diff --git a/include/mapnik/offset_converter.hpp b/include/mapnik/offset_converter.hpp
index 3c2659280..4adba6ac8 100644
--- a/include/mapnik/offset_converter.hpp
+++ b/include/mapnik/offset_converter.hpp
@@ -46,7 +46,6 @@ template <typename Geometry>
 struct MAPNIK_DECL offset_converter
 {
     typedef std::size_t size_type;
-    //typedef typename Geometry::value_type value_type;
 
     offset_converter(Geometry & geom)
         : geom_(geom)
@@ -62,10 +61,7 @@ struct MAPNIK_DECL offset_converter
     enum status
     {
         initial,
-        process,
-        last_vertex,
-        angle_joint,
-        end
+        process
     };
 
     double get_offset() const
@@ -98,19 +94,27 @@ struct MAPNIK_DECL offset_converter
     unsigned vertex(double * x, double * y)
     {
         if (offset_ == 0.0)
+        {
             return geom_.vertex(x, y);
+        }
 
         if (status_ == initial)
+        {
             init_vertices();
+        }
 
         if (pos_ >= vertices_.size())
+        {
             return SEG_END;
+        }
 
         pre_ = (pos_ ? cur_ : pre_first_);
-        cur_ = vertices_[pos_++];
+        cur_ = vertices_.at(pos_++);
 
         if (pos_ == vertices_.size())
+        {
             return output_vertex(x, y);
+        }
 
         double const check_dist = offset_ * threshold_;
         double const check_dist2 = check_dist * check_dist;
@@ -127,13 +131,19 @@ struct MAPNIK_DECL offset_converter
             double const dy = u0.y - cur_.y;
 
             if (dx*dx + dy*dy > check_dist2)
+            {
                 break;
+            }
 
             if (!intersection(pre_, cur_, &vt, u0, u1, &ut))
+            {
                 continue;
+            }
 
             if (vt < 0.0 || vt > t || ut < 0.0 || ut > 1.0)
+            {
                 continue;
+            }
 
             t = vt;
             pos_ = i+1;
@@ -162,11 +172,17 @@ private:
     static double explement_reflex_angle(double angle)
     {
         if (angle > pi)
+        {
             return angle - 2 * pi;
+        }
         else if (angle < -pi)
+        {
             return angle + 2 * pi;
+        }
         else
+        {
             return angle;
+        }
     }
 
     static bool intersection(vertex2d const& u1, vertex2d const& u2, double* ut,
@@ -186,7 +202,9 @@ private:
             double const dn = vx * uy - ux * vy;
 
             if (dn > -1e-6 && dn < 1e-6)
+            {
                 return false; // they are parallel
+            }
 
             *vt = up / dn;
             *ut = (*vt * vx + dx) / ux;
@@ -200,7 +218,9 @@ private:
             double const dn = vy * ux - uy * vx;
 
             if (dn > -1e-6 && dn < 1e-6)
+            {
                 return false; // they are parallel
+            }
 
             *vt = up / dn;
             *ut = (*vt * vy + dy) / uy;
@@ -251,7 +271,9 @@ private:
     status init_vertices()
     {
         if (status_ != initial) // already initialized
+        {
             return status_;
+        }
 
         vertex2d v1(vertex2d::no_init);
         vertex2d v2(vertex2d::no_init);
@@ -261,7 +283,9 @@ private:
         v2.cmd = geom_.vertex(&v2.x, &v2.y);
 
         if (v2.cmd == SEG_END) // not enough vertices in source
+        {
             return status_ = process;
+        }
 
         double angle_a = 0;
         double angle_b = std::atan2((v2.y - v1.y), (v2.x - v1.x));
@@ -290,16 +314,24 @@ private:
             if (offset_ < 0.0)
             {
                 if (joint_angle > 0.0)
+                {
                     joint_angle = joint_angle - 2 * pi;
+                }
                 else
-                    bulge_steps = 1 + int(std::floor(half_turns / pi));
+                {
+                    bulge_steps = 1 + static_cast<int>(std::floor(half_turns / pi));
+                }
             }
             else
             {
                 if (joint_angle < 0.0)
+                {
                     joint_angle = joint_angle + 2 * pi;
+                }
                 else
-                    bulge_steps = 1 + int(floor(half_turns / pi));
+                {
+                    bulge_steps = 1 + static_cast<int>(std::floor(half_turns / pi));
+                }
             }
 
             #ifdef MAPNIK_LOG
@@ -322,7 +354,7 @@ private:
             displace(w, v1, angle_a);
             push_vertex(w);
 
-            for (int s = 0; ++s < bulge_steps; )
+            for (int s = 0; ++s < bulge_steps;)
             {
                 displace(w, v1, angle_a + (joint_angle * s) / bulge_steps);
                 push_vertex(w);