65 lines
2.6 KiB
C#
65 lines
2.6 KiB
C#
// Copyright (C) 2017, The Duplicati Team
|
|
// http://www.duplicati.com, info@duplicati.com
|
|
//
|
|
// This library is free software; you can redistribute it and/or modify
|
|
// it under the terms of the GNU Lesser General Public License as
|
|
// published by the Free Software Foundation; either version 2.1 of the
|
|
// License, or (at your option) any later version.
|
|
//
|
|
// This library is distributed in the hope that it will be useful, but
|
|
// WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
// Lesser General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Lesser General Public
|
|
// License along with this library; if not, write to the Free Software
|
|
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
using System;
|
|
using System.Collections.Generic;
|
|
using System.Security.Cryptography;
|
|
|
|
namespace Duplicati.Library.Utility
|
|
{
|
|
/// <summary>
|
|
/// This class helps picking the fastest hash algorithm implementation,
|
|
/// which is what <seealso cref="System.Security.Cryptography.HashAlgorithm.Create"/> should do, but does not.
|
|
/// </summary>
|
|
public static class HashAlgorithmHelper
|
|
{
|
|
/// <summary>
|
|
/// Cache of known types
|
|
/// </summary>
|
|
private static readonly Dictionary<string, Type> _knownTypes = new Dictionary<string, Type>(StringComparer.OrdinalIgnoreCase);
|
|
|
|
/// <summary>
|
|
/// Static initializer to pre-populate the type table
|
|
/// </summary>
|
|
static HashAlgorithmHelper()
|
|
{
|
|
_knownTypes["MD5"] = typeof(MD5Cng);
|
|
_knownTypes["SHA1"] = typeof(SHA1Cng);
|
|
_knownTypes["SHA256"] = typeof(SHA256Cng);
|
|
_knownTypes["SHA384"] = typeof(SHA384Cng);
|
|
_knownTypes["SHA512"] = typeof(SHA512Cng);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Create the hash algorithm with the specified name.
|
|
/// </summary>
|
|
/// <returns>The hash algorithm.</returns>
|
|
/// <param name="name">The name of the algorithm to create.</param>
|
|
public static HashAlgorithm Create(string name)
|
|
{
|
|
Type known;
|
|
if (!_knownTypes.TryGetValue(name, out known))
|
|
known = _knownTypes[name] = Type.GetType("System.Security.Cryptography." + name.ToUpperInvariant() + "Cng", false, true);
|
|
|
|
if (known == null || known.GetConstructor(Type.EmptyTypes) == null)
|
|
return HashAlgorithm.Create(name);
|
|
else
|
|
return (HashAlgorithm)Activator.CreateInstance(known);
|
|
|
|
}
|
|
}
|
|
}
|