ucrtbase: Implement %G format for strftime.

dlls/msvcrt/time.c

@@ -1196,6 +1196,15 @@ static MSVCRT_size_t strftime_helper(char *str, MSVCRT_size_t max, const char *f
             if(!strftime_int(str, &ret, max, mstm->tm_mday, alternate ? 0 : 2, 0, 31))
                 return 0;
             break;
+        case 'G':
+            tmp = 1900 + mstm->tm_year;
+            if (mstm->tm_yday - (mstm->tm_wday ? mstm->tm_wday : 7) + 4 < 0)
+                tmp--;
+            else if(mstm->tm_yday - (mstm->tm_wday ? mstm->tm_wday : 7) + 5 > 365 + IsLeapYear(tmp))
+                tmp++;
+            if (!strftime_int(str, &ret, max, tmp, 4, 0, 9999))
+                return 0;
+            break;
 #endif
         case 'H':
             if(!strftime_int(str, &ret, max, mstm->tm_hour, alternate ? 0 : 2, 0, 23))

dlls/ucrtbase/tests/misc.c

@@ -138,6 +138,7 @@ static void (CDECL *p___setusermatherr)(MSVCRT_matherr_func);
 static int* (CDECL *p_errno)(void);
 static char* (CDECL *p_asctime)(const struct tm *);
 static size_t (__cdecl *p_strftime)(char *, size_t, const char *, const struct tm *);
+static struct tm*  (__cdecl *p__gmtime32)(const __time32_t*);
 static void (CDECL *p_exit)(int);
 static int (CDECL *p__crt_atexit)(void (CDECL*)(void));
 static int (__cdecl *p_crt_at_quick_exit)(void (__cdecl *func)(void));
@@ -509,6 +510,7 @@ static BOOL init(void)
     p_errno = (void*)GetProcAddress(module, "_errno");
     p_asctime = (void*)GetProcAddress(module, "asctime");
     p_strftime = (void*)GetProcAddress(module, "strftime");
+    p__gmtime32 = (void*)GetProcAddress(module, "_gmtime32");
     p__crt_atexit = (void*)GetProcAddress(module, "_crt_atexit");
     p_exit = (void*)GetProcAddress(module, "exit");
     p_crt_at_quick_exit = (void*)GetProcAddress(module, "_crt_at_quick_exit");
@@ -904,6 +906,7 @@ static void test_strftime(void)
     const struct tm tm1 = { 0, 0, 0, 1, 0, 117, 0, 0, 0 };
     char bufA[256];
     size_t retA;
+    int i;
 
     retA = p_strftime(bufA, sizeof(bufA), "%C", &epoch);
     ok(retA == 2, "expected 2, got %d\n", (int)retA);
@@ -964,6 +967,27 @@ static void test_strftime(void)
     retA = p_strftime(bufA, sizeof(bufA), "%t", &epoch);
     ok(retA == 1, "expected 1, got %d\n", (int)retA);
     ok(!strcmp(bufA, "\t"), "got %s\n", bufA);
+
+    retA = p_strftime(bufA, sizeof(bufA), "%G", &epoch);
+    ok(retA == 4, "expected 4, got %d\n", (int)retA);
+    ok(!strcmp(bufA, "1970"), "got %s\n", bufA);
+
+    retA = p_strftime(bufA, sizeof(bufA), "%G", &tm1);
+    ok(retA == 4, "expected 4, got %d\n", (int)retA);
+    ok(!strcmp(bufA, "2016"), "got %s\n", bufA);
+
+    for(i=0; i<14; i++)
+    {
+        __time32_t t = (365*2 + i - 7) * 24 * 60 * 60;
+        struct tm tm = *p__gmtime32(&t);
+
+        retA = p_strftime(bufA, sizeof(bufA), "%G", &tm);
+        ok(retA == 4, "%d) retA = %d\n", i, (int)retA);
+        if (i <= 8)
+            ok(!strcmp(bufA, "1971"), "%d) got %s, expected 1971\n", i, bufA);
+        else
+            ok(!strcmp(bufA, "1972"), "%d) got %s, expected 1972\n", i, bufA);
+    }
 }
 
 static LONG* get_failures_counter(HANDLE *map)