Use aligned 64-bit arithmetic for FILETIME

It is not safe/performant to cast a FILETIME to a 64-bit integer,
however in virtually all instances what is wanted is the 64-bit integer.
Use a union to allow punning between a FILETIME and ULONGLONG, avoiding
copying.

3 files changed, 23 insertions, 35 deletions

diff --git a/otherlibs/unix/gettimeofday_win32.c b/otherlibs/unix/gettimeofday_win32.c
index ca6c91a4d3..4ba4a8a6a6 100644
--- a/otherlibs/unix/gettimeofday_win32.c
+++ b/otherlibs/unix/gettimeofday_win32.c
@@ -17,17 +17,17 @@
 #include <caml/alloc.h>
 #include <time.h>
 
+#define CAML_INTERNALS
+#include <caml/winsupport.h>
+
 #include "unixsupport.h"
 
 double caml_unix_gettimeofday_unboxed(value unit)
 {
-  FILETIME ft;
+  CAML_ULONGLONG_FILETIME utime;
   double tm;
-  ULARGE_INTEGER utime;
-  GetSystemTimeAsFileTime(&ft);
-  utime.LowPart = ft.dwLowDateTime;
-  utime.HighPart = ft.dwHighDateTime;
-  tm = utime.QuadPart - CAML_NT_EPOCH_100ns_TICKS;
+  GetSystemTimeAsFileTime(&utime.ft);
+  tm = utime.ul - CAML_NT_EPOCH_100ns_TICKS;
   return (tm * 1e-7);  /* tm is in 100ns */
 }
 
diff --git a/otherlibs/unix/times_win32.c b/otherlibs/unix/times_win32.c
index 37fdef9d09..9666a95b1d 100644
--- a/otherlibs/unix/times_win32.c
+++ b/otherlibs/unix/times_win32.c
@@ -18,29 +18,23 @@
 #include "unixsupport.h"
 #include <windows.h>
 
-
-static double to_sec(FILETIME ft) {
-  ULARGE_INTEGER tmp = {{ft.dwLowDateTime, ft.dwHighDateTime}};
-
-  /* convert to seconds:
-     GetProcessTimes returns number of 100-nanosecond intervals */
-  return tmp.QuadPart / 1e7;
-}
-
+#define CAML_INTERNALS
+#include <caml/winsupport.h>
 
 value caml_unix_times(value unit) {
   value res;
-  FILETIME creation, exit, stime, utime;
+  FILETIME _creation, _exit;
+  CAML_ULONGLONG_FILETIME stime, utime;
 
-  if (!(GetProcessTimes(GetCurrentProcess(), &creation, &exit, &stime,
-                        &utime))) {
+  if (!(GetProcessTimes(GetCurrentProcess(), &_creation, &_exit,
+                        &stime.ft, &utime.ft))) {
     caml_win32_maperr(GetLastError());
     caml_uerror("times", Nothing);
   }
 
   res = caml_alloc_small(4 * Double_wosize, Double_array_tag);
-  Store_double_field(res, 0, to_sec(utime));
-  Store_double_field(res, 1, to_sec(stime));
+  Store_double_field(res, 0, (double)(utime.ul / 1e7));
+  Store_double_field(res, 1, (double)(stime.ul / 1e7));
   Store_double_field(res, 2, 0);
   Store_double_field(res, 3, 0);
   return res;
diff --git a/otherlibs/unix/utimes_win32.c b/otherlibs/unix/utimes_win32.c
index f1543eea79..940f25c62a 100644
--- a/otherlibs/unix/utimes_win32.c
+++ b/otherlibs/unix/utimes_win32.c
@@ -20,25 +20,17 @@
 #include <caml/memory.h>
 #include <caml/signals.h>
 #include <caml/osdeps.h>
+#include <caml/winsupport.h>
 #include "unixsupport.h"
 
 #include <windows.h>
 
-static void convert_time(double unixTime, FILETIME* ft)
-{
-  ULARGE_INTEGER u;
-  u.QuadPart =
-    (ULONGLONG)(unixTime * 10000000.0) + CAML_NT_EPOCH_100ns_TICKS;
-  ft->dwLowDateTime = u.LowPart;
-  ft->dwHighDateTime = u.HighPart;
-}
-
 CAMLprim value caml_unix_utimes(value path, value atime, value mtime)
 {
   CAMLparam3(path, atime, mtime);
   WCHAR *wpath;
   HANDLE hFile;
-  FILETIME lastAccessTime, lastModificationTime;
+  CAML_ULONGLONG_FILETIME lastAccessTime, lastModificationTime;
   SYSTEMTIME systemTime;
   double at, mt;
   BOOL res;
@@ -63,14 +55,16 @@ CAMLprim value caml_unix_utimes(value path, value atime, value mtime)
   }
   if (at == 0.0 && mt == 0.0) {
     GetSystemTime(&systemTime);
-    SystemTimeToFileTime(&systemTime, &lastAccessTime);
-    memcpy(&lastModificationTime, &lastAccessTime, sizeof(FILETIME));
+    SystemTimeToFileTime(&systemTime, &lastAccessTime.ft);
+    lastModificationTime.ul = lastAccessTime.ul;
   } else {
-    convert_time(at, &lastAccessTime);
-    convert_time(mt, &lastModificationTime);
+    lastAccessTime.ul =
+      (ULONGLONG)(at * 10000000.0) + CAML_NT_EPOCH_100ns_TICKS;
+    lastModificationTime.ul =
+      (ULONGLONG)(mt * 10000000.0) + CAML_NT_EPOCH_100ns_TICKS;
   }
   caml_enter_blocking_section();
-  res = SetFileTime(hFile, NULL, &lastAccessTime, &lastModificationTime);
+  res = SetFileTime(hFile, NULL, &lastAccessTime.ft, &lastModificationTime.ft);
   caml_leave_blocking_section();
   if (res == 0) {
     caml_win32_maperr(GetLastError());