feat: enable to use legacy FNV hashes

sample/SampleWebApp/appsettings.example.json

@@ -17,6 +17,7 @@
     "SuppressException": false,
     "UseSslStream": false,
     "UseIPv6": false,
+    "UseLegacyNodeLocator": false,
     "Transcoder": "MessagePackTranscoder",
     "KeyTransformer": "Enyim.Caching.Memcached.SHA1KeyTransformer",
     "Authentication": {

sample/SampleWebApp/appsettings.json

@@ -15,6 +15,7 @@
       "queueTimeout": "00:00:00.150"
     },
     "suppressException": false,
+    "UseLegacyNodeLocator": false,
     "Transcoder": "MessagePackTranscoder"
   },
 

src/Enyim.Caching/Configuration/MemcachedClientConfiguration.cs

@@ -1,16 +1,16 @@
-using System;
-using System.Collections.Generic;
-using System.Net;
 using Enyim.Caching.Memcached;
-using Enyim.Reflection;
 using Enyim.Caching.Memcached.Protocol.Binary;
+using Enyim.Caching.Memcached.Transcoders;
+using Enyim.Reflection;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
-using Microsoft.Extensions.Configuration;
+using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Net;
 using System.Net.Security;
 using System.Net.Sockets;
-using Enyim.Caching.Memcached.Transcoders;
 
 namespace Enyim.Caching.Configuration
 {
@@ -150,7 +150,14 @@ public MemcachedClientConfiguration(
 
             if (NodeLocator == null)
             {
-                NodeLocator = options.Servers.Count > 1 ? typeof(DefaultNodeLocator) : typeof(SingleNodeLocator);
+                if (options.Servers.Count > 1)
+                {
+                    NodeLocator = options.UseLegacyNodeLocator ? typeof(LegacyNodeLocator) : typeof(DefaultNodeLocator);
+                }
+                else
+                {
+                    NodeLocator = typeof(SingleNodeLocator);
+                }
             }
 
             if (!string.IsNullOrEmpty(options.Transcoder))

src/Enyim.Caching/Configuration/MemcachedClientOptions.cs

@@ -2,9 +2,7 @@
 using Microsoft.Extensions.Options;
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Net.Security;
-using System.Threading.Tasks;
 
 namespace Enyim.Caching.Configuration
 {
@@ -16,6 +14,8 @@ public class MemcachedClientOptions : IOptions<MemcachedClientOptions>
 
         public List<Server> Servers { get; set; } = new List<Server>();
 
+        public bool UseLegacyNodeLocator { get; set; }
+
         public Authentication Authentication { get; set; }
 
         public string KeyTransformer { get; set; }

src/Enyim.Caching/FnvHash.cs

@@ -10,7 +10,7 @@ namespace Enyim
     /// Calculation found at http://lists.danga.com/pipermail/memcached/2007-April/003846.html, but 
     /// it is pretty much available everywhere
     /// </remarks>
-    public class FNV64 : System.Security.Cryptography.HashAlgorithm, IUIntHashAlgorithm
+    public class FNV64 : HashAlgorithm, IUIntHashAlgorithm
     {
         protected const ulong Init = 0xcbf29ce484222325L;
         protected const ulong Prime = 0x100000001b3L;
@@ -20,10 +20,10 @@ public class FNV64 : System.Security.Cryptography.HashAlgorithm, IUIntHashAlgori
         /// <summary>
         /// Initializes a new instance of the <see cref="T:FNV64"/> class.
         /// </summary>
-        public FNV64()
+        public FNV64(bool initialize)
         {
             //base.HashSize = 64;
-            Initialize();
+            if (initialize) Initialize();
         }
 
         /// <summary>
@@ -76,6 +76,8 @@ uint IUIntHashAlgorithm.ComputeHash(byte[] data)
     /// </summary>
     public sealed class FNV64a : FNV64
     {
+        public FNV64a(bool initialize) : base(initialize) { }
+
         /// <summary>Routes data written to the object into the <see cref="T:FNV64" /> hash algorithm for computing the hash.</summary>
         /// <param name="array">The input data. </param>
         /// <param name="ibStart">The offset into the byte array from which to begin using data. </param>
@@ -108,9 +110,9 @@ public class FNV1 : HashAlgorithm, IUIntHashAlgorithm
         /// <summary>
         /// Initializes a new instance of the <see cref="T:FNV1a"/> class.
         /// </summary>
-        public FNV1()
+        public FNV1(bool initialize)
         {
-            Initialize();
+            if (initialize) Initialize();
         }
 
         /// <summary>
@@ -163,6 +165,8 @@ uint IUIntHashAlgorithm.ComputeHash(byte[] data)
     /// </summary>
     public class FNV1a : FNV1
     {
+        public FNV1a(bool initialize) : base(initialize) { }
+
         /// <summary>Routes data written to the object into the <see cref="T:FNV1a" /> hash algorithm for computing the hash.</summary>
         /// <param name="array">The input data. </param>
         /// <param name="ibStart">The offset into the byte array from which to begin using data. </param>
@@ -185,6 +189,8 @@ protected override void HashCore(byte[] array, int ibStart, int cbSize)
     /// <remarks>Algorithm found at http://bretm.home.comcast.net/hash/6.html</remarks>
     public class ModifiedFNV : FNV1a
     {
+        public ModifiedFNV(bool initialize) : base(initialize) { }
+
         /// <summary>
         /// Returns the computed <see cref="T:ModifiedFNV" /> hash value after all data has been written to the object.
         /// </summary>

src/Enyim.Caching/Memcached/Locators/DefaultNodeLocator.cs

@@ -1,6 +1,6 @@
 using System;
-using System.Linq;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text;
 using System.Threading;
 
@@ -42,7 +42,7 @@ private void BuildIndex(List<IMemcachedNode> nodes)
 
             foreach (IMemcachedNode node in nodes)
             {
-                var tmpKeys = DefaultNodeLocator.GenerateKeys(node, _serverAddressMutations);
+                var tmpKeys = GenerateKeys(node, _serverAddressMutations);
 
                 for (var i = 0; i < tmpKeys.Length; i++)
                 {
@@ -126,7 +126,7 @@ private IMemcachedNode FindNode(string key)
         {
             if (_keys.Length == 0) return null;
 
-            uint itemKeyHash = BitConverter.ToUInt32(new FNV1a().ComputeHash(Encoding.UTF8.GetBytes(key)), 0);
+            uint itemKeyHash = BitConverter.ToUInt32(new FNV1a(true).ComputeHash(Encoding.UTF8.GetBytes(key)), 0);
             // get the index of the server assigned to this hash
             int foundIndex = Array.BinarySearch<uint>(_keys, itemKeyHash);
 
@@ -168,11 +168,11 @@ private static uint[] GenerateKeys(IMemcachedNode node, int numberOfKeys)
             // server will be stored with keys 0x0000aabb & 0x0000ccdd
             // (or a bit differently based on the little/big indianness of the host)
             string address = node.EndPoint.ToString();
-            var fnv = new FNV1a();
+            var fnv = new FNV1a(true);
 
             for (int i = 0; i < numberOfKeys; i++)
             {
-                byte[] data = fnv.ComputeHash(Encoding.UTF8.GetBytes(String.Concat(i, "-", address)));
+                byte[] data = fnv.ComputeHash(Encoding.UTF8.GetBytes(string.Concat(i, "-", address)));
 
                 for (int h = 0; h < PartCount; h++)
                 {