From e8d59f9c2b51859f214a84a47583e0fae5aab5b8 Mon Sep 17 00:00:00 2001
From: Kae <80987908+Novaenia@users.noreply.github.com>
Date: Thu, 12 Sep 2024 23:06:13 +1000
Subject: fix windows pread and pwrite bug

reading without a byte offset specified can affect absolute reads afterward, this is a workaround (thanks windows...)
---
 source/core/StarFile_windows.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'source/core/StarFile_windows.cpp')

diff --git a/source/core/StarFile_windows.cpp b/source/core/StarFile_windows.cpp
index 0b5c286..d9719b1 100644
--- a/source/core/StarFile_windows.cpp
+++ b/source/core/StarFile_windows.cpp
@@ -377,7 +377,12 @@ size_t File::pread(void* f, char* data, size_t len, StreamOffset position) {
   HANDLE file = (HANDLE)f;
   DWORD numRead = 0;
   OVERLAPPED overlapped = makeOverlapped(position);
+
+  StreamOffset pos = ftell(f);
+  if (pos != 0) fseek(f, 0, IOSeek::Absolute);
   int ret = ReadFile(file, data, len, &numRead, &overlapped);
+  if (pos != 0) fseek(f, pos, IOSeek::Absolute);
+
   if (ret == 0) {
     auto err = GetLastError();
     if (err != ERROR_IO_PENDING)
@@ -391,7 +396,12 @@ size_t File::pwrite(void* f, char const* data, size_t len, StreamOffset position
   HANDLE file = (HANDLE)f;
   DWORD numWritten = 0;
   OVERLAPPED overlapped = makeOverlapped(position);
+
+  StreamOffset pos = ftell(f);
+  if (pos != 0) fseek(f, 0, IOSeek::Absolute);
   int ret = WriteFile(file, data, len, &numWritten, &overlapped);
+  if (pos != 0) fseek(f, pos, IOSeek::Absolute);
+
   if (ret == 0) {
     auto err = GetLastError();
     if (err != ERROR_IO_PENDING)
-- 
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