/* Convert a 'struct tm' to a time_t value.

   Copyright (C) 1993-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Paul Eggert <eggert@twinsun.com>.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

/* Define this to have a standalone program to test this implementation of

   mktime.  */

/* #define DEBUG_MKTIME 1 */

#ifndef _LIBC

# include <config.h>

#endif

/* Assume that leap seconds are possible, unless told otherwise.

   If the host has a 'zic' command with a '-L leapsecondfilename' option,

   then it supports leap seconds; otherwise it probably doesn't.  */

#ifndef LEAP_SECONDS_POSSIBLE

# define LEAP_SECONDS_POSSIBLE 1

#endif

#include <time.h>

#include <limits.h>

#include <string.h>		/* For the real memcpy prototype.  */

#if defined DEBUG_MKTIME && DEBUG_MKTIME

# include <stdio.h>

# include <stdlib.h>

/* Make it work even if the system's libc has its own mktime routine.  */

# undef mktime

# define mktime my_mktime

#endif /* DEBUG_MKTIME */

/* Some of the code in this file assumes that signed integer overflow

   silently wraps around.  This assumption can't easily be programmed

   around, nor can it be checked for portably at compile-time or

   easily eliminated at run-time.

   Define WRAPV to 1 if the assumption is valid and if

     #pragma GCC optimize ("wrapv")

   does not trigger GCC bug 51793

   <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793>.

   Otherwise, define it to 0; this forces the use of slower code that,

   while not guaranteed by the C Standard, works on all production

   platforms that we know about.  */

#ifndef WRAPV

# if (((__GNUC__ == 4 && 4 <= __GNUC_MINOR__) || 4 < __GNUC__) \

      && defined __GLIBC__)

#  pragma GCC optimize ("wrapv")

#  define WRAPV 1

# else

#  define WRAPV 0

# endif

#endif

/* Verify a requirement at compile-time (unlike assert, which is runtime).  */

#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }

/* A signed type that is at least one bit wider than int.  */

#if INT_MAX <= LONG_MAX / 2

typedef long int long_int;

#else

typedef long long int long_int;

#endif

verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);

/* Shift A right by B bits portably, by dividing A by 2**B and

   truncating towards minus infinity.  A and B should be free of side

   effects, and B should be in the range 0 <= B <= INT_BITS - 2, where

   INT_BITS is the number of useful bits in an int.  GNU code can

   assume that INT_BITS is at least 32.

   ISO C99 says that A >> B is implementation-defined if A < 0.  Some

   implementations (e.g., UNICOS 9.0 on a Cray Y-MP EL) don't shift

   right in the usual way when A < 0, so SHR falls back on division if

   ordinary A >> B doesn't seem to be the usual signed shift.  */

#define SHR(a, b)                                               \

  ((-1 >> 1 == -1                                               \

    && (long_int) -1 >> 1 == -1                                 \

    && ((time_t) -1 >> 1 == -1 || ! TYPE_SIGNED (time_t)))      \

   ? (a) >> (b)                                                 \

   : (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))

/* The extra casts in the following macros work around compiler bugs,

   e.g., in Cray C 5.0.3.0.  */

/* True if the arithmetic type T is an integer type.  bool counts as

   an integer.  */

#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)

/* True if negative values of the signed integer type T use two's

   complement, or if T is an unsigned integer type.  */

#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)

/* True if the arithmetic type T is signed.  */

#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))

/* The maximum and minimum values for the integer type T.  These

   macros have undefined behavior if T is signed and has padding bits.

   If this is a problem for you, please let us know how to fix it for

   your host.  */

#define TYPE_MINIMUM(t) \

  ((t) (! TYPE_SIGNED (t) \

	? (t) 0 \

	: ~ TYPE_MAXIMUM (t)))

#define TYPE_MAXIMUM(t) \

  ((t) (! TYPE_SIGNED (t) \

	? (t) -1 \

	: ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))

#ifndef TIME_T_MIN

# define TIME_T_MIN TYPE_MINIMUM (time_t)

#endif

#ifndef TIME_T_MAX

# define TIME_T_MAX TYPE_MAXIMUM (time_t)

#endif

#define TIME_T_MIDPOINT (SHR (TIME_T_MIN + TIME_T_MAX, 1) + 1)

verify (time_t_is_integer, TYPE_IS_INTEGER (time_t));

verify (twos_complement_arithmetic,

	(TYPE_TWOS_COMPLEMENT (int)

	 && TYPE_TWOS_COMPLEMENT (long_int)

	 && TYPE_TWOS_COMPLEMENT (time_t)));

#define EPOCH_YEAR 1970

#define TM_YEAR_BASE 1900

verify (base_year_is_a_multiple_of_100, TM_YEAR_BASE % 100 == 0);

/* Return 1 if YEAR + TM_YEAR_BASE is a leap year.  */

static int

leapyear (long_int year)

{

  /* Don't add YEAR to TM_YEAR_BASE, as that might overflow.

     Also, work even if YEAR is negative.  */

  return

    ((year & 3) == 0

     && (year % 100 != 0

	 || ((year / 100) & 3) == (- (TM_YEAR_BASE / 100) & 3)));

}

/* How many days come before each month (0-12).  */

#ifndef _LIBC

static

#endif

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 }

  };

#ifndef _LIBC

/* Portable standalone applications should supply a <time.h> that

   declares a POSIX-compliant localtime_r, for the benefit of older

   implementations that lack localtime_r or have a nonstandard one.

   See the gnulib time_r module for one way to implement this.  */

# undef __localtime_r

# define __localtime_r localtime_r

# define __mktime_internal mktime_internal

# include "mktime-internal.h"

#endif

/* Return 1 if the values A and B differ according to the rules for

   tm_isdst: A and B differ if one is zero and the other positive.  */

static int

isdst_differ (int a, int b)

{

  return (!a != !b) && (0 <= a) && (0 <= b);

}

/* Return an integer value measuring (YEAR1-YDAY1 HOUR1:MIN1:SEC1) -

   (YEAR0-YDAY0 HOUR0:MIN0:SEC0) in seconds, assuming that the clocks

   were not adjusted between the time stamps.

   The YEAR values uses the same numbering as TP->tm_year.  Values

   need not be in the usual range.  However, YEAR1 must not be less

   than 2 * INT_MIN or greater than 2 * INT_MAX.

   The result may overflow.  It is the caller's responsibility to

   detect overflow.  */

static time_t

ydhms_diff (long_int year1, long_int yday1, int hour1, int min1, int sec1,

	    int year0, int yday0, int hour0, int min0, int sec0)

{

  verify (C99_integer_division, -1 / 2 == 0);

  /* Compute intervening leap days correctly even if year is negative.

     Take care to avoid integer overflow here.  */

  int a4 = SHR (year1, 2) + SHR (TM_YEAR_BASE, 2) - ! (year1 & 3);

  int b4 = SHR (year0, 2) + SHR (TM_YEAR_BASE, 2) - ! (year0 & 3);

  int a100 = a4 / 25 - (a4 % 25 < 0);

  int b100 = b4 / 25 - (b4 % 25 < 0);

  int a400 = SHR (a100, 2);

  int b400 = SHR (b100, 2);

  int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);

  /* Compute the desired time in time_t precision.  Overflow might

     occur here.  */

  time_t tyear1 = year1;

  time_t years = tyear1 - year0;

  time_t days = 365 * years + yday1 - yday0 + intervening_leap_days;

  time_t hours = 24 * days + hour1 - hour0;

  time_t minutes = 60 * hours + min1 - min0;

  time_t seconds = 60 * minutes + sec1 - sec0;

  return seconds;

}

/* Return the average of A and B, even if A + B would overflow.  */

static time_t

time_t_avg (time_t a, time_t b)

{

  return SHR (a, 1) + SHR (b, 1) + (a & b & 1);

}

/* Return 1 if A + B does not overflow.  If time_t is unsigned and if

   B's top bit is set, assume that the sum represents A - -B, and

   return 1 if the subtraction does not wrap around.  */

static int

time_t_add_ok (time_t a, time_t b)

{

  if (! TYPE_SIGNED (time_t))

    {

      time_t sum = a + b;

      return (sum < a) == (TIME_T_MIDPOINT <= b);

    }

  else if (WRAPV)

    {

      time_t sum = a + b;

      return (sum < a) == (b < 0);

    }

  else

    {

      time_t avg = time_t_avg (a, b);

      return TIME_T_MIN / 2 <= avg && avg <= TIME_T_MAX / 2;

    }

}

/* Return 1 if A + B does not overflow.  */

static int

time_t_int_add_ok (time_t a, int b)

{

  verify (int_no_wider_than_time_t, INT_MAX <= TIME_T_MAX);

  if (WRAPV)

    {

      time_t sum = a + b;

      return (sum < a) == (b < 0);

    }

  else

    {

      int a_odd = a & 1;

      time_t avg = SHR (a, 1) + (SHR (b, 1) + (a_odd & b));

      return TIME_T_MIN / 2 <= avg && avg <= TIME_T_MAX / 2;

    }

}

/* Return a time_t value corresponding to (YEAR-YDAY HOUR:MIN:SEC),

   assuming that *T corresponds to *TP and that no clock adjustments

   occurred between *TP and the desired time.

   If TP is null, return a value not equal to *T; this avoids false matches.

   If overflow occurs, yield the minimal or maximal value, except do not

   yield a value equal to *T.  */

static time_t

guess_time_tm (long_int year, long_int yday, int hour, int min, int sec,

	       const time_t *t, const struct tm *tp)

{

  if (tp)

    {

      time_t d = ydhms_diff (year, yday, hour, min, sec,

			     tp->tm_year, tp->tm_yday,

			     tp->tm_hour, tp->tm_min, tp->tm_sec);

      if (time_t_add_ok (*t, d))

	return *t + d;

    }

  /* Overflow occurred one way or another.  Return the nearest result

     that is actually in range, except don't report a zero difference

     if the actual difference is nonzero, as that would cause a false

     match; and don't oscillate between two values, as that would

     confuse the spring-forward gap detector.  */

  return (*t < TIME_T_MIDPOINT

	  ? (*t <= TIME_T_MIN + 1 ? *t + 1 : TIME_T_MIN)

	  : (TIME_T_MAX - 1 <= *t ? *t - 1 : TIME_T_MAX));

}

/* Use CONVERT to convert *T to a broken down time in *TP.

   If *T is out of range for conversion, adjust it so that

   it is the nearest in-range value and then convert that.  */

static struct tm *

ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),

		time_t *t, struct tm *tp)

{

  struct tm *r = convert (t, tp);

  if (!r && *t)

    {

      time_t bad = *t;

      time_t ok = 0;

      /* BAD is a known unconvertible time_t, and OK is a known good one.

	 Use binary search to narrow the range between BAD and OK until

	 they differ by 1.  */

      while (bad != ok + (bad < 0 ? -1 : 1))

	{

	  time_t mid = *t = time_t_avg (ok, bad);

	  r = convert (t, tp);

	  if (r)

	    ok = mid;

	  else

	    bad = mid;

	}

      if (!r && ok)

	{

	  /* The last conversion attempt failed;

	     revert to the most recent successful attempt.  */

	  *t = ok;

	  r = convert (t, tp);

	}

    }

  return r;

}

/* Convert *TP to a time_t value, inverting

   the monotonic and mostly-unit-linear conversion function CONVERT.

   Use *OFFSET to keep track of a guess at the offset of the result,

   compared to what the result would be for UTC without leap seconds.

   If *OFFSET's guess is correct, only one CONVERT call is needed.

   This function is external because it is used also by timegm.c.  */

time_t

__mktime_internal (struct tm *tp,

		   struct tm *(*convert) (const time_t *, struct tm *),

		   time_t *offset)

{

  time_t t, gt, t0, t1, t2;

  struct tm tm;

  /* The maximum number of probes (calls to CONVERT) should be enough

     to handle any combinations of time zone rule changes, solar time,

     leap seconds, and oscillations around a spring-forward gap.

     POSIX.1 prohibits leap seconds, but some hosts have them anyway.  */

  int remaining_probes = 6;

  /* Time requested.  Copy it in case CONVERT modifies *TP; this can

     occur if TP is localtime's returned value and CONVERT is localtime.  */

  int sec = tp->tm_sec;

  int min = tp->tm_min;

  int hour = tp->tm_hour;

  int mday = tp->tm_mday;

  int mon = tp->tm_mon;

  int year_requested = tp->tm_year;

  int isdst = tp->tm_isdst;

  /* 1 if the previous probe was DST.  */

  int dst2;

  /* Ensure that mon is in range, and set year accordingly.  */

  int mon_remainder = mon % 12;

  int negative_mon_remainder = mon_remainder < 0;

  int mon_years = mon / 12 - negative_mon_remainder;

  long_int lyear_requested = year_requested;

  long_int year = lyear_requested + mon_years;

  /* The other values need not be in range:

     the remaining code handles minor overflows correctly,

     assuming int and time_t arithmetic wraps around.

     Major overflows are caught at the end.  */

  /* Calculate day of year from year, month, and day of month.

     The result need not be in range.  */

  int mon_yday = ((__mon_yday[leapyear (year)]

		   [mon_remainder + 12 * negative_mon_remainder])

		  - 1);

  long_int lmday = mday;

  long_int yday = mon_yday + lmday;

  time_t guessed_offset = *offset;

  int sec_requested = sec;

  if (LEAP_SECONDS_POSSIBLE)

    {

      /* Handle out-of-range seconds specially,

	 since ydhms_tm_diff assumes every minute has 60 seconds.  */

      if (sec < 0)

	sec = 0;

      if (59 < sec)

	sec = 59;

    }

  /* Invert CONVERT by probing.  First assume the same offset as last

     time.  */

  t0 = ydhms_diff (year, yday, hour, min, sec,

		   EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, - guessed_offset);

  if (TIME_T_MAX / INT_MAX / 366 / 24 / 60 / 60 < 3)

    {

      /* time_t isn't large enough to rule out overflows, so check

	 for major overflows.  A gross check suffices, since if t0

	 has overflowed, it is off by a multiple of TIME_T_MAX -

	 TIME_T_MIN + 1.  So ignore any component of the difference

	 that is bounded by a small value.  */

      /* Approximate log base 2 of the number of time units per

	 biennium.  A biennium is 2 years; use this unit instead of

	 years to avoid integer overflow.  For example, 2 average

	 Gregorian years are 2 * 365.2425 * 24 * 60 * 60 seconds,

	 which is 63113904 seconds, and rint (log2 (63113904)) is

	 26.  */

      int ALOG2_SECONDS_PER_BIENNIUM = 26;

      int ALOG2_MINUTES_PER_BIENNIUM = 20;

      int ALOG2_HOURS_PER_BIENNIUM = 14;

      int ALOG2_DAYS_PER_BIENNIUM = 10;

      int LOG2_YEARS_PER_BIENNIUM = 1;

      int approx_requested_biennia =

	(SHR (year_requested, LOG2_YEARS_PER_BIENNIUM)

	 - SHR (EPOCH_YEAR - TM_YEAR_BASE, LOG2_YEARS_PER_BIENNIUM)

	 + SHR (mday, ALOG2_DAYS_PER_BIENNIUM)

	 + SHR (hour, ALOG2_HOURS_PER_BIENNIUM)

	 + SHR (min, ALOG2_MINUTES_PER_BIENNIUM)

	 + (LEAP_SECONDS_POSSIBLE

	    ? 0

	    : SHR (sec, ALOG2_SECONDS_PER_BIENNIUM)));

      int approx_biennia = SHR (t0, ALOG2_SECONDS_PER_BIENNIUM);

      int diff = approx_biennia - approx_requested_biennia;

      int approx_abs_diff = diff < 0 ? -1 - diff : diff;

      /* IRIX 4.0.5 cc miscalculates TIME_T_MIN / 3: it erroneously

	 gives a positive value of 715827882.  Setting a variable

	 first then doing math on it seems to work.

	 (ghazi@caip.rutgers.edu) */

      time_t time_t_max = TIME_T_MAX;

      time_t time_t_min = TIME_T_MIN;

      time_t overflow_threshold =

	(time_t_max / 3 - time_t_min / 3) >> ALOG2_SECONDS_PER_BIENNIUM;

      if (overflow_threshold < approx_abs_diff)

	{

	  /* Overflow occurred.  Try repairing it; this might work if

	     the time zone offset is enough to undo the overflow.  */

	  time_t repaired_t0 = -1 - t0;

	  approx_biennia = SHR (repaired_t0, ALOG2_SECONDS_PER_BIENNIUM);

	  diff = approx_biennia - approx_requested_biennia;

	  approx_abs_diff = diff < 0 ? -1 - diff : diff;

	  if (overflow_threshold < approx_abs_diff)

	    return -1;

	  guessed_offset += repaired_t0 - t0;

	  t0 = repaired_t0;

	}

    }

  /* Repeatedly use the error to improve the guess.  */

  for (t = t1 = t2 = t0, dst2 = 0;

       (gt = guess_time_tm (year, yday, hour, min, sec, &t,

			    ranged_convert (convert, &t, &tm)),

	t != gt);

       t1 = t2, t2 = t, t = gt, dst2 = tm.tm_isdst != 0)

    if (t == t1 && t != t2

	&& (tm.tm_isdst < 0

	    || (isdst < 0

		? dst2 <= (tm.tm_isdst != 0)

		: (isdst != 0) != (tm.tm_isdst != 0))))

      /* We can't possibly find a match, as we are oscillating

	 between two values.  The requested time probably falls

	 within a spring-forward gap of size GT - T.  Follow the common

	 practice in this case, which is to return a time that is GT - T

	 away from the requested time, preferring a time whose

	 tm_isdst differs from the requested value.  (If no tm_isdst

	 was requested and only one of the two values has a nonzero

	 tm_isdst, prefer that value.)  In practice, this is more

	 useful than returning -1.  */

      goto offset_found;

    else if (--remaining_probes == 0)

      return -1;

  /* We have a match.  Check whether tm.tm_isdst has the requested

     value, if any.  */

  if (isdst_differ (isdst, tm.tm_isdst))

    {

      /* tm.tm_isdst has the wrong value.  Look for a neighboring

	 time with the right value, and use its UTC offset.

	 Heuristic: probe the adjacent timestamps in both directions,

	 looking for the desired isdst.  This should work for all real

	 time zone histories in the tz database.  */

      /* Distance between probes when looking for a DST boundary.  In

	 tzdata2003a, the shortest period of DST is 601200 seconds

	 (e.g., America/Recife starting 2000-10-08 01:00), and the

	 shortest period of non-DST surrounded by DST is 694800

	 seconds (Africa/Tunis starting 1943-04-17 01:00).  Use the

	 minimum of these two values, so we don't miss these short

	 periods when probing.  */

      int stride = 601200;

      /* The longest period of DST in tzdata2003a is 536454000 seconds

	 (e.g., America/Jujuy starting 1946-10-01 01:00).  The longest

	 period of non-DST is much longer, but it makes no real sense

	 to search for more than a year of non-DST, so use the DST

	 max.  */

      int duration_max = 536454000;

      /* Search in both directions, so the maximum distance is half

	 the duration; add the stride to avoid off-by-1 problems.  */

      int delta_bound = duration_max / 2 + stride;

      int delta, direction;

      for (delta = stride; delta < delta_bound; delta += stride)

	for (direction = -1; direction <= 1; direction += 2)

	  if (time_t_int_add_ok (t, delta * direction))

	    {

	      time_t ot = t + delta * direction;

	      struct tm otm;

	      ranged_convert (convert, &ot, &otm;;

	      if (! isdst_differ (isdst, otm.tm_isdst))

		{

		  /* We found the desired tm_isdst.

		     Extrapolate back to the desired time.  */

		  t = guess_time_tm (year, yday, hour, min, sec, &ot, &otm;;

		  ranged_convert (convert, &t, &tm;;

		  goto offset_found;

		}

	    }

    }

 offset_found:

  *offset = guessed_offset + t - t0;

  if (LEAP_SECONDS_POSSIBLE && sec_requested != tm.tm_sec)

    {

      /* Adjust time to reflect the tm_sec requested, not the normalized value.

	 Also, repair any damage from a false match due to a leap second.  */

      int sec_adjustment = (sec == 0 && tm.tm_sec == 60) - sec;

      if (! time_t_int_add_ok (t, sec_requested))

	return -1;

      t1 = t + sec_requested;

      if (! time_t_int_add_ok (t1, sec_adjustment))

	return -1;

      t2 = t1 + sec_adjustment;

      if (! convert (&t2, &tm))

	return -1;

      t = t2;

    }

  *tp = tm;

  return t;

}

/* FIXME: This should use a signed type wide enough to hold any UTC

   offset in seconds.  'int' should be good enough for GNU code.  We

   can't fix this unilaterally though, as other modules invoke

   __mktime_internal.  */

static time_t localtime_offset;

/* Convert *TP to a time_t value.  */

time_t

mktime (struct tm *tp)

{

#ifdef _LIBC

  /* POSIX.1 8.1.1 requires that whenever mktime() is called, the

     time zone names contained in the external variable 'tzname' shall

     be set as if the tzset() function had been called.  */

  __tzset ();

#endif

  return __mktime_internal (tp, __localtime_r, &localtime_offset);

}

#ifdef weak_alias

weak_alias (mktime, timelocal)

#endif

#ifdef _LIBC

libc_hidden_def (mktime)

libc_hidden_weak (timelocal)

#endif

#if defined DEBUG_MKTIME && DEBUG_MKTIME

static int

not_equal_tm (const struct tm *a, const struct tm *b)

{

  return ((a->tm_sec ^ b->tm_sec)

	  | (a->tm_min ^ b->tm_min)

	  | (a->tm_hour ^ b->tm_hour)

	  | (a->tm_mday ^ b->tm_mday)

	  | (a->tm_mon ^ b->tm_mon)

	  | (a->tm_year ^ b->tm_year)

	  | (a->tm_yday ^ b->tm_yday)

	  | isdst_differ (a->tm_isdst, b->tm_isdst));

}

static void

print_tm (const struct tm *tp)

{

  if (tp)

    printf ("%04d-%02d-%02d %02d:%02d:%02d yday %03d wday %d isdst %d",

	    tp->tm_year + TM_YEAR_BASE, tp->tm_mon + 1, tp->tm_mday,

	    tp->tm_hour, tp->tm_min, tp->tm_sec,

	    tp->tm_yday, tp->tm_wday, tp->tm_isdst);

  else

    printf ("0");

}

static int

check_result (time_t tk, struct tm tmk, time_t tl, const struct tm *lt)

{

  if (tk != tl || !lt || not_equal_tm (&tmk, lt))

    {

      printf ("mktime (");

      print_tm (lt);

      printf (")\nyields (");

      print_tm (&tmk);

      printf (") == %ld, should be %ld\n", (long int) tk, (long int) tl);

      return 1;

    }

  return 0;

}

int

main (int argc, char **argv)

{

  int status = 0;

  struct tm tm, tmk, tml;

  struct tm *lt;

  time_t tk, tl, tl1;

  char trailer;

  if ((argc == 3 || argc == 4)

      && (sscanf (argv[1], "%d-%d-%d%c",

		  &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &trailer)

	  == 3)

      && (sscanf (argv[2], "%d:%d:%d%c",

		  &tm.tm_hour, &tm.tm_min, &tm.tm_sec, &trailer)

	  == 3))

    {

      tm.tm_year -= TM_YEAR_BASE;

      tm.tm_mon--;

      tm.tm_isdst = argc == 3 ? -1 : atoi (argv[3]);

      tmk = tm;

      tl = mktime (&tmk);

      lt = localtime (&tl;;

      if (lt)

	{

	  tml = *lt;

	  lt = &tm;;

	}

      printf ("mktime returns %ld == ", (long int) tl);

      print_tm (&tmk);

      printf ("\n");

      status = check_result (tl, tmk, tl, lt);

    }

  else if (argc == 4 || (argc == 5 && strcmp (argv[4], "-") == 0))

    {

      time_t from = atol (argv[1]);

      time_t by = atol (argv[2]);

      time_t to = atol (argv[3]);

      if (argc == 4)

	for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)

	  {

	    lt = localtime (&tl;;

	    if (lt)

	      {

		tmk = tml = *lt;

		tk = mktime (&tmk);

		status |= check_result (tk, tmk, tl, &tml);

	      }

	    else

	      {

		printf ("localtime (%ld) yields 0\n", (long int) tl);

		status = 1;

	      }

	    tl1 = tl + by;

	    if ((tl1 < tl) != (by < 0))

	      break;

	  }

      else

	for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)

	  {

	    /* Null benchmark.  */

	    lt = localtime (&tl;;

	    if (lt)

	      {

		tmk = tml = *lt;

		tk = tl;

		status |= check_result (tk, tmk, tl, &tml);

	      }

	    else

	      {

		printf ("localtime (%ld) yields 0\n", (long int) tl);

		status = 1;

	      }

	    tl1 = tl + by;

	    if ((tl1 < tl) != (by < 0))

	      break;

	  }

    }

  else

    printf ("Usage:\

\t%s YYYY-MM-DD HH:MM:SS [ISDST] # Test given time.\n\

\t%s FROM BY TO # Test values FROM, FROM+BY, ..., TO.\n\

\t%s FROM BY TO - # Do not test those values (for benchmark).\n",

	    argv[0], argv[0], argv[0]);

  return status;

}

#endif /* DEBUG_MKTIME */

/*

Local Variables:

compile-command: "gcc -DDEBUG_MKTIME -I. -Wall -W -O2 -g mktime.c -o mktime"

End:

*/