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+// Copyright 2015 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Routeguide
+{
+    /// <summary>
+    /// Utility methods for the route guide example.
+    /// </summary>
+    public static class RouteGuideUtil
+    {
+        public const string DefaultFeaturesFile = "route_guide_db.json";
+
+        private const double CoordFactor = 1e7;
+
+        /// <summary>
+        /// Indicates whether the given feature exists (i.e. has a valid name).
+        /// </summary>
+        public static bool Exists(this Feature feature)
+        {
+            return feature != null && (feature.Name.Length != 0);
+        }
+
+        public static double GetLatitude(this Point point)
+        {
+            return point.Latitude / CoordFactor;
+        }
+
+        public static double GetLongitude(this Point point)
+        {
+            return point.Longitude / CoordFactor;
+        }
+
+        /// <summary>
+        /// Calculate the distance between two points using the "haversine" formula.
+        /// The formula is based on http://mathforum.org/library/drmath/view/51879.html
+        /// </summary>
+        /// <param name="start">the starting point</param>
+        /// <param name="end">the end point</param>
+        /// <returns>the distance between the points in meters</returns>
+        public static double GetDistance(this Point start, Point end)
+        {
+            int r = 6371000;  // earth radius in metres
+            double lat1 = ToRadians(start.GetLatitude());
+            double lat2 = ToRadians(end.GetLatitude());
+            double lon1 = ToRadians(start.GetLongitude());
+            double lon2 = ToRadians(end.GetLongitude());
+            double deltalat = lat2 - lat1;
+            double deltalon = lon2 - lon1;
+
+            double a = Math.Sin(deltalat / 2) * Math.Sin(deltalat / 2) + Math.Cos(lat1) * Math.Cos(lat2) * Math.Sin(deltalon / 2) * Math.Sin(deltalon / 2);
+            double c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
+            return r * c;
+        }
+
+        /// <summary>
+        /// Returns <c>true</c> if rectangular area contains given point.
+        /// </summary>
+        public static bool Contains(this Rectangle rectangle, Point point)
+        {
+            int left = Math.Min(rectangle.Lo.Longitude, rectangle.Hi.Longitude);
+            int right = Math.Max(rectangle.Lo.Longitude, rectangle.Hi.Longitude);
+            int top = Math.Max(rectangle.Lo.Latitude, rectangle.Hi.Latitude);
+            int bottom = Math.Min(rectangle.Lo.Latitude, rectangle.Hi.Latitude);
+            return (point.Longitude >= left && point.Longitude <= right && point.Latitude >= bottom && point.Latitude <= top);
+        }
+
+        private static double ToRadians(double val)
+        {
+            return (Math.PI / 180) * val;
+        }
+
+        /// <summary>
+        /// Parses features from a JSON file.
+        /// </summary>
+        public static List<Feature> ParseFeatures(string filename)
+        {
+            var features = new List<Feature>();
+            var jsonFeatures = JsonConvert.DeserializeObject<List<JsonFeature>>(File.ReadAllText(filename));
+
+            foreach(var jsonFeature in jsonFeatures)
+            {
+                features.Add(new Feature
+                {
+                    Name = jsonFeature.name,
+                    Location = new Point { Longitude = jsonFeature.location.longitude, Latitude = jsonFeature.location.latitude}
+                });
+            }
+            return features;
+        }
+
+        private class JsonFeature
+        {
+            public string name;
+            public JsonLocation location;
+        }
+
+        private class JsonLocation
+        {
+            public int longitude;
+            public int latitude;
+        }
+    }
+}