From f79cd759bd722e9ab1a62ab70a0e2681911fd991 Mon Sep 17 00:00:00 2001
From: Matt Nadareski <mnadareski@outlook.com>
Date: Wed, 14 Dec 2022 23:16:37 -0800
Subject: [PATCH] Add SFFS models, no encryption

---
 BurnOutSharp.Models/SFFS/FileEntry.cs         | 20 +++++++++++
 BurnOutSharp.Models/SFFS/FileHeader.cs        | 20 +++++++++++
 BurnOutSharp.Models/SFFS/Header.cs            | 29 ++++++++++++++++
 .../SFFS/StarForceFileSystem.cs               | 33 +++++++++++++++++++
 4 files changed, 102 insertions(+)
 create mode 100644 BurnOutSharp.Models/SFFS/FileEntry.cs
 create mode 100644 BurnOutSharp.Models/SFFS/FileHeader.cs
 create mode 100644 BurnOutSharp.Models/SFFS/Header.cs
 create mode 100644 BurnOutSharp.Models/SFFS/StarForceFileSystem.cs

diff --git a/BurnOutSharp.Models/SFFS/FileEntry.cs b/BurnOutSharp.Models/SFFS/FileEntry.cs
new file mode 100644
index 00000000..3f774bc7
--- /dev/null
+++ b/BurnOutSharp.Models/SFFS/FileEntry.cs
@@ -0,0 +1,20 @@
+using System.Runtime.InteropServices;
+
+namespace BurnOutSharp.Models.SFFS
+{
+    /// <see cref="https://forum.xentax.com/viewtopic.php?f=21&t=2084"/>
+    [StructLayout(LayoutKind.Sequential)]
+    public class FileEntry
+    {
+        /// <summary>
+        /// MD5 hash of filename (not encrypted,)
+        /// </summary>
+        /// <remarks>0x10 bytes</remarks>
+        public byte[] FilenameMD5Hash;
+
+        /// <summary>
+        /// Index of fileheader (encrypted with filename)
+        /// </summary>
+        public ulong FileHeaderIndex;
+    }
+}
diff --git a/BurnOutSharp.Models/SFFS/FileHeader.cs b/BurnOutSharp.Models/SFFS/FileHeader.cs
new file mode 100644
index 00000000..5cbff9fa
--- /dev/null
+++ b/BurnOutSharp.Models/SFFS/FileHeader.cs
@@ -0,0 +1,20 @@
+using System.Runtime.InteropServices;
+
+namespace BurnOutSharp.Models.SFFS
+{
+    /// <see cref="https://forum.xentax.com/viewtopic.php?f=21&t=2084"/>
+    [StructLayout(LayoutKind.Sequential)]
+    public class FileHeader
+    {
+        /// <summary>
+        /// Start of file content (encrypted with filename)
+        /// </summary>
+        public ulong FileContentStart;
+
+        /// <summary>
+        /// File info (timestamps, size, data position, encrypted)
+        /// </summary>
+        /// <remarks>Unknown format</remarks>
+        public byte[] FileInfo;
+    }
+}
diff --git a/BurnOutSharp.Models/SFFS/Header.cs b/BurnOutSharp.Models/SFFS/Header.cs
new file mode 100644
index 00000000..57354bf8
--- /dev/null
+++ b/BurnOutSharp.Models/SFFS/Header.cs
@@ -0,0 +1,29 @@
+using System.Runtime.InteropServices;
+
+namespace BurnOutSharp.Models.SFFS
+{
+    /// <summary>
+    /// Header
+    /// </summary>
+    /// <see cref="https://forum.xentax.com/viewtopic.php?f=21&t=2084"/>
+    [StructLayout(LayoutKind.Sequential)]
+    public class Header
+    {
+        /// <summary>
+        /// "SFFS"
+        /// </summary>
+        public uint Magic;
+
+        /// <summary>
+        /// Version (0x00000001)
+        /// </summary>
+        public uint Version;
+
+        /// <summary>
+        /// Number of files in the container (encrypted with application key).
+        /// Minimal number here is usually 65h, so its not real file count
+        /// in some cases, more like index size
+        /// </summary>
+        public ulong FileCount;
+    }
+}
diff --git a/BurnOutSharp.Models/SFFS/StarForceFileSystem.cs b/BurnOutSharp.Models/SFFS/StarForceFileSystem.cs
new file mode 100644
index 00000000..ec491584
--- /dev/null
+++ b/BurnOutSharp.Models/SFFS/StarForceFileSystem.cs
@@ -0,0 +1,33 @@
+namespace BurnOutSharp.Models.SFFS
+{
+    /// <summary>
+    /// SFFS consists of 2 major parts: the container files that contain the game
+    /// content and a filesystem filter driver (sfvfs02.sys) that handles all file-io.
+    /// When a game has SFFS'ed files and uses some file-io api like CreateFile, the
+    /// SFFS filterdriver sees this request and handles it if needed.that way, SFFS is
+    /// totally transparent to the game, since it never knows if the data is coming from
+    /// real file API or from the SFFS filterdriver. during SF initialization, the
+    /// SF-process registers itself as a SFFS process in a processid list, maintained
+    /// from the filterdriver. Part of that registration are the names of the
+    /// containerfiles, the process uses and an application key, that is needed to
+    /// decrypt headerinfos. Note that SFFS itself is completly vm-free.
+    /// </summary>
+    /// <see cref="https://forum.xentax.com/viewtopic.php?f=21&t=2084"/>
+    public class StarForceFileSystem
+    {
+        /// <summary>
+        /// Header
+        /// </summary>
+        public Header Header { get; set; }
+
+        /// <summary>
+        /// Files
+        /// </summary>
+        public FileEntry[] Files { get; set; }
+
+        /// <summary>
+        /// File headers
+        /// </summary>
+        public FileHeader[] FileHeaders { get; set; }
+    }
+}