1#region Copyright notice and license
2// Protocol Buffers - Google's data interchange format
3// Copyright 2008 Google Inc.  All rights reserved.
4// https://developers.google.com/protocol-buffers/
5//
6// Redistribution and use in source and binary forms, with or without
7// modification, are permitted provided that the following conditions are
8// met:
9//
10//     * Redistributions of source code must retain the above copyright
11// notice, this list of conditions and the following disclaimer.
12//     * Redistributions in binary form must reproduce the above
13// copyright notice, this list of conditions and the following disclaimer
14// in the documentation and/or other materials provided with the
15// distribution.
16//     * Neither the name of Google Inc. nor the names of its
17// contributors may be used to endorse or promote products derived from
18// this software without specific prior written permission.
19//
20// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31#endregion
32
33using System;
34
35namespace Google.Protobuf
36{
37    internal sealed class JsonToken : IEquatable<JsonToken>
38    {
39        // Tokens with no value can be reused.
40        private static readonly JsonToken _true = new JsonToken(TokenType.True);
41        private static readonly JsonToken _false = new JsonToken(TokenType.False);
42        private static readonly JsonToken _null = new JsonToken(TokenType.Null);
43        private static readonly JsonToken startObject = new JsonToken(TokenType.StartObject);
44        private static readonly JsonToken endObject = new JsonToken(TokenType.EndObject);
45        private static readonly JsonToken startArray = new JsonToken(TokenType.StartArray);
46        private static readonly JsonToken endArray = new JsonToken(TokenType.EndArray);
47        private static readonly JsonToken endDocument = new JsonToken(TokenType.EndDocument);
48
49        internal static JsonToken Null { get { return _null; } }
50        internal static JsonToken False { get { return _false; } }
51        internal static JsonToken True { get { return _true; } }
52        internal static JsonToken StartObject{ get { return startObject; } }
53        internal static JsonToken EndObject { get { return endObject; } }
54        internal static JsonToken StartArray { get { return startArray; } }
55        internal static JsonToken EndArray { get { return endArray; } }
56        internal static JsonToken EndDocument { get { return endDocument; } }
57
58        internal static JsonToken Name(string name)
59        {
60            return new JsonToken(TokenType.Name, stringValue: name);
61        }
62
63        internal static JsonToken Value(string value)
64        {
65            return new JsonToken(TokenType.StringValue, stringValue: value);
66        }
67
68        internal static JsonToken Value(double value)
69        {
70            return new JsonToken(TokenType.Number, numberValue: value);
71        }
72
73        internal enum TokenType
74        {
75            Null,
76            False,
77            True,
78            StringValue,
79            Number,
80            Name,
81            StartObject,
82            EndObject,
83            StartArray,
84            EndArray,
85            EndDocument
86        }
87
88        // A value is a string, number, array, object, null, true or false
89        // Arrays and objects have start/end
90        // A document consists of a value
91        // Objects are name/value sequences.
92
93        private readonly TokenType type;
94        private readonly string stringValue;
95        private readonly double numberValue;
96
97        internal TokenType Type { get { return type; } }
98        internal string StringValue { get { return stringValue; } }
99        internal double NumberValue { get { return numberValue; } }
100
101        private JsonToken(TokenType type, string stringValue = null, double numberValue = 0)
102        {
103            this.type = type;
104            this.stringValue = stringValue;
105            this.numberValue = numberValue;
106        }
107
108        public override bool Equals(object obj)
109        {
110            return Equals(obj as JsonToken);
111        }
112
113        public override int GetHashCode()
114        {
115            unchecked
116            {
117                int hash = 17;
118                hash = hash * 31 + (int) type;
119                hash = hash * 31 + stringValue == null ? 0 : stringValue.GetHashCode();
120                hash = hash * 31 + numberValue.GetHashCode();
121                return hash;
122            }
123        }
124
125        public override string ToString()
126        {
127            switch (type)
128            {
129                case TokenType.Null:
130                    return "null";
131                case TokenType.True:
132                    return "true";
133                case TokenType.False:
134                    return "false";
135                case TokenType.Name:
136                    return "name (" + stringValue + ")";
137                case TokenType.StringValue:
138                    return "value (" + stringValue + ")";
139                case TokenType.Number:
140                    return "number (" + numberValue + ")";
141                case TokenType.StartObject:
142                    return "start-object";
143                case TokenType.EndObject:
144                    return "end-object";
145                case TokenType.StartArray:
146                    return "start-array";
147                case TokenType.EndArray:
148                    return "end-array";
149                case TokenType.EndDocument:
150                    return "end-document";
151                default:
152                    throw new InvalidOperationException("Token is of unknown type " + type);
153            }
154        }
155
156        public bool Equals(JsonToken other)
157        {
158            if (ReferenceEquals(other, null))
159            {
160                return false;
161            }
162            // Note use of other.numberValue.Equals rather than ==, so that NaN compares appropriately.
163            return other.type == type && other.stringValue == stringValue && other.numberValue.Equals(numberValue);
164        }
165    }
166}
167