Fix change_times on Windows and simplify time handling in stat

core/os/os2/file_windows.odin

@@ -813,19 +813,11 @@ _chtimes :: proc(name: string, atime, mtime: time.Time) -> Error {
 	defer close(f)
 	return _fchtimes(f, atime, mtime)
 }
+
 _fchtimes :: proc(f: ^File, atime, mtime: time.Time) -> Error {
 	if f == nil || f.impl == nil {
 		return nil
 	}
-	d: win32.BY_HANDLE_FILE_INFORMATION
-	if !win32.GetFileInformationByHandle(_handle(f), &d) {
-		return _get_platform_error()
-	}
-
-	to_windows_time :: #force_inline proc(t: time.Time) -> win32.LARGE_INTEGER {
-		// a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC)
-		return win32.LARGE_INTEGER(time.time_to_unix_nano(t) * 100 + 116444736000000000)
-	}
 
 	atime, mtime := atime, mtime
 	if time.time_to_unix_nano(atime) < time.time_to_unix_nano(mtime) {
@@ -833,9 +825,9 @@ _fchtimes :: proc(f: ^File, atime, mtime: time.Time) -> Error {
 	}
 
 	info: win32.FILE_BASIC_INFO
-	info.LastAccessTime = to_windows_time(atime)
-	info.LastWriteTime  = to_windows_time(mtime)
-	if !win32.SetFileInformationByHandle(_handle(f), .FileBasicInfo, &info, size_of(d)) {
+	info.LastAccessTime = time_as_filetime(atime)
+	info.LastWriteTime  = time_as_filetime(mtime)
+	if !win32.SetFileInformationByHandle(_handle(f), .FileBasicInfo, &info, size_of(info)) {
 		return _get_platform_error()
 	}
 	return nil

core/os/os2/stat_windows.odin

@@ -239,14 +239,30 @@ _file_type_mode_from_file_attributes :: proc(file_attributes: win32.DWORD, h: wi
 	return
 }
 
+// a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC)
+time_as_filetime :: #force_inline proc(t: time.Time) -> (ft: win32.LARGE_INTEGER) {
+	win := u64(t._nsec / 100) + 116444736000000000
+	return win32.LARGE_INTEGER(win)
+}
+
+filetime_as_time_li :: #force_inline proc(ft: win32.LARGE_INTEGER) -> (t: time.Time) {
+	return {_nsec=(i64(ft) - 116444736000000000) * 100}
+}
+
+filetime_as_time_ft :: #force_inline proc(ft: win32.FILETIME) -> (t: time.Time) {
+	return filetime_as_time_li(win32.LARGE_INTEGER(ft.dwLowDateTime) + win32.LARGE_INTEGER(ft.dwHighDateTime) << 32)
+}
+
+filetime_as_time :: proc{filetime_as_time_ft, filetime_as_time_li}
+
 _file_info_from_win32_file_attribute_data :: proc(d: ^win32.WIN32_FILE_ATTRIBUTE_DATA, name: string, allocator: runtime.Allocator) -> (fi: File_Info, e: Error) {
 	fi.size = i64(d.nFileSizeHigh)<<32 + i64(d.nFileSizeLow)
 	type, mode := _file_type_mode_from_file_attributes(d.dwFileAttributes, nil, 0)
 	fi.type = type
 	fi.mode |= mode
-	fi.creation_time     = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftCreationTime))
-	fi.modification_time = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftLastWriteTime))
-	fi.access_time       = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftLastAccessTime))
+	fi.creation_time     = filetime_as_time(d.ftCreationTime)
+	fi.modification_time = filetime_as_time(d.ftLastWriteTime)
+	fi.access_time       = filetime_as_time(d.ftLastAccessTime)
 	fi.fullpath, e = full_path_from_name(name, allocator)
 	fi.name = basename(fi.fullpath)
 	return
@@ -257,9 +273,9 @@ _file_info_from_win32_find_data :: proc(d: ^win32.WIN32_FIND_DATAW, name: string
 	type, mode := _file_type_mode_from_file_attributes(d.dwFileAttributes, nil, 0)
 	fi.type = type
 	fi.mode |= mode
-	fi.creation_time     = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftCreationTime))
-	fi.modification_time = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftLastWriteTime))
-	fi.access_time       = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftLastAccessTime))
+	fi.creation_time     = filetime_as_time(d.ftCreationTime)
+	fi.modification_time = filetime_as_time(d.ftLastWriteTime)
+	fi.access_time       = filetime_as_time(d.ftLastAccessTime)
 	fi.fullpath, e = full_path_from_name(name, allocator)
 	fi.name = basename(fi.fullpath)
 	return
@@ -289,9 +305,9 @@ _file_info_from_get_file_information_by_handle :: proc(path: string, h: win32.HA
 	type, mode := _file_type_mode_from_file_attributes(d.dwFileAttributes, h, 0)
 	fi.type = type
 	fi.mode |= mode
-	fi.creation_time     = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftCreationTime))
-	fi.modification_time = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftLastWriteTime))
-	fi.access_time       = time.unix(0, win32.FILETIME_as_unix_nanoseconds(d.ftLastAccessTime))
+	fi.creation_time     = filetime_as_time(d.ftCreationTime)
+	fi.modification_time = filetime_as_time(d.ftLastWriteTime)
+	fi.access_time       = filetime_as_time(d.ftLastAccessTime)
 	return fi, nil
 }