forked from jasder/antlr
91 lines
3.2 KiB
C#
91 lines
3.2 KiB
C#
/*
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* [The "BSD license"]
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* Copyright (c) 2013 Terence Parr
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* Copyright (c) 2013 Sam Harwell
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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namespace Sharpen
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{
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using System.Collections.Generic;
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using System.Collections.ObjectModel;
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internal static class Collections
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{
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public static T[] EmptyList<T>()
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{
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return EmptyListImpl<T>.Instance;
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}
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#if NET_4_5
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public static ReadOnlyDictionary<TKey, TValue> EmptyMap<TKey, TValue>()
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#else
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public static IDictionary<TKey, TValue> EmptyMap<TKey, TValue>()
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#endif
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{
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return EmptyMapImpl<TKey, TValue>.Instance;
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}
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public static ReadOnlyCollection<T> SingletonList<T>(T item)
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{
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return new ReadOnlyCollection<T>(new T[] { item });
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}
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#if NET_4_5
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public static ReadOnlyDictionary<TKey, TValue> SingletonMap<TKey, TValue>(TKey key, TValue value)
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#else
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public static IDictionary<TKey, TValue> SingletonMap<TKey, TValue>(TKey key, TValue value)
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#endif
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{
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#if NET_4_5
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return new ReadOnlyDictionary<TKey,TValue>(new Dictionary<TKey, TValue> { { key, value } });
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#else
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return new Dictionary<TKey, TValue> { { key, value } };
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#endif
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}
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private static class EmptyListImpl<T>
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{
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public static readonly T[] Instance = new T[0];
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}
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private static class EmptyMapImpl<TKey, TValue>
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{
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#if NET_4_5
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public static readonly ReadOnlyDictionary<TKey, TValue> Instance =
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new ReadOnlyDictionary<TKey, TValue>(new Dictionary<TKey, TValue>());
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#else
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public static IDictionary<TKey, TValue> Instance
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{
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get
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{
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return new Dictionary<TKey, TValue>();
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}
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}
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#endif
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}
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}
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}
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