Index: icu4c/source/test/intltest/tzregts.cpp

===================================================================

--- icu4c/source/test/intltest/tzregts.cpp	(リビジョン 40953)

+++ icu4c/source/test/intltest/tzregts.cpp	(リビジョン 40954)

@@ -12,6 +12,7 @@

 #include "unicode/simpletz.h"

 #include "unicode/smpdtfmt.h"

 #include "unicode/strenum.h"

+#include "unicode/gregocal.h"

 #include "tzregts.h"

 #include "calregts.h"

 #include "cmemory.h"

@@ -46,6 +47,7 @@

         CASE(16, TestJDK12API);

         CASE(17, Test4176686);

         CASE(18, Test4184229);

+        CASE(19, TestNegativeDaylightSaving);

         default: name = ""; break;

     }

 }

@@ -709,10 +711,10 @@

     int32_t DATA [] = {

         1, GOOD,

         0, BAD,

-        -1, BAD,

+        -1, GOOD,   // #13566 updates SimpleTimeZone to support negative DST saving amount

         60*60*1000, GOOD,

-        INT32_MIN, BAD,

-        // Integer.MAX_VALUE, ?, // no upper limit on DST savings at this time

+        INT32_MAX, GOOD,    // no upper limit on DST savings at this time

+        INT32_MIN, GOOD     // no lower limit as well

     };

     UErrorCode status = U_ZERO_ERROR;

@@ -1206,4 +1208,61 @@

     delete zone;

 }

+void TimeZoneRegressionTest::TestNegativeDaylightSaving() {

+    UErrorCode status = U_ZERO_ERROR;

+    int32_t stdOff = 1 * 60*60*1000;    // Standard offset UTC+1

+    int save = -1 * 60*60*1000;     // DST saving amount -1 hour

+    SimpleTimeZone stzDublin(stdOff, "Dublin-2018",

+                                UCAL_OCTOBER, -1, -UCAL_SUNDAY, 2*60*60*1000,

+                                UCAL_MARCH, -1, -UCAL_SUNDAY, 1*60*60*1000,

+                                save, status);

+    failure(status, "SimpleTimeZone constructor");

+

+    if (save != stzDublin.getDSTSavings()) {

+        errln((UnicodeString)"FAIL: DST saving is not " + save);

+    }

+

+    GregorianCalendar cal(* TimeZone::getGMT(), status);

+    failure(status, "GregorianCalendar constructor");

+

+    UDate testDate;

+    int32_t rawOffset;

+    int32_t dstOffset;

+

+    cal.set(2018, UCAL_JANUARY, 15, 0, 0, 0);

+    testDate = cal.getTime(status);

+    failure(status, "calendar getTime() - Jan 15");

+

+    if (!stzDublin.inDaylightTime(testDate, status)) {

+        errln("FAIL: The test date (Jan 15) must be in DST.");

+    }

+    failure(status, "inDaylightTime() - Jan 15");

+

+    stzDublin.getOffset(testDate, FALSE, rawOffset, dstOffset, status);

+    failure(status, "getOffset() - Jan 15");

+    if (rawOffset != stdOff || dstOffset != save) {

+        errln((UnicodeString)"FAIL: Expected [stdoff=" + stdOff + ",save=" + save

+            + "] on the test date (Jan 15), actual[stdoff=" + rawOffset

+            + ",save=" + dstOffset + "]");

+    }

+

+    cal.set(2018, UCAL_JULY, 15, 0, 0, 0);

+    testDate = cal.getTime(status);

+    failure(status, "calendar getTime() - Jul 15");

+

+    if (stzDublin.inDaylightTime(testDate, status)) {

+        errln("FAIL: The test date (Jul 15) must be in DST.");

+    }

+    failure(status, "inDaylightTime() - Jul 15");

+

+    stzDublin.getOffset(testDate, FALSE, rawOffset, dstOffset, status);

+    failure(status, "getOffset() - Jul 15");

+    if (rawOffset != stdOff || dstOffset != 0) {

+        errln((UnicodeString)"FAIL: Expected [stdoff=" + stdOff + ",save=" + 0

+            + "] on the test date (Jul 15), actual[stdoff=" + rawOffset

+            + ",save=" + dstOffset + "]");

+    }

+}

+

+

 #endif /* #if !UCONFIG_NO_FORMATTING */

Index: icu4c/source/test/intltest/tzregts.h

===================================================================

--- icu4c/source/test/intltest/tzregts.h	(リビジョン 40953)

+++ icu4c/source/test/intltest/tzregts.h	(リビジョン 40954)

@@ -49,6 +49,7 @@

     void TestJDK12API(void);

     void Test4184229(void);

     UBool checkCalendar314(GregorianCalendar *testCal, TimeZone *testTZ);

+    void TestNegativeDaylightSaving(void);

 protected:

Index: icu4c/source/i18n/simpletz.cpp

===================================================================

--- icu4c/source/i18n/simpletz.cpp	(リビジョン 40953)

+++ icu4c/source/i18n/simpletz.cpp	(リビジョン 40954)

@@ -177,7 +177,7 @@

     decodeRules(status);

-    if (savingsDST <= 0) {

+    if (savingsDST == 0) {

         status = U_ILLEGAL_ARGUMENT_ERROR;

     }

 }

@@ -686,7 +686,7 @@

 void 

 SimpleTimeZone::setDSTSavings(int32_t millisSavedDuringDST, UErrorCode& status) 

 {

-    if (millisSavedDuringDST <= 0) {

+    if (millisSavedDuringDST == 0) {

         status = U_ILLEGAL_ARGUMENT_ERROR;

     }

     else {

Index: icu4c/source/i18n/unicode/simpletz.h

===================================================================

--- icu4c/source/i18n/unicode/simpletz.h	(リビジョン 40953)

+++ icu4c/source/i18n/unicode/simpletz.h	(リビジョン 40954)

@@ -647,7 +647,8 @@

      * Sets the amount of time in ms that the clock is advanced during DST.

      * @param millisSavedDuringDST the number of milliseconds the time is

      * advanced with respect to standard time when the daylight savings rules

-     * are in effect. A positive number, typically one hour (3600000).

+     * are in effect. Typically one hour (+3600000). The amount could be negative,

+     * but not 0.

      * @param status  An UErrorCode to receive the status.

      * @stable ICU 2.0

      */

@@ -657,7 +658,8 @@

      * Returns the amount of time in ms that the clock is advanced during DST.

      * @return the number of milliseconds the time is

      * advanced with respect to standard time when the daylight savings rules

-     * are in effect. A positive number, typically one hour (3600000).

+     * are in effect. Typically one hour (+3600000). The amount could be negative,

+     * but not 0.

      * @stable ICU 2.0

      */

     virtual int32_t getDSTSavings(void) const;