1 files changed, 104 insertions, 0 deletions
diff --git a/intl/components/src/DateTimeFormatUtils.cpp b/intl/components/src/DateTimeFormatUtils.cpp
new file mode 100644
index 0000000000..fd0649461e
--- /dev/null
+++ b/intl/components/src/DateTimeFormatUtils.cpp
@@ -0,0 +1,104 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Assertions.h"
+
+#include "DateTimeFormatUtils.h"
+
+namespace mozilla::intl {
+
+DateTimePartType ConvertUFormatFieldToPartType(UDateFormatField fieldName) {
+  // See intl/icu/source/i18n/unicode/udat.h for a detailed field list.  This
+  // switch is deliberately exhaustive: cases might have to be added/removed
+  // if this code is compiled with a different ICU with more
+  // UDateFormatField enum initializers.  Please guard such cases with
+  // appropriate ICU version-testing #ifdefs, should cross-version divergence
+  // occur.
+  switch (fieldName) {
+    case UDAT_ERA_FIELD:
+      return DateTimePartType::Era;
+
+    case UDAT_YEAR_FIELD:
+    case UDAT_YEAR_WOY_FIELD:
+    case UDAT_EXTENDED_YEAR_FIELD:
+      return DateTimePartType::Year;
+
+    case UDAT_YEAR_NAME_FIELD:
+      return DateTimePartType::YearName;
+
+    case UDAT_MONTH_FIELD:
+    case UDAT_STANDALONE_MONTH_FIELD:
+      return DateTimePartType::Month;
+
+    case UDAT_DATE_FIELD:
+    case UDAT_JULIAN_DAY_FIELD:
+      return DateTimePartType::Day;
+
+    case UDAT_HOUR_OF_DAY1_FIELD:
+    case UDAT_HOUR_OF_DAY0_FIELD:
+    case UDAT_HOUR1_FIELD:
+    case UDAT_HOUR0_FIELD:
+      return DateTimePartType::Hour;
+
+    case UDAT_MINUTE_FIELD:
+      return DateTimePartType::Minute;
+
+    case UDAT_SECOND_FIELD:
+      return DateTimePartType::Second;
+
+    case UDAT_DAY_OF_WEEK_FIELD:
+    case UDAT_STANDALONE_DAY_FIELD:
+    case UDAT_DOW_LOCAL_FIELD:
+    case UDAT_DAY_OF_WEEK_IN_MONTH_FIELD:
+      return DateTimePartType::Weekday;
+
+    case UDAT_AM_PM_FIELD:
+    case UDAT_FLEXIBLE_DAY_PERIOD_FIELD:
+      return DateTimePartType::DayPeriod;
+
+    case UDAT_TIMEZONE_FIELD:
+    case UDAT_TIMEZONE_GENERIC_FIELD:
+    case UDAT_TIMEZONE_LOCALIZED_GMT_OFFSET_FIELD:
+      return DateTimePartType::TimeZoneName;
+
+    case UDAT_FRACTIONAL_SECOND_FIELD:
+      return DateTimePartType::FractionalSecondDigits;
+
+#ifndef U_HIDE_INTERNAL_API
+    case UDAT_RELATED_YEAR_FIELD:
+      return DateTimePartType::RelatedYear;
+#endif
+
+    case UDAT_DAY_OF_YEAR_FIELD:
+    case UDAT_WEEK_OF_YEAR_FIELD:
+    case UDAT_WEEK_OF_MONTH_FIELD:
+    case UDAT_MILLISECONDS_IN_DAY_FIELD:
+    case UDAT_TIMEZONE_RFC_FIELD:
+    case UDAT_QUARTER_FIELD:
+    case UDAT_STANDALONE_QUARTER_FIELD:
+    case UDAT_TIMEZONE_SPECIAL_FIELD:
+    case UDAT_TIMEZONE_ISO_FIELD:
+    case UDAT_TIMEZONE_ISO_LOCAL_FIELD:
+    case UDAT_AM_PM_MIDNIGHT_NOON_FIELD:
+#ifndef U_HIDE_INTERNAL_API
+    case UDAT_TIME_SEPARATOR_FIELD:
+#endif
+      // These fields are all unsupported.
+      return DateTimePartType::Unknown;
+
+#ifndef U_HIDE_DEPRECATED_API
+    case UDAT_FIELD_COUNT:
+      MOZ_ASSERT_UNREACHABLE(
+          "format field sentinel value returned by "
+          "iterator!");
+#endif
+  }
+
+  MOZ_ASSERT_UNREACHABLE(
+      "unenumerated, undocumented format field returned "
+      "by iterator");
+  return DateTimePartType::Unknown;
+}
+
+}  // namespace mozilla::intl