1 files changed, 59 insertions, 0 deletions
diff --git a/src/corefx/System.Globalization.Native/timeZoneInfo.cpp b/src/corefx/System.Globalization.Native/timeZoneInfo.cpp
new file mode 100644
index 0000000000..d0e01e5ce6
--- /dev/null
+++ b/src/corefx/System.Globalization.Native/timeZoneInfo.cpp
@@ -0,0 +1,59 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+//
+
+#include <stdint.h>
+#include <unistd.h>
+#include <unicode/ucal.h>
+
+#include "locale.hpp"
+#include "holders.h"
+#include "errors.h"
+
+/*
+Gets the symlink value for the path.
+*/
+extern "C" int32_t GlobalizationNative_ReadLink(const char* path, char* result, size_t resultCapacity)
+{
+    ssize_t r = readlink(path, result, resultCapacity - 1); // subtract one to make room for the NULL character
+
+    if (r < 1 || r >= resultCapacity)
+        return false;
+
+    result[r] = '\0';
+    return true;
+}
+
+/*
+These values should be kept in sync with the managed Interop.GlobalizationInterop.TimeZoneDisplayNameType enum.
+*/
+enum TimeZoneDisplayNameType : int32_t
+{
+    Generic = 0,
+    Standard = 1,
+    DaylightSavings = 2,
+};
+
+/*
+Gets the localized display name for the specified time zone.
+*/
+extern "C" ResultCode GlobalizationNative_GetTimeZoneDisplayName(
+    const UChar* localeName, const UChar* timeZoneId, TimeZoneDisplayNameType type, UChar* result, int32_t resultLength)
+{
+    UErrorCode err = U_ZERO_ERROR;
+    char locale[ULOC_FULLNAME_CAPACITY];
+    GetLocale(localeName, locale, ULOC_FULLNAME_CAPACITY, false, &err);
+
+    int32_t timeZoneIdLength = -1; // timeZoneId is NULL-terminated
+    UCalendar* calendar = ucal_open(timeZoneId, timeZoneIdLength, locale, UCAL_DEFAULT, &err);
+    UCalendarHolder calendarHolder(calendar, err);
+
+    // TODO (https://github.com/dotnet/corefx/issues/5741): need to support Generic names, but ICU "C" api
+    // has no public option for this. For now, just use the ICU standard name for both Standard and Generic
+    // (which is the same behavior on Windows with the mincore TIME_ZONE_INFORMATION APIs).
+    ucal_getTimeZoneDisplayName(
+        calendar, type == DaylightSavings ? UCAL_DST : UCAL_STANDARD, locale, result, resultLength, &err);
+
+    return GetResultCode(err);
+}