ntdll: Return correct time zone names for Asia/Tokyo and Asia/Yakutsk.

Without this change, for Japan, Wine returns "Korea Standard Time",
not "Tokyo Standard Time" as seen in Bug 42719.

Actually, this is a regression by d666143f88.
The new code relies on offsets from UTC and DST change timings.  However,
Northeast Asia regions don't use daylight saving time.  Thus, Wine can't
distinguish between these regions.

Signed-off-by: Akihiro Sagawa <sagawa.aki@gmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/ntdll/time.c

@@ -53,6 +53,12 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(ntdll);
 
+#define SHORT_TZ_NAME_MAX 8
+struct tz_name_map {
+    WCHAR key_name[128];
+    char short_name[SHORT_TZ_NAME_MAX];
+};
+
 static int init_tz_info(RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi);
 
 static RTL_CRITICAL_SECTION TIME_tz_section;
@@ -571,6 +577,42 @@ static BOOL match_tz_info(const RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi, const RT
     return FALSE;
 }
 
+static int compare_tz_key(const void *a, const void *b)
+{
+    const struct tz_name_map *map_a, *map_b;
+    map_a = (const struct tz_name_map *)a;
+    map_b = (const struct tz_name_map *)b;
+    return strcmpW(map_a->key_name, map_b->key_name);
+}
+
+static BOOL match_tz_name(const char* tz_name,
+                          const RTL_DYNAMIC_TIME_ZONE_INFORMATION *reg_tzi)
+{
+    static const struct tz_name_map mapping[] = {
+        { {'K','o','r','e','a',' ','S','t','a','n','d','a','r','d',' ','T','i',
+           'm','e',0 },
+          "KST" },
+        { {'T','o','k','y','o',' ','S','t','a','n','d','a','r','d',' ','T','i',
+           'm','e',0 },
+          "JST" },
+        { {'Y','a','k','u','t','s','k',' ','S','t','a','n','d','a','r','d',' ',
+           'T','i','m','e',0 },
+          "+09" }, /* YAKST was used until tzdata 2016f */
+    };
+    struct tz_name_map *match, key;
+
+    if (reg_tzi->DaylightDate.wMonth)
+        return TRUE;
+
+    strcpyW(key.key_name, reg_tzi->TimeZoneKeyName);
+    match = bsearch(&key, mapping, sizeof(mapping)/sizeof(mapping[0]),
+                    sizeof(mapping[0]), compare_tz_key);
+    if (!match)
+        return TRUE;
+
+    return !strcmp(match->short_name, tz_name);
+}
+
 static BOOL reg_query_value(HKEY hkey, LPCWSTR name, DWORD type, void *data, DWORD count)
 {
     UNICODE_STRING nameW;
@@ -592,7 +634,7 @@ static BOOL reg_query_value(HKEY hkey, LPCWSTR name, DWORD type, void *data, DWO
     return TRUE;
 }
 
-static void find_reg_tz_info(RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi, int year)
+static void find_reg_tz_info(RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi, const char* tz_name, int year)
 {
     static const WCHAR Time_ZonesW[] = { 'M','a','c','h','i','n','e','\\',
         'S','o','f','t','w','a','r','e','\\',
@@ -714,7 +756,8 @@ static void find_reg_tz_info(RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi, int year)
 
         NtClose(hSubkey);
 
-        if (match_tz_info(tzi, &reg_tzi))
+        if (match_tz_info(tzi, &reg_tzi)
+            && match_tz_name(tz_name, &reg_tzi))
         {
             *tzi = reg_tzi;
             NtClose(hkey);
@@ -729,8 +772,8 @@ static void find_reg_tz_info(RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi, int year)
     NtClose(hkey);
 
     FIXME("Can't find matching timezone information in the registry for "
-          "bias %d, std (d/m/y): %u/%02u/%04u, dlt (d/m/y): %u/%02u/%04u\n",
+          "%s, bias %d, std (d/m/y): %u/%02u/%04u, dlt (d/m/y): %u/%02u/%04u\n",
-          tzi->Bias,
+          tz_name, tzi->Bias,
           tzi->StandardDate.wDay, tzi->StandardDate.wMonth, tzi->StandardDate.wYear,
           tzi->DaylightDate.wDay, tzi->DaylightDate.wMonth, tzi->DaylightDate.wYear);
 }
@@ -763,6 +806,7 @@ static int init_tz_info(RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi)
     static RTL_DYNAMIC_TIME_ZONE_INFORMATION cached_tzi;
     static int current_year = -1, current_bias = 65535;
     struct tm *tm;
+    char tz_name[SHORT_TZ_NAME_MAX];
     time_t year_start, year_end, tmp, dlt = 0, std = 0;
     int is_dst, current_is_dst, bias;
 
@@ -782,6 +826,10 @@ static int init_tz_info(RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi)
     }
 
     memset(tzi, 0, sizeof(*tzi));
+    if (!strftime(tz_name, sizeof(tz_name), "%Z", tm)) {
+        /* not enough room or another error */
+        tz_name[0] = '\0';
+    }
 
     TRACE("tz data will be valid through year %d, bias %d\n", tm->tm_year + 1900, bias);
     current_year = tm->tm_year;
@@ -864,7 +912,7 @@ static int init_tz_info(RTL_DYNAMIC_TIME_ZONE_INFORMATION *tzi)
             tzi->StandardBias);
     }
 
-    find_reg_tz_info(tzi, current_year + 1900);
+    find_reg_tz_info(tzi, tz_name, current_year + 1900);
     cached_tzi = *tzi;
 
     RtlLeaveCriticalSection( &TIME_tz_section );