Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Runtime.Serialization/System/Xml/XmlDictionary.cs

@@ -0,0 +1,122 @@
+//------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//------------------------------------------------------------
+namespace System.Xml
+{
+    using System;
+    using System.IO;
+    using System.Xml;
+    using System.Collections;
+    using System.Collections.Generic;
+    using System.Diagnostics;
+    using System.Text;
+    using System.Runtime.Serialization;
+
+    public class XmlDictionary : IXmlDictionary
+    {
+        static IXmlDictionary empty;
+        Dictionary<string, XmlDictionaryString> lookup;
+        XmlDictionaryString[] strings;
+        int nextId;
+
+        static public IXmlDictionary Empty
+        {
+            get
+            {
+                if (empty == null)
+                    empty = new EmptyDictionary();
+                return empty;
+            }
+        }
+
+        public XmlDictionary()
+        {
+            this.lookup = new Dictionary<string, XmlDictionaryString>();
+            this.strings = null;
+            this.nextId = 0;
+        }
+
+        public XmlDictionary(int capacity)
+        {
+            this.lookup = new Dictionary<string, XmlDictionaryString>(capacity);
+            this.strings = new XmlDictionaryString[capacity];
+            this.nextId = 0;
+        }
+
+        public virtual XmlDictionaryString Add(string value)
+        {
+            XmlDictionaryString str;
+            if (!this.lookup.TryGetValue(value, out str))
+            {
+                if (this.strings == null)
+                {
+                    this.strings = new XmlDictionaryString[4];
+                }
+                else if (this.nextId == this.strings.Length)
+                {
+                    int newSize = this.nextId * 2;
+                    if (newSize == 0)
+                        newSize = 4;
+                    Array.Resize(ref this.strings, newSize);
+                }
+                str = new XmlDictionaryString(this, value, this.nextId);
+                this.strings[this.nextId] = str;
+                this.lookup.Add(value, str);
+                this.nextId++;
+            }
+            return str;
+        }
+
+        public virtual bool TryLookup(string value, out XmlDictionaryString result)
+        {
+            return this.lookup.TryGetValue(value, out result);
+        }
+
+        public virtual bool TryLookup(int key, out XmlDictionaryString result)
+        {
+            if (key < 0 || key >= this.nextId)
+            {
+                result = null;
+                return false;
+            }
+            result = this.strings[key];
+            return true;
+        }
+
+        public virtual bool TryLookup(XmlDictionaryString value, out XmlDictionaryString result)
+        {
+            if (value == null)
+                throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new ArgumentNullException("value"));
+            if (value.Dictionary != this)
+            {
+                result = null;
+                return false;
+            }
+            result = value;
+            return true;
+        }
+
+        class EmptyDictionary : IXmlDictionary
+        {
+            public bool TryLookup(string value, out XmlDictionaryString result)
+            {
+                result = null;
+                return false;
+            }
+
+            public bool TryLookup(int key, out XmlDictionaryString result)
+            {
+                result = null;
+                return false;
+            }
+
+            public bool TryLookup(XmlDictionaryString value, out XmlDictionaryString result)
+            {
+                result = null;
+                return false;
+            }
+        }
+    }
+}
+
+