::difference_type difference_t;
+
+        difference_t tail_size = last - first;
+        const difference_t pattern_size = count;
+
+        if (tail_size < pattern_size)
+            return last;
+
+        const difference_t skip_offset = pattern_size - 1;
+        RandomAccessIterator look_ahead = first + skip_offset;
+        tail_size -= pattern_size;
+
+        while (1)
+        {
+            // look_ahead here is pointing to the last element of the
+            // next possible match
+            while (!(*look_ahead == value)) // skip loop...
+            {
+                if (tail_size < pattern_size)
+                    return last; // no match
+                look_ahead += pattern_size;
+                tail_size -= pattern_size;
+            }
+            difference_t remainder = skip_offset;
+            for (RandomAccessIterator back_track = look_ahead - 1;
+                    *back_track == value; --back_track)
+            {
+                if (--remainder == 0)
+                {
+                    return look_ahead - skip_offset; // matched
+                }
+            }
+            if (remainder > tail_size)
+                return last; // no match
+            look_ahead += remainder;
+            tail_size -= remainder;
+        }
+
+        return last;
+    }
+
+    // search_n for forward iterators using a binary predicate
+    // to determine a match
+    template<typename ForwardIterator, typename Integer, typename Value,
+             typename BinaryPredicate>
+    inline ForwardIterator
+    search_n_impl(ForwardIterator first, ForwardIterator last,
+                  Integer count, const Value& value,
+                  BinaryPredicate pred, std::forward_iterator_tag)
+    {
+        typedef typename std::iterator_traits<ForwardIterator>::difference_type difference_t;
+
+        while (first != last && !static_cast<bool>(pred(*first, value)))
+            ++first;
+
+        while (first != last)
+        {
+            difference_t n = count;
+            ForwardIterator i = first;
+            ++i;
+            while (i != last && n != 1 && static_cast<bool>(pred(*i, value)))
+            {
+                ++i;
+                --n;
+            }
+            if (n == 1)
+                return first;
+            if (i == last)
+                return last;
+            first = ++i;
+            while (first != last && !static_cast<bool>(pred(*first, value)))
+                ++first;
+        }
+        return last;
+    }
+
+    // search_n for random-access iterators using a binary predicate
+    // to determine a match
+    template<typename RandomAccessIterator, typename Integer,
+             typename Value, typename BinaryPredicate>
+    inline RandomAccessIterator
+    search_n_impl(RandomAccessIterator first, RandomAccessIterator last,
+                  Integer count, const Value& value,
+                  BinaryPredicate pred, std::random_access_iterator_tag)
+    {
+        typedef typename std::iterator_traits<RandomAccessIterator>::difference_type difference_t;
+
+        difference_t tail_size = last - first;
+        const difference_t pattern_size = count;
+
+        if (tail_size < pattern_size)
+            return last;
+
+        const difference_t skip_offset = pattern_size - 1;
+        RandomAccessIterator look_ahead = first + skip_offset;
+        tail_size -= pattern_size;
+
+        while (1)
+        {
+            // look_ahead points to the last element of the next
+            // possible match
+            while (!static_cast<bool>(pred(*look_ahead, value))) // skip loop
+            {
+                if (tail_size < pattern_size)
+                    return last; // no match
+                look_ahead += pattern_size;
+                tail_size -= pattern_size;
+            }
+            difference_t remainder = skip_offset;
+            for (RandomAccessIterator back_track = look_ahead - 1;
+                    pred(*back_track, value); --back_track)
+            {
+                if (--remainder == 0)
+                    return look_ahead -= skip_offset; // success
+            }
+            if (remainder > tail_size)
+            {
+                return last; // no match
+            }
+            look_ahead += remainder;
+            tail_size -= remainder;
+        }
+    }
+
+    template<typename ForwardIterator, typename Integer, typename Value>
+    inline ForwardIterator
+    search_n_impl(ForwardIterator first, ForwardIterator last,
+                  Integer count, const Value& value)
+    {
+        BOOST_RANGE_CONCEPT_ASSERT((ForwardIteratorConcept<ForwardIterator>));
+        BOOST_RANGE_CONCEPT_ASSERT((EqualityComparableConcept<Value>));
+        BOOST_RANGE_CONCEPT_ASSERT((EqualityComparableConcept<typename std::iterator_traits<ForwardIterator>::value_type>));
+        //BOOST_RANGE_CONCEPT_ASSERT((EqualityComparableConcept2<typename std::iterator_traits<ForwardIterator>::value_type, Value>));
+
+        typedef typename std::iterator_traits<ForwardIterator>::iterator_category cat_t;
+
+        if (count <= 0)
+            return first;
+        if (count == 1)
+            return std::find(first, last, value);
+        return range_detail::search_n_impl(first, last, count, value, cat_t());
+    }
+
+    template<typename ForwardIterator, typename Integer, typename Value,
+             typename BinaryPredicate>
+    inline ForwardIterator
+    search_n_impl(ForwardIterator first, ForwardIterator last,
+                  Integer count, const Value& value,
+                  BinaryPredicate pred)
+    {
+        BOOST_RANGE_CONCEPT_ASSERT((ForwardIteratorConcept<ForwardIterator>));
+        BOOST_RANGE_CONCEPT_ASSERT((
+            BinaryPredicateConcept<
+                BinaryPredicate,
+                typename std::iterator_traits<BinaryPredicate>::value_type,
+                Value>
+            ));
+
+        typedef typename std::iterator_traits<ForwardIterator>::iterator_category cat_t;
+
+        if (count <= 0)
+            return first;
+        if (count == 1)
+        {
+            while (first != last && !static_cast<bool>(pred(*first, value)))
+                ++first;
+            return first;
+        }
+        return range_detail::search_n_impl(first, last, count,
+                                           value, pred, cat_t());
+    }
+} // namespace range_detail
+
 /// \brief template function search
 ///
 /// range-based version of the search std algorithm
@@ -36,7 +249,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type
 search_n(ForwardRange& rng, Integer count, const Value& value)
 {
     BOOST_RANGE_CONCEPT_ASSERT((ForwardRangeConcept<ForwardRange>));
-    return std::search_n(boost::begin(rng),boost::end(rng), count, value);
+    return range_detail::search_n_impl(boost::begin(rng),boost::end(rng), count, value);
 }
 
 /// \overload
@@ -45,7 +258,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<const ForwardRange>::type
 search_n(const ForwardRange& rng, Integer count, const Value& value)
 {
     BOOST_RANGE_CONCEPT_ASSERT((ForwardRangeConcept<const ForwardRange>));
-    return std::search_n(boost::begin(rng), boost::end(rng), count, value);
+    return range_detail::search_n_impl(boost::begin(rng), boost::end(rng), count, value);
 }
 
 /// \overload
@@ -58,7 +271,7 @@ search_n(ForwardRange& rng, Integer count, const Value& value,
     BOOST_RANGE_CONCEPT_ASSERT((ForwardRangeConcept<ForwardRange>));
     BOOST_RANGE_CONCEPT_ASSERT((BinaryPredicateConcept<BinaryPredicate,
         BOOST_DEDUCED_TYPENAME range_value<ForwardRange>::type, const Value&>));
-    return std::search_n(boost::begin(rng), boost::end(rng),
+    return range_detail::search_n_impl(boost::begin(rng), boost::end(rng),
         count, value, binary_pred);
 }
 
@@ -72,7 +285,7 @@ search_n(const ForwardRange& rng, Integer count, const Value& value,
     BOOST_RANGE_CONCEPT_ASSERT((ForwardRangeConcept<const ForwardRange>));
     BOOST_RANGE_CONCEPT_ASSERT((BinaryPredicateConcept<BinaryPredicate,
         BOOST_DEDUCED_TYPENAME range_value<const ForwardRange>::type, const Value&>));
-    return std::search_n(boost::begin(rng), boost::end(rng),
+    return range_detail::search_n_impl(boost::begin(rng), boost::end(rng),
         count, value, binary_pred);
 }
 
@@ -86,7 +299,7 @@ search_n(ForwardRange& rng, Integer count, const Value& value)
 {
     BOOST_RANGE_CONCEPT_ASSERT((ForwardRangeConcept<ForwardRange>));
     return range_return<ForwardRange,re>::
-        pack(std::search_n(boost::begin(rng),boost::end(rng),
+        pack(range_detail::search_n_impl(boost::begin(rng),boost::end(rng),
                            count, value),
              rng);
 }
@@ -99,7 +312,7 @@ search_n(const ForwardRange& rng, Integer count, const Value& value)
 {
     BOOST_RANGE_CONCEPT_ASSERT((ForwardRangeConcept<const ForwardRange>));
     return range_return<const ForwardRange,re>::
-        pack(std::search_n(boost::begin(rng), boost::end(rng),
+        pack(range_detail::search_n_impl(boost::begin(rng), boost::end(rng),
                            count, value),
              rng);
 }
@@ -116,7 +329,7 @@ search_n(ForwardRange& rng, Integer count, const Value& value,
         BOOST_DEDUCED_TYPENAME range_value<ForwardRange>::type,
         const Value&>));
     return range_return<ForwardRange,re>::
-        pack(std::search_n(boost::begin(rng), boost::end(rng),
+        pack(range_detail::search_n_impl(boost::begin(rng), boost::end(rng),
                            count, value, pred),
              rng);
 }
@@ -133,7 +346,7 @@ search_n(const ForwardRange& rng, Integer count, const Value& value,
         BOOST_DEDUCED_TYPENAME range_value<const ForwardRange>::type,
         const Value&>));
     return range_return<const ForwardRange,re>::
-        pack(std::search_n(boost::begin(rng), boost::end(rng),
+        pack(range_detail::search_n_impl(boost::begin(rng), boost::end(rng),
                            count, value, pred),
              rng);
 }