Commit e84aba69 authored by Paul Eggert's avatar Paul Eggert
Browse files

* mktime.c: Remove; moving to ../lib.

parent 1e11dbe3
2011-01-09 Paul Eggert <eggert@cs.ucla.edu>
 
* mktime.c: Remove; moving to ../lib.
Use gnulib's mktime module.
* deps.mk (mktime.o): Remove rule.
 
......
/* Convert a `struct tm' to a time_t value.
Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002, 2003,
2004, 2005, 2006, 2007 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@gnu.org.
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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 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 CHAR_BIT
# define CHAR_BIT 8
#endif
/* 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 INT_MIN
# define INT_MIN TYPE_MINIMUM (int)
#endif
#ifndef INT_MAX
# define INT_MAX TYPE_MAXIMUM (int)
#endif
#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 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 }
};
#ifdef _LIBC
# define my_mktime_localtime_r __localtime_r
#else
/* If we're a mktime substitute in a GNU program, then prefer
localtime to localtime_r, since many localtime_r implementations
are buggy. */
static struct tm *
my_mktime_localtime_r (const time_t *t, struct tm *tp)
{
struct tm *l = localtime (t);
if (! l)
return 0;
*tp = *l;
return tp;
}
#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 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)
{
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));
}
}
/* 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. */
static struct tm *
ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
time_t *t, struct tm *tp)
{
struct tm *r;
if (! (r = (*convert) (t, tp)) && *t)
{
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;
}
if (!r && ok)
{
/* The last conversion attempt failed;
revert to the most recent successful attempt. */
*t = ok;
*tp = tm;
r = tp;
}
}
return r;
}
/* 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 (struct tm *tp, struct tm *(*convert) (const time_t *, struct tm *),
time_t *offset)
{
time_t t, dt, t0, t1, t2;
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;
/* 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);
int sec_requested = sec;
/* 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
/* 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;
/* 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)
{
/* 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;
/* If we're too close to the time_t limit, look in future quarters. */
if (t < TIME_T_MIN + 3 * quarter)
quarter = -quarter;
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;
}
}
}
*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);
if (! (*convert) (&t, &tm))
return -1;
}
#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;
/* 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) */
const time_t time_t_max = TIME_T_MAX;
const time_t time_t_min = TIME_T_MIN;
if (time_t_max / 3 - time_t_min / 3 < (dsec < 0 ? - dsec : dsec))
return -1;
}
if (year == 69)
{
/* If year was 69, need to check whether the time was representable
or not. */
if (t < 0 || t > 2 * 24 * 60 * 60)
return -1;
}
*tp = tm;
return t;
}
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, my_mktime_localtime_r, &localtime_offset);
}
#ifdef weak_alias
weak_alias (mktime, timelocal)
#endif
#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;
{
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 (tk, tmk, tl, lt)
time_t tk;
struct tm tmk;
time_t tl;
struct tm *lt;
{
if (tk != tl || !lt || not_equal_tm (&tmk, lt))
{
printf ("mktime (");
print_tm (&tmk);
printf (")\nyields (");
print_tm (lt);
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;
struct tm *lt;
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);
lt = localtime (&tl);
if (lt)
{
tml = *lt;
lt = &tml;
}
printf ("mktime returns %ld == ", (long) 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; tl <= to; tl += by)
{
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) tl);
status = 1;
}
}
else
for (tl = from; tl <= to; tl += by)
{
/* 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) tl);
status = 1;
}
}
}
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 */
/*
Local Variables:
compile-command: "gcc -DDEBUG -DHAVE_LIMITS_H -DSTDC_HEADERS -Wall -W -O -g mktime.c -o mktime"
End:
*/
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