/*
 * This file is in the public domain, so clarified as of
 * 2006-07-17 by Arthur David Olson.
 *
 * IDENTIFICATION
 *	  src/timezone/zic.c
 */

#include "postgres_fe.h"

#include <locale.h>
#include <sys/stat.h>
#include <time.h>

#include "pg_getopt.h"

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

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

typedef int64 zic_t;
#define ZIC_MIN PG_INT64_MIN
#define ZIC_MAX PG_INT64_MAX

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

#ifndef WIN32
#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
#endif
#ifndef S_ISLNK
#define S_ISLNK(m) 0
#endif

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	link(const char *fromname, const char *toname);

static void memory_exhausted(const char *msg) pg_attribute_noreturn();
static void verror(const char *string, va_list args) pg_attribute_printf(1, 0);
static void error(const char *string,...) pg_attribute_printf(1, 2);
static void warning(const char *string,...) pg_attribute_printf(1, 2);
static void usage(FILE *stream, int status) pg_attribute_noreturn();
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 *, const char *, bool);
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 **, int, bool);
static int	itsdir(const char *name);
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, int ntzones);
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);

/* 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 = true};

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 int	max_abbrvar_len = PERCENT_Z_LEN_BOUND;
static int	max_format_len;
static zic_t max_year;
static zic_t min_year;
static bool noise;
static bool print_abbrevs;
static zic_t print_cutoff;
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 void
memory_exhausted(const char *msg)
{
	fprintf(stderr, _("%s: Memory exhausted: %s\n"), progname, msg);
	exit(EXIT_FAILURE);
}

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

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

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

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

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

static void *
growalloc(void *ptr, size_t itemsize, int nitems, int *nitems_alloc)
{
	if (nitems < *nitems_alloc)
		return ptr;
	else
	{
		int			nitems_max = INT_MAX - WORK_AROUND_QTBUG_53071;

		if ((nitems_max - 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 *name, int num, const char *rname, int rnum)
{
	filename = name;
	linenum = num;
	rfilename = rname;
	rlinenum = rnum;
}

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

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

static void
error(const char *string,...)
{
	va_list		args;

	va_start(args, string);
	verror(string, args);
	va_end(args);
	errors = true;
}

static void
warning(const char *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 * dir, char const * name)
{
	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);
		exit(EXIT_FAILURE);
	}
}

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

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;

#ifndef WIN32
	umask(umask(S_IWGRP | S_IWOTH) | (S_IWGRP | S_IWOTH));
#endif   /* !WIN32 */
	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 (i = 1; i < argc; ++i)
		if (strcmp(argv[i], "--version") == 0)
		{
			printf("zic %s\n", PG_VERSION);
			close_file(stdout, NULL, NULL);
			return EXIT_SUCCESS;
		}
		else if (strcmp(argv[i], "--help") == 0)
		{
			usage(stdout, EXIT_SUCCESS);
		}
	while ((c = getopt(argc, argv, "d:l:p:L:vPsy:")) != EOF && c != -1)
		switch (c)
		{
			default:
				usage(stderr, EXIT_FAILURE);
			case 'd':
				if (directory == NULL)
					directory = strdup(optarg);
				else
				{
					fprintf(stderr,
							_("%s: More than one -d option specified\n"),
							progname);
					return EXIT_FAILURE;
				}
				break;
			case 'l':
				if (lcltime == NULL)
					lcltime = strdup(optarg);
				else
				{
					fprintf(stderr,
							_("%s: More than one -l option specified\n"),
							progname);
					return EXIT_FAILURE;
				}
				break;
			case 'p':
				if (psxrules == NULL)
					psxrules = strdup(optarg);
				else
				{
					fprintf(stderr,
							_("%s: More than one -p option specified\n"),
							progname);
					return EXIT_FAILURE;
				}
				break;
			case 'y':
				if (yitcommand == NULL)
					yitcommand = strdup(optarg);
				else
				{
					fprintf(stderr,
							_("%s: More than one -y option specified\n"),
							progname);
					return EXIT_FAILURE;
				}
				break;
			case 'L':
				if (leapsec == NULL)
					leapsec = strdup(optarg);
				else
				{
					fprintf(stderr,
							_("%s: More than one -L option specified\n"),
							progname);
					return EXIT_FAILURE;
				}
				break;
			case 'v':
				noise = true;
				break;
			case 'P':
				print_abbrevs = true;
				print_cutoff = time(NULL);
				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 = "data";
	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();
	change_directory(directory);
	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, false);
		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, 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};
	size_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] == '.')
	{
		error(_("file name '%s' contains '%.*s' component"),
			  name, (int) component_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(char const * fromfield, char const * tofield, bool staysymlink)
{
	int			fromisdir;
	bool		todirs_made = false;
	int			link_errno;

	/*
	 * We get to be careful here since there's a fair chance of root running
	 * us.
	 */
	fromisdir = itsdir(fromfield);
	if (fromisdir)
	{
		char const *e = strerror(fromisdir < 0 ? errno : EPERM);

		fprintf(stderr, _("%s: link from %s/%s failed: %s\n"),
				progname, directory, fromfield, e);
		exit(EXIT_FAILURE);
	}
	if (staysymlink)
		staysymlink = itsdir(tofield) == 2;
	if (remove(tofield) == 0)
		todirs_made = true;
	else if (errno != ENOENT)
	{
		char const *e = strerror(errno);

		fprintf(stderr, _("%s: Can't remove %s/%s: %s\n"),
				progname, directory, tofield, e);
		exit(EXIT_FAILURE);
	}
	link_errno = (staysymlink ? ENOTSUP
				  : link(fromfield, tofield) == 0 ? 0 : errno);
	if (link_errno == ENOENT && !todirs_made)
	{
		mkdirs(tofield, true);
		todirs_made = true;
		link_errno = link(fromfield, tofield) == 0 ? 0 : errno;
	}
	if (link_errno != 0)
	{
#ifdef HAVE_SYMLINK
		const char *s = fromfield;
		const char *t;
		char	   *p;
		size_t		dotdots = 0;
		char	   *symlinkcontents;
		int			symlink_errno;

		do
			t = s;
		while ((s = strchr(s, '/'))
			   && strncmp(fromfield, tofield, ++s - fromfield) == 0);

		for (s = tofield + (t - fromfield); *s; s++)
			dotdots += *s == '/';
		symlinkcontents = emalloc(3 * dotdots + strlen(t) + 1);
		for (p = symlinkcontents; dotdots-- != 0; p += 3)
			memcpy(p, "../", 3);
		strcpy(p, t);
		symlink_errno = symlink(symlinkcontents, tofield) == 0 ? 0 : errno;
		if (symlink_errno == ENOENT && !todirs_made)
		{
			mkdirs(tofield, true);
			symlink_errno = symlink(symlinkcontents, tofield) == 0 ? 0 : errno;
		}
		free(symlinkcontents);
		if (symlink_errno == 0)
		{
			if (link_errno != ENOTSUP)
				warning(_("symbolic link used because hard link failed: %s"),
						strerror(link_errno));
		}
		else
#endif   /* HAVE_SYMLINK */
		{
			FILE	   *fp,
					   *tp;
			int			c;

			fp = fopen(fromfield, "rb");
			if (!fp)
			{
				char const *e = strerror(errno);

				fprintf(stderr, _("%s: Can't read %s/%s: %s\n"),
						progname, directory, fromfield, e);
				exit(EXIT_FAILURE);
			}
			tp = fopen(tofield, "wb");
			if (!tp)
			{
				char const *e = strerror(errno);

				fprintf(stderr, _("%s: Can't create %s/%s: %s\n"),
						progname, directory, tofield, e);
				exit(EXIT_FAILURE);
			}
			while ((c = getc(fp)) != EOF)
				putc(c, tp);
			close_file(fp, directory, fromfield);
			close_file(tp, directory, tofield);
			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));
		}
	}
}

#define TIME_T_BITS_IN_FILE 64

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);

/*
 * 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.
 *
 * 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 (- (((zic_t) 1) << 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, 2 if a symbolic link, 0 if
   something else, -1 (setting errno) if trouble.  */
static int
itsdir(char const * name)
{
	struct stat st;
	int			res = lstat(name, &st);

	if (res == 0)
	{
#ifdef S_ISDIR
		return S_ISDIR(st.st_mode) ? 1 : S_ISLNK(st.st_mode) ? 2 : 0;
#else
		size_t		n = strlen(name);
		char	   *nameslashdot = emalloc(n + 3);
		bool		dir;

		memcpy(nameslashdot, name, n);
		strcpy(&nameslashdot[n], &"/."[!(n && name[n - 1] != '/')]);
		dir = lstat(nameslashdot, &st) == 0;
		free(nameslashdot);
		return dir;
#endif
	}
	return -1;
}

/*
 * 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)
	{
		qsort(rules, 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: Cannot open %s: %s\n"),
				progname, name, e);
		exit(EXIT_FAILURE);
	}
	wantcont = false;
	for (num = 1;; ++num)
	{
		eat(name, num);
		if (fgets(buf, 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, NULL, 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)
{
	/* PG: make hh be int not zic_t to avoid sscanf portability issues */
	int			hh;
	int			mm,
				ss,
				sign;
	char		xs;

	if (string == NULL || *string == '\0')
		return 0;
	if (!signable)
		sign = 1;
	else if (*string == '-')
	{
		sign = -1;
		++string;
	}
	else
		sign = 1;
	if (sscanf(string, "%d%c", &hh, &xs) == 1)
		mm = ss = 0;
	else if (sscanf(string, "%d:%d%c", &hh, &mm, &xs) == 2)
		ss = 0;
	else if (sscanf(string, "%d:%d:%d%c", &hh, &mm, &ss, &xs)
			 != 3)
	{
		error("%s", errstring);
		return 0;
	}
	if (hh < 0 ||
		mm < 0 || mm >= MINSPERHOUR ||
		ss < 0 || ss > SECSPERMIN)
	{
		error("%s", errstring);
		return 0;
	}
	/* Some compilers warn that this test is unsatisfiable for 32-bit ints */
#if INT_MAX > PG_INT32_MAX
	if (ZIC_MAX / SECSPERHOUR < hh)
	{
		error(_("time overflow"));
		return 0;
	}
#endif
	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 * (zic_t) hh * SECSPERHOUR,
				sign * (mm * SECSPERMIN + ss));
}

static void
inrule(char **fields, 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 **fields, 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 **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;
	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], '%')) != NULL)
	{
		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 **fields, int nfields)
{
	const char *cp;
	const struct lookup *lp;
	int			i,
				j;

	/* PG: make year be int not zic_t to avoid sscanf portability issues */
	int			year;
	int			month,
				day;
	zic_t		dayoff,
				tod;
	zic_t		t;
	char		xs;

	if (nfields != LEAP_FIELDS)
	{
		error(_("wrong number of fields on Leap line"));
		return;
	}
	dayoff = 0;
	cp = fields[LP_YEAR];
	if (sscanf(cp, "%d%c", &year, &xs) != 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, "%d%c", &day, &xs) != 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 **fields, 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 * 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;

	/* PG: year_tmp is to avoid sscanf portability issues */
	int			year_tmp;

	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, "%d%c", &year_tmp, &xs) == 1)
		rp->r_loyear = year_tmp;
	else
	{
		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, "%d%c", &year_tmp, &xs) == 1)
		rp->r_hiyear = year_tmp;
	else
	{
		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, '<')) != NULL)
			rp->r_dycode = DC_DOWLEQ;
		else if ((ep = strchr(dp, '>')) != NULL)
			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, "%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;
		}
	}
	free(dp);
}

static void
convert(const int32 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 int32 val, FILE *const fp)
{
	char		buf[4];

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

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

	convert64(val, buf);
	fwrite(buf, sizeof buf, 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 x == ((zic_t) ((int32) x));
}

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 const struct tzhead tzh0;
	static struct tzhead tzh;
	bool		dir_checked = false;
	zic_t		one = 1;
	zic_t		y2038_boundary = one << 31;
	int			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)
		qsort(attypes, 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] > PG_INT32_MIN)
	{
		--timei32;
		++timecnt32;
	}
	while (leapcnt32 > 0 && !is32(trans[leapcnt32 - 1]))
		--leapcnt32;
	while (leapcnt32 > 0 && !is32(trans[leapi32]))
	{
		--leapcnt32;
		++leapi32;
	}

	/*
	 * Remove old file, if any, to snap links.
	 */
	if (remove(name) == 0)
		dir_checked = true;
	else if (errno != ENOENT)
	{
		const char *e = strerror(errno);

		fprintf(stderr, _("%s: Cannot remove %s/%s: %s\n"),
				progname, directory, name, e);
		exit(EXIT_FAILURE);
	}
	fp = fopen(name, "wb");
	if (!fp)
	{
		int			fopen_errno = errno;

		if (fopen_errno == ENOENT && !dir_checked)
		{
			mkdirs(name, true);
			fp = fopen(name, "wb");
			fopen_errno = errno;
		}
		if (!fp)
		{
			fprintf(stderr, _("%s: Cannot create %s/%s: %s\n"),
					progname, directory, name, strerror(fopen_errno));
			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;
		int			indmap[TZ_MAX_CHARS];

		if (pass == 1)
		{
			thistimei = timei32;
			thistimecnt = timecnt32;
			thisleapi = leapi32;
			thisleapcnt = leapcnt32;
		}
		else
		{
			thistimei = 0;
			thistimecnt = timecnt;
			thisleapi = 0;
			thisleapcnt = leapcnt;
		}
		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 (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 < 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)
			{
				strcpy(&thischars[(int) thischarcnt],
					   thisabbr);
				thischarcnt += strlen(thisabbr) + 1;
			}
			indmap[abbrinds[i]] = j;
		}
#define DO(field)	fwrite(tzh.field, sizeof tzh.field, 1, fp)
		tzh = tzh0;
		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] < PG_INT32_MIN) ?
						   PG_INT32_MIN : ats[i]), fp);
			else
			{
				puttzcode64(ats[i], fp);

				/* Print current timezone abbreviations if requested */
				if (print_abbrevs &&
					(i == thistimelim - 1 || ats[i + 1] > print_cutoff))
				{
					unsigned char tm = typemap[types[i]];
					char	   *thisabbrev = &thischars[indmap[abbrinds[tm]]];

					/* filter out assorted junk entries */
					if (strcmp(thisabbrev, GRANDPARENTED) != 0 &&
						strcmp(thisabbrev, "zzz") != 0)
						fprintf(stdout, "%s\t" INT64_FORMAT "%s\n",
								thisabbrev,
								gmtoffs[tm],
								isdsts[tm] ? "\tD" : "");
				}
			}
		for (i = thistimei; i < thistimelim; ++i)
		{
			unsigned char uc;

			uc = typemap[types[i]];
			fwrite(&uc, sizeof uc, 1, fp);
		}
		for (i = 0; i < typecnt; ++i)
			if (writetype[i])
			{
				puttzcode(gmtoffs[i], fp);
				putc(isdsts[i], fp);
				putc((unsigned char) indmap[abbrinds[i]], fp);
			}
		if (thischarcnt != 0)
			fwrite(thischars, sizeof thischars[0],
				   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])
				putc(ttisstds[i], fp);
		for (i = 0; i < typecnt; ++i)
			if (writetype[i])
				putc(ttisgmts[i], fp);
	}
	fprintf(fp, "\n%s\n", string);
	close_file(fp, directory, 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 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 *abbr, struct zone const * zp, char const * 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";
		sprintf(abbr, format, letters);
	}
	else if (stdoff != 0)
	{
		strcpy(abbr, slashp + 1);
	}
	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, 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 += 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 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, 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, 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 * zpfirst, 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;
	int			max_abbr_len;
	int			max_envvar_len;
	bool		prodstic;		/* all rules are min to max */
	int			compat;
	bool		do_extend;
	char		version;
	int			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, 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, 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 = 0;
					zic_t		offset;

					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, zp,
								   rp->r_abbrvar,
								   rp->r_stdoff,
								   false);
							continue;
						}
						if (*startbuf == '\0' &&
							startoff == oadd(zp->z_gmtoff, stdoff))
						{
							doabbr(startbuf,
								   zp,
								   rp->r_abbrvar,
								   rp->r_stdoff,
								   false);
						}
					}
					eats(zp->z_filename, zp->z_linenum,
						 rp->r_filename, rp->r_linenum);
					doabbr(ab, 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);
					if (rp->r_hiyear == ZIC_MAX
						&& !(0 <= lastatmax
							 && ktime < attypes[lastatmax].at))
						lastatmax = timecnt;
					addtt(ktime, type);
				}
			}
		if (usestart)
		{
			if (*startbuf == '\0' &&
				zp->z_format != NULL &&
				strchr(zp->z_format, '%') == NULL &&
				strchr(zp->z_format, '/') == NULL)
				strcpy(startbuf, zp->z_format);
			eat(zp->z_filename, zp->z_linenum);
			if (*startbuf == '\0')
				error(_("cannot 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;

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

	if (type == NULL || *type == '\0')
		return true;
	buf = erealloc(buf, 132 + strlen(yitcommand) + strlen(type));
	sprintf(buf, "%s %d %s", yitcommand, year, type);
	result = system(buf);
	if (WIFEXITED(result))
		switch (WEXITSTATUS(result))
		{
			case 0:
				return true;
			case 1:
				return false;
		}
	error(_("Wild result from command execution"));
	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 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 bool
ciequal(const char *ap, const char *bp)
{
	while (lowerit(*ap) == lowerit(*bp++))
		if (*ap++ == '\0')
			return true;
	return false;
}

static 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 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;

	/*
	 * 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 void
time_overflow(void)
{
	error(_("time overflow"));
	exit(EXIT_FAILURE);
}

static 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 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;

	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, 1);
				if (++wday >= LDAYSPERWEEK)
					wday = 0;
				++i;
			}
			else
			{
				dayoff = oadd(dayoff, -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 *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);
	}
	strcpy(&chars[charcnt], string);
	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.  */
static void
mkdirs(char const * argname, bool ancestors)
{
	char	   *name;
	char	   *cp;

	cp = name = ecpyalloc(argname);

	/* Do not mkdir a root directory, as it must exist.  */
#ifdef WIN32
	if (is_alpha(name[0]) && name[1] == ':')
		cp += 2;
#endif
	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)
		{
			int			err = errno;

			if (err != EEXIST && itsdir(name) < 0)
			{
				error(_("%s: Cannot create directory %s: %s"),
					  progname, name, strerror(err));
				exit(EXIT_FAILURE);
			}
		}
		if (cp)
			*cp++ = '/';
	}
	free(name);
}


#ifdef WIN32
/*
 * To run on win32
 */
int
link(const char *oldpath, const char *newpath)
{
	if (!CopyFile(oldpath, newpath, false))
	{
		_dosmaperr(GetLastError());
		return -1;
	}
	return 0;
}
#endif
