--- /dev/null
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_FIXED_H_
+#define ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_FIXED_H_
+
+#include <string>
+
+#include "absl/time/internal/cctz/include/cctz/time_zone.h"
+
+namespace absl {
+namespace time_internal {
+namespace cctz {
+
+// Helper functions for dealing with the names and abbreviations
+// of time zones that are a fixed offset (seconds east) from UTC.
+// FixedOffsetFromName() extracts the offset from a valid fixed-offset
+// name, while FixedOffsetToName() and FixedOffsetToAbbr() generate
+// the canonical zone name and abbreviation respectively for the given
+// offset.
+//
+// A fixed-offset name looks like "Fixed/UTC<+-><hours>:<mins>:<secs>".
+// Its abbreviation is of the form "UTC(<+->H?H(MM(SS)?)?)?" where the
+// optional pieces are omitted when their values are zero. (Note that
+// the sign is the opposite of that used in a POSIX TZ specification.)
+//
+// Note: FixedOffsetFromName() fails on syntax errors or when the parsed
+// offset exceeds 24 hours. FixedOffsetToName() and FixedOffsetToAbbr()
+// both produce "UTC" when the argument offset exceeds 24 hours.
+bool FixedOffsetFromName(const std::string& name, seconds* offset);
+std::string FixedOffsetToName(const seconds& offset);
+std::string FixedOffsetToAbbr(const seconds& offset);
+
+} // namespace cctz
+} // namespace time_internal
+} // namespace absl
+
+#endif // ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_FIXED_H_