// Copyright 2018 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
//
// 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.
#include "absl/time/civil_time.h"
#include <cstdlib>
#include <string>
#include "absl/strings/str_cat.h"
#include "absl/time/time.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace {
// Since a civil time has a larger year range than absl::Time (64-bit years vs
// 64-bit seconds, respectively) we normalize years to roughly +/- 400 years
// around the year 2400, which will produce an equivalent year in a range that
// absl::Time can handle.
inline civil_year_t NormalizeYear(civil_year_t year) {
return 2400 + year % 400;
}
// Formats the given CivilSecond according to the given format.
std::string FormatYearAnd(string_view fmt, CivilSecond cs) {
const CivilSecond ncs(NormalizeYear(cs.year()), cs.month(), cs.day(),
cs.hour(), cs.minute(), cs.second());
const TimeZone utc = UTCTimeZone();
// TODO(absl-team): Avoid conversion of fmt string.
return StrCat(cs.year(),
FormatTime(std::string(fmt), FromCivil(ncs, utc), utc));
}
template <typename CivilT>
bool ParseYearAnd(string_view fmt, string_view s, CivilT* c) {
// Civil times support a larger year range than absl::Time, so we need to
// parse the year separately, normalize it, then use absl::ParseTime on the
// normalized string.
const std::string ss = std::string(s); // TODO(absl-team): Avoid conversion.
const char* const np = ss.c_str();
char* endp;
errno = 0;
const civil_year_t y =
std::strtoll(np, &endp, 10); // NOLINT(runtime/deprecated_fn)
if (endp == np || errno == ERANGE) return false;
const std::string norm = StrCat(NormalizeYear(y), endp);
const TimeZone utc = UTCTimeZone();
Time t;
if (ParseTime(StrCat("%Y", fmt), norm, utc, &t, nullptr)) {
const auto cs = ToCivilSecond(t, utc);
*c = CivilT(y, cs.month(), cs.day(), cs.hour(), cs.minute(), cs.second());
return true;
}
return false;
}
// Tries to parse the type as a CivilT1, but then assigns the result to the
// argument of type CivilT2.
template <typename CivilT1, typename CivilT2>
bool ParseAs(string_view s, CivilT2* c) {
CivilT1 t1;
if (ParseCivilTime(s, &t1)) {
*c = CivilT2(t1);
return true;
}
return false;
}
template <typename CivilT>
bool ParseLenient(string_view s, CivilT* c) {
// A fastpath for when the given string data parses exactly into the given
// type T (e.g., s="YYYY-MM-DD" and CivilT=CivilDay).
if (ParseCivilTime(s, c)) return true;
// Try parsing as each of the 6 types, trying the most common types first
// (based on csearch results).
if (ParseAs<CivilDay>(s, c)) return true;
if (ParseAs<CivilSecond>(s, c)) return true;
if (ParseAs<CivilHour>(s, c)) return true;
if (ParseAs<CivilMonth>(s, c)) return true;
if (ParseAs<CivilMinute>(s, c)) return true;
if (ParseAs<CivilYear>(s, c)) return true;
return false;
}
} // namespace
std::string FormatCivilTime(CivilSecond c) {
return FormatYearAnd("-%m-%d%ET%H:%M:%S", c);
}
std::string FormatCivilTime(CivilMinute c) {
return FormatYearAnd("-%m-%d%ET%H:%M", c);
}
std::string FormatCivilTime(CivilHour c) {
return FormatYearAnd("-%m-%d%ET%H", c);
}
std::string FormatCivilTime(CivilDay c) { return FormatYearAnd("-%m-%d", c); }
std::string FormatCivilTime(CivilMonth c) { return FormatYearAnd("-%m", c); }
std::string FormatCivilTime(CivilYear c) { return FormatYearAnd("", c); }
bool ParseCivilTime(string_view s, CivilSecond* c) {
return ParseYearAnd("-%m-%d%ET%H:%M:%S", s, c);
}
bool ParseCivilTime(string_view s, CivilMinute* c) {
return ParseYearAnd("-%m-%d%ET%H:%M", s, c);
}
bool ParseCivilTime(string_view s, CivilHour* c) {
return ParseYearAnd("-%m-%d%ET%H", s, c);
}
bool ParseCivilTime(string_view s, CivilDay* c) {
return ParseYearAnd("-%m-%d", s, c);
}
bool ParseCivilTime(string_view s, CivilMonth* c) {
return ParseYearAnd("-%m", s, c);
}
bool ParseCivilTime(string_view s, CivilYear* c) {
return ParseYearAnd("", s, c);
}
bool ParseLenientCivilTime(string_view s, CivilSecond* c) {
return ParseLenient(s, c);
}
bool ParseLenientCivilTime(string_view s, CivilMinute* c) {
return ParseLenient(s, c);
}
bool ParseLenientCivilTime(string_view s, CivilHour* c) {
return ParseLenient(s, c);
}
bool ParseLenientCivilTime(string_view s, CivilDay* c) {
return ParseLenient(s, c);
}
bool ParseLenientCivilTime(string_view s, CivilMonth* c) {
return ParseLenient(s, c);
}
bool ParseLenientCivilTime(string_view s, CivilYear* c) {
return ParseLenient(s, c);
}
namespace time_internal {
std::ostream& operator<<(std::ostream& os, CivilYear y) {
return os << FormatCivilTime(y);
}
std::ostream& operator<<(std::ostream& os, CivilMonth m) {
return os << FormatCivilTime(m);
}
std::ostream& operator<<(std::ostream& os, CivilDay d) {
return os << FormatCivilTime(d);
}
std::ostream& operator<<(std::ostream& os, CivilHour h) {
return os << FormatCivilTime(h);
}
std::ostream& operator<<(std::ostream& os, CivilMinute m) {
return os << FormatCivilTime(m);
}
std::ostream& operator<<(std::ostream& os, CivilSecond s) {
return os << FormatCivilTime(s);
}
} // namespace time_internal
ABSL_NAMESPACE_END
} // namespace absl
