[overlay][range] Replace the explicit call to Range::erase() with version using std::copy() and traits::resize<>

include/boost/geometry/algorithms/detail/overlay/append_no_dups_or_spikes.hpp

@@ -15,6 +15,8 @@
 #include <boost/geometry/algorithms/detail/point_is_spike_or_equal.hpp>
 #include <boost/geometry/algorithms/detail/equals/point_point.hpp>
 
+#include <boost/geometry/util/range.hpp>
+
 
 namespace boost { namespace geometry
 {
@@ -108,7 +110,11 @@ inline void clean_closing_dups_and_spikes(Range& range,
     }
 
     typedef typename boost::range_iterator<Range>::type iterator_type;
-    const bool closed = geometry::closure<Range>::value == geometry::closed;
+    static const bool closed = geometry::closure<Range>::value == geometry::closed;
+
+// TODO: the following algorithm could be rewritten to first look for spikes
+// and then erase some number of points from the beginning of the Range
+
     bool found = false;
     do
     {
@@ -125,13 +131,13 @@ inline void clean_closing_dups_and_spikes(Range& range,
         // considered as a spike w.r.t. the last segment)
         if (point_is_spike_or_equal(*second, *ultimate, *first, robust_policy))
         {
-            range.erase(first);
+            range::erase(range, first);
             if (closed)
             {
                 // Remove closing last point
-                traits::resize<Range>::apply(range, boost::size(range) - 1);
+                range::resize(range, boost::size(range) - 1);
                 // Add new closing point
-                traits::push_back<Range>::apply(range, *boost::begin(range));
+                range::push_back(range, *boost::begin(range));
             }
             found = true;
         }

include/boost/geometry/util/range.hpp

@@ -14,6 +14,9 @@
 #ifndef BOOST_GEOMETRY_UTIL_RANGE_HPP
 #define BOOST_GEOMETRY_UTIL_RANGE_HPP
 
+#include <algorithm>
+
+#include <boost/assert.hpp>
 #include <boost/concept_check.hpp>
 #include <boost/range/concepts.hpp>
 #include <boost/range/begin.hpp>
@@ -21,6 +24,8 @@
 #include <boost/range/empty.hpp>
 #include <boost/range/size.hpp>
 
+#include <boost/geometry/core/mutable_range.hpp>
+
 namespace boost { namespace geometry { namespace range {
 
 // NOTE: For SinglePassRanges at could iterate over all elements until the i-th element is met.
@@ -105,6 +110,110 @@ back(BidirectionalRange & rng)
     return *(--boost::end(rng));
 }
 
+
+/*!
+\brief Short utility to conveniently clear a mutable range.
+       It uses traits::clear<>.
+\ingroup utility
+*/
+template <typename Range>
+inline void clear(Range & rng)
+{
+    // NOTE: this trait is probably not needed since it could be implemented using resize()
+    geometry::traits::clear<Range>::apply(rng);
+}
+
+/*!
+\brief Short utility to conveniently insert a new element at the end of a mutable range.
+       It uses boost::geometry::traits::push_back<>.
+\ingroup utility
+*/
+template <typename Range>
+inline void push_back(Range & rng,
+                      typename boost::range_value<Range>::type const& value)
+{
+    geometry::traits::push_back<Range>::apply(rng, value);
+}
+
+/*!
+\brief Short utility to conveniently resize a mutable range.
+       It uses boost::geometry::traits::resize<>.
+\ingroup utility
+*/
+template <typename Range>
+inline void resize(Range & rng,
+                   typename boost::range_size<Range>::type new_size)
+{
+    geometry::traits::resize<Range>::apply(rng, new_size);
+}
+
+
+/*!
+\brief Short utility to conveniently remove an element from the back of a mutable range.
+       It uses resize().
+\ingroup utility
+*/
+template <typename Range>
+inline void pop_back(Range & rng)
+{
+    BOOST_ASSERT(!boost::empty(rng));
+    range::resize(rng, boost::size(rng) - 1);
+}
+
+/*!
+\brief Short utility to conveniently remove an element from a mutable range.
+       It uses std::copy() and resize(). It requires mutable iterator as parameter.
+\ingroup utility
+*/
+template <typename Range>
+inline typename boost::range_iterator<Range>::type
+erase(Range & rng,
+      typename boost::range_iterator<Range>::type it)
+{
+    BOOST_ASSERT(!boost::empty(rng));
+    BOOST_ASSERT(it != boost::end(rng));
+
+    typename boost::range_iterator<Range>::type
+        next = it;
+    ++next;
+
+    std::copy(next, boost::end(rng), it);
+    range::resize(rng, boost::size(rng) - 1);
+
+    // NOTE: assuming that resize() doesn't invalidate the iterators
+    return it;
+}
+
+/*!
+\brief Short utility to conveniently remove a range of elements from a mutable range.
+       It uses std::copy() and resize(). It requires mutable iterators as parameters.
+\ingroup utility
+*/
+template <typename Range>
+inline typename boost::range_iterator<Range>::type
+erase(Range & rng,
+      typename boost::range_iterator<Range>::type first,
+      typename boost::range_iterator<Range>::type last)
+{
+    typename std::iterator_traits
+        <
+            typename boost::range_iterator<Range>::type
+        >::difference_type const diff = std::distance(first, last);
+    BOOST_ASSERT(diff >= 0);
+
+    std::size_t const count = static_cast<std::size_t>(diff);
+    BOOST_ASSERT(count <= boost::size(rng));
+    
+    if ( count > 0 )
+    {
+        std::copy(last, boost::end(rng), first);
+        range::resize(rng, boost::size(rng) - count);
+    }
+
+    // NOTE: assuming that resize() doesn't invalidate the iterators
+    return first;
+}
+
 }}} // namespace boost::geometry::range
 
 #endif // BOOST_GEOMETRY_UTIL_RANGE_HPP