support for macos save files

Author: Delynith

GeometryDashAPI/Crypt.cs

@@ -1,12 +1,23 @@
 using System.IO;
 using System.IO.Compression;
+using System.Security.Cryptography;
 using System.Text;
 using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
 
 namespace GeometryDashAPI
 {
     public class Crypt
     {
+        // The MacOS save file is not encoded like the Windows one - instead, it uses AES ECB encryption.
+        // Huge thanks to: https://github.com/qimiko/gd-save-tools/blob/b5176eb2c805ca65da3e51701409b72b90bdd497/assets/js/savefile.mjs#L43
+        private static byte[] MAC_SAVE_KEY =
+        [
+            0x69, 0x70, 0x75, 0x39, 0x54, 0x55, 0x76, 0x35,
+            0x34, 0x79, 0x76, 0x5D, 0x69, 0x73, 0x46, 0x4D,
+            0x68, 0x35, 0x40, 0x3B, 0x74, 0x2E, 0x35, 0x77,
+            0x33, 0x34, 0x45, 0x32, 0x52, 0x79, 0x40, 0x7B
+        ];
+        
         public static byte[] XOR(byte[] data, int key)
         {
             var result = new byte[data.Length];
@@ -53,5 +64,50 @@ public static byte[] GZipCompress(byte[] data)
             }
             return memory.ToArray();
         }
+        
+        public static byte[] SavingSaveAsMacOS(byte[] data)
+        {
+            using (Aes aesAlg = Aes.Create())
+            {
+                aesAlg.Key = MAC_SAVE_KEY;
+                aesAlg.Mode = CipherMode.ECB; 
+
+                ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
+
+                using (MemoryStream msEncrypt = new MemoryStream())
+                {
+                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
+                    {
+                        csEncrypt.Write(data, 0, data.Length);
+                    }
+                    return msEncrypt.ToArray();
+                }
+            }
+        }
+        
+        public static string LoadSaveAsMacOS(byte[] data)
+        {
+            using (Aes aesAlg = Aes.Create())
+            {
+                aesAlg.Key = MAC_SAVE_KEY;
+                aesAlg.Mode = CipherMode.ECB; 
+
+                // Create a decryptor to perform the stream transform.
+                ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
+
+                // Create the streams used for decryption.
+                using (MemoryStream msDecrypt = new MemoryStream(data))
+                {
+                    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
+                    {
+                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))
+                        {
+                            // Read the decrypted bytes from the decrypting stream and place them in a string.
+                            return srDecrypt.ReadToEnd();
+                        }
+                    }
+                }
+            }
+        }
     }
 }

GeometryDashAPI/Data/GameData.cs

@@ -36,11 +36,20 @@ public virtual async Task LoadAsync(string fileName)
             var data = new byte[file.Length];
             await file.ReadAsync(data, 0, data.Length);
 
-            var xor = Crypt.XOR(data, 0xB);
-            var index = xor.AsSpan().IndexOf((byte)0);
-            var gZipDecompress = Crypt.GZipDecompress(GameConvert.FromBase64(Encoding.ASCII.GetString(xor, 0, index >= 0 ? index : xor.Length)));
-
-            DataPlist = new Plist(Encoding.ASCII.GetBytes(gZipDecompress));
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                string decryptedData = Crypt.LoadSaveAsMacOS(data);
+                DataPlist = new Plist(Encoding.ASCII.GetBytes(decryptedData));
+            }
+            else
+            {
+                var xor = Crypt.XOR(data, 0xB);
+                var index = xor.AsSpan().IndexOf((byte)0);
+                var gZipDecompress =
+                    Crypt.GZipDecompress(
+                        GameConvert.FromBase64(Encoding.ASCII.GetString(xor, 0, index >= 0 ? index : xor.Length)));
+                DataPlist = new Plist(Encoding.ASCII.GetBytes(gZipDecompress));
+            }
         }
 
         /// <summary>
@@ -83,13 +92,22 @@ public static string ResolveFileName(GameDataType? type)
                 throw new InvalidOperationException("can't resolve the directory with the saves for undefined file type. Use certain file name");
             if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                 return $@"{Environment.GetEnvironmentVariable("LocalAppData")}\GeometryDash\CC{type}.dat";
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                return $@"/Users/{Environment.GetEnvironmentVariable("USER")}/Library/Application Support/GeometryDash/CC{type}.dat";
             throw new InvalidOperationException($"can't resolve the directory with the saves on your operating system: '{RuntimeInformation.OSDescription}'. Use certain file name");
         }
 
         private static byte[] GetFileContent(MemoryStream memory)
         {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                var encrypted = Crypt.SavingSaveAsMacOS(memory.ToArray());
+                return encrypted;
+            }
+
             var base64 = GameConvert.ToBase64(Crypt.GZipCompress(memory.ToArray()));
             return Crypt.XOR(Encoding.ASCII.GetBytes(base64), 0xB);
+
         }
     }
 }