opensourcemirror
/
postgresql
mirror of git://git.postgresql.org/git/postgresql.git
1
0
Fork 0
Code Issues Releases Wiki Activity
postgresql/src/timezone/localtime.c

1233 lines
32 KiB
C
Raw Blame History

/*
** This file is in the public domain, so clarified as of
** 1996-06-05 by Arthur David Olson (arthur_david_olson@nih.gov).
*/
/*
** Leap second handling from Bradley White (bww@k.gp.cs.cmu.edu).
** POSIX-style TZ environment variable handling from Guy Harris
** (guy@auspex.com).
*/
#include "postgres.h"
#include <fcntl.h>
#include "pgtz.h"
#include "private.h"
#include "tzfile.h"
#ifndef WILDABBR
/*
** Someone might make incorrect use of a time zone abbreviation:
** 1. They might reference tzname[0] before calling tzset (explicitly
** or implicitly).
** 2. They might reference tzname[1] before calling tzset (explicitly
** or implicitly).
** 3. They might reference tzname[1] after setting to a time zone
** in which Daylight Saving Time is never observed.
** 4. They might reference tzname[0] after setting to a time zone
** in which Standard Time is never observed.
** 5. They might reference tm.TM_ZONE after calling offtime.
** What's best to do in the above cases is open to debate;
** for now, we just set things up so that in any of the five cases
** WILDABBR is used. Another possibility: initialize tzname[0] to the
** string "tzname[0] used before set", and similarly for the other cases.
** And another: initialize tzname[0] to "ERA", with an explanation in the
** manual page of what this "time zone abbreviation" means (doing this so
** that tzname[0] has the "normal" length of three characters).
*/
#define WILDABBR " "
#endif /* !defined WILDABBR */
static char wildabbr[] = "WILDABBR";
static const char gmt[] = "GMT";
/*
** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
** We default to US rules as of 1999-08-17.
** POSIX 1003.1 section 8.1.1 says that the default DST rules are
** implementation dependent; for historical reasons, US rules are a
** common default.
*/
#define TZDEFRULESTRING ",M4.1.0,M10.5.0"
struct ttinfo { /* time type information */
long tt_gmtoff; /* UTC offset in seconds */
int tt_isdst; /* used to set tm_isdst */
int tt_abbrind; /* abbreviation list index */
int tt_ttisstd; /* TRUE if transition is std time */
int tt_ttisgmt; /* TRUE if transition is UTC */
};
struct lsinfo { /* leap second information */
time_t ls_trans; /* transition time */
long ls_corr; /* correction to apply */
};
#define BIGGEST(a, b) (((a) > (b)) ? (a) : (b))
struct state {
int leapcnt;
int timecnt;
int typecnt;
int charcnt;
time_t ats[TZ_MAX_TIMES];
unsigned char types[TZ_MAX_TIMES];
struct ttinfo ttis[TZ_MAX_TYPES];
char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
(2 * (TZ_STRLEN_MAX + 1)))];
struct lsinfo lsis[TZ_MAX_LEAPS];
};
struct rule {
int r_type; /* type of rule--see below */
int r_day; /* day number of rule */
int r_week; /* week number of rule */
int r_mon; /* month number of rule */
long r_time; /* transition time of rule */
};
#define JULIAN_DAY 0 /* Jn - Julian day */
#define DAY_OF_YEAR 1 /* n - day of year */
#define MONTH_NTH_DAY_OF_WEEK 2 /* Mm.n.d - month, week, day of week */
/*
** Prototypes for static functions.
*/
static long detzcode(const char *codep);
static const char *getzname(const char *strp);
static const char *getnum(const char *strp, int *nump, int min, int max);
static const char *getsecs(const char *strp, long *secsp);
static const char *getoffset(const char *strp, long *offsetp);
static const char *getrule(const char *strp, struct rule *rulep);
static void gmtload(struct state *sp);
static void gmtsub(const time_t *timep, long offset, struct pg_tm *tmp);
static void localsub(const time_t *timep, long offset, struct pg_tm *tmp);
static int increment_overflow(int *number, int delta);
static int normalize_overflow(int *tensptr, int *unitsptr, int base);
static time_t time1(struct pg_tm *tmp, void(*funcp)(const time_t *, long, struct pg_tm *), long offset);
static time_t time2(struct pg_tm *tmp, void(*funcp)(const time_t *, long, struct pg_tm *), long offset, int *okayp);
static time_t time2sub(struct pg_tm *tmp, void(*funcp)(const time_t *, long, struct pg_tm *), long offset, int *okayp, int do_norm_secs);
static void timesub(const time_t *timep, long offset, const struct state *sp, struct pg_tm *tmp);
static int tmcomp(const struct pg_tm *atmp, const struct pg_tm *btmp);
static time_t transtime(time_t janfirst, int year, const struct rule *rulep, long offset);
static int tzload(const char *name, struct state *sp);
static int tzparse(const char *name, struct state *sp, int lastditch);
static struct state lclmem;
static struct state gmtmem;
#define lclptr (&lclmem)
#define gmtptr (&gmtmem)
static char lcl_TZname[TZ_STRLEN_MAX + 1];
static int lcl_is_set=0;
static int gmt_is_set=0;
/*
** Section 4.12.3 of X3.159-1989 requires that
** Except for the strftime function, these functions [asctime,
** ctime, gmtime, localtime] return values in one of two static
** objects: a broken-down time structure and an array of char.
** Thanks to Paul Eggert (eggert@twinsun.com) for noting this.
*/
static struct pg_tm tm;
static long detzcode(const char *codep)
{
register long result;
register int i;
result = (codep[0] & 0x80) ? ~0L : 0L;
for (i = 0; i < 4; ++i)
result = (result << 8) | (codep[i] & 0xff);
return result;
}
static int tzload(register const char *name, register struct state *sp)
{
register const char * p;
register int i;
register int fid;
if (name == NULL && (name = TZDEFAULT) == NULL)
return -1;
{
register int doaccess;
char fullname[MAXPGPATH];
if (name[0] == ':')
++name;
doaccess = name[0] == '/';
if (!doaccess) {
p = pg_TZDIR();
if (p == NULL)
return -1;
if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
return -1;
(void) strcpy(fullname, p);
(void) strcat(fullname, "/");
(void) strcat(fullname, name);
/*
** Set doaccess if '.' (as in "../") shows up in name.
*/
if (strchr(name, '.') != NULL)
doaccess = TRUE;
name = fullname;
}
if (doaccess && access(name, R_OK) != 0)
return -1;
if ((fid = open(name, O_RDONLY | PG_BINARY)) == -1)
return -1;
}
{
struct tzhead * tzhp;
union {
struct tzhead tzhead;
char buf[sizeof *sp + sizeof *tzhp];
} u;
int ttisstdcnt;
int ttisgmtcnt;
i = read(fid, u.buf, sizeof u.buf);
if (close(fid) != 0)
return -1;
ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
return -1;
if (i - (p - u.buf) < sp->timecnt * 4 + /* ats */
sp->timecnt + /* types */
sp->typecnt * (4 + 2) + /* ttinfos */
sp->charcnt + /* chars */
sp->leapcnt * (4 + 4) + /* lsinfos */
ttisstdcnt + /* ttisstds */
ttisgmtcnt) /* ttisgmts */
return -1;
for (i = 0; i < sp->timecnt; ++i) {
sp->ats[i] = detzcode(p);
p += 4;
}
for (i = 0; i < sp->timecnt; ++i) {
sp->types[i] = (unsigned char) *p++;
if (sp->types[i] >= sp->typecnt)
return -1;
}
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
ttisp = &sp->ttis[i];
ttisp->tt_gmtoff = detzcode(p);
p += 4;
ttisp->tt_isdst = (unsigned char) *p++;
if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
return -1;
ttisp->tt_abbrind = (unsigned char) *p++;
if (ttisp->tt_abbrind < 0 ||
ttisp->tt_abbrind > sp->charcnt)
return -1;
}
for (i = 0; i < sp->charcnt; ++i)
sp->chars[i] = *p++;
sp->chars[i] = '\0'; /* ensure '\0' at end */
for (i = 0; i < sp->leapcnt; ++i) {
register struct lsinfo * lsisp;
lsisp = &sp->lsis[i];
lsisp->ls_trans = detzcode(p);
p += 4;
lsisp->ls_corr = detzcode(p);
p += 4;
}
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
ttisp = &sp->ttis[i];
if (ttisstdcnt == 0)
ttisp->tt_ttisstd = FALSE;
else {
ttisp->tt_ttisstd = *p++;
if (ttisp->tt_ttisstd != TRUE &&
ttisp->tt_ttisstd != FALSE)
return -1;
}
}
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
ttisp = &sp->ttis[i];
if (ttisgmtcnt == 0)
ttisp->tt_ttisgmt = FALSE;
else {
ttisp->tt_ttisgmt = *p++;
if (ttisp->tt_ttisgmt != TRUE &&
ttisp->tt_ttisgmt != FALSE)
return -1;
}
}
}
return 0;
}
static const int mon_lengths[2][MONSPERYEAR] = {
{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
};
static const int year_lengths[2] = {
DAYSPERNYEAR, DAYSPERLYEAR
};
/*
** Given a pointer into a time zone string, scan until a character that is not
** a valid character in a zone name is found. Return a pointer to that
** character.
*/
static const char *getzname(register const char *strp)
{
register char c;
while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
c != '+')
++strp;
return strp;
}
/*
** Given a pointer into a time zone string, extract a number from that string.
** Check that the number is within a specified range; if it is not, return
** NULL.
** Otherwise, return a pointer to the first character not part of the number.
*/
static const char *getnum(register const char *strp, int *nump, const int min, const int max)
{
register char c;
register int num;
if (strp == NULL || !is_digit(c = *strp))
return NULL;
num = 0;
do {
num = num * 10 + (c - '0');
if (num > max)
return NULL; /* illegal value */
c = *++strp;
} while (is_digit(c));
if (num < min)
return NULL; /* illegal value */
*nump = num;
return strp;
}
/*
** Given a pointer into a time zone string, extract a number of seconds,
** in hh[:mm[:ss]] form, from the string.
** If any error occurs, return NULL.
** Otherwise, return a pointer to the first character not part of the number
** of seconds.
*/
static const char *getsecs(register const char *strp, long *secsp)
{
int num;
/*
** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
** "M10.4.6/26", which does not conform to Posix,
** but which specifies the equivalent of
** ``02:00 on the first Sunday on or after 23 Oct''.
*/
strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
if (strp == NULL)
return NULL;
*secsp = num * (long) SECSPERHOUR;
if (*strp == ':') {
++strp;
strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
if (strp == NULL)
return NULL;
*secsp += num * SECSPERMIN;
if (*strp == ':') {
++strp;
/* `SECSPERMIN' allows for leap seconds. */
strp = getnum(strp, &num, 0, SECSPERMIN);
if (strp == NULL)
return NULL;
*secsp += num;
}
}
return strp;
}
/*
** Given a pointer into a time zone string, extract an offset, in
** [+-]hh[:mm[:ss]] form, from the string.
** If any error occurs, return NULL.
** Otherwise, return a pointer to the first character not part of the time.
*/
static const char *getoffset(register const char *strp, long *offsetp)
{
register int neg = 0;
if (*strp == '-') {
neg = 1;
++strp;
} else if (*strp == '+')
++strp;
strp = getsecs(strp, offsetp);
if (strp == NULL)
return NULL; /* illegal time */
if (neg)
*offsetp = -*offsetp;
return strp;
}
/*
** Given a pointer into a time zone string, extract a rule in the form
** date[/time]. See POSIX section 8 for the format of "date" and "time".
** If a valid rule is not found, return NULL.
** Otherwise, return a pointer to the first character not part of the rule.
*/
static const char *getrule(const char *strp, register struct rule *rulep)
{
if (*strp == 'J') {
/*
** Julian day.
*/
rulep->r_type = JULIAN_DAY;
++strp;
strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
} else if (*strp == 'M') {
/*
** Month, week, day.
*/
rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
++strp;
strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
if (strp == NULL)
return NULL;
if (*strp++ != '.')
return NULL;
strp = getnum(strp, &rulep->r_week, 1, 5);
if (strp == NULL)
return NULL;
if (*strp++ != '.')
return NULL;
strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
} else if (is_digit(*strp)) {
/*
** Day of year.
*/
rulep->r_type = DAY_OF_YEAR;
strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
} else return NULL; /* invalid format */
if (strp == NULL)
return NULL;
if (*strp == '/') {
/*
** Time specified.
*/
++strp;
strp = getsecs(strp, &rulep->r_time);
} else rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
return strp;
}
/*
** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
** year, a rule, and the offset from UTC at the time that rule takes effect,
** calculate the Epoch-relative time that rule takes effect.
*/
static time_t transtime(const time_t janfirst, const int year, register const struct rule *rulep, const long offset)
{
register int leapyear;
register time_t value = 0;
register int i;
int d, m1, yy0, yy1, yy2, dow;
leapyear = isleap(year);
switch (rulep->r_type) {
case JULIAN_DAY:
/*
** 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.
*/
value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
if (leapyear && rulep->r_day >= 60)
value += SECSPERDAY;
break;
case DAY_OF_YEAR:
/*
** n - day of year.
** Just add SECSPERDAY times the day number to the time of
** January 1, midnight, to get the day.
*/
value = janfirst + rulep->r_day * SECSPERDAY;
break;
case MONTH_NTH_DAY_OF_WEEK:
/*
** Mm.n.d - nth "dth day" of month m.
*/
value = janfirst;
for (i = 0; i < rulep->r_mon - 1; ++i)
value += mon_lengths[leapyear][i] * SECSPERDAY;
/*
** Use Zeller's Congruence to get day-of-week of first day of
** month.
*/
m1 = (rulep->r_mon + 9) % 12 + 1;
yy0 = (rulep->r_mon <= 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 += DAYSPERWEEK;
/*
** "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 = rulep->r_day - dow;
if (d < 0)
d += DAYSPERWEEK;
for (i = 1; i < rulep->r_week; ++i) {
if (d + DAYSPERWEEK >=
mon_lengths[leapyear][rulep->r_mon - 1])
break;
d += DAYSPERWEEK;
}
/*
** "d" is the day-of-month (zero-origin) of the day we want.
*/
value += d * SECSPERDAY;
break;
}
/*
** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
** question. To get the Epoch-relative time of the specified local
** time on that day, add the transition time and the current offset
** from UTC.
*/
return value + rulep->r_time + offset;
}
/*
** Given a POSIX section 8-style TZ string, fill in the rule tables as
** appropriate.
*/
static int tzparse(const char *name, register struct state *sp, const int lastditch)
{
const char * stdname;
const char * dstname = NULL;
size_t stdlen;
size_t dstlen;
long stdoffset;
long dstoffset;
register time_t * atp;
register unsigned char * typep;
register char * cp;
register int load_result;
stdname = name;
if (lastditch) {
stdlen = strlen(name); /* length of standard zone name */
name += stdlen;
if (stdlen >= sizeof sp->chars)
stdlen = (sizeof sp->chars) - 1;
stdoffset = 0;
} else {
name = getzname(name);
stdlen = name - stdname;
if (stdlen < 3)
return -1;
if (*name == '\0')
return -1;
name = getoffset(name, &stdoffset);
if (name == NULL)
return -1;
}
load_result = tzload(TZDEFRULES, sp);
if (load_result != 0)
sp->leapcnt = 0; /* so, we're off a little */
if (*name != '\0') {
dstname = name;
name = getzname(name);
dstlen = name - dstname; /* length of DST zone name */
if (dstlen < 3)
return -1;
if (*name != '\0' && *name != ',' && *name != ';') {
name = getoffset(name, &dstoffset);
if (name == NULL)
return -1;
} else dstoffset = stdoffset - SECSPERHOUR;
if (*name == '\0' && load_result != 0)
name = TZDEFRULESTRING;
if (*name == ',' || *name == ';') {
struct rule start;
struct rule end;
register int year;
register time_t janfirst;
time_t starttime;
time_t endtime;
++name;
if ((name = getrule(name, &start)) == NULL)
return -1;
if (*name++ != ',')
return -1;
if ((name = getrule(name, &end)) == NULL)
return -1;
if (*name != '\0')
return -1;
sp->typecnt = 2; /* standard time and DST */
/*
** Two transitions per year, from EPOCH_YEAR to 2037.
*/
sp->timecnt = 2 * (2037 - EPOCH_YEAR + 1);
if (sp->timecnt > TZ_MAX_TIMES)
return -1;
sp->ttis[0].tt_gmtoff = -dstoffset;
sp->ttis[0].tt_isdst = 1;
sp->ttis[0].tt_abbrind = stdlen + 1;
sp->ttis[1].tt_gmtoff = -stdoffset;
sp->ttis[1].tt_isdst = 0;
sp->ttis[1].tt_abbrind = 0;
atp = sp->ats;
typep = sp->types;
janfirst = 0;
for (year = EPOCH_YEAR; year <= 2037; ++year) {
starttime = transtime(janfirst, year, &start,
stdoffset);
endtime = transtime(janfirst, year, &end,
dstoffset);
if (starttime > endtime) {
*atp++ = endtime;
*typep++ = 1; /* DST ends */
*atp++ = starttime;
*typep++ = 0; /* DST begins */
} else {
*atp++ = starttime;
*typep++ = 0; /* DST begins */
*atp++ = endtime;
*typep++ = 1; /* DST ends */
}
janfirst += year_lengths[isleap(year)] *
SECSPERDAY;
}
} else {
register long theirstdoffset;
register long theirdstoffset;
register long theiroffset;
register int isdst;
register int i;
register int j;
if (*name != '\0')
return -1;
/*
** Initial values of theirstdoffset and theirdstoffset.
*/
theirstdoffset = 0;
for (i = 0; i < sp->timecnt; ++i) {
j = sp->types[i];
if (!sp->ttis[j].tt_isdst) {
theirstdoffset =
-sp->ttis[j].tt_gmtoff;
break;
}
}
theirdstoffset = 0;
for (i = 0; i < sp->timecnt; ++i) {
j = sp->types[i];
if (sp->ttis[j].tt_isdst) {
theirdstoffset =
-sp->ttis[j].tt_gmtoff;
break;
}
}
/*
** Initially we're assumed to be in standard time.
*/
isdst = FALSE;
theiroffset = theirstdoffset;
/*
** Now juggle transition times and types
** tracking offsets as you do.
*/
for (i = 0; i < sp->timecnt; ++i) {
j = sp->types[i];
sp->types[i] = sp->ttis[j].tt_isdst;
if (sp->ttis[j].tt_ttisgmt) {
/* No adjustment to transition time */
} else {
/*
** If summer time is in effect, and the
** transition time was not specified as
** standard time, add the summer time
** offset to the transition time;
** otherwise, add the standard time
** offset to the transition time.
*/
/*
** Transitions from DST to DDST
** will effectively disappear since
** POSIX provides for only one DST
** offset.
*/
if (isdst && !sp->ttis[j].tt_ttisstd) {
sp->ats[i] += dstoffset -
theirdstoffset;
} else {
sp->ats[i] += stdoffset -
theirstdoffset;
}
}
theiroffset = -sp->ttis[j].tt_gmtoff;
if (sp->ttis[j].tt_isdst)
theirdstoffset = theiroffset;
else theirstdoffset = theiroffset;
}
/*
** Finally, fill in ttis.
** ttisstd and ttisgmt need not be handled.
*/
sp->ttis[0].tt_gmtoff = -stdoffset;
sp->ttis[0].tt_isdst = FALSE;
sp->ttis[0].tt_abbrind = 0;
sp->ttis[1].tt_gmtoff = -dstoffset;
sp->ttis[1].tt_isdst = TRUE;
sp->ttis[1].tt_abbrind = stdlen + 1;
sp->typecnt = 2;
}
} else {
dstlen = 0;
sp->typecnt = 1; /* only standard time */
sp->timecnt = 0;
sp->ttis[0].tt_gmtoff = -stdoffset;
sp->ttis[0].tt_isdst = 0;
sp->ttis[0].tt_abbrind = 0;
}
sp->charcnt = stdlen + 1;
if (dstlen != 0)
sp->charcnt += dstlen + 1;
if ((size_t) sp->charcnt > sizeof sp->chars)
return -1;
cp = sp->chars;
(void) strncpy(cp, stdname, stdlen);
cp += stdlen;
*cp++ = '\0';
if (dstlen != 0) {
(void) strncpy(cp, dstname, dstlen);
*(cp + dstlen) = '\0';
}
return 0;
}
static void gmtload(struct state *sp)
{
if (tzload(gmt, sp) != 0)
(void) tzparse(gmt, sp, TRUE);
}
bool pg_tzset(const char *name)
{
if (lcl_is_set && strcmp(lcl_TZname, name) == 0)
return true; /* no change */
if (strlen(name) >= sizeof(lcl_TZname))
return false; /* not gonna fit */
if (tzload(name, lclptr) != 0) {
if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
{
/* Unknown timezone. Fail our call instead of loading GMT! */
return false;
}
}
strcpy(lcl_TZname, name);
lcl_is_set = true;
return true;
}
/*
** The easy way to behave "as if no library function calls" localtime
** is to not call it--so we drop its guts into "localsub", which can be
** freely called. (And no, the PANS doesn't require the above behavior--
** but it *is* desirable.)
**
** The unused offset argument is for the benefit of mktime variants.
*/
static void localsub(const time_t *timep, const long offset, struct pg_tm *tmp)
{
register struct state * sp;
register const struct ttinfo * ttisp;
register int i;
const time_t t = *timep;
sp = lclptr;
if (sp->timecnt == 0 || t < sp->ats[0]) {
i = 0;
while (sp->ttis[i].tt_isdst)
if (++i >= sp->typecnt) {
i = 0;
break;
}
} else {
for (i = 1; i < sp->timecnt; ++i)
if (t < sp->ats[i])
break;
i = sp->types[i - 1];
}
ttisp = &sp->ttis[i];
/*
** To get (wrong) behavior that's compatible with System V Release 2.0
** you'd replace the statement below with
** t += ttisp->tt_gmtoff;
** timesub(&t, 0L, sp, tmp);
*/
timesub(&t, ttisp->tt_gmtoff, sp, tmp);
tmp->tm_isdst = ttisp->tt_isdst;
tmp->tm_zone = &sp->chars[ttisp->tt_abbrind];
}
struct pg_tm *pg_localtime(const time_t *timep)
{
localsub(timep, 0L, &tm);
return &tm;
}
/*
** gmtsub is to gmtime as localsub is to localtime.
*/
static void gmtsub(const time_t *timep, const long offset, struct pg_tm *tmp)
{
if (!gmt_is_set) {
gmt_is_set = TRUE;
gmtload(gmtptr);
}
timesub(timep, offset, gmtptr, tmp);
/*
** Could get fancy here and deliver something such as
** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
** but this is no time for a treasure hunt.
*/
if (offset != 0)
tmp->tm_zone = wildabbr;
else {
tmp->tm_zone = gmtptr->chars;
}
}
struct pg_tm *pg_gmtime(const time_t *timep)
{
gmtsub(timep, 0L, &tm);
return &tm;
}
static void timesub(const time_t *timep, const long offset, register const struct state *sp, register struct pg_tm *tmp)
{
register const struct lsinfo * lp;
register long days;
register long rem;
register int y;
register int yleap;
register const int * ip;
register long corr;
register int hit;
register int i;
corr = 0;
hit = 0;
i = sp->leapcnt;
while (--i >= 0) {
lp = &sp->lsis[i];
if (*timep >= lp->ls_trans) {
if (*timep == lp->ls_trans) {
hit = ((i == 0 && lp->ls_corr > 0) ||
lp->ls_corr > sp->lsis[i - 1].ls_corr);
if (hit)
while (i > 0 &&
sp->lsis[i].ls_trans ==
sp->lsis[i - 1].ls_trans + 1 &&
sp->lsis[i].ls_corr ==
sp->lsis[i - 1].ls_corr + 1) {
++hit;
--i;
}
}
corr = lp->ls_corr;
break;
}
}
days = *timep / SECSPERDAY;
rem = *timep % SECSPERDAY;
#ifdef mc68k
if (*timep == 0x80000000) {
/*
** A 3B1 muffs the division on the most negative number.
*/
days = -24855;
rem = -11648;
}
#endif /* defined mc68k */
rem += (offset - corr);
while (rem < 0) {
rem += SECSPERDAY;
--days;
}
while (rem >= SECSPERDAY) {
rem -= SECSPERDAY;
++days;
}
tmp->tm_hour = (int) (rem / SECSPERHOUR);
rem = rem % SECSPERHOUR;
tmp->tm_min = (int) (rem / SECSPERMIN);
/*
** A positive leap second requires a special
** representation. This uses "... ??:59:60" et seq.
*/
tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
tmp->tm_wday = (int) ((EPOCH_WDAY + days) % DAYSPERWEEK);
if (tmp->tm_wday < 0)
tmp->tm_wday += DAYSPERWEEK;
y = EPOCH_YEAR;
#define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400)
while (days < 0 || days >= (long) year_lengths[yleap = isleap(y)]) {
register int newy;
newy = y + days / DAYSPERNYEAR;
if (days < 0)
--newy;
days -= (newy - y) * DAYSPERNYEAR +
LEAPS_THRU_END_OF(newy - 1) -
LEAPS_THRU_END_OF(y - 1);
y = newy;
}
tmp->tm_year = y - TM_YEAR_BASE;
tmp->tm_yday = (int) days;
ip = mon_lengths[yleap];
for (tmp->tm_mon = 0; days >= (long) ip[tmp->tm_mon]; ++(tmp->tm_mon))
days = days - (long) ip[tmp->tm_mon];
tmp->tm_mday = (int) (days + 1);
tmp->tm_isdst = 0;
tmp->tm_gmtoff = offset;
}
/*
** Adapted from code provided by Robert Elz, who writes:
** The "best" way to do mktime I think is based on an idea of Bob
** Kridle's (so its said...) from a long time ago.
** [kridle@xinet.com as of 1996-01-16.]
** It does a binary search of the time_t space. Since time_t's are
** just 32 bits, its a max of 32 iterations (even at 64 bits it
** would still be very reasonable).
*/
#define WRONG (-1)
/*
** Simplified normalize logic courtesy Paul Eggert (eggert@twinsun.com).
*/
static int increment_overflow(int *number, int delta)
{
int number0;
number0 = *number;
*number += delta;
return (*number < number0) != (delta < 0);
}
static int normalize_overflow(int *tensptr, int *unitsptr, const int base)
{
register int tensdelta;
tensdelta = (*unitsptr >= 0) ?
(*unitsptr / base) :
(-1 - (-1 - *unitsptr) / base);
*unitsptr -= tensdelta * base;
return increment_overflow(tensptr, tensdelta);
}
static int tmcomp(register const struct pg_tm *atmp, register const struct pg_tm *btmp)
{
register int result;
if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
(result = (atmp->tm_min - btmp->tm_min)) == 0)
result = atmp->tm_sec - btmp->tm_sec;
return result;
}
static time_t time2sub(struct pg_tm *tmp, void(*funcp)(const time_t *, long, struct pg_tm *), const long offset, int *okayp, const int do_norm_secs)
{
register const struct state * sp;
register int dir;
register int bits;
register int i, j ;
register int saved_seconds;
time_t newt;
time_t t;
struct pg_tm yourtm, mytm;
*okayp = FALSE;
yourtm = *tmp;
if (do_norm_secs) {
if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
SECSPERMIN))
return WRONG;
}
if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
return WRONG;
if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
return WRONG;
if (normalize_overflow(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR))
return WRONG;
/*
** Turn yourtm.tm_year into an actual year number for now.
** It is converted back to an offset from TM_YEAR_BASE later.
*/
if (increment_overflow(&yourtm.tm_year, TM_YEAR_BASE))
return WRONG;
while (yourtm.tm_mday <= 0) {
if (increment_overflow(&yourtm.tm_year, -1))
return WRONG;
i = yourtm.tm_year + (1 < yourtm.tm_mon);
yourtm.tm_mday += year_lengths[isleap(i)];
}
while (yourtm.tm_mday > DAYSPERLYEAR) {
i = yourtm.tm_year + (1 < yourtm.tm_mon);
yourtm.tm_mday -= year_lengths[isleap(i)];
if (increment_overflow(&yourtm.tm_year, 1))
return WRONG;
}
for ( ; ; ) {
i = mon_lengths[isleap(yourtm.tm_year)][yourtm.tm_mon];
if (yourtm.tm_mday <= i)
break;
yourtm.tm_mday -= i;
if (++yourtm.tm_mon >= MONSPERYEAR) {
yourtm.tm_mon = 0;
if (increment_overflow(&yourtm.tm_year, 1))
return WRONG;
}
}
if (increment_overflow(&yourtm.tm_year, -TM_YEAR_BASE))
return WRONG;
if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
saved_seconds = 0;
else if (yourtm.tm_year + TM_YEAR_BASE < EPOCH_YEAR) {
/*
** We can't set tm_sec to 0, because that might push the
** time below the minimum representable time.
** Set tm_sec to 59 instead.
** This assumes that the minimum representable time is
** not in the same minute that a leap second was deleted from,
** which is a safer assumption than using 58 would be.
*/
if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
return WRONG;
saved_seconds = yourtm.tm_sec;
yourtm.tm_sec = SECSPERMIN - 1;
} else {
saved_seconds = yourtm.tm_sec;
yourtm.tm_sec = 0;
}
/*
** Divide the search space in half
** (this works whether time_t is signed or unsigned).
*/
bits = TYPE_BIT(time_t) - 1;
/*
** If time_t is signed, then 0 is just above the median,
** assuming two's complement arithmetic.
** If time_t is unsigned, then (1 << bits) is just above the median.
*/
t = TYPE_SIGNED(time_t) ? 0 : (((time_t) 1) << bits);
for ( ; ; ) {
(*funcp)(&t, offset, &mytm);
dir = tmcomp(&mytm, &yourtm);
if (dir != 0) {
if (bits-- < 0)
return WRONG;
if (bits < 0)
--t; /* may be needed if new t is minimal */
else if (dir > 0)
t -= ((time_t) 1) << bits;
else t += ((time_t) 1) << bits;
continue;
}
if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
break;
/*
** Right time, wrong type.
** Hunt for right time, right type.
** It's okay to guess wrong since the guess
** gets checked.
*/
/*
** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
*/
sp = (const struct state *)
(((void *) funcp == (void *) localsub) ?
lclptr : gmtptr);
for (i = sp->typecnt - 1; i >= 0; --i) {
if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
continue;
for (j = sp->typecnt - 1; j >= 0; --j) {
if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
continue;
newt = t + sp->ttis[j].tt_gmtoff -
sp->ttis[i].tt_gmtoff;
(*funcp)(&newt, offset, &mytm);
if (tmcomp(&mytm, &yourtm) != 0)
continue;
if (mytm.tm_isdst != yourtm.tm_isdst)
continue;
/*
** We have a match.
*/
t = newt;
goto label;
}
}
return WRONG;
}
label:
newt = t + saved_seconds;
if ((newt < t) != (saved_seconds < 0))
return WRONG;
t = newt;
(*funcp)(&t, offset, tmp);
*okayp = TRUE;
return t;
}
static time_t time2(struct pg_tm *tmp, void(*funcp)(const time_t*, long, struct pg_tm*), const long offset, int *okayp)
{
time_t t;
/*
** First try without normalization of seconds
** (in case tm_sec contains a value associated with a leap second).
** If that fails, try with normalization of seconds.
*/
t = time2sub(tmp, funcp, offset, okayp, FALSE);
return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
}
static time_t time1(struct pg_tm *tmp, void (*funcp)(const time_t *, long, struct pg_tm *), const long offset)
{
register time_t t;
register const struct state * sp;
register int samei, otheri;
register int sameind, otherind;
register int i;
register int nseen;
int seen[TZ_MAX_TYPES];
int types[TZ_MAX_TYPES];
int okay;
if (tmp->tm_isdst > 1)
tmp->tm_isdst = 1;
t = time2(tmp, funcp, offset, &okay);
if (okay || tmp->tm_isdst < 0)
return t;
/*
** We're supposed to assume that somebody took a time of one type
** and did some math on it that yielded a "struct pg_tm" that's bad.
** We try to divine the type they started from and adjust to the
** type they need.
*/
/*
** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
*/
sp = (const struct state *) (((void *) funcp == (void *) localsub) ?
lclptr : gmtptr);
for (i = 0; i < sp->typecnt; ++i)
seen[i] = FALSE;
nseen = 0;
for (i = sp->timecnt - 1; i >= 0; --i)
if (!seen[sp->types[i]]) {
seen[sp->types[i]] = TRUE;
types[nseen++] = sp->types[i];
}
for (sameind = 0; sameind < nseen; ++sameind) {
samei = types[sameind];
if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
continue;
for (otherind = 0; otherind < nseen; ++otherind) {
otheri = types[otherind];
if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
continue;
tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
sp->ttis[samei].tt_gmtoff;
tmp->tm_isdst = !tmp->tm_isdst;
t = time2(tmp, funcp, offset, &okay);
if (okay)
return t;
tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
sp->ttis[samei].tt_gmtoff;
tmp->tm_isdst = !tmp->tm_isdst;
}
}
return WRONG;
}
time_t pg_mktime(struct pg_tm *tmp)
{
return time1(tmp, localsub, 0L);
}
/*
* Return the name of the current timezone
*/
const char *
pg_get_current_timezone(void) {
if (lcl_is_set)
return lcl_TZname;
return NULL;
}
Reference in New Issue View Git Blame Copy Permalink