/* Convert a 'struct tm' to a time_t value.
- Copyright (C) 1993-2012 Free Software Foundation, Inc.
+ Copyright (C) 1993-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Eggert <eggert@twinsun.com>.
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/>. */
+ <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:
+
+ 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
+ */
#ifndef _LIBC
-# include <config.h>
+# include <libc-config.h>
#endif
/* Assume that leap seconds are possible, unless told otherwise.
#include <time.h>
+#include <errno.h>
#include <limits.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
-#include <string.h> /* For the real memcpy prototype. */
-
-#if DEBUG
-# 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 */
-
-/* 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
+#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
+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
-/* Verify a requirement at compile-time (unlike assert, which is runtime). */
-#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
+#if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL
-/* A signed type that is at least one bit wider than int. */
-#if INT_MAX <= LONG_MAX / 2
+/* 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 (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
+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. 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.
+ 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. */
-#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)));
+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 (base_year_is_a_multiple_of_100, TM_YEAR_BASE % 100 == 0);
+verify (TM_YEAR_BASE % 100 == 0);
-/* Return 1 if YEAR + TM_YEAR_BASE is a leap year. */
-static inline int
+/* 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.
};
-#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
+/* 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 time stamps.
+ 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 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. */
+ 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 inline time_t
+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 (C99_integer_division, -1 / 2 == 0);
+ 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 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 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;
+ /* 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. */
-static time_t
-time_t_avg (time_t a, time_t b)
+/* 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 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 a long_int value corresponding to (YEAR-YDAY HOUR:MIN:SEC)
+ minus *TP seconds, assuming no clock adjustments occurred between
+ the two timestamps.
-/* Return 1 if A + B does not overflow. */
-static int
-time_t_int_add_ok (time_t a, int b)
+ 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)
{
- 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 ydhms_diff (year, yday, hour, min, sec,
+ tp->tm_year, tp->tm_yday,
+ tp->tm_hour, tp->tm_min, tp->tm_sec);
}
-/* 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)
+/* 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)
{
- 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));
+ 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 = convert (t, tp);
-
- if (!r && *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;
+ *t = t1;
+ return r;
+ }
+ if (errno != EOVERFLOW)
+ return NULL;
- /* 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;
- }
+ long_int bad = t1;
+ long_int ok = 0;
+ struct tm oktm; oktm.tm_sec = -1;
- if (!r && ok)
- {
- /* The last conversion attempt failed;
- revert to the most recent successful attempt. */
- *t = ok;
- r = convert (t, tp);
- }
+ /* 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;
}
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. */
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, gt, 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;
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. */
long_int lmday = mday;
long_int yday = mon_yday + lmday;
- time_t guessed_offset = *offset;
+ 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_tm_diff assumes every minute has 60 seconds. */
+ since ydhms_diff assumes every minute has 60 seconds. */
if (sec < 0)
sec = 0;
if (59 < sec)
/* 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);
+ 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;
+
+ /* Repeatedly use the error to improve the guess. */
- if (TIME_T_MAX / INT_MAX / 366 / 24 / 60 / 60 < 3)
+ while (true)
{
- /* 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)
+ 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)
{
- /* 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;
+ __set_errno (EOVERFLOW);
+ return -1;
}
- }
- /* 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;
+ 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. */
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;
- }
- }
+ {
+ 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;
}
offset_found:
- *offset = guessed_offset + t - t0;
+ /* 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)
{
/* 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))
+ 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;
- t = t2;
}
*tp = tm;
return t;
}
+#endif /* _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL */
-/* 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;
+#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
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_def (mktime)
libc_hidden_weak (timelocal)
#endif
-\f
-#if DEBUG
-
-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 = &tml;
- }
- 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 */
-\f
-/*
-Local Variables:
-compile-command: "gcc -DDEBUG -I. -Wall -W -O2 -g mktime.c -o mktime"
-End:
-*/
projects / thirdparty / glibc.git / blobdiff