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flightgear/src/Time/lowleveltime.cxx

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/* -*- Mode: C++ -*- *****************************************************
* Written by various people (I"ll look up the exact credits later)
* Modified by Durk Talsma, July 1999 for use in FlightGear
*
* 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 of the
* License, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
**************************************************************************/
/********************************************************************
* This file redefines some low-level Unix-like time functions for *
* use with FlightGear. Most notably, localtime() is adapted to use *
* a custom timezone, in order to get the 'local' time for a given *
* aircraft's position, and not only for the current location of the*
* computer running the sim. *
* *
* Software adapted from glibc functions, by Durk Talsma. Started *
* July, 17, 1999. *
********************************************************************/
#include <time.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
//#include <libc-lock.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include "lowleveltime.h"
/* BIG FAT WARNING: NOTICE THAT I HARDCODED ENDIANNES. PLEASE CHANGE THIS */
#ifndef BIG_ENDIAN
#define BIG_ENDIAN 4321
#endif
#ifndef LITTLE_ENDIAN
#define LITTLE_ENDIAN 1234
#endif
#ifndef BYTE_ORDER
#define BYTE_ORDER LITTLE_ENDIAN
#endif
#ifndef BYTE_ORDER
#define BYTE_ORDER
#endif
/* END OF BIG FAT WARNING */
//#include "tzfile.h"
#define min(a, b) ((a) < (b) ? (a) : (b))
#define max(a, b) ((a) > (b) ? (a) : (b))
#define sign(x) ((x) < 0 ? -1 : 1)
struct leap
{
time_t transition; /* Time the transition takes effect. */
long int change; /* Seconds of correction to apply. */
};
/* Header for a list of buffers containing time zone strings. */
struct tzstring_head
{
struct tzstring_head *next;
/* The buffer itself immediately follows the header.
The buffer contains zero or more (possibly overlapping) strings.
The last string is followed by 2 '\0's instead of the usual 1. */
};
/* First in a list of buffers containing time zone strings.
All the buffers but the last are read-only. */
static struct
{
struct tzstring_head head;
char data[48];
} tzstring_list;
/* Size of the last buffer in the list, not counting its header. */
static size_t tzstring_last_buffer_size = sizeof tzstring_list.data;
static char *old_fgtz = NULL;
static int use_fgtzfile = 1;
static int fgdaylight;
static char* fgtzname[2];
static long int fgtimezone;
static size_t num_transitions;
static time_t *transitions = NULL;
static unsigned char *type_idxs = NULL;
static size_t num_types;
static struct ttinfo *types = NULL;
static char *zone_names = NULL;
static size_t num_leaps;
static struct leap *leaps = NULL;
static void fgtzset_internal (int always, const char *tz);
static int fgtz_compute(time_t timer, const struct tm *tm);
static int fgcompute_change(fgtz_rule *rule, int year);
static struct ttinfo *fgfind_transition (time_t timer);
static void fgcompute_tzname_max (size_t chars);
static inline int decode (const void *ptr);
void fgtzfile_read (const char *file);
static void offtime (const time_t *t, long int offset, struct tm *tp);
static char *tzstring (const char* string);
/* tz_rules[0] is standard, tz_rules[1] is daylight. */
static fgtz_rule fgtz_rules[2];
int fgtzfile_compute (time_t timer, int use_localtime,
long int *leap_correct, int *leap_hit);
struct ttinfo
{
long int offset; /* Seconds east of GMT. */
unsigned char isdst; /* Used to set tm_isdst. */
unsigned char idx; /* Index into `zone_names'. */
unsigned char isstd; /* Transition times are in standard time. */
unsigned char isgmt; /* Transition times are in GMT. */
};
/* 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 }
};
/* The C Standard says that localtime and gmtime return the same pointer. */
struct tm _fgtmbuf;
#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
/* Return the `struct tm' representation of *T in local time. */
struct tm * fgLocaltime (const time_t *t, const char *tzName)
{
return fgtz_convert (t, 1, &_fgtmbuf, tzName);
}
/* Return the `struct tm' representation of *TIMER in the local timezone.
Use local time if USE_LOCALTIME is nonzero, UTC otherwise. */
struct tm * fgtz_convert (const time_t *timer, int use_localtime, struct tm *tp, const char *tzName)
{
long int leap_correction;
long int offsetCorr; // ADDED TO RESOLVE NON-ANSI FIELDS IN struct tm
int leap_extra_secs;
if (timer == NULL)
{
//set_errno (EINVAL);
return NULL;
}
//libc_lock_lock (tzset_lock);
/* Update internal database according to current TZ setting.
POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname.
This is a good idea since this allows at least a bit more parallelism.
By analogy we apply the same rule to gmtime_r. */
fgtzset_internal (tp == &_fgtmbuf, tzName);
if (use_fgtzfile)
{
if (! fgtzfile_compute (*timer, use_localtime,
&leap_correction, &leap_extra_secs))
tp = NULL;
}
else
{
offtime (timer, 0, tp);
if (! fgtz_compute (*timer, tp))
tp = NULL;
leap_correction = 0L;
leap_extra_secs = 0;
}
if (tp)
{
if (use_localtime)
{
tp->tm_isdst = fgdaylight;
//tp->tm_zone = fgtzname[fgdaylight]; // NON_ANSI
//tp->tm_gmtoff = -fgtimezone; // NON_ANSI
offsetCorr = -fgtimezone;
}
else
{
tp->tm_isdst = 0;
//tp->tm_zone = "GMT"; // NON_ANSI
//tp->tm_gmtoff = 0L; // NON_ANSI
offsetCorr = -fgtimezone;
}
//offtime (timer, tp->tm_gmtoff - leap_correction, tp);
offtime (timer, offsetCorr - leap_correction, tp);
tp->tm_sec += leap_extra_secs;
}
//libc_lock_unlock (tzset_lock);
return tp;
}
/* the following stuff is adapted from the tzCode package */
static size_t longest;
static char * abbr (struct tm * tmp);
void show(const char *zone, time_t t, int v)
{
struct tm * tmp;
(void) printf("%-*s ", (int) longest, zone);
if (v)
(void) printf("%.24s UTC = ", asctime(gmtime(&t)));
tmp = fgLocaltime(&t, zone);
(void) printf("%.24s", asctime(tmp));
if (*abbr(tmp) != '\0')
(void) printf(" %s", abbr(tmp));
if (v) {
(void) printf(" isdst=%d", tmp->tm_isdst);
#ifdef TM_GMTOFF
(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
#endif /* defined TM_GMTOFF */
}
(void) printf("\n");
}
static char *abbr(struct tm *tmp)
{
register char * result;
static char nada;
if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
return &nada;
result = fgtzname[tmp->tm_isdst];
return (result == NULL) ? &nada : result;
}
/***********************************************************************/
/* Interpret the TZ envariable. */
static void fgtzset_internal (int always, const char *tz)
{
time_t now;
time(&now);
static int is_initialized = 0;
//register const char *tz;
register size_t l;
char *tzbuf;
unsigned short int hh, mm, ss;
unsigned short int whichrule;
if (is_initialized && !always)
return;
is_initialized = 1;
/* Examine the TZ environment variable. */
//tz = getenv ("TZ");
if (tz == NULL)
/* No user specification; use the site-wide default. */
tz = TZDEFAULT;
else if (*tz == '\0')
/* User specified the empty string; use UTC explicitly. */
tz = "Universal";
#ifdef MACOS
/* as you well know, mac paths contain leading colon, this code
messes things up.... */
#else
/* A leading colon means "implementation defined syntax".
We ignore the colon and always use the same algorithm:
try a data file, and if none exists parse the 1003.1 syntax. */
if (tz && *tz == ':')
++tz;
#endif
/* Check whether the value changes since the last run. */
if (old_fgtz != NULL && tz != NULL && strcmp (tz, old_fgtz) == 0)
/* No change, simply return. */
return;
fgtz_rules[0].name = NULL;
fgtz_rules[1].name = NULL;
/* Save the value of `tz'. */
if (old_fgtz != NULL)
free (old_fgtz);
old_fgtz = tz ? strdup (tz) : NULL;
/* Try to read a data file. */
fgtzfile_read (tz);
if (use_fgtzfile)
return;
// The default behaviour of the originale tzset_internal (int always, char* tz)
// function is to set up a default timezone, in any casetz file_read() fails
// Currently this leads to problems, because it modidifies the system timezone
// and not the local aircraft timezone, contained in FlightGear. I could adapt
// this in future versions of this code, but doubt whether this is what we really
// want. So right now, exit when timezone information reading failed.
// Guess I'll change that to something like 12 * (FG_LON / 180.0)
//
// For now, I'll leave it like this.
else
{
printf ("Timezone reading failed\n");
exit(1);
}
// this emacs "comment out" function is cool!
// // /* No data file found. Default to UTC if nothing specified. */
// // printf ("1. Current local time = %24s", asctime(localtime(&now)));
// if (tz == NULL || *tz == '\0')
// {
// fgtz_rules[0].name = fgtz_rules[1].name = "UTC";
// fgtz_rules[0].type = fgtz_rules[1].type = fgtz_rule::J0;
// fgtz_rules[0].m = fgtz_rules[0].n = fgtz_rules[0].d = 0;
// fgtz_rules[1].m = fgtz_rules[1].n = fgtz_rules[1].d = 0;
// fgtz_rules[0].secs = fgtz_rules[1].secs = 0;
// fgtz_rules[0].offset = fgtz_rules[1].offset = 0L;
// fgtz_rules[0].change = fgtz_rules[1].change = (time_t) -1;
// fgtz_rules[0].computed_for = fgtz_rules[1].computed_for = 0;
// return;
// }
// /* Clear out old state and reset to unnamed UTC. */
// //printf ("2. Current local time = %24s", asctime(localtime(&now)));
// memset (fgtz_rules, 0, sizeof fgtz_rules);
// fgtz_rules[0].name = fgtz_rules[1].name = "";
// /* Get the standard timezone name. */
// tzbuf = malloc (strlen (tz) + 1);
// if (! tzbuf)
// {
// /* Clear the old tz name so we will try again. */
// free (old_fgtz);
// old_fgtz = NULL;
// return;
// }
// //printf ("3. Current local time = %24s", asctime(localtime(&now)));
// if (sscanf (tz, "%[^0-9,+-]", tzbuf) != 1 ||
// (l = strlen (tzbuf)) < 3)
// {
// free (tzbuf);
// return;
// }
// fgtz_rules[0].name = tzstring (tzbuf);
// tz += l;
// //printf ("4. Current local time = %24s", asctime(localtime(&now)));
// /* Figure out the standard offset from UTC. */
// if (*tz == '\0' || (*tz != '+' && *tz != '-' && !isdigit (*tz)))
// {
// free (tzbuf);
// return;
// }
// //printf ("5. Current local time = %24s", asctime(localtime(&now)));
// if (*tz == '-' || *tz == '+')
// fgtz_rules[0].offset = *tz++ == '-' ? 1L : -1L;
// else
// fgtz_rules[0].offset = -1L;
// switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
// {
// default:
// free (tzbuf);
// return;
// case 1:
// mm = 0;
// case 2:
// ss = 0;
// case 3:
// break;
// }
// //printf ("6. Current local time = %24s", asctime(localtime(&now)));
// fgtz_rules[0].offset *= (min (ss, 59) + (min (mm, 59) * 60) +
// (min (hh, 23) * 60 * 60));
// for (l = 0; l < 3; ++l)
// {
// while (isdigit(*tz))
// ++tz;
// if (l < 2 && *tz == ':')
// ++tz;
// }
// //printf ("7. Current local time = %24s", asctime(localtime(&now)));
// /* Get the DST timezone name (if any). */
// if (*tz != '\0')
// {
// char *n = tzbuf + strlen (tzbuf) + 1;
// if (sscanf (tz, "%[^0-9,+-]", n) != 1 ||
// (l = strlen (n)) < 3)
// goto done_names; /* Punt on name, set up the offsets. */
// //printf ("7.1 Current local time = %24s", asctime(localtime(&now)));
// fgtz_rules[1].name = tzstring (n);
// tz += l;
// /* Figure out the DST offset from GMT. */
// if (*tz == '-' || *tz == '+')
// fgtz_rules[1].offset = *tz++ == '-' ? 1L : -1L;
// else
// fgtz_rules[1].offset = -1L;
// //printf ("7.2 Current local time = %24s", asctime(localtime(&now)));
// switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
// {
// default:
// /* Default to one hour later than standard time. */
// fgtz_rules[1].offset = fgtz_rules[0].offset + (60 * 60);
// break;
// case 1:
// mm = 0;
// case 2:
// ss = 0;
// case 3:
// fgtz_rules[1].offset *= (min (ss, 59) + (min (mm, 59) * 60) +
// (min (hh, 23) * (60 * 60)));
// break;
// }
// //printf ("7.3 Current local time = %24s", asctime(localtime(&now)));
// for (l = 0; l < 3; ++l)
// {
// while (isdigit (*tz))
// ++tz;
// if (l < 2 && *tz == ':')
// ++tz;
// }
// //printf ("7.4 Current local time = %24s", asctime(localtime(&now)));
// if (*tz == '\0' || (tz[0] == ',' && tz[1] == '\0'))
// {
// /* There is no rule. See if there is a default rule file. */
// //printf ("7.4.1 Current local time = %24s", asctime(localtime(&now)));
// tzfile_default (fgtz_rules[0].name, fgtz_rules[1].name,
// fgtz_rules[0].offset, fgtz_rules[1].offset);
// //printf ("7.4.2 Current local time = %24s", asctime(localtime(&now)));
// if (use_fgtzfile)
// {
// free (old_fgtz);
// old_fgtz = NULL;
// free (tzbuf);
// return;
// }
// }
// }
// else
// {
// /* There is no DST. */
// fgtz_rules[1].name = fgtz_rules[0].name;
// free (tzbuf);
// return;
// }
// //printf ("7.5 Current local time = %24s", asctime(localtime(&now)));
// done_names:
// //printf ("8. Current local time = %24s", asctime(localtime(&now)));
// free (tzbuf);
// /* Figure out the standard <-> DST rules. */
// for (whichrule = 0; whichrule < 2; ++whichrule)
// {
// register fgtz_rule *tzr = &fgtz_rules[whichrule];
// /* Ignore comma to support string following the incorrect
// specification in early POSIX.1 printings. */
// tz += *tz == ',';
// /* Get the date of the change. */
// if (*tz == 'J' || isdigit (*tz))
// {
// char *end;
// tzr->type = *tz == 'J' ? fgtz_rule::J1 : fgtz_rule::J0;
// if (tzr->type == fgtz_rule::J1 && !isdigit (*++tz))
// return;
// tzr->d = (unsigned short int) strtoul (tz, &end, 10);
// if (end == tz || tzr->d > 365)
// return;
// else if (tzr->type == fgtz_rule::J1 && tzr->d == 0)
// return;
// tz = end;
// }
// else if (*tz == 'M')
// {
// int n;
// tzr->type = fgtz_rule::M;
// if (sscanf (tz, "M%hu.%hu.%hu%n",
// &tzr->m, &tzr->n, &tzr->d, &n) != 3 ||
// tzr->m < 1 || tzr->m > 12 ||
// tzr->n < 1 || tzr->n > 5 || tzr->d > 6)
// return;
// tz += n;
// }
// else if (*tz == '\0')
// {
// /* United States Federal Law, the equivalent of "M4.1.0,M10.5.0". */
// tzr->type = fgtz_rule::M;
// if (tzr == &fgtz_rules[0])
// {
// tzr->m = 4;
// tzr->n = 1;
// tzr->d = 0;
// }
// else
// {
// tzr->m = 10;
// tzr->n = 5;
// tzr->d = 0;
// }
// }
// else
// return;
// //printf ("9. Current local time = %24s", asctime(localtime(&now)));
// if (*tz != '\0' && *tz != '/' && *tz != ',')
// return;
// else if (*tz == '/')
// {
// /* Get the time of day of the change. */
// ++tz;
// if (*tz == '\0')
// return;
// switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
// {
// default:
// hh = 2; /* Default to 2:00 AM. */
// case 1:
// mm = 0;
// case 2:
// ss = 0;
// case 3:
// break;
// }
// for (l = 0; l < 3; ++l)
// {
// while (isdigit (*tz))
// ++tz;
// if (l < 2 && *tz == ':')
// ++tz;
// }
// tzr->secs = (hh * 60 * 60) + (mm * 60) + ss;
// }
// else
// /* Default to 2:00 AM. */
// tzr->secs = 2 * 60 * 60;
// tzr->computed_for = -1;
// }
// // printf ("10. Current local time = %24s", asctime(localtime(&now)));
//
}
/************************************************************************/
/* Figure out the correct timezone for *TIMER and TM (which must be the same)
and set `tzname', `timezone', and `daylight' accordingly.
Return nonzero on success, zero on failure. */
size_t fgtzname_cur_max;
static int fgtz_compute (time_t timer, const struct tm* tm)
// time_t timer;
// const struct tm *tm;
{
if (! fgcompute_change (&fgtz_rules[0], 1900 + tm->tm_year) ||
! fgcompute_change (&fgtz_rules[1], 1900 + tm->tm_year))
return 0;
fgdaylight = timer >= fgtz_rules[0].change && timer < fgtz_rules[1].change;
fgtimezone = -fgtz_rules[fgdaylight].offset;
fgtzname[0] = (char *) fgtz_rules[0].name;
fgtzname[1] = (char *) fgtz_rules[1].name;
{
/* Keep tzname_cur_max up to date. */
size_t len0 = strlen (fgtzname[0]);
size_t len1 = strlen (fgtzname[1]);
if (len0 > fgtzname_cur_max)
fgtzname_cur_max = len0;
if (len1 > fgtzname_cur_max)
fgtzname_cur_max = len1;
}
return 1;
}
/**********************************************************************/
/* Figure out the exact time (as a time_t) in YEAR
when the change described by RULE will occur and
put it in RULE->change, saving YEAR in RULE->computed_for.
Return nonzero if successful, zero on failure. */
static int fgcompute_change (fgtz_rule *rule, int year)
// tz_rule *rule;
// int year;
{
register time_t t;
int y;
if (year != -1 && rule->computed_for == year)
/* Operations on times in 1969 will be slower. Oh well. */
return 1;
/* First set T to January 1st, 0:00:00 GMT in YEAR. */
t = 0;
for (y = 1970; y < year; ++y)
t += SECSPERDAY * (isleap (y) ? 366 : 365);
switch (rule->type)
{
case fgtz_rule::J1:
/* Jn - Julian day, 1 == January 1, 60 == March 1 even in leap years.
In non-leap years, or if the day number is 59 or less, just
add SECSPERDAY times the day number-1 to the time of
January 1, midnight, to get the day. */
t += (rule->d - 1) * SECSPERDAY;
if (rule->d >= 60 && isleap (year))
t += SECSPERDAY;
break;
case fgtz_rule::J0:
/* n - Day of year.
Just add SECSPERDAY times the day number to the time of Jan 1st. */
t += rule->d * SECSPERDAY;
break;
case fgtz_rule::M:
/* Mm.n.d - Nth "Dth day" of month M. */
{
register int i, d, m1, yy0, yy1, yy2, dow;
register const unsigned short int *myday =
&mon_yday[isleap (year)][rule->m];
/* First add SECSPERDAY for each day in months before M. */
t += myday[-1] * SECSPERDAY;
/* Use Zeller's Congruence to get day-of-week of first day of month. */
m1 = (rule->m + 9) % 12 + 1;
yy0 = (rule->m <= 2) ? (year - 1) : year;
yy1 = yy0 / 100;
yy2 = yy0 % 100;
dow = ((26 * m1 - 2) / 10 + 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
if (dow < 0)
dow += 7;
/* DOW is the day-of-week of the first day of the month. Get the
day-of-month (zero-origin) of the first DOW day of the month. */
d = rule->d - dow;
if (d < 0)
d += 7;
for (i = 1; i < rule->n; ++i)
{
if (d + 7 >= myday[0] - myday[-1])
break;
d += 7;
}
/* D is the day-of-month (zero-origin) of the day we want. */
t += d * SECSPERDAY;
}
break;
}
/* T is now the Epoch-relative time of 0:00:00 GMT on the day we want.
Just add the time of day and local offset from GMT, and we're done. */
rule->change = t - rule->offset + rule->secs;
rule->computed_for = year;
return 1;
}
/*************************************************************************/
int fgtzfile_compute (time_t timer, int use_localtime,
long int *leap_correct, int *leap_hit)
{
register size_t i;
if (use_localtime)
{
struct ttinfo *info = fgfind_transition (timer);
fgdaylight = info->isdst;
fgtimezone = -info->offset;
for (i = 0;
i < num_types && i < sizeof (fgtzname) / sizeof (fgtzname[0]);
++i)
fgtzname[types[i].isdst] = &zone_names[types[i].idx];
if (info->isdst < sizeof (fgtzname) / sizeof (fgtzname[0]))
fgtzname[info->isdst] = &zone_names[info->idx];
}
*leap_correct = 0L;
*leap_hit = 0;
/* Find the last leap second correction transition time before TIMER. */
i = num_leaps;
do
if (i-- == 0)
return 1;
while (timer < leaps[i].transition);
/* Apply its correction. */
*leap_correct = leaps[i].change;
if (timer == leaps[i].transition && /* Exactly at the transition time. */
((i == 0 && leaps[i].change > 0) ||
leaps[i].change > leaps[i - 1].change))
{
*leap_hit = 1;
while (i > 0 &&
leaps[i].transition == leaps[i - 1].transition + 1 &&
leaps[i].change == leaps[i - 1].change + 1)
{
++*leap_hit;
--i;
}
}
return 1;
}
/**************************************************************************/
static struct ttinfo * fgfind_transition (time_t timer)
{
size_t i;
if (num_transitions == 0 || timer < transitions[0])
{
/* TIMER is before any transition (or there are no transitions).
Choose the first non-DST type
(or the first if they're all DST types). */
i = 0;
while (i < num_types && types[i].isdst)
++i;
if (i == num_types)
i = 0;
}
else
{
/* Find the first transition after TIMER, and
then pick the type of the transition before it. */
for (i = 1; i < num_transitions; ++i)
if (timer < transitions[i])
break;
i = type_idxs[i - 1];
}
return &types[i];
}
/**************************************************************************/
void fgtzfile_read (const char *file)
{
static const char default_tzdir[] = TZDIR;
size_t num_isstd, num_isgmt;
register FILE *f;
struct tzhead tzhead;
size_t chars;
register size_t i;
struct ttinfo *info;
use_fgtzfile = 0;
if (transitions != NULL)
free ((void *) transitions);
transitions = NULL;
if (type_idxs != NULL)
free ((void *) type_idxs);
type_idxs = NULL;
if (types != NULL)
free ((void *) types);
types = NULL;
if (zone_names != NULL)
free ((void *) zone_names);
zone_names = NULL;
if (leaps != NULL)
free ((void *) leaps);
leaps = NULL;
if (file == NULL)
/* No user specification; use the site-wide default. */
file = TZDEFAULT;
else if (*file == '\0')
/* User specified the empty string; use UTC with no leap seconds. */
return;
else
{
/* We must not allow to read an arbitrary file in a setuid
program. So we fail for any file which is not in the
directory hierachy starting at TZDIR
and which is not the system wide default TZDEFAULT. */
//if (libc_enable_secure
// && ((*file == '/'
// && memcmp (file, TZDEFAULT, sizeof TZDEFAULT)
// && memcmp (file, default_tzdir, sizeof (default_tzdir) - 1))
// || strstr (file, "../") != NULL))
/* This test is certainly a bit too restrictive but it should
catch all critical cases. */
//return;
}
// if (*file != '/') // if a relative path is used, append what file points to
// // to the path indicated by TZDIR.
// {
// const char *tzdir;
// unsigned int len, tzdir_len;
// char *_new;
// tzdir = getenv ("TZDIR");
// if (tzdir == NULL || *tzdir == '\0')
// {
// tzdir = default_tzdir;
// tzdir_len = sizeof (default_tzdir) - 1;
// }
// else
// tzdir_len = strlen (tzdir);
// len = strlen (file) + 1;
// _new = (char *) alloca (tzdir_len + 1 + len);
// memcpy (_new, tzdir, tzdir_len);
// _new[tzdir_len] = '/';
// memcpy (&_new[tzdir_len + 1], file, len);
// file = _new;
// }
f = fopen (file, "rb");
if (f == NULL)
return;
if (fread ((void *) &tzhead, sizeof (tzhead), 1, f) != 1)
goto lose;
num_transitions = (size_t) decode (tzhead.tzh_timecnt);
num_types = (size_t) decode (tzhead.tzh_typecnt);
chars = (size_t) decode (tzhead.tzh_charcnt);
num_leaps = (size_t) decode (tzhead.tzh_leapcnt);
num_isstd = (size_t) decode (tzhead.tzh_ttisstdcnt);
num_isgmt = (size_t) decode (tzhead.tzh_ttisgmtcnt);
if (num_transitions > 0)
{
transitions = (time_t *) malloc (num_transitions * sizeof(time_t));
if (transitions == NULL)
goto lose;
type_idxs = (unsigned char *) malloc (num_transitions);
if (type_idxs == NULL)
goto lose;
}
if (num_types > 0)
{
types = (struct ttinfo *) malloc (num_types * sizeof (struct ttinfo));
if (types == NULL)
goto lose;
}
if (chars > 0)
{
zone_names = (char *) malloc (chars);
if (zone_names == NULL)
goto lose;
}
if (num_leaps > 0)
{
leaps = (struct leap *) malloc (num_leaps * sizeof (struct leap));
if (leaps == NULL)
goto lose;
}
if (sizeof (time_t) < 4)
abort ();
if (fread(transitions, 4, num_transitions, f) != num_transitions ||
fread(type_idxs, 1, num_transitions, f) != num_transitions)
goto lose;
/* Check for bogus indices in the data file, so we can hereafter
safely use type_idxs[T] as indices into `types' and never crash. */
for (i = 0; i < num_transitions; ++i)
if (type_idxs[i] >= num_types)
goto lose;
if (BYTE_ORDER != BIG_ENDIAN || sizeof (time_t) != 4)
{
/* Decode the transition times, stored as 4-byte integers in
network (big-endian) byte order. We work from the end of
the array so as not to clobber the next element to be
processed when sizeof (time_t) > 4. */
i = num_transitions;
while (i-- > 0)
transitions[i] = decode ((char *) transitions + i*4);
}
for (i = 0; i < num_types; ++i)
{
unsigned char x[4];
if (fread (x, 1, 4, f) != 4 ||
fread (&types[i].isdst, 1, 1, f) != 1 ||
fread (&types[i].idx, 1, 1, f) != 1)
goto lose;
if (types[i].idx >= chars) /* Bogus index in data file. */
goto lose;
types[i].offset = (long int) decode (x);
}
if (fread (zone_names, 1, chars, f) != chars)
goto lose;
for (i = 0; i < num_leaps; ++i)
{
unsigned char x[4];
if (fread (x, 1, sizeof (x), f) != sizeof (x))
goto lose;
leaps[i].transition = (time_t) decode (x);
if (fread (x, 1, sizeof (x), f) != sizeof (x))
goto lose;
leaps[i].change = (long int) decode (x);
}
for (i = 0; i < num_isstd; ++i)
{
int c = getc (f);
if (c == EOF)
goto lose;
types[i].isstd = c != 0;
}
while (i < num_types)
types[i++].isstd = 0;
for (i = 0; i < num_isgmt; ++i)
{
int c = getc (f);
if (c == EOF)
goto lose;
types[i].isgmt = c != 0;
}
while (i < num_types)
types[i++].isgmt = 0;
fclose (f);
info = fgfind_transition (0);
for (i = 0; i < num_types && i < sizeof (fgtzname) / sizeof (fgtzname[0]);
++i)
fgtzname[types[i].isdst] = tzstring (&zone_names[types[i].idx]);
if (info->isdst < sizeof (fgtzname) / sizeof (fgtzname[0]))
fgtzname[info->isdst] = tzstring (&zone_names[info->idx]);
fgcompute_tzname_max (chars);
use_fgtzfile = 1;
return;
lose:;
fclose(f);
}
/****************************************************************************/
static void fgcompute_tzname_max (size_t chars)
{
extern size_t tzname_cur_max; /* Defined in tzset.c. */
const char *p;
p = zone_names;
do
{
const char *start = p;
while (*p != '\0')
++p;
if ((size_t) (p - start) > fgtzname_cur_max)
fgtzname_cur_max = p - start;
} while (++p < &zone_names[chars]);
}
/**************************************************************************/
//#include <endian.h>
/* Decode the four bytes at PTR as a signed integer in network byte order. */
static inline int decode (const void *ptr)
{
if ((BYTE_ORDER == BIG_ENDIAN) && sizeof (int) == 4)
return *(const int *) ptr;
else
{
const unsigned char *p = (unsigned char *)ptr;
int result = *p & (1 << (CHAR_BIT - 1)) ? ~0 : 0;
result = (result << 8) | *p++;
result = (result << 8) | *p++;
result = (result << 8) | *p++;
result = (result << 8) | *p++;
return result;
}
}
#define SECS_PER_HOUR (60 * 60)
#define SECS_PER_DAY (SECS_PER_HOUR * 24)
/* Compute the `struct tm' representation of *T,
offset OFFSET seconds east of UTC,
and store year, yday, mon, mday, wday, hour, min, sec into *TP. */
void offtime (const time_t *t, long int offset, struct tm *tp)
// const time_t *t;
// long int offset;
// struct tm *tp;
{
register long int days, rem, y;
register const unsigned short int *ip;
days = *t / SECS_PER_DAY;
rem = *t % SECS_PER_DAY;
rem += offset;
while (rem < 0)
{
rem += SECS_PER_DAY;
--days;
}
while (rem >= SECS_PER_DAY)
{
rem -= SECS_PER_DAY;
++days;
}
tp->tm_hour = rem / SECS_PER_HOUR;
rem %= SECS_PER_HOUR;
tp->tm_min = rem / 60;
tp->tm_sec = rem % 60;
/* January 1, 1970 was a Thursday. */
tp->tm_wday = (4 + days) % 7;
if (tp->tm_wday < 0)
tp->tm_wday += 7;
y = 1970;
#define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400)
while (days < 0 || days >= (isleap (y) ? 366 : 365))
{
/* Guess a corrected year, assuming 365 days per year. */
long int yg = y + days / 365 - (days % 365 < 0);
/* Adjust DAYS and Y to match the guessed year. */
days -= ((yg - y) * 365
+ LEAPS_THRU_END_OF (yg - 1)
- LEAPS_THRU_END_OF (y - 1));
y = yg;
}
tp->tm_year = y - 1900;
tp->tm_yday = days;
ip = mon_yday[isleap(y)];
for (y = 11; days < ip[y]; --y)
continue;
days -= ip[y];
tp->tm_mon = y;
tp->tm_mday = days + 1;
}
/* Allocate a time zone string with given contents.
The string will never be moved or deallocated.
However, its contents may be shared with other such strings. */
char *tzstring (const char* string)
//const char *string;
{
struct tzstring_head *h = &tzstring_list.head;
size_t needed;
char *p;
/* Look through time zone string list for a duplicate of this one. */
for (h = &tzstring_list.head; ; h = h->next)
{
for (p = (char *) (h + 1); p[0] | p[1]; ++p)
if (strcmp (p, string) == 0)
return p;
if (! h->next)
break;
}
/* No duplicate was found. Copy to the end of this buffer if there's room;
otherwise, append a large-enough new buffer to the list and use it. */
++p;
needed = strlen (string) + 2; /* Need 2 trailing '\0's after last string. */
if ((size_t) ((char *) (h + 1) + tzstring_last_buffer_size - p) < needed)
{
size_t buffer_size = tzstring_last_buffer_size;
while ((buffer_size *= 2) < needed)
continue;
if (! (h = h->next = (struct tzstring_head *)malloc (sizeof *h + buffer_size)))
return NULL;
h->next = NULL;
tzstring_last_buffer_size = buffer_size;
p = (char *) (h + 1);
}
return strncpy (p, string, needed);
}
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