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+/**
+ * Copyright (c) 2020, Timothy Stack
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * * Neither the name of Timothy Stack nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @file time_util.cc
+ */
+
+#include <chrono>
+
+#include "time_util.hh"
+
+#include "config.h"
+
+namespace lnav {
+
+ssize_t
+strftime_rfc3339(
+ char* buffer, size_t buffer_size, lnav::time64_t tim, int millis, char sep)
+{
+ struct tm gmtm;
+ int year, month, index = 0;
+
+ secs2tm(tim, &gmtm);
+ year = gmtm.tm_year + 1900;
+ month = gmtm.tm_mon + 1;
+ buffer[index++] = '0' + ((year / 1000) % 10);
+ buffer[index++] = '0' + ((year / 100) % 10);
+ buffer[index++] = '0' + ((year / 10) % 10);
+ buffer[index++] = '0' + ((year / 1) % 10);
+ buffer[index++] = '-';
+ buffer[index++] = '0' + ((month / 10) % 10);
+ buffer[index++] = '0' + ((month / 1) % 10);
+ buffer[index++] = '-';
+ buffer[index++] = '0' + ((gmtm.tm_mday / 10) % 10);
+ buffer[index++] = '0' + ((gmtm.tm_mday / 1) % 10);
+ buffer[index++] = sep;
+ buffer[index++] = '0' + ((gmtm.tm_hour / 10) % 10);
+ buffer[index++] = '0' + ((gmtm.tm_hour / 1) % 10);
+ buffer[index++] = ':';
+ buffer[index++] = '0' + ((gmtm.tm_min / 10) % 10);
+ buffer[index++] = '0' + ((gmtm.tm_min / 1) % 10);
+ buffer[index++] = ':';
+ buffer[index++] = '0' + ((gmtm.tm_sec / 10) % 10);
+ buffer[index++] = '0' + ((gmtm.tm_sec / 1) % 10);
+ buffer[index++] = '.';
+ buffer[index++] = '0' + ((millis / 100) % 10);
+ buffer[index++] = '0' + ((millis / 10) % 10);
+ buffer[index++] = '0' + ((millis / 1) % 10);
+ buffer[index] = '\0';
+
+ return index;
+}
+
+}
+
+static time_t BAD_DATE = -1;
+
+time_t
+tm2sec(const struct tm* t)
+{
+ int year;
+ time_t days, secs;
+ const int dayoffset[12]
+ = {306, 337, 0, 31, 61, 92, 122, 153, 184, 214, 245, 275};
+
+ year = t->tm_year;
+
+ if (year < 70) {
+ return BAD_DATE;
+ }
+ if ((sizeof(time_t) <= 4) && (year >= 138)) {
+ year = 137;
+ }
+
+ /* shift new year to 1st March in order to make leap year calc easy */
+
+ if (t->tm_mon < 2) {
+ year--;
+ }
+
+ /* Find number of days since 1st March 1900 (in the Gregorian calendar). */
+
+ days = year * 365 + year / 4 - year / 100 + (year / 100 + 3) / 4;
+ days += dayoffset[t->tm_mon] + t->tm_mday - 1;
+ days -= 25508; /* 1 jan 1970 is 25508 days since 1 mar 1900 */
+
+ secs = ((days * 24 + t->tm_hour) * 60 + t->tm_min) * 60 + t->tm_sec;
+
+ if (secs < 0) {
+ return BAD_DATE;
+ } /* must have overflowed */
+ else
+ {
+#ifdef HAVE_STRUCT_TM_TM_ZONE
+ if (t->tm_zone) {
+ secs -= t->tm_gmtoff;
+ }
+#endif
+ return secs;
+ } /* must be a valid time */
+}
+
+static const int SECSPERMIN = 60;
+static const int SECSPERHOUR = 60 * SECSPERMIN;
+static const int SECSPERDAY = 24 * SECSPERHOUR;
+static const int YEAR_BASE = 1900;
+static const int EPOCH_WDAY = 4;
+static const int DAYSPERWEEK = 7;
+static const int EPOCH_YEAR = 1970;
+
+#define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
+
+static const int year_lengths[2] = {365, 366};
+
+const unsigned short int mon_yday[2][13] = {
+ /* Normal years. */
+ {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
+ /* Leap years. */
+ {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}};
+
+void
+secs2wday(const struct timeval& tv, struct tm* res)
+{
+ long days, rem;
+ time_t lcltime;
+
+ /* base decision about std/dst time on current time */
+ lcltime = tv.tv_sec;
+
+ days = ((long) lcltime) / SECSPERDAY;
+ rem = ((long) lcltime) % SECSPERDAY;
+ while (rem < 0) {
+ rem += SECSPERDAY;
+ --days;
+ }
+
+ /* compute day of week */
+ if ((res->tm_wday = ((EPOCH_WDAY + days) % DAYSPERWEEK)) < 0) {
+ res->tm_wday += DAYSPERWEEK;
+ }
+}
+
+struct tm*
+secs2tm(lnav::time64_t tim, struct tm* res)
+{
+ long days, rem;
+ lnav::time64_t lcltime;
+ int y;
+ int yleap;
+ const unsigned short int* ip;
+
+ /* base decision about std/dst time on current time */
+ lcltime = tim;
+
+ days = ((long) lcltime) / SECSPERDAY;
+ rem = ((long) lcltime) % SECSPERDAY;
+ while (rem < 0) {
+ rem += SECSPERDAY;
+ --days;
+ }
+
+ /* compute hour, min, and sec */
+ res->tm_hour = (int) (rem / SECSPERHOUR);
+ rem %= SECSPERHOUR;
+ res->tm_min = (int) (rem / SECSPERMIN);
+ res->tm_sec = (int) (rem % SECSPERMIN);
+
+ /* compute day of week */
+ if ((res->tm_wday = ((EPOCH_WDAY + days) % DAYSPERWEEK)) < 0)
+ res->tm_wday += DAYSPERWEEK;
+
+ /* compute year & day of year */
+ y = EPOCH_YEAR;
+ if (days >= 0) {
+ for (;;) {
+ yleap = isleap(y);
+ if (days < year_lengths[yleap])
+ break;
+ y++;
+ days -= year_lengths[yleap];
+ }
+ } else {
+ do {
+ --y;
+ yleap = isleap(y);
+ days += year_lengths[yleap];
+ } while (days < 0);
+ }
+
+ res->tm_year = y - YEAR_BASE;
+ res->tm_yday = days;
+ ip = mon_yday[isleap(y)];
+ for (y = 11; days < (long int) ip[y]; --y)
+ continue;
+ days -= ip[y];
+ res->tm_mon = y;
+ res->tm_mday = days + 1;
+
+ res->tm_isdst = 0;
+
+ return (res);
+}
+
+struct timeval
+exttm::to_timeval() const
+{
+ struct timeval retval;
+
+ retval.tv_sec = tm2sec(&this->et_tm);
+ retval.tv_usec = std::chrono::duration_cast<std::chrono::microseconds>(
+ std::chrono::nanoseconds(this->et_nsec))
+ .count();
+
+ return retval;
+}
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