Initial checkin of gRPC to third_party/

third_party/grpc/examples/csharp/route_guide/RouteGuide/RouteGuideUtil.cs

+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+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.
+        /// This code was taken from http://www.movable-type.co.uk/scripts/latlong.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)
+        {
+            double lat1 = start.GetLatitude();
+            double lat2 = end.GetLatitude();
+            double lon1 = start.GetLongitude();
+            double lon2 = end.GetLongitude();
+            int r = 6371000; // metres
+            double phi1 = ToRadians(lat1);
+            double phi2 = ToRadians(lat2);
+            double deltaPhi = ToRadians(lat2 - lat1);
+            double deltaLambda = ToRadians(lon2 - lon1);
+
+            double a = Math.Sin(deltaPhi / 2) * Math.Sin(deltaPhi / 2) + Math.Cos(phi1) * Math.Cos(phi2) * Math.Sin(deltaLambda / 2) * Math.Sin(deltaLambda / 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;
+        }
+    }
+}