Added Game Sync ID (de)obfuscation algorithm.

library/Library.csproj

@@ -115,6 +115,7 @@
     <Compile Include="Support\AssertHelper.cs" />
     <Compile Include="Support\EncodedString4.cs" />
     <Compile Include="Support\EncodedString5.cs" />
+    <Compile Include="Support\GameSyncUtils.cs" />
     <Compile Include="Support\Indexer1d.cs" />
     <Compile Include="Support\LazyKeyValuePair.cs" />
     <Compile Include="Support\LocalizedString.cs" />

library/Support/GameSyncUtils.cs

@@ -0,0 +1,98 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace PkmnFoundations.Support
+{
+    public static class GameSyncUtils
+    {
+		private static ushort GameSyncCrc16(int val)
+        {
+			var table = new ushort[]
+			{
+				// xxx: I suspect this lut is actually a baked crc polynomial
+				0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
+				0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
+				0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
+				0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
+				0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
+				0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
+				0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
+				0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
+				0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
+				0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
+				0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
+				0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
+				0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
+				0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
+				0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
+				0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
+				0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
+				0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
+				0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
+				0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
+				0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
+				0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
+				0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
+				0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
+				0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
+				0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
+				0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
+				0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
+				0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
+				0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
+				0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
+				0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
+			};
+
+			int crc16 = 0xffff;
+
+			for (int i = 0; i < 4; i++)
+            {
+				crc16 = (crc16 << 8) ^ table[((crc16 >> 8) ^ (val & 0xff)) & 0xff];
+				val >>= 8;
+            }
+
+			return (ushort)crc16;
+        }
+
+		public static string PidToGsid(int pid)
+        {
+			return Base32Encode((long)pid | ((long)GameSyncCrc16(pid) << 32));
+        }
+
+		public static int GsidToPid(string gsid)
+        {
+			return (int)Base32Decode(gsid);
+        }
+
+		private const string charset = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"; // Not the entire alphabet, be careful
+		public static string Base32Encode(long value)
+		{
+			StringBuilder result = new StringBuilder(10);
+
+			for (int i = 0; i < 10; i++)
+			{
+				result.Append(charset[(int)(value & 0x1f)]);
+				value >>= 5;
+			}
+			return result.ToString();
+		}
+
+		public static long Base32Decode(string value)
+        {
+			long result = 0;
+
+			// xxx: we don't need to reverse this if we shift the other way and fill in starting at the MSB
+			foreach (char c in value.ToUpperInvariant().Reverse())
+            {
+				result <<= 5;
+				if (charset.Contains(c)) result |= (long)charset.IndexOf(c);
+				else throw new FormatException("Base32 string contains invalid characters");
+			}
+			return result;
+		}
+
+	}
+}

web/src/Common.cs

@@ -62,6 +62,11 @@ namespace PkmnFoundations.Web
             }
         }
 
+        public static string FormatReturns(string text, string ending)
+        {
+            return text.Replace("\r\n", "\n").Replace("\r", "\n").Replace("\n", ending);
+        }
+
         private static byte[] m_pad = null;
 
         /// <summary>

web/test/Gsid.aspx

@@ -0,0 +1,12 @@
+<%@ Page Title="" Language="C#" MasterPageFile="~/masters/MasterPage.master" AutoEventWireup="true" CodeBehind="Gsid.aspx.cs" Inherits="PkmnFoundations.Web.test.Gsid" %>
+<%@ Register TagPrefix="pf" Namespace="PkmnFoundations.Web" Assembly="PkmnFoundations.Web" %>
+
+<asp:Content ID="Content1" ContentPlaceHolderID="cpHead" runat="server">
+    <pf:HeaderColour ID="HeaderColour1" CssClass="test" runat="server" />
+</asp:Content>
+
+<asp:Content ID="Content2" ContentPlaceHolderID="cpMain" runat="server">
+
+    <asp:Literal ID="litOutput" runat="server" />
+
+</asp:Content>

web/test/Gsid.aspx.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Web;
+using System.Web.UI;
+using System.Web.UI.WebControls;
+using PkmnFoundations.Support;
+
+namespace PkmnFoundations.Web.test
+{
+    public partial class Gsid : System.Web.UI.Page
+    {
+        protected void Page_Load(object sender, EventArgs e)
+        {
+            StringBuilder output = new StringBuilder();
+            var gsids = new int[] { 476518182, 330241374 };
+            foreach (var gsid in gsids)
+            {
+                string enc = GameSyncUtils.PidToGsid(gsid);
+                int dec = (int)GameSyncUtils.GsidToPid(enc);
+                output.AppendLine(enc);
+                output.AppendLine(dec.ToString());
+                output.AppendLine(String.Format("{0} ({0:X8}) == {1} ({1:X8})? {2}", gsid, dec, gsid == dec));
+                output.AppendLine();
+            }
+
+            litOutput.Text = Common.FormatReturns(Common.HtmlEncode(output.ToString()), "<br />\n");
+        }
+    }
+}

web/test/Gsid.aspx.designer.cs

@@ -0,0 +1,35 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated. 
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace PkmnFoundations.Web.test
+{
+
+
+    public partial class Gsid
+    {
+
+        /// <summary>
+        /// HeaderColour1 control.
+        /// </summary>
+        /// <remarks>
+        /// Auto-generated field.
+        /// To modify move field declaration from designer file to code-behind file.
+        /// </remarks>
+        protected global::PkmnFoundations.Web.HeaderColour HeaderColour1;
+
+        /// <summary>
+        /// litOutput control.
+        /// </summary>
+        /// <remarks>
+        /// Auto-generated field.
+        /// To modify move field declaration from designer file to code-behind file.
+        /// </remarks>
+        protected global::System.Web.UI.WebControls.Literal litOutput;
+    }
+}

web/web.csproj

@@ -3628,6 +3628,7 @@
     <Content Include="scripts\retina.js" />
     <Content Include="test\BoxUp.aspx" />
     <Content Include="test\Decode.aspx" />
+    <Content Include="test\Gsid.aspx" />
     <Content Include="test\NameDecode.aspx" />
     <Content Include="test\NameEncode.aspx" />
     <Content Include="test\VideoId.aspx" />
@@ -3793,6 +3794,13 @@
     <Compile Include="test\Decode.aspx.designer.cs">
       <DependentUpon>Decode.aspx</DependentUpon>
     </Compile>
+    <Compile Include="test\Gsid.aspx.cs">
+      <DependentUpon>Gsid.aspx</DependentUpon>
+      <SubType>ASPXCodeBehind</SubType>
+    </Compile>
+    <Compile Include="test\Gsid.aspx.designer.cs">
+      <DependentUpon>Gsid.aspx</DependentUpon>
+    </Compile>
     <Compile Include="test\NameDecode.aspx.cs">
       <DependentUpon>NameDecode.aspx</DependentUpon>
       <SubType>ASPXCodeBehind</SubType>