Line data Source code
1 : /*
2 : * The MIT License (MIT)
3 : *
4 : * Copyright (c) 2015-2021 Derick Rethans
5 : * Copyright (c) 2021 MongoDB
6 : *
7 : * Permission is hereby granted, free of charge, to any person obtaining a copy
8 : * of this software and associated documentation files (the "Software"), to deal
9 : * in the Software without restriction, including without limitation the rights
10 : * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 : * copies of the Software, and to permit persons to whom the Software is
12 : * furnished to do so, subject to the following conditions:
13 : *
14 : * The above copyright notice and this permission notice shall be included in
15 : * all copies or substantial portions of the Software.
16 : *
17 : * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 : * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 : * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 : * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 : * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 : * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23 : * THE SOFTWARE.
24 : */
25 :
26 : #include "timelib.h"
27 : #include "timelib_private.h"
28 :
29 692 : void timelib_unixtime2date(timelib_sll ts, timelib_sll *y, timelib_sll *m, timelib_sll *d)
30 : {
31 : timelib_sll days, era, t;
32 : timelib_ull day_of_era, year_of_era, day_of_year, month_portion;
33 :
34 : /* Calculate days since algorithm's epoch (0000-03-01) */
35 692 : days = ts / SECS_PER_DAY + HINNANT_EPOCH_SHIFT;
36 :
37 : /* Adjustment for a negative time portion */
38 692 : t = ts % SECS_PER_DAY;
39 692 : days += (t < 0) ? -1 : 0;
40 :
41 : /* Calculate year, month, and day. Algorithm from:
42 : * http://howardhinnant.github.io/date_algorithms.html#civil_from_days */
43 692 : era = (days >= 0 ? days : days - DAYS_PER_ERA + 1) / DAYS_PER_ERA;
44 692 : day_of_era = days - era * DAYS_PER_ERA;
45 692 : year_of_era = (day_of_era - day_of_era / 1460 + day_of_era / 36524 - day_of_era / 146096) / DAYS_PER_YEAR;
46 692 : *y = year_of_era + era * YEARS_PER_ERA;
47 692 : day_of_year = day_of_era - (DAYS_PER_YEAR * year_of_era + year_of_era / 4 - year_of_era / 100);
48 692 : month_portion = (5 * day_of_year + 2) / 153;
49 692 : *d = day_of_year - (153 * month_portion + 2) / 5 + 1;
50 692 : *m = month_portion + (month_portion < 10 ? 3 : -9);
51 692 : *y += (*m <= 2);
52 :
53 : TIMELIB_DEBUG(printf("A: ts=%lld, year=%lld, month=%lld, day=%lld,", ts, *y, *m, *d););
54 692 : }
55 :
56 : /* Converts a Unix timestamp value into broken down time, in GMT */
57 692 : void timelib_unixtime2gmt(timelib_time* tm, timelib_sll ts)
58 : {
59 : timelib_sll remainder;
60 : timelib_sll hours, minutes, seconds;
61 :
62 692 : timelib_unixtime2date(ts, &tm->y, &tm->m, &tm->d);
63 692 : remainder = ts % SECS_PER_DAY;
64 692 : remainder += (remainder < 0) * SECS_PER_DAY;
65 :
66 : /* That was the date, now we do the time */
67 692 : hours = remainder / 3600;
68 692 : minutes = (remainder - hours * 3600) / 60;
69 692 : seconds = remainder % 60;
70 : TIMELIB_DEBUG(printf(" hour=%lld, minute=%lld, second=%lld\n", hours, minutes, seconds););
71 :
72 692 : tm->h = hours;
73 692 : tm->i = minutes;
74 692 : tm->s = seconds;
75 692 : tm->z = 0;
76 692 : tm->dst = 0;
77 692 : tm->sse = ts;
78 692 : tm->sse_uptodate = 1;
79 692 : tm->tim_uptodate = 1;
80 692 : tm->is_localtime = 0;
81 692 : }
82 :
83 368 : void timelib_update_from_sse(timelib_time *tm)
84 : {
85 : timelib_sll sse;
86 368 : int z = tm->z;
87 368 : signed int dst = tm->dst;
88 :
89 368 : sse = tm->sse;
90 :
91 368 : switch (tm->zone_type) {
92 0 : case TIMELIB_ZONETYPE_ABBR:
93 : case TIMELIB_ZONETYPE_OFFSET: {
94 0 : timelib_unixtime2gmt(tm, tm->sse + tm->z + (tm->dst * 3600));
95 :
96 0 : goto cleanup;
97 : }
98 :
99 128 : case TIMELIB_ZONETYPE_ID: {
100 128 : int32_t offset = 0;
101 :
102 128 : timelib_get_time_zone_offset_info(tm->sse, tm->tz_info, &offset, NULL, NULL);
103 128 : timelib_unixtime2gmt(tm, tm->sse + offset);
104 :
105 128 : goto cleanup;
106 : }
107 :
108 240 : default:
109 240 : timelib_unixtime2gmt(tm, tm->sse);
110 240 : goto cleanup;
111 : }
112 368 : cleanup:
113 368 : tm->sse = sse;
114 368 : tm->is_localtime = 1;
115 368 : tm->have_zone = 1;
116 368 : tm->z = z;
117 368 : tm->dst = dst;
118 368 : }
119 :
120 84 : void timelib_unixtime2local(timelib_time *tm, timelib_sll ts)
121 : {
122 : timelib_time_offset *gmt_offset;
123 84 : timelib_tzinfo *tz = tm->tz_info;
124 :
125 84 : switch (tm->zone_type) {
126 0 : case TIMELIB_ZONETYPE_ABBR:
127 : case TIMELIB_ZONETYPE_OFFSET: {
128 0 : int z = tm->z;
129 0 : signed int dst = tm->dst;
130 :
131 0 : timelib_unixtime2gmt(tm, ts + tm->z + (tm->dst * 3600));
132 :
133 0 : tm->sse = ts;
134 0 : tm->z = z;
135 0 : tm->dst = dst;
136 0 : break;
137 : }
138 :
139 84 : case TIMELIB_ZONETYPE_ID:
140 84 : gmt_offset = timelib_get_time_zone_info(ts, tz);
141 84 : timelib_unixtime2gmt(tm, ts + gmt_offset->offset);
142 :
143 : /* we need to reset the sse here as unixtime2gmt modifies it */
144 84 : tm->sse = ts;
145 84 : tm->dst = gmt_offset->is_dst;
146 84 : tm->z = gmt_offset->offset;
147 84 : tm->tz_info = tz;
148 :
149 84 : timelib_time_tz_abbr_update(tm, gmt_offset->abbr);
150 84 : timelib_time_offset_dtor(gmt_offset);
151 84 : break;
152 :
153 0 : default:
154 0 : tm->is_localtime = 0;
155 0 : tm->have_zone = 0;
156 0 : return;
157 : }
158 :
159 84 : tm->is_localtime = 1;
160 84 : tm->have_zone = 1;
161 : }
162 :
163 0 : void timelib_set_timezone_from_offset(timelib_time *t, timelib_sll utc_offset)
164 : {
165 0 : if (t->tz_abbr) {
166 0 : timelib_free(t->tz_abbr);
167 : }
168 0 : t->tz_abbr = NULL;
169 :
170 0 : t->z = utc_offset;
171 0 : t->have_zone = 1;
172 0 : t->zone_type = TIMELIB_ZONETYPE_OFFSET;
173 0 : t->dst = 0;
174 0 : t->tz_info = NULL;
175 0 : }
176 :
177 0 : void timelib_set_timezone_from_abbr(timelib_time *t, timelib_abbr_info abbr_info)
178 : {
179 0 : if (t->tz_abbr) {
180 0 : timelib_free(t->tz_abbr);
181 : }
182 0 : t->tz_abbr = timelib_strdup(abbr_info.abbr);
183 :
184 0 : t->z = abbr_info.utc_offset;
185 0 : t->have_zone = 1;
186 0 : t->zone_type = TIMELIB_ZONETYPE_ABBR;
187 0 : t->dst = abbr_info.dst;
188 0 : t->tz_info = NULL;
189 0 : }
190 :
191 424 : void timelib_set_timezone(timelib_time *t, timelib_tzinfo *tz)
192 : {
193 : timelib_time_offset *gmt_offset;
194 :
195 424 : gmt_offset = timelib_get_time_zone_info(t->sse, tz);
196 424 : t->z = gmt_offset->offset;
197 : /*
198 : if (t->dst != gmt_offset->is_dst) {
199 : printf("ERROR (%d, %d)\n", t->dst, gmt_offset->is_dst);
200 : exit(1);
201 : }
202 : */
203 424 : t->dst = gmt_offset->is_dst;
204 424 : t->tz_info = tz;
205 424 : if (t->tz_abbr) {
206 340 : timelib_free(t->tz_abbr);
207 : }
208 424 : t->tz_abbr = timelib_strdup(gmt_offset->abbr);
209 424 : timelib_time_offset_dtor(gmt_offset);
210 :
211 424 : t->have_zone = 1;
212 424 : t->zone_type = TIMELIB_ZONETYPE_ID;
213 424 : }
214 :
215 : /* Converts the time stored in the struct to localtime if localtime = true,
216 : * otherwise it converts it to gmttime. This is only done when necessary
217 : * of course. */
218 0 : int timelib_apply_localtime(timelib_time *t, unsigned int localtime)
219 : {
220 0 : if (localtime) {
221 : /* Converting from GMT time to local time */
222 : TIMELIB_DEBUG(printf("Converting from GMT time to local time\n"););
223 :
224 : /* Check if TZ is set */
225 0 : if (!t->tz_info) {
226 : TIMELIB_DEBUG(printf("E: No timezone configured, can't switch to local time\n"););
227 0 : return -1;
228 : }
229 :
230 0 : timelib_unixtime2local(t, t->sse);
231 : } else {
232 : /* Converting from local time to GMT time */
233 : TIMELIB_DEBUG(printf("Converting from local time to GMT time\n"););
234 :
235 0 : timelib_unixtime2gmt(t, t->sse);
236 : }
237 0 : return 0;
238 : }
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