third_party/protobuf/csharp/src/Google.Protobuf/Reflection/DescriptorUtil.cs

   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
  33 using System.Collections.Generic;
  34 using System.Collections.ObjectModel;
  35
  36 namespace Google.Protobuf.Reflection
  37 {
  38     /// <summary>
  39     /// Internal class containing utility methods when working with descriptors.
  40     /// </summary>
  41     internal static class DescriptorUtil
  42     {
  43         /// <summary>
  44         /// Equivalent to Func[TInput, int, TOutput] but usable in .NET 2.0. Only used to convert
  45         /// arrays.
  46         /// </summary>
  47         internal delegate TOutput IndexedConverter<TInput, TOutput>(TInput element, int index);
  48
  49         /// <summary>
  50         /// Converts the given array into a read-only list, applying the specified conversion to
  51         /// each input element.
  52         /// </summary>
  53         internal static IList<TOutput> ConvertAndMakeReadOnly<TInput, TOutput>
  54             (IList<TInput> input, IndexedConverter<TInput, TOutput> converter)
  55         {
  56             TOutput[] array = new TOutput[input.Count];
  57             for (int i = 0; i < array.Length; i++)
  58             {
  59                 array[i] = converter(input[i], i);
  60             }
  61             return new ReadOnlyCollection<TOutput>(array);
  62         }
  63     }
  64 }