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localtime.c
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localtime.c
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/* Convert timestamp from time_t to struct tm. */
/*
** This file is in the public domain, so clarified as of
** 1996-06-05 by Arthur David Olson.
*/
/*
** Leap second handling from Bradley White.
** POSIX-style TZ environment variable handling from Guy Harris.
*/
/*LINTLIBRARY*/
#define LOCALTIME_IMPLEMENTATION
#include "private.h"
#include "tzfile.h"
#include <fcntl.h>
#if defined THREAD_SAFE && THREAD_SAFE
# include <pthread.h>
static pthread_mutex_t locallock = PTHREAD_MUTEX_INITIALIZER;
static int lock(void) { return pthread_mutex_lock(&locallock); }
static void unlock(void) { pthread_mutex_unlock(&locallock); }
#else
static int lock(void) { return 0; }
static void unlock(void) { }
#endif
/* NETBSD_INSPIRED_EXTERN functions are exported to callers if
NETBSD_INSPIRED is defined, and are private otherwise. */
#if NETBSD_INSPIRED
# define NETBSD_INSPIRED_EXTERN
#else
# define NETBSD_INSPIRED_EXTERN static
#endif
#ifndef TZ_ABBR_MAX_LEN
#define TZ_ABBR_MAX_LEN 16
#endif /* !defined TZ_ABBR_MAX_LEN */
#ifndef TZ_ABBR_CHAR_SET
#define TZ_ABBR_CHAR_SET \
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
#endif /* !defined TZ_ABBR_CHAR_SET */
#ifndef TZ_ABBR_ERR_CHAR
#define TZ_ABBR_ERR_CHAR '_'
#endif /* !defined TZ_ABBR_ERR_CHAR */
/*
** SunOS 4.1.1 headers lack O_BINARY.
*/
#ifdef O_BINARY
#define OPEN_MODE (O_RDONLY | O_BINARY)
#endif /* defined O_BINARY */
#ifndef O_BINARY
#define OPEN_MODE O_RDONLY
#endif /* !defined O_BINARY */
#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 const char wildabbr[] = WILDABBR;
static const char gmt[] = "GMT";
/*
** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
** Default to US rules as of 2017-05-07.
** POSIX does not specify the default DST rules;
** for historical reasons, US rules are a common default.
*/
#ifndef TZDEFRULESTRING
#define TZDEFRULESTRING ",M3.2.0,M11.1.0"
#endif
struct ttinfo { /* time type information */
int_fast32_t tt_utoff; /* UT offset in seconds */
bool tt_isdst; /* used to set tm_isdst */
int tt_desigidx; /* abbreviation list index */
bool tt_ttisstd; /* transition is std time */
bool tt_ttisut; /* transition is UT */
};
struct lsinfo { /* leap second information */
time_t ls_trans; /* transition time */
int_fast64_t ls_corr; /* correction to apply */
};
#define SMALLEST(a, b) (((a) < (b)) ? (a) : (b))
#define BIGGEST(a, b) (((a) > (b)) ? (a) : (b))
#ifdef TZNAME_MAX
#define MY_TZNAME_MAX TZNAME_MAX
#endif /* defined TZNAME_MAX */
#ifndef TZNAME_MAX
#define MY_TZNAME_MAX 255
#endif /* !defined TZNAME_MAX */
struct state {
int leapcnt;
int timecnt;
int typecnt;
int charcnt;
bool goback;
bool goahead;
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 * (MY_TZNAME_MAX + 1)))];
struct lsinfo lsis[TZ_MAX_LEAPS];
/* The time type to use for early times or if no transitions.
It is always zero for recent tzdb releases.
It might be nonzero for data from tzdb 2018e or earlier. */
int defaulttype;
};
enum r_type {
JULIAN_DAY, /* Jn = Julian day */
DAY_OF_YEAR, /* n = day of year */
MONTH_NTH_DAY_OF_WEEK /* Mm.n.d = month, week, day of week */
};
struct rule {
enum r_type r_type; /* type of rule */
int r_day; /* day number of rule */
int r_week; /* week number of rule */
int r_mon; /* month number of rule */
int_fast32_t r_time; /* transition time of rule */
};
static struct tm *gmtsub(struct state const *, time_t const *, int_fast32_t,
struct tm *);
static bool increment_overflow(int *, int);
static bool increment_overflow_time(time_t *, int_fast32_t);
static int_fast64_t leapcorr(struct state const *, time_t);
static bool normalize_overflow32(int_fast32_t *, int *, int);
static struct tm *timesub(time_t const *, int_fast32_t, struct state const *,
struct tm *);
static bool typesequiv(struct state const *, int, int);
static bool tzparse(char const *, struct state *, bool);
#ifdef ALL_STATE
static struct state * lclptr;
static struct state * gmtptr;
#endif /* defined ALL_STATE */
#ifndef ALL_STATE
static struct state lclmem;
static struct state gmtmem;
#define lclptr (&lclmem)
#define gmtptr (&gmtmem)
#endif /* State Farm */
#ifndef TZ_STRLEN_MAX
#define TZ_STRLEN_MAX 255
#endif /* !defined TZ_STRLEN_MAX */
static char lcl_TZname[TZ_STRLEN_MAX + 1];
static int lcl_is_set;
/*
** 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 for noting this.
*/
static struct tm tm;
#if 2 <= HAVE_TZNAME + TZ_TIME_T
char * tzname[2] = {
(char *) wildabbr,
(char *) wildabbr
};
#endif
#if 2 <= USG_COMPAT + TZ_TIME_T
long timezone;
int daylight;
#endif
#if 2 <= ALTZONE + TZ_TIME_T
long altzone;
#endif
/* Initialize *S to a value based on UTOFF, ISDST, and DESIGIDX. */
static void
init_ttinfo(struct ttinfo *s, int_fast32_t utoff, bool isdst, int desigidx)
{
s->tt_utoff = utoff;
s->tt_isdst = isdst;
s->tt_desigidx = desigidx;
s->tt_ttisstd = false;
s->tt_ttisut = false;
}
static int_fast32_t
detzcode(const char *const codep)
{
register int_fast32_t result;
register int i;
int_fast32_t one = 1;
int_fast32_t halfmaxval = one << (32 - 2);
int_fast32_t maxval = halfmaxval - 1 + halfmaxval;
int_fast32_t minval = -1 - maxval;
result = codep[0] & 0x7f;
for (i = 1; i < 4; ++i)
result = (result << 8) | (codep[i] & 0xff);
if (codep[0] & 0x80) {
/* Do two's-complement negation even on non-two's-complement machines.
If the result would be minval - 1, return minval. */
result -= !TWOS_COMPLEMENT(int_fast32_t) && result != 0;
result += minval;
}
return result;
}
static int_fast64_t
detzcode64(const char *const codep)
{
register uint_fast64_t result;
register int i;
int_fast64_t one = 1;
int_fast64_t halfmaxval = one << (64 - 2);
int_fast64_t maxval = halfmaxval - 1 + halfmaxval;
int_fast64_t minval = -TWOS_COMPLEMENT(int_fast64_t) - maxval;
result = codep[0] & 0x7f;
for (i = 1; i < 8; ++i)
result = (result << 8) | (codep[i] & 0xff);
if (codep[0] & 0x80) {
/* Do two's-complement negation even on non-two's-complement machines.
If the result would be minval - 1, return minval. */
result -= !TWOS_COMPLEMENT(int_fast64_t) && result != 0;
result += minval;
}
return result;
}
static void
update_tzname_etc(struct state const *sp, struct ttinfo const *ttisp)
{
#if HAVE_TZNAME
tzname[ttisp->tt_isdst] = (char *) &sp->chars[ttisp->tt_desigidx];
#endif
#if USG_COMPAT
if (!ttisp->tt_isdst)
timezone = - ttisp->tt_utoff;
#endif
#if ALTZONE
if (ttisp->tt_isdst)
altzone = - ttisp->tt_utoff;
#endif
}
static void
settzname(void)
{
register struct state * const sp = lclptr;
register int i;
#if HAVE_TZNAME
tzname[0] = tzname[1] = (char *) (sp ? wildabbr : gmt);
#endif
#if USG_COMPAT
daylight = 0;
timezone = 0;
#endif
#if ALTZONE
altzone = 0;
#endif
if (sp == NULL) {
return;
}
/*
** And to get the latest time zone abbreviations into tzname. . .
*/
for (i = 0; i < sp->typecnt; ++i) {
register const struct ttinfo * const ttisp = &sp->ttis[i];
update_tzname_etc(sp, ttisp);
}
for (i = 0; i < sp->timecnt; ++i) {
register const struct ttinfo * const ttisp =
&sp->ttis[
sp->types[i]];
update_tzname_etc(sp, ttisp);
#if USG_COMPAT
if (ttisp->tt_isdst)
daylight = 1;
#endif
}
}
static void
scrub_abbrs(struct state *sp)
{
int i;
/*
** First, replace bogus characters.
*/
for (i = 0; i < sp->charcnt; ++i)
if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
sp->chars[i] = TZ_ABBR_ERR_CHAR;
/*
** Second, truncate long abbreviations.
*/
for (i = 0; i < sp->typecnt; ++i) {
register const struct ttinfo * const ttisp = &sp->ttis[i];
char *cp = &sp->chars[ttisp->tt_desigidx];
if (strlen(cp) > TZ_ABBR_MAX_LEN &&
strcmp(cp, GRANDPARENTED) != 0)
*(cp + TZ_ABBR_MAX_LEN) = '\0';
}
}
static bool
differ_by_repeat(const time_t t1, const time_t t0)
{
if (TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
return 0;
return t1 - t0 == SECSPERREPEAT;
}
/* Input buffer for data read from a compiled tz file. */
union input_buffer {
/* The first part of the buffer, interpreted as a header. */
struct tzhead tzhead;
/* The entire buffer. */
char buf[2 * sizeof(struct tzhead) + 2 * sizeof (struct state)
+ 4 * TZ_MAX_TIMES];
};
/* TZDIR with a trailing '/' rather than a trailing '\0'. */
static char const tzdirslash[sizeof TZDIR] = TZDIR "/";
/* Local storage needed for 'tzloadbody'. */
union local_storage {
/* The results of analyzing the file's contents after it is opened. */
struct file_analysis {
/* The input buffer. */
union input_buffer u;
/* A temporary state used for parsing a TZ string in the file. */
struct state st;
} u;
/* The file name to be opened. */
char fullname[BIGGEST(sizeof (struct file_analysis),
sizeof tzdirslash + 1024)];
};
/* Load tz data from the file named NAME into *SP. Read extended
format if DOEXTEND. Use *LSP for temporary storage. Return 0 on
success, an errno value on failure. */
static int
tzloadbody(char const *name, struct state *sp, bool doextend,
union local_storage *lsp)
{
register int i;
register int fid;
register int stored;
register ssize_t nread;
register bool doaccess;
register union input_buffer *up = &lsp->u.u;
register int tzheadsize = sizeof (struct tzhead);
sp->goback = sp->goahead = false;
if (! name) {
name = TZDEFAULT;
if (! name)
return EINVAL;
}
if (name[0] == ':')
++name;
#ifdef SUPPRESS_TZDIR
/* Do not prepend TZDIR. This is intended for specialized
applications only, due to its security implications. */
doaccess = true;
#else
doaccess = name[0] == '/';
#endif
if (!doaccess) {
char const *dot;
size_t namelen = strlen(name);
if (sizeof lsp->fullname - sizeof tzdirslash <= namelen)
return ENAMETOOLONG;
/* Create a string "TZDIR/NAME". Using sprintf here
would pull in stdio (and would fail if the
resulting string length exceeded INT_MAX!). */
memcpy(lsp->fullname, tzdirslash, sizeof tzdirslash);
strcpy(lsp->fullname + sizeof tzdirslash, name);
/* Set doaccess if NAME contains a ".." file name
component, as such a name could read a file outside
the TZDIR virtual subtree. */
for (dot = name; (dot = strchr(dot, '.')); dot++)
if ((dot == name || dot[-1] == '/') && dot[1] == '.'
&& (dot[2] == '/' || !dot[2])) {
doaccess = true;
break;
}
name = lsp->fullname;
}
if (doaccess && access(name, R_OK) != 0)
return errno;
fid = open(name, OPEN_MODE);
if (fid < 0)
return errno;
nread = read(fid, up->buf, sizeof up->buf);
if (nread < tzheadsize) {
int err = nread < 0 ? errno : EINVAL;
close(fid);
return err;
}
if (close(fid) < 0)
return errno;
for (stored = 4; stored <= 8; stored *= 2) {
int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt);
int_fast32_t ttisutcnt = detzcode(up->tzhead.tzh_ttisutcnt);
int_fast64_t prevtr = 0;
int_fast32_t prevcorr = 0;
int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt);
int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt);
int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt);
int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt);
char const *p = up->buf + tzheadsize;
/* Although tzfile(5) currently requires typecnt to be nonzero,
support future formats that may allow zero typecnt
in files that have a TZ string and no transitions. */
if (! (0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
&& 0 <= typecnt && typecnt < TZ_MAX_TYPES
&& 0 <= timecnt && timecnt < TZ_MAX_TIMES
&& 0 <= charcnt && charcnt < TZ_MAX_CHARS
&& (ttisstdcnt == typecnt || ttisstdcnt == 0)
&& (ttisutcnt == typecnt || ttisutcnt == 0)))
return EINVAL;
if (nread
< (tzheadsize /* struct tzhead */
+ timecnt * stored /* ats */
+ timecnt /* types */
+ typecnt * 6 /* ttinfos */
+ charcnt /* chars */
+ leapcnt * (stored + 4) /* lsinfos */
+ ttisstdcnt /* ttisstds */
+ ttisutcnt)) /* ttisuts */
return EINVAL;
sp->leapcnt = leapcnt;
sp->timecnt = timecnt;
sp->typecnt = typecnt;
sp->charcnt = charcnt;
/* Read transitions, discarding those out of time_t range.
But pretend the last transition before TIME_T_MIN
occurred at TIME_T_MIN. */
timecnt = 0;
for (i = 0; i < sp->timecnt; ++i) {
int_fast64_t at
= stored == 4 ? detzcode(p) : detzcode64(p);
sp->types[i] = at <= TIME_T_MAX;
if (sp->types[i]) {
time_t attime
= ((TYPE_SIGNED(time_t) ? at < TIME_T_MIN : at < 0)
? TIME_T_MIN : at);
if (timecnt && attime <= sp->ats[timecnt - 1]) {
if (attime < sp->ats[timecnt - 1])
return EINVAL;
sp->types[i - 1] = 0;
timecnt--;
}
sp->ats[timecnt++] = attime;
}
p += stored;
}
timecnt = 0;
for (i = 0; i < sp->timecnt; ++i) {
unsigned char typ = *p++;
if (sp->typecnt <= typ)
return EINVAL;
if (sp->types[i])
sp->types[timecnt++] = typ;
}
sp->timecnt = timecnt;
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
unsigned char isdst, desigidx;
ttisp = &sp->ttis[i];
ttisp->tt_utoff = detzcode(p);
p += 4;
isdst = *p++;
if (! (isdst < 2))
return EINVAL;
ttisp->tt_isdst = isdst;
desigidx = *p++;
if (! (desigidx < sp->charcnt))
return EINVAL;
ttisp->tt_desigidx = desigidx;
}
for (i = 0; i < sp->charcnt; ++i)
sp->chars[i] = *p++;
sp->chars[i] = '\0'; /* ensure '\0' at end */
/* Read leap seconds, discarding those out of time_t range. */
leapcnt = 0;
for (i = 0; i < sp->leapcnt; ++i) {
int_fast64_t tr = stored == 4 ? detzcode(p) : detzcode64(p);
int_fast32_t corr = detzcode(p + stored);
p += stored + 4;
/* Leap seconds cannot occur before the Epoch. */
if (tr < 0)
return EINVAL;
if (tr <= TIME_T_MAX) {
/* Leap seconds cannot occur more than once per UTC month,
and UTC months are at least 28 days long (minus 1
second for a negative leap second). Each leap second's
correction must differ from the previous one's by 1
second. */
if (tr - prevtr < 28 * SECSPERDAY - 1
|| (corr != prevcorr - 1 && corr != prevcorr + 1))
return EINVAL;
sp->lsis[leapcnt].ls_trans = prevtr = tr;
sp->lsis[leapcnt].ls_corr = prevcorr = corr;
leapcnt++;
}
}
sp->leapcnt = leapcnt;
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
ttisp = &sp->ttis[i];
if (ttisstdcnt == 0)
ttisp->tt_ttisstd = false;
else {
if (*p != true && *p != false)
return EINVAL;
ttisp->tt_ttisstd = *p++;
}
}
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
ttisp = &sp->ttis[i];
if (ttisutcnt == 0)
ttisp->tt_ttisut = false;
else {
if (*p != true && *p != false)
return EINVAL;
ttisp->tt_ttisut = *p++;
}
}
/*
** If this is an old file, we're done.
*/
if (up->tzhead.tzh_version[0] == '\0')
break;
nread -= p - up->buf;
memmove(up->buf, p, nread);
}
if (doextend && nread > 2 &&
up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
sp->typecnt + 2 <= TZ_MAX_TYPES) {
struct state *ts = &lsp->u.st;
up->buf[nread - 1] = '\0';
if (tzparse(&up->buf[1], ts, false)) {
/* Attempt to reuse existing abbreviations.
Without this, America/Anchorage would be right on
the edge after 2037 when TZ_MAX_CHARS is 50, as
sp->charcnt equals 40 (for LMT AST AWT APT AHST
AHDT YST AKDT AKST) and ts->charcnt equals 10
(for AKST AKDT). Reusing means sp->charcnt can
stay 40 in this example. */
int gotabbr = 0;
int charcnt = sp->charcnt;
for (i = 0; i < ts->typecnt; i++) {
char *tsabbr = ts->chars + ts->ttis[i].tt_desigidx;
int j;
for (j = 0; j < charcnt; j++)
if (strcmp(sp->chars + j, tsabbr) == 0) {
ts->ttis[i].tt_desigidx = j;
gotabbr++;
break;
}
if (! (j < charcnt)) {
int tsabbrlen = strlen(tsabbr);
if (j + tsabbrlen < TZ_MAX_CHARS) {
strcpy(sp->chars + j, tsabbr);
charcnt = j + tsabbrlen + 1;
ts->ttis[i].tt_desigidx = j;
gotabbr++;
}
}
}
if (gotabbr == ts->typecnt) {
sp->charcnt = charcnt;
/* Ignore any trailing, no-op transitions generated
by zic as they don't help here and can run afoul
of bugs in zic 2016j or earlier. */
while (1 < sp->timecnt
&& (sp->types[sp->timecnt - 1]
== sp->types[sp->timecnt - 2]))
sp->timecnt--;
for (i = 0; i < ts->timecnt; i++)
if (sp->timecnt == 0
|| (sp->ats[sp->timecnt - 1]
< ts->ats[i] + leapcorr(sp, ts->ats[i])))
break;
while (i < ts->timecnt
&& sp->timecnt < TZ_MAX_TIMES) {
sp->ats[sp->timecnt]
= ts->ats[i] + leapcorr(sp, ts->ats[i]);
sp->types[sp->timecnt] = (sp->typecnt
+ ts->types[i]);
sp->timecnt++;
i++;
}
for (i = 0; i < ts->typecnt; i++)
sp->ttis[sp->typecnt++] = ts->ttis[i];
}
}
}
if (sp->typecnt == 0)
return EINVAL;
if (sp->timecnt > 1) {
for (i = 1; i < sp->timecnt; ++i)
if (typesequiv(sp, sp->types[i], sp->types[0]) &&
differ_by_repeat(sp->ats[i], sp->ats[0])) {
sp->goback = true;
break;
}
for (i = sp->timecnt - 2; i >= 0; --i)
if (typesequiv(sp, sp->types[sp->timecnt - 1],
sp->types[i]) &&
differ_by_repeat(sp->ats[sp->timecnt - 1],
sp->ats[i])) {
sp->goahead = true;
break;
}
}
/* Infer sp->defaulttype from the data. Although this default
type is always zero for data from recent tzdb releases,
things are trickier for data from tzdb 2018e or earlier.
The first set of heuristics work around bugs in 32-bit data
generated by tzdb 2013c or earlier. The workaround is for
zones like Australia/Macquarie where timestamps before the
first transition have a time type that is not the earliest
standard-time type. See:
https://mm.icann.org/pipermail/tz/2013-May/019368.html */
/*
** If type 0 is unused in transitions,
** it's the type to use for early times.
*/
for (i = 0; i < sp->timecnt; ++i)
if (sp->types[i] == 0)
break;
i = i < sp->timecnt ? -1 : 0;
/*
** Absent the above,
** if there are transition times
** and the first transition is to a daylight time
** find the standard type less than and closest to
** the type of the first transition.
*/
if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
i = sp->types[0];
while (--i >= 0)
if (!sp->ttis[i].tt_isdst)
break;
}
/* The next heuristics are for data generated by tzdb 2018e or
earlier, for zones like EST5EDT where the first transition
is to DST. */
/*
** If no result yet, find the first standard type.
** If there is none, punt to type zero.
*/
if (i < 0) {
i = 0;
while (sp->ttis[i].tt_isdst)
if (++i >= sp->typecnt) {
i = 0;
break;
}
}
/* A simple 'sp->defaulttype = 0;' would suffice here if we
didn't have to worry about 2018e-or-earlier data. Even
simpler would be to remove the defaulttype member and just
use 0 in its place. */
sp->defaulttype = i;
return 0;
}
/* Load tz data from the file named NAME into *SP. Read extended
format if DOEXTEND. Return 0 on success, an errno value on failure. */
static int
tzload(char const *name, struct state *sp, bool doextend)
{
#ifdef ALL_STATE
union local_storage *lsp = malloc(sizeof *lsp);
if (!lsp)
return errno;
else {
int err = tzloadbody(name, sp, doextend, lsp);
free(lsp);
return err;
}
#else
union local_storage ls;
return tzloadbody(name, sp, doextend, &ls);
#endif
}
static bool
typesequiv(const struct state *sp, int a, int b)
{
register bool result;
if (sp == NULL ||
a < 0 || a >= sp->typecnt ||
b < 0 || b >= sp->typecnt)
result = false;
else {
register const struct ttinfo * ap = &sp->ttis[a];
register const struct ttinfo * bp = &sp->ttis[b];
result = (ap->tt_utoff == bp->tt_utoff
&& ap->tt_isdst == bp->tt_isdst
&& ap->tt_ttisstd == bp->tt_ttisstd
&& ap->tt_ttisut == bp->tt_ttisut
&& (strcmp(&sp->chars[ap->tt_desigidx],
&sp->chars[bp->tt_desigidx])
== 0));
}
return result;
}
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 timezone string, scan until a character that is not
** a valid character in a time zone abbreviation is found.
** Return a pointer to that character.
*/
static ATTRIBUTE_PURE 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 an extended timezone string, scan until the ending
** delimiter of the time zone abbreviation is located.
** Return a pointer to the delimiter.
**
** As with getzname above, the legal character set is actually quite
** restricted, with other characters producing undefined results.
** We don't do any checking here; checking is done later in common-case code.
*/
static ATTRIBUTE_PURE const char *
getqzname(register const char *strp, const int delim)
{
register int c;
while ((c = *strp) != '\0' && c != delim)
++strp;
return strp;
}
/*
** Given a pointer into a timezone 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 *const 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 timezone 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, int_fast32_t *const 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 * (int_fast32_t) 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 timezone 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, int_fast32_t *const offsetp)
{
register bool neg = false;
if (*strp == '-') {
neg = true;
++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 timezone 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 *const 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 = getoffset(strp, &rulep->r_time);
} else rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
return strp;
}
/*
** Given a year, a rule, and the offset from UT at the time that rule takes
** effect, calculate the year-relative time that rule takes effect.
*/
static int_fast32_t
transtime(const int year, register const struct rule *const rulep,
const int_fast32_t offset)
{
register bool leapyear;
register int_fast32_t value;
register int i;
int d, m1, yy0, yy1, yy2, dow;
INITIALIZE(value);
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 = (rulep->r_day - 1) * SECSPERDAY;
if (leapyear && rulep->r_day >= 60)
value += SECSPERDAY;