summaryrefslogtreecommitdiff
path: root/absl/time/format.cc
blob: a3671510411c88660fe3df0a93a419677c394ca4 (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
// 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/internal/cctz/include/cctz/time_zone.h"
#include "absl/time/time.h"

namespace cctz = absl::time_internal::cctz;

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";

struct cctz_parts {
  cctz::time_point<cctz::seconds> sec;
  cctz::detail::femtoseconds fem;
};

inline cctz::time_point<cctz::seconds> unix_epoch() {
  return std::chrono::time_point_cast<cctz::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::seconds(rep_hi);
  const auto fem = cctz::detail::femtoseconds(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 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;
}

// Functions required to support absl::Time 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