Implement support for "%z" in wxDateTime::Format() and Parse().

"%z" specifier can now be used when printing the dates out to specify the time
zone and is also recognized when parsing dates.

Closes #1215.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70268 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -451,6 +451,7 @@ Major new features in this release
 All:
 
 - Added wxLogFormatter to allow customizing wxLog output (Sébastien Gallou).
+- Added "%z" support to wxDateTime::Format() and Parse() (Armel Asselin).
 
 All (GUI):
 

src/common/datetimefmt.cpp

@@ -319,11 +319,17 @@ wxString wxDateTime::Format(const wxString& formatp, const TimeZone& tz) const
     format.Replace("%X",wxLocale::GetInfo(wxLOCALE_TIME_FMT));
 #endif
     // we have to use our own implementation if the date is out of range of
-    // strftime() or if we use non standard specifiers
+    // strftime() or if we use non standard specifiers (notice that "%z" is
+    // special because it is de facto standard under Unix but is not supported
+    // under Windows)
 #ifdef wxHAS_STRFTIME
     time_t time = GetTicks();
 
-    if ( (time != (time_t)-1) && !wxStrstr(format, wxT("%l")) )
+    if ( (time != (time_t)-1) && !wxStrstr(format, wxT("%l"))
+#ifdef __WXMSW__
+            && !wxStrstr(format, wxT("%z"))
+#endif
+       )
     {
         // use strftime()
         struct tm tmstruct;
@@ -397,6 +403,7 @@ wxString wxDateTime::Format(const wxString& formatp, const TimeZone& tz) const
         switch ( (*++p).GetValue() )
         {
             case wxT('Y'):               // year has 4 digits
+            case wxT('z'):               // time zone as well
                 fmt = wxT("%04d");
                 break;
 
@@ -639,6 +646,25 @@ wxString wxDateTime::Format(const wxString& formatp, const TimeZone& tz) const
                     res += wxString::Format(fmt, tm.year);
                     break;
 
+                case wxT('z'):       // time zone as [-+]HHMM
+                    {
+                        int ofs = tz.GetOffset();
+                        if ( ofs < 0 )
+                        {
+                            res += '-';
+                            ofs = -ofs;
+                        }
+                        else
+                        {
+                            res += '+';
+                        }
+
+                        // Converts seconds to HHMM representation.
+                        res += wxString::Format(fmt,
+                                                100*(ofs/3600) + (ofs/60)%60);
+                    }
+                    break;
+
                 case wxT('Z'):       // timezone name
 #ifdef wxHAS_STRFTIME
                     res += CallStrftime(wxT("%Z"), &tmTimeOnly);
@@ -929,6 +955,8 @@ wxDateTime::ParseFormat(const wxString& date,
     bool hourIsIn12hFormat = false, // or in 24h one?
          isPM = false;              // AM by default
 
+    bool haveTimeZone = false;
+
     // and the value of the items we have (init them to get rid of warnings)
     wxDateTime_t msec = 0,
                  sec = 0,
@@ -939,6 +967,7 @@ wxDateTime::ParseFormat(const wxString& date,
                  mday = 0;
     wxDateTime::Month mon = Inv_Month;
     int year = 0;
+    long timeZone = 0;  // time zone in seconds as expected in Tm structure
 
     wxString::const_iterator input = date.begin();
     const wxString::const_iterator end = date.end();
@@ -1377,6 +1406,36 @@ wxDateTime::ParseFormat(const wxString& date,
                 year = (wxDateTime_t)num;
                 break;
 
+            case wxT('z'):
+                {
+                    bool minusFound;
+                    if ( *input == wxT('-') )
+                        minusFound = true;
+                    else if ( *input == wxT('+') )
+                        minusFound = false;
+                    else
+                        return false;   // no match
+
+                    // here should follow 4 digits HHMM
+                    ++input;
+                    unsigned long tzHourMin;
+                    if ( !GetNumericToken(4, input, end, &tzHourMin) )
+                        return false;   // no match
+
+                    const unsigned hours = tzHourMin / 100;
+                    const unsigned minutes = tzHourMin % 100;
+
+                    if ( hours > 12 || minutes > 59 )
+                        return false;   // bad format
+
+                    timeZone = 3600*hours + 60*minutes;
+                    if ( minusFound )
+                        timeZone = -timeZone;
+
+                    haveTimeZone = true;
+                }
+                break;
+
             case wxT('Z'):       // timezone name
                 // FIXME: currently we just ignore everything that looks like a
                 //        time zone here
@@ -1482,6 +1541,14 @@ wxDateTime::ParseFormat(const wxString& date,
 
     Set(tm);
 
+    // If a time zone was specified and it is not the local time zone, we need
+    // to shift the time accordingly.
+    //
+    // Note that avoiding the call to MakeFromTimeZone is necessary to avoid
+    // DST problems.
+    if ( haveTimeZone && timeZone != -wxGetTimeZone() )
+        MakeFromTimezone(timeZone);
+
     // finally check that the week day is consistent -- if we had it
     if ( haveWDay && GetWeekDay() != wday )
         return false;

tests/datetime/datetimetest.cpp

@@ -666,6 +666,18 @@ void DateTimeTestCase::TestTimeFormat()
        { CompareTime, "Time is %H:%M:%S or %I:%M:%S %p" },
        { CompareNone, "The day of year: %j, the week of year: %W" },
        { CompareDate, "ISO date without separators: %Y%m%d" },
+       { CompareBoth, "RFC 2822 string: %Y-%m-%d %H:%M:%S.%l %z" },
+
+    };
+
+    const long timeZonesOffsets[] =
+    {
+        wxDateTime::TimeZone(wxDateTime::Local).GetOffset(),
+
+        // Fictitious TimeZone offsets to ensure time zone formating and
+        // interpretation works
+        -(3600 + 2*60),
+        3*3600 + 30*60
     };
 
     static const Date formatTestDates[] =
@@ -686,6 +698,11 @@ void DateTimeTestCase::TestTimeFormat()
 #endif
     };
 
+    for ( unsigned idxtz = 0; idxtz < WXSIZEOF(timeZonesOffsets); ++idxtz )
+    {
+        wxDateTime::TimeZone tz(timeZonesOffsets[idxtz]);
+        const bool isLocalTz = tz.GetOffset() == -wxGetTimeZone();
+
         for ( size_t d = 0; d < WXSIZEOF(formatTestDates); d++ )
         {
             wxDateTime dt = formatTestDates[d].DT();
@@ -700,11 +717,31 @@ void DateTimeTestCase::TestTimeFormat()
                 if (am.empty() && pm.empty() && wxStrstr(fmt, "%p") != NULL)
                     continue;
 
-            wxString s = dt.Format(fmt);
-
                 // what can we recover?
                 CompareKind kind = formatTestFormats[n].compareKind;
 
+                // When using a different time zone we must perform a time zone
+                // conversion below which doesn't always work correctly, check
+                // for the cases when it doesn't.
+                if ( !isLocalTz )
+                {
+                    // DST computation doesn't work correctly for dates above
+                    // 2038 currently on the systems with 32 bit time_t.
+                    if ( dt.GetYear() >= 2038 )
+                        continue;
+
+                    // We can't compare just dates nor just times when doing TZ
+                    // conversion as both are affected by the DST: for the
+                    // dates, the DST can switch midnight to 23:00 of the
+                    // previous day while for the times DST can be different
+                    // for the original date and today.
+                    if ( kind == CompareDate || kind == CompareTime )
+                        continue;
+                }
+
+                // do convert date to string
+                wxString s = dt.Format(fmt, tz);
+
                 // convert back
                 wxDateTime dt2;
                 const char *result = dt2.ParseFormat(s, fmt);
@@ -731,6 +768,12 @@ void DateTimeTestCase::TestTimeFormat()
                         !*result
                     );
 
+                    // Without "%z" we can't recover the time zone used in the
+                    // call to Format() so we need to call MakeFromTimezone()
+                    // explicitly.
+                    if ( !strstr(fmt, "%z") && !isLocalTz )
+                        dt2.MakeFromTimezone(tz);
+
                     switch ( kind )
                     {
                         case CompareYear:
@@ -762,6 +805,7 @@ void DateTimeTestCase::TestTimeFormat()
                 }
             }
         }
+    }
 
     wxDateTime dt;
 
@@ -1096,6 +1140,12 @@ void DateTimeTestCase::TestDateTimeParse()
             {  1, wxDateTime::Jan, 9999,  0,  0,  0},
             false
         },
+
+        {
+            "2012-01-01 10:12:05 +0100",
+            {  1, wxDateTime::Jan, 2012,  10,  12,  5, -1 },
+            false // ParseDateTime does know yet +0100
+        },
     };
 
     // the test strings here use "PM" which is not available in all locales so