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Viewing changes to external/nrefactory/ICSharpCode.NRefactory/TypeSystem/Implementation/SimpleInterningProvider.cs

  • Committer: Package Import Robot
  • Author(s): Jo Shields
  • Date: 2013-05-12 09:46:03 UTC
  • mto: This revision was merged to the branch mainline in revision 29.
  • Revision ID: package-import@ubuntu.com-20130512094603-mad323bzcxvmcam0
Tags: upstream-4.0.5+dfsg
Import upstream version 4.0.5+dfsg

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external/nrefactory/ICSharpCode.NRefactory/TypeSystem/Implementation/SimpleInterningProvider.cs
 
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// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
 
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// 
 
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// Permission is hereby granted, free of charge, to any person obtaining a copy of this
 
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// software and associated documentation files (the "Software"), to deal in the Software
 
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// without restriction, including without limitation the rights to use, copy, modify, merge,
 
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// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
 
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// to whom the Software is furnished to do so, subject to the following conditions:
 
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// 
 
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// The above copyright notice and this permission notice shall be included in all copies or
 
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// substantial portions of the Software.
 
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// 
 
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 
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// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
 
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// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 
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// DEALINGS IN THE SOFTWARE.
 
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using System;
 
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using System.Collections;
 
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using System.Collections.Generic;
 
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using System.Collections.ObjectModel;
 
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using System.Linq;
 
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using System.Runtime.CompilerServices;
 
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using ICSharpCode.NRefactory.Utils;
 
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namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 
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{
 
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        /// <summary>
 
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        /// Simple interning provider.
 
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        /// </summary>
 
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        public sealed class SimpleInterningProvider : InterningProvider
 
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        {
 
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                sealed class InterningComparer : IEqualityComparer<ISupportsInterning>
 
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                {
 
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                        public bool Equals(ISupportsInterning x, ISupportsInterning y)
 
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                        {
 
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                                return x.EqualsForInterning(y);
 
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                        }
 
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                        public int GetHashCode(ISupportsInterning obj)
 
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                        {
 
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                                return obj.GetHashCodeForInterning();
 
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                        }
 
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                }
 
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                sealed class ListComparer : IEqualityComparer<IEnumerable>
 
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                {
 
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                        public bool Equals(IEnumerable a, IEnumerable b)
 
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                        {
 
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                                if (a.GetType() != b.GetType())
 
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                                        return false;
 
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                                IEnumerator e1 = a.GetEnumerator();
 
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                                IEnumerator e2 = b.GetEnumerator();
 
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                                while (e1.MoveNext()) {
 
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                                        // e1 has more elements than e2; or elements are different
 
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                                        if (!e2.MoveNext() || e1.Current != e2.Current)
 
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                                                return false;
 
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                                }
 
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                                if (e2.MoveNext()) // e2 has more elements than e1
 
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                                        return false;
 
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                                // No need to dispose e1/e2: non-generic IEnumerator doesn't implement IDisposable,
 
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                                // and the underlying enumerator will likely be a List<T>.Enumerator which has an empty Dispose() method.
 
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                                return true;
 
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                        }
 
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                        public int GetHashCode(IEnumerable obj)
 
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                        {
 
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                                int hashCode = obj.GetType().GetHashCode();
 
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                                unchecked {
 
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                                        foreach (object o in obj) {
 
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                                                hashCode *= 27;
 
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                                                hashCode += RuntimeHelpers.GetHashCode(o);
 
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                                        }
 
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                                }
 
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                                return hashCode;
 
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                        }
 
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                }
 
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                Dictionary<object, object> byValueDict = new Dictionary<object, object>();
 
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                Dictionary<ISupportsInterning, ISupportsInterning> supportsInternDict = new Dictionary<ISupportsInterning, ISupportsInterning>(new InterningComparer());
 
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                Dictionary<IEnumerable, IEnumerable> listDict = new Dictionary<IEnumerable, IEnumerable>(new ListComparer());
 
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                public override ISupportsInterning Intern(ISupportsInterning obj)
 
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                {
 
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                        if (obj == null)
 
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                                return null;
 
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                        // ensure objects are frozen when we put them into the dictionary
 
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                        // note that Freeze may change the hash code of the object
 
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                        FreezableHelper.Freeze(obj);
 
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                        ISupportsInterning output;
 
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                        if (supportsInternDict.TryGetValue(obj, out output)) {
 
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                                return output;
 
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                        } else {
 
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                                supportsInternDict.Add(obj, obj);
 
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                                return obj;
 
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                        }
 
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                }
 
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                public override string Intern(string text)
 
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                {
 
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                        if (text == null)
 
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                                return null;
 
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                        object output;
 
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                        if (byValueDict.TryGetValue(text, out output))
 
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                                return (string)output;
 
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                        else
 
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                                return text;
 
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                }
 
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                public override object InternValue(object obj)
 
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                {
 
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                        if (obj == null)
 
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                                return null;
 
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                        object output;
 
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                        if (byValueDict.TryGetValue(obj, out output))
 
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                                return output;
 
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                        else
 
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                                return obj;
 
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                }
 
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                public override IList<T> InternList<T>(IList<T> list)
 
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                {
 
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                        if (list == null)
 
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                                return null;
 
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                        if (list.Count == 0)
 
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                                return EmptyList<T>.Instance;
 
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                        if (!list.IsReadOnly)
 
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                                list = new ReadOnlyCollection<T>(list);
 
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                        IEnumerable output;
 
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                        if (listDict.TryGetValue(list, out output))
 
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                                list = (IList<T>)output;
 
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                        else
 
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                                listDict.Add(list, list);
 
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                        return list;
 
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                }
 
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        }
 
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}