Upload FastSeekWpf/Core/MftReader.cs

FastSeekWpf/Core/MftReader.cs

@@ -9,7 +9,6 @@ namespace FastSeekWpf.Core;
 
 public class MftReader : IDisposable
 {
-    // Volume handle — used for boot sector read and FSCTL fallback
     private readonly IntPtr _volumeHandle;
     private readonly NtfsDrive _drive;
     private bool _disposed;
@@ -38,12 +37,8 @@ public class MftReader : IDisposable
         }
     }
 
-    // ------------------------------------------------------------------
-    //  Primary: direct $MFT file read  (falls back to FSCTL if fails)
-    // ------------------------------------------------------------------
-
     /// <summary>
-    /// Read $MFT file directly for maximum speed. Returns null if unavailable.
+    /// Primary: direct $MFT file read. Returns null if unavailable.
     /// Matches Rust scan_direct() exactly.
     /// </summary>
     public ScanResult? ScanDirect()
@@ -53,7 +48,7 @@ public class MftReader : IDisposable
 
         string mftPath = $"{_drive.Root}$MFT";
 
-        // Open the $MFT file as a normal file (not the volume device)
+        // Open $MFT as a normal file (not the volume device)
         IntPtr mftHandle = Win32Api.CreateFileW(
             mftPath,
             Win32Api.GENERIC_READ,
@@ -76,8 +71,10 @@ public class MftReader : IDisposable
 
             while (true)
             {
+                // CRITICAL: read into buffer starting at 'leftover', not at 0
+                // This matches Rust: ReadFile(mft_handle, &mut buffer[leftover..])
                 bool ok = Win32Api.ReadFile(
-                    mftHandle, buffer, (uint)(buffer.Length - leftover), out uint bytesRead, IntPtr.Zero);
+                    mftHandle, buffer, leftover, (uint)(buffer.Length - leftover), out uint bytesRead, IntPtr.Zero);
                 if (!ok || bytesRead == 0)
                     break;
 
@@ -113,10 +110,9 @@ public class MftReader : IDisposable
         }
     }
 
-    // ------------------------------------------------------------------
-    //  Fallback: FSCTL_ENUM_USN_DATA (4 MB buffer)
-    // ------------------------------------------------------------------
-
+    /// <summary>
+    /// Fallback: FSCTL_ENUM_USN_DATA (4 MB buffer)
+    /// </summary>
     public ScanResult Scan()
     {
         var records = new List<CompactRecord>();
@@ -228,13 +224,8 @@ public class MftReader : IDisposable
     //  NTFS helpers
     // ------------------------------------------------------------------
 
-    /// <summary>
-    /// Read MFT record size from NTFS boot sector via volume handle.
-    /// Matches Rust read_mft_record_size().
-    /// </summary>
     private int? ReadMftRecordSize()
     {
-        // Seek to beginning of volume
         Win32Api.SetFilePointerEx(_volumeHandle, 0, out _, 0);
 
         byte[] boot = new byte[512];
@@ -257,8 +248,7 @@ public class MftReader : IDisposable
     }
 
     /// <summary>
-    /// Apply NTFS multi-sector fixup. Returns false if record is invalid.
-    /// CRITICAL: Restores the original bytes from the fixup array back to sector ends.
+    /// Apply NTFS multi-sector fixup. RESTORES bytes from fixup array.
     /// Matches Rust apply_fixup() exactly.
     /// </summary>
     private static bool ApplyFixup(byte[] record, int offset, int recordSize)
@@ -293,8 +283,7 @@ public class MftReader : IDisposable
     }
 
     /// <summary>
-    /// Parse one MFT FILE record, extracting name + parent into the arena.
-    /// Matches Rust parse_file_record() exactly.
+    /// Parse one MFT FILE record. Matches Rust parse_file_record() exactly.
     /// </summary>
     private static void ParseFileRecord(
         ReadOnlySpan<byte> record,