1 files changed, 140 insertions, 0 deletions
diff --git a/absl/time/format.cc b/absl/time/format.cc
new file mode 100644
index 000000000000..c58a886bf93a
--- /dev/null
+++ b/absl/time/format.cc
@@ -0,0 +1,140 @@
+// Copyright 2017 The Abseil Authors.
+//
+// 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.
+
+#include <string.h>
+#include <cctype>
+#include <cstdint>
+
+#include "absl/time/time.h"
+#include "cctz/time_zone.h"
+
+namespace absl {
+
+extern const char RFC3339_full[] = "%Y-%m-%dT%H:%M:%E*S%Ez";
+extern const char RFC3339_sec[] =  "%Y-%m-%dT%H:%M:%S%Ez";
+
+extern const char RFC1123_full[] = "%a, %d %b %E4Y %H:%M:%S %z";
+extern const char RFC1123_no_wday[] =  "%d %b %E4Y %H:%M:%S %z";
+
+namespace {
+
+const char kInfiniteFutureStr[] = "infinite-future";
+const char kInfinitePastStr[] = "infinite-past";
+
+using cctz_sec = cctz::time_point<cctz::sys_seconds>;
+using cctz_fem = cctz::detail::femtoseconds;
+struct cctz_parts {
+  cctz_sec sec;
+  cctz_fem fem;
+};
+
+inline cctz_sec unix_epoch() {
+  return std::chrono::time_point_cast<cctz::sys_seconds>(
+      std::chrono::system_clock::from_time_t(0));
+}
+
+// Splits a Time into seconds and femtoseconds, which can be used with CCTZ.
+// Requires that 't' is finite. See duration.cc for details about rep_hi and
+// rep_lo.
+cctz_parts Split(absl::Time t) {
+  const auto d = time_internal::ToUnixDuration(t);
+  const int64_t rep_hi = time_internal::GetRepHi(d);
+  const int64_t rep_lo = time_internal::GetRepLo(d);
+  const auto sec = unix_epoch() + cctz::sys_seconds(rep_hi);
+  const auto fem = cctz_fem(rep_lo * (1000 * 1000 / 4));
+  return {sec, fem};
+}
+
+// Joins the given seconds and femtoseconds into a Time. See duration.cc for
+// details about rep_hi and rep_lo.
+absl::Time Join(const cctz_parts& parts) {
+  const int64_t rep_hi = (parts.sec - unix_epoch()).count();
+  const uint32_t rep_lo = parts.fem.count() / (1000 * 1000 / 4);
+  const auto d = time_internal::MakeDuration(rep_hi, rep_lo);
+  return time_internal::FromUnixDuration(d);
+}
+
+}  // namespace
+
+std::string FormatTime(const std::string& format, absl::Time t, absl::TimeZone tz) {
+  if (t == absl::InfiniteFuture()) return kInfiniteFutureStr;
+  if (t == absl::InfinitePast()) return kInfinitePastStr;
+  const auto parts = Split(t);
+  return cctz::detail::format(format, parts.sec, parts.fem,
+                              cctz::time_zone(tz));
+}
+
+std::string FormatTime(absl::Time t, absl::TimeZone tz) {
+  return FormatTime(RFC3339_full, t, tz);
+}
+
+std::string FormatTime(absl::Time t) {
+  return absl::FormatTime(RFC3339_full, t, absl::LocalTimeZone());
+}
+
+bool ParseTime(const std::string& format, const std::string& input, absl::Time* time,
+               std::string* err) {
+  return absl::ParseTime(format, input, absl::UTCTimeZone(), time, err);
+}
+
+// If the input std::string does not contain an explicit UTC offset, interpret
+// the fields with respect to the given TimeZone.
+bool ParseTime(const std::string& format, const std::string& input, absl::TimeZone tz,
+               absl::Time* time, std::string* err) {
+  const char* data = input.c_str();
+  while (std::isspace(*data)) ++data;
+
+  size_t inf_size = strlen(kInfiniteFutureStr);
+  if (strncmp(data, kInfiniteFutureStr, inf_size) == 0) {
+    const char* new_data = data + inf_size;
+    while (std::isspace(*new_data)) ++new_data;
+    if (*new_data == '\0') {
+      *time = InfiniteFuture();
+      return true;
+    }
+  }
+
+  inf_size = strlen(kInfinitePastStr);
+  if (strncmp(data, kInfinitePastStr, inf_size) == 0) {
+    const char* new_data = data + inf_size;
+    while (std::isspace(*new_data)) ++new_data;
+    if (*new_data == '\0') {
+      *time = InfinitePast();
+      return true;
+    }
+  }
+
+  std::string error;
+  cctz_parts parts;
+  const bool b = cctz::detail::parse(format, input, cctz::time_zone(tz),
+                                     &parts.sec, &parts.fem, &error);
+  if (b) {
+    *time = Join(parts);
+  } else if (err != nullptr) {
+    *err = error;
+  }
+  return b;
+}
+
+// TODO(b/63899288) copybara strip once dependencies are removed.
+// Functions required to support absl::Time flags. See go/flags.
+bool ParseFlag(const std::string& text, absl::Time* t, std::string* error) {
+  return absl::ParseTime(RFC3339_full, text, absl::UTCTimeZone(), t, error);
+}
+
+std::string UnparseFlag(absl::Time t) {
+  return absl::FormatTime(RFC3339_full, t, absl::UTCTimeZone());
+}
+
+}  // namespace absl