summaryrefslogtreecommitdiff
path: root/absl/time/civil_time.cc
blob: bdfe9ce0efb35e44fab0e6b6cfbcc85268619cff (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
// 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