libroot: implement timegm calling the ICU backend

Change-Id: Ib4de4288e061670acbc2edea3671cee029305d33
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3748
Reviewed-by: Axel Dörfler <[email protected]>

headers/private/libroot/locale/ICULocaleBackend.h

@@ -73,6 +73,8 @@ public:
 
 	virtual status_t			Mktime(struct tm* inOutTm, time_t& timeOut);
 
+	virtual status_t			Timegm(struct tm* inOutTm, time_t& timeOut);
+
 private:
 			const char*			_QueryLocale(int category);
 			const char*			_SetPosixLocale(int category);

headers/private/libroot/locale/ICUTimeConversion.h

@@ -34,11 +34,17 @@ public:
 
 			status_t			Mktime(struct tm* inOutTm, time_t& timeOut);
 
+			status_t			Timegm(struct tm* inOutTm, time_t& timeOut);
+
 private:
 			status_t			_FillTmValues(const U_NAMESPACE_QUALIFIER
 										TimeZone* icuTimeZone,
 									const time_t* inTime, struct tm* tmOut);
 
+			status_t			_Mktime(const U_NAMESPACE_QUALIFIER
+										TimeZone* icuTimeZone,
+									struct tm* inOutTm, time_t& timeOut);
+
 			const ICUTimeData&	fTimeData;
 
 			TimeConversionDataBridge*	fDataBridge;

headers/private/libroot/locale/LocaleBackend.h

@@ -157,6 +157,8 @@ public:
 									struct tm* tmOut) = 0;
 	virtual status_t			Mktime(struct tm* inOutTm, time_t& timeOut) = 0;
 
+	virtual status_t			Timegm(struct tm* inOutTm, time_t& timeOut) = 0;
+
 	virtual void				Initialize(LocaleDataBridge* dataBridge) = 0;
 
 	static	status_t			LoadBackend();

src/system/libroot/add-ons/icu/ICULocaleBackend.cpp

@@ -353,6 +353,15 @@ ICULocaleBackend::Mktime(struct tm* inOutTm, time_t& timeOut)
 }
 
 
+status_t
+ICULocaleBackend::Timegm(struct tm* inOutTm, time_t& timeOut)
+{
+	ErrnoMaintainer errnoMaintainer;
+
+	return fTimeConversion.Timegm(inOutTm, timeOut);
+}
+
+
 const char*
 ICULocaleBackend::_QueryLocale(int category)
 {

src/system/libroot/add-ons/icu/ICUTimeConversion.cpp

@@ -166,25 +166,15 @@ ICUTimeConversion::Gmtime(const time_t* inTime, struct tm* tmOut)
 status_t
 ICUTimeConversion::Mktime(struct tm* inOutTm, time_t& timeOut)
 {
-	if (fTimeZone == NULL)
-		return B_NO_INIT;
+	return _Mktime(fTimeZone, inOutTm, timeOut);
+}
 
-	UErrorCode icuStatus = U_ZERO_ERROR;
-	GregorianCalendar calendar(*fTimeZone, fTimeData.ICULocale(),
-		icuStatus);
-	if (!U_SUCCESS(icuStatus))
-		return B_ERROR;
 
-	calendar.setLenient(TRUE);
-	calendar.set(inOutTm->tm_year + 1900, inOutTm->tm_mon, inOutTm->tm_mday,
-		inOutTm->tm_hour, inOutTm->tm_min, inOutTm->tm_sec);
-
-	UDate timeInMillis = calendar.getTime(icuStatus);
-	if (!U_SUCCESS(icuStatus))
-		return B_ERROR;
-	timeOut = (time_t)((int64_t)timeInMillis / 1000);
-
-	return _FillTmValues(fTimeZone, &timeOut, inOutTm);
+status_t
+ICUTimeConversion::Timegm(struct tm* inOutTm, time_t& timeOut)
+{
+	const TimeZone* icuTimeZone = TimeZone::getGMT();
+	return _Mktime(icuTimeZone, inOutTm, timeOut);
 }
 
 
@@ -238,5 +228,31 @@ ICUTimeConversion::_FillTmValues(const TimeZone* icuTimeZone,
 }
 
 
+status_t
+ICUTimeConversion::_Mktime(const TimeZone* icuTimeZone,
+	struct tm* inOutTm, time_t& timeOut)
+{
+	if (icuTimeZone == NULL)
+		return B_NO_INIT;
+
+	UErrorCode icuStatus = U_ZERO_ERROR;
+	GregorianCalendar calendar(*icuTimeZone, fTimeData.ICULocale(),
+		icuStatus);
+	if (!U_SUCCESS(icuStatus))
+		return B_ERROR;
+
+	calendar.setLenient(TRUE);
+	calendar.set(inOutTm->tm_year + 1900, inOutTm->tm_mon, inOutTm->tm_mday,
+		inOutTm->tm_hour, inOutTm->tm_min, inOutTm->tm_sec);
+
+	UDate timeInMillis = calendar.getTime(icuStatus);
+	if (!U_SUCCESS(icuStatus))
+		return B_ERROR;
+	timeOut = (time_t)((int64_t)timeInMillis / 1000);
+
+	return _FillTmValues(icuTimeZone, &timeOut, inOutTm);
+}
+
+
 }	// namespace Libroot
 }	// namespace BPrivate

src/system/libroot/posix/time/localtime.cpp

@@ -33,10 +33,11 @@ long timezone = 0;
 int daylight = 0;
 
 
-// These two functions are used as a fallback when the locale backend could not
+// These three functions are used as a fallback when the locale backend could not
 // be loaded. They are implemented in localtime_fading_out.c.
 extern "C" struct tm* __gmtime_r_fallback(const time_t* timep, struct tm* tmp);
 extern "C" time_t __mktime_fallback(struct tm* tmp);
+extern "C" time_t __timegm_fallback(struct tm* tmp);
 
 
 extern "C" void
@@ -143,3 +144,29 @@ mktime(struct tm* inTm)
 	// implementation.
 	return __mktime_fallback(inTm);
 }
+
+
+extern "C" time_t
+timegm(struct tm* inTm)
+{
+	if (inTm == NULL) {
+		__set_errno(EINVAL);
+		return -1;
+	}
+	tzset();
+	if (gLocaleBackend != NULL) {
+		time_t timeOut;
+		status_t status = gLocaleBackend->Timegm(inTm, timeOut);
+
+		if (status != B_OK) {
+			__set_errno(EOVERFLOW);
+			return -1;
+		}
+
+		return timeOut;
+	}
+
+	// without a locale backend, we fall back to using a basic timegm
+	// implementation.
+	return __timegm_fallback(inTm);
+}

src/system/libroot/posix/time/localtime_fading_out.c

@@ -169,7 +169,7 @@ static int		tmcomp P((const struct tm * atmp,
 */
 struct tm* __gmtime_r_fallback(const time_t* timep, struct tm* tmp);
 time_t __mktime_fallback(struct tm* tmp);
-time_t timegm(struct tm* const tmp);
+time_t __timegm_fallback(struct tm* const tmp);
 
 static struct state	lclmem;
 static struct state	gmtmem;
@@ -831,10 +831,8 @@ __mktime_fallback(struct tm* tmp)
 }
 
 
-
 time_t
-timegm(tmp)
-struct tm * const	tmp;
+__timegm_fallback(struct tm* const tmp)
 {
 	tmp->tm_isdst = 0;
 	return time1(tmp, gmtsub, 0L);