Daniel Lehman : msvcrt: Return wall-clock time from clock().

[Alexandre Julliard]

Module: wine
Branch: stable
Commit: ed8357ee890e359fb3660cd1b39a31ec353a1af0
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=ed8357ee890e359fb3660cd1b39a31ec353a1af0

Author: Daniel Lehman <dlehman at esri.com>
Date:   Wed Jul 27 16:42:53 2011 -0700

msvcrt: Return wall-clock time from clock().

(cherry picked from commit 15b35f4d37e4bdd8d2b44b772e800a8ffade7ab6)

---

 dlls/msvcrt/time.c |   25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/dlls/msvcrt/time.c b/dlls/msvcrt/time.c
index 4c21380..11a5df9 100644
--- a/dlls/msvcrt/time.c
+++ b/dlls/msvcrt/time.c
@@ -30,6 +30,7 @@
 #include "mtdll.h"
 #include "winbase.h"
 #include "winnls.h"
+#include "winternl.h"
 #include "wine/debug.h"
 #include "wine/unicode.h"
 
@@ -709,19 +710,23 @@ int CDECL _wstrtime_s(MSVCRT_wchar_t* time, MSVCRT_size_t size)
  */
 MSVCRT_clock_t CDECL MSVCRT_clock(void)
 {
-  FILETIME ftc, fte, ftk, ftu;
-  ULONGLONG utime, ktime;
- 
-  MSVCRT_clock_t clock;
+    static LONGLONG start_time;
+    LARGE_INTEGER systime;
 
-  GetProcessTimes(GetCurrentProcess(), &ftc, &fte, &ftk, &ftu);
+    if(!start_time) {
+        KERNEL_USER_TIMES pti;
 
-  ktime = ((ULONGLONG)ftk.dwHighDateTime << 32) | ftk.dwLowDateTime;
-  utime = ((ULONGLONG)ftu.dwHighDateTime << 32) | ftu.dwLowDateTime;
-
-  clock = (utime + ktime) / (TICKSPERSEC / MSVCRT_CLOCKS_PER_SEC);
+        /* while Linux's clock returns user time, Windows' clock
+         * returns wall-clock time from process start.  cache the
+         * process start time since it won't change and to avoid
+         * wineserver round-trip overhead */
+        if(NtQueryInformationProcess(GetCurrentProcess(), ProcessTimes, &pti, sizeof(pti), NULL))
+            return -1;
+        start_time = pti.CreateTime.QuadPart;
+    }
 
-  return clock;
+    NtQuerySystemTime(&systime);
+    return (systime.QuadPart - start_time) * MSVCRT_CLOCKS_PER_SEC / TICKSPERSEC;
 }
 
 /*********************************************************************