--- /dev/null
+/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
+ Contributed by Paul Eggert (eggert@twinsun.com).
+
+ NOTE: The canonical source of this file is maintained with the GNU C Library.
+ Bugs can be reported to bug-glibc@prep.ai.mit.edu.
+
+ This program is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by the
+ Free Software Foundation; either version 2, or (at your option) any
+ later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if 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 1 */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#ifdef _LIBC
+# define HAVE_LIMITS_H 1
+# define HAVE_LOCALTIME_R 1
+# define STDC_HEADERS 1
+#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 HAVE_LIMITS_H
+#include <limits.h>
+#endif
+
+#if DEBUG
+#include <stdio.h>
+#if 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__)
+#define __P(args) args
+#else
+#define __P(args) ()
+#endif /* GCC. */
+#endif /* Not __P. */
+
+#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
+
+#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
+
+#define TM_YEAR_BASE 1900
+#define EPOCH_YEAR 1970
+
+#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
+
+/* 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 }
+ };
+
+static time_t ydhms_tm_diff __P ((int, int, int, int, int, const struct tm *));
+time_t __mktime_internal __P ((struct tm *,
+ struct tm *(*) (const time_t *, struct tm *),
+ time_t *));
+
+
+#ifdef _LIBC
+#define localtime_r __localtime_r
+#else
+#if ! HAVE_LOCALTIME_R && ! defined (localtime_r)
+/* Approximate localtime_r as best we can in its absence. */
+#define localtime_r my_localtime_r
+static struct tm *localtime_r __P ((const time_t *, struct tm *));
+static struct tm *
+localtime_r (t, tp)
+ const time_t *t;
+ struct tm *tp;
+{
+ struct tm *l = localtime (t);
+ if (! l)
+ return 0;
+ *tp = *l;
+ return tp;
+}
+#endif /* ! HAVE_LOCALTIME_R && ! defined (localtime_r) */
+#endif /* ! _LIBC */
+
+
+/* Yield the difference between (YEAR-YDAY HOUR:MIN:SEC) and (*TP),
+ measured in seconds, ignoring leap seconds.
+ YEAR uses the same numbering as TM->tm_year.
+ All values are in range, except possibly YEAR.
+ If overflow occurs, yield the low order bits of the correct answer. */
+static time_t
+ydhms_tm_diff (year, yday, hour, min, sec, tp)
+ int year, yday, hour, min, sec;
+ const struct tm *tp;
+{
+ /* 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));
+}
+
+
+static time_t localtime_offset;
+
+/* Convert *TP to a time_t value. */
+time_t
+mktime (tp)
+ 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
+
+ return __mktime_internal (tp, localtime_r, &localtime_offset);
+}
+
+/* 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
+
+ /* 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 = t0 + *offset;
+ (dt = ydhms_tm_diff (year, yday, hour, min, sec, (*convert) (&t, &tm)));
+ t += dt)
+ if (--remaining_probes == 0)
+ return -1;
+
+ /* Check whether tm.tm_isdst has the requested value, if any. */
+ if (0 <= isdst && 0 <= tm.tm_isdst)
+ {
+ int dst_diff = (isdst != 0) - (tm.tm_isdst != 0);
+ if (dst_diff)
+ {
+ /* 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. */
+ }
+ }
+ }
+
+ *offset = t - t0;
+
+#if LEAP_SECONDS_POSSIBLE
+ if (sec_requested != tm.tm_sec)
+ {
+ /* Adjust time to reflect the tm_sec requested, not the normalized value.
+ Also, repair any damage from a false match due to a leap second. */
+ t += sec_requested - sec + (sec == 0 && tm.tm_sec == 60);
+ (*convert) (&t, &tm);
+ }
+#endif
+
+ 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;
+ }
+
+ *tp = tm;
+ return t;
+}
+
+#ifdef weak_alias
+weak_alias (mktime, timelocal)
+#endif
+\f
+#if DEBUG
+
+static int
+not_equal_tm (a, b)
+ struct tm *a;
+ struct tm *b;
+{
+ return ((a->tm_sec ^ b->tm_sec)
+ | (a->tm_min ^ b->tm_min)
+ | (a->tm_hour ^ b->tm_hour)
+ | (a->tm_mday ^ b->tm_mday)
+ | (a->tm_mon ^ b->tm_mon)
+ | (a->tm_year ^ b->tm_year)
+ | (a->tm_mday ^ b->tm_mday)
+ | (a->tm_yday ^ b->tm_yday)
+ | (a->tm_isdst ^ b->tm_isdst));
+}
+
+static void
+print_tm (tp)
+ struct tm *tp;
+{
+ printf ("%04d-%02d-%02d %02d:%02d:%02d yday %03d wday %d isdst %d",
+ tp->tm_year + TM_YEAR_BASE, tp->tm_mon + 1, tp->tm_mday,
+ tp->tm_hour, tp->tm_min, tp->tm_sec,
+ tp->tm_yday, tp->tm_wday, tp->tm_isdst);
+}
+
+static int
+check_result (tk, tmk, tl, tml)
+ time_t tk;
+ struct tm tmk;
+ time_t tl;
+ struct tm tml;
+{
+ if (tk != tl || not_equal_tm (&tmk, &tml))
+ {
+ printf ("mktime (");
+ print_tm (&tmk);
+ printf (")\nyields (");
+ print_tm (&tml);
+ printf (") == %ld, should be %ld\n", (long) tl, (long) tk);
+ return 1;
+ }
+
+ return 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);
+ }
+ else if (argc == 4 || (argc == 5 && strcmp (argv[4], "-") == 0))
+ {
+ time_t from = atol (argv[1]);
+ time_t by = atol (argv[2]);
+ time_t to = atol (argv[3]);
+
+ if (argc == 4)
+ for (tl = from; tl <= to; tl += by)
+ {
+ tml = *localtime (&tl);
+ tmk = tml;
+ tk = mktime (&tmk);
+ status |= check_result (tk, tmk, tl, tml);
+ }
+ else
+ for (tl = from; tl <= to; tl += by)
+ {
+ /* Null benchmark. */
+ tml = *localtime (&tl);
+ tmk = tml;
+ tk = tl;
+ status |= check_result (tk, tmk, tl, tml);
+ }
+ }
+ else
+ printf ("Usage:\
+\t%s YYYY-MM-DD HH:MM:SS [ISDST] # Test given time.\n\
+\t%s FROM BY TO # Test values FROM, FROM+BY, ..., TO.\n\
+\t%s FROM BY TO - # Do not test those values (for benchmark).\n",
+ argv[0], argv[0], argv[0]);
+
+ return status;
+}
+
+#endif /* DEBUG */
+\f
+/*
+Local Variables:
+compile-command: "gcc -DDEBUG=1 -Wall -O -g mktime.c -o mktime"
+End:
+*/
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