Always give mktime a timeval with tm_isdst set to -1, otherwise
things get a bit out-of-phase when we step backwards 1 hour from between 0:00 and 1:00 on the first of the month following the transition into Summer time. This is probably actually a bug in mktime(). PR: 10963 If mktime() fails and 68 < year < 138, assume that the reason is because of Summer time and adjust up or down according to our adjusting context by one hour. This assumes that all DSTs are multiples of 1 hour. PR: 6223, 17750
This commit is contained in:
parent
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commit
a625bfec63
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=59022
181
bin/date/vary.c
181
bin/date/vary.c
@ -53,6 +53,28 @@ static struct trans trans_wday[] = {
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};
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static char digits[] = "0123456789";
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static int adjhour(struct tm *, char, int);
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static int
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domktime(struct tm *t, char type)
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{
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int ret;
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/*
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* Don't let mktime have a specific tm_isdst value. If we do,
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* it gets confused when we ``vary'' in and out of Summer time
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*/
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t->tm_isdst = -1;
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if ((ret = mktime(t)) == -1 && t->tm_year > 68 && t->tm_year < 138)
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/*
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* If mktime() fails, adjust by an hour. If we're actually
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* bridging a savings of several hours, we'll recurse several
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* times.
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*/
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ret = adjhour(t, type == '-' ? type : '+', 1);
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return ret;
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}
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static int
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trans(const struct trans t[], const char *arg)
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@ -129,7 +151,7 @@ adjyear(struct tm *t, char type, int val)
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t->tm_year -= 1900; /* struct tm holds years since 1900 */
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break;
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}
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return mktime(t) != -1;
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return domktime(t, type) != -1;
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}
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static int
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@ -146,12 +168,14 @@ adjmon(struct tm *t, char type, int val, int istext)
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else
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val -= t->tm_mon + 1; /* later this year */
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}
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if (!adjyear(t, '+', (t->tm_mon + val) / 12))
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return 0;
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val %= 12;
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t->tm_mon += val;
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if (t->tm_mon > 11)
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t->tm_mon -= 12;
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if (val) {
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if (!adjyear(t, '+', (t->tm_mon + val) / 12))
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return 0;
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val %= 12;
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t->tm_mon += val;
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if (t->tm_mon > 11)
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t->tm_mon -= 12;
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}
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break;
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case '-':
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@ -161,15 +185,17 @@ adjmon(struct tm *t, char type, int val, int istext)
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else
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val = t->tm_mon - val + 1; /* early this year */
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}
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if (!adjyear(t, '-', val / 12))
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return 0;
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val %= 12;
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if (val > t->tm_mon) {
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if (!adjyear(t, '-', 1))
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if (val) {
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if (!adjyear(t, '-', val / 12))
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return 0;
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val -= 12;
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val %= 12;
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if (val > t->tm_mon) {
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if (!adjyear(t, '-', 1))
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return 0;
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val -= 12;
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}
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t->tm_mon -= val;
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}
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t->tm_mon -= val;
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break;
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default:
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@ -178,13 +204,14 @@ adjmon(struct tm *t, char type, int val, int istext)
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t->tm_mon = --val;
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}
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return mktime(t) != -1;
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return domktime(t, type) != -1;
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}
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static int
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adjday(struct tm *t, char type, int val)
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{
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int mdays;
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switch (type) {
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case '+':
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while (val) {
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@ -221,7 +248,7 @@ adjday(struct tm *t, char type, int val)
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break;
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}
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return mktime(t) != -1;
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return domktime(t, type) != -1;
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}
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static int
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@ -238,17 +265,17 @@ adjwday(struct tm *t, char type, int val, int istext)
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else
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val -= t->tm_wday; /* later this week */
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else
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val *= 7; /* "-W +5" == "5 weeks in the future" */
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return adjday(t, '+', val);
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val *= 7; /* "-v+5w" == "5 weeks in the future" */
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return !val || adjday(t, '+', val);
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case '-':
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if (istext)
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if (istext) {
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if (val > t->tm_wday)
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val = 7 - val + t->tm_wday; /* later last week */
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else
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val = t->tm_wday - val; /* early this week */
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else
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val *= 7; /* "-W -5" == "5 weeks ago" */
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return adjday(t, '-', val);
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} else
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val *= 7; /* "-v-5w" == "5 weeks ago" */
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return !val || adjday(t, '-', val);
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default:
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if (val < t->tm_wday)
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return adjday(t, '-', t->tm_wday - val);
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@ -263,29 +290,47 @@ adjwday(struct tm *t, char type, int val, int istext)
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static int
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adjhour(struct tm *t, char type, int val)
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{
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/*
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* We've got to be careful here in case
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* domktime() calls
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* adjhour() calls
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* adjday() calls
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* domktime() calls
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* adjhour() and recurses forever. It's vital that we've adjusted our
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* number of hours before calling adjday().
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*/
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if (val < 0)
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return 0;
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switch (type) {
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case '+':
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if (!adjday(t, '+', (t->tm_hour + val) / 24))
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return 0;
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val %= 24;
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t->tm_hour += val;
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if (t->tm_hour > 23)
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t->tm_hour -= 24;
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if (val) {
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int days;
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days = (t->tm_hour + val) / 24;
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val %= 24;
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t->tm_hour += val;
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t->tm_hour %= 24;
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if (!adjday(t, '+', days))
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return 0;
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}
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break;
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case '-':
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if (!adjday(t, '-', val / 24))
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return 0;
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val %= 24;
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if (val > t->tm_hour) {
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if (!adjday(t, '-', 1))
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if (val) {
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int days;
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days = val / 24;
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val %= 24;
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if (val > t->tm_hour) {
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days++;
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val -= 24;
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}
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t->tm_hour -= val;
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if (!adjday(t, '-', val / 24))
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return 0;
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val -= 24;
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}
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t->tm_hour -= val;
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break;
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default:
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@ -294,7 +339,7 @@ adjhour(struct tm *t, char type, int val)
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t->tm_hour = val;
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}
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return mktime(t) != -1;
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return domktime(t, type) != -1;
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}
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static int
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@ -305,24 +350,28 @@ adjmin(struct tm *t, char type, int val)
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switch (type) {
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case '+':
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if (!adjhour(t, '+', (t->tm_min + val) / 60))
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return 0;
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val %= 60;
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t->tm_min += val;
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if (t->tm_min > 59)
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t->tm_min -= 60;
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if (val) {
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if (!adjhour(t, '+', (t->tm_min + val) / 60))
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return 0;
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val %= 60;
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t->tm_min += val;
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if (t->tm_min > 59)
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t->tm_min -= 60;
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}
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break;
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case '-':
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if (!adjhour(t, '-', val / 60))
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return 0;
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val %= 60;
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if (val > t->tm_min) {
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if (!adjhour(t, '-', 1))
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if (val) {
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if (!adjhour(t, '-', val / 60))
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return 0;
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val -= 60;
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val %= 60;
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if (val > t->tm_min) {
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if (!adjhour(t, '-', 1))
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return 0;
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val -= 60;
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}
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t->tm_min -= val;
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}
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t->tm_min -= val;
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break;
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default:
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@ -331,7 +380,7 @@ adjmin(struct tm *t, char type, int val)
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t->tm_min = val;
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}
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return mktime(t) != -1;
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return domktime(t, type) != -1;
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}
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static int
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@ -342,24 +391,28 @@ adjsec(struct tm *t, char type, int val)
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switch (type) {
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case '+':
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if (!adjmin(t, '+', (t->tm_sec + val) / 60))
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return 0;
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val %= 60;
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t->tm_sec += val;
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if (t->tm_sec > 59)
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t->tm_sec -= 60;
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if (val) {
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if (!adjmin(t, '+', (t->tm_sec + val) / 60))
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return 0;
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val %= 60;
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t->tm_sec += val;
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if (t->tm_sec > 59)
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t->tm_sec -= 60;
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}
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break;
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case '-':
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if (!adjmin(t, '-', val / 60))
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return 0;
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val %= 60;
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if (val > t->tm_sec) {
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if (!adjmin(t, '-', 1))
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if (val) {
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if (!adjmin(t, '-', val / 60))
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return 0;
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val -= 60;
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val %= 60;
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if (val > t->tm_sec) {
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if (!adjmin(t, '-', 1))
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return 0;
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val -= 60;
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}
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t->tm_sec -= val;
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}
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t->tm_sec -= val;
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break;
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default:
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@ -368,7 +421,7 @@ adjsec(struct tm *t, char type, int val)
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t->tm_sec = val;
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}
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return mktime(t) != -1;
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return domktime(t, type) != -1;
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}
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const struct vary *
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