// Copyright (C) 2024, The Duplicati Team
// https://duplicati.com, hello@duplicati.com
// 
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// copy of this software and associated documentation files (the "Software"), 
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// and/or sell copies of the Software, and to permit persons to whom the 
// Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in 
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// 
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
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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.
    /// It falls back to the aforementioned System library when creation of
    /// the faster hash function fails.
    /// </summary>
    public static class HashAlgorithmHelper
    {
        /// <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)
        {
            try
            {
                return FasterHashing.FasterHash.Create(name);
            }
            // Only having OpenSSL 3 installed might trigger this exception.
            catch (EntryPointNotFoundException)
            {
                return HashAlgorithm.Create(name);
            }
        }
    }
}