-/* Convert a `struct tm' to a time_t value.
- Copyright (C) 1993-1999, 2002, 2003 Free Software Foundation, Inc.
+/* 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).
+ 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
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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ 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
+/* Define this to 1 to have a standalone program to test this implementation of
mktime. */
-/* #define DEBUG 1 */
+#ifndef DEBUG_MKTIME
+# define DEBUG_MKTIME 0
+#endif
+
+/* The following macros influence what gets defined when this file is compiled:
+
+ Macro/expression Which gnulib module This compilation unit
+ should define
+
+ _LIBC (glibc proper) mktime
+
+ NEED_MKTIME_WORKING mktime rpl_mktime
+ || NEED_MKTIME_WINDOWS
+
+ NEED_MKTIME_INTERNAL mktime-internal mktime_internal
+
+ DEBUG_MKTIME (defined manually) my_mktime, main
+ */
-#ifdef HAVE_CONFIG_H
-# include <config.h>
+#if !defined _LIBC && !DEBUG_MKTIME
+# 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
#endif
-#include <sys/types.h> /* Some systems define `time_t' here. */
#include <time.h>
+#include <errno.h>
#include <limits.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
-#if DEBUG
+#include <intprops.h>
+#include <verify.h>
+
+#if DEBUG_MKTIME
# include <stdio.h>
-# include <stdlib.h>
-# include <string.h>
/* Make it work even if the system's libc has its own mktime routine. */
+# undef mktime
# define mktime my_mktime
-#endif /* DEBUG */
-
-/* The extra casts work around common compiler bugs. */
-#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
-/* The outer cast is needed to work around a bug in Cray C 5.0.3.0.
- It is necessary at least when t == time_t. */
-#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
- ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
-#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
-
-#ifndef TIME_T_MIN
-# define TIME_T_MIN TYPE_MINIMUM (time_t)
+#endif /* DEBUG_MKTIME */
+
+#ifndef NEED_MKTIME_INTERNAL
+# define NEED_MKTIME_INTERNAL 0
+#endif
+#ifndef NEED_MKTIME_WINDOWS
+# define NEED_MKTIME_WINDOWS 0
#endif
-#ifndef TIME_T_MAX
-# define TIME_T_MAX TYPE_MAXIMUM (time_t)
+#ifndef NEED_MKTIME_WORKING
+# define NEED_MKTIME_WORKING DEBUG_MKTIME
#endif
-#define TM_YEAR_BASE 1900
-#define EPOCH_YEAR 1970
+#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://msdn.microsoft.com/en-us/library/90s5c885.aspx>
+ - 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 __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))
+#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 EPOCH_YEAR 1970
+#define TM_YEAR_BASE 1900
+verify (TM_YEAR_BASE % 100 == 0);
+
+/* 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
};
-#ifndef _LIBC
-/* Portable standalone applications should supply a "time_r.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. */
-# include "time_r.h"
-# undef __localtime_r
-# define __localtime_r localtime_r
-#endif
+/* 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)
+{
+ 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 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. */
-/* 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 TP is null, return a nonzero value.
- If overflow occurs, yield the low order bits of the correct answer. */
-static time_t
-ydhms_tm_diff (int year, int yday, int hour, int min, int sec,
- const struct tm *tp)
+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)
{
- if (!tp)
- return 1;
- else
- {
- /* 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);
- int a100 = a4 / 25 - (a4 % 25 < 0);
- int b100 = b4 / 25 - (b4 % 25 < 0);
- int a400 = a100 >> 2;
- int b400 = 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));
- }
+ verify (-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 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);
+}
+
+/* Return a long_int value corresponding to (YEAR-YDAY HOUR:MIN:SEC)
+ minus *TP seconds, assuming no clock adjustments occurred between
+ the two timestamps.
+
+ 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)
+{
+ 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. */
+ 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 *),
- time_t *t, struct tm *tp)
+ long_int *t, struct tm *tp)
{
- struct tm *r;
-
- if (! (r = (*convert) (t, tp)) && *t)
+ long_int t1 = (*t < mktime_min ? mktime_min
+ : *t <= mktime_max ? *t : mktime_max);
+ struct tm *r = convert_time (convert, t1, tp);
+ if (r)
{
- time_t bad = *t;
- time_t ok = 0;
- struct tm tm;
-
- /* 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 = (bad < 0
- ? bad + ((ok - bad) >> 1)
- : ok + ((bad - ok) >> 1));
- if ((r = (*convert) (t, tp)))
- {
- tm = *r;
- ok = mid;
- }
- else
- bad = mid;
- }
+ *t = t1;
+ return r;
+ }
+ if (errno != EOVERFLOW)
+ return NULL;
- if (!r && ok)
- {
- /* The last conversion attempt failed;
- revert to the most recent successful attempt. */
- *t = ok;
- *tp = tm;
- r = tp;
- }
+ long_int bad = t1;
+ long_int ok = 0;
+ struct tm oktm; oktm.tm_sec = -1;
+
+ /* 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;
}
- return r;
+ if (oktm.tm_sec < 0)
+ return NULL;
+ *t = ok;
+ *tp = oktm;
+ return tp;
}
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 (struct tm *tp,
struct tm *(*convert) (const time_t *, struct tm *),
- time_t *offset)
+ mktime_offset_t *offset)
{
- time_t t, dt, t0, t1, t2;
struct tm tm;
/* The maximum number of probes (calls to CONVERT) should be enough
int isdst = tp->tm_isdst;
/* 1 if the previous probe was DST. */
- int dst2;
+ 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 sec_requested = sec;
+ int mon_yday = ((__mon_yday[leapyear (year)]
+ [mon_remainder + 12 * negative_mon_remainder])
+ - 1);
+ long_int lmday = mday;
+ long_int yday = mon_yday + lmday;
- /* Only years after 1970 are defined.
- If year is 69, it might still be representable due to
- timezone differences. */
- if (year < 69)
- return -1;
-
-#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;
-#endif
+ mktime_offset_t off = *offset;
+ int negative_offset_guess;
- /* Invert CONVERT by probing. First assume the same offset as last time.
- Then repeatedly use the error to improve the guess. */
-
- 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);
-
- for (t = t1 = t2 = t0 + *offset, dst2 = 0;
- (dt = ydhms_tm_diff (year, yday, hour, min, sec,
- ranged_convert (convert, &t, &tm)));
- t1 = t2, t2 = t, t += dt, 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 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. */
- break;
- else if (--remaining_probes == 0)
- return -1;
+ int sec_requested = sec;
- /* If we have a match, check whether tm.tm_isdst has the requested
- value, if any. */
- if (dt == 0 && isdst != tm.tm_isdst && 0 <= isdst && 0 <= tm.tm_isdst)
+ if (LEAP_SECONDS_POSSIBLE)
{
- /* tm.tm_isdst has the wrong value. Look for a neighboring
- time with the right value, and use its UTC offset.
- Heuristic: probe the previous three calendar quarters (approximately),
- looking for the desired isdst. This isn't perfect,
- but it's good enough in practice. */
- int quarter = 7889238; /* seconds per average 1/4 Gregorian year */
- int i;
+ /* 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;
+ }
- /* If we're too close to the time_t limit, look in future quarters. */
- if (t < TIME_T_MIN + 3 * quarter)
- quarter = -quarter;
+ /* Invert CONVERT by probing. First assume the same offset as last
+ time. */
- for (i = 1; i <= 3; i++)
- {
- time_t ot = t - i * quarter;
- struct tm otm;
- ranged_convert (convert, &ot, &otm);
- if (otm.tm_isdst == isdst)
- {
- /* We found the desired tm_isdst.
- Extrapolate back to the desired time. */
- t = ot + ydhms_tm_diff (year, yday, hour, min, sec, &otm);
- ranged_convert (convert, &t, &tm);
- break;
- }
- }
- }
+ 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;
- *offset = t - t0;
+ /* Repeatedly use the error to improve the guess. */
-#if LEAP_SECONDS_POSSIBLE
- if (sec_requested != tm.tm_sec)
+ while (true)
{
- /* 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);
- if (! (*convert) (&t, &tm))
+ 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)
+ {
+ __set_errno (EOVERFLOW);
+ return -1;
+ }
+
+ 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. */
-
- 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;
-
- /* On Irix4.0.5 cc, dividing TIME_T_MIN by 3 does not produce
- correct results, ie., it erroneously gives a positive value
- of 715827882. Setting a variable first then doing math on it
- seems to work. (ghazi@caip.rutgers.edu) */
+ /* tm.tm_isdst has the wrong value. Look for a neighboring
+ time with the right value, and use its UTC offset.
- const time_t time_t_max = TIME_T_MAX;
- const time_t time_t_min = TIME_T_MIN;
+ 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;
+ }
+ }
+ }
+ }
- if (time_t_max / 3 - time_t_min / 3 < (dsec < 0 ? - dsec : dsec))
- return -1;
+ __set_errno (EOVERFLOW);
+ return -1;
}
- if (year == 69)
+ 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 (LEAP_SECONDS_POSSIBLE && sec_requested != tm.tm_sec)
{
- /* If year was 69, need to check whether the time was representable
- or not. */
- if (t < 0 || t > 2 * 24 * 60 * 60)
+ /* 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;
}
+#endif /* _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL */
-static time_t localtime_offset;
+#if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS
/* 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
+ time zone names contained in the external variable 'tzname' shall
be set as if the tzset() function had been called. */
__tzset ();
-#endif
+# 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 */
#ifdef weak_alias
weak_alias (mktime, timelocal)
libc_hidden_weak (timelocal)
#endif
\f
-#if DEBUG
+#if DEBUG_MKTIME
static int
not_equal_tm (const struct tm *a, const struct tm *b)
| (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));
+ | isdst_differ (a->tm_isdst, b->tm_isdst));
}
static void
time_t tk, tl, tl1;
char trailer;
+ /* Sanity check, plus call tzset. */
+ tl = 0;
+ if (! localtime (&tl))
+ {
+ printf ("localtime (0) fails\n");
+ status = 1;
+ }
+
if ((argc == 3 || argc == 4)
&& (sscanf (argv[1], "%d-%d-%d%c",
&tm.tm_year, &tm.tm_mon, &tm.tm_mday, &trailer)
tm.tm_isdst = argc == 3 ? -1 : atoi (argv[3]);
tmk = tm;
tl = mktime (&tmk);
- lt = localtime (&tl);
- if (lt)
- {
- tml = *lt;
- lt = &tml;
- }
+ lt = localtime_r (&tl, &tml);
printf ("mktime returns %ld == ", (long int) tl);
print_tm (&tmk);
printf ("\n");
if (argc == 4)
for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
{
- lt = localtime (&tl);
+ lt = localtime_r (&tl, &tml);
if (lt)
{
- tmk = tml = *lt;
+ tmk = tml;
tk = mktime (&tmk);
status |= check_result (tk, tmk, tl, &tml);
}
else
{
- printf ("localtime (%ld) yields 0\n", (long int) tl);
+ printf ("localtime_r (%ld) yields 0\n", (long int) tl);
status = 1;
}
tl1 = tl + by;
for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
{
/* Null benchmark. */
- lt = localtime (&tl);
+ lt = localtime_r (&tl, &tml);
if (lt)
{
- tmk = tml = *lt;
+ tmk = tml;
tk = tl;
status |= check_result (tk, tmk, tl, &tml);
}
else
{
- printf ("localtime (%ld) yields 0\n", (long int) tl);
+ printf ("localtime_r (%ld) yields 0\n", (long int) tl);
status = 1;
}
tl1 = tl + by;
return status;
}
-#endif /* DEBUG */
+#endif /* DEBUG_MKTIME */
\f
/*
Local Variables:
-compile-command: "gcc -DDEBUG -DHAVE_TIME_R_POSIX -Wall -W -O -g mktime.c -o mktime"
+compile-command: "gcc -DDEBUG_MKTIME -I. -Wall -W -O2 -g mktime.c -o mktime"
End:
*/
projects / thirdparty / glibc.git / blobdiff