CRITICAL FIX: ERROR_HANDLE_EOF = 38 (raw Win32), not 0x80070026 (HRESULT). GetLastWin32Error returns raw codes. Rust windows-rs wraps as HRESULT which confused the original port.

FastSeekWpf/NativeInterop/Win32Api.cs

@@ -30,18 +30,12 @@ internal static class Win32Api
     public const uint OPEN_EXISTING = 3;
     public const uint FILE_FLAG_BACKUP_SEMANTICS = 0x02000000;
     public const uint FILE_FLAG_SEQUENTIAL_SCAN = 0x08000000;
-    public const uint FILE_FLAG_NO_BUFFERING = 0x20000000;
-    public const uint FILE_ATTRIBUTE_NORMAL = 0x00000080;
 
     // ── IOCTL codes ──
-    // CRITICAL: These must match the Windows SDK exactly. Previous versions had
-    // typos (0x900B03 instead of 0x900B3, 0x900F44 instead of 0x900F4) which
-    // caused DeviceIoControl to return ERROR_INVALID_FUNCTION.
-    // Verified against windows-rs crate and Windows SDK winioctl.h.
+    // From Windows SDK winioctl.h. Verified against windows-rs crate.
     public const uint FSCTL_ENUM_USN_DATA = 0x000900B3;
     public const uint FSCTL_QUERY_USN_JOURNAL = 0x000900F4;
     public const uint FSCTL_READ_USN_JOURNAL = 0x000900BB;
-    public const uint FSCTL_READ_FILE_USN_DATA = 0x000900EB;
 
     // USN reasons
     public const uint USN_REASON_FILE_CREATE = 0x00000100;
@@ -49,9 +43,12 @@ internal static class Win32Api
     public const uint USN_REASON_RENAME_OLD_NAME = 0x00001000;
     public const uint USN_REASON_RENAME_NEW_NAME = 0x00002000;
 
-    // Error codes
-    public const uint ERROR_HANDLE_EOF = 0x80070026;
-    public const uint ERROR_JOURNAL_NOT_ACTIVE = 1179;
+    // Win32 error codes (raw, NOT HRESULT)
+    // Marshal.GetLastWin32Error() returns these raw codes.
+    // Rust windows-rs wraps them as HRESULT (0x8007XXXX).
+    public const int ERROR_HANDLE_EOF = 38;               // Raw: 0x26
+    public const int ERROR_INSUFFICIENT_BUFFER = 122;    // Raw: 0x7A
+    public const int ERROR_JOURNAL_NOT_ACTIVE = 1179;    // Raw: 0x49B
 
     // DWM
     public const int DWMWA_WINDOW_CORNER_PREFERENCE = 33;
@@ -77,7 +74,7 @@ internal static class Win32Api
         out uint lpNumberOfBytesRead,
         IntPtr lpOverlapped);
 
-    // Unsafe overload: read into a byte[] at a given offset via GCHandle
+    // Unsafe overload: read into a byte[] at a given offset — matches Rust ReadFile into &mut buffer[leftover..]
     public static unsafe bool ReadFile(
         IntPtr hFile,
         byte[] lpBuffer,