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

/*	$NetBSD: zic.c,v 1.46.2.1.4.1 2017/01/18 08:46:23 skrll Exp $	*/
/*
** This file is in the public domain, so clarified as of
** 2006-07-17 by Arthur David Olson.
*/

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

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: zic.c,v 1.46.2.1.4.1 2017/01/18 08:46:23 skrll Exp $");
#endif /* !defined lint */

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

#include <stdarg.h>
#include <unistd.h>

#define	ZIC_VERSION_PRE_2013 '2'
#define	ZIC_VERSION	'3'

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 */

#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

#define end(cp)	(strchr((cp), '\0'))

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

	zic_t		r_loyear;	/* for example, 1986 */
	zic_t		r_hiyear;	/* for example, 1986 */
	const char *	r_yrtype;
	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;	/* above is standard time if 1 */
					/* or wall clock time if 0 */
	bool		r_todisgmt;	/* above is GMT if 1 */
					/* or local time if 0 */
	zic_t		r_stdoff;	/* offset from standard time */
	const char *	r_abbrvar;	/* variable part of abbreviation */

	int		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;
	int		z_linenum;

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

	zic_t		z_stdoff;

	struct rule *	z_rules;
	int		z_nrules;

	struct rule	z_untilrule;
	zic_t		z_untiltime;
};

extern int	getopt(int argc, char * const argv[],
			const char * options);
extern int	link(const char * fromname, const char * toname);
extern char *	optarg;
extern int	optind;

#if ! HAVE_LINK
# define link(from, to) (-1)
#endif
#if ! HAVE_SYMLINK
# define symlink(from, to) (-1)
#endif

static void	addtt(zic_t starttime, int type);
static int	addtype(zic_t, char * const, bool, bool, bool);
static void	leapadd(zic_t, bool, int, int);
static void	adjleap(void);
static void	associate(void);
static void	dolink(const char * fromfield, const char * tofield);
static char **	getfields(char * buf);
static zic_t	gethms(const char * string, const char * errstring,
			bool);
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 ** fields, int nfields, int iscont);
static int	itsdir(const char * name);
static bool	is_alpha(char a);
static char	lowerit(char);
static bool	mkdirs(char * filename);
static void	newabbr(const char * abbr);
static zic_t	oadd(zic_t t1, zic_t t2);
static void	outzone(const struct zone * zp, int ntzones);
static int	rcomp(const void * leftp, const void * rightp);
static zic_t	rpytime(const struct rule * rp, zic_t wantedy);
static void	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);
static bool	yearistype(int year, const char * type);
static int	atcomp(const void *avp, const void *bvp);
static void	updateminmax(zic_t x);

/* 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
   tz binary 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.  */
enum { WORK_AROUND_QTBUG_53071 = 1 };

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 int		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 int		rlinenum;
static const char *	progname;
static int		timecnt;
static int		timecnt_alloc;
static int		typecnt;

/*
** Line codes.
*/

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

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

#define ZF_NAME		1
#define ZF_GMTOFF	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_GMTOFF	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_STDOFF	8
#define RF_ABBRVAR	9
#define RULE_FIELDS	10

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

#define LF_FROM		1
#define LF_TO		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

/*
** Year synonyms.
*/

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

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

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

struct link {
	const char *	l_filename;
	int		l_linenum;
	const char *	l_from;
	const char *	l_to;
};

static struct link *	links;
static int		nlinks;
static int		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	line_codes[] = {
	{ "Rule",	LC_RULE },
	{ "Zone",	LC_ZONE },
	{ "Link",	LC_LINK },
	{ "Leap",	LC_LEAP },
	{ 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		gmtoffs[TZ_MAX_TYPES];
static char		isdsts[TZ_MAX_TYPES];
static unsigned char	abbrinds[TZ_MAX_TYPES];
static bool		ttisstds[TZ_MAX_TYPES];
static bool		ttisgmts[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 void *
memcheck(void *const ptr)
{
	if (ptr == NULL)
		memory_exhausted(strerror(errno));
	return ptr;
}

#define emalloc(size)		memcheck(malloc(size))
#define erealloc(ptr, size)	memcheck(realloc((ptr), (size)))
#define ecpyalloc(ptr)		memcheck(icpyalloc(ptr))
#define ecatalloc(oldp, newp)	memcheck(icatalloc((oldp), (newp)))

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

/*
** Error handling.
*/

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

static void
eat(const char *const name, const int 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.
	*/
	fprintf(stderr, _("\"%s\", line %d: "), filename, linenum);
	vfprintf(stderr, string, args);
	if (rfilename != NULL)
		fprintf(stderr, _(" (rule from \"%s\", line %d)"),
			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;
}

static void
close_file(FILE *stream, char const *name)
{
  char const *e = (ferror(stream) ? _("I/O error")
		   : fclose(stream) != 0 ? strerror(errno) : NULL);
  if (e) {
    fprintf(stderr, "%s: ", progname);
    if (name)
      fprintf(stderr, "%s: ", name);
    fprintf(stderr, "%s\n", e);
    exit(EXIT_FAILURE);
  }
}

static _Noreturn void
usage(FILE *stream, int status)
{
  fprintf(stream,
	  _("%s: usage is %s [ --version ] [ --help ] [ -v ] \\\n"
	    "\t[ -l localtime ] [ -p posixrules ] [ -d directory ] \\\n"
	    "\t[ -L leapseconds ] [ -y yearistype ] [ filename ... ]\n\n"
	    "Report bugs to %s.\n"),
	  progname, progname, REPORT_BUGS_TO);
  if (status == EXIT_SUCCESS)
    close_file(stream, NULL);
  exit(status);
}

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

int
main(int argc, char *argv[])
{
	int	i;
	int	j;
	int	c;

#ifdef S_IWGRP
	(void) umask(umask(S_IWGRP | S_IWOTH) | (S_IWGRP | S_IWOTH));
#endif
#if HAVE_GETTEXT - 0
	(void) setlocale(LC_MESSAGES, "");
#ifdef TZ_DOMAINDIR
	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
#endif /* defined TEXTDOMAINDIR */
	(void) textdomain(TZ_DOMAIN);
#endif /* HAVE_GETTEXT */
	progname = argv[0];
	if (TYPE_BIT(zic_t) < 64) {
		(void) fprintf(stderr, "%s: %s\n", progname,
			_("wild compilation-time specification of zic_t"));
		return EXIT_FAILURE;
	}
	for (i = 1; i < argc; ++i)
		if (strcmp(argv[i], "--version") == 0) {
			(void) printf("zic %s%s\n", PKGVERSION, TZVERSION);
			close_file(stdout, NULL);
			return EXIT_SUCCESS;
		} else if (strcmp(argv[i], "--help") == 0) {
			usage(stdout, EXIT_SUCCESS);
		}
	while ((c = getopt(argc, argv, "d:l:p:L:vsy:")) != EOF && c != -1)
		switch (c) {
			default:
				usage(stderr, EXIT_FAILURE);
			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 'y':
				if (yitcommand == NULL)
					yitcommand = optarg;
				else {
					fprintf(stderr,
_("%s: More than one -y option specified\n"),
						progname);
					return EXIT_FAILURE;
				}
				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 's':
				warning(_("-s ignored"));
				break;
		}
	if (optind == argc - 1 && strcmp(argv[optind], "=") == 0)
		usage(stderr, EXIT_FAILURE);	/* usage message by request */
	if (directory == NULL)
		directory = TZDIR;
	if (yitcommand == NULL)
		yitcommand = "yearistype";

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

	for (i = optind; i < argc; ++i)
		infile(argv[i]);
	if (errors)
		return EXIT_FAILURE;
	associate();
	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_from, links[i].l_to);
		if (noise)
			for (j = 0; j < nlinks; ++j)
				if (strcmp(links[i].l_to,
					links[j].l_from) == 0)
						warning(_("link to link"));
	}
	if (lcltime != NULL) {
		eat(_("command line"), 1);
		dolink(lcltime, TZDEFAULT);
	}
	if (psxrules != NULL) {
		eat(_("command line"), 1);
		dolink(psxrules, TZDEFRULES);
	}
	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);
}

static void
dolink(const char *const fromfield, const char *const tofield)
{
	char *	fromname;
	char *	toname;
	int fromisdir;

	namecheck(tofield);
	if (fromfield[0] == '/')
		fromname = ecpyalloc(fromfield);
	else {
		fromname = ecpyalloc(directory);
		fromname = ecatalloc(fromname, "/");
		fromname = ecatalloc(fromname, fromfield);
	}
	if (tofield[0] == '/')
		toname = ecpyalloc(tofield);
	else {
		toname = ecpyalloc(directory);
		toname = ecatalloc(toname, "/");
		toname = ecatalloc(toname, tofield);
	}
	/*
	** We get to be careful here since
	** there's a fair chance of root running us.
	*/
	fromisdir = itsdir(fromname);
	if (fromisdir) {
		char const *e = strerror(fromisdir < 0 ? errno : EPERM);
		fprintf(stderr, _("%s: link from %s failed: %s"),
			progname, fromname, e);
		exit(EXIT_FAILURE);
	}
	if (itsdir(toname) <= 0)
		remove(toname);
	if (link(fromname, toname) != 0) {
		int	result;

		if (! mkdirs(toname))
			exit(EXIT_FAILURE);

		result = link(fromname, toname);
		if (result != 0) {
				const char *s = fromfield;
				const char *t;
				char * symlinkcontents = NULL;

				do
					 t = s;
				while ((s = strchr(s, '/'))
				       && ! strncmp (fromfield, tofield,
						     ++s - fromfield));

				for (s = tofield + (t - fromfield);
				     (s = strchr(s, '/'));
				     s++)
					symlinkcontents =
						ecatalloc(symlinkcontents,
						"../");
				symlinkcontents = ecatalloc(symlinkcontents, t);
				result = symlink(symlinkcontents, toname);
				if (result == 0)
warning(_("hard link failed, symbolic link used"));
				free(symlinkcontents);
		}
		if (result != 0) {
			FILE *fp, *tp;
			int c;
			fp = fopen(fromname, "rb");
			if (!fp) {
				const char *e = strerror(errno);
				fprintf(stderr,
					       _("%s: Can't read %s: %s\n"),
					       progname, fromname, e);
				exit(EXIT_FAILURE);
			}
			tp = fopen(toname, "wb");
			if (!tp) {
				const char *e = strerror(errno);
				fprintf(stderr,
					       _("%s: Can't create %s: %s\n"),
					       progname, toname, e);
				exit(EXIT_FAILURE);
			}
			while ((c = getc(fp)) != EOF)
				putc(c, tp);
			close_file(fp, fromname);
			close_file(tp, toname);
			warning(_("link failed, copy used"));
		}
	}
	free(fromname);
	free(toname);
}

#define TIME_T_BITS_IN_FILE	64

static const zic_t min_time = (zic_t) -1 << (TIME_T_BITS_IN_FILE - 1);
static const zic_t max_time = -1 - ((zic_t) -1 << (TIME_T_BITS_IN_FILE - 1));

/* Estimated time of the Big Bang, in seconds since the POSIX epoch.
   rounded downward to the negation of a power of two that is
   comfortably outside the error bounds.

   zic does not output time stamps before this, partly because they
   are physically suspect, and partly because GNOME mishandles them; see
   GNOME bug 730332 <https://bugzilla.gnome.org/show_bug.cgi?id=730332>.

   For the time of the Big Bang, see:

   Ade PAR, Aghanim N, Armitage-Caplan C et al.  Planck 2013 results.
   I. Overview of products and scientific results.
   arXiv:1303.5062 2013-03-20 20:10:01 UTC
   <http://arxiv.org/pdf/1303.5062v1> [PDF]

   Page 36, Table 9, row Age/Gyr, column Planck+WP+highL+BAO 68% limits
   gives the value 13.798 plus-or-minus 0.037 billion years.
   Multiplying this by 1000000000 and then by 31557600 (the number of
   seconds in an astronomical year) gives a value that is comfortably
   less than 2**59, so BIG_BANG is - 2**59.

   BIG_BANG is approximate, and may change in future versions.
   Please do not rely on its exact value.  */

#ifndef BIG_BANG
#define BIG_BANG (- (1LL << 59))
#endif

/* If true, work around GNOME bug 730332
   <https://bugzilla.gnome.org/show_bug.cgi?id=730332>
   by refusing to output time stamps before BIG_BANG.
   Such time stamps are physically suspect anyway.

   The GNOME bug is scheduled to be fixed in GNOME 3.22, and if so
   this workaround will no longer be needed when GNOME 3.21 and
   earlier are obsolete, say in the year 2021.  */
enum { WORK_AROUND_GNOME_BUG_730332 = true };

static const zic_t early_time = (WORK_AROUND_GNOME_BUG_730332
				 ? BIG_BANG
				 : MINVAL(zic_t, TIME_T_BITS_IN_FILE));

/* Return 1 if NAME is a directory, 0 if it's something else, -1 if trouble.  */
static int
itsdir(const char *const name)
{
	struct stat st;
	int res = stat(name, &st);
	if (res != 0)
		return res;
#ifdef S_ISDIR
	return S_ISDIR(st.st_mode) != 0;
#else
	{
		char *nameslashdot = ecatalloc(ecpyalloc(name), "/.");
		res = stat(nameslashdot, &st);
		free(nameslashdot);
		return res == 0;
	}
#endif
}

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

/*
** Sort by rule name.
*/

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

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

	if (nrules != 0) {
		(void) 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_stdoff = gethms(zp->z_rule, _("unruly zone"),
				true);
			/*
			** 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;
	int			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 {
			lp = byword(fields[0], line_codes);
			if (lp == NULL)
				error(_("input line of unknown type"));
			else switch ((int) (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:
					if (name != leapsec)
						warning(
_("%s: Leap line in non leap seconds file %s"),
							progname, name);
					else	inleap(fields, nfields);
					wantcont = false;
					break;
				default:	/* "cannot happen" */
					fprintf(stderr,
_("%s: panic: Invalid l_value %d\n"),
						progname, lp->l_value);
					exit(EXIT_FAILURE);
			}
		}
		free(fields);
	}
	close_file(fp, filename);
	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, bool signable)
{
	zic_t	hh;
	int	mm, ss, sign;

	if (string == NULL || *string == '\0')
		return 0;
	if (!signable)
		sign = 1;
	else if (*string == '-') {
		sign = -1;
		++string;
	} else	sign = 1;
	if (sscanf(string, scheck(string, "%"SCNdZIC), &hh) == 1)
		mm = ss = 0;
	else if (sscanf(string, scheck(string, "%"SCNdZIC":%d"), &hh, &mm) == 2)
		ss = 0;
	else if (sscanf(string, scheck(string, "%"SCNdZIC":%d:%d"),
		&hh, &mm, &ss) != 3) {
			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;
	}
	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 void
inrule(char **const fields, const int nfields)
{
	static struct rule	r;

	if (nfields != RULE_FIELDS) {
		error(_("wrong number of fields on Rule line"));
		return;
	}
	if (*fields[RF_NAME] == '\0') {
		error(_("nameless rule"));
		return;
	}
	r.r_filename = filename;
	r.r_linenum = linenum;
	r.r_stdoff = gethms(fields[RF_STDOFF], _("invalid saved time"), true);
	rulesub(&r, fields[RF_LOYEAR], fields[RF_HIYEAR], fields[RF_COMMAND],
		fields[RF_MONTH], fields[RF_DAY], fields[RF_TOD]);
	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 **const fields, const int nfields)
{
	int	i;

	if (nfields < ZONE_MINFIELDS || nfields > ZONE_MAXFIELDS) {
		error(_("wrong number of fields on Zone line"));
		return false;
	}
	if (strcmp(fields[ZF_NAME], TZDEFAULT) == 0 && lcltime != NULL) {
		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 %d)"),
					fields[ZF_NAME],
					zones[i].z_filename,
					zones[i].z_linenum);
				return false;
		}
	return inzsub(fields, nfields, false);
}

static bool
inzcont(char **const fields, const 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 **const fields, const int nfields, const int iscont)
{
	char *		cp;
	char *		cp1;
	static struct zone	z;
	int		i_gmtoff, i_rule, i_format;
	int		i_untilyear, i_untilmonth;
	int		i_untilday, i_untiltime;
	bool		hasuntil;

	if (iscont) {
		i_gmtoff = ZFC_GMTOFF;
		i_rule = ZFC_RULE;
		i_format = ZFC_FORMAT;
		i_untilyear = ZFC_TILYEAR;
		i_untilmonth = ZFC_TILMONTH;
		i_untilday = ZFC_TILDAY;
		i_untiltime = ZFC_TILTIME;
		z.z_name = NULL;
	} else if (!namecheck(fields[ZF_NAME]))
		return false;
	else {
		i_gmtoff = ZF_GMTOFF;
		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_name = ecpyalloc(fields[ZF_NAME]);
	}
	z.z_filename = filename;
	z.z_linenum = linenum;
	z.z_gmtoff = gethms(fields[i_gmtoff], _("invalid UT offset"), true);
	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_rule = ecpyalloc(fields[i_rule]);
	z.z_format = cp1 = ecpyalloc(fields[i_format]);
	z.z_format_specifier = cp ? *cp : '\0';
	if (z.z_format_specifier == 'z') {
	  if (noise)
	    warning(_("format '%s' not handled by pre-2015 versions of zic"),
		    z.z_format);
	  cp1[cp - fields[i_format]] = 's';
	}
	if (max_format_len < strlen(z.z_format))
		max_format_len = strlen(z.z_format);
	hasuntil = nfields > i_untilyear;
	if (hasuntil) {
		z.z_untilrule.r_filename = filename;
		z.z_untilrule.r_linenum = linenum;
		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");
		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;
		}
	}
	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 void
inleap(char **const fields, const int nfields)
{
	const char *		cp;
	const struct lookup *	lp;
	int			i, j;
	zic_t			year;
	int			month, day;
	zic_t			dayoff, tod;
	zic_t			t;

	if (nfields != LEAP_FIELDS) {
		error(_("wrong number of fields on Leap line"));
		return;
	}
	dayoff = 0;
	cp = fields[LP_YEAR];
	if (sscanf(cp, scheck(cp, "%"SCNdZIC), &year) != 1) {
		/*
		** Leapin' Lizards!
		*/
		error(_("invalid leaping year"));
		return;
	}
	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;
	}
	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, scheck(cp, "%d"), &day) != 1 ||
		day <= 0 || day > len_months[isleap(year)][month]) {
			error(_("invalid day of month"));
			return;
	}
	dayoff = oadd(dayoff, day - 1);
	if (dayoff < min_time / SECSPERDAY) {
		error(_("time too small"));
		return;
	}
	if (dayoff > max_time / SECSPERDAY) {
		error(_("time too large"));
		return;
	}
	t = dayoff * SECSPERDAY;
	tod = gethms(fields[LP_TIME], _("invalid time of day"), false);
	cp = fields[LP_CORR];
	{
		bool	positive;
		int	count;

		if (strcmp(cp, "") == 0) { /* infile() turns "-" into "" */
			positive = false;
			count = 1;
		} else if (strcmp(cp, "--") == 0) {
			positive = false;
			count = 2;
		} else if (strcmp(cp, "+") == 0) {
			positive = true;
			count = 1;
		} else if (strcmp(cp, "++") == 0) {
			positive = true;
			count = 2;
		} else {
			error(_("illegal CORRECTION field on Leap line"));
			return;
		}
		if ((lp = byword(fields[LP_ROLL], leap_types)) == NULL) {
			error(_(
				"illegal Rolling/Stationary field on Leap line"
				));
			return;
		}
		t = tadd(t, tod);
		if (t < early_time) {
			error(_("leap second precedes Big Bang"));
			return;
		}
		leapadd(t, positive, lp->l_value, count);
	}
}

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

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

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

	if ((lp = byword(monthp, mon_names)) == NULL) {
		error(_("invalid month name"));
		return;
	}
	rp->r_month = lp->l_value;
	rp->r_todisstd = false;
	rp->r_todisgmt = false;
	dp = ecpyalloc(timep);
	if (*dp != '\0') {
		ep = dp + strlen(dp) - 1;
		switch (lowerit(*ep)) {
			case 's':	/* Standard */
				rp->r_todisstd = true;
				rp->r_todisgmt = false;
				*ep = '\0';
				break;
			case 'w':	/* Wall */
				rp->r_todisstd = false;
				rp->r_todisgmt = false;
				*ep = '\0';
				break;
			case 'g':	/* Greenwich */
			case 'u':	/* Universal */
			case 'z':	/* Zulu */
				rp->r_todisstd = true;
				rp->r_todisgmt = true;
				*ep = '\0';
				break;
		}
	}
	rp->r_tod = gethms(dp, _("invalid time of day"), false);
	free(dp);
	/*
	** Year work.
	*/
	cp = loyearp;
	lp = byword(cp, begin_years);
	rp->r_lowasnum = lp == NULL;
	if (!rp->r_lowasnum) switch ((int) lp->l_value) {
		case YR_MINIMUM:
			rp->r_loyear = ZIC_MIN;
			break;
		case YR_MAXIMUM:
			rp->r_loyear = ZIC_MAX;
			break;
		default:	/* "cannot happen" */
			fprintf(stderr,
				_("%s: panic: Invalid l_value %d\n"),
				progname, lp->l_value);
			exit(EXIT_FAILURE);
	} else if (sscanf(cp, scheck(cp, "%"SCNdZIC), &rp->r_loyear) != 1) {
		error(_("invalid starting year"));
		return;
	}
	cp = hiyearp;
	lp = byword(cp, end_years);
	rp->r_hiwasnum = lp == NULL;
	if (!rp->r_hiwasnum) switch ((int) 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:	/* "cannot happen" */
			fprintf(stderr,
				_("%s: panic: Invalid l_value %d\n"),
				progname, lp->l_value);
			exit(EXIT_FAILURE);
	} else if (sscanf(cp, scheck(cp, "%"SCNdZIC), &rp->r_hiyear) != 1) {
		error(_("invalid ending year"));
		return;
	}
	if (rp->r_loyear > rp->r_hiyear) {
		error(_("starting year greater than ending year"));
		return;
	}
	if (*typep == '\0')
		rp->r_yrtype = NULL;
	else {
		if (rp->r_loyear == rp->r_hiyear) {
			error(_("typed single year"));
			return;
		}
		rp->r_yrtype = ecpyalloc(typep);
	}
	/*
	** Day work.
	** Accept things such as:
	**	1
	**	last-Sunday
	**	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;
			}
			if ((lp = byword(dp, wday_names)) == NULL) {
				error(_("invalid weekday name"));
				free(dp);
				return;
			}
			rp->r_wday = lp->l_value;
		}
		if (sscanf(ep, scheck(ep, "%d"), &rp->r_dayofmonth) != 1 ||
			rp->r_dayofmonth <= 0 ||
			(rp->r_dayofmonth > len_months[1][rp->r_month])) {
				error(_("invalid day of month"));
				free(dp);
				return;
		}
	}
	free(dp);
}

static void
convert(const zic_t val, char *const 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;
}

static void
convert64(const zic_t val, char *const 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;
}

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

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

static void
puttzcode64(const zic_t val, FILE *const fp)
{
	char	buf[8];

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

static int
atcomp(const void *avp, const void *bvp)
{
	const zic_t	a = ((const struct attype *) avp)->at;
	const zic_t	b = ((const struct attype *) bvp)->at;

	return (a < b) ? -1 : (a > b);
}

static bool
is32(const zic_t x)
{
	return INT32_MIN <= x && x <= INT32_MAX;
}

static void
writezone(const char *const name, const char *const string, char version)
{
	FILE *			fp;
	int			i, j;
	int			leapcnt32, leapi32;
	int			timecnt32, timei32;
	int			pass;
	static char *			fullname;
	static const struct tzhead	tzh0;
	static struct tzhead		tzh;
	zic_t one = 1;
	zic_t y2038_boundary = one << 31;
	ptrdiff_t nats = timecnt + WORK_AROUND_QTBUG_53071;
	zic_t *ats = emalloc(size_product(nats, sizeof *ats + 1));
	void *typesptr = ats + nats;
	unsigned char *types = typesptr;

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

		toi = 0;
		fromi = 0;
		while (fromi < timecnt && attypes[fromi].at < early_time)
			++fromi;
		for ( ; fromi < timecnt; ++fromi) {
			if (toi > 1 && ((attypes[fromi].at +
				gmtoffs[attypes[toi - 1].type]) <=
				(attypes[toi - 1].at +
				gmtoffs[attypes[toi - 2].type]))) {
					attypes[toi - 1].type =
						attypes[fromi].type;
					continue;
			}
			if (toi == 0
			    || attypes[fromi].dontmerge
			    || attypes[toi - 1].type != attypes[fromi].type)
					attypes[toi++] = attypes[fromi];
		}
		timecnt = toi;
	}
	if (noise && timecnt > 1200)
		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;
	}

	/* Work around QTBUG-53071 for time stamps 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.  */
	if (WORK_AROUND_QTBUG_53071 && timecnt != 0
	    && ats[timecnt - 1] < y2038_boundary - 1 && strchr(string, '<')) {
	  ats[timecnt] = y2038_boundary - 1;
	  types[timecnt] = types[timecnt - 1];
	  timecnt++;
	}

	/*
	** 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;
			}
	}
	/*
	** Figure out 32-bit-limited starts and counts.
	*/
	timecnt32 = timecnt;
	timei32 = 0;
	leapcnt32 = leapcnt;
	leapi32 = 0;
	while (timecnt32 > 0 && !is32(ats[timecnt32 - 1]))
		--timecnt32;
	while (timecnt32 > 0 && !is32(ats[timei32])) {
		--timecnt32;
		++timei32;
	}
	/*
	** Output an INT32_MIN "transition" if appropriate; see below.
	*/
	if (timei32 > 0 && ats[timei32] > INT32_MIN) {
		--timei32;
		++timecnt32;
	}
	while (leapcnt32 > 0 && !is32(trans[leapcnt32 - 1]))
		--leapcnt32;
	while (leapcnt32 > 0 && !is32(trans[leapi32])) {
		--leapcnt32;
		++leapi32;
	}
	fullname = erealloc(fullname,
	    strlen(directory) + 1 + strlen(name) + 1);
	(void) sprintf(fullname, "%s/%s", directory, name);	/* XXX: sprintf is safe */
	/*
	** Remove old file, if any, to snap links.
	*/
	if (itsdir(fullname) <= 0 && remove(fullname) != 0 && errno != ENOENT) {
		const char *e = strerror(errno);

		(void) fprintf(stderr, _("%s: Can't remove %s: %s\n"),
			progname, fullname, e);
		exit(EXIT_FAILURE);
	}
	if ((fp = fopen(fullname, "wb")) == NULL) {
		if (! mkdirs(fullname))
			exit(EXIT_FAILURE);
		if ((fp = fopen(fullname, "wb")) == NULL) {
			const char *e = strerror(errno);

			(void) fprintf(stderr, _("%s: Can't create %s: %s\n"),
				progname, fullname, e);
			exit(EXIT_FAILURE);
		}
	}
	for (pass = 1; pass <= 2; ++pass) {
		int	thistimei, thistimecnt;
		int	thisleapi, thisleapcnt;
		int	thistimelim, thisleaplim;
		int		writetype[TZ_MAX_TYPES];
		int		typemap[TZ_MAX_TYPES];
		int	thistypecnt;
		char		thischars[TZ_MAX_CHARS];
		char		thischarcnt;
		bool		toomanytimes;
		int		indmap[TZ_MAX_CHARS];

		if (pass == 1) {
			thistimei = timei32;
			thistimecnt = timecnt32;
			toomanytimes = thistimecnt >> 31 >> 1 != 0;
			thisleapi = leapi32;
			thisleapcnt = leapcnt32;
		} else {
			thistimei = 0;
			thistimecnt = timecnt;
			toomanytimes = thistimecnt >> 31 >> 31 >> 2 != 0;
			thisleapi = 0;
			thisleapcnt = leapcnt;
		}
		if (toomanytimes)
		  error(_("too many transition times"));
		thistimelim = thistimei + thistimecnt;
		thisleaplim = thisleapi + thisleapcnt;
		for (i = 0; i < typecnt; ++i)
			writetype[i] = thistimecnt == timecnt;
		if (thistimecnt == 0) {
			/*
			** No transition times fall in the current
			** (32- or 64-bit) window.
			*/
			if (typecnt != 0)
				writetype[typecnt - 1] = true;
		} else {
			for (i = thistimei - 1; i < thistimelim; ++i)
				if (i >= 0)
					writetype[types[i]] = true;
			/*
			** For America/Godthab and Antarctica/Palmer
			*/
			if (thistimei == 0)
				writetype[0] = true;
		}
#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).
		*/
		{
			int	mrudst, mrustd, hidst, histd, type;

			hidst = histd = mrudst = mrustd = -1;
			for (i = thistimei; i < thistimelim; ++i) {
				if (i < 0)
					continue;
				if (isdsts[types[i]])
					mrudst = types[i];
				else	mrustd = types[i];
			}
			for (i = 0; i < typecnt; ++i)
				if (writetype[i]) {
					if (isdsts[i])
						hidst = i;
					else	histd = i;
				}
			if (hidst >= 0 && mrudst >= 0 && hidst != mrudst &&
				gmtoffs[hidst] != gmtoffs[mrudst]) {
					isdsts[mrudst] = -1;
					type = addtype(gmtoffs[mrudst],
						&chars[abbrinds[mrudst]],
						true,
						ttisstds[mrudst],
						ttisgmts[mrudst]);
					isdsts[mrudst] = 1;
					writetype[type] = true;
			}
			if (histd >= 0 && mrustd >= 0 && histd != mrustd &&
				gmtoffs[histd] != gmtoffs[mrustd]) {
					isdsts[mrustd] = -1;
					type = addtype(gmtoffs[mrustd],
						&chars[abbrinds[mrustd]],
						false,
						ttisstds[mrustd],
						ttisgmts[mrustd]);
					isdsts[mrustd] = 0;
					writetype[type] = true;
			}
		}
#endif /* !defined LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH */
		thistypecnt = 0;
		for (i = 0; i < typecnt; ++i)
			typemap[i] = writetype[i] ?  thistypecnt++ : -1;
		for (i = 0; i < (int)(sizeof indmap / sizeof indmap[0]); ++i)
			indmap[i] = -1;
		thischarcnt = 0;
		for (i = 0; i < typecnt; ++i) {
			char *	thisabbr;

			if (!writetype[i])
				continue;
			if (indmap[abbrinds[i]] >= 0)
				continue;
			thisabbr = &chars[abbrinds[i]];
			for (j = 0; j < thischarcnt; ++j)
				if (strcmp(&thischars[j], thisabbr) == 0)
					break;
			if (j == thischarcnt) {
				(void) strcpy(&thischars[(int) thischarcnt],
					thisabbr);
				thischarcnt += strlen(thisabbr) + 1;
			}
			indmap[abbrinds[i]] = j;
		}
#define DO(field)	(void) fwrite(tzh.field, \
				sizeof tzh.field, (size_t) 1, fp)
		tzh = tzh0;
		(void) strncpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
		tzh.tzh_version[0] = version;
		convert(thistypecnt, tzh.tzh_ttisgmtcnt);
		convert(thistypecnt, tzh.tzh_ttisstdcnt);
		convert(thisleapcnt, tzh.tzh_leapcnt);
		convert(thistimecnt, tzh.tzh_timecnt);
		convert(thistypecnt, tzh.tzh_typecnt);
		convert(thischarcnt, tzh.tzh_charcnt);
		DO(tzh_magic);
		DO(tzh_version);
		DO(tzh_reserved);
		DO(tzh_ttisgmtcnt);
		DO(tzh_ttisstdcnt);
		DO(tzh_leapcnt);
		DO(tzh_timecnt);
		DO(tzh_typecnt);
		DO(tzh_charcnt);
#undef DO
		for (i = thistimei; i < thistimelim; ++i)
			if (pass == 1)
				/*
				** Output an INT32_MIN "transition"
				** if appropriate; see above.
				*/
				puttzcode(((ats[i] < INT32_MIN) ?
					INT32_MIN : ats[i]), fp);
			else	puttzcode64(ats[i], fp);
		for (i = thistimei; i < thistimelim; ++i) {
			unsigned char	uc;

			uc = typemap[types[i]];
			(void) fwrite(&uc, sizeof uc, (size_t) 1, fp);
		}
		for (i = 0; i < typecnt; ++i)
			if (writetype[i]) {
				puttzcode(gmtoffs[i], fp);
				(void) putc(isdsts[i], fp);
				(void) putc((unsigned char) indmap[abbrinds[i]], fp);
			}
		if (thischarcnt != 0)
			(void) fwrite(thischars, sizeof thischars[0],
				(size_t) thischarcnt, fp);
		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], -gmtoffs[j]);
			} else	todo = trans[i];
			if (pass == 1)
				puttzcode(todo, fp);
			else	puttzcode64(todo, fp);
			puttzcode(corr[i], fp);
		}
		for (i = 0; i < typecnt; ++i)
			if (writetype[i])
				(void) putc(ttisstds[i], fp);
		for (i = 0; i < typecnt; ++i)
			if (writetype[i])
				(void) putc(ttisgmts[i], fp);
	}
	(void) fprintf(fp, "\n%s\n", string);
	close_file(fp, fullname);
	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 UTC 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 *const abbr, const int abbrlen, struct zone const *zp,
    const char *letters, zic_t stdoff, 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_gmtoff + stdoff);
		else if (!letters)
			letters = "%s";
		snprintf(abbr, abbrlen, format, letters);
	} else if (stdoff != 0) {
		(void) strlcpy(abbr, slashp + 1, abbrlen);
	} else {
		(void) 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] = '>';
	for ( ; len > 0; --len)
		abbr[len] = abbr[len - 1];
	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, zic_t offset)
{
	int	hours;
	int	minutes;
	int	seconds;
	bool negative = offset < 0;
	int len = negative;

	result[0] = '\0';
	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 += sprintf(result + len, "%d", hours);
	if (minutes != 0 || seconds != 0) {
		len += sprintf(result + len, ":%02d", minutes);
		if (seconds != 0)
			len += sprintf(result + len, ":%02d", seconds);
	}
	return len;
}

static int
stringrule(char *result, const struct rule *const rp, const zic_t dstoff,
    const zic_t gmtoff)
{
	zic_t	tod = rp->r_tod;
	int	compat = 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)
		  result += sprintf(result, "%d", total + rp->r_dayofmonth - 1);
		else
		  result += sprintf(result, "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;
		result += sprintf(result, "M%d.%d.%d",
			rp->r_month + 1, week, wday);
	}
	if (rp->r_todisgmt)
		tod += gmtoff;
	if (rp->r_todisstd && rp->r_stdoff == 0)
		tod += dstoff;
	if (tod != 2 * SECSPERMIN * MINSPERHOUR) {
		*result++ = '/';
		if (! stringoffset(result, 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_month - b->r_month != 0)
		return a->r_month - b->r_month;
	return a->r_dayofmonth - b->r_dayofmonth;
}

enum { YEAR_BY_YEAR_ZONE = 1 };

static int
stringzone(char *result, const int resultlen, const struct zone *const zpfirst,
    const int zonecount)
{
	const struct zone *	zp;
	struct rule *		rp;
	struct rule *		stdrp;
	struct rule *		dstrp;
	int			i;
	const char *		abbrvar;
	int			compat = 0;
	int			c;
	size_t			len;
	int			offsetlen;
	struct rule		stdr, dstr;

	result[0] = '\0';
	zp = zpfirst + zonecount - 1;
	stdrp = dstrp = NULL;
	for (i = 0; i < zp->z_nrules; ++i) {
		rp = &zp->z_rules[i];
		if (rp->r_hiwasnum || rp->r_hiyear != ZIC_MAX)
			continue;
		if (rp->r_yrtype != NULL)
			continue;
		if (rp->r_stdoff == 0) {
			if (stdrp == NULL)
				stdrp = rp;
			else	return -1;
		} else {
			if (dstrp == NULL)
				dstrp = rp;
			else	return -1;
		}
	}
	if (stdrp == NULL && dstrp == NULL) {
		/*
		** There are no rules running through "max".
		** Find the latest std rule in stdabbrrp
		** and latest rule of any type in stdrp.
		*/
		struct rule *stdabbrrp = NULL;
		for (i = 0; i < zp->z_nrules; ++i) {
			rp = &zp->z_rules[i];
			if (rp->r_stdoff == 0 && rule_cmp(stdabbrrp, rp) < 0)
				stdabbrrp = rp;
			if (rule_cmp(stdrp, rp) < 0)
				stdrp = rp;
		}
		/*
		** Horrid special case: if year is 2037,
		** presume this is a zone handled on a year-by-year basis;
		** do not try to apply a rule to the zone.
		*/
		if (stdrp != NULL && stdrp->r_hiyear == 2037)
			return YEAR_BY_YEAR_ZONE;

		if (stdrp != NULL && stdrp->r_stdoff != 0) {
			/* Perpetual DST.  */
			dstr.r_month = TM_JANUARY;
			dstr.r_dycode = DC_DOM;
			dstr.r_dayofmonth = 1;
			dstr.r_tod = 0;
			dstr.r_todisstd = dstr.r_todisgmt = false;
			dstr.r_stdoff = stdrp->r_stdoff;
			dstr.r_abbrvar = stdrp->r_abbrvar;
			stdr.r_month = TM_DECEMBER;
			stdr.r_dycode = DC_DOM;
			stdr.r_dayofmonth = 31;
			stdr.r_tod = SECSPERDAY + stdrp->r_stdoff;
			stdr.r_todisstd = stdr.r_todisgmt = false;
			stdr.r_stdoff = 0;
			stdr.r_abbrvar
			  = (stdabbrrp ? stdabbrrp->r_abbrvar : "");
			dstrp = &dstr;
			stdrp = &stdr;
		}
	}
	if (stdrp == NULL && (zp->z_nrules != 0 || zp->z_stdoff != 0))
		return -1;
	abbrvar = (stdrp == NULL) ? "" : stdrp->r_abbrvar;
	len = doabbr(result, resultlen, zp, abbrvar, 0, true);
	offsetlen = stringoffset(result + len, -zp->z_gmtoff);
	if (! offsetlen) {
		result[0] = '\0';
		return -1;
	}
	len += offsetlen;
	if (dstrp == NULL)
		return compat;
	len += doabbr(result + len, resultlen - len,
		zp, dstrp->r_abbrvar, dstrp->r_stdoff, true);
	if (dstrp->r_stdoff != SECSPERMIN * MINSPERHOUR) {
		offsetlen = stringoffset(result + len,
		   -(zp->z_gmtoff + dstrp->r_stdoff));
		if (! offsetlen) {
			result[0] = '\0';
			return -1;
		}
		len += offsetlen;
	}
	result[len++] = ',';
	c = stringrule(result + len, dstrp, dstrp->r_stdoff, zp->z_gmtoff);
	if (c < 0) {
		result[0] = '\0';
		return -1;
	}
	if (compat < c)
		compat = c;
	len += strlen(result + len);
	result[len++] = ',';
	c = stringrule(result + len, stdrp, dstrp->r_stdoff, zp->z_gmtoff);
	if (c < 0) {
		result[0] = '\0';
		return -1;
	}
	if (compat < c)
		compat = c;
	return compat;
}

static void
outzone(const struct zone *const zpfirst, const int zonecount)
{
	const struct zone *	zp;
	struct rule *		rp;
	int			i, j;
	bool			usestart, useuntil;
	zic_t			starttime, untiltime;
	zic_t			gmtoff;
	zic_t			stdoff;
	zic_t			year;
	zic_t			startoff;
	bool			startttisstd;
	bool			startttisgmt;
	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;
	int			version;
	ptrdiff_t lastatmax = -1;

	max_abbr_len = 2 + max_format_len + max_abbrvar_len;
	max_envvar_len = 2 * max_abbr_len + 5 * 9;
	startbuf = emalloc(max_abbr_len + 1);
	ab = emalloc(max_abbr_len + 1);
	envvar = emalloc(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;
	startttisgmt = 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 ? ZIC_VERSION_PRE_2013 : ZIC_VERSION;
	do_extend = compat < 0 || compat == YEAR_BY_YEAR_ZONE;
	if (noise) {
		if (!*envvar)
			warning("%s %s",
				_("no POSIX environment variable for zone"),
				zpfirst->z_name);
		else if (compat != 0 && compat != YEAR_BY_YEAR_ZONE) {
			/* 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;
		}
	}
	/*
	** For the benefit of older systems,
	** generate data from 1900 through 2037.
	*/
	if (min_year > 1900)
		min_year = 1900;
	if (max_year < 2037)
		max_year = 2037;
	for (i = 0; i < zonecount; ++i) {
		/*
		** A guess that may well be corrected later.
		*/
		stdoff = 0;
		zp = &zpfirst[i];
		usestart = i > 0 && (zp - 1)->z_untiltime > early_time;
		useuntil = i < (zonecount - 1);
		if (useuntil && zp->z_untiltime <= early_time)
			continue;
		gmtoff = zp->z_gmtoff;
		eat(zp->z_filename, zp->z_linenum);
		*startbuf = '\0';
		startoff = zp->z_gmtoff;
		if (zp->z_nrules == 0) {
			stdoff = zp->z_stdoff;
			doabbr(startbuf, max_abbr_len + 1, zp,
			        NULL, stdoff, false);
			type = addtype(oadd(zp->z_gmtoff, stdoff),
				startbuf, stdoff != 0, startttisstd,
				startttisgmt);
			if (usestart) {
				addtt(starttime, type);
				usestart = false;
			} else	addtt(early_time, 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);
			*/
			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 &&
						yearistype(year, rp->r_yrtype);
				if (rp->r_todo)
					rp->r_temp = rpytime(rp, year);
			}
			for ( ; ; ) {
				int	k;
				zic_t	jtime, ktime;
				zic_t	offset;

				INITIALIZE(ktime);
				if (useuntil) {
					/*
					** Turn untiltime into UT
					** assuming the current gmtoff and
					** stdoff values.
					*/
					untiltime = zp->z_untiltime;
					if (!zp->z_untilrule.r_todisgmt)
						untiltime = tadd(untiltime,
							-gmtoff);
					if (!zp->z_untilrule.r_todisstd)
						untiltime = tadd(untiltime,
							-stdoff);
				}
				/*
				** 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_todisgmt ? 0 : gmtoff;
					if (!rp->r_todisstd)
						offset = oadd(offset, stdoff);
					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;
				stdoff = rp->r_stdoff;
				if (usestart && ktime == starttime)
					usestart = false;
				if (usestart) {
					if (ktime < starttime) {
						startoff = oadd(zp->z_gmtoff,
							stdoff);
						doabbr(startbuf,
							max_abbr_len + 1,
							zp,
							rp->r_abbrvar,
							rp->r_stdoff,
							false);
						continue;
					}
					if (*startbuf == '\0' &&
						startoff == oadd(zp->z_gmtoff,
						stdoff)) {
							doabbr(startbuf,
								max_abbr_len + 1,
								zp,
								rp->r_abbrvar,
								rp->r_stdoff,
								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_stdoff, false);
				offset = oadd(zp->z_gmtoff, rp->r_stdoff);
				type = addtype(offset, ab, rp->r_stdoff != 0,
					rp->r_todisstd, rp->r_todisgmt);
				addtt(ktime, type);
			}
		}
		if (usestart) {
			if (*startbuf == '\0' &&
				zp->z_format != NULL &&
				strchr(zp->z_format, '%') == NULL &&
				strchr(zp->z_format, '/') == NULL)
					(void)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	addtt(starttime,
					addtype(startoff, startbuf,
						startoff != zp->z_gmtoff,
						startttisstd,
						startttisgmt));
		}
		/*
		** Now we may get to set starttime for the next zone line.
		*/
		if (useuntil) {
			startttisstd = zp->z_untilrule.r_todisstd;
			startttisgmt = zp->z_untilrule.r_todisgmt;
			starttime = zp->z_untiltime;
			if (!startttisstd)
				starttime = tadd(starttime, -stdoff);
			if (!startttisgmt)
				starttime = tadd(starttime, -gmtoff);
		}
	}
	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[0], i = 1; i < timecnt; i++)
			if (attypes[i].at > lastat->at)
				lastat = &attypes[i];
		if (lastat->at < rpytime(&xr, max_year - 1)) {
			addtt(rpytime(&xr, max_year + 1), typecnt-1);
			attypes[timecnt - 1].dontmerge = true;
		}
	}
	writezone(zpfirst->z_name, envvar, version);
	free(startbuf);
	free(ab);
	free(envvar);
}

static void
addtt(const zic_t starttime, int type)
{
	if (starttime <= early_time ||
		(timecnt == 1 && attypes[0].at < early_time)) {
		gmtoffs[0] = gmtoffs[type];
		isdsts[0] = isdsts[type];
		ttisstds[0] = ttisstds[type];
		ttisgmts[0] = ttisgmts[type];
		if (abbrinds[type] != 0)
			strcpy(chars, &chars[abbrinds[type]]);
		abbrinds[0] = 0;
		charcnt = strlen(chars) + 1;
		typecnt = 1;
		timecnt = 0;
		type = 0;
	}
	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 gmtoff, char *const abbr, bool isdst, bool ttisstd, bool ttisgmt)
{
	int	i, j;

	/*
	** See if there's already an entry for this zone type.
	** If so, just return its index.
	*/
	for (i = 0; i < typecnt; ++i) {
		if (gmtoff == gmtoffs[i] && isdst == isdsts[i] &&
			strcmp(abbr, &chars[abbrinds[i]]) == 0 &&
			ttisstd == ttisstds[i] &&
			ttisgmt == ttisgmts[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);
	}
	if (! (-1L - 2147483647L <= gmtoff && gmtoff <= 2147483647L)) {
		error(_("UT offset out of range"));
		exit(EXIT_FAILURE);
	}
	gmtoffs[i] = gmtoff;
	isdsts[i] = isdst;
	ttisstds[i] = ttisstd;
	ttisgmts[i] = ttisgmt;

	for (j = 0; j < charcnt; ++j)
		if (strcmp(&chars[j], abbr) == 0)
			break;
	if (j == charcnt)
		newabbr(abbr);
	abbrinds[i] = j;
	++typecnt;
	return i;
}

static void
leapadd(zic_t t, bool positive, int rolling, int count)
{
	int	i, j;

	if (leapcnt + (positive ? count : 1) > TZ_MAX_LEAPS) {
		error(_("too many leap seconds"));
		exit(EXIT_FAILURE);
	}
	for (i = 0; i < leapcnt; ++i)
		if (t <= trans[i]) {
			if (t == trans[i]) {
				error(_("repeated leap second moment"));
				exit(EXIT_FAILURE);
			}
			break;
		}
	do {
		for (j = leapcnt; j > i; --j) {
			trans[j] = trans[j - 1];
			corr[j] = corr[j - 1];
			roll[j] = roll[j - 1];
		}
		trans[i] = t;
		corr[i] = positive ? 1 : -count;
		roll[i] = rolling;
		++leapcnt;
	} while (positive && --count != 0);
}

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

	/*
	** propagate leap seconds forward
	*/
	for (i = 0; i < leapcnt; ++i) {
		trans[i] = tadd(trans[i], last);
		last = corr[i] += last;
	}
}

static bool
yearistype(const int year, const char *const type)
{
	static char *	buf;
	int		result;

	if (type == NULL || *type == '\0')
		return true;
	buf = erealloc(buf, 132 + strlen(yitcommand) + strlen(type));
	(void)sprintf(buf, "%s %d %s", yitcommand, year, type); /* XXX: sprintf is safe */
	result = system(buf);
	if (WIFEXITED(result)) switch (WEXITSTATUS(result)) {
		case 0:
			return true;
		case 1:
			return false;
	}
	error(_("Wild result from command execution"));
	(void) fprintf(stderr, _("%s: command was '%s', result was %d\n"),
		progname, buf, result);
	for ( ; ; )
		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 0;
	  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;
}

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

	if (word == NULL || table == NULL)
		return NULL;
	/*
	** 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 (itsabbr(word, lp->l_word)) {
			if (foundlp == NULL)
				foundlp = lp;
			else	return NULL;	/* multiple inexact matches */
		}
	return foundlp;
}

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

	if (cp == NULL)
		return NULL;
	array = emalloc(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(1);
				}
		} while (*cp && *cp != '#' && !is_space(*cp));
		if (is_space(*cp))
			++cp;
		*dp = '\0';
	}
	array[nsubs] = NULL;
	return array;
}

static ATTRIBUTE_PURE zic_t
oadd(const zic_t t1, const zic_t t2)
{
	if (t1 < 0 ? t2 < ZIC_MIN - t1 : ZIC_MAX - t1 < t2) {
		error(_("time overflow"));
		exit(EXIT_FAILURE);
	}
	return t1 + t2;
}

static ATTRIBUTE_PURE zic_t
tadd(const zic_t t1, const zic_t t2)
{
	if (t1 == max_time && t2 > 0)
		return max_time;
	if (t1 == min_time && t2 < 0)
		return min_time;
	if (t1 < 0 ? t2 < min_time - t1 : max_time - t1 < t2) {
		error(_("time overflow"));
		exit(EXIT_FAILURE);
	}
	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 *const rp, const zic_t wantedy)
{
	int	m, i;
	zic_t	dayoff;			/* with a nod to Margaret O. */
	zic_t	t, y;

	if (wantedy == ZIC_MIN)
		return min_time;
	if (wantedy == ZIC_MAX)
		return max_time;
	dayoff = 0;
	m = TM_JANUARY;
	y = EPOCH_YEAR;
	while (wantedy != y) {
		if (wantedy > y) {
			i = len_years[isleap(y)];
			++y;
		} else {
			--y;
			i = -len_years[isleap(y)];
		}
		dayoff = oadd(dayoff, i);
	}
	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) {
		zic_t	wday;

#define LDAYSPERWEEK	((zic_t) DAYSPERWEEK)
		wday = EPOCH_WDAY;
		/*
		** Don't trust mod of negative numbers.
		*/
		if (dayoff >= 0)
			wday = (wday + dayoff) % LDAYSPERWEEK;
		else {
			wday -= ((-dayoff) % LDAYSPERWEEK);
			if (wday < 0)
				wday += LDAYSPERWEEK;
		}
		while (wday != rp->r_wday)
			if (rp->r_dycode == DC_DOWGEQ) {
				dayoff = oadd(dayoff, (zic_t) 1);
				if (++wday >= LDAYSPERWEEK)
					wday = 0;
				++i;
			} else {
				dayoff = oadd(dayoff, (zic_t) -1);
				if (--wday < 0)
					wday = LDAYSPERWEEK - 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 *const string)
{
	int	i;

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

		/*
		** Want one to ZIC_MAX_ABBR_LEN_WO_WARN alphabetics
		** optionally followed by a + or - and a number from 1 to 14.
		*/
		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);
	}
	(void)strncpy(&chars[charcnt], string, sizeof(chars) - charcnt - 1);
	charcnt += i;
}

static bool
mkdirs(char *argname)
{
	char *	name;
	char *	cp;

	if (argname == NULL || *argname == '\0')
		return true;
	cp = name = ecpyalloc(argname);
	while ((cp = strchr(cp + 1, '/')) != 0) {
		*cp = '\0';
#ifdef HAVE_DOS_FILE_NAMES
		/*
		** DOS drive specifier?
		*/
		if (is_alpha(name[0]) && name[1] == ':' && name[2] == '\0') {
				*cp = '/';
				continue;
		}
#endif
		/*
		** Try to create it.  It's OK if creation fails because
		** the directory already exists, perhaps because some
		** other process just created it.
		*/
		if (mkdir(name, MKDIR_UMASK) != 0) {
			int err = errno;
			if (itsdir(name) <= 0) {
				char const *e = strerror(err);
				warning(_("%s: Can't create directory"
					  " %s: %s\n"),
					progname, name, e);
				free(name);
				return false;
			}
		}
		*cp = '/';
	}
	free(name);
	return true;
}