1// Copyright 2017 The Abseil Authors.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// https://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#include <string.h>
16#include <cctype>
17#include <cstdint>
18
19#include "absl/time/internal/cctz/include/cctz/time_zone.h"
20#include "absl/time/time.h"
21
22namespace cctz = absl::time_internal::cctz;
23
24namespace absl {
25
26extern const char RFC3339_full[] = "%Y-%m-%dT%H:%M:%E*S%Ez";
27extern const char RFC3339_sec[] = "%Y-%m-%dT%H:%M:%S%Ez";
28
29extern const char RFC1123_full[] = "%a, %d %b %E4Y %H:%M:%S %z";
30extern const char RFC1123_no_wday[] = "%d %b %E4Y %H:%M:%S %z";
31
32namespace {
33
34const char kInfiniteFutureStr[] = "infinite-future";
35const char kInfinitePastStr[] = "infinite-past";
36
37struct cctz_parts {
38 cctz::time_point<cctz::seconds> sec;
39 cctz::detail::femtoseconds fem;
40};
41
42inline cctz::time_point<cctz::seconds> unix_epoch() {
43 return std::chrono::time_point_cast<cctz::seconds>(
44 std::chrono::system_clock::from_time_t(0));
45}
46
47// Splits a Time into seconds and femtoseconds, which can be used with CCTZ.
48// Requires that 't' is finite. See duration.cc for details about rep_hi and
49// rep_lo.
50cctz_parts Split(absl::Time t) {
51 const auto d = time_internal::ToUnixDuration(t);
52 const int64_t rep_hi = time_internal::GetRepHi(d);
53 const int64_t rep_lo = time_internal::GetRepLo(d);
54 const auto sec = unix_epoch() + cctz::seconds(rep_hi);
55 const auto fem = cctz::detail::femtoseconds(rep_lo * (1000 * 1000 / 4));
56 return {sec, fem};
57}
58
59// Joins the given seconds and femtoseconds into a Time. See duration.cc for
60// details about rep_hi and rep_lo.
61absl::Time Join(const cctz_parts& parts) {
62 const int64_t rep_hi = (parts.sec - unix_epoch()).count();
63 const uint32_t rep_lo = parts.fem.count() / (1000 * 1000 / 4);
64 const auto d = time_internal::MakeDuration(rep_hi, rep_lo);
65 return time_internal::FromUnixDuration(d);
66}
67
68} // namespace
69
70std::string FormatTime(const std::string& format, absl::Time t,
71 absl::TimeZone tz) {
72 if (t == absl::InfiniteFuture()) return kInfiniteFutureStr;
73 if (t == absl::InfinitePast()) return kInfinitePastStr;
74 const auto parts = Split(t);
75 return cctz::detail::format(format, parts.sec, parts.fem,
76 cctz::time_zone(tz));
77}
78
79std::string FormatTime(absl::Time t, absl::TimeZone tz) {
80 return FormatTime(RFC3339_full, t, tz);
81}
82
83std::string FormatTime(absl::Time t) {
84 return absl::FormatTime(RFC3339_full, t, absl::LocalTimeZone());
85}
86
87bool ParseTime(const std::string& format, const std::string& input,
88 absl::Time* time, std::string* err) {
89 return absl::ParseTime(format, input, absl::UTCTimeZone(), time, err);
90}
91
92// If the input string does not contain an explicit UTC offset, interpret
93// the fields with respect to the given TimeZone.
94bool ParseTime(const std::string& format, const std::string& input,
95 absl::TimeZone tz, absl::Time* time, std::string* err) {
96 const char* data = input.c_str();
97 while (std::isspace(*data)) ++data;
98
99 size_t inf_size = strlen(kInfiniteFutureStr);
100 if (strncmp(data, kInfiniteFutureStr, inf_size) == 0) {
101 const char* new_data = data + inf_size;
102 while (std::isspace(*new_data)) ++new_data;
103 if (*new_data == '\0') {
104 *time = InfiniteFuture();
105 return true;
106 }
107 }
108
109 inf_size = strlen(kInfinitePastStr);
110 if (strncmp(data, kInfinitePastStr, inf_size) == 0) {
111 const char* new_data = data + inf_size;
112 while (std::isspace(*new_data)) ++new_data;
113 if (*new_data == '\0') {
114 *time = InfinitePast();
115 return true;
116 }
117 }
118
119 std::string error;
120 cctz_parts parts;
121 const bool b = cctz::detail::parse(format, input, cctz::time_zone(tz),
122 &parts.sec, &parts.fem, &error);
123 if (b) {
124 *time = Join(parts);
125 } else if (err != nullptr) {
126 *err = error;
127 }
128 return b;
129}
130
131// Functions required to support absl::Time flags.
132bool ParseFlag(const std::string& text, absl::Time* t, std::string* error) {
133 return absl::ParseTime(RFC3339_full, text, absl::UTCTimeZone(), t, error);
134}
135
136std::string UnparseFlag(absl::Time t) {
137 return absl::FormatTime(RFC3339_full, t, absl::UTCTimeZone());
138}
139
140} // namespace absl
141