From 629637d95e066dcef22510f1c151f0405e81e499 Mon Sep 17 00:00:00 2001
From: Leonid Yuriev <leo@yuriev.ru>
Date: Sun, 4 Nov 2018 18:57:08 +0300
Subject: [PATCH] mdbx-osal: add mdbx_fseek().

Change-Id: I5744aa3ba51bd1acaeedd866e6b21a1330c3f711
---
 src/osal.c | 13 +++++++++++++
 src/osal.h |  1 +
 2 files changed, 14 insertions(+)

diff --git a/src/osal.c b/src/osal.c
index 4bb70d92..4f9aad27 100644
--- a/src/osal.c
+++ b/src/osal.c
@@ -753,6 +753,19 @@ int mdbx_ftruncate(mdbx_filehandle_t fd, uint64_t length) {
 #endif
 }
 
+int mdbx_fseek(mdbx_filehandle_t fd, uint64_t pos) {
+#if defined(_WIN32) || defined(_WIN64)
+  LARGE_INTEGER li;
+  li.QuadPart = pos;
+  return SetFilePointerEx(fd, li, NULL, FILE_BEGIN) ? MDBX_SUCCESS
+                                                    : GetLastError();
+#else
+  STATIC_ASSERT_MSG(sizeof(off_t) >= sizeof(size_t),
+                    "libmdbx requires 64-bit file I/O on 64-bit systems");
+  return (lseek(fd, pos, SEEK_SET) < 0) ? errno : MDBX_SUCCESS;
+#endif
+}
+
 /*----------------------------------------------------------------------------*/
 
 int mdbx_thread_create(mdbx_thread_t *thread,
diff --git a/src/osal.h b/src/osal.h
index 50416d96..9f9d1a44 100644
--- a/src/osal.h
+++ b/src/osal.h
@@ -504,6 +504,7 @@ int mdbx_thread_join(mdbx_thread_t thread);
 int mdbx_filesync(mdbx_filehandle_t fd, bool fullsync);
 int mdbx_filesize_sync(mdbx_filehandle_t fd);
 int mdbx_ftruncate(mdbx_filehandle_t fd, uint64_t length);
+int mdbx_fseek(mdbx_filehandle_t fd, uint64_t pos);
 int mdbx_filesize(mdbx_filehandle_t fd, uint64_t *length);
 int mdbx_openfile(const char *pathname, int flags, mode_t mode,
                   mdbx_filehandle_t *fd, bool exclusive);