-/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
+/* Convert a 'struct tm' to a time_t value.
+ Copyright (C) 1993-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
- Contributed by Paul Eggert (eggert@twinsun.com).
+ 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 Library General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version.
+ 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
- Library General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU Library General Public
- License along with the GNU C Library; see the file COPYING.LIB. If not,
- write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
-/* Define this to have a standalone program to test this implementation of
- mktime. */
-/* #define DEBUG 1 */
+/* The following macros influence what gets defined when this file is compiled:
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
+ Macro/expression Which gnulib module This compilation unit
+ should define
-#ifdef _LIBC
-# define HAVE_LIMITS_H 1
-# define HAVE_LOCALTIME_R 1
-# define STDC_HEADERS 1
+ _LIBC (glibc proper) mktime
+
+ NEED_MKTIME_WORKING mktime rpl_mktime
+ || NEED_MKTIME_WINDOWS
+
+ NEED_MKTIME_INTERNAL mktime-internal mktime_internal
+ */
+
+#ifndef _LIBC
+# include <libc-config.h>
#endif
/* Assume that leap seconds are possible, unless told otherwise.
- If the host has a `zic' command with a `-L leapsecondfilename' option,
+ 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
+# define LEAP_SECONDS_POSSIBLE 1
#endif
-#include <sys/types.h> /* Some systems define `time_t' here. */
#include <time.h>
-#if HAVE_LIMITS_H
+#include <errno.h>
#include <limits.h>
-#endif
-
-#if DEBUG
-#include <stdio.h>
-#if STDC_HEADERS
+#include <stdbool.h>
#include <stdlib.h>
-#endif
-/* Make it work even if the system's libc has its own mktime routine. */
-#define mktime my_mktime
-#endif /* DEBUG */
+#include <string.h>
-#ifndef __P
-#if defined (__GNUC__) || (defined (__STDC__) && __STDC__)
-#define __P(args) args
-#else
-#define __P(args) ()
-#endif /* GCC. */
-#endif /* Not __P. */
+#include <intprops.h>
+#include <verify.h>
-#ifndef CHAR_BIT
-#define CHAR_BIT 8
+#ifndef NEED_MKTIME_INTERNAL
+# define NEED_MKTIME_INTERNAL 0
#endif
-
-#ifndef INT_MIN
-#define INT_MIN (~0 << (sizeof (int) * CHAR_BIT - 1))
+#ifndef NEED_MKTIME_WINDOWS
+# define NEED_MKTIME_WINDOWS 0
#endif
-#ifndef INT_MAX
-#define INT_MAX (~0 - INT_MIN)
+#ifndef NEED_MKTIME_WORKING
+# define NEED_MKTIME_WORKING 0
#endif
-#ifndef TIME_T_MIN
-#define TIME_T_MIN (0 < (time_t) -1 ? (time_t) 0 \
- : ~ (time_t) 0 << (sizeof (time_t) * CHAR_BIT - 1))
+#include "mktime-internal.h"
+
+#if !defined _LIBC && (NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS)
+static void
+my_tzset (void)
+{
+# if NEED_MKTIME_WINDOWS
+ /* Rectify the value of the environment variable TZ.
+ There are four possible kinds of such values:
+ - Traditional US time zone names, e.g. "PST8PDT". Syntax: see
+ <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/tzset>
+ - Time zone names based on geography, that contain one or more
+ slashes, e.g. "Europe/Moscow".
+ - Time zone names based on geography, without slashes, e.g.
+ "Singapore".
+ - Time zone names that contain explicit DST rules. Syntax: see
+ <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03>
+ The Microsoft CRT understands only the first kind. It produces incorrect
+ results if the value of TZ is of the other kinds.
+ But in a Cygwin environment, /etc/profile.d/tzset.sh sets TZ to a value
+ of the second kind for most geographies, or of the first kind in a few
+ other geographies. If it is of the second kind, neutralize it. For the
+ Microsoft CRT, an absent or empty TZ means the time zone that the user
+ has set in the Windows Control Panel.
+ If the value of TZ is of the third or fourth kind -- Cygwin programs
+ understand these syntaxes as well --, it does not matter whether we
+ neutralize it or not, since these values occur only when a Cygwin user
+ has set TZ explicitly; this case is 1. rare and 2. under the user's
+ responsibility. */
+ const char *tz = getenv ("TZ");
+ if (tz != NULL && strchr (tz, '/') != NULL)
+ _putenv ("TZ=");
+# elif HAVE_TZSET
+ tzset ();
+# endif
+}
+# undef __tzset
+# define __tzset() my_tzset ()
#endif
-#ifndef TIME_T_MAX
-#define TIME_T_MAX (~ (time_t) 0 - TIME_T_MIN)
+
+#if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL
+
+/* A signed type that can represent an integer number of years
+ multiplied by four times the number of seconds in a year. It is
+ needed when converting a tm_year value times the number of seconds
+ in a year. The factor of four comes because these products need
+ to be subtracted from each other, and sometimes with an offset
+ added to them, and then with another timestamp added, without
+ worrying about overflow.
+
+ Much of the code uses long_int to represent time_t values, to
+ lessen the hassle of dealing with platforms where time_t is
+ unsigned, and because long_int should suffice to represent all
+ time_t values that mktime can generate even on platforms where
+ time_t is excessively wide. */
+
+#if INT_MAX <= LONG_MAX / 4 / 366 / 24 / 60 / 60
+typedef long int long_int;
+#else
+typedef long long int long_int;
#endif
+verify (INT_MAX <= TYPE_MAXIMUM (long_int) / 4 / 366 / 24 / 60 / 60);
+
+/* Shift A right by B bits portably, by dividing A by 2**B and
+ truncating towards minus infinity. B should be in the range 0 <= B
+ <= LONG_INT_BITS - 2, where LONG_INT_BITS is the number of useful
+ bits in a long_int. LONG_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. */
+
+static long_int
+shr (long_int a, int b)
+{
+ long_int one = 1;
+ return (-one >> 1 == -1
+ ? a >> b
+ : a / (one << b) - (a % (one << b) < 0));
+}
+
+/* Bounds for the intersection of time_t and long_int. */
+
+static long_int const mktime_min
+ = ((TYPE_SIGNED (time_t) && TYPE_MINIMUM (time_t) < TYPE_MINIMUM (long_int))
+ ? TYPE_MINIMUM (long_int) : TYPE_MINIMUM (time_t));
+static long_int const mktime_max
+ = (TYPE_MAXIMUM (long_int) < TYPE_MAXIMUM (time_t)
+ ? TYPE_MAXIMUM (long_int) : TYPE_MAXIMUM (time_t));
+
+verify (TYPE_IS_INTEGER (time_t));
-#define TM_YEAR_BASE 1900
#define EPOCH_YEAR 1970
+#define TM_YEAR_BASE 1900
+verify (TM_YEAR_BASE % 100 == 0);
-#ifndef __isleap
-/* Nonzero if YEAR is a leap year (every 4 years,
- except every 100th isn't, and every 400th is). */
-#define __isleap(year) \
- ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
-#endif
+/* Is YEAR + TM_YEAR_BASE a leap year? */
+static bool
+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, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
};
-static time_t ydhms_tm_diff __P ((int, int, int, int, int, const struct tm *));
-time_t __mktime_internal __P ((struct tm *,
- struct tm *(*) (const time_t *, struct tm *),
- time_t *));
-
-#ifdef _LIBC
-#define localtime_r __localtime_r
-#else
-#if ! HAVE_LOCALTIME_R && ! defined (localtime_r)
-/* Approximate localtime_r as best we can in its absence. */
-#define localtime_r my_localtime_r
-static struct tm *localtime_r __P ((const time_t *, struct tm *));
-static struct tm *
-localtime_r (t, tp)
- const time_t *t;
- struct tm *tp;
+/* Do 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 bool
+isdst_differ (int a, int b)
{
- struct tm *l = localtime (t);
- if (! l)
- return 0;
- *tp = *l;
- return tp;
+ return (!a != !b) && (0 <= a) && (0 <= b);
}
-#endif /* ! HAVE_LOCALTIME_R && ! defined (localtime_r) */
-#endif /* ! _LIBC */
-
-
-/* Yield the difference between (YEAR-YDAY HOUR:MIN:SEC) and (*TP),
- measured in seconds, ignoring leap seconds.
- YEAR uses the same numbering as TM->tm_year.
- All values are in range, except possibly YEAR.
- If overflow occurs, yield the low order bits of the correct answer. */
-static time_t
-ydhms_tm_diff (year, yday, hour, min, sec, tp)
- int year, yday, hour, min, sec;
- const struct tm *tp;
+
+/* 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 timestamps.
+
+ The YEAR values uses the same numbering as TP->tm_year. Values
+ need not be in the usual range. However, YEAR1 - YEAR0 must not
+ overflow even when multiplied by three times the number of seconds
+ in a year, and likewise for YDAY1 - YDAY0 and three times the
+ number of seconds in a day. */
+
+static long_int
+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 (-1 / 2 == 0);
+
/* Compute intervening leap days correctly even if year is negative.
- Take care to avoid int overflow. time_t overflow is OK, since
- only the low order bits of the correct time_t answer are needed.
- Don't convert to time_t until after all divisions are done, since
- time_t might be unsigned. */
- int a4 = (year >> 2) + (TM_YEAR_BASE >> 2) - ! (year & 3);
- int b4 = (tp->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (tp->tm_year & 3);
+ 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 = a100 >> 2;
- int b400 = b100 >> 2;
+ int a400 = shr (a100, 2);
+ int b400 = shr (b100, 2);
int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
- time_t years = year - (time_t) tp->tm_year;
- time_t days = (365 * years + intervening_leap_days
- + (yday - tp->tm_yday));
- return (60 * (60 * (24 * days + (hour - tp->tm_hour))
- + (min - tp->tm_min))
- + (sec - tp->tm_sec));
+
+ /* Compute the desired time without overflowing. */
+ long_int years = year1 - year0;
+ long_int days = 365 * years + yday1 - yday0 + intervening_leap_days;
+ long_int hours = 24 * days + hour1 - hour0;
+ long_int minutes = 60 * hours + min1 - min0;
+ long_int seconds = 60 * minutes + sec1 - sec0;
+ return seconds;
}
+/* Return the average of A and B, even if A + B would overflow.
+ Round toward positive infinity. */
+static long_int
+long_int_avg (long_int a, long_int b)
+{
+ return shr (a, 1) + shr (b, 1) + ((a | b) & 1);
+}
-static time_t localtime_offset;
+/* Return a long_int value corresponding to (YEAR-YDAY HOUR:MIN:SEC)
+ minus *TP seconds, assuming no clock adjustments occurred between
+ the two timestamps.
-/* Convert *TP to a time_t value. */
-time_t
-mktime (tp)
- struct tm *tp;
+ YEAR and YDAY must not be so large that multiplying them by three times the
+ number of seconds in a year (or day, respectively) would overflow long_int.
+ *TP should be in the usual range. */
+static long_int
+tm_diff (long_int year, long_int yday, int hour, int min, int sec,
+ struct tm const *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 ydhms_diff (year, yday, hour, min, sec,
+ tp->tm_year, tp->tm_yday,
+ tp->tm_hour, tp->tm_min, tp->tm_sec);
+}
+
+/* Use CONVERT to convert T to a struct tm value in *TM. T must be in
+ range for time_t. Return TM if successful, NULL (setting errno) on
+ failure. */
+static struct tm *
+convert_time (struct tm *(*convert) (const time_t *, struct tm *),
+ long_int t, struct tm *tm)
+{
+ time_t x = t;
+ return convert (&x, tm);
+}
+
+/* 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.
+ A value is in range if it fits in both time_t and long_int.
+ Return TP on success, NULL (setting errno) on failure. */
+static struct tm *
+ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
+ long_int *t, struct tm *tp)
+{
+ long_int t1 = (*t < mktime_min ? mktime_min
+ : *t <= mktime_max ? *t : mktime_max);
+ struct tm *r = convert_time (convert, t1, tp);
+ if (r)
+ {
+ *t = t1;
+ return r;
+ }
+ if (errno != EOVERFLOW)
+ return NULL;
+
+ long_int bad = t1;
+ long_int ok = 0;
+ struct tm oktm; oktm.tm_sec = -1;
- return __mktime_internal (tp, localtime_r, &localtime_offset);
+ /* BAD is a known out-of-range value, and OK is a known in-range one.
+ Use binary search to narrow the range between BAD and OK until
+ they differ by 1. */
+ while (true)
+ {
+ long_int mid = long_int_avg (ok, bad);
+ if (mid == ok || mid == bad)
+ break;
+ if (convert_time (convert, mid, tp))
+ ok = mid, oktm = *tp;
+ else if (errno != EOVERFLOW)
+ return NULL;
+ else
+ bad = mid;
+ }
+
+ if (oktm.tm_sec < 0)
+ return NULL;
+ *t = ok;
+ *tp = oktm;
+ return tp;
}
+
/* 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. */
+ If *OFFSET's guess is correct, only one CONVERT call is needed.
+ If successful, set *TP to the canonicalized struct tm;
+ otherwise leave *TP alone, return ((time_t) -1) and set errno.
+ This function is external because it is used also by timegm.c. */
time_t
-__mktime_internal (tp, convert, offset)
- struct tm *tp;
- struct tm *(*convert) __P ((const time_t *, struct tm *));
- time_t *offset;
+__mktime_internal (struct tm *tp,
+ struct tm *(*convert) (const time_t *, struct tm *),
+ mktime_offset_t *offset)
{
- time_t t, dt, t0;
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,
- and leap seconds. Posix.1 prohibits leap seconds, but some hosts
- have them anyway. */
- int remaining_probes = 4;
+ 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 year_requested = tp->tm_year;
int isdst = tp->tm_isdst;
+ /* 1 if the previous probe was DST. */
+ int dst2 = 0;
+
/* 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;
- int year = year_requested + mon_years;
+ 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. */
+ the remaining code handles overflows correctly. */
/* Calculate day of year from year, month, and day of month.
The result need not be in range. */
- int yday = ((__mon_yday[__isleap (year + TM_YEAR_BASE)]
- [mon_remainder + 12 * negative_mon_remainder])
- + mday - 1);
+ int mon_yday = ((__mon_yday[leapyear (year)]
+ [mon_remainder + 12 * negative_mon_remainder])
+ - 1);
+ long_int lmday = mday;
+ long_int yday = mon_yday + lmday;
+
+ mktime_offset_t off = *offset;
+ int negative_offset_guess;
-#if LEAP_SECONDS_POSSIBLE
- /* Handle out-of-range seconds specially,
- since ydhms_tm_diff assumes every minute has 60 seconds. */
int sec_requested = sec;
- if (sec < 0)
- sec = 0;
- if (59 < sec)
- sec = 59;
-#endif
- /* Invert CONVERT by probing. First assume the same offset as last time.
- Then repeatedly use the error to improve the guess. */
+ if (LEAP_SECONDS_POSSIBLE)
+ {
+ /* Handle out-of-range seconds specially,
+ since ydhms_diff assumes every minute has 60 seconds. */
+ if (sec < 0)
+ sec = 0;
+ if (59 < sec)
+ sec = 59;
+ }
- tm.tm_year = EPOCH_YEAR - TM_YEAR_BASE;
- tm.tm_yday = tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
- t0 = ydhms_tm_diff (year, yday, hour, min, sec, &tm);
+ /* Invert CONVERT by probing. First assume the same offset as last
+ time. */
- for (t = t0 + *offset;
- (dt = ydhms_tm_diff (year, yday, hour, min, sec, (*convert) (&t, &tm)));
- t += dt)
- if (--remaining_probes == 0)
- return -1;
+ INT_SUBTRACT_WRAPV (0, off, &negative_offset_guess);
+ long_int t0 = ydhms_diff (year, yday, hour, min, sec,
+ EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0,
+ negative_offset_guess);
+ long_int t = t0, t1 = t0, t2 = t0;
- /* Check whether tm.tm_isdst has the requested value, if any. */
- if (0 <= isdst && 0 <= tm.tm_isdst)
+ /* Repeatedly use the error to improve the guess. */
+
+ while (true)
{
- int dst_diff = (isdst != 0) - (tm.tm_isdst != 0);
- if (dst_diff)
+ if (! ranged_convert (convert, &t, &tm))
+ return -1;
+ long_int dt = tm_diff (year, yday, hour, min, sec, &tm);
+ if (dt == 0)
+ break;
+
+ 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 DT. Follow the common
+ practice in this case, which is to return a time that is DT
+ 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;
+
+ remaining_probes--;
+ if (remaining_probes == 0)
{
- /* Move two hours in the direction indicated by the disagreement,
- probe some more, and switch to a new time if found.
- The largest known fallback due to daylight savings is two hours:
- once, in Newfoundland, 1988-10-30 02:00 -> 00:00. */
- time_t ot = t - 2 * 60 * 60 * dst_diff;
- while (--remaining_probes != 0)
- {
- struct tm otm;
- if (! (dt = ydhms_tm_diff (year, yday, hour, min, sec,
- (*convert) (&ot, &otm))))
- {
- t = ot;
- tm = otm;
- break;
- }
- if ((ot += dt) == t)
- break; /* Avoid a redundant probe. */
- }
+ __set_errno (EOVERFLOW);
+ return -1;
}
- }
-
- *offset = t - t0;
-#if LEAP_SECONDS_POSSIBLE
- if (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. */
- t += sec_requested - sec + (sec == 0 && tm.tm_sec == 60);
- (*convert) (&t, &tm);
+ t1 = t2, t2 = t, t += dt, dst2 = tm.tm_isdst != 0;
}
-#endif
- if (TIME_T_MAX / INT_MAX / 366 / 24 / 60 / 60 < 3)
+ /* We have a match. Check whether tm.tm_isdst has the requested
+ value, if any. */
+ if (isdst_differ (isdst, tm.tm_isdst))
{
- /* time_t isn't large enough to rule out overflows in ydhms_tm_diff,
- so check for major overflows. A gross check suffices,
- since if t 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. */
+ /* 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)
+ {
+ long_int ot;
+ if (! INT_ADD_WRAPV (t, delta * direction, &ot))
+ {
+ struct tm otm;
+ if (! ranged_convert (convert, &ot, &otm))
+ return -1;
+ if (! isdst_differ (isdst, otm.tm_isdst))
+ {
+ /* We found the desired tm_isdst.
+ Extrapolate back to the desired time. */
+ long_int gt = ot + tm_diff (year, yday, hour, min, sec,
+ &otm);
+ if (mktime_min <= gt && gt <= mktime_max)
+ {
+ if (convert_time (convert, gt, &tm))
+ {
+ t = gt;
+ goto offset_found;
+ }
+ if (errno != EOVERFLOW)
+ return -1;
+ }
+ }
+ }
+ }
+
+ __set_errno (EOVERFLOW);
+ return -1;
+ }
- double dyear = (double) year_requested + mon_years - tm.tm_year;
- double dday = 366 * dyear + mday;
- double dsec = 60 * (60 * (24 * dday + hour) + min) + sec_requested;
+ offset_found:
+ /* Set *OFFSET to the low-order bits of T - T0 - NEGATIVE_OFFSET_GUESS.
+ This is just a heuristic to speed up the next mktime call, and
+ correctness is unaffected if integer overflow occurs here. */
+ INT_SUBTRACT_WRAPV (t, t0, offset);
+ INT_SUBTRACT_WRAPV (*offset, negative_offset_guess, offset);
- if (TIME_T_MAX / 3 - TIME_T_MIN / 3 < (dsec < 0 ? - dsec : dsec))
+ 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. */
+ long_int sec_adjustment = sec == 0 && tm.tm_sec == 60;
+ sec_adjustment -= sec;
+ sec_adjustment += sec_requested;
+ if (INT_ADD_WRAPV (t, sec_adjustment, &t)
+ || ! (mktime_min <= t && t <= mktime_max))
+ {
+ __set_errno (EOVERFLOW);
+ return -1;
+ }
+ if (! convert_time (convert, t, &tm))
return -1;
}
return t;
}
-#ifdef weak_alias
-weak_alias (mktime, timelocal)
-#endif
-\f
-#if DEBUG
-
-static int
-not_equal_tm (a, b)
- struct tm *a;
- 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_mday ^ b->tm_mday)
- | (a->tm_yday ^ b->tm_yday)
- | (a->tm_isdst ^ b->tm_isdst));
-}
+#endif /* _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL */
-static void
-print_tm (tp)
- struct tm *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);
-}
+#if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS
-static int
-check_result (tk, tmk, tl, tml)
- time_t tk;
- struct tm tmk;
- time_t tl;
- struct tm tml;
+/* Convert *TP to a time_t value. */
+time_t
+mktime (struct tm *tp)
{
- if (tk != tl || not_equal_tm (&tmk, &tml))
- {
- printf ("mktime (");
- print_tm (&tmk);
- printf (")\nyields (");
- print_tm (&tml);
- printf (") == %ld, should be %ld\n", (long) tl, (long) tk);
- return 1;
- }
+ /* 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 ();
- return 0;
+# if defined _LIBC || NEED_MKTIME_WORKING
+ static mktime_offset_t localtime_offset;
+ return __mktime_internal (tp, __localtime_r, &localtime_offset);
+# else
+# undef mktime
+ return mktime (tp);
+# endif
}
+#endif /* _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS */
-int
-main (argc, argv)
- int argc;
- char **argv;
-{
- int status = 0;
- struct tm tm, tmk, tml;
- time_t tk, tl;
- 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);
- tml = *localtime (&tl);
- printf ("mktime returns %ld == ", (long) tl);
- print_tm (&tmk);
- printf ("\n");
- status = check_result (tl, tmk, tl, tml);
- }
- 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; tl <= to; tl += by)
- {
- tml = *localtime (&tl);
- tmk = tml;
- tk = mktime (&tmk);
- status |= check_result (tk, tmk, tl, tml);
- }
- else
- for (tl = from; tl <= to; tl += by)
- {
- /* Null benchmark. */
- tml = *localtime (&tl);
- tmk = tml;
- tk = tl;
- status |= check_result (tk, tmk, tl, tml);
- }
- }
- 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;
-}
+#ifdef weak_alias
+weak_alias (mktime, timelocal)
+#endif
-#endif /* DEBUG */
-\f
-/*
-Local Variables:
-compile-command: "gcc -DDEBUG=1 -Wall -O -g mktime.c -o mktime"
-End:
-*/
+#ifdef _LIBC
+libc_hidden_def (mktime)
+libc_hidden_weak (timelocal)
+#endif
projects / thirdparty / glibc.git / blobdiff