Added test project for vfs

- Added test case for: decode_fat_timestamp
- Changed location of: decode_fat_timestamp

src/xenia/vfs/devices/stfs_xbox.h

@@ -10,12 +10,38 @@
 #ifndef XENIA_VFS_DEVICES_STFS_XBOX_H_
 #define XENIA_VFS_DEVICES_STFS_XBOX_H_
 
+#include "xenia/xbox.h"
 #include "xenia/base/string_util.h"
 #include "xenia/kernel/util/xex2_info.h"
 
 namespace xe {
 namespace vfs {
 
+// Convert FAT timestamp to 100-nanosecond intervals since January 1, 1601 (UTC)
+inline uint64_t decode_fat_timestamp(const uint32_t date, const uint32_t time) {
+  struct tm tm = {0};
+  // 80 is the difference between 1980 (FAT) and 1900 (tm);
+  tm.tm_year = ((0xFE00 & date) >> 9) + 80;
+  tm.tm_mon = ((0x01E0 & date) >> 5);
+  tm.tm_mday = (0x001F & date) >> 0;
+  tm.tm_hour = (0xF800 & time) >> 11;
+  tm.tm_min = (0x07E0 & time) >> 5;
+  tm.tm_sec = (0x001F & time) << 1;  // the value stored in 2-seconds intervals
+  tm.tm_isdst = 0;
+
+  #if XE_PLATFORM_WIN32
+  time_t timet = _mkgmtime(&tm);
+#else
+  time_t timet = timegm(&tm);
+#endif
+
+  if (timet == -1) {
+    return 0;
+  }
+  // 11644473600LL is a difference between 1970 and 1601
+  return (timet + 11644473600LL) * 10000000;
+}
+
 // Structs used for interchange between Xenia and actual Xbox360 kernel/XAM
 
 inline uint32_t load_uint24_be(const uint8_t* p) {