From 397f5e54e0472b0f2e348dcdb648adfbeef8ba3a Mon Sep 17 00:00:00 2001
From: Pierre Bourdon <delroth@gmail.com>
Date: Sun, 6 Aug 2017 22:19:08 +0200
Subject: [PATCH] WFS: Implement READ_ABSOLUTE (merged with READ
 implementation).

---
 Source/Core/Core/IOS/WFS/WFSSRV.cpp | 25 +++++++++++++++++++------
 Source/Core/Core/IOS/WFS/WFSSRV.h   |  1 +
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/Source/Core/Core/IOS/WFS/WFSSRV.cpp b/Source/Core/Core/IOS/WFS/WFSSRV.cpp
index a2601f3422..0a76d6e482 100644
--- a/Source/Core/Core/IOS/WFS/WFSSRV.cpp
+++ b/Source/Core/Core/IOS/WFS/WFSSRV.cpp
@@ -189,26 +189,39 @@ IPCCommandResult WFSSRV::IOCtl(const IOCtlRequest& request)
   }
 
   case IOCTL_WFS_READ:
+  case IOCTL_WFS_READ_ABSOLUTE:
   {
     u32 addr = Memory::Read_U32(request.buffer_in);
+    u32 position = Memory::Read_U32(request.buffer_in + 4);  // Only for absolute.
     u16 fd = Memory::Read_U16(request.buffer_in + 0xC);
     u32 size = Memory::Read_U32(request.buffer_in + 8);
 
+    bool absolute = request.request == IOCTL_WFS_READ_ABSOLUTE;
+
     FileDescriptor* fd_obj = FindFileDescriptor(fd);
     if (fd_obj == nullptr)
     {
       ERROR_LOG(IOS, "IOCTL_WFS_READ: invalid file descriptor %d", fd);
-      return_error_code = -1;  // TODO(wfs): proper error code.
+      return_error_code = WFS_EBADFD;
       break;
     }
 
-    size_t read_bytes;
-    if (!fd_obj->file.ReadArray(Memory::GetPointer(addr), size, &read_bytes))
+    u64 previous_position = fd_obj->file.Tell();
+    if (absolute)
     {
-      return_error_code = -1;  // TODO(wfs): proper error code.
-      break;
+      fd_obj->file.Seek(position, SEEK_SET);
+    }
+    size_t read_bytes;
+    fd_obj->file.ReadArray(Memory::GetPointer(addr), size, &read_bytes);
+    // TODO(wfs): Handle read errors.
+    if (absolute)
+    {
+      fd_obj->file.Seek(previous_position, SEEK_SET);
+    }
+    else
+    {
+      fd_obj->position += read_bytes;
     }
-    fd_obj->position += read_bytes;
 
     INFO_LOG(IOS, "IOCTL_WFS_READ: read %zd bytes from FD %d (%s)", read_bytes, fd,
              fd_obj->path.c_str());
diff --git a/Source/Core/Core/IOS/WFS/WFSSRV.h b/Source/Core/Core/IOS/WFS/WFSSRV.h
index 72b051f87a..cba30037a1 100644
--- a/Source/Core/Core/IOS/WFS/WFSSRV.h
+++ b/Source/Core/Core/IOS/WFS/WFSSRV.h
@@ -67,6 +67,7 @@ private:
     IOCTL_WFS_WRITE = 0x22,
     IOCTL_WFS_ATTACH_DETACH = 0x2d,
     IOCTL_WFS_ATTACH_DETACH_2 = 0x2e,
+    IOCTL_WFS_READ_ABSOLUTE = 0x48,
   };
 
   enum