1 files changed, 70 insertions, 0 deletions
diff --git a/absl/time/internal/cctz/src/time_zone_if.h b/absl/time/internal/cctz/src/time_zone_if.h
new file mode 100644
index 000000000000..ce4da1b728b6
--- /dev/null
+++ b/absl/time/internal/cctz/src/time_zone_if.h
@@ -0,0 +1,70 @@
+// 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
+//
+//   http://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_IF_H_
+#define ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_IF_H_
+
+#include <chrono>
+#include <cstdint>
+#include <memory>
+#include <string>
+
+#include "absl/time/internal/cctz/include/cctz/civil_time.h"
+#include "absl/time/internal/cctz/include/cctz/time_zone.h"
+
+namespace absl {
+namespace time_internal {
+namespace cctz {
+
+// A simple interface used to hide time-zone complexities from time_zone::Impl.
+// Subclasses implement the functions for civil-time conversions in the zone.
+class TimeZoneIf {
+ public:
+  // A factory function for TimeZoneIf implementations.
+  static std::unique_ptr<TimeZoneIf> Load(const std::string& name);
+
+  virtual ~TimeZoneIf();
+
+  virtual time_zone::absolute_lookup BreakTime(
+      const time_point<sys_seconds>& tp) const = 0;
+  virtual time_zone::civil_lookup MakeTime(
+      const civil_second& cs) const = 0;
+
+  virtual std::string Description() const = 0;
+  virtual bool NextTransition(time_point<sys_seconds>* tp) const = 0;
+  virtual bool PrevTransition(time_point<sys_seconds>* tp) const = 0;
+
+ protected:
+  TimeZoneIf() {}
+};
+
+// Convert between time_point<sys_seconds> and a count of seconds since
+// the Unix epoch.  We assume that the std::chrono::system_clock and the
+// Unix clock are second aligned, but not that they share an epoch.
+inline std::int_fast64_t ToUnixSeconds(const time_point<sys_seconds>& tp) {
+  return (tp - std::chrono::time_point_cast<sys_seconds>(
+                   std::chrono::system_clock::from_time_t(0)))
+      .count();
+}
+inline time_point<sys_seconds> FromUnixSeconds(std::int_fast64_t t) {
+  return std::chrono::time_point_cast<sys_seconds>(
+             std::chrono::system_clock::from_time_t(0)) +
+         sys_seconds(t);
+}
+
+}  // namespace cctz
+}  // namespace time_internal
+}  // namespace absl
+
+#endif  // ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_IF_H_