-/* Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
- Contributed by Noel Cragg (noel@cs.oberlin.edu), with fixes by
- Michael E. Calwas (calwas@ttd.teradyne.com) and
- Wade Hampton (tasi029@tmn.com).
-
-This file is part of the GNU C Library.
-
-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.
-
-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.
-
-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., 675 Mass Ave,
-Cambridge, MA 02139, USA. */
-
-/* Define this to have a standalone program to test this implementation of
- mktime. */
-/* #define DEBUG */
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
+/* Convert a 'struct tm' to a time_t value.
+ Copyright (C) 1993-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Paul Eggert <eggert@twinsun.com>.
-#include <sys/types.h> /* Some systems define `time_t' here. */
-#include <time.h>
+ 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.
-#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
+ 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/>. */
-#ifndef __P
-#if defined (__GNUC__) || (defined (__STDC__) && __STDC__)
-#define __P(args) args
-#else
-#define __P(args) ()
-#endif /* GCC. */
-#endif /* Not __P. */
+/* The following macros influence what gets defined when this file is compiled:
-/* How many days are in each month. */
-const unsigned short int __mon_lengths[2][12] =
- {
- /* Normal years. */
- { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
- /* Leap years. */
- { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
- };
+ Macro/expression Which gnulib module This compilation unit
+ should define
+ _LIBC (glibc proper) mktime
-static int times_through_search; /* This library routine should never
- hang -- make sure we always return
- when we're searching for a value */
+ NEED_MKTIME_WORKING mktime rpl_mktime
+ || NEED_MKTIME_WINDOWS
+ NEED_MKTIME_INTERNAL mktime-internal mktime_internal
+ */
-#ifdef DEBUG
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
-#include <stdio.h>
-#include <ctype.h>
+/* 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
-int debugging_enabled = 0;
+#include <time.h>
-/* Print the values in a `struct tm'. */
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <intprops.h>
+#include <verify.h>
+
+#ifndef NEED_MKTIME_INTERNAL
+# define NEED_MKTIME_INTERNAL 0
+#endif
+#ifndef NEED_MKTIME_WINDOWS
+# define NEED_MKTIME_WINDOWS 0
+#endif
+#ifndef NEED_MKTIME_WORKING
+# define NEED_MKTIME_WORKING 0
+#endif
+
+#include "mktime-internal.h"
+
+#if !defined _LIBC && (NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS)
static void
-printtm (it)
- struct tm *it;
+my_tzset (void)
{
- printf ("%02d/%02d/%04d %02d:%02d:%02d (%s) yday:%03d dst:%d gmtoffset:%ld",
- it->tm_mon + 1,
- it->tm_mday,
- it->tm_year + 1900,
- it->tm_hour,
- it->tm_min,
- it->tm_sec,
- it->tm_zone,
- it->tm_yday,
- it->tm_isdst,
- it->tm_gmtoff);
+# 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
+ <https://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
+#if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL
-static time_t
-dist_tm (t1, t2)
- struct tm *t1;
- struct tm *t2;
-{
- time_t distance = 0;
- unsigned long int v1, v2;
- int diff_flag = 0;
-
- v1 = v2 = 0;
-
-#define doit(x, secs) \
- v1 += t1->x * secs; \
- v2 += t2->x * secs; \
- if (!diff_flag) \
- { \
- if (t1->x < t2->x) \
- diff_flag = -1; \
- else if (t1->x > t2->x) \
- diff_flag = 1; \
- }
-
- doit (tm_year, 31536000); /* Okay, not all years have 365 days. */
- doit (tm_mon, 2592000); /* Okay, not all months have 30 days. */
- doit (tm_mday, 86400);
- doit (tm_hour, 3600);
- doit (tm_min, 60);
- doit (tm_sec, 1);
-
-#undef doit
-
- /* We should also make sure that the sign of DISTANCE is correct -- if
- DIFF_FLAG is positive, the distance should be positive and vice versa. */
-
- distance = (v1 > v2) ? (v1 - v2) : (v2 - v1);
- if (diff_flag < 0)
- distance = -distance;
-
- if (times_through_search > 20) /* Arbitrary # of calls, but makes sure we
- never hang if there's a problem with
- this algorithm. */
- {
- distance = diff_flag;
- }
+/* 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 __time64_t values, to
+ lessen the hassle of dealing with platforms where __time64_t is
+ unsigned, and because long_int should suffice to represent all
+ __time64_t values that mktime can generate even on platforms where
+ __time64_t is wider than the int components of struct tm. */
+
+#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);
- /* We need this DIFF_FLAG business because it is forseeable that the
- distance may be zero when, in actuality, the two structures are
- different. This is usually the case when the dates are 366 days apart
- and one of the years is a leap year. */
+/* 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.
- if (distance == 0 && diff_flag)
- distance = 86400 * diff_flag;
+ 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. */
- return distance;
+static long_int
+shr (long_int a, int b)
+{
+ long_int one = 1;
+ return (-one >> 1 == -1
+ ? a >> b
+ : (a + (a < 0)) / (one << b) - (a < 0));
}
-
-/* MKTIME converts the values in a struct tm to a time_t. The values
- in tm_wday and tm_yday are ignored; other values can be put outside
- of legal ranges since they will be normalized. This routine takes
- care of that normalization. */
+/* Bounds for the intersection of __time64_t and long_int. */
-void
-do_normalization (tmptr)
- struct tm *tmptr;
+static long_int const mktime_min
+ = ((TYPE_SIGNED (__time64_t)
+ && TYPE_MINIMUM (__time64_t) < TYPE_MINIMUM (long_int))
+ ? TYPE_MINIMUM (long_int) : TYPE_MINIMUM (__time64_t));
+static long_int const mktime_max
+ = (TYPE_MAXIMUM (long_int) < TYPE_MAXIMUM (__time64_t)
+ ? TYPE_MAXIMUM (long_int) : TYPE_MAXIMUM (__time64_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)));
+}
-#define normalize(foo,x,y,bar); \
- while (tmptr->foo < x) \
- { \
- tmptr->bar--; \
- tmptr->foo = (y - (x - tmptr->foo) + 1); \
- } \
- while (tmptr->foo > y) \
- { \
- tmptr->foo = (x + (tmptr->foo - y) - 1); \
- tmptr->bar++; \
- }
-
- normalize (tm_sec, 0, 59, tm_min);
- normalize (tm_min, 0, 59, tm_hour);
- normalize (tm_hour, 0, 23, tm_mday);
-
- /* Do the month first, so day range can be found. */
- normalize (tm_mon, 0, 11, tm_year);
-
- /* Since the day range modifies the month, we should be careful how
- we reference the array of month lengths -- it is possible that
- the month will go negative, hence the modulo...
-
- Also, tm_year is the year - 1900, so we have to 1900 to have it
- work correctly. */
-
- normalize (tm_mday, 1,
- __mon_lengths[__isleap (tmptr->tm_year + 1900)]
- [((tmptr->tm_mon < 0)
- ? (12 + (tmptr->tm_mon % 12))
- : (tmptr->tm_mon % 12)) ],
- tm_mon);
-
- /* Do the month again, because the day may have pushed it out of range. */
- normalize (tm_mon, 0, 11, tm_year);
-
- /* Do the day again, because the month may have changed the range. */
- normalize (tm_mday, 1,
- __mon_lengths[__isleap (tmptr->tm_year + 1900)]
- [((tmptr->tm_mon < 0)
- ? (12 + (tmptr->tm_mon % 12))
- : (tmptr->tm_mon % 12)) ],
- tm_mon);
-
-#ifdef DEBUG
- if (debugging_enabled)
- {
- printf (" After normalizing:\n ");
- printtm (tmptr);
- putchar ('\n');
- }
+/* 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 }
+ };
+
+/* 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.
-/* Here's where the work gets done. */
+ 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. */
-#define BAD_STRUCT_TM ((time_t) -1)
+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 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 + (a4 < 0)) / 25 - (a4 < 0);
+ int b100 = (b4 + (b4 < 0)) / 25 - (b4 < 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;
+}
-time_t
-_mktime_internal (timeptr, producer)
- struct tm *timeptr;
- struct tm *(*producer) __P ((const time_t *));
+/* 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)
{
- struct tm our_tm; /* our working space */
- struct tm *me = &our_tm; /* a pointer to the above */
- time_t result; /* the value we return */
+ return shr (a, 1) + shr (b, 1) + ((a | b) & 1);
+}
- *me = *timeptr; /* copy the struct tm that was passed
- in by the caller */
+/* 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);
+}
- /***************************/
- /* Normalize the structure */
- /***************************/
+/* Use CONVERT to convert T to a struct tm value in *TM. T must be in
+ range for __time64_t. Return TM if successful, NULL (setting errno) on
+ failure. */
+static struct tm *
+convert_time (struct tm *(*convert) (const __time64_t *, struct tm *),
+ long_int t, struct tm *tm)
+{
+ __time64_t x = t;
+ return convert (&x, tm);
+}
- /* This routine assumes that the value of TM_ISDST is -1, 0, or 1.
- If the user didn't pass it in that way, fix it. */
+/* 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 __time64_t and long_int.
+ Return TP on success, NULL (setting errno) on failure. */
+static struct tm *
+ranged_convert (struct tm *(*convert) (const __time64_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;
- if (me->tm_isdst > 0)
- me->tm_isdst = 1;
- else if (me->tm_isdst < 0)
- me->tm_isdst = -1;
+ long_int bad = t1;
+ long_int ok = 0;
+ struct tm oktm; oktm.tm_sec = -1;
- do_normalization (me);
+ /* 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;
+ }
- /* Get out of here if it's not possible to represent this struct.
- If any of the values in the normalized struct tm are negative,
- our algorithms won't work. Luckily, we only need to check the
- year at this point; normalization guarantees that all values will
- be in correct ranges EXCEPT the year. */
+ if (oktm.tm_sec < 0)
+ return NULL;
+ *t = ok;
+ *tp = oktm;
+ return tp;
+}
- if (me->tm_year < 0)
- return BAD_STRUCT_TM;
- /*************************************************/
- /* Find the appropriate time_t for the structure */
- /*************************************************/
+/* Convert *TP to a __time64_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 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. */
+__time64_t
+__mktime_internal (struct tm *tp,
+ struct tm *(*convert) (const __time64_t *, struct tm *),
+ mktime_offset_t *offset)
+{
+ 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 = 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;
+ 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 overflows correctly. */
+
+ /* 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;
+
+ mktime_offset_t off = *offset;
+ int negative_offset_guess;
+
+ int sec_requested = sec;
+
+ 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;
+ }
- /* Modified b-search -- make intelligent guesses as to where the
- time might lie along the timeline, assuming that our target time
- lies a linear distance (w/o considering time jumps of a
- particular region).
+ /* Invert CONVERT by probing. First assume the same offset as last
+ time. */
- Assume that time does not fluctuate at all along the timeline --
- e.g., assume that a day will always take 86400 seconds, etc. --
- and come up with a hypothetical value for the time_t
- representation of the struct tm TARGET, in relation to the guess
- variable -- it should be pretty close!
+ 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;
- After testing this, the maximum number of iterations that I had
- on any number that I tried was 3! Not bad.
+ /* Repeatedly use the error to improve the guess. */
- The reason this is not a subroutine is that we will modify some
- fields in the struct tm (yday and mday). I've never felt good
- about side-effects when writing structured code... */
+ while (true)
+ {
+ 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;
+ }
- {
- struct tm *guess_tm;
- time_t guess = 0;
- time_t distance = 0;
- time_t last_distance = 0;
-
- times_through_search = 0;
-
- do
- {
- guess += distance;
-
- times_through_search++;
-
- guess_tm = (*producer) (&guess);
-
-#ifdef DEBUG
- if (debugging_enabled)
- {
- printf (" Guessing time_t == %d\n ", (int) guess);
- printtm (guess_tm);
- putchar ('\n');
- }
-#endif
-
- /* How far is our guess from the desired struct tm? */
- distance = dist_tm (me, guess_tm);
-
- /* Handle periods of time where a period of time is skipped.
- For example, 2:15 3 April 1994 does not exist, because DST
- is in effect. The distance function will alternately
- return values of 3600 and -3600, because it doesn't know
- that the requested time doesn't exist. In these situations
- (even if the skip is not exactly an hour) the distances
- returned will be the same, but alternating in sign. We
- want the later time, so check to see that the distance is
- oscillating and we've chosen the correct of the two
- possibilities.
-
- Useful: 3 Apr 94 765356300, 30 Oct 94 783496000 */
-
- if ((distance == -last_distance) && (distance < last_distance))
+ t1 = t2, t2 = t, t += dt, dst2 = tm.tm_isdst != 0;
+ }
+
+ /* 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 the caller specified that the DST flag was off, it's
- not possible to represent this time. */
- if (me->tm_isdst == 0)
+ long_int ot;
+ if (! INT_ADD_WRAPV (t, delta * direction, &ot))
{
-#ifdef DEBUG
- printf (" Distance is oscillating -- dst flag nixes struct!\n");
-#endif
- return BAD_STRUCT_TM;
+ 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;
+ }
+ }
}
-
-#ifdef DEBUG
- printf (" Distance is oscillating -- chose the later time.\n");
-#endif
- distance = 0;
- }
-
- if ((distance == 0) && (me->tm_isdst != -1)
- && (me->tm_isdst != guess_tm->tm_isdst))
- {
- /* If we're in this code, we've got the right time but the
- wrong daylight savings flag. We need to move away from
- the time that we have and approach the other time from
- the other direction. That is, if I've requested the
- non-DST version of a time and I get the DST version
- instead, I want to put us forward in time and search
- backwards to get the other time. I checked all of the
- configuration files for the tz package -- no entry
- saves more than two hours, so I think we'll be safe by
- moving 24 hours in one direction. IF THE AMOUNT OF
- TIME SAVED IN THE CONFIGURATION FILES CHANGES, THIS
- VALUE MAY NEED TO BE ADJUSTED. Luckily, we can never
- have more than one level of overlaps, or this would
- never work. */
-
-#define SKIP_VALUE 86400
-
- if (guess_tm->tm_isdst == 0)
- /* we got the later one, but want the earlier one */
- distance = -SKIP_VALUE;
- else
- distance = SKIP_VALUE;
-
-#ifdef DEBUG
- printf (" Got the right time, wrong DST value -- adjusting\n");
-#endif
}
- last_distance = distance;
-
- } while (distance != 0);
+ __set_errno (EOVERFLOW);
+ return -1;
+ }
- /* Check to see that the dst flag matches */
+ 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 (me->tm_isdst != -1)
- {
- if (me->tm_isdst != guess_tm->tm_isdst)
- {
-#ifdef DEBUG
- printf (" DST flag doesn't match! FIXME?\n");
-#endif
- return BAD_STRUCT_TM;
- }
- }
+ 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;
+ }
- result = guess; /* Success! */
+ *tp = tm;
+ return t;
+}
- /* On successful completion, the values of tm_wday and tm_yday
- have to be set appropriately. */
-
- /* me->tm_yday = guess_tm->tm_yday;
- me->tm_mday = guess_tm->tm_mday; */
+#endif /* _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL */
- *me = *guess_tm;
- }
+#if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS
- /* Update the caller's version of the structure */
+/* Convert *TP to a __time64_t value. */
+__time64_t
+__mktime64 (struct tm *tp)
+{
+ /* 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 ();
+
+# if defined _LIBC || NEED_MKTIME_WORKING
+ static mktime_offset_t localtime_offset;
+ return __mktime_internal (tp, __localtime64_r, &localtime_offset);
+# else
+# undef mktime
+ return mktime (tp);
+# endif
+}
+#endif /* _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS */
- *timeptr = *me;
+#if defined _LIBC && __TIMESIZE != 64
- return result;
-}
+libc_hidden_def (__mktime64)
time_t
-#ifdef DEBUG /* make it work even if the system's
- libc has it's own mktime routine */
-my_mktime (timeptr)
-#else
-mktime (timeptr)
-#endif
- struct tm *timeptr;
-{
- return _mktime_internal (timeptr, localtime);
-}
-
-#ifdef weak_alias
-weak_alias (mktime, timelocal)
-#endif
-\f
-#ifdef DEBUG
-void
-main (argc, argv)
- int argc;
- char *argv[];
+mktime (struct tm *tp)
{
- int time;
- int result_time;
- struct tm *tmptr;
-
- if (argc == 1)
+ struct tm tm = *tp;
+ __time64_t t = __mktime64 (&tm);
+ if (in_time_t_range (t))
{
- long q;
-
- printf ("starting long test...\n");
-
- for (q = 10000000; q < 1000000000; q += 599)
- {
- struct tm *tm = localtime ((time_t *) &q);
- if ((q % 10000) == 0) { printf ("%ld\n", q); fflush (stdout); }
- if (q != my_mktime (tm))
- { printf ("failed for %ld\n", q); fflush (stdout); }
- }
-
- printf ("test finished\n");
-
- exit (0);
+ *tp = tm;
+ return t;
}
-
- if (argc != 2)
+ else
{
- printf ("wrong # of args\n");
- exit (0);
+ __set_errno (EOVERFLOW);
+ return -1;
}
-
- debugging_enabled = 1; /* We want to see the info */
-
- ++argv;
- time = atoi (*argv);
-
- tmptr = localtime ((time_t *) &time);
- printf ("Localtime tells us that a time_t of %d represents\n ", time);
- printtm (tmptr);
- putchar ('\n');
-
- printf (" Given localtime's return val, mktime returns %d which is\n ",
- (int) my_mktime (tmptr));
- printtm (tmptr);
- putchar ('\n');
-
-#if 0
- tmptr->tm_sec -= 20;
- tmptr->tm_min -= 20;
- tmptr->tm_hour -= 20;
- tmptr->tm_mday -= 20;
- tmptr->tm_mon -= 20;
- tmptr->tm_year -= 20;
- tmptr->tm_gmtoff -= 20000; /* This has no effect! */
- tmptr->tm_zone = NULL; /* Nor does this! */
- tmptr->tm_isdst = -1;
-#endif
-
- tmptr->tm_hour += 1;
- tmptr->tm_isdst = -1;
-
- printf ("\n\nchanged ranges: ");
- printtm (tmptr);
- putchar ('\n');
-
- result_time = my_mktime (tmptr);
- printf ("\nmktime: %d\n", result_time);
-
- tmptr->tm_isdst = 0;
+}
- printf ("\n\nchanged ranges: ");
- printtm (tmptr);
- putchar ('\n');
+#endif
- result_time = my_mktime (tmptr);
- printf ("\nmktime: %d\n", result_time);
-}
-#endif /* DEBUG */
-
-\f
-/*
-Local Variables:
-compile-command: "gcc -g mktime.c -o mktime -DDEBUG"
-End:
-*/
+weak_alias (mktime, timelocal)
+libc_hidden_def (mktime)
+libc_hidden_weak (timelocal)
projects / thirdparty / glibc.git / blobdiff