1 /*
2 * The MIT License (MIT)
3 *
4 * Copyright (c) 2015-2019 Derick Rethans
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "timelib.h"
26 #include "timelib_private.h"
27
28 static int month_tab_leap[12] = { -1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
29 static int month_tab[12] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
30
31
32 /* Converts a Unix timestamp value into broken down time, in GMT */
timelib_unixtime2gmt(timelib_time * tm,timelib_sll ts)33 void timelib_unixtime2gmt(timelib_time* tm, timelib_sll ts)
34 {
35 timelib_sll days, remainder, tmp_days;
36 timelib_sll cur_year = 1970;
37 timelib_sll i;
38 timelib_sll hours, minutes, seconds;
39 int *months;
40
41 days = ts / SECS_PER_DAY;
42 remainder = ts - (days * SECS_PER_DAY);
43 if (ts < 0 && remainder == 0) {
44 days++;
45 remainder -= SECS_PER_DAY;
46 }
47 TIMELIB_DEBUG(printf("days=%lld, rem=%lld\n", days, remainder););
48
49 if (ts >= 0) {
50 tmp_days = days + 1;
51 } else {
52 tmp_days = days;
53 }
54
55 if (tmp_days > DAYS_PER_LYEAR_PERIOD || tmp_days <= -DAYS_PER_LYEAR_PERIOD) {
56 cur_year += YEARS_PER_LYEAR_PERIOD * (tmp_days / DAYS_PER_LYEAR_PERIOD);
57 tmp_days -= DAYS_PER_LYEAR_PERIOD * (tmp_days / DAYS_PER_LYEAR_PERIOD);
58 }
59 TIMELIB_DEBUG(printf("tmp_days=%lld, year=%lld\n", tmp_days, cur_year););
60
61 if (ts >= 0) {
62 while (tmp_days >= DAYS_PER_LYEAR) {
63 cur_year++;
64 if (timelib_is_leap(cur_year)) {
65 tmp_days -= DAYS_PER_LYEAR;
66 } else {
67 tmp_days -= DAYS_PER_YEAR;
68 }
69 TIMELIB_DEBUG(printf("tmp_days=%lld, year=%lld\n", tmp_days, cur_year););
70 }
71 } else {
72 while (tmp_days <= 0) {
73 cur_year--;
74 if (timelib_is_leap(cur_year)) {
75 tmp_days += DAYS_PER_LYEAR;
76 } else {
77 tmp_days += DAYS_PER_YEAR;
78 }
79 TIMELIB_DEBUG(printf("tmp_days=%lld, year=%lld\n", tmp_days, cur_year););
80 }
81 remainder += SECS_PER_DAY;
82 }
83 TIMELIB_DEBUG(printf("tmp_days=%lld, year=%lld\n", tmp_days, cur_year););
84
85 months = timelib_is_leap(cur_year) ? month_tab_leap : month_tab;
86 if (timelib_is_leap(cur_year) && cur_year < 1970) {
87 tmp_days--;
88 }
89 i = 11;
90 while (i > 0) {
91 TIMELIB_DEBUG(printf("month=%lld (%d)\n", i, months[i]););
92 if (tmp_days > months[i]) {
93 break;
94 }
95 i--;
96 }
97 TIMELIB_DEBUG(printf("A: ts=%lld, year=%lld, month=%lld, day=%lld,", ts, cur_year, i + 1, tmp_days - months[i]););
98
99 /* That was the date, now we do the time */
100 hours = remainder / 3600;
101 minutes = (remainder - hours * 3600) / 60;
102 seconds = remainder % 60;
103 TIMELIB_DEBUG(printf(" hour=%lld, minute=%lld, second=%lld\n", hours, minutes, seconds););
104
105 tm->y = cur_year;
106 tm->m = i + 1;
107 tm->d = tmp_days - months[i];
108 tm->h = hours;
109 tm->i = minutes;
110 tm->s = seconds;
111 tm->z = 0;
112 tm->dst = 0;
113 tm->sse = ts;
114 tm->sse_uptodate = 1;
115 tm->tim_uptodate = 1;
116 tm->is_localtime = 0;
117 }
118
timelib_update_from_sse(timelib_time * tm)119 void timelib_update_from_sse(timelib_time *tm)
120 {
121 timelib_sll sse;
122 int z = tm->z;
123 signed int dst = tm->dst;
124
125 sse = tm->sse;
126
127 switch (tm->zone_type) {
128 case TIMELIB_ZONETYPE_ABBR:
129 case TIMELIB_ZONETYPE_OFFSET: {
130 timelib_unixtime2gmt(tm, tm->sse + tm->z + (tm->dst * 3600));
131
132 goto cleanup;
133 }
134
135 case TIMELIB_ZONETYPE_ID: {
136 timelib_time_offset *gmt_offset;
137
138 gmt_offset = timelib_get_time_zone_info(tm->sse, tm->tz_info);
139 timelib_unixtime2gmt(tm, tm->sse + gmt_offset->offset);
140 timelib_time_offset_dtor(gmt_offset);
141
142 goto cleanup;
143 }
144
145 default:
146 timelib_unixtime2gmt(tm, tm->sse);
147 goto cleanup;
148 }
149 cleanup:
150 tm->sse = sse;
151 tm->is_localtime = 1;
152 tm->have_zone = 1;
153 tm->z = z;
154 tm->dst = dst;
155 }
156
timelib_unixtime2local(timelib_time * tm,timelib_sll ts)157 void timelib_unixtime2local(timelib_time *tm, timelib_sll ts)
158 {
159 timelib_time_offset *gmt_offset;
160 timelib_tzinfo *tz = tm->tz_info;
161
162 switch (tm->zone_type) {
163 case TIMELIB_ZONETYPE_ABBR:
164 case TIMELIB_ZONETYPE_OFFSET: {
165 int z = tm->z;
166 signed int dst = tm->dst;
167
168 timelib_unixtime2gmt(tm, ts + tm->z + (tm->dst * 3600));
169
170 tm->sse = ts;
171 tm->z = z;
172 tm->dst = dst;
173 break;
174 }
175
176 case TIMELIB_ZONETYPE_ID:
177 gmt_offset = timelib_get_time_zone_info(ts, tz);
178 timelib_unixtime2gmt(tm, ts + gmt_offset->offset);
179
180 /* we need to reset the sse here as unixtime2gmt modifies it */
181 tm->sse = ts;
182 tm->dst = gmt_offset->is_dst;
183 tm->z = gmt_offset->offset;
184 tm->tz_info = tz;
185
186 timelib_time_tz_abbr_update(tm, gmt_offset->abbr);
187 timelib_time_offset_dtor(gmt_offset);
188 break;
189
190 default:
191 tm->is_localtime = 0;
192 tm->have_zone = 0;
193 return;
194 }
195
196 tm->is_localtime = 1;
197 tm->have_zone = 1;
198 }
199
timelib_set_timezone_from_offset(timelib_time * t,timelib_sll utc_offset)200 void timelib_set_timezone_from_offset(timelib_time *t, timelib_sll utc_offset)
201 {
202 if (t->tz_abbr) {
203 timelib_free(t->tz_abbr);
204 }
205 t->tz_abbr = NULL;
206
207 t->z = utc_offset;
208 t->have_zone = 1;
209 t->zone_type = TIMELIB_ZONETYPE_OFFSET;
210 t->dst = 0;
211 t->tz_info = NULL;
212 }
213
timelib_set_timezone_from_abbr(timelib_time * t,timelib_abbr_info abbr_info)214 void timelib_set_timezone_from_abbr(timelib_time *t, timelib_abbr_info abbr_info)
215 {
216 if (t->tz_abbr) {
217 timelib_free(t->tz_abbr);
218 }
219 t->tz_abbr = timelib_strdup(abbr_info.abbr);
220
221 t->z = abbr_info.utc_offset;
222 t->have_zone = 1;
223 t->zone_type = TIMELIB_ZONETYPE_ABBR;
224 t->dst = abbr_info.dst;
225 t->tz_info = NULL;
226 }
227
timelib_set_timezone(timelib_time * t,timelib_tzinfo * tz)228 void timelib_set_timezone(timelib_time *t, timelib_tzinfo *tz)
229 {
230 timelib_time_offset *gmt_offset;
231
232 gmt_offset = timelib_get_time_zone_info(t->sse, tz);
233 t->z = gmt_offset->offset;
234 /*
235 if (t->dst != gmt_offset->is_dst) {
236 printf("ERROR (%d, %d)\n", t->dst, gmt_offset->is_dst);
237 exit(1);
238 }
239 */
240 t->dst = gmt_offset->is_dst;
241 t->tz_info = tz;
242 if (t->tz_abbr) {
243 timelib_free(t->tz_abbr);
244 }
245 t->tz_abbr = timelib_strdup(gmt_offset->abbr);
246 timelib_time_offset_dtor(gmt_offset);
247
248 t->have_zone = 1;
249 t->zone_type = TIMELIB_ZONETYPE_ID;
250 }
251
252 /* Converts the time stored in the struct to localtime if localtime = true,
253 * otherwise it converts it to gmttime. This is only done when necessary
254 * of course. */
timelib_apply_localtime(timelib_time * t,unsigned int localtime)255 int timelib_apply_localtime(timelib_time *t, unsigned int localtime)
256 {
257 if (localtime) {
258 /* Converting from GMT time to local time */
259 TIMELIB_DEBUG(printf("Converting from GMT time to local time\n"););
260
261 /* Check if TZ is set */
262 if (!t->tz_info) {
263 TIMELIB_DEBUG(printf("E: No timezone configured, can't switch to local time\n"););
264 return -1;
265 }
266
267 timelib_unixtime2local(t, t->sse);
268 } else {
269 /* Converting from local time to GMT time */
270 TIMELIB_DEBUG(printf("Converting from local time to GMT time\n"););
271
272 timelib_unixtime2gmt(t, t->sse);
273 }
274 return 0;
275 }
276
