src/vppinfra/time_range.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2018 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <vppinfra/time_range.h>

 void
 clib_timebase_init (clib_timebase_t * tb, i32 timezone_offset_in_hours,
 		    clib_timebase_daylight_time_t daylight_type)
 {
   clib_memset (tb, 0, sizeof (*tb));

   clib_time_init (&tb->clib_time);
   tb->time_zero = unix_time_now ();

   tb->timezone_offset = ((f64) (timezone_offset_in_hours)) * 3600.0;
   tb->daylight_time_type = daylight_type;
   switch (tb->daylight_time_type)
     {
     case CLIB_TIMEBASE_DAYLIGHT_NONE:
       tb->summer_offset = 0.0;
       break;
     case CLIB_TIMEBASE_DAYLIGHT_USA:
       tb->summer_offset = 3600.0;
       break;
     default:
       clib_warning ("unknown daylight type %d", tb->daylight_time_type);
       tb->daylight_time_type = CLIB_TIMEBASE_DAYLIGHT_NONE;
       tb->summer_offset = 0.0;
     }
 }

 const static u32 days_per_month[] = {
   31,				/* Jan */
   28,				/* Feb */
   31,				/* Mar */
   30,				/* Apr */
   31,				/* May */
   30,				/* Jun */
   31,				/* Jul */
   31,				/* Aug */
   30,				/* Sep */
   31,				/* Oct */
   30,				/* Nov */
   31,				/* Dec */
 };

 const static char *month_short_names[] = {
   "Jan",
   "Feb",
   "Mar",
   "Apr",
   "May",
   "Jun",
   "Jul",
   "Aug",
   "Sep",
   "Oct",
   "Nov",
   "Dec",
 };

 const static char *day_names_epoch_order[] = {
   "Thu",
   "Fri",
   "Sat",
   "Sun",
   "Mon",
   "Tue",
   "Wed",
 };

 const static char *day_names_calendar_order[] = {
   "Sun",
   "Mon",
   "Tue",
   "Wed",
   "Thu",
   "Fri",
   "Sat",
 };


 void
 clib_timebase_time_to_components (f64 now, clib_timebase_component_t * cp)
 {
   u32 year, month, hours, minutes, seconds, nanoseconds;
   u32 days_in_year, days_in_month, day_of_month;
   u32 days_since_epoch;
   u32 day_name_index;

   /* Unix epoch is 1/1/1970 00:00:00.00, a Thursday */

   year = 1970;
   days_since_epoch = 0;

   do
     {
       days_in_year = clib_timebase_is_leap_year (year) ? 366 : 365;
       days_since_epoch += days_in_year;
       now = now - ((f64) days_in_year) * 86400.0;
       year++;
     }
   while (now > 0.0);

   days_since_epoch -= days_in_year;
   now += ((f64) days_in_year) * 86400;
   year--;

   month = 0;

   do
     {
       days_in_month = days_per_month[month];
       if (month == 1 && clib_timebase_is_leap_year (year))
 	days_in_month++;

       days_since_epoch += days_in_month;
       now = now - ((f64) days_in_month) * 86400.0;
       month++;
     }
   while (now > 0.0);

   days_since_epoch -= days_in_month;
   now += ((f64) days_in_month) * 86400;
   month--;

   day_of_month = 1;
   do
     {
       now = now - 86400;
       day_of_month++;
       days_since_epoch++;
     }
   while (now > 0.0);

   day_of_month--;
   days_since_epoch--;
   now += 86400.0;

   day_name_index = days_since_epoch % 7;

   hours = (u32) (now / (3600.0));
   now -= (f64) (hours * 3600);

   minutes = (u32) (now / 60.0);
   now -= (f64) (minutes * 60);

   seconds = (u32) (now);
   now -= (f64) (seconds);

   nanoseconds = (f64) (now * 1e9);

   cp->year = year;
   cp->month = month;
   cp->day = day_of_month;
   cp->day_name_index = day_name_index;
   cp->hour = hours;
   cp->minute = minutes;
   cp->second = seconds;
   cp->nanosecond = nanoseconds;
   cp->fractional_seconds = now;
 }

 f64
 clib_timebase_components_to_time (clib_timebase_component_t * cp)
 {
   f64 now = 0;
   u32 year, days_in_year, month, days_in_month;

   year = 1970;

   while (year < cp->year)
     {
       days_in_year = clib_timebase_is_leap_year (year) ? 366 : 365;
       now += ((f64) days_in_year) * 86400.0;
       year++;
     }

   month = 0;

   while (month < cp->month)
     {
       days_in_month = days_per_month[month];
       if (month == 1 && clib_timebase_is_leap_year (year))
 	days_in_month++;

       now += ((f64) days_in_month) * 86400.0;
       month++;
     }

   now += ((f64) cp->day - 1) * 86400.0;
   now += ((f64) cp->hour) * 3600.0;
   now += ((f64) cp->minute) * 60.0;
   now += ((f64) cp->second);
   now += ((f64) cp->nanosecond) * 1e-9;

   return (now);
 }

 f64
 clib_timebase_find_sunday_midnight (f64 start_time)
 {
   clib_timebase_component_t _c, *cp = &_c;

   clib_timebase_time_to_components (start_time, cp);

   /* back up to midnight */
   cp->hour = cp->minute = cp->second = 0;

   start_time = clib_timebase_components_to_time (cp);

   while (cp->day_name_index != 3 /* sunday */ )
     {
       /* Back up one day */
       start_time -= 86400.0;
       clib_timebase_time_to_components (start_time, cp);
     }
   /* Clean up residual fraction */
   start_time -= cp->fractional_seconds;
   start_time += 1e-6;		/* 1us inside Sunday  */

   return (start_time);
 }

 f64
 clib_timebase_offset_from_sunday (u8 * day)
 {
   int i;

   for (i = 0; i < ARRAY_LEN (day_names_calendar_order); i++)
     {
       if (!strncmp ((char *) day, day_names_calendar_order[i], 3))
 	return ((f64) i) * 86400.0;
     }
   return 0.0;
 }


 u8 *
 format_clib_timebase_time (u8 * s, va_list * args)
 {
   f64 now = va_arg (*args, f64);
   clib_timebase_component_t _c, *cp = &_c;

   clib_timebase_time_to_components (now, cp);

   s = format (s, "%s, %u %s %u %u:%02u:%02u",
 	      day_names_epoch_order[cp->day_name_index],
 	      cp->day,
 	      month_short_names[cp->month],
 	      cp->year, cp->hour, cp->minute, cp->second);
   return (s);
 }

 uword
 unformat_clib_timebase_range_hms (unformat_input_t * input, va_list * args)
 {
   clib_timebase_range_t *rp = va_arg (*args, clib_timebase_range_t *);
   clib_timebase_component_t _c, *cp = &_c;
   u32 start_hour, start_minute, start_second;
   u32 end_hour, end_minute, end_second;

   start_hour = start_minute = start_second
     = end_hour = end_minute = end_second = 0;

   if (unformat (input, "%u:%u:%u - %u:%u:%u",
 		&start_hour, &start_minute, &start_second,
 		&end_hour, &end_minute, &end_second))
     ;
   else if (unformat (input, "%u:%u - %u:%u",
 		     &start_hour, &start_minute, &end_hour, &end_minute))
     ;
   else if (unformat (input, "%u - %u", &start_hour, &end_hour))
     ;
   else
     return 0;

   clib_timebase_time_to_components (1e-6, cp);

   cp->hour = start_hour;
   cp->minute = start_minute;
   cp->second = start_second;

   rp->start = clib_timebase_components_to_time (cp);

   cp->hour = end_hour;
   cp->minute = end_minute;
   cp->second = end_second;

   rp->end = clib_timebase_components_to_time (cp);

   return 1;
 }

 uword
 unformat_clib_timebase_range_vector (unformat_input_t * input, va_list * args)
 {
   clib_timebase_range_t **rpp = va_arg (*args, clib_timebase_range_t **);
   clib_timebase_range_t _tmp, *tmp = &_tmp;
   clib_timebase_range_t *rp, *new_rp;
   int day_range_match = 0;
   int time_range_match = 0;
   f64 range_start_time_offset;
   f64 range_end_time_offset;
   f64 now;
   u8 *start_day = 0, *end_day = 0;

   rp = *rpp;

   while (1)
     {
       if (!day_range_match
 	  && unformat (input, "%s - %s", &start_day, &end_day))
 	{
 	  range_start_time_offset
 	    = clib_timebase_offset_from_sunday (start_day);
 	  range_end_time_offset = clib_timebase_offset_from_sunday (end_day);
 	  vec_free (start_day);
 	  vec_free (end_day);
 	  day_range_match = 1;
 	  time_range_match = 0;
 	}
       else if (!day_range_match && unformat (input, "%s", &start_day))
 	{
 	  range_start_time_offset
 	    = clib_timebase_offset_from_sunday (start_day);
 	  range_end_time_offset = range_start_time_offset + 86399.0;
 	  day_range_match = 1;
 	  vec_free (start_day);
 	  day_range_match = 1;
 	  time_range_match = 0;
 	}
       else if (day_range_match &&
 	       unformat (input, "%U", unformat_clib_timebase_range_hms, tmp))
 	{
 	  /* Across the week... */
 	  for (now = range_start_time_offset; now <= range_end_time_offset;
 	       now += 86400.0)
 	    {
 	      vec_add2 (rp, new_rp, 1);
 	      new_rp->start = now + tmp->start;
 	      new_rp->end = now + tmp->end;
 	    }
 	  day_range_match = 0;
 	  time_range_match = 1;
 	}
       else if (time_range_match)
 	break;
       else
 	{
 	  vec_free (rp);
 	  *rpp = 0;
 	  return 0;
 	}
     }

   if (time_range_match)
     {
       *rpp = rp;
       return 1;
     }
   else
     {
       vec_free (rp);
       *rpp = 0;
       return 0;
     }
 }

 f64
 clib_timebase_summer_offset (clib_timebase_t * tb, f64 now)
 {
   clib_timebase_component_t _c, *cp = &_c;
   f64 second_sunday_march_2am;
   f64 first_sunday_november_2am;

   if (PREDICT_TRUE
       (now >= tb->cached_year_start && now <= tb->cached_year_end))
     {
       if (now >= tb->cached_summer_start && now <= tb->cached_summer_end)
 	return tb->summer_offset;
       else
 	return (0.0);
     }

   clib_timebase_time_to_components (now, cp);

   cp->month = 0;
   cp->day = 1;
   cp->hour = 0;
   cp->minute = 0;
   cp->second = 1;

   tb->cached_year_start = clib_timebase_components_to_time (cp);

   cp->year += 1;

   tb->cached_year_end = clib_timebase_components_to_time (cp);

   cp->year -= 1;

   /* Search for the second sunday in march, 2am */
   cp->month = 2;
   cp->day = 1;
   cp->hour = 2;
   cp->second = 0;
   cp->nanosecond = 1;

   /* March 1st will never be the second sunday... */
   second_sunday_march_2am = clib_timebase_components_to_time (cp);
   cp->day_name_index = 0;

   /* Find the first sunday */
   do
     {
       clib_timebase_time_to_components (second_sunday_march_2am, cp);
       second_sunday_march_2am += 86400.0;
     }
   while (cp->day_name_index != 3 /* sunday */ );

   /* Find the second sunday */
   do
     {
       clib_timebase_time_to_components (second_sunday_march_2am, cp);
       second_sunday_march_2am += 86400.0;
     }
   while (cp->day_name_index != 3 /* sunday */ );

   second_sunday_march_2am -= 86400.0;

   tb->cached_summer_start = second_sunday_march_2am;

   /* Find the first sunday in November, which can easily be 11/1 */
   cp->month = 10;
   cp->day = 1;

   first_sunday_november_2am = clib_timebase_components_to_time (cp);
   clib_timebase_time_to_components (first_sunday_november_2am, cp);

   while (cp->day_name_index != 3 /* sunday */ )
     {
       first_sunday_november_2am += 86400.0;
       clib_timebase_time_to_components (first_sunday_november_2am, cp);
     }

   tb->cached_summer_end = first_sunday_november_2am;

   if (now >= tb->cached_summer_start && now <= tb->cached_summer_end)
     return tb->summer_offset;
   else
     return (0.0);
 }

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* Copyright (c) 2018 Cisco and/or its affiliates.
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at:
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <vppinfra/time_range.h>

	void
	clib_timebase_init (clib_timebase_t * tb, i32 timezone_offset_in_hours,
	clib_timebase_daylight_time_t daylight_type)
	{
	clib_memset (tb, 0, sizeof (*tb));

	clib_time_init (&tb->clib_time);
	tb->time_zero = unix_time_now ();

	tb->timezone_offset = ((f64) (timezone_offset_in_hours)) * 3600.0;
	tb->daylight_time_type = daylight_type;
	switch (tb->daylight_time_type)
	{
	case CLIB_TIMEBASE_DAYLIGHT_NONE:
	tb->summer_offset = 0.0;
	break;
	case CLIB_TIMEBASE_DAYLIGHT_USA:
	tb->summer_offset = 3600.0;
	break;
	default:
	clib_warning ("unknown daylight type %d", tb->daylight_time_type);
	tb->daylight_time_type = CLIB_TIMEBASE_DAYLIGHT_NONE;
	tb->summer_offset = 0.0;
	}
	}

	const static u32 days_per_month[] = {
	31, /* Jan */
	28, /* Feb */
	31, /* Mar */
	30, /* Apr */
	31, /* May */
	30, /* Jun */
	31, /* Jul */
	31, /* Aug */
	30, /* Sep */
	31, /* Oct */
	30, /* Nov */
	31, /* Dec */
	};

	const static char *month_short_names[] = {
	"Jan",
	"Feb",
	"Mar",
	"Apr",
	"May",
	"Jun",
	"Jul",
	"Aug",
	"Sep",
	"Oct",
	"Nov",
	"Dec",
	};

	const static char *day_names_epoch_order[] = {
	"Thu",
	"Fri",
	"Sat",
	"Sun",
	"Mon",
	"Tue",
	"Wed",
	};

	const static char *day_names_calendar_order[] = {
	"Sun",
	"Mon",
	"Tue",
	"Wed",
	"Thu",
	"Fri",
	"Sat",
	};


	void
	clib_timebase_time_to_components (f64 now, clib_timebase_component_t * cp)
	{
	u32 year, month, hours, minutes, seconds, nanoseconds;
	u32 days_in_year, days_in_month, day_of_month;
	u32 days_since_epoch;
	u32 day_name_index;

	/* Unix epoch is 1/1/1970 00:00:00.00, a Thursday */

	year = 1970;
	days_since_epoch = 0;

	do
	{
	days_in_year = clib_timebase_is_leap_year (year) ? 366 : 365;
	days_since_epoch += days_in_year;
	now = now - ((f64) days_in_year) * 86400.0;
	year++;
	}
	while (now > 0.0);

	days_since_epoch -= days_in_year;
	now += ((f64) days_in_year) * 86400;
	year--;

	month = 0;

	do
	{
	days_in_month = days_per_month[month];
	if (month == 1 && clib_timebase_is_leap_year (year))
	days_in_month++;

	days_since_epoch += days_in_month;
	now = now - ((f64) days_in_month) * 86400.0;
	month++;
	}
	while (now > 0.0);

	days_since_epoch -= days_in_month;
	now += ((f64) days_in_month) * 86400;
	month--;

	day_of_month = 1;
	do
	{
	now = now - 86400;
	day_of_month++;
	days_since_epoch++;
	}
	while (now > 0.0);

	day_of_month--;
	days_since_epoch--;
	now += 86400.0;

	day_name_index = days_since_epoch % 7;

	hours = (u32) (now / (3600.0));
	now -= (f64) (hours * 3600);

	minutes = (u32) (now / 60.0);
	now -= (f64) (minutes * 60);

	seconds = (u32) (now);
	now -= (f64) (seconds);

	nanoseconds = (f64) (now * 1e9);

	cp->year = year;
	cp->month = month;
	cp->day = day_of_month;
	cp->day_name_index = day_name_index;
	cp->hour = hours;
	cp->minute = minutes;
	cp->second = seconds;
	cp->nanosecond = nanoseconds;
	cp->fractional_seconds = now;
	}

	f64
	clib_timebase_components_to_time (clib_timebase_component_t * cp)
	{
	f64 now = 0;
	u32 year, days_in_year, month, days_in_month;

	year = 1970;

	while (year < cp->year)
	{
	days_in_year = clib_timebase_is_leap_year (year) ? 366 : 365;
	now += ((f64) days_in_year) * 86400.0;
	year++;
	}

	month = 0;

	while (month < cp->month)
	{
	days_in_month = days_per_month[month];
	if (month == 1 && clib_timebase_is_leap_year (year))
	days_in_month++;

	now += ((f64) days_in_month) * 86400.0;
	month++;
	}

	now += ((f64) cp->day - 1) * 86400.0;
	now += ((f64) cp->hour) * 3600.0;
	now += ((f64) cp->minute) * 60.0;
	now += ((f64) cp->second);
	now += ((f64) cp->nanosecond) * 1e-9;

	return (now);
	}

	f64
	clib_timebase_find_sunday_midnight (f64 start_time)
	{
	clib_timebase_component_t _c, *cp = &_c;

	clib_timebase_time_to_components (start_time, cp);

	/* back up to midnight */
	cp->hour = cp->minute = cp->second = 0;

	start_time = clib_timebase_components_to_time (cp);

	while (cp->day_name_index != 3 /* sunday */ )
	{
	/* Back up one day */
	start_time -= 86400.0;
	clib_timebase_time_to_components (start_time, cp);
	}
	/* Clean up residual fraction */
	start_time -= cp->fractional_seconds;
	start_time += 1e-6; /* 1us inside Sunday */

	return (start_time);
	}

	f64
	clib_timebase_offset_from_sunday (u8 * day)
	{
	int i;

	for (i = 0; i < ARRAY_LEN (day_names_calendar_order); i++)
	{
	if (!strncmp ((char *) day, day_names_calendar_order[i], 3))
	return ((f64) i) * 86400.0;
	}
	return 0.0;
	}


	u8 *
	format_clib_timebase_time (u8 * s, va_list * args)
	{
	f64 now = va_arg (*args, f64);
	clib_timebase_component_t _c, *cp = &_c;

	clib_timebase_time_to_components (now, cp);

	s = format (s, "%s, %u %s %u %u:%02u:%02u",
	day_names_epoch_order[cp->day_name_index],
	cp->day,
	month_short_names[cp->month],
	cp->year, cp->hour, cp->minute, cp->second);
	return (s);
	}

	uword
	unformat_clib_timebase_range_hms (unformat_input_t * input, va_list * args)
	{
	clib_timebase_range_t rp = va_arg (args, clib_timebase_range_t *);
	clib_timebase_component_t _c, *cp = &_c;
	u32 start_hour, start_minute, start_second;
	u32 end_hour, end_minute, end_second;

	start_hour = start_minute = start_second
	= end_hour = end_minute = end_second = 0;

	if (unformat (input, "%u:%u:%u - %u:%u:%u",
	&start_hour, &start_minute, &start_second,
	&end_hour, &end_minute, &end_second))
	;
	else if (unformat (input, "%u:%u - %u:%u",
	&start_hour, &start_minute, &end_hour, &end_minute))
	;
	else if (unformat (input, "%u - %u", &start_hour, &end_hour))
	;
	else
	return 0;

	clib_timebase_time_to_components (1e-6, cp);

	cp->hour = start_hour;
	cp->minute = start_minute;
	cp->second = start_second;

	rp->start = clib_timebase_components_to_time (cp);

	cp->hour = end_hour;
	cp->minute = end_minute;
	cp->second = end_second;

	rp->end = clib_timebase_components_to_time (cp);

	return 1;
	}

	uword
	unformat_clib_timebase_range_vector (unformat_input_t * input, va_list * args)
	{
	clib_timebase_range_t *rpp = va_arg (args, clib_timebase_range_t **);
	clib_timebase_range_t _tmp, *tmp = &_tmp;
	clib_timebase_range_t rp, new_rp;
	int day_range_match = 0;
	int time_range_match = 0;
	f64 range_start_time_offset;
	f64 range_end_time_offset;
	f64 now;
	u8 start_day = 0, end_day = 0;

	rp = *rpp;

	while (1)
	{
	if (!day_range_match
	&& unformat (input, "%s - %s", &start_day, &end_day))
	{
	range_start_time_offset
	= clib_timebase_offset_from_sunday (start_day);
	range_end_time_offset = clib_timebase_offset_from_sunday (end_day);
	vec_free (start_day);
	vec_free (end_day);
	day_range_match = 1;
	time_range_match = 0;
	}
	else if (!day_range_match && unformat (input, "%s", &start_day))
	{
	range_start_time_offset
	= clib_timebase_offset_from_sunday (start_day);
	range_end_time_offset = range_start_time_offset + 86399.0;
	day_range_match = 1;
	vec_free (start_day);
	day_range_match = 1;
	time_range_match = 0;
	}
	else if (day_range_match &&
	unformat (input, "%U", unformat_clib_timebase_range_hms, tmp))
	{
	/* Across the week... */
	for (now = range_start_time_offset; now <= range_end_time_offset;
	now += 86400.0)
	{
	vec_add2 (rp, new_rp, 1);
	new_rp->start = now + tmp->start;
	new_rp->end = now + tmp->end;
	}
	day_range_match = 0;
	time_range_match = 1;
	}
	else if (time_range_match)
	break;
	else
	{
	vec_free (rp);
	*rpp = 0;
	return 0;
	}
	}

	if (time_range_match)
	{
	*rpp = rp;
	return 1;
	}
	else
	{
	vec_free (rp);
	*rpp = 0;
	return 0;
	}
	}

	f64
	clib_timebase_summer_offset (clib_timebase_t * tb, f64 now)
	{
	clib_timebase_component_t _c, *cp = &_c;
	f64 second_sunday_march_2am;
	f64 first_sunday_november_2am;

	if (PREDICT_TRUE
	(now >= tb->cached_year_start && now <= tb->cached_year_end))
	{
	if (now >= tb->cached_summer_start && now <= tb->cached_summer_end)
	return tb->summer_offset;
	else
	return (0.0);
	}

	clib_timebase_time_to_components (now, cp);

	cp->month = 0;
	cp->day = 1;
	cp->hour = 0;
	cp->minute = 0;
	cp->second = 1;

	tb->cached_year_start = clib_timebase_components_to_time (cp);

	cp->year += 1;

	tb->cached_year_end = clib_timebase_components_to_time (cp);

	cp->year -= 1;

	/* Search for the second sunday in march, 2am */
	cp->month = 2;
	cp->day = 1;
	cp->hour = 2;
	cp->second = 0;
	cp->nanosecond = 1;

	/* March 1st will never be the second sunday... */
	second_sunday_march_2am = clib_timebase_components_to_time (cp);
	cp->day_name_index = 0;

	/* Find the first sunday */
	do
	{
	clib_timebase_time_to_components (second_sunday_march_2am, cp);
	second_sunday_march_2am += 86400.0;
	}
	while (cp->day_name_index != 3 /* sunday */ );

	/* Find the second sunday */
	do
	{
	clib_timebase_time_to_components (second_sunday_march_2am, cp);
	second_sunday_march_2am += 86400.0;
	}
	while (cp->day_name_index != 3 /* sunday */ );

	second_sunday_march_2am -= 86400.0;

	tb->cached_summer_start = second_sunday_march_2am;

	/* Find the first sunday in November, which can easily be 11/1 */
	cp->month = 10;
	cp->day = 1;

	first_sunday_november_2am = clib_timebase_components_to_time (cp);
	clib_timebase_time_to_components (first_sunday_november_2am, cp);

	while (cp->day_name_index != 3 /* sunday */ )
	{
	first_sunday_november_2am += 86400.0;
	clib_timebase_time_to_components (first_sunday_november_2am, cp);
	}

	tb->cached_summer_end = first_sunday_november_2am;

	if (now >= tb->cached_summer_start && now <= tb->cached_summer_end)
	return tb->summer_offset;
	else
	return (0.0);
	}

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/