xref: /src/lib/libc/time/zic.c

/*	$NetBSD: zic.c,v 1.81 2022/03/22 17:48:39 christos Exp $	*/
/*
** This file is in the public domain, so clarified as of
** 2006-07-17 by Arthur David Olson.
*/
/* Compile .zi time zone data into TZif binary files.  */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: zic.c,v 1.81 2022/03/22 17:48:39 christos Exp $");
#endif /* !defined lint */

/* Use the system 'time' function, instead of any private replacement.
   This avoids creating an unnecessary dependency on localtime.c.  */
#undef EPOCH_LOCAL
#undef EPOCH_OFFSET
#undef RESERVE_STD_EXT_IDS
#undef time_tz

#include "private.h"
#include "tzfile.h"

#include <fcntl.h>
#include <locale.h>
#include <signal.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <unistd.h>
#include <util.h>

typedef int_fast64_t	zic_t;
#define ZIC_MIN INT_FAST64_MIN
#define ZIC_MAX INT_FAST64_MAX
#define SCNdZIC SCNdFAST64

#ifndef ZIC_MAX_ABBR_LEN_WO_WARN
#define ZIC_MAX_ABBR_LEN_WO_WARN	6
#endif /* !defined ZIC_MAX_ABBR_LEN_WO_WARN */

#ifdef HAVE_DIRECT_H
# include <direct.h>
# include <io.h>
# undef mkdir
# define mkdir(name, mode) _mkdir(name)
#endif

#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef S_IRUSR
#define MKDIR_UMASK (S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
#else
#define MKDIR_UMASK 0755
#endif

/* The maximum ptrdiff_t value, for pre-C99 platforms.  */
#ifndef PTRDIFF_MAX
static ptrdiff_t const PTRDIFF_MAX = MAXVAL(ptrdiff_t, TYPE_BIT(ptrdiff_t));
#endif

/* The minimum alignment of a type, for pre-C11 platforms.  */
#if __STDC_VERSION__ < 201112
# define _Alignof(type) offsetof(struct { char a; type b; }, b)
#endif

/* The type for line numbers.  Use PRIdMAX to format them; formerly
   there was also "#define PRIdLINENO PRIdMAX" and formats used
   PRIdLINENO, but xgettext cannot grok that.  */
typedef intmax_t lineno;

struct rule {
	const char *	r_filename;
	lineno		r_linenum;
	const char *	r_name;

	zic_t		r_loyear;	/* for example, 1986 */
	zic_t		r_hiyear;	/* for example, 1986 */
	bool		r_lowasnum;
	bool		r_hiwasnum;

	int		r_month;	/* 0..11 */

	int		r_dycode;	/* see below */
	int		r_dayofmonth;
	int		r_wday;

	zic_t		r_tod;		/* time from midnight */
	bool		r_todisstd;	/* is r_tod standard time? */
	bool		r_todisut;	/* is r_tod UT? */
	bool		r_isdst;	/* is this daylight saving time? */
	zic_t		r_save;		/* offset from standard time */
	const char *	r_abbrvar;	/* variable part of abbreviation */

	bool		r_todo;		/* a rule to do (used in outzone) */
	zic_t		r_temp;		/* used in outzone */
};

/*
**	r_dycode		r_dayofmonth	r_wday
*/

#define DC_DOM		0	/* 1..31 */	/* unused */
#define DC_DOWGEQ	1	/* 1..31 */	/* 0..6 (Sun..Sat) */
#define DC_DOWLEQ	2	/* 1..31 */	/* 0..6 (Sun..Sat) */

struct zone {
	const char *	z_filename;
	lineno		z_linenum;

	const char *	z_name;
	zic_t		z_stdoff;
	char *		z_rule;
	const char *	z_format;
	char		z_format_specifier;

	bool		z_isdst;
	zic_t		z_save;

	struct rule *	z_rules;
	ptrdiff_t	z_nrules;

	struct rule	z_untilrule;
	zic_t		z_untiltime;
};

#if !HAVE_POSIX_DECLS
extern int	getopt(int argc, char * const argv[],
			const char * options);
extern int	link(const char * target, const char * linkname);
extern char *	optarg;
extern int	optind;
#endif

#if ! HAVE_LINK
# define link(target, linkname) (errno = ENOTSUP, -1)
#endif
#if ! HAVE_SYMLINK
# define readlink(file, buf, size) (errno = ENOTSUP, -1)
# define symlink(target, linkname) (errno = ENOTSUP, -1)
# define S_ISLNK(m) 0
#endif
#ifndef AT_SYMLINK_FOLLOW
# define linkat(targetdir, target, linknamedir, linkname, flag) \
    (itssymlink(target) ? (errno = ENOTSUP, -1) : link(target, linkname))
#endif

static void	addtt(zic_t starttime, int type);
static int	addtype(zic_t, char const *, bool, bool, bool);
static void	leapadd(zic_t, int, int);
static void	adjleap(void);
static void	associate(void);
static void	dolink(const char *, const char *, bool);
static char **	getfields(char * buf);
static zic_t	gethms(const char * string, const char * errstring);
static zic_t	getsave(char *, bool *);
static void	inexpires(char **, int);
static void	infile(const char * filename);
static void	inleap(char ** fields, int nfields);
static void	inlink(char ** fields, int nfields);
static void	inrule(char ** fields, int nfields);
static bool	inzcont(char ** fields, int nfields);
static bool	inzone(char ** fields, int nfields);
static bool	inzsub(char **, int, bool);
static bool	itssymlink(char const *);
static bool	is_alpha(char a);
static char	lowerit(char);
static void	mkdirs(char const *, bool);
static void	newabbr(const char * abbr);
static zic_t	oadd(zic_t t1, zic_t t2);
static void	outzone(const struct zone * zp, ptrdiff_t ntzones);
static zic_t	rpytime(const struct rule * rp, zic_t wantedy);
static bool	rulesub(struct rule * rp,
			const char * loyearp, const char * hiyearp,
			const char * typep, const char * monthp,
			const char * dayp, const char * timep);
static zic_t	tadd(zic_t t1, zic_t t2);

/* Bound on length of what %z can expand to.  */
enum { PERCENT_Z_LEN_BOUND = sizeof "+995959" - 1 };

/* If true, work around a bug in Qt 5.6.1 and earlier, which mishandles
   TZif files whose POSIX-TZ-style strings contain '<'; see
   QTBUG-53071 <https://bugreports.qt.io/browse/QTBUG-53071>.  This
   workaround will no longer be needed when Qt 5.6.1 and earlier are
   obsolete, say in the year 2021.  */
#ifndef WORK_AROUND_QTBUG_53071
enum { WORK_AROUND_QTBUG_53071 = true };
#endif

static int		charcnt;
static bool		errors;
static bool		warnings;
static const char *	filename;
static int		leapcnt;
static bool		leapseen;
static zic_t		leapminyear;
static zic_t		leapmaxyear;
static lineno		linenum;
static size_t		max_abbrvar_len = PERCENT_Z_LEN_BOUND;
static size_t		max_format_len;
static zic_t		max_year;
static zic_t		min_year;
static bool		noise;
static const char *	rfilename;
static lineno		rlinenum;
static const char *	progname;
static ptrdiff_t	timecnt;
static ptrdiff_t	timecnt_alloc;
static int		typecnt;
static int		unspecifiedtype;

/*
** Line codes.
*/

#define LC_RULE		0
#define LC_ZONE		1
#define LC_LINK		2
#define LC_LEAP		3
#define LC_EXPIRES	4

/*
** Which fields are which on a Zone line.
*/

#define ZF_NAME		1
#define ZF_STDOFF	2
#define ZF_RULE		3
#define ZF_FORMAT	4
#define ZF_TILYEAR	5
#define ZF_TILMONTH	6
#define ZF_TILDAY	7
#define ZF_TILTIME	8
#define ZONE_MINFIELDS	5
#define ZONE_MAXFIELDS	9

/*
** Which fields are which on a Zone continuation line.
*/

#define ZFC_STDOFF	0
#define ZFC_RULE	1
#define ZFC_FORMAT	2
#define ZFC_TILYEAR	3
#define ZFC_TILMONTH	4
#define ZFC_TILDAY	5
#define ZFC_TILTIME	6
#define ZONEC_MINFIELDS	3
#define ZONEC_MAXFIELDS	7

/*
** Which files are which on a Rule line.
*/

#define RF_NAME		1
#define RF_LOYEAR	2
#define RF_HIYEAR	3
#define RF_COMMAND	4
#define RF_MONTH	5
#define RF_DAY		6
#define RF_TOD		7
#define RF_SAVE		8
#define RF_ABBRVAR	9
#define RULE_FIELDS	10

/*
** Which fields are which on a Link line.
*/

#define LF_TARGET	1
#define LF_LINKNAME	2
#define LINK_FIELDS	3

/*
** Which fields are which on a Leap line.
*/

#define LP_YEAR		1
#define LP_MONTH	2
#define LP_DAY		3
#define LP_TIME		4
#define LP_CORR		5
#define LP_ROLL		6
#define LEAP_FIELDS	7

/* Expires lines are like Leap lines, except without CORR and ROLL fields.  */
#define EXPIRES_FIELDS	5

/*
** Year synonyms.
*/

#define YR_MINIMUM	0
#define YR_MAXIMUM	1
#define YR_ONLY		2

static struct rule *	rules;
static ptrdiff_t	nrules;	/* number of rules */
static ptrdiff_t	nrules_alloc;

static struct zone *	zones;
static ptrdiff_t	nzones;	/* number of zones */
static ptrdiff_t	nzones_alloc;

struct link {
	const char *	l_filename;
	lineno		l_linenum;
	const char *	l_target;
	const char *	l_linkname;
};

static struct link *	links;
static ptrdiff_t	nlinks;
static ptrdiff_t	nlinks_alloc;

struct lookup {
	const char *	l_word;
	const int	l_value;
};

static struct lookup const *	byword(const char * string,
					const struct lookup * lp);

static struct lookup const zi_line_codes[] = {
	{ "Rule",	LC_RULE },
	{ "Zone",	LC_ZONE },
	{ "Link",	LC_LINK },
	{ NULL,		0 }
};
static struct lookup const leap_line_codes[] = {
	{ "Leap",	LC_LEAP },
	{ "Expires",	LC_EXPIRES },
	{ NULL,		0}
};

static struct lookup const	mon_names[] = {
	{ "January",	TM_JANUARY },
	{ "February",	TM_FEBRUARY },
	{ "March",	TM_MARCH },
	{ "April",	TM_APRIL },
	{ "May",	TM_MAY },
	{ "June",	TM_JUNE },
	{ "July",	TM_JULY },
	{ "August",	TM_AUGUST },
	{ "September",	TM_SEPTEMBER },
	{ "October",	TM_OCTOBER },
	{ "November",	TM_NOVEMBER },
	{ "December",	TM_DECEMBER },
	{ NULL,		0 }
};

static struct lookup const	wday_names[] = {
	{ "Sunday",	TM_SUNDAY },
	{ "Monday",	TM_MONDAY },
	{ "Tuesday",	TM_TUESDAY },
	{ "Wednesday",	TM_WEDNESDAY },
	{ "Thursday",	TM_THURSDAY },
	{ "Friday",	TM_FRIDAY },
	{ "Saturday",	TM_SATURDAY },
	{ NULL,		0 }
};

static struct lookup const	lasts[] = {
	{ "last-Sunday",	TM_SUNDAY },
	{ "last-Monday",	TM_MONDAY },
	{ "last-Tuesday",	TM_TUESDAY },
	{ "last-Wednesday",	TM_WEDNESDAY },
	{ "last-Thursday",	TM_THURSDAY },
	{ "last-Friday",	TM_FRIDAY },
	{ "last-Saturday",	TM_SATURDAY },
	{ NULL,			0 }
};

static struct lookup const	begin_years[] = {
	{ "minimum",	YR_MINIMUM },
	{ "maximum",	YR_MAXIMUM },
	{ NULL,		0 }
};

static struct lookup const	end_years[] = {
	{ "minimum",	YR_MINIMUM },
	{ "maximum",	YR_MAXIMUM },
	{ "only",	YR_ONLY },
	{ NULL,		0 }
};

static struct lookup const	leap_types[] = {
	{ "Rolling",	true },
	{ "Stationary",	false },
	{ NULL,		0 }
};

static const int	len_months[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	len_years[2] = {
	DAYSPERNYEAR, DAYSPERLYEAR
};

static struct attype {
	zic_t		at;
	bool		dontmerge;
	unsigned char	type;
} *			attypes;
static zic_t		utoffs[TZ_MAX_TYPES];
static char		isdsts[TZ_MAX_TYPES];
static unsigned char	desigidx[TZ_MAX_TYPES];
static bool		ttisstds[TZ_MAX_TYPES];
static bool		ttisuts[TZ_MAX_TYPES];
static char		chars[TZ_MAX_CHARS];
static zic_t		trans[TZ_MAX_LEAPS];
static zic_t		corr[TZ_MAX_LEAPS];
static char		roll[TZ_MAX_LEAPS];

/*
** Memory allocation.
*/

static _Noreturn void
memory_exhausted(const char *msg)
{
	fprintf(stderr, _("%s: Memory exhausted: %s\n"), progname, msg);
	exit(EXIT_FAILURE);
}

static ATTRIBUTE_PURE size_t
size_product(size_t nitems, size_t itemsize)
{
	if (SIZE_MAX / itemsize < nitems)
		memory_exhausted(_("size overflow"));
	return nitems * itemsize;
}

static ATTRIBUTE_PURE size_t
align_to(size_t size, size_t alignment)
{
  size_t aligned_size = size + alignment - 1;
  aligned_size -= aligned_size % alignment;
  if (aligned_size < size)
    memory_exhausted(_("alignment overflow"));
  return aligned_size;
}

#if !HAVE_STRDUP
static char *
strdup(char const *str)
{
	char *result = malloc(strlen(str) + 1);
	return result ? strcpy(result, str) : result;
}
#endif

static void *
memcheck(void *ptr)
{
	if (ptr == NULL)
	  memory_exhausted(strerror(HAVE_MALLOC_ERRNO ? errno : ENOMEM));
	return ptr;
}

static void * ATTRIBUTE_MALLOC
zic_malloc(size_t size)
{
	return memcheck(malloc(size));
}

static void *
zic_realloc(void *ptr, size_t size)
{
	return memcheck(realloc(ptr, size));
}

static char * ATTRIBUTE_MALLOC
ecpyalloc(char const *str)
{
	return memcheck(strdup(str));
}

static void *
growalloc(void *ptr, size_t itemsize, ptrdiff_t nitems, ptrdiff_t *nitems_alloc)
{
	if (nitems < *nitems_alloc)
		return ptr;
	else {
		ptrdiff_t nitems_max = PTRDIFF_MAX - WORK_AROUND_QTBUG_53071;
		ptrdiff_t amax = (ptrdiff_t)((size_t)nitems_max < SIZE_MAX ?
		    (size_t)nitems_max : SIZE_MAX);
		if ((amax - 1) / 3 * 2 < *nitems_alloc)
			memory_exhausted(_("integer overflow"));
		*nitems_alloc += (*nitems_alloc >> 1) + 1;
		return zic_realloc(ptr, size_product(*nitems_alloc, itemsize));
	}
}

/*
** Error handling.
*/

static void
eats(char const *name, lineno num, char const *rname, lineno rnum)
{
	filename = name;
	linenum = num;
	rfilename = rname;
	rlinenum = rnum;
}

static void
eat(char const *name, lineno num)
{
	eats(name, num, NULL, -1);
}

static void ATTRIBUTE_FORMAT((printf, 1, 0))
verror(const char *const string, va_list args)
{
	/*
	** Match the format of "cc" to allow sh users to
	**	zic ... 2>&1 | error -t "*" -v
	** on BSD systems.
	*/
	if (filename)
	  fprintf(stderr, _("\"%s\", line %"PRIdMAX": "), filename, linenum);
	vfprintf(stderr, string, args);
	if (rfilename != NULL)
		fprintf(stderr, _(" (rule from \"%s\", line %"PRIdMAX")"),
			rfilename, rlinenum);
	fprintf(stderr, "\n");
}

static void ATTRIBUTE_FORMAT((printf, 1, 2))
error(const char *const string, ...)
{
	va_list args;
	va_start(args, string);
	verror(string, args);
	va_end(args);
	errors = true;
}

static void ATTRIBUTE_FORMAT((printf, 1, 2))
warning(const char *const string, ...)
{
	va_list args;
	fprintf(stderr, _("warning: "));
	va_start(args, string);
	verror(string, args);
	va_end(args);
	warnings = true;
}

/* Close STREAM.  If it had an I/O error, report it against DIR/NAME,
   remove TEMPNAME if nonnull, and then exit.  */
static void
close_file(FILE *stream, char const *dir, char const *name,
	   char const *tempname)
{
  char const *e = (ferror(stream) ? _("I/O error")
		   : fclose(stream) != 0 ? strerror(errno) : NULL);
  if (e) {
    fprintf(stderr, "%s: %s%s%s%s%s\n", progname,
	    dir ? dir : "", dir ? "/" : "",
	    name ? name : "", name ? ": " : "",
	    e);
    if (tempname)
      remove(tempname);
    exit(EXIT_FAILURE);
  }
}

static _Noreturn void
usage(FILE *stream, int status)
{
  fprintf(stream,
	  _("%s: usage is %s [ --version ] [ --help ] [ -v ] \\\n"
	    "\t[ -b {slim|fat} ] [ -d directory ] [ -l localtime ]"
	    " [ -L leapseconds ] \\\n"
	    "\t[ -p posixrules ] [ -r '[@lo][/@hi]' ] [ -t localtime-link ] \\\n"
	    "\t[ filename ... ]\n\n"
	    "Report bugs to %s.\n"),
	  progname, progname, REPORT_BUGS_TO);
  if (status == EXIT_SUCCESS)
    close_file(stream, NULL, NULL, NULL);
  exit(status);
}

/* Change the working directory to DIR, possibly creating DIR and its
   ancestors.  After this is done, all files are accessed with names
   relative to DIR.  */
static void
change_directory(char const *dir)
{
  if (chdir(dir) != 0) {
    int chdir_errno = errno;
    if (chdir_errno == ENOENT) {
      mkdirs(dir, false);
      chdir_errno = chdir(dir) == 0 ? 0 : errno;
    }
    if (chdir_errno != 0) {
      fprintf(stderr, _("%s: Can't chdir to %s: %s\n"),
	      progname, dir, strerror(chdir_errno));
      exit(EXIT_FAILURE);
    }
  }
}

/* Simple signal handling: just set a flag that is checked
   periodically outside critical sections.  To set up the handler,
   prefer sigaction if available to close a signal race.  */

static sig_atomic_t got_signal;

static void
signal_handler(int sig)
{
#ifndef SA_SIGINFO
  signal(sig, signal_handler);
#endif
  got_signal = sig;
}

/* Arrange for SIGINT etc. to be caught by the handler.  */
static void
catch_signals(void)
{
  static int const signals[] = {
#ifdef SIGHUP
    SIGHUP,
#endif
    SIGINT,
#ifdef SIGPIPE
    SIGPIPE,
#endif
    SIGTERM
  };
  size_t i;
  for (i = 0; i < sizeof signals / sizeof signals[0]; i++) {
#ifdef SA_SIGINFO
    struct sigaction act0, act;
    act.sa_handler = signal_handler;
    sigemptyset(&act.sa_mask);
    act.sa_flags = 0;
    if (sigaction(signals[i], &act, &act0) == 0
	&& ! (act0.sa_flags & SA_SIGINFO) && act0.sa_handler == SIG_IGN) {
      sigaction(signals[i], &act0, NULL);
      got_signal = 0;
    }
#else
    if (signal(signals[i], signal_handler) == SIG_IGN) {
      signal(signals[i], SIG_IGN);
      got_signal = 0;
    }
#endif
  }
}

/* If a signal has arrived, terminate zic with appropriate status.  */
static void
check_for_signal(void)
{
  int sig = got_signal;
  if (sig) {
    signal(sig, SIG_DFL);
    raise(sig);
    abort(); /* A bug in 'raise'.  */
  }
}

#define TIME_T_BITS_IN_FILE 64

/* The minimum and maximum values representable in a TZif file.  */
static zic_t const min_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
static zic_t const max_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);

/* The minimum, and one less than the maximum, values specified by
   the -r option.  These default to MIN_TIME and MAX_TIME.  */
static zic_t lo_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
static zic_t hi_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);

/* The time specified by an Expires line, or negative if no such line.  */
static zic_t leapexpires = -1;

/* Set the time range of the output to TIMERANGE.
   Return true if successful.  */
static bool
timerange_option(char *timerange)
{
  intmax_t lo = min_time, hi = max_time;
  char *lo_end = timerange, *hi_end;
  if (*timerange == '@') {
    errno = 0;
    lo = strtoimax(timerange + 1, &lo_end, 10);
    if (lo_end == timerange + 1 || (lo == INTMAX_MAX && errno == ERANGE))
      return false;
  }
  hi_end = lo_end;
  if (lo_end[0] == '/' && lo_end[1] == '@') {
    errno = 0;
    hi = strtoimax(lo_end + 2, &hi_end, 10);
    if (hi_end == lo_end + 2 || hi == INTMAX_MIN)
      return false;
    hi -= ! (hi == INTMAX_MAX && errno == ERANGE);
  }
  if (*hi_end || hi < lo || max_time < lo || hi < min_time)
    return false;
  lo_time = lo < min_time ? min_time : lo;
  hi_time = max_time < hi ? max_time : hi;
  return true;
}

static const char *	psxrules;
static const char *	lcltime;
static const char *	directory;
static const char *	leapsec;
static const char *	tzdefault;

/* -1 if the TZif output file should be slim, 0 if default, 1 if the
   output should be fat for backward compatibility.  ZIC_BLOAT_DEFAULT
   determines the default.  */
static int bloat;

static bool
want_bloat(void)
{
  return 0 <= bloat;
}

#ifndef ZIC_BLOAT_DEFAULT
# define ZIC_BLOAT_DEFAULT "slim"
#endif

int
main(int argc, char **argv)
{
	int	c, k;
	ptrdiff_t	i, j;
	bool timerange_given = false;

#ifdef S_IWGRP
	umask(umask(S_IWGRP | S_IWOTH) | (S_IWGRP | S_IWOTH));
#endif
#if HAVE_GETTEXT
	setlocale(LC_MESSAGES, "");
#ifdef TZ_DOMAINDIR
	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
#endif /* defined TEXTDOMAINDIR */
	textdomain(TZ_DOMAIN);
#endif /* HAVE_GETTEXT */
	progname = argv[0];
	if (TYPE_BIT(zic_t) < 64) {
		fprintf(stderr, "%s: %s\n", progname,
			_("wild compilation-time specification of zic_t"));
		return EXIT_FAILURE;
	}
	for (k = 1; k < argc; k++)
		if (strcmp(argv[k], "--version") == 0) {
			printf("zic %s%s\n", PKGVERSION, TZVERSION);
			close_file(stdout, NULL, NULL, NULL);
			return EXIT_SUCCESS;
		} else if (strcmp(argv[k], "--help") == 0) {
			usage(stdout, EXIT_SUCCESS);
		}
	while ((c = getopt(argc, argv, "b:d:l:L:p:r:st:vy:")) != EOF && c != -1)
		switch (c) {
			default:
				usage(stderr, EXIT_FAILURE);
			case 'b':
				if (strcmp(optarg, "slim") == 0) {
				  if (0 < bloat)
				    error(_("incompatible -b options"));
				  bloat = -1;
				} else if (strcmp(optarg, "fat") == 0) {
				  if (bloat < 0)
				    error(_("incompatible -b options"));
				  bloat = 1;
				} else
				  error(_("invalid option: -b '%s'"), optarg);
				break;
			case 'd':
				if (directory == NULL)
					directory = optarg;
				else {
					fprintf(stderr,
_("%s: More than one -d option specified\n"),
						progname);
					return EXIT_FAILURE;
				}
				break;
			case 'l':
				if (lcltime == NULL)
					lcltime = optarg;
				else {
					fprintf(stderr,
_("%s: More than one -l option specified\n"),
						progname);
					return EXIT_FAILURE;
				}
				break;
			case 'p':
				if (psxrules == NULL)
					psxrules = optarg;
				else {
					fprintf(stderr,
_("%s: More than one -p option specified\n"),
						progname);
					return EXIT_FAILURE;
				}
				break;
			case 't':
				if (tzdefault != NULL) {
				  fprintf(stderr,
					  _("%s: More than one -t option"
					    " specified\n"),
					  progname);
				  return EXIT_FAILURE;
				}
				tzdefault = optarg;
				break;
			case 'y':
				warning(_("-y ignored"));
				break;
			case 'L':
				if (leapsec == NULL)
					leapsec = optarg;
				else {
					fprintf(stderr,
_("%s: More than one -L option specified\n"),
						progname);
					return EXIT_FAILURE;
				}
				break;
			case 'v':
				noise = true;
				break;
			case 'r':
				if (timerange_given) {
				  fprintf(stderr,
_("%s: More than one -r option specified\n"),
					  progname);
				  return EXIT_FAILURE;
				}
				if (! timerange_option(optarg)) {
				  fprintf(stderr,
_("%s: invalid time range: %s\n"),
					  progname, optarg);
				  return EXIT_FAILURE;
				}
				timerange_given = true;
				break;
			case 's':
				warning(_("-s ignored"));
				break;
		}
	if (optind == argc - 1 && strcmp(argv[optind], "=") == 0)
		usage(stderr, EXIT_FAILURE);	/* usage message by request */
	if (bloat == 0) {
	  static char const bloat_default[] = ZIC_BLOAT_DEFAULT;
	  if (strcmp(bloat_default, "slim") == 0)
	    bloat = -1;
	  else if (strcmp(bloat_default, "fat") == 0)
	    bloat = 1;
	  else
	    abort(); /* Configuration error.  */
	}
	if (directory == NULL)
		directory = TZDIR;
	if (tzdefault == NULL)
		tzdefault = TZDEFAULT;

	if (optind < argc && leapsec != NULL) {
		infile(leapsec);
		adjleap();
	}

	for (k = optind; k < argc; k++)
		infile(argv[k]);
	if (errors)
		return EXIT_FAILURE;
	associate();
	change_directory(directory);
	catch_signals();
	for (i = 0; i < nzones; i = j) {
		/*
		** Find the next non-continuation zone entry.
		*/
		for (j = i + 1; j < nzones && zones[j].z_name == NULL; ++j)
			continue;
		outzone(&zones[i], j - i);
	}
	/*
	** Make links.
	*/
	for (i = 0; i < nlinks; ++i) {
		eat(links[i].l_filename, links[i].l_linenum);
		dolink(links[i].l_target, links[i].l_linkname, false);
		if (noise)
			for (j = 0; j < nlinks; ++j)
				if (strcmp(links[i].l_linkname,
					links[j].l_target) == 0)
						warning(_("link to link"));
	}
	if (lcltime != NULL) {
		eat(_("command line"), 1);
		dolink(lcltime, tzdefault, true);
	}
	if (psxrules != NULL) {
		eat(_("command line"), 1);
		dolink(psxrules, TZDEFRULES, true);
	}
	if (warnings && (ferror(stderr) || fclose(stderr) != 0))
	  return EXIT_FAILURE;
	return errors ? EXIT_FAILURE : EXIT_SUCCESS;
}

static bool
componentcheck(char const *name, char const *component,
	       char const *component_end)
{
	enum { component_len_max = 14 };
	ptrdiff_t component_len = component_end - component;
	if (component_len == 0) {
	  if (!*name)
	    error(_("empty file name"));
	  else
	    error(_(component == name
		     ? "file name '%s' begins with '/'"
		     : *component_end
		     ? "file name '%s' contains '//'"
		     : "file name '%s' ends with '/'"),
		   name);
	  return false;
	}
	if (0 < component_len && component_len <= 2
	    && component[0] == '.' && component_end[-1] == '.') {
	  int len = component_len;
	  error(_("file name '%s' contains '%.*s' component"),
		name, len, component);
	  return false;
	}
	if (noise) {
	  if (0 < component_len && component[0] == '-')
	    warning(_("file name '%s' component contains leading '-'"),
		    name);
	  if (component_len_max < component_len)
	    warning(_("file name '%s' contains overlength component"
		      " '%.*s...'"),
		    name, component_len_max, component);
	}
	return true;
}

static bool
namecheck(const char *name)
{
	char const *cp;

	/* Benign characters in a portable file name.  */
	static char const benign[] =
	  "-/_"
	  "abcdefghijklmnopqrstuvwxyz"
	  "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

	/* Non-control chars in the POSIX portable character set,
	   excluding the benign characters.  */
	static char const printable_and_not_benign[] =
	  " !\"#$%&'()*+,.0123456789:;<=>?@[\\]^`{|}~";

	char const *component = name;
	for (cp = name; *cp; cp++) {
		unsigned char c = *cp;
		if (noise && !strchr(benign, c)) {
			warning((strchr(printable_and_not_benign, c)
				 ? _("file name '%s' contains byte '%c'")
				 : _("file name '%s' contains byte '\\%o'")),
				name, c);
		}
		if (c == '/') {
			if (!componentcheck(name, component, cp))
			  return false;
			component = cp + 1;
		}
	}
	return componentcheck(name, component, cp);
}

/* Generate a randomish name in the same directory as *NAME.  If
   *NAMEALLOC, put the name into *NAMEALLOC which is assumed to be
   that returned by a previous call and is thus already almost set up
   and equal to *NAME; otherwise, allocate a new name and put its
   address into both *NAMEALLOC and *NAME.  */
static void
random_dirent(char const **name, char **namealloc)
{
  char const *src = *name;
  char *dst = *namealloc;
  static char const prefix[] = ".zic";
  static char const alphabet[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  enum { prefixlen = sizeof prefix - 1, alphabetlen = sizeof alphabet - 1 };
  int suffixlen = 6;
  char const *lastslash = strrchr(src, '/');
  ptrdiff_t dirlen = lastslash ? lastslash + 1 - src : 0;
  static unsigned short initialized;
  int i;

  if (!dst) {
    dst = emalloc(dirlen + prefixlen + suffixlen + 1);
    memcpy(dst, src, dirlen);
    memcpy(dst + dirlen, prefix, prefixlen);
    dst[dirlen + prefixlen + suffixlen] = '\0';
    *name = *namealloc = dst;
  }

  /* This randomization is not the best, but is portable to C89.  */
  if (!initialized++) {
    unsigned now = time(NULL);
    srand(rand() ^ now);
  }
  for (i = 0; i < suffixlen; i++)
    dst[dirlen + prefixlen + i] = alphabet[rand() % alphabetlen];
}

/* Prepare to write to the file *OUTNAME, using *TEMPNAME to store the
   name of the temporary file that will eventually be renamed to
   *OUTNAME.  Assign the temporary file's name to both *OUTNAME and
   *TEMPNAME.  If *TEMPNAME is null, allocate the name of any such
   temporary file; otherwise, reuse *TEMPNAME's storage, which is
   already set up and only needs its trailing suffix updated.  */
static FILE *
open_outfile(char const **outname, char **tempname)
{
#if __STDC_VERSION__ < 201112
  static char const fopen_mode[] = "wb";
#else
  static char const fopen_mode[] = "wbx";
#endif

  FILE *fp;
  bool dirs_made = false;
  if (!*tempname)
    random_dirent(outname, tempname);

  while (! (fp = fopen(*outname, fopen_mode))) {
    int fopen_errno = errno;
    if (fopen_errno == ENOENT && !dirs_made) {
      mkdirs(*outname, true);
      dirs_made = true;
    } else if (fopen_errno == EEXIST)
      random_dirent(outname, tempname);
    else {
      fprintf(stderr, _("%s: Can't create %s/%s: %s\n"),
	      progname, directory, *outname, strerror(fopen_errno));
      exit(EXIT_FAILURE);
    }
  }

  return fp;
}

/* If TEMPNAME, the result is in the temporary file TEMPNAME even
   though the user wanted it in NAME, so rename TEMPNAME to NAME.
   Report an error and exit if there is trouble.  Also, free TEMPNAME.  */
static void
rename_dest(char *tempname, char const *name)
{
  if (tempname) {
    if (rename(tempname, name) != 0) {
      int rename_errno = errno;
      remove(tempname);
      fprintf(stderr, _("%s: rename to %s/%s: %s\n"),
	      progname, directory, name, strerror(rename_errno));
      exit(EXIT_FAILURE);
    }
    free(tempname);
  }
}

/* Create symlink contents suitable for symlinking FROM to TO, as a
   freshly allocated string.  FROM should be a relative file name, and
   is relative to the global variable DIRECTORY.  TO can be either
   relative or absolute.  */
static char *
relname(char const *target, char const *linkname)
{
  size_t i, taillen, dotdotetcsize;
  size_t dir_len = 0, dotdots = 0, linksize = SIZE_MAX;
  char const *f = target;
  char *result = NULL;
  if (*linkname == '/') {
    /* Make F absolute too.  */
    size_t len = strlen(directory);
    bool needslash = len && directory[len - 1] != '/';
    linksize = len + needslash + strlen(target) + 1;
    f = result = emalloc(linksize);
    strcpy(result, directory);
    result[len] = '/';
    strcpy(result + len + needslash, target);
  }
  for (i = 0; f[i] && f[i] == linkname[i]; i++)
    if (f[i] == '/')
      dir_len = i + 1;
  for (; linkname[i]; i++)
    dotdots += linkname[i] == '/' && linkname[i - 1] != '/';
  taillen = strlen(f + dir_len);
  dotdotetcsize = 3 * dotdots + taillen + 1;
  if (dotdotetcsize <= linksize) {
    if (!result)
      result = emalloc(dotdotetcsize);
    for (i = 0; i < dotdots; i++)
      memcpy(result + 3 * i, "../", 3);
    memmove(result + 3 * dotdots, f + dir_len, taillen + 1);
  }
  return result;
}

static void
dolink(char const *target, char const *linkname, bool staysymlink)
{
	bool linkdirs_made = false;
	int link_errno;
	char *tempname = NULL;
	char const *outname = linkname;

	check_for_signal();

	if (strcmp(target, "-") == 0) {
	  if (remove(linkname) == 0 || errno == ENOENT || errno == ENOTDIR)
	    return;
	  else {
	    char const *e = strerror(errno);
	    fprintf(stderr, _("%s: Can't remove %s/%s: %s\n"),
		    progname, directory, linkname, e);
	    exit(EXIT_FAILURE);
	  }
	}

	while (true) {
	  if (linkat(AT_FDCWD, target, AT_FDCWD, outname, AT_SYMLINK_FOLLOW)
	      == 0) {
	    link_errno = 0;
	    break;
	  }
	  link_errno = errno;
	  if (link_errno == EXDEV || link_errno == ENOTSUP)
	    break;

	  if (link_errno == EEXIST) {
	    staysymlink &= !tempname;
	    random_dirent(&outname, &tempname);
	    if (staysymlink && itssymlink(linkname))
	      break;
	  } else if (link_errno == ENOENT && !linkdirs_made) {
	    mkdirs(linkname, true);
	    linkdirs_made = true;
	  } else {
	    fprintf(stderr, _("%s: Can't link %s/%s to %s/%s: %s\n"),
		    progname, directory, target, directory, outname,
		    strerror(link_errno));
	    exit(EXIT_FAILURE);
	  }
	}
	if (link_errno != 0) {
	  bool absolute = *target == '/';
	  char *linkalloc = absolute ? NULL : relname(target, linkname);
	  char const *contents = absolute ? target : linkalloc;
	  int symlink_errno;

	  while (true) {
	    if (symlink(contents, outname) == 0) {
	      symlink_errno = 0;
	      break;
	    }
	    symlink_errno = errno;
	    if (symlink_errno == EEXIST)
	      random_dirent(&outname, &tempname);
	    else if (symlink_errno == ENOENT && !linkdirs_made) {
	      mkdirs(linkname, true);
	      linkdirs_made = true;
	    } else
	      break;
	  }
	  free(linkalloc);
	  if (symlink_errno == 0) {
	    if (link_errno != ENOTSUP && link_errno != EEXIST)
	      warning(_("symbolic link used because hard link failed: %s"),
		      strerror(link_errno));
	  } else {
	    FILE *fp, *tp;
	    int c;
	    fp = fopen(target, "rb");
	    if (!fp) {
	      char const *e = strerror(errno);
	      fprintf(stderr, _("%s: Can't read %s/%s: %s\n"),
		      progname, directory, target, e);
	      exit(EXIT_FAILURE);
	    }
	    tp = open_outfile(&outname, &tempname);
	    while ((c = getc(fp)) != EOF)
	      putc(c, tp);
	    close_file(tp, directory, linkname, tempname);
	    close_file(fp, directory, target, NULL);
	    if (link_errno != ENOTSUP)
	      warning(_("copy used because hard link failed: %s"),
		      strerror(link_errno));
	    else if (symlink_errno != ENOTSUP)
	      warning(_("copy used because symbolic link failed: %s"),
		      strerror(symlink_errno));
	  }
	}
	rename_dest(tempname, linkname);
}

/* Return true if NAME is a symbolic link.  */
static bool
itssymlink(char const *name)
{
  char c;
  return 0 <= readlink(name, &c, 1);
}

/*
** Associate sets of rules with zones.
*/

/*
** Sort by rule name.
*/

static int
rcomp(const void *cp1, const void *cp2)
{
  struct rule const *r1 = cp1, *r2 = cp2;
  return strcmp(r1->r_name, r2->r_name);
}

static void
associate(void)
{
	struct zone *	zp;
	struct rule *	rp;
	ptrdiff_t	i, j, base, out;

	if (nrules != 0) {
		qsort(rules, (size_t)nrules, sizeof *rules, rcomp);
		for (i = 0; i < nrules - 1; ++i) {
			if (strcmp(rules[i].r_name,
				rules[i + 1].r_name) != 0)
					continue;
			if (strcmp(rules[i].r_filename,
				rules[i + 1].r_filename) == 0)
					continue;
			eat(rules[i].r_filename, rules[i].r_linenum);
			warning(_("same rule name in multiple files"));
			eat(rules[i + 1].r_filename, rules[i + 1].r_linenum);
			warning(_("same rule name in multiple files"));
			for (j = i + 2; j < nrules; ++j) {
				if (strcmp(rules[i].r_name,
					rules[j].r_name) != 0)
						break;
				if (strcmp(rules[i].r_filename,
					rules[j].r_filename) == 0)
						continue;
				if (strcmp(rules[i + 1].r_filename,
					rules[j].r_filename) == 0)
						continue;
				break;
			}
			i = j - 1;
		}
	}
	for (i = 0; i < nzones; ++i) {
		zp = &zones[i];
		zp->z_rules = NULL;
		zp->z_nrules = 0;
	}
	for (base = 0; base < nrules; base = out) {
		rp = &rules[base];
		for (out = base + 1; out < nrules; ++out)
			if (strcmp(rp->r_name, rules[out].r_name) != 0)
				break;
		for (i = 0; i < nzones; ++i) {
			zp = &zones[i];
			if (strcmp(zp->z_rule, rp->r_name) != 0)
				continue;
			zp->z_rules = rp;
			zp->z_nrules = out - base;
		}
	}
	for (i = 0; i < nzones; ++i) {
		zp = &zones[i];
		if (zp->z_nrules == 0) {
			/*
			** Maybe we have a local standard time offset.
			*/
			eat(zp->z_filename, zp->z_linenum);
			zp->z_save = getsave(zp->z_rule, &zp->z_isdst);
			/*
			** Note, though, that if there's no rule,
			** a '%s' in the format is a bad thing.
			*/
			if (zp->z_format_specifier == 's')
				error("%s", _("%s in ruleless zone"));
		}
	}
	if (errors)
		exit(EXIT_FAILURE);
}

static void
infile(const char *name)
{
	FILE *			fp;
	char **		fields;
	char *			cp;
	const struct lookup *	lp;
	int			nfields;
	bool			wantcont;
	lineno			num;
	char				buf[BUFSIZ];

	if (strcmp(name, "-") == 0) {
		name = _("standard input");
		fp = stdin;
	} else if ((fp = fopen(name, "r")) == NULL) {
		const char *e = strerror(errno);

		fprintf(stderr, _("%s: Can't open %s: %s\n"),
			progname, name, e);
		exit(EXIT_FAILURE);
	}
	wantcont = false;
	for (num = 1; ; ++num) {
		eat(name, num);
		if (fgets(buf, (int) sizeof buf, fp) != buf)
			break;
		cp = strchr(buf, '\n');
		if (cp == NULL) {
			error(_("line too long"));
			exit(EXIT_FAILURE);
		}
		*cp = '\0';
		fields = getfields(buf);
		nfields = 0;
		while (fields[nfields] != NULL) {
			static char	nada;

			if (strcmp(fields[nfields], "-") == 0)
				fields[nfields] = &nada;
			++nfields;
		}
		if (nfields == 0) {
			/* nothing to do */
		} else if (wantcont) {
			wantcont = inzcont(fields, nfields);
		} else {
			struct lookup const *line_codes
			  = name == leapsec ? leap_line_codes : zi_line_codes;
			lp = byword(fields[0], line_codes);
			if (lp == NULL)
				error(_("input line of unknown type"));
			else switch (lp->l_value) {
				case LC_RULE:
					inrule(fields, nfields);
					wantcont = false;
					break;
				case LC_ZONE:
					wantcont = inzone(fields, nfields);
					break;
				case LC_LINK:
					inlink(fields, nfields);
					wantcont = false;
					break;
				case LC_LEAP:
					inleap(fields, nfields);
					wantcont = false;
					break;
				case LC_EXPIRES:
					inexpires(fields, nfields);
					wantcont = false;
					break;
				default: UNREACHABLE();
			}
		}
		free(fields);
	}
	close_file(fp, NULL, filename, NULL);
	if (wantcont)
		error(_("expected continuation line not found"));
}

/*
** Convert a string of one of the forms
**	h	-h	hh:mm	-hh:mm	hh:mm:ss	-hh:mm:ss
** into a number of seconds.
** A null string maps to zero.
** Call error with errstring and return zero on errors.
*/

static zic_t
gethms(char const *string, char const *errstring)
{
	zic_t	hh;
	int sign, mm = 0, ss = 0;
	char hhx, mmx, ssx, xr = '0', xs;
	int tenths = 0;
	bool ok = true;

	if (string == NULL || *string == '\0')
		return 0;
	if (*string == '-') {
		sign = -1;
		++string;
	} else	sign = 1;
	switch (sscanf(string,
		       "%"SCNdZIC"%c%d%c%d%c%1d%*[0]%c%*[0123456789]%c",
		       &hh, &hhx, &mm, &mmx, &ss, &ssx, &tenths, &xr, &xs)) {
	  default: ok = false; break;
	  case 8:
	    ok = '0' <= xr && xr <= '9';
	    /* fallthrough */
	  case 7:
	    ok &= ssx == '.';
	    if (ok && noise)
	      warning(_("fractional seconds rejected by"
			" pre-2018 versions of zic"));
	    /* fallthrough */
	  case 5: ok &= mmx == ':'; /* fallthrough */
	  case 3: ok &= hhx == ':'; /* fallthrough */
	  case 1: break;
	}
	if (!ok) {
			error("%s", errstring);
			return 0;
	}
	if (hh < 0 ||
		mm < 0 || mm >= MINSPERHOUR ||
		ss < 0 || ss > SECSPERMIN) {
			error("%s", errstring);
			return 0;
	}
	if (ZIC_MAX / SECSPERHOUR < hh) {
		error(_("time overflow"));
		return 0;
	}
	ss += 5 + ((ss ^ 1) & (xr == '0')) <= tenths; /* Round to even.  */
	if (noise && (hh > HOURSPERDAY ||
		(hh == HOURSPERDAY && (mm != 0 || ss != 0))))
warning(_("values over 24 hours not handled by pre-2007 versions of zic"));
	return oadd(sign * hh * SECSPERHOUR,
		    sign * (mm * SECSPERMIN + ss));
}

static zic_t
getsave(char *field, bool *isdst)
{
  int dst = -1;
  zic_t save;
  size_t fieldlen = strlen(field);
  if (fieldlen != 0) {
    char *ep = field + fieldlen - 1;
    switch (*ep) {
      case 'd': dst = 1; *ep = '\0'; break;
      case 's': dst = 0; *ep = '\0'; break;
    }
  }
  save = gethms(field, _("invalid saved time"));
  *isdst = dst < 0 ? save != 0 : dst;
  return save;
}

static void
inrule(char **fields, int nfields)
{
	struct rule r;

	if (nfields != RULE_FIELDS) {
		error(_("wrong number of fields on Rule line"));
		return;
	}
	switch (*fields[RF_NAME]) {
	  case '\0':
	  case ' ': case '\f': case '\n': case '\r': case '\t': case '\v':
	  case '+': case '-':
	  case '0': case '1': case '2': case '3': case '4':
	  case '5': case '6': case '7': case '8': case '9':
		error(_("Invalid rule name \"%s\""), fields[RF_NAME]);
		return;
	}
	r.r_filename = filename;
	r.r_linenum = linenum;
	r.r_save = getsave(fields[RF_SAVE], &r.r_isdst);
	if (!rulesub(&r, fields[RF_LOYEAR], fields[RF_HIYEAR],
		     fields[RF_COMMAND], fields[RF_MONTH], fields[RF_DAY],
		     fields[RF_TOD]))
	  return;
	r.r_name = ecpyalloc(fields[RF_NAME]);
	r.r_abbrvar = ecpyalloc(fields[RF_ABBRVAR]);
	if (max_abbrvar_len < strlen(r.r_abbrvar))
		max_abbrvar_len = strlen(r.r_abbrvar);
	rules = growalloc(rules, sizeof *rules, nrules, &nrules_alloc);
	rules[nrules++] = r;
}

static bool
inzone(char **fields, int nfields)
{
	ptrdiff_t	i;

	if (nfields < ZONE_MINFIELDS || nfields > ZONE_MAXFIELDS) {
		error(_("wrong number of fields on Zone line"));
		return false;
	}
	if (lcltime != NULL && strcmp(fields[ZF_NAME], tzdefault) == 0) {
		error(
_("\"Zone %s\" line and -l option are mutually exclusive"),
			tzdefault);
		return false;
	}
	if (strcmp(fields[ZF_NAME], TZDEFRULES) == 0 && psxrules != NULL) {
		error(
_("\"Zone %s\" line and -p option are mutually exclusive"),
			TZDEFRULES);
		return false;
	}
	for (i = 0; i < nzones; ++i)
		if (zones[i].z_name != NULL &&
		    strcmp(zones[i].z_name, fields[ZF_NAME]) == 0) {
			error(_("duplicate zone name %s"
				" (file \"%s\", line %"PRIdMAX")"),
				fields[ZF_NAME],
				zones[i].z_filename,
				zones[i].z_linenum);
			return false;
		}
	return inzsub(fields, nfields, false);
}

static bool
inzcont(char **fields, int nfields)
{
	if (nfields < ZONEC_MINFIELDS || nfields > ZONEC_MAXFIELDS) {
		error(_("wrong number of fields on Zone continuation line"));
		return false;
	}
	return inzsub(fields, nfields, true);
}

static bool
inzsub(char **fields, int nfields, bool iscont)
{
	char *		cp;
	char *		cp1;
	struct zone	z;
	size_t format_len;
	int		i_stdoff, i_rule, i_format;
	int		i_untilyear, i_untilmonth;
	int		i_untilday, i_untiltime;
	bool		hasuntil;

	if (iscont) {
		i_stdoff = ZFC_STDOFF;
		i_rule = ZFC_RULE;
		i_format = ZFC_FORMAT;
		i_untilyear = ZFC_TILYEAR;
		i_untilmonth = ZFC_TILMONTH;
		i_untilday = ZFC_TILDAY;
		i_untiltime = ZFC_TILTIME;
	} else if (!namecheck(fields[ZF_NAME]))
		return false;
	else {
		i_stdoff = ZF_STDOFF;
		i_rule = ZF_RULE;
		i_format = ZF_FORMAT;
		i_untilyear = ZF_TILYEAR;
		i_untilmonth = ZF_TILMONTH;
		i_untilday = ZF_TILDAY;
		i_untiltime = ZF_TILTIME;
	}
	z.z_filename = filename;
	z.z_linenum = linenum;
	z.z_stdoff = gethms(fields[i_stdoff], _("invalid UT offset"));
	if ((cp = strchr(fields[i_format], '%')) != 0) {
		if ((*++cp != 's' && *cp != 'z') || strchr(cp, '%')
		    || strchr(fields[i_format], '/')) {
			error(_("invalid abbreviation format"));
			return false;
		}
	}
	z.z_format_specifier = cp ? *cp : '\0';
	format_len = strlen(fields[i_format]);
	if (max_format_len < format_len)
	  max_format_len = format_len;
	hasuntil = nfields > i_untilyear;
	if (hasuntil) {
		z.z_untilrule.r_filename = filename;
		z.z_untilrule.r_linenum = linenum;
		if (!rulesub(
			&z.z_untilrule,
			fields[i_untilyear],
			"only",
			"",
			(nfields > i_untilmonth) ?
			fields[i_untilmonth] : "Jan",
			(nfields > i_untilday) ? fields[i_untilday] : "1",
			(nfields > i_untiltime) ? fields[i_untiltime] : "0"))
		  return false;
		z.z_untiltime = rpytime(&z.z_untilrule,
			z.z_untilrule.r_loyear);
		if (iscont && nzones > 0 &&
			z.z_untiltime > min_time &&
			z.z_untiltime < max_time &&
			zones[nzones - 1].z_untiltime > min_time &&
			zones[nzones - 1].z_untiltime < max_time &&
			zones[nzones - 1].z_untiltime >= z.z_untiltime) {
				error(_(
"Zone continuation line end time is not after end time of previous line"
					));
				return false;
		}
	}
	z.z_name = iscont ? NULL : ecpyalloc(fields[ZF_NAME]);
	z.z_rule = ecpyalloc(fields[i_rule]);
	z.z_format = cp1 = ecpyalloc(fields[i_format]);
	if (z.z_format_specifier == 'z') {
	  cp1[cp - fields[i_format]] = 's';
	  if (noise)
	    warning(_("format '%s' not handled by pre-2015 versions of zic"),
		    fields[i_format]);
	}
	zones = growalloc(zones, sizeof *zones, nzones, &nzones_alloc);
	zones[nzones++] = z;
	/*
	** If there was an UNTIL field on this line,
	** there's more information about the zone on the next line.
	*/
	return hasuntil;
}

static zic_t
getleapdatetime(char **fields, int nfields, bool expire_line)
{
	const char *		cp;
	const struct lookup *	lp;
	zic_t			i, j;
	zic_t			year;
	int			month, day;
	zic_t			dayoff, tod;
	zic_t			t;
	char			xs;

	dayoff = 0;
	cp = fields[LP_YEAR];
	if (sscanf(cp, "%"SCNdZIC"%c", &year, &xs) != 1) {
		/*
		** Leapin' Lizards!
		*/
		error(_("invalid leaping year"));
		return -1;
	}
	if (!expire_line) {
	    if (!leapseen || leapmaxyear < year)
		leapmaxyear = year;
	    if (!leapseen || leapminyear > year)
		leapminyear = year;
	    leapseen = true;
	}
	j = EPOCH_YEAR;
	while (j != year) {
		if (year > j) {
			i = len_years[isleap(j)];
			++j;
		} else {
			--j;
			i = -len_years[isleap(j)];
		}
		dayoff = oadd(dayoff, i);
	}
	if ((lp = byword(fields[LP_MONTH], mon_names)) == NULL) {
		error(_("invalid month name"));
		return -1;
	}
	month = lp->l_value;
	j = TM_JANUARY;
	while (j != month) {
		i = len_months[isleap(year)][j];
		dayoff = oadd(dayoff, i);
		++j;
	}
	cp = fields[LP_DAY];
	if (sscanf(cp, "%d%c", &day, &xs) != 1 ||
		day <= 0 || day > len_months[isleap(year)][month]) {
			error(_("invalid day of month"));
			return -1;
	}
	dayoff = oadd(dayoff, day - 1);
	if (dayoff < min_time / SECSPERDAY) {
		error(_("time too small"));
		return -1;
	}
	if (dayoff > max_time / SECSPERDAY) {
		error(_("time too large"));
		return -1;
	}
	t = dayoff * SECSPERDAY;
	tod = gethms(fields[LP_TIME], _("invalid time of day"));
	t = tadd(t, tod);
	if (t < 0)
	  error(_("leap second precedes Epoch"));
	return t;
}

static void
inleap(char **fields, int nfields)
{
  if (nfields != LEAP_FIELDS)
    error(_("wrong number of fields on Leap line"));
  else {
    zic_t t = getleapdatetime(fields, nfields, false);
    if (0 <= t) {
      struct lookup const *lp = byword(fields[LP_ROLL], leap_types);
      if (!lp)
	error(_("invalid Rolling/Stationary field on Leap line"));
      else {
	int correction = 0;
	if (!fields[LP_CORR][0]) /* infile() turns "-" into "".  */
	  correction = -1;
	else if (strcmp(fields[LP_CORR], "+") == 0)
	  correction = 1;
	else
	  error(_("invalid CORRECTION field on Leap line"));
	if (correction)
	  leapadd(t, correction, lp->l_value);
      }
    }
  }
}

static void
inexpires(char **fields, int nfields)
{
  if (nfields != EXPIRES_FIELDS)
    error(_("wrong number of fields on Expires line"));
  else if (0 <= leapexpires)
    error(_("multiple Expires lines"));
  else
    leapexpires = getleapdatetime(fields, nfields, true);
}

static void
inlink(char **fields, int nfields)
{
	struct link	l;

	if (nfields != LINK_FIELDS) {
		error(_("wrong number of fields on Link line"));
		return;
	}
	if (*fields[LF_TARGET] == '\0') {
		error(_("blank TARGET field on Link line"));
		return;
	}
	if (! namecheck(fields[LF_LINKNAME]))
	  return;
	l.l_filename = filename;
	l.l_linenum = linenum;
	l.l_target = ecpyalloc(fields[LF_TARGET]);
	l.l_linkname = ecpyalloc(fields[LF_LINKNAME]);
	links = growalloc(links, sizeof *links, nlinks, &nlinks_alloc);
	links[nlinks++] = l;
}

static bool
rulesub(struct rule *rp, const char *loyearp, const char *hiyearp,
    const char *typep, const char *monthp, const char *dayp,
    const char *timep)
{
	const struct lookup *	lp;
	const char *		cp;
	char *			dp;
	char *			ep;
	char			xs;

	if ((lp = byword(monthp, mon_names)) == NULL) {
		error(_("invalid month name"));
		return false;
	}
	rp->r_month = lp->l_value;
	rp->r_todisstd = false;
	rp->r_todisut = false;
	dp = ecpyalloc(timep);
	if (*dp != '\0') {
		ep = dp + strlen(dp) - 1;
		switch (lowerit(*ep)) {
			case 's':	/* Standard */
				rp->r_todisstd = true;
				rp->r_todisut = false;
				*ep = '\0';
				break;
			case 'w':	/* Wall */
				rp->r_todisstd = false;
				rp->r_todisut = false;
				*ep = '\0';
				break;
			case 'g':	/* Greenwich */
			case 'u':	/* Universal */
			case 'z':	/* Zulu */
				rp->r_todisstd = true;
				rp->r_todisut = true;
				*ep = '\0';
				break;
		}
	}
	rp->r_tod = gethms(dp, _("invalid time of day"));
	free(dp);
	/*
	** Year work.
	*/
	cp = loyearp;
	lp = byword(cp, begin_years);
	rp->r_lowasnum = lp == NULL;
	if (!rp->r_lowasnum) switch (lp->l_value) {
		case YR_MINIMUM:
			rp->r_loyear = ZIC_MIN;
			break;
		case YR_MAXIMUM:
			rp->r_loyear = ZIC_MAX;
			break;
		default: UNREACHABLE();
	} else if (sscanf(cp, "%"SCNdZIC"%c", &rp->r_loyear, &xs) != 1) {
		error(_("invalid starting year"));
		return false;
	}
	cp = hiyearp;
	lp = byword(cp, end_years);
	rp->r_hiwasnum = lp == NULL;
	if (!rp->r_hiwasnum) switch (lp->l_value) {
		case YR_MINIMUM:
			rp->r_hiyear = ZIC_MIN;
			break;
		case YR_MAXIMUM:
			rp->r_hiyear = ZIC_MAX;
			break;
		case YR_ONLY:
			rp->r_hiyear = rp->r_loyear;
			break;
		default: UNREACHABLE();
	} else if (sscanf(cp, "%"SCNdZIC"%c", &rp->r_hiyear, &xs) != 1) {
		error(_("invalid ending year"));
		return false;
	}
	if (rp->r_loyear > rp->r_hiyear) {
		error(_("starting year greater than ending year"));
		return false;
	}
	if (*typep != '\0') {
		error(_("year type \"%s\" is unsupported; use \"-\" instead"),
			typep);
		return false;
	}
	/*
	** Day work.
	** Accept things such as:
	**	1
	**	lastSunday
	**	last-Sunday (undocumented; warn about this)
	**	Sun<=20
	**	Sun>=7
	*/
	dp = ecpyalloc(dayp);
	if ((lp = byword(dp, lasts)) != NULL) {
		rp->r_dycode = DC_DOWLEQ;
		rp->r_wday = lp->l_value;
		rp->r_dayofmonth = len_months[1][rp->r_month];
	} else {
		if ((ep = strchr(dp, '<')) != 0)
			rp->r_dycode = DC_DOWLEQ;
		else if ((ep = strchr(dp, '>')) != 0)
			rp->r_dycode = DC_DOWGEQ;
		else {
			ep = dp;
			rp->r_dycode = DC_DOM;
		}
		if (rp->r_dycode != DC_DOM) {
			*ep++ = 0;
			if (*ep++ != '=') {
				error(_("invalid day of month"));
				free(dp);
				return false;
			}
			if ((lp = byword(dp, wday_names)) == NULL) {
				error(_("invalid weekday name"));
				free(dp);
				return false;
			}
			rp->r_wday = lp->l_value;
		}
		if (sscanf(ep, "%d%c", &rp->r_dayofmonth, &xs) != 1 ||
			rp->r_dayofmonth <= 0 ||
			(rp->r_dayofmonth > len_months[1][rp->r_month])) {
				error(_("invalid day of month"));
				free(dp);
				return false;
		}
	}
	free(dp);
	return true;
}

static void
convert(uint_fast32_t val, char *buf)
{
	int	i;
	int	shift;
	unsigned char *const b = (unsigned char *) buf;

	for (i = 0, shift = 24; i < 4; ++i, shift -= 8)
		b[i] = (val >> shift) & 0xff;
}

static void
convert64(uint_fast64_t val, char *buf)
{
	int	i;
	int	shift;
	unsigned char *const b = (unsigned char *) buf;

	for (i = 0, shift = 56; i < 8; ++i, shift -= 8)
		b[i] = (val >> shift) & 0xff;
}

static void
puttzcode(const int_fast32_t val, FILE *const fp)
{
	char	buf[4];

	convert(val, buf);
	fwrite(buf, sizeof buf, (size_t) 1, fp);
}

static void
puttzcodepass(zic_t val, FILE *fp, int pass)
{
  if (pass == 1)
    puttzcode(val, fp);
  else {
	char	buf[8];

	convert64(val, buf);
	fwrite(buf, sizeof buf, (size_t) 1, fp);
    }
}

static int
atcomp(const void *avp, const void *bvp)
{
  struct attype const *ap = avp, *bp = bvp;
  zic_t a = ap->at, b = bp->at;
  return a < b ? -1 : a > b;
}

struct timerange {
  int defaulttype;
  ptrdiff_t base, count;
  int leapbase, leapcount;
  bool pretrans, leapexpiry;
};

static struct timerange
limitrange(struct timerange r, bool locut, zic_t lo, zic_t hi,
	   zic_t const *ats, unsigned char const *types)
{
  /* Omit ordinary transitions < LO.  */
  while (0 < r.count && ats[r.base] < lo) {
    r.defaulttype = types[r.base];
    r.count--;
    r.base++;
  }

  /* "-00" before any -r low cutoff.  */
  if (min_time < lo_time)
    r.defaulttype = unspecifiedtype;

  /* Omit as many initial leap seconds as possible, such that the
     first leap second in the truncated list is <= LO, and is a
     positive leap second if and only if it has a positive correction.
     This supports common TZif readers that assume that the first leap
     second is positive if and only if its correction is positive.  */
  while (1 < r.leapcount && trans[r.leapbase + 1] <= lo) {
    r.leapcount--;
    r.leapbase++;
  }
  while (0 < r.leapbase
	 && ((corr[r.leapbase - 1] < corr[r.leapbase])
	     != (0 < corr[r.leapbase]))) {
    r.leapcount++;
    r.leapbase--;
  }


  /* Omit ordinary and leap second transitions greater than HI + 1.  */
  if (hi < max_time) {
    while (0 < r.count && hi + 1 < ats[r.base + r.count - 1])
      r.count--;
    while (0 < r.leapcount && hi + 1 < trans[r.leapbase + r.leapcount - 1])
      r.leapcount--;
  }

  /* Determine whether to keep the last too-low transition if no
     transition is exactly at LO.  The kept transition will be output
     as a LO "transition"; see "Output a LO_TIME transition" below.
     This is needed when the output is truncated at the start, and is
     also useful when catering to buggy 32-bit clients that do not use
     time type 0 for timestamps before the first transition.  */
  r.pretrans = locut && r.base && ! (r.count && ats[r.base] == lo);

  /* Determine whether to append an expiration to the leap second table.  */
  r.leapexpiry = 0 <= leapexpires && leapexpires - 1 <= hi;

  return r;
}

static void
writezone(const char *const name, const char *const string, char version,
	int defaulttype)
{
	FILE *			fp;
	ptrdiff_t		i, j;
	int			pass;
	zic_t one = 1;
	zic_t y2038_boundary = one << 31;
	ptrdiff_t nats = timecnt + WORK_AROUND_QTBUG_53071;
	char *tempname = NULL;
	char const *outname = name;

	/* Allocate the ATS and TYPES arrays via a single malloc,
	   as this is a bit faster.  */
	zic_t *ats = zic_malloc(align_to(size_product(nats, sizeof *ats + 1),
				_Alignof(zic_t)));
	void *typesptr = ats + nats;
	unsigned char *types = typesptr;
	struct timerange rangeall, range32, range64;

	/*
	** Sort.
	*/
	if (timecnt > 1)
		qsort(attypes, (size_t) timecnt, sizeof *attypes, atcomp);
	/*
	** Optimize.
	*/
	{
		ptrdiff_t fromi, toi;

		toi = 0;
		fromi = 0;
		for ( ; fromi < timecnt; ++fromi) {
			if (toi != 0
			    && ((attypes[fromi].at
				 + utoffs[attypes[toi - 1].type])
				<= (attypes[toi - 1].at
				    + utoffs[toi == 1 ? 0
					     : attypes[toi - 2].type]))) {
					attypes[toi - 1].type =
						attypes[fromi].type;
					continue;
			}
			if (toi == 0
			    || attypes[fromi].dontmerge
			    || (utoffs[attypes[toi - 1].type]
				!= utoffs[attypes[fromi].type])
			    || (isdsts[attypes[toi - 1].type]
				!= isdsts[attypes[fromi].type])
			    || (desigidx[attypes[toi - 1].type]
				!= desigidx[attypes[fromi].type]))
					attypes[toi++] = attypes[fromi];
		}
		timecnt = toi;
	}

	if (noise && timecnt > 1200) {
	  if (timecnt > TZ_MAX_TIMES)
		warning(_("reference clients mishandle"
			  " more than %d transition times"),
			TZ_MAX_TIMES);
	  else
		warning(_("pre-2014 clients may mishandle"
			  " more than 1200 transition times"));
	}
	/*
	** Transfer.
	*/
	for (i = 0; i < timecnt; ++i) {
		ats[i] = attypes[i].at;
		types[i] = attypes[i].type;
	}

	/*
	** Correct for leap seconds.
	*/
	for (i = 0; i < timecnt; ++i) {
		j = leapcnt;
		while (--j >= 0)
			if (ats[i] > trans[j] - corr[j]) {
				ats[i] = tadd(ats[i], corr[j]);
				break;
			}
	}

	/* Work around QTBUG-53071 for timestamps less than y2038_boundary - 1,
	   by inserting a no-op transition at time y2038_boundary - 1.
	   This works only for timestamps before the boundary, which
	   should be good enough in practice as QTBUG-53071 should be
	   long-dead by 2038.  Do this after correcting for leap
	   seconds, as the idea is to insert a transition just before
	   32-bit time_t rolls around, and this occurs at a slightly
	   different moment if transitions are leap-second corrected.  */
	if (WORK_AROUND_QTBUG_53071 && timecnt != 0 && want_bloat()
	    && ats[timecnt - 1] < y2038_boundary - 1 && strchr(string, '<')) {
	  ats[timecnt] = y2038_boundary - 1;
	  types[timecnt] = types[timecnt - 1];
	  timecnt++;
	}

	rangeall.defaulttype = defaulttype;
	rangeall.base = rangeall.leapbase = 0;
	rangeall.count = timecnt;
	rangeall.leapcount = leapcnt;
	rangeall.pretrans = rangeall.leapexpiry = false;
	range64 = limitrange(rangeall, min_time < lo_time,
			     lo_time, hi_time, ats, types);
	range32 = limitrange(range64, true,
			     INT32_MIN, INT32_MAX, ats, types);

	/* TZif version 4 is needed if a no-op transition is appended to
	   indicate the expiration of the leap second table, or if the first
	   leap second transition is not to a +1 or -1 correction.  */
	for (pass = 1; pass <= 2; pass++) {
	  struct timerange const *r = pass == 1 ? &range32 : &range64;
	  if (pass == 1 && !want_bloat())
	    continue;
	  if (r->leapexpiry) {
	    if (noise)
	      warning(_("%s: pre-2021b clients may mishandle"
			" leap second expiry"),
		      name);
	    version = '4';
	  }
	  if (0 < r->leapcount
	      && corr[r->leapbase] != 1 && corr[r->leapbase] != -1) {
	    if (noise)
	      warning(_("%s: pre-2021b clients may mishandle"
			" leap second table truncation"),
		      name);
	    version = '4';
	  }
	  if (version == '4')
	    break;
 	}

	fp = open_outfile(&outname, &tempname);

	for (pass = 1; pass <= 2; ++pass) {
		ptrdiff_t	thistimei, thistimecnt, thistimelim;
		int	thisleapi, thisleapcnt, thisleaplim;
		struct tzhead tzh;
		int thisdefaulttype;
		bool hicut, pretrans, thisleapexpiry;
		zic_t lo;
		int old0;
		char		omittype[TZ_MAX_TYPES];
		int		typemap[TZ_MAX_TYPES];
		int		thistypecnt, stdcnt, utcnt;
		char		thischars[TZ_MAX_CHARS];
		int		thischarcnt;
		bool		toomanytimes;
		int		indmap[TZ_MAX_CHARS];

		if (pass == 1) {
			/* Arguably the default time type in the 32-bit data
			   should be range32.defaulttype, which is suited for
			   timestamps just before INT32_MIN.  However, zic
			   traditionally used the time type of the indefinite
			   past instead.  Internet RFC 8532 says readers should
			   ignore 32-bit data, so this discrepancy matters only
			   to obsolete readers where the traditional type might
			   be more appropriate even if it's "wrong".  So, use
			   the historical zic value, unless -r specifies a low
			   cutoff that excludes some 32-bit timestamps.  */
			thisdefaulttype = (lo_time <= INT32_MIN
					   ? range64.defaulttype
					   : range32.defaulttype);

			thistimei = range32.base;
			thistimecnt = range32.count;
			toomanytimes = thistimecnt >> 31 >> 1 != 0;
			thisleapi = range32.leapbase;
			thisleapcnt = range32.leapcount;
			pretrans = range32.pretrans;
			thisleapexpiry = range32.leapexpiry;
			hicut = hi_time < INT32_MAX;
		} else {
			thisdefaulttype = range64.defaulttype;
			thistimei = range64.base;
			thistimecnt = range64.count;
			toomanytimes = thistimecnt >> 31 >> 31 >> 2 != 0;
			thisleapi = range64.leapbase;
			thisleapcnt = range64.leapcount;
			pretrans = range64.pretrans;
			thisleapexpiry = range64.leapexpiry;
			hicut = hi_time < max_time;
		}
		if (toomanytimes)
		  error(_("too many transition times"));

		thistimelim = thistimei + thistimecnt;
		memset(omittype, true, typecnt);
		omittype[thisdefaulttype] = false;
		for (i = thistimei - pretrans; i < thistimelim; i++)
		  omittype[types[i]] = false;
		if (hicut)
		  omittype[unspecifiedtype] = false;

		/* Reorder types to make THISDEFAULTTYPE type 0.
		   Use TYPEMAP to swap OLD0 and THISDEFAULTTYPE so that
		   THISDEFAULTTYPE appears as type 0 in the output instead
		   of OLD0.  TYPEMAP also omits unused types.  */
		old0 = strlen(omittype);

#ifndef LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH
		/*
		** For some pre-2011 systems: if the last-to-be-written
		** standard (or daylight) type has an offset different from the
		** most recently used offset,
		** append an (unused) copy of the most recently used type
		** (to help get global "altzone" and "timezone" variables
		** set correctly).
		*/
		if (want_bloat()) {
			int	mrudst, mrustd, hidst, histd, type;

			hidst = histd = mrudst = mrustd = -1;
			for (i = thistimei - pretrans; i < thistimelim; ++i)
				if (isdsts[types[i]])
					mrudst = types[i];
				else	mrustd = types[i];
			for (i = old0; i < typecnt; i++) {
			  int h = (i == old0 ? thisdefaulttype
				   : i == thisdefaulttype ? old0 : i);
			  if (!omittype[h]) {
			    if (isdsts[h])
			      hidst = i;
			    else
			      histd = i;
			  }
			}
			if (hidst >= 0 && mrudst >= 0 && hidst != mrudst &&
				utoffs[hidst] != utoffs[mrudst]) {
					isdsts[mrudst] = -1;
					type = addtype(utoffs[mrudst],
						&chars[desigidx[mrudst]],
						true,
						ttisstds[mrudst],
						ttisuts[mrudst]);
					isdsts[mrudst] = 1;
					omittype[type] = false;
			}
			if (histd >= 0 && mrustd >= 0 && histd != mrustd &&
				utoffs[histd] != utoffs[mrustd]) {
					isdsts[mrustd] = -1;
					type = addtype(utoffs[mrustd],
						&chars[desigidx[mrustd]],
						false,
						ttisstds[mrustd],
						ttisuts[mrustd]);
					isdsts[mrustd] = 0;
					omittype[type] = false;
			}
		}
#endif /* !defined LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH */
 		thistypecnt = 0;
		for (i = old0; i < typecnt; i++)
		  if (!omittype[i])
		    typemap[i == old0 ? thisdefaulttype
			    : i == thisdefaulttype ? old0 : i]
		      = thistypecnt++;

		for (i = 0; i < (int)(sizeof indmap / sizeof indmap[0]); ++i)
			indmap[i] = -1;
		thischarcnt = stdcnt = utcnt = 0;
		for (i = old0; i < typecnt; i++) {
			char *	thisabbr;

			if (omittype[i])
				continue;
			if (ttisstds[i])
			  stdcnt = thistypecnt;
			if (ttisuts[i])
			  utcnt = thistypecnt;
			if (indmap[desigidx[i]] >= 0)
				continue;
			thisabbr = &chars[desigidx[i]];
			for (j = 0; j < thischarcnt; ++j)
				if (strcmp(&thischars[j], thisabbr) == 0)
					break;
			if (j == thischarcnt) {
				strcpy(&thischars[thischarcnt], thisabbr);
				thischarcnt += strlen(thisabbr) + 1;
			}
			indmap[desigidx[i]] = j;
		}
		if (pass == 1 && !want_bloat()) {
		  pretrans = hicut = thisleapexpiry = false;
		  thistimecnt = thisleapcnt = 0;
		  thistypecnt = thischarcnt = 1;
		}
#define DO(field)	fwrite(tzh.field, sizeof tzh.field, (size_t) 1, fp)
		memset(&tzh, 0, sizeof(tzh));
		memcpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
		tzh.tzh_version[0] = version;
		convert(utcnt, tzh.tzh_ttisutcnt);
		convert(stdcnt, tzh.tzh_ttisstdcnt);
		convert(thisleapcnt + thisleapexpiry, tzh.tzh_leapcnt);
		convert(pretrans + thistimecnt + hicut, tzh.tzh_timecnt);
		convert(thistypecnt, tzh.tzh_typecnt);
		convert(thischarcnt, tzh.tzh_charcnt);
		DO(tzh_magic);
		DO(tzh_version);
		DO(tzh_reserved);
		DO(tzh_ttisutcnt);
		DO(tzh_ttisstdcnt);
		DO(tzh_leapcnt);
		DO(tzh_timecnt);
		DO(tzh_typecnt);
		DO(tzh_charcnt);
#undef DO
		if (pass == 1 && !want_bloat()) {
		  /* Output a minimal data block with just one time type.  */
		  puttzcode(0, fp);	/* utoff */
		  putc(0, fp);		/* dst */
		  putc(0, fp);		/* index of abbreviation */
		  putc(0, fp);		/* empty-string abbreviation */
		  continue;
		}

		/* Output a LO_TIME transition if needed; see limitrange.
		   But do not go below the minimum representable value
		   for this pass.  */
		lo = pass == 1 && lo_time < INT32_MIN ? INT32_MIN : lo_time;

		if (pretrans)
		  puttzcodepass(lo, fp, pass);
		for (i = thistimei; i < thistimelim; ++i) {
		  puttzcodepass(ats[i], fp, pass);
		}
		if (hicut)
		  puttzcodepass(hi_time + 1, fp, pass);
		for (i = thistimei - pretrans; i < thistimelim; ++i)
		  putc(typemap[types[i]], fp);
		if (hicut)
		  putc(typemap[unspecifiedtype], fp);

		for (i = old0; i < typecnt; i++) {
		  int h = (i == old0 ? thisdefaulttype
			   : i == thisdefaulttype ? old0 : i);
		  if (!omittype[h]) {
		    puttzcode(utoffs[h], fp);
		    putc(isdsts[h], fp);
		    putc(indmap[desigidx[h]], fp);
		  }
		}
		if (thischarcnt != 0)
			fwrite(thischars, sizeof thischars[0],
				(size_t) thischarcnt, fp);
		thisleaplim = thisleapi + thisleapcnt;
		for (i = thisleapi; i < thisleaplim; ++i) {
			zic_t	todo;

			if (roll[i]) {
				if (timecnt == 0 || trans[i] < ats[0]) {
					j = 0;
					while (isdsts[j])
						if (++j >= typecnt) {
							j = 0;
							break;
						}
				} else {
					j = 1;
					while (j < timecnt &&
						trans[i] >= ats[j])
							++j;
					j = types[j - 1];
				}
				todo = tadd(trans[i], -utoffs[j]);
			} else	todo = trans[i];
			puttzcodepass(todo, fp, pass);
			puttzcode(corr[i], fp);
		}
		if (thisleapexpiry) {
		  /* Append a no-op leap correction indicating when the leap
		     second table expires.  Although this does not conform to
		     Internet RFC 8536, most clients seem to accept this and
		     the plan is to amend the RFC to allow this in version 4
		     TZif files.  */
		  puttzcodepass(leapexpires, fp, pass);
		  puttzcode(thisleaplim ? corr[thisleaplim - 1] : 0, fp);
		}
		if (stdcnt != 0)
		  for (i = old0; i < typecnt; i++)
			if (!omittype[i])
				putc(ttisstds[i], fp);
		if (utcnt != 0)
		  for (i = old0; i < typecnt; i++)
			if (!omittype[i])
				putc(ttisuts[i], fp);
	}
	fprintf(fp, "\n%s\n", string);
	close_file(fp, directory, name, tempname);
	rename_dest(tempname, name);
	free(ats);
}

static char const *
abbroffset(char *buf, zic_t offset)
{
	char sign = '+';
	int seconds, minutes;

	if (offset < 0) {
		offset = -offset;
		sign = '-';
	}

	seconds = offset % SECSPERMIN;
	offset /= SECSPERMIN;
	minutes = offset % MINSPERHOUR;
	offset /= MINSPERHOUR;
	if (100 <= offset) {
		error(_("%%z UT offset magnitude exceeds 99:59:59"));
		return "%z";
	} else {
		char *p = buf;
		*p++ = sign;
		*p++ = '0' + offset / 10;
		*p++ = '0' + offset % 10;
		if (minutes | seconds) {
			*p++ = '0' + minutes / 10;
			*p++ = '0' + minutes % 10;
			if (seconds) {
				*p++ = '0' + seconds / 10;
				*p++ = '0' + seconds % 10;
			}
		}
		*p = '\0';
		return buf;
	}
}

static size_t
doabbr(char *abbr, size_t abbrlen, struct zone const *zp, const char *letters,
    bool isdst, zic_t save, bool doquotes)
{
	char *	cp;
	char *	slashp;
	size_t	len;
	char const *format = zp->z_format;

	slashp = strchr(format, '/');
	if (slashp == NULL) {
		char letterbuf[PERCENT_Z_LEN_BOUND + 1];
		if (zp->z_format_specifier == 'z')
			letters = abbroffset(letterbuf, zp->z_stdoff + save);
		else if (!letters)
			letters = "%s";
		snprintf(abbr, abbrlen, format, letters);
	} else if (isdst) {
		strlcpy(abbr, slashp + 1, abbrlen);
	} else {
		memcpy(abbr, format, slashp - format);
		abbr[slashp - format] = '\0';
	}
	len = strlen(abbr);
	if (!doquotes)
		return len;
	for (cp = abbr; is_alpha(*cp); cp++)
		continue;
	if (len > 0 && *cp == '\0')
		return len;
	abbr[len + 2] = '\0';
	abbr[len + 1] = '>';
	memmove(abbr + 1, abbr, len);
	abbr[0] = '<';
	return len + 2;
}

static void
updateminmax(const zic_t x)
{
	if (min_year > x)
		min_year = x;
	if (max_year < x)
		max_year = x;
}

static int
stringoffset(char *result, int resultlen, zic_t offset)
{
	int	hours;
	int	minutes;
	int	seconds;
	bool negative = offset < 0;
	int len = negative;

	if (negative) {
		offset = -offset;
		result[0] = '-';
	}
	seconds = offset % SECSPERMIN;
	offset /= SECSPERMIN;
	minutes = offset % MINSPERHOUR;
	offset /= MINSPERHOUR;
	hours = offset;
	if (hours >= HOURSPERDAY * DAYSPERWEEK) {
		result[0] = '\0';
		return 0;
	}
	len += snprintf(result + len, resultlen - len, "%d", hours);
	if (minutes != 0 || seconds != 0) {
		len += snprintf(result + len, resultlen - len,
		    ":%02d", minutes);
		if (seconds != 0)
			len += snprintf(result + len, resultlen - len,
			    ":%02d", seconds);
	}
	return len;
}

static int
stringrule(char *result, int resultlen, struct rule *const rp, zic_t save, const zic_t stdoff)
{
	zic_t	tod = rp->r_tod;
	int	compat = 0, len = 0;

	if (rp->r_dycode == DC_DOM) {
		int	month, total;

		if (rp->r_dayofmonth == 29 && rp->r_month == TM_FEBRUARY)
			return -1;
		total = 0;
		for (month = 0; month < rp->r_month; ++month)
			total += len_months[0][month];
		/* Omit the "J" in Jan and Feb, as that's shorter.  */
		if (rp->r_month <= 1)
		  len += snprintf(result + len, resultlen - len, "%d", total + rp->r_dayofmonth - 1);
		else
		  len += snprintf(result + len, resultlen - len, "J%d", total + rp->r_dayofmonth);
	} else {
		int	week;
		int	wday = rp->r_wday;
		int	wdayoff;

		if (rp->r_dycode == DC_DOWGEQ) {
			wdayoff = (rp->r_dayofmonth - 1) % DAYSPERWEEK;
			if (wdayoff)
				compat = 2013;
			wday -= wdayoff;
			tod += wdayoff * SECSPERDAY;
			week = 1 + (rp->r_dayofmonth - 1) / DAYSPERWEEK;
		} else if (rp->r_dycode == DC_DOWLEQ) {
			if (rp->r_dayofmonth == len_months[1][rp->r_month])
				week = 5;
			else {
				wdayoff = rp->r_dayofmonth % DAYSPERWEEK;
				if (wdayoff)
					compat = 2013;
				wday -= wdayoff;
				tod += wdayoff * SECSPERDAY;
				week = rp->r_dayofmonth / DAYSPERWEEK;
			}
		} else	return -1;	/* "cannot happen" */
		if (wday < 0)
			wday += DAYSPERWEEK;
		len += snprintf(result + len, resultlen - len, "M%d.%d.%d",
				  rp->r_month + 1, week, wday);
	}
	if (rp->r_todisut)
	  tod += stdoff;
	if (rp->r_todisstd && !rp->r_isdst)
	  tod += save;
	if (tod != 2 * SECSPERMIN * MINSPERHOUR) {
		if (len + 1 < resultlen)
		    result[len++] = '/';
		if (! stringoffset(result + len, resultlen - len, tod))
			return -1;
		if (tod < 0) {
			if (compat < 2013)
				compat = 2013;
		} else if (SECSPERDAY <= tod) {
			if (compat < 1994)
				compat = 1994;
		}
	}
	return compat;
}

static int
rule_cmp(struct rule const *a, struct rule const *b)
{
	if (!a)
		return -!!b;
	if (!b)
		return 1;
	if (a->r_hiyear != b->r_hiyear)
		return a->r_hiyear < b->r_hiyear ? -1 : 1;
	if (a->r_hiyear == ZIC_MAX)
		return 0;
	if (a->r_month - b->r_month != 0)
		return a->r_month - b->r_month;
	return a->r_dayofmonth - b->r_dayofmonth;
}

static int
stringzone(char *result, int resultlen, const struct zone *const zpfirst,
    const int zonecount)
{
	const struct zone *	zp;
	struct rule *		rp;
	struct rule *		stdrp;
	struct rule *		dstrp;
	ptrdiff_t	i;
	int			compat = 0;
	int			c;
	size_t			len;
	int			offsetlen;
	struct rule		stdr, dstr;
	int dstcmp;
	struct rule *lastrp[2] = { NULL, NULL };
	struct zone zstr[2];
	struct zone const *stdzp;
	struct zone const *dstzp;

	result[0] = '\0';

	/* Internet RFC 8536 section 5.1 says to use an empty TZ string if
	   future timestamps are truncated.  */
	if (hi_time < max_time)
	  return -1;

	zp = zpfirst + zonecount - 1;
	for (i = 0; i < zp->z_nrules; ++i) {
		struct rule **last;
		int cmp;
		rp = &zp->z_rules[i];
		last = &lastrp[rp->r_isdst];
		cmp = rule_cmp(*last, rp);
		if (cmp < 0)
		  *last = rp;
		else if (cmp == 0)
		  return -1;
	}
	stdrp = lastrp[false];
	dstrp = lastrp[true];
	dstcmp = zp->z_nrules ? rule_cmp(dstrp, stdrp) : zp->z_isdst ? 1 : -1;
	stdzp = dstzp = zp;

	if (dstcmp < 0) {
	  /* Standard time all year.  */
	  dstrp = NULL;
	} else if (0 < dstcmp) {
	  /* DST all year.  Use an abbreviation like
	     "XXX3EDT4,0/0,J365/23" for EDT (-04) all year.  */
	  zic_t save = dstrp ? dstrp->r_save : zp->z_save;
	  if (0 <= save)
	    {
	      /* Positive DST, the typical case for all-year DST.
		 Fake a timezone with negative DST.  */
	      stdzp = &zstr[0];
	      dstzp = &zstr[1];
	      zstr[0].z_stdoff = zp->z_stdoff + 2 * save;
	      zstr[0].z_format = "XXX";  /* Any 3 letters will do.  */
	      zstr[0].z_format_specifier = 0;
	      zstr[1].z_stdoff = zstr[0].z_stdoff;
	      zstr[1].z_format = zp->z_format;
	      zstr[1].z_format_specifier = zp->z_format_specifier;
	    }
	  dstr.r_month = TM_JANUARY;
	  dstr.r_dycode = DC_DOM;
	  dstr.r_dayofmonth = 1;
	  dstr.r_tod = 0;
	  dstr.r_todisstd = dstr.r_todisut = false;
	  dstr.r_isdst = true;
	  dstr.r_save = save < 0 ? save : -save;
	  dstr.r_abbrvar = dstrp ? dstrp->r_abbrvar : NULL;
	  stdr.r_month = TM_DECEMBER;
	  stdr.r_dycode = DC_DOM;
	  stdr.r_dayofmonth = 31;
	  stdr.r_tod = SECSPERDAY + dstr.r_save;
	  stdr.r_todisstd = stdr.r_todisut = false;
	  stdr.r_isdst = false;
	  stdr.r_save = 0;
	  stdr.r_abbrvar = save < 0 && stdrp ? stdrp->r_abbrvar : NULL;
	  dstrp = &dstr;
	  stdrp = &stdr;
	}
	len = doabbr(result, resultlen, stdzp, stdrp ? stdrp->r_abbrvar : NULL,
		     false, 0, true);
	offsetlen = stringoffset(result + len, resultlen - len,
	    -stdzp->z_stdoff);
	if (! offsetlen) {
		result[0] = '\0';
		return -1;
	}
	len += offsetlen;
	if (dstrp == NULL)
		return compat;
	len += doabbr(result + len, resultlen - len, dstzp, dstrp->r_abbrvar,
		      dstrp->r_isdst, dstrp->r_save, true);
	if (dstrp->r_save != SECSPERMIN * MINSPERHOUR) {
		offsetlen = stringoffset(result + len, resultlen - len,
				   - (dstzp->z_stdoff + dstrp->r_save));
		if (! offsetlen) {
			result[0] = '\0';
			return -1;
		}
		len += offsetlen;
	}
	result[len++] = ',';
	c = stringrule(result + len, resultlen - len, dstrp, dstrp->r_save, stdzp->z_stdoff);
	if (c < 0) {
		result[0] = '\0';
		return -1;
	}
	if (compat < c)
		compat = c;
	len += strlen(result + len);
	result[len++] = ',';
	c = stringrule(result + len, resultlen - len, stdrp, dstrp->r_save, stdzp->z_stdoff);
	if (c < 0) {
		result[0] = '\0';
		return -1;
	}
	if (compat < c)
		compat = c;
	return compat;
}

static void
outzone(const struct zone *zpfirst, ptrdiff_t zonecount)
{
	const struct zone *	zp;
	struct rule *		rp;
	ptrdiff_t		i, j;
	bool			usestart, useuntil;
	zic_t			starttime, untiltime;
	zic_t			stdoff;
	zic_t			save;
	zic_t			year;
	zic_t			startoff;
	bool			startttisstd;
	bool			startttisut;
	int			type;
	char *			startbuf;
	char *			ab;
	char *			envvar;
	size_t			max_abbr_len;
	size_t			max_envvar_len;
	bool			prodstic; /* all rules are min to max */
	int			compat;
	bool			do_extend;
	char			version;
	ptrdiff_t lastatmax = -1;
	zic_t one = 1;
	zic_t y2038_boundary = one << 31;
	zic_t max_year0;
	int defaulttype = -1;

	check_for_signal();

	max_abbr_len = 2 + max_format_len + max_abbrvar_len;
	max_envvar_len = 2 * max_abbr_len + 5 * 9;
	startbuf = zic_malloc(max_abbr_len + 1);
	ab = zic_malloc(max_abbr_len + 1);
	envvar = zic_malloc(max_envvar_len + 1);
	INITIALIZE(untiltime);
	INITIALIZE(starttime);
	/*
	** Now. . .finally. . .generate some useful data!
	*/
	timecnt = 0;
	typecnt = 0;
	charcnt = 0;
	prodstic = zonecount == 1;
	/*
	** Thanks to Earl Chew
	** for noting the need to unconditionally initialize startttisstd.
	*/
	startttisstd = false;
	startttisut = false;
	min_year = max_year = EPOCH_YEAR;
	if (leapseen) {
		updateminmax(leapminyear);
		updateminmax(leapmaxyear + (leapmaxyear < ZIC_MAX));
	}
	for (i = 0; i < zonecount; ++i) {
		zp = &zpfirst[i];
		if (i < zonecount - 1)
			updateminmax(zp->z_untilrule.r_loyear);
		for (j = 0; j < zp->z_nrules; ++j) {
			rp = &zp->z_rules[j];
			if (rp->r_lowasnum)
				updateminmax(rp->r_loyear);
			if (rp->r_hiwasnum)
				updateminmax(rp->r_hiyear);
			if (rp->r_lowasnum || rp->r_hiwasnum)
				prodstic = false;
		}
	}
	/*
	** Generate lots of data if a rule can't cover all future times.
	*/
	compat = stringzone(envvar, max_envvar_len + 1, zpfirst, zonecount);
	version = compat < 2013 ? '2' : '3';
	do_extend = compat < 0;
	if (noise) {
		if (!*envvar)
			warning("%s %s",
				_("no POSIX environment variable for zone"),
				zpfirst->z_name);
		else if (compat != 0) {
			/* Circa-COMPAT clients, and earlier clients, might
			   not work for this zone when given dates before
			   1970 or after 2038.  */
			warning(_("%s: pre-%d clients may mishandle"
				  " distant timestamps"),
				zpfirst->z_name, compat);
		}
	}
	if (do_extend) {
		/*
		** Search through a couple of extra years past the obvious
		** 400, to avoid edge cases.  For example, suppose a non-POSIX
		** rule applies from 2012 onwards and has transitions in March
		** and September, plus some one-off transitions in November
		** 2013.  If zic looked only at the last 400 years, it would
		** set max_year=2413, with the intent that the 400 years 2014
		** through 2413 will be repeated.  The last transition listed
		** in the tzfile would be in 2413-09, less than 400 years
		** after the last one-off transition in 2013-11.  Two years
		** might be overkill, but with the kind of edge cases
		** available we're not sure that one year would suffice.
		*/
		enum { years_of_observations = YEARSPERREPEAT + 2 };

		if (min_year >= ZIC_MIN + years_of_observations)
			min_year -= years_of_observations;
		else	min_year = ZIC_MIN;
		if (max_year <= ZIC_MAX - years_of_observations)
			max_year += years_of_observations;
		else	max_year = ZIC_MAX;
		/*
		** Regardless of any of the above,
		** for a "proDSTic" zone which specifies that its rules
		** always have and always will be in effect,
		** we only need one cycle to define the zone.
		*/
		if (prodstic) {
			min_year = 1900;
			max_year = min_year + years_of_observations;
		}
	}
	max_year0 = max_year;
	if (want_bloat()) {
	  /* For the benefit of older systems,
	     generate data from 1900 through 2038.  */
	  if (min_year > 1900)
		min_year = 1900;
	  if (max_year < 2038)
		max_year = 2038;
	}

	if (min_time < lo_time || hi_time < max_time)
	  unspecifiedtype = addtype(0, "-00", false, false, false);

	for (i = 0; i < zonecount; ++i) {
		struct rule *prevrp = NULL;
		zic_t prevktime;
		INITIALIZE(prevktime);
		/*
		** A guess that may well be corrected later.
		*/
		save = 0;
		zp = &zpfirst[i];
		usestart = i > 0 && (zp - 1)->z_untiltime > min_time;
		useuntil = i < (zonecount - 1);
		if (useuntil && zp->z_untiltime <= min_time)
			continue;
		stdoff = zp->z_stdoff;
		eat(zp->z_filename, zp->z_linenum);
		*startbuf = '\0';
		startoff = zp->z_stdoff;
		if (zp->z_nrules == 0) {
			save = zp->z_save;
			doabbr(startbuf, max_abbr_len + 1,
			    zp, NULL, zp->z_isdst, save, false);
			type = addtype(oadd(zp->z_stdoff, save),
				startbuf, zp->z_isdst, startttisstd,
				startttisut);
			if (usestart) {
				addtt(starttime, type);
				usestart = false;
			} else
				defaulttype = type;
		} else for (year = min_year; year <= max_year; ++year) {
			if (useuntil && year > zp->z_untilrule.r_hiyear)
				break;
			/*
			** Mark which rules to do in the current year.
			** For those to do, calculate rpytime(rp, year);
			** The former TYPE field was also considered here.
			*/
			for (j = 0; j < zp->z_nrules; ++j) {
				rp = &zp->z_rules[j];
				eats(zp->z_filename, zp->z_linenum,
					rp->r_filename, rp->r_linenum);
				rp->r_todo = year >= rp->r_loyear &&
						year <= rp->r_hiyear;
				if (rp->r_todo) {
					rp->r_temp = rpytime(rp, year);
					rp->r_todo
					  = (rp->r_temp < y2038_boundary
					     || year <= max_year0);
				}
			}
			for ( ; ; ) {
				ptrdiff_t	k;
				zic_t	jtime, ktime;
				zic_t	offset;

				INITIALIZE(ktime);
				if (useuntil) {
					/*
					** Turn untiltime into UT
					** assuming the current stdoff and
					** save values.
					*/
					untiltime = zp->z_untiltime;
					if (!zp->z_untilrule.r_todisut)
						untiltime = tadd(untiltime,
								 -stdoff);
					if (!zp->z_untilrule.r_todisstd)
						untiltime = tadd(untiltime,
								 -save);
				}
				/*
				** Find the rule (of those to do, if any)
				** that takes effect earliest in the year.
				*/
				k = -1;
				for (j = 0; j < zp->z_nrules; ++j) {
					rp = &zp->z_rules[j];
					if (!rp->r_todo)
						continue;
					eats(zp->z_filename, zp->z_linenum,
						rp->r_filename, rp->r_linenum);
					offset = rp->r_todisut ? 0 : stdoff;
					if (!rp->r_todisstd)
						offset = oadd(offset, save);
					jtime = rp->r_temp;
					if (jtime == min_time ||
						jtime == max_time)
							continue;
					jtime = tadd(jtime, -offset);
					if (k < 0 || jtime < ktime) {
						k = j;
						ktime = jtime;
					} else if (jtime == ktime) {
					  char const *dup_rules_msg =
					    _("two rules for same instant");
					  eats(zp->z_filename, zp->z_linenum,
					       rp->r_filename, rp->r_linenum);
					  warning("%s", dup_rules_msg);
					  rp = &zp->z_rules[k];
					  eats(zp->z_filename, zp->z_linenum,
					       rp->r_filename, rp->r_linenum);
					  error("%s", dup_rules_msg);
					}
				}
				if (k < 0)
					break;	/* go on to next year */
				rp = &zp->z_rules[k];
				rp->r_todo = false;
				if (useuntil && ktime >= untiltime)
					break;
				save = rp->r_save;
				if (usestart && ktime == starttime)
					usestart = false;
				if (usestart) {
					if (ktime < starttime) {
						startoff = oadd(zp->z_stdoff,
								save);
						doabbr(startbuf,
							max_abbr_len + 1,
							zp,
							rp->r_abbrvar,
							rp->r_isdst,
							rp->r_save,
							false);
						continue;
					}
					if (*startbuf == '\0'
					    && startoff == oadd(zp->z_stdoff,
								save)) {
							doabbr(startbuf,
								max_abbr_len + 1,
								zp,
								rp->r_abbrvar,
								rp->r_isdst,
								rp->r_save,
								false);
					}
				}
				eats(zp->z_filename, zp->z_linenum,
					rp->r_filename, rp->r_linenum);
				doabbr(ab, max_abbr_len + 1, zp, rp->r_abbrvar,
				       rp->r_isdst, rp->r_save, false);
				offset = oadd(zp->z_stdoff, rp->r_save);
				if (!want_bloat() && !useuntil && !do_extend
				    && prevrp && lo_time <= prevktime
				    && rp->r_hiyear == ZIC_MAX
				    && prevrp->r_hiyear == ZIC_MAX)
				  break;
				type = addtype(offset, ab, rp->r_isdst,
					rp->r_todisstd, rp->r_todisut);
				if (defaulttype < 0 && !rp->r_isdst)
				  defaulttype = type;
				if (rp->r_hiyear == ZIC_MAX
				    && ! (0 <= lastatmax
					  && ktime < attypes[lastatmax].at))
				  lastatmax = timecnt;
				addtt(ktime, type);
				prevrp = rp;
				prevktime = ktime;
			}
		}
		if (usestart) {
			if (*startbuf == '\0' &&
				zp->z_format != NULL &&
				strchr(zp->z_format, '%') == NULL &&
				strchr(zp->z_format, '/') == NULL)
					strncpy(startbuf, zp->z_format,
					    max_abbr_len + 1 - 1);
			eat(zp->z_filename, zp->z_linenum);
			if (*startbuf == '\0')
error(_("can't determine time zone abbreviation to use just after until time"));
			else {
			  bool isdst = startoff != zp->z_stdoff;
			  type = addtype(startoff, startbuf, isdst,
					 startttisstd, startttisut);
			  if (defaulttype < 0 && !isdst)
			    defaulttype = type;
			  addtt(starttime, type);
			}
		}
		/*
		** Now we may get to set starttime for the next zone line.
		*/
		if (useuntil) {
			startttisstd = zp->z_untilrule.r_todisstd;
			startttisut = zp->z_untilrule.r_todisut;
			starttime = zp->z_untiltime;
			if (!startttisstd)
			  starttime = tadd(starttime, -save);
			if (!startttisut)
			  starttime = tadd(starttime, -stdoff);
		}
	}
	if (defaulttype < 0)
	  defaulttype = 0;
	if (0 <= lastatmax)
	  attypes[lastatmax].dontmerge = true;
	if (do_extend) {
		/*
		** If we're extending the explicitly listed observations
		** for 400 years because we can't fill the POSIX-TZ field,
		** check whether we actually ended up explicitly listing
		** observations through that period.  If there aren't any
		** near the end of the 400-year period, add a redundant
		** one at the end of the final year, to make it clear
		** that we are claiming to have definite knowledge of
		** the lack of transitions up to that point.
		*/
		struct rule xr;
		struct attype *lastat;
		memset(&xr, 0, sizeof(xr));
		xr.r_month = TM_JANUARY;
		xr.r_dycode = DC_DOM;
		xr.r_dayofmonth = 1;
		xr.r_tod = 0;
		for (lastat = attypes, i = 1; i < timecnt; i++)
			if (attypes[i].at > lastat->at)
				lastat = &attypes[i];
		if (!lastat || lastat->at < rpytime(&xr, max_year - 1)) {
			addtt(rpytime(&xr, max_year + 1),
			      lastat ? lastat->type : defaulttype);
			attypes[timecnt - 1].dontmerge = true;
		}
	}
	writezone(zpfirst->z_name, envvar, version, defaulttype);
	free(startbuf);
	free(ab);
	free(envvar);
}

static void
addtt(zic_t starttime, int type)
{
	attypes = growalloc(attypes, sizeof *attypes, timecnt, &timecnt_alloc);
	attypes[timecnt].at = starttime;
	attypes[timecnt].dontmerge = false;
	attypes[timecnt].type = type;
	++timecnt;
}

static int
addtype(zic_t utoff, char const *abbr, bool isdst, bool ttisstd, bool ttisut)
{
	int	i, j;

	if (! (-1L - 2147483647L <= utoff && utoff <= 2147483647L)) {
		error(_("UT offset out of range"));
		exit(EXIT_FAILURE);
	}
	if (!want_bloat())
	  ttisstd = ttisut = false;

	for (j = 0; j < charcnt; ++j)
		if (strcmp(&chars[j], abbr) == 0)
			break;
	if (j == charcnt)
		newabbr(abbr);
	else {
	  /* If there's already an entry, return its index.  */
	  for (i = 0; i < typecnt; i++)
	    if (utoff == utoffs[i] && isdst == isdsts[i] && j == desigidx[i]
		&& ttisstd == ttisstds[i] && ttisut == ttisuts[i])
	      return i;
	}
	/*
	** There isn't one; add a new one, unless there are already too
	** many.
	*/
	if (typecnt >= TZ_MAX_TYPES) {
		error(_("too many local time types"));
		exit(EXIT_FAILURE);
	}
	i = typecnt++;
	utoffs[i] = utoff;
	isdsts[i] = isdst;
	ttisstds[i] = ttisstd;
	ttisuts[i] = ttisut;
	desigidx[i] = j;
	return i;
}

static void
leapadd(zic_t t, int correction, int rolling)
{
	int	i;

	if (TZ_MAX_LEAPS <= leapcnt) {
		error(_("too many leap seconds"));
		exit(EXIT_FAILURE);
	}
	if (rolling && (lo_time != min_time || hi_time != max_time)) {
	  error(_("Rolling leap seconds not supported with -r"));
	  exit(EXIT_FAILURE);
	}
	for (i = 0; i < leapcnt; ++i)
		if (t <= trans[i])
			break;
	memmove(&trans[i + 1], &trans[i], (leapcnt - i) * sizeof *trans);
	memmove(&corr[i + 1], &corr[i], (leapcnt - i) * sizeof *corr);
	memmove(&roll[i + 1], &roll[i], (leapcnt - i) * sizeof *roll);
	trans[i] = t;
	corr[i] = correction;
	roll[i] = rolling;
	++leapcnt;
}

static void
adjleap(void)
{
	int	i;
	zic_t	last = 0;
	zic_t	prevtrans = 0;

	/*
	** propagate leap seconds forward
	*/
	for (i = 0; i < leapcnt; ++i) {
		if (trans[i] - prevtrans < 28 * SECSPERDAY) {
			error(_("Leap seconds too close together"));
			exit(EXIT_FAILURE);
		}
		prevtrans = trans[i];
		trans[i] = tadd(trans[i], last);
		last = corr[i] += last;
	}

	if (0 <= leapexpires) {
	  leapexpires = oadd(leapexpires, last);
	  if (! (leapcnt == 0 || (trans[leapcnt - 1] < leapexpires))) {
	    error(_("last Leap time does not precede Expires time"));
	    exit(EXIT_FAILURE);
	  }
	}
}

/* Is A a space character in the C locale?  */
static bool
is_space(char a)
{
	switch (a) {
	  default:
		return false;
	  case ' ': case '\f': case '\n': case '\r': case '\t': case '\v':
	  	return true;
	}
}

/* Is A an alphabetic character in the C locale?  */
static bool
is_alpha(char a)
{
	switch (a) {
	  default:
		return false;
	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
	  case 'v': case 'w': case 'x': case 'y': case 'z':
		return true;
	}
}

/* If A is an uppercase character in the C locale, return its lowercase
   counterpart.  Otherwise, return A.  */
static char
lowerit(char a)
{
	switch (a) {
	  default: return a;
	  case 'A': return 'a'; case 'B': return 'b'; case 'C': return 'c';
	  case 'D': return 'd'; case 'E': return 'e'; case 'F': return 'f';
	  case 'G': return 'g'; case 'H': return 'h'; case 'I': return 'i';
	  case 'J': return 'j'; case 'K': return 'k'; case 'L': return 'l';
	  case 'M': return 'm'; case 'N': return 'n'; case 'O': return 'o';
	  case 'P': return 'p'; case 'Q': return 'q'; case 'R': return 'r';
	  case 'S': return 's'; case 'T': return 't'; case 'U': return 'u';
	  case 'V': return 'v'; case 'W': return 'w'; case 'X': return 'x';
	  case 'Y': return 'y'; case 'Z': return 'z';
	}
}

/* case-insensitive equality */
static ATTRIBUTE_PURE bool
ciequal(const char *ap, const char *bp)
{
	while (lowerit(*ap) == lowerit(*bp++))
		if (*ap++ == '\0')
			return true;
	return false;
}

static ATTRIBUTE_PURE bool
itsabbr(const char *abbr, const char *word)
{
	if (lowerit(*abbr) != lowerit(*word))
		return false;
	++word;
	while (*++abbr != '\0')
		do {
			if (*word == '\0')
				return false;
		} while (lowerit(*word++) != lowerit(*abbr));
	return true;
}

/* Return true if ABBR is an initial prefix of WORD, ignoring ASCII case.  */

static ATTRIBUTE_PURE bool
ciprefix(char const *abbr, char const *word)
{
  do
    if (!*abbr)
      return true;
  while (lowerit(*abbr++) == lowerit(*word++));

  return false;
}

static const struct lookup *
byword(const char *word, const struct lookup *table)
{
	const struct lookup *	foundlp;
	const struct lookup *	lp;

	if (word == NULL || table == NULL)
		return NULL;

	/* If TABLE is LASTS and the word starts with "last" followed
	   by a non-'-', skip the "last" and look in WDAY_NAMES instead.
	   Warn about any usage of the undocumented prefix "last-".  */
	if (table == lasts && ciprefix("last", word) && word[4]) {
	  if (word[4] == '-')
	    warning(_("\"%s\" is undocumented; use \"last%s\" instead"),
		    word, word + 5);
	  else {
	    word += 4;
	    table = wday_names;
	  }
	}

	/*
	** Look for exact match.
	*/
	for (lp = table; lp->l_word != NULL; ++lp)
		if (ciequal(word, lp->l_word))
			return lp;
	/*
	** Look for inexact match.
	*/
	foundlp = NULL;
	for (lp = table; lp->l_word != NULL; ++lp)
		if (ciprefix(word, lp->l_word)) {
			if (foundlp == NULL)
				foundlp = lp;
			else	return NULL;	/* multiple inexact matches */
		}

	if (foundlp && noise) {
	  /* Warn about any backward-compatibility issue with pre-2017c zic.  */
	  bool pre_2017c_match = false;
	  for (lp = table; lp->l_word; lp++)
	    if (itsabbr(word, lp->l_word)) {
	      if (pre_2017c_match) {
		warning(_("\"%s\" is ambiguous in pre-2017c zic"), word);
		break;
	      }
	      pre_2017c_match = true;
	    }
	}

	return foundlp;
}

static char **
getfields(char *cp)
{
	char *	dp;
	char **	array;
	int	nsubs;

	if (cp == NULL)
		return NULL;
	array = zic_malloc(size_product(strlen(cp) + 1, sizeof *array));
	nsubs = 0;
	for ( ; ; ) {
		while (is_space(*cp))
				++cp;
		if (*cp == '\0' || *cp == '#')
			break;
		array[nsubs++] = dp = cp;
		do {
			if ((*dp = *cp++) != '"')
				++dp;
			else while ((*dp = *cp++) != '"')
				if (*dp != '\0')
					++dp;
				else {
				  error(_("Odd number of quotation marks"));
				  exit(EXIT_FAILURE);
				}
		} while (*cp && *cp != '#' && !is_space(*cp));
		if (is_space(*cp))
			++cp;
		*dp = '\0';
	}
	array[nsubs] = NULL;
	return array;
}

static _Noreturn void
time_overflow(void)
{
	error(_("time overflow"));
	exit(EXIT_FAILURE);
}

static ATTRIBUTE_PURE zic_t
oadd(zic_t t1, zic_t t2)
{
	if (t1 < 0 ? t2 < ZIC_MIN - t1 : ZIC_MAX - t1 < t2)
		time_overflow();
	return t1 + t2;
}

static ATTRIBUTE_PURE zic_t
tadd(zic_t t1, zic_t t2)
{
	if (t1 < 0) {
		if (t2 < min_time - t1) {
			if (t1 != min_time)
				time_overflow();
			return min_time;
		}
	} else {
		if (max_time - t1 < t2) {
			if (t1 != max_time)
				time_overflow();
			return max_time;
		}
	}
	return t1 + t2;
}

/*
** Given a rule, and a year, compute the date (in seconds since January 1,
** 1970, 00:00 LOCAL time) in that year that the rule refers to.
*/

static zic_t
rpytime(const struct rule *rp, zic_t wantedy)
{
	int	m, i;
	zic_t	dayoff;			/* with a nod to Margaret O. */
	zic_t	t, y;
	int yrem;

	if (wantedy == ZIC_MIN)
		return min_time;
	if (wantedy == ZIC_MAX)
		return max_time;
	m = TM_JANUARY;
	y = EPOCH_YEAR;

	/* dayoff = floor((wantedy - y) / YEARSPERREPEAT) * DAYSPERREPEAT,
	   sans overflow.  */
	yrem = wantedy % YEARSPERREPEAT - y % YEARSPERREPEAT;
	dayoff = ((wantedy / YEARSPERREPEAT - y / YEARSPERREPEAT
		   + yrem / YEARSPERREPEAT - (yrem % YEARSPERREPEAT < 0))
		  * DAYSPERREPEAT);
	/* wantedy = y + ((wantedy - y) mod YEARSPERREPEAT), sans overflow.  */
	wantedy = y + (yrem + 2 * YEARSPERREPEAT) % YEARSPERREPEAT;

	while (wantedy != y) {
		i = len_years[isleap(y)];
		dayoff = oadd(dayoff, i);
		y++;
	}
	while (m != rp->r_month) {
		i = len_months[isleap(y)][m];
		dayoff = oadd(dayoff, i);
		++m;
	}
	i = rp->r_dayofmonth;
	if (m == TM_FEBRUARY && i == 29 && !isleap(y)) {
		if (rp->r_dycode == DC_DOWLEQ)
			--i;
		else {
			error(_("use of 2/29 in non leap-year"));
			exit(EXIT_FAILURE);
		}
	}
	--i;
	dayoff = oadd(dayoff, i);
	if (rp->r_dycode == DC_DOWGEQ || rp->r_dycode == DC_DOWLEQ) {
		/*
		** Don't trust mod of negative numbers.
		*/
		zic_t wday = ((EPOCH_WDAY + dayoff % DAYSPERWEEK + DAYSPERWEEK)
			      % DAYSPERWEEK);
		while (wday != rp->r_wday)
			if (rp->r_dycode == DC_DOWGEQ) {
				dayoff = oadd(dayoff, (zic_t) 1);
				if (++wday >= DAYSPERWEEK)
					wday = 0;
				++i;
			} else {
				dayoff = oadd(dayoff, (zic_t) -1);
				if (--wday < 0)
					wday = DAYSPERWEEK - 1;
				--i;
			}
		if (i < 0 || i >= len_months[isleap(y)][m]) {
			if (noise)
				warning(_("rule goes past start/end of month; \
will not work with pre-2004 versions of zic"));
		}
	}
	if (dayoff < min_time / SECSPERDAY)
		return min_time;
	if (dayoff > max_time / SECSPERDAY)
		return max_time;
	t = (zic_t) dayoff * SECSPERDAY;
	return tadd(t, rp->r_tod);
}

static void
newabbr(const char *string)
{
	int	i;

	if (strcmp(string, GRANDPARENTED) != 0) {
		const char *	cp;
		const char *	mp;

		cp = string;
		mp = NULL;
		while (is_alpha(*cp) || ('0' <= *cp && *cp <= '9')
		       || *cp == '-' || *cp == '+')
				++cp;
		if (noise && cp - string < 3)
		  mp = _("time zone abbreviation has fewer than 3 characters");
		if (cp - string > ZIC_MAX_ABBR_LEN_WO_WARN)
		  mp = _("time zone abbreviation has too many characters");
		if (*cp != '\0')
mp = _("time zone abbreviation differs from POSIX standard");
		if (mp != NULL)
			warning("%s (%s)", mp, string);
	}
	i = strlen(string) + 1;
	if (charcnt + i > TZ_MAX_CHARS) {
		error(_("too many, or too long, time zone abbreviations"));
		exit(EXIT_FAILURE);
	}
	strncpy(&chars[charcnt], string, sizeof(chars) - charcnt - 1);
	charcnt += i;
}

/* Ensure that the directories of ARGNAME exist, by making any missing
   ones.  If ANCESTORS, do this only for ARGNAME's ancestors; otherwise,
   do it for ARGNAME too.  Exit with failure if there is trouble.
   Do not consider an existing file to be trouble.  */
static void
mkdirs(char const *argname, bool ancestors)
{
	char *	name;
	char *	cp;

	cp = name = ecpyalloc(argname);

	/* On MS-Windows systems, do not worry about drive letters or
	   backslashes, as this should suffice in practice.  Time zone
	   names do not use drive letters and backslashes.  If the -d
	   option of zic does not name an already-existing directory,
	   it can use slashes to separate the already-existing
	   ancestor prefix from the to-be-created subdirectories.  */

	/* Do not mkdir a root directory, as it must exist.  */
	while (*cp == '/')
	  cp++;

	while (cp && ((cp = strchr(cp, '/')) || !ancestors)) {
		if (cp)
		  *cp = '\0';
		/*
		** Try to create it.  It's OK if creation fails because
		** the directory already exists, perhaps because some
		** other process just created it.  For simplicity do
		** not check first whether it already exists, as that
		** is checked anyway if the mkdir fails.
		*/
		if (mkdir(name, MKDIR_UMASK) != 0) {
			/* Do not report an error if err == EEXIST, because
			   some other process might have made the directory
			   in the meantime.  Likewise for ENOSYS, because
			   Solaris 10 mkdir fails with ENOSYS if the
			   directory is an automounted mount point.  */
			int err = errno;
			if (err != EEXIST && err != ENOSYS) {
				error(_("%s: Can't create directory %s: %s"),
				      progname, name, strerror(err));
				exit(EXIT_FAILURE);
			}
		}
		if (cp)
		  *cp++ = '/';
	}
	free(name);
}