src/ProtocolBuffers/EnumLite.cs

#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// http://github.com/jskeet/dotnet-protobufs/
// Original C++/Java/Python code:
// http://code.google.com/p/protobuf/
//
// 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
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#endregion

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Text;

namespace Google.ProtocolBuffers {

  ///<summary>
  ///Interface for an enum value or value descriptor, to be used in FieldSet.
  ///The lite library stores enum values directly in FieldSets but the full
  ///library stores EnumValueDescriptors in order to better support reflection.
  ///</summary>
  public interface IEnumLite {
    int Number { get; }
    string Name { get; }
  }

  ///<summary>
  ///Interface for an object which maps integers to {@link EnumLite}s.
  ///{@link Descriptors.EnumDescriptor} implements this interface by mapping
  ///numbers to {@link Descriptors.EnumValueDescriptor}s.  Additionally,
  ///every generated enum type has a static method internalGetValueMap() which
  ///returns an implementation of this type that maps numbers to enum values.
  ///</summary>
  public interface IEnumLiteMap<T> : IEnumLiteMap
    where T : IEnumLite {
    new T FindValueByNumber(int number);
  }

  public interface IEnumLiteMap {
    bool IsValidValue(IEnumLite value);
    IEnumLite FindValueByNumber(int number);
  }

  public class EnumLiteMap<TEnum> : IEnumLiteMap<IEnumLite>
    where TEnum : struct, IComparable, IFormattable {
    
    struct EnumValue : IEnumLite {
      readonly TEnum value;
      public EnumValue(TEnum value) {
        this.value = value;
      }
      int IEnumLite.Number {
        get { return Convert.ToInt32(value); }
      }
      string IEnumLite.Name {
        get { return value.ToString(); }
      }
    }

    private readonly SortedList<int, IEnumLite> items;

    public EnumLiteMap() {
      items = new SortedList<int, IEnumLite>();
      foreach (TEnum evalue in Enum.GetValues(typeof(TEnum)))
        items.Add(Convert.ToInt32(evalue), new EnumValue(evalue));
    }

    IEnumLite IEnumLiteMap.FindValueByNumber(int number) {
      return FindValueByNumber(number);
    }

    public IEnumLite FindValueByNumber(int number) {
      IEnumLite val;
      return items.TryGetValue(number, out val) ? val : null;
    }

    public bool IsValidValue(IEnumLite value) {
      return items.ContainsKey(value.Number);
    }
  }
}