4 files changed, 85 insertions(+), 42 deletions(-)

M Core/NosSmooth.Cryptography/ClientLoginCryptography.cs
M Core/NosSmooth.Cryptography/Extensions/StringExtensions.cs
M Core/NosSmooth.Cryptography/ServerLoginCryptography.cs
M Core/NosSmooth.Cryptography/ServerWorldCryptography.cs

@@ 20,7 20,7 @@ public class ClientLoginCryptography : ICryptography
     {
         try
         {
-            var output = new StringBuilder();
+            var output = new StringBuilder(bytes.Length);
             foreach (var c in bytes)
             {
                 output.Append(Convert.ToChar(c - 0xF));

@@ 23,6 23,75 @@ public static class StringExtensions
     }
 
     /// <summary>
+    /// Split a string without any allocation.
+    /// </summary>
+    /// <param name="str">The string to split.</param>
+    /// <param name="split">The char to split with.</param>
+    /// <returns>The split enumerator.</returns>
+    public static SplitEnumerator SplitAllocationless(this string str, char split)
+    {
+        return new SplitEnumerator(str.AsSpan(), split);
+    }
+
+    /// <summary>
+    /// An enumerator of a string split.
+    /// </summary>
+    public ref struct SplitEnumerator
+    {
+        private readonly char _split;
+        private ReadOnlySpan<char> _str;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SplitEnumerator"/> struct.
+        /// </summary>
+        /// <param name="str">The string.</param>
+        /// <param name="split">The split char.</param>
+        public SplitEnumerator(ReadOnlySpan<char> str, char split)
+        {
+            _str = str;
+            _split = split;
+            Current = default;
+        }
+
+        /// <summary>
+        /// Gets this enumerator.
+        /// </summary>
+        /// <returns>This.</returns>
+        public SplitEnumerator GetEnumerator()
+            => this;
+
+        /// <summary>
+        /// Move to next line.
+        /// </summary>
+        /// <returns>Whether move was successful.</returns>
+        public bool MoveNext()
+        {
+            var span = _str;
+            if (span.Length == 0)
+            {
+                return false;
+            }
+
+            var index = span.IndexOf(_split);
+            if (index == -1)
+            {
+                _str = ReadOnlySpan<char>.Empty;
+                Current = span;
+                return true;
+            }
+
+            Current = span.Slice(0, index);
+            _str = span.Slice(index + 1);
+            return true;
+        }
+
+        /// <summary>
+        /// Current line.
+        /// </summary>
+        public ReadOnlySpan<char> Current { get; private set; }
+    }
+
+    /// <summary>
     /// An enumerator of a string lines.
     /// </summary>
     public ref struct LineSplitEnumerator

@@ 18,21 18,21 @@ public class ServerLoginCryptography : ICryptography
     {
         try
         {
-            string decryptedPacket = string.Empty;
+            StringBuilder decryptedPacket = new StringBuilder(str.Length);
 
             foreach (byte character in str)
             {
                 if (character > 14)
                 {
-                    decryptedPacket += Convert.ToChar((character - 15) ^ 195);
+                    decryptedPacket.Append(Convert.ToChar((character - 15) ^ 195));
                 }
                 else
                 {
-                    decryptedPacket += Convert.ToChar((256 - (15 - character)) ^ 195);
+                    decryptedPacket.Append(Convert.ToChar((256 - (15 - character)) ^ 195));
                 }
             }
 
-            return decryptedPacket;
+            return decryptedPacket.ToString();
         }
         catch
         {


@@ 46,7 46,7 @@ public class ServerLoginCryptography : ICryptography
         try
         {
             packet += " ";
-            byte[] tmp = Encoding.Default.GetBytes(packet);
+            byte[] tmp = encoding.GetBytes(packet);
             for (int i = 0; i < packet.Length; i++)
             {
                 tmp[i] = Convert.ToByte(tmp[i] + 15);

@@ 5,6 5,7 @@
 //  Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System.Text;
+using NosSmooth.Cryptography.Extensions;
 
 namespace NosSmooth.Cryptography;
 


@@ 63,71 64,47 @@ public class ServerWorldCryptography : ICryptography
 
     private static string DecryptAuthed(in ReadOnlySpan<byte> str, int encryptionKey, Encoding encoding)
     {
-        var encryptedString = new StringBuilder();
+        var encryptedString = new StringBuilder(str.Length);
 
         int sessionKey = encryptionKey & 0xFF;
         byte sessionNumber = unchecked((byte)(encryptionKey >> 6));
         sessionNumber &= 0xFF;
         sessionNumber &= 3;
 
+        byte firstbyte = unchecked((byte)(sessionKey + 0x40));
+
         switch (sessionNumber)
         {
             case 0:
-                foreach (byte character in str)
-                {
-                    byte firstbyte = unchecked((byte)(sessionKey + 0x40));
-                    byte highbyte = unchecked((byte)(character - firstbyte));
-                    encryptedString.Append((char)highbyte);
-                }
-
-                break;
-
             case 1:
                 foreach (byte character in str)
                 {
-                    byte firstbyte = unchecked((byte)(sessionKey + 0x40));
                     byte highbyte = unchecked((byte)(character + firstbyte));
                     encryptedString.Append((char)highbyte);
                 }
 
                 break;
-
             case 2:
-                foreach (byte character in str)
-                {
-                    byte firstbyte = unchecked((byte)(sessionKey + 0x40));
-                    byte highbyte = unchecked((byte)(character - firstbyte ^ 0xC3));
-                    encryptedString.Append((char)highbyte);
-                }
-
-                break;
-
             case 3:
                 foreach (byte character in str)
                 {
-                    byte firstbyte = unchecked((byte)(sessionKey + 0x40));
                     byte highbyte = unchecked((byte)(character + firstbyte ^ 0xC3));
                     encryptedString.Append((char)highbyte);
                 }
 
                 break;
-
             default:
                 encryptedString.Append((char)0xF);
                 break;
         }
 
-        string[] temp = encryptedString.ToString().Split((char)0xFF);
-
-        var save = new StringBuilder();
+        var temp = encryptedString.ToString().SplitAllocationless((char)0xFF);
+        var save = new StringBuilder(encryptedString.Length);
 
-        for (int i = 0; i < temp.Length; i++)
+        foreach (var packet in temp)
         {
-            save.Append(DecryptPrivate(temp[i].AsSpan(), encoding));
-            if (i < temp.Length - 2)
-            {
-                save.Append((char)'\n');
-            }
+            save.Append(DecryptPrivate(packet, encoding));
+            save.Append((char)'\n');
         }
 
         return save.ToString();


@@ 212,7 189,7 @@ public class ServerWorldCryptography : ICryptography
     {
         try
         {
-            var encryptedStringBuilder = new StringBuilder();
+            var encryptedStringBuilder = new StringBuilder(str.Length);
             for (int i = 1; i < str.Length; i++)
             {
                 if (Convert.ToChar(str[i]) == 0xE)


@@ 250,9 227,6 @@ public class ServerWorldCryptography : ICryptography
                 switch (firstbyte)
                 {
                     case 0:
-                        encryptedStringBuilder.Append(' ');
-                        break;
-
                     case 1:
                         encryptedStringBuilder.Append(' ');
                         break;