-/* Copyright (C) 1993, 1994 Free Software Foundation, Inc.
- Contributed by Noel Cragg (noel@cs.oberlin.edu).
+/* Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
+ Contributed by Paul Eggert (eggert@twinsun.com).
This file is part of the GNU C Library.
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. */
+not, write to the Free Software Foundation, Inc., 59 Temple Place -
+Suite 330, Boston, MA 02111-1307, USA. */
/* Define this to have a standalone program to test this implementation of
mktime. */
-/* #define DEBUG */
+/* #define DEBUG 1 */
#ifdef HAVE_CONFIG_H
-#if defined (CONFIG_BROKETS)
-/* We use <config.h> instead of "config.h" so that a compilation
- using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h
- (which it would do because it found this file in $srcdir). */
#include <config.h>
-#else
-#include "config.h"
#endif
+
+/* Assume that leap seconds are possible, unless told otherwise.
+ If the host has a `zic' command with a `-L leapsecondfilename' option,
+ then it supports leap seconds; otherwise it probably doesn't. */
+#ifndef LEAP_SECONDS_POSSIBLE
+#define LEAP_SECONDS_POSSIBLE 1
#endif
#include <sys/types.h> /* Some systems define `time_t' here. */
#include <time.h>
+#if __STDC__ || __GNU_LIBRARY__ || STDC_HEADERS
+#include <limits.h>
+#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 DEBUG
+#include <stdio.h>
+#if __STDC__ || __GNU_LIBRARY__ || STDC_HEADERS
+#include <stdlib.h>
#endif
+/* Make it work even if the system's libc has its own mktime routine. */
+#define mktime my_mktime
+#endif /* DEBUG */
#ifndef __P
#if defined (__GNUC__) || (defined (__STDC__) && __STDC__)
#endif /* GCC. */
#endif /* Not __P. */
-/* 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 }
- };
+#ifndef CHAR_BIT
+#define CHAR_BIT 8
+#endif
+#ifndef INT_MIN
+#define INT_MIN (~0 << (sizeof (int) * CHAR_BIT - 1))
+#endif
+#ifndef INT_MAX
+#define INT_MAX (~0 - INT_MIN)
+#endif
-static int times_through_search; /* This library routine should never
- hang -- make sure we always return
- when we're searching for a value */
+#ifndef TIME_T_MIN
+#define TIME_T_MIN (0 < (time_t) -1 ? (time_t) 0 \
+ : ~ (time_t) 0 << (sizeof (time_t) * CHAR_BIT - 1))
+#endif
+#ifndef TIME_T_MAX
+#define TIME_T_MAX (~ (time_t) 0 - TIME_T_MIN)
+#endif
-/* After testing this, the maximum number of iterations that I had on
- any number that I tried was 3! Not bad.
+#define TM_YEAR_BASE 1900
+#define EPOCH_YEAR 1970
- mktime converts a `struct tm' (broken-down local time) into a `time_t';
- it is the opposite of localtime. It is possible to put the following
- values out of range and have mktime compensate: tm_sec, tm_min, tm_hour,
- tm_mday, tm_year. The other values in the structure are ignored. */
+#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
-#ifdef DEBUG
+/* How many days come before each month (0-12). */
+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 }
+ };
-#include <stdio.h>
-#include <ctype.h>
+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 *));
-int debugging_enabled = 0;
-/* Print the values in a `struct tm'. */
-static void
-printtm (it)
- struct tm *it;
+#if ! HAVE_LOCALTIME_R && ! defined (localtime_r)
+#ifdef _LIBC
+#define localtime_r __localtime_r
+#else
+/* 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;
{
- printf ("%d/%d/%d %d:%d:%d (%s) yday:%d f:%d o:%ld",
- it->tm_mon,
- it->tm_mday,
- it->tm_year,
- it->tm_hour,
- it->tm_min,
- it->tm_sec,
- it->tm_zone,
- it->tm_yday,
- it->tm_isdst,
- it->tm_gmtoff);
+ struct tm *l = localtime (t);
+ if (! l)
+ return 0;
+ *tp = *l;
+ return tp;
}
-#endif
+#endif /* ! _LIBC */
+#endif /* ! HAVE_LOCALTIME_R && ! defined (localtime_r) */
+/* 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
-dist_tm (t1, t2)
- struct tm *t1;
- struct tm *t2;
+ydhms_tm_diff (year, yday, hour, min, sec, tp)
+ int year, yday, hour, min, sec;
+ const struct tm *tp;
{
- 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;
- }
-
- /* 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. */
+ time_t ay = year + (time_t) (TM_YEAR_BASE - 1);
+ time_t by = tp->tm_year + (time_t) (TM_YEAR_BASE - 1);
+ time_t intervening_leap_days =
+ (ay/4 - by/4) - (ay/100 - by/100) + (ay/400 - by/400);
+ time_t years = ay - by;
+ 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));
+}
- if (distance == 0 && diff_flag)
- distance = 86400 * diff_flag;
- return distance;
+/* Convert *TP to a time_t value. */
+time_t
+mktime (tp)
+ struct tm *tp;
+{
+ static time_t localtime_offset;
+ return __mktime_internal (tp, localtime_r, &localtime_offset);
}
-
-/* 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).
+/* 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. */
+time_t
+__mktime_internal (tp, convert, offset)
+ struct tm *tp;
+ struct tm *(*convert) __P ((const time_t *, struct tm *));
+ time_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;
+
+ /* 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;
+
+ /* 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;
+
+ /* The other values need not be in range:
+ the remaining code handles minor overflows correctly,
+ assuming int and time_t arithmetic wraps around.
+ Major overflows are caught at the end. */
+
+ /* Calculate day of year from year, month, and day of month.
+ The result need not be in range. */
+ int yday = ((__mon_yday[__isleap (year + TM_YEAR_BASE)]
+ [mon_remainder + 12 * negative_mon_remainder])
+ + mday - 1);
+
+#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
- 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! */
+ /* Invert CONVERT by probing. First assume the same offset as last time.
+ Then repeatedly use the error to improve the guess. */
-static time_t
-search (target, producer)
- struct tm *target;
- struct tm *(*producer) __P ((const time_t *));
-{
- struct tm *guess_tm;
- time_t guess = 0;
- time_t distance = 0;
+ 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);
- times_through_search = 0;
+ for (t = t0 + *offset;
+ (dt = ydhms_tm_diff (year, yday, hour, min, sec, (*convert) (&t, &tm)));
+ t += dt)
+ if (--remaining_probes == 0)
+ return -1;
- do
+ /* Check whether tm.tm_isdst has the requested value, if any. */
+ if (0 <= isdst && 0 <= tm.tm_isdst)
{
- guess += distance;
-
- times_through_search++;
-
- guess_tm = (*producer) (&guess);
-
-#ifdef DEBUG
- if (debugging_enabled)
+ int dst_diff = (isdst != 0) - (tm.tm_isdst != 0);
+ if (dst_diff)
{
- printf ("guess %d == ", (int) guess);
- printtm (guess_tm);
- puts ("");
+ /* 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. */
+ }
}
-#endif
-
- /* Are we on the money? */
- distance = dist_tm (target, guess_tm);
-
- } while (distance != 0);
-
- return guess;
-}
+ }
-/* Since this function will call localtime many times (and the user might
- be passing their `struct tm *' right from localtime, let's make a copy
- for ourselves and run the search on the copy.
+ *offset = t - t0;
- Also, we have to normalize *TIMEPTR because it's possible to call mktime
- with values that are out of range for a specific item (like Feb 30th). */
-time_t
-_mktime_internal (timeptr, producer)
- struct tm *timeptr;
- struct tm *(*producer) __P ((const time_t *));
-{
- struct tm private_mktime_struct_tm; /* Yes, users can get a ptr to this. */
- struct tm *me;
- time_t result;
-
- me = &private_mktime_struct_tm;
-
- *me = *timeptr;
-
-#define normalize(foo,x,y,bar); \
- while (me->foo < x) \
- { \
- me->bar--; \
- me->foo = (y - (x - me->foo)); \
- } \
- while (me->foo > y) \
- { \
- me->bar++; \
- me->foo = (x + (me->foo - y)); \
- }
-
- 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);
- normalize (tm_mday, 1,
- __mon_lengths[__isleap (me->tm_year)][me->tm_mon],
- 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 (me->tm_year)][me->tm_mon],
- tm_mon);
-
-#ifdef DEBUG
- if (debugging_enabled)
+#if LEAP_SECONDS_POSSIBLE
+ if (sec_requested != tm.tm_sec)
{
- printf ("After normalizing: ");
- printtm (me);
- puts ("\n");
+ /* 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);
}
#endif
- result = search (me, producer);
+ if (TIME_T_MAX / INT_MAX / 366 / 24 / 60 / 60 < 3)
+ {
+ /* 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;
+
+ if (TIME_T_MAX / 3 - TIME_T_MIN / 3 < (dsec < 0 ? - dsec : dsec))
+ return -1;
+ }
- *timeptr = *me;
+ *tp = tm;
+ return t;
+}
- return result;
+#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));
}
-time_t
-mktime (timeptr)
- struct tm *timeptr;
+static void
+print_tm (tp)
+ struct tm *tp;
{
- return _mktime_internal (timeptr, localtime);
+ 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);
}
-\f
-#ifdef DEBUG
-void
-main (argc, argv)
- int argc;
- char *argv[];
+
+static int
+check_result (tk, tmk, tl, tml)
+ time_t tk;
+ struct tm tmk;
+ time_t tl;
+ struct tm tml;
{
- int time;
- int result_time;
- struct tm *tmptr;
-
- if (argc == 1)
+ if (tk != tl || not_equal_tm (&tmk, &tml))
{
- long q;
-
- printf ("starting long test...\n");
+ printf ("mktime (");
+ print_tm (&tmk);
+ printf (")\nyields (");
+ print_tm (&tml);
+ printf (") == %ld, should be %ld\n", (long) tl, (long) tk);
+ return 1;
+ }
- for (q = 10000000; q < 1000000000; q++)
- {
- struct tm *tm = localtime (&q);
- if ((q % 10000) == 0) { printf ("%ld\n", q); fflush (stdout); }
- if (q != mktime (tm))
- { printf ("failed for %ld\n", q); fflush (stdout); }
- }
-
- printf ("test finished\n");
+ return 0;
+}
- exit (0);
+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);
}
-
- if (argc != 2)
+ else if (argc == 4 || (argc == 5 && strcmp (argv[4], "-") == 0))
{
- printf ("wrong # of args\n");
- exit (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);
+ }
}
-
- debugging_enabled = 1; /* We want to see the info */
-
- ++argv;
- time = atoi (*argv);
-
- printf ("Time: %d %s\n", time, ctime ((time_t *) &time));
-
- tmptr = localtime ((time_t *) &time);
- printf ("localtime returns: ");
- printtm (tmptr);
- printf ("\n");
- printf ("mktime: %d\n\n", (int) mktime (tmptr));
-
- 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;
-
- printf ("changed ranges: ");
- printtm (tmptr);
- printf ("\n\n");
-
- result_time = mktime (tmptr);
- printf ("\nmktime: %d\n", result_time);
+ 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=1 -Wall -O -g mktime.c -o mktime"
+End:
+*/
projects / gnulib.git / blobdiff