pgtz.h File Reference

#include "pgtime.h"
#include "tzfile.h"

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Go to the source code of this file.

Data Structures
struct	ttinfo
struct	lsinfo
struct	state
struct	pg_tz

Macros
#define	SMALLEST(a, b)   (((a) < (b)) ? (a) : (b))
#define	BIGGEST(a, b)   (((a) > (b)) ? (a) : (b))

Functions
int	pg_open_tzfile (const char *name, char *canonname)
int	tzload (const char *name, char *canonname, struct state *sp, bool doextend)
bool	tzparse (const char *name, struct state *sp, bool lastditch)

Macro Definition Documentation

BIGGEST

#define BIGGEST	(		a,
			b
	)		(((a) > (b)) ? (a) : (b))

Definition at line 24 of file pgtz.h.

SMALLEST

#define SMALLEST	(		a,
			b
	)		(((a) < (b)) ? (a) : (b))

Definition at line 23 of file pgtz.h.

Function Documentation

pg_open_tzfile()

int pg_open_tzfile	(	const char *	name,
		char *	canonname
	)

Definition at line 65 of file findtimezone.c.

{
    char        fullname[MAXPGPATH];
 
    if (canonname)
        strlcpy(canonname, name, TZ_STRLEN_MAX + 1);
 
    strlcpy(fullname, pg_TZDIR(), sizeof(fullname));
    if (strlen(fullname) + 1 + strlen(name) >= MAXPGPATH)
        return -1;              /* not gonna fit */
    strcat(fullname, "/");
    strcat(fullname, name);
 
    return open(fullname, O_RDONLY | PG_BINARY, 0);
}

References MAXPGPATH, name, PG_BINARY, pg_TZDIR(), scan_directory_ci(), strlcpy(), and TZ_STRLEN_MAX.

Referenced by tzloadbody().

tzload()

int tzload	(	const char *	name,
		char *	canonname,
		struct state *	sp,
		bool	doextend
	)

Definition at line 587 of file localtime.c.

{
    union local_storage *lsp = malloc(sizeof *lsp);
 
    if (!lsp)
        return errno;
    else
    {
        int         err = tzloadbody(name, canonname, sp, doextend, lsp);
 
        free(lsp);
        return err;
    }
}

References err(), free, malloc, name, and tzloadbody().

Referenced by gmtload(), pg_load_tz(), pg_tzenumerate_next(), and pg_tzset().

tzparse()

bool tzparse	(	const char *	name,
		struct state *	sp,
		bool	lastditch
	)

Definition at line 937 of file localtime.c.

{
    const char *stdname;
    const char *dstname = NULL;
    size_t      stdlen;
    size_t      dstlen;
    size_t      charcnt;
    int_fast32_t stdoffset;
    int_fast32_t dstoffset;
    char       *cp;
    bool        load_ok;
 
    stdname = name;
    if (lastditch)
    {
        /* Unlike IANA, don't assume name is exactly "GMT" */
        stdlen = strlen(name);  /* length of standard zone name */
        name += stdlen;
        stdoffset = 0;
    }
    else
    {
        if (*name == '<')
        {
            name++;
            stdname = name;
            name = getqzname(name, '>');
            if (*name != '>')
                return false;
            stdlen = name - stdname;
            name++;
        }
        else
        {
            name = getzname(name);
            stdlen = name - stdname;
        }
        if (*name == '\0')      /* we allow empty STD abbrev, unlike IANA */
            return false;
        name = getoffset(name, &stdoffset);
        if (name == NULL)
            return false;
    }
    charcnt = stdlen + 1;
    if (sizeof sp->chars < charcnt)
        return false;
 
    /*
     * The IANA code always tries to tzload(TZDEFRULES) here.  We do not want
     * to do that; it would be bad news in the lastditch case, where we can't
     * assume pg_open_tzfile() is sane yet.  Moreover, if we did load it and
     * it contains leap-second-dependent info, that would cause problems too.
     * Finally, IANA has deprecated the TZDEFRULES feature, so it presumably
     * will die at some point.  Desupporting it now seems like good
     * future-proofing.
     */
    load_ok = false;
    sp->goback = sp->goahead = false;   /* simulate failed tzload() */
    sp->leapcnt = 0;            /* intentionally assume no leap seconds */
 
    if (*name != '\0')
    {
        if (*name == '<')
        {
            dstname = ++name;
            name = getqzname(name, '>');
            if (*name != '>')
                return false;
            dstlen = name - dstname;
            name++;
        }
        else
        {
            dstname = name;
            name = getzname(name);
            dstlen = name - dstname;    /* length of DST abbr. */
        }
        if (!dstlen)
            return false;
        charcnt += dstlen + 1;
        if (sizeof sp->chars < charcnt)
            return false;
        if (*name != '\0' && *name != ',' && *name != ';')
        {
            name = getoffset(name, &dstoffset);
            if (name == NULL)
                return false;
        }
        else
            dstoffset = stdoffset - SECSPERHOUR;
        if (*name == '\0' && !load_ok)
            name = TZDEFRULESTRING;
        if (*name == ',' || *name == ';')
        {
            struct rule start;
            struct rule end;
            int         year;
            int         yearlim;
            int         timecnt;
            pg_time_t   janfirst;
            int_fast32_t janoffset = 0;
            int         yearbeg;
 
            ++name;
            if ((name = getrule(name, &start)) == NULL)
                return false;
            if (*name++ != ',')
                return false;
            if ((name = getrule(name, &end)) == NULL)
                return false;
            if (*name != '\0')
                return false;
            sp->typecnt = 2;    /* standard time and DST */
 
            /*
             * Two transitions per year, from EPOCH_YEAR forward.
             */
            init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
            init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
            sp->defaulttype = 0;
            timecnt = 0;
            janfirst = 0;
            yearbeg = EPOCH_YEAR;
 
            do
            {
                int_fast32_t yearsecs
                = year_lengths[isleap(yearbeg - 1)] * SECSPERDAY;
 
                yearbeg--;
                if (increment_overflow_time(&janfirst, -yearsecs))
                {
                    janoffset = -yearsecs;
                    break;
                }
            } while (EPOCH_YEAR - YEARSPERREPEAT / 2 < yearbeg);
 
            yearlim = yearbeg + YEARSPERREPEAT + 1;
            for (year = yearbeg; year < yearlim; year++)
            {
                int_fast32_t
                            starttime = transtime(year, &start, stdoffset),
                            endtime = transtime(year, &end, dstoffset);
                int_fast32_t
                            yearsecs = (year_lengths[isleap(year)]
                                        * SECSPERDAY);
                bool        reversed = endtime < starttime;
 
                if (reversed)
                {
                    int_fast32_t swap = starttime;
 
                    starttime = endtime;
                    endtime = swap;
                }
                if (reversed
                    || (starttime < endtime
                        && (endtime - starttime
                            < (yearsecs
                               + (stdoffset - dstoffset)))))
                {
                    if (TZ_MAX_TIMES - 2 < timecnt)
                        break;
                    sp->ats[timecnt] = janfirst;
                    if (!increment_overflow_time
                        (&sp->ats[timecnt],
                         janoffset + starttime))
                        sp->types[timecnt++] = !reversed;
                    sp->ats[timecnt] = janfirst;
                    if (!increment_overflow_time
                        (&sp->ats[timecnt],
                         janoffset + endtime))
                    {
                        sp->types[timecnt++] = reversed;
                        yearlim = year + YEARSPERREPEAT + 1;
                    }
                }
                if (increment_overflow_time
                    (&janfirst, janoffset + yearsecs))
                    break;
                janoffset = 0;
            }
            sp->timecnt = timecnt;
            if (!timecnt)
            {
                sp->ttis[0] = sp->ttis[1];
                sp->typecnt = 1;    /* Perpetual DST.  */
            }
            else if (YEARSPERREPEAT < year - yearbeg)
                sp->goback = sp->goahead = true;
        }
        else
        {
            int_fast32_t theirstdoffset;
            int_fast32_t theirdstoffset;
            int_fast32_t theiroffset;
            bool        isdst;
            int         i;
            int         j;
 
            if (*name != '\0')
                return false;
 
            /*
             * 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_utoff;
                    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_utoff;
                    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_ttisut)
                {
                    /* No adjustment to transition time */
                }
                else
                {
                    /*
                     * If daylight saving time is in effect, and the
                     * transition time was not specified as standard time, add
                     * the daylight saving 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_utoff;
                if (sp->ttis[j].tt_isdst)
                    theirdstoffset = theiroffset;
                else
                    theirstdoffset = theiroffset;
            }
 
            /*
             * Finally, fill in ttis.
             */
            init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
            init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
            sp->typecnt = 2;
            sp->defaulttype = 0;
        }
    }
    else
    {
        dstlen = 0;
        sp->typecnt = 1;        /* only standard time */
        sp->timecnt = 0;
        init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
        sp->defaulttype = 0;
    }
    sp->charcnt = charcnt;
    cp = sp->chars;
    memcpy(cp, stdname, stdlen);
    cp += stdlen;
    *cp++ = '\0';
    if (dstlen != 0)
    {
        memcpy(cp, dstname, dstlen);
        *(cp + dstlen) = '\0';
    }
    return true;
}

References state::ats, state::charcnt, charcnt, state::chars, state::defaulttype, EPOCH_YEAR, getoffset(), getqzname(), getrule(), getzname(), state::goahead, state::goback, i, if(), increment_overflow_time(), init_ttinfo(), isleap, j, state::leapcnt, name, SECSPERDAY, SECSPERHOUR, start, state::timecnt, timecnt, transtime(), ttinfo::tt_isdst, ttinfo::tt_ttisstd, ttinfo::tt_ttisut, ttinfo::tt_utoff, state::ttis, state::typecnt, state::types, TZ_MAX_TIMES, TZDEFRULESTRING, year_lengths, and YEARSPERREPEAT.

Referenced by gmtload(), pg_load_tz(), pg_tzset(), and tzloadbody().