vendor/tzcode/tzcode2022c

1 files changed, 2296 insertions, 1377 deletions

diff --git a/zic.c b/zic.c
index a75d8c75e88c..ff0479374515 100644
--- a/zic.c
+++ b/zic.c
@@ -1,59 +1,82 @@
+/* Compile .zi time zone data into TZif binary files.  */
+
 /*
 ** This file is in the public domain, so clarified as of
 ** 2006-07-17 by Arthur David Olson.
 */
 
-static char	elsieid[] = "@(#)zic.c	8.24";
+/* Use the system 'time' function, instead of any private replacement.
+   This avoids creating an unnecessary dependency on localtime.c.  */
+#undef EPOCH_LOCAL
+#undef EPOCH_OFFSET
+#undef RESERVE_STD_EXT_IDS
+#undef time_tz
 
+#include "version.h"
 #include "private.h"
-#include "locale.h"
 #include "tzfile.h"
 
-#define	ZIC_VERSION	'2'
+#include <fcntl.h>
+#include <locale.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
 
 typedef int_fast64_t	zic_t;
+#define ZIC_MIN INT_FAST64_MIN
+#define ZIC_MAX INT_FAST64_MAX
+#define SCNdZIC SCNdFAST64
 
 #ifndef ZIC_MAX_ABBR_LEN_WO_WARN
-#define ZIC_MAX_ABBR_LEN_WO_WARN	6
+# define ZIC_MAX_ABBR_LEN_WO_WARN 6
 #endif /* !defined ZIC_MAX_ABBR_LEN_WO_WARN */
 
+#ifdef HAVE_DIRECT_H
+# include <direct.h>
+# include <io.h>
+# undef mkdir
+# define mkdir(name, mode) _mkdir(name)
+#endif
+
 #if HAVE_SYS_STAT_H
-#include "sys/stat.h"
+# 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)
+# define MKDIR_UMASK (S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
 #else
-#define MKDIR_UMASK 0755
+# define MKDIR_UMASK 0755
 #endif
 
-/*
-** On some ancient hosts, predicates like `isspace(C)' are defined
-** only if isascii(C) || C == EOF. Modern hosts obey the C Standard,
-** which says they are defined only if C == ((unsigned char) C) || C == EOF.
-** Neither the C Standard nor Posix require that `isascii' exist.
-** For portability, we check both ancient and modern requirements.
-** If isascii is not defined, the isascii check succeeds trivially.
-*/
-#include "ctype.h"
-#ifndef isascii
-#define isascii(x) 1
+/* The maximum ptrdiff_t value, for pre-C99 platforms.  */
+#ifndef PTRDIFF_MAX
+static ptrdiff_t const PTRDIFF_MAX = MAXVAL(ptrdiff_t, TYPE_BIT(ptrdiff_t));
+#endif
+
+/* The minimum alignment of a type, for pre-C11 platforms.  */
+#if __STDC_VERSION__ < 201112
+# define _Alignof(type) offsetof(struct { char a; type b; }, b)
 #endif
 
-#define OFFSET_STRLEN_MAXIMUM	(7 + INT_STRLEN_MAXIMUM(long))
-#define RULE_STRLEN_MAXIMUM	8	/* "Mdd.dd.d" */
+/* The maximum length of a text line, including the trailing newline.  */
+#ifndef _POSIX2_LINE_MAX
+# define _POSIX2_LINE_MAX 2048
+#endif
 
-#define end(cp)	(strchr((cp), '\0'))
+/* The type for line numbers.  Use PRIdMAX to format them; formerly
+   there was also "#define PRIdLINENO PRIdMAX" and formats used
+   PRIdLINENO, but xgettext cannot grok that.  */
+typedef intmax_t lineno;
 
 struct rule {
 	const char *	r_filename;
-	int		r_linenum;
+	lineno		r_linenum;
 	const char *	r_name;
 
-	int		r_loyear;	/* for example, 1986 */
-	int		r_hiyear;	/* for example, 1986 */
-	const char *	r_yrtype;
-	int		r_lowasnum;
-	int		r_hiwasnum;
+	zic_t		r_loyear;	/* for example, 1986 */
+	zic_t		r_hiyear;	/* for example, 1986 */
+	bool		r_lowasnum;
+	bool		r_hiwasnum;
 
 	int		r_month;	/* 0..11 */
 
@@ -61,222 +84,256 @@ struct rule {
 	int		r_dayofmonth;
 	int		r_wday;
 
-	long		r_tod;		/* time from midnight */
-	int		r_todisstd;	/* above is standard time if TRUE */
-					/* or wall clock time if FALSE */
-	int		r_todisgmt;	/* above is GMT if TRUE */
-					/* or local time if FALSE */
-	long		r_stdoff;	/* offset from standard time */
+	zic_t		r_tod;		/* time from midnight */
+	bool		r_todisstd;	/* is r_tod standard time? */
+	bool		r_todisut;	/* is r_tod UT? */
+	bool		r_isdst;	/* is this daylight saving time? */
+	zic_t		r_save;		/* offset from standard time */
 	const char *	r_abbrvar;	/* variable part of abbreviation */
 
-	int		r_todo;		/* a rule to do (used in outzone) */
+	bool		r_todo;		/* a rule to do (used in outzone) */
 	zic_t		r_temp;		/* used in outzone */
 };
 
 /*
-**	r_dycode		r_dayofmonth	r_wday
+** 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) */
+enum {
+  DC_DOM,	/* 1..31 */	/* unused */
+  DC_DOWGEQ,	/* 1..31 */	/* 0..6 (Sun..Sat) */
+  DC_DOWLEQ	/* 1..31 */	/* 0..6 (Sun..Sat) */
+};
 
 struct zone {
 	const char *	z_filename;
-	int		z_linenum;
+	lineno		z_linenum;
 
 	const char *	z_name;
-	long		z_gmtoff;
-	const char *	z_rule;
+	zic_t		z_stdoff;
+	char *		z_rule;
 	const char *	z_format;
+	char		z_format_specifier;
 
-	long		z_stdoff;
+	bool		z_isdst;
+	zic_t		z_save;
 
 	struct rule *	z_rules;
-	int		z_nrules;
+	ptrdiff_t	z_nrules;
 
 	struct rule	z_untilrule;
 	zic_t		z_untiltime;
 };
 
+#if !HAVE_POSIX_DECLS
 extern int	getopt(int argc, char * const argv[],
 			const char * options);
-extern int	link(const char * fromname, const char * toname);
+extern int	link(const char * target, const char * linkname);
 extern char *	optarg;
 extern int	optind;
+#endif
+
+#if ! HAVE_LINK
+# define link(target, linkname) (errno = ENOTSUP, -1)
+#endif
+#if ! HAVE_SYMLINK
+# define readlink(file, buf, size) (errno = ENOTSUP, -1)
+# define symlink(target, linkname) (errno = ENOTSUP, -1)
+# define S_ISLNK(m) 0
+#endif
+#ifndef AT_SYMLINK_FOLLOW
+# define linkat(targetdir, target, linknamedir, linkname, flag) \
+    (itssymlink(target) ? (errno = ENOTSUP, -1) : link(target, linkname))
+#endif
 
 static void	addtt(zic_t starttime, int type);
-static int	addtype(long gmtoff, const char * abbr, int isdst,
-				int ttisstd, int ttisgmt);
-static void	leapadd(zic_t t, int positive, int rolling, int count);
+static int	addtype(zic_t, char const *, bool, bool, bool);
+static void	leapadd(zic_t, int, int);
 static void	adjleap(void);
 static void	associate(void);
-static int	ciequal(const char * ap, const char * bp);
-static void	convert(long val, char * buf);
-static void	convert64(zic_t val, char * buf);
-static void	dolink(const char * fromfield, const char * tofield);
-static void	doabbr(char * abbr, const char * format,
-			const char * letters, int isdst, int doquotes);
-static void	eat(const char * name, int num);
-static void	eats(const char * name, int num,
-			const char * rname, int rnum);
-static long	eitol(int i);
-static void	error(const char * message);
-static char **	getfields(char * buf);
-static long	gethms(const char * string, const char * errstrng,
-			int signable);
+static void	dolink(const char *, const char *, bool);
+static int	getfields(char *, char **, int);
+static zic_t	gethms(const char * string, const char * errstring);
+static zic_t	getsave(char *, bool *);
+static void	inexpires(char **, int);
 static void	infile(const char * filename);
 static void	inleap(char ** fields, int nfields);
 static void	inlink(char ** fields, int nfields);
 static void	inrule(char ** fields, int nfields);
-static int	inzcont(char ** fields, int nfields);
-static int	inzone(char ** fields, int nfields);
-static int	inzsub(char ** fields, int nfields, int iscont);
-static int	is32(zic_t x);
-static int	itsabbr(const char * abbr, const char * word);
-static int	itsdir(const char * name);
-static int	lowerit(int c);
-static char *	memcheck(char * tocheck);
-static int	mkdirs(char * filename);
+static bool	inzcont(char ** fields, int nfields);
+static bool	inzone(char ** fields, int nfields);
+static bool	inzsub(char **, int, bool);
+static bool	itssymlink(char const *);
+static bool	is_alpha(char a);
+static char	lowerit(char);
+static void	mkdirs(char const *, bool);
 static void	newabbr(const char * abbr);
-static long	oadd(long t1, long t2);
-static void	outzone(const struct zone * zp, int ntzones);
-static void	puttzcode(long code, FILE * fp);
-static void	puttzcode64(zic_t code, FILE * fp);
-static int	rcomp(const void * leftp, const void * rightp);
-static zic_t	rpytime(const struct rule * rp, int wantedy);
-static void	rulesub(struct rule * rp,
+static zic_t	oadd(zic_t t1, zic_t t2);
+static void	outzone(const struct zone * zp, ptrdiff_t ntzones);
+static zic_t	rpytime(const struct rule * rp, zic_t wantedy);
+static bool	rulesub(struct rule * rp,
 			const char * loyearp, const char * hiyearp,
 			const char * typep, const char * monthp,
 			const char * dayp, const char * timep);
-static int 	stringoffset(char * result, long offset);
-static int	stringrule(char * result, const struct rule * rp,
-			long dstoff, long gmtoff);
-static void 	stringzone(char * result,
-			const struct zone * zp, int ntzones);
-static void	setboundaries(void);
-static zic_t	tadd(zic_t t1, long t2);
-static void	usage(FILE *stream, int status);
-static void	writezone(const char * name, const char * string);
-static int	yearistype(int year, const char * type);
+static zic_t	tadd(zic_t t1, zic_t t2);
+
+/* Bound on length of what %z can expand to.  */
+enum { PERCENT_Z_LEN_BOUND = sizeof "+995959" - 1 };
+
+/* If true, work around a bug in Qt 5.6.1 and earlier, which mishandles
+   TZif files whose POSIX-TZ-style strings contain '<'; see
+   QTBUG-53071 <https://bugreports.qt.io/browse/QTBUG-53071>.  This
+   workaround will no longer be needed when Qt 5.6.1 and earlier are
+   obsolete, say in the year 2021.  */
+#ifndef WORK_AROUND_QTBUG_53071
+enum { WORK_AROUND_QTBUG_53071 = true };
+#endif
 
 static int		charcnt;
-static int		errors;
+static bool		errors;
+static bool		warnings;
 static const char *	filename;
 static int		leapcnt;
-static int		leapseen;
-static int		leapminyear;
-static int		leapmaxyear;
-static int		linenum;
-static int		max_abbrvar_len;
+static bool		leapseen;
+static zic_t		leapminyear;
+static zic_t		leapmaxyear;
+static lineno		linenum;
+static int		max_abbrvar_len = PERCENT_Z_LEN_BOUND;
 static int		max_format_len;
-static zic_t		max_time;
-static int		max_year;
-static zic_t		min_time;
-static int		min_year;
-static int		noise;
+static zic_t		max_year;
+static zic_t		min_year;
+static bool		noise;
 static const char *	rfilename;
-static int		rlinenum;
+static lineno		rlinenum;
 static const char *	progname;
-static int		timecnt;
+static ptrdiff_t	timecnt;
+static ptrdiff_t	timecnt_alloc;
 static int		typecnt;
+static int		unspecifiedtype;
 
 /*
 ** Line codes.
 */
 
-#define LC_RULE		0
-#define LC_ZONE		1
-#define LC_LINK		2
-#define LC_LEAP		3
+enum {
+  LC_RULE,
+  LC_ZONE,
+  LC_LINK,
+  LC_LEAP,
+  LC_EXPIRES
+};
 
 /*
 ** 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
+enum {
+  ZF_NAME = 1,
+  ZF_STDOFF,
+  ZF_RULE,
+  ZF_FORMAT,
+  ZF_TILYEAR,
+  ZF_TILMONTH,
+  ZF_TILDAY,
+  ZF_TILTIME,
+  ZONE_MAXFIELDS,
+  ZONE_MINFIELDS = ZF_TILYEAR
+};
 
 /*
 ** 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
+enum {
+  ZFC_STDOFF,
+  ZFC_RULE,
+  ZFC_FORMAT,
+  ZFC_TILYEAR,
+  ZFC_TILMONTH,
+  ZFC_TILDAY,
+  ZFC_TILTIME,
+  ZONEC_MAXFIELDS,
+  ZONEC_MINFIELDS = ZFC_TILYEAR
+};
 
 /*
 ** 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
+enum {
+  RF_NAME = 1,
+  RF_LOYEAR,
+  RF_HIYEAR,
+  RF_COMMAND,
+  RF_MONTH,
+  RF_DAY,
+  RF_TOD,
+  RF_SAVE,
+  RF_ABBRVAR,
+  RULE_FIELDS
+};
 
 /*
 ** Which fields are which on a Link line.
 */
 
-#define LF_FROM		1
-#define LF_TO		2
-#define LINK_FIELDS	3
+enum {
+  LF_TARGET = 1,
+  LF_LINKNAME,
+  LINK_FIELDS
+};
 
 /*
 ** 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
+enum {
+  LP_YEAR = 1,
+  LP_MONTH,
+  LP_DAY,
+  LP_TIME,
+  LP_CORR,
+  LP_ROLL,
+  LEAP_FIELDS,
+
+  /* Expires lines are like Leap lines, except without CORR and ROLL fields.  */
+  EXPIRES_FIELDS = LP_TIME + 1
+};
+
+/* The maximum number of fields on any of the above lines.
+   (The "+"s pacify gcc -Wenum-compare.)  */
+enum {
+  MAX_FIELDS = max(max(+RULE_FIELDS, +LINK_FIELDS),
+		   max(+LEAP_FIELDS, +EXPIRES_FIELDS))
+};
 
 /*
 ** Year synonyms.
 */
 
-#define YR_MINIMUM	0
-#define YR_MAXIMUM	1
-#define YR_ONLY		2
+enum {
+  YR_MINIMUM,
+  YR_MAXIMUM,
+  YR_ONLY
+};
 
 static struct rule *	rules;
-static int		nrules;	/* number of rules */
+static ptrdiff_t	nrules;	/* number of rules */
+static ptrdiff_t	nrules_alloc;
 
 static struct zone *	zones;
-static int		nzones;	/* number of zones */
+static ptrdiff_t	nzones;	/* number of zones */
+static ptrdiff_t	nzones_alloc;
 
 struct link {
 	const char *	l_filename;
-	int		l_linenum;
-	const char *	l_from;
-	const char *	l_to;
+	lineno		l_linenum;
+	const char *	l_target;
+	const char *	l_linkname;
 };
 
 static struct link *	links;
-static int		nlinks;
+static ptrdiff_t	nlinks;
+static ptrdiff_t	nlinks_alloc;
 
 struct lookup {
 	const char *	l_word;
@@ -286,11 +343,15 @@ struct lookup {
 static struct lookup const *	byword(const char * string,
 					const struct lookup * lp);
 
-static struct lookup const	line_codes[] = {
+static struct lookup const zi_line_codes[] = {
 	{ "Rule",	LC_RULE },
 	{ "Zone",	LC_ZONE },
 	{ "Link",	LC_LINK },
+	{ NULL,		0 }
+};
+static struct lookup const leap_line_codes[] = {
 	{ "Leap",	LC_LEAP },
+	{ "Expires",	LC_EXPIRES },
 	{ NULL,		0}
 };
 
@@ -346,8 +407,8 @@ static struct lookup const	end_years[] = {
 };
 
 static struct lookup const	leap_types[] = {
-	{ "Rolling",	TRUE },
-	{ "Stationary",	FALSE },
+	{ "Rolling",	true },
+	{ "Stationary",	false },
 	{ NULL,		0 }
 };
 
@@ -362,51 +423,104 @@ static const int	len_years[2] = {
 
 static struct attype {
 	zic_t		at;
+	bool		dontmerge;
 	unsigned char	type;
-}			attypes[TZ_MAX_TIMES];
-static long		gmtoffs[TZ_MAX_TYPES];
+} *			attypes;
+static zic_t		utoffs[TZ_MAX_TYPES];
 static char		isdsts[TZ_MAX_TYPES];
-static unsigned char	abbrinds[TZ_MAX_TYPES];
-static char		ttisstds[TZ_MAX_TYPES];
-static char		ttisgmts[TZ_MAX_TYPES];
+static unsigned char	desigidx[TZ_MAX_TYPES];
+static bool		ttisstds[TZ_MAX_TYPES];
+static bool		ttisuts[TZ_MAX_TYPES];
 static char		chars[TZ_MAX_CHARS];
 static zic_t		trans[TZ_MAX_LEAPS];
-static long		corr[TZ_MAX_LEAPS];
+static zic_t		corr[TZ_MAX_LEAPS];
 static char		roll[TZ_MAX_LEAPS];
 
 /*
 ** Memory allocation.
 */
 
+static _Noreturn void
+memory_exhausted(const char *msg)
+{
+	fprintf(stderr, _("%s: Memory exhausted: %s\n"), progname, msg);
+	exit(EXIT_FAILURE);
+}
+
+static ATTRIBUTE_PURE size_t
+size_product(size_t nitems, size_t itemsize)
+{
+	if (SIZE_MAX / itemsize < nitems)
+		memory_exhausted(_("size overflow"));
+	return nitems * itemsize;
+}
+
+static ATTRIBUTE_PURE size_t
+align_to(size_t size, size_t alignment)
+{
+  size_t aligned_size = size + alignment - 1;
+  aligned_size -= aligned_size % alignment;
+  if (aligned_size < size)
+    memory_exhausted(_("alignment overflow"));
+  return aligned_size;
+}
+
+#if !HAVE_STRDUP
 static char *
-memcheck(ptr)
-char * const	ptr;
+strdup(char const *str)
 {
-	if (ptr == NULL) {
-		const char *e = strerror(errno);
+  char *result = malloc(strlen(str) + 1);
+  return result ? strcpy(result, str) : result;
+}
+#endif
 
-		(void) fprintf(stderr, _("%s: Memory exhausted: %s\n"),
-			progname, e);
-		exit(EXIT_FAILURE);
-	}
+static void *
+memcheck(void *ptr)
+{
+	if (ptr == NULL)
+	  memory_exhausted(strerror(HAVE_MALLOC_ERRNO ? errno : ENOMEM));
 	return ptr;
 }
 
-#define emalloc(size)		memcheck(imalloc(size))
-#define erealloc(ptr, size)	memcheck(irealloc((ptr), (size)))
-#define ecpyalloc(ptr)		memcheck(icpyalloc(ptr))
-#define ecatalloc(oldp, newp)	memcheck(icatalloc((oldp), (newp)))
+static void * ATTRIBUTE_MALLOC
+emalloc(size_t size)
+{
+  return memcheck(malloc(size));
+}
+
+static void *
+erealloc(void *ptr, size_t size)
+{
+  return memcheck(realloc(ptr, size));
+}
+
+static char * ATTRIBUTE_MALLOC
+ecpyalloc(char const *str)
+{
+  return memcheck(strdup(str));
+}
+
+static void *
+growalloc(void *ptr, size_t itemsize, ptrdiff_t nitems, ptrdiff_t *nitems_alloc)
+{
+	if (nitems < *nitems_alloc)
+		return ptr;
+	else {
+		ptrdiff_t nitems_max = PTRDIFF_MAX - WORK_AROUND_QTBUG_53071;
+		ptrdiff_t amax = min(nitems_max, SIZE_MAX);
+		if ((amax - 1) / 3 * 2 < *nitems_alloc)
+			memory_exhausted(_("integer overflow"));
+		*nitems_alloc += (*nitems_alloc >> 1) + 1;
+		return erealloc(ptr, size_product(*nitems_alloc, itemsize));
+	}
+}
 
 /*
 ** Error handling.
 */
 
 static void
-eats(name, num, rname, rnum)
-const char * const	name;
-const int		num;
-const char * const	rname;
-const int		rnum;
+eats(char const *name, lineno num, char const *rname, lineno rnum)
 {
 	filename = name;
 	linenum = num;
@@ -415,174 +529,411 @@ const int		rnum;
 }
 
 static void
-eat(name, num)
-const char * const	name;
-const int		num;
+eat(char const *name, lineno num)
 {
-	eats(name, num, (char *) NULL, -1);
+	eats(name, num, NULL, -1);
 }
 
-static void
-error(string)
-const char * const	string;
+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.
 	*/
-	(void) fprintf(stderr, _("\"%s\", line %d: %s"),
-		filename, linenum, string);
+	if (filename)
+	  fprintf(stderr, _("\"%s\", line %"PRIdMAX": "), filename, linenum);
+	vfprintf(stderr, string, args);
 	if (rfilename != NULL)
-		(void) fprintf(stderr, _(" (rule from \"%s\", line %d)"),
+		fprintf(stderr, _(" (rule from \"%s\", line %"PRIdMAX")"),
 			rfilename, rlinenum);
-	(void) fprintf(stderr, "\n");
-	++errors;
+	fprintf(stderr, "\n");
 }
 
-static void
-warning(string)
-const char * const	string;
+static void ATTRIBUTE_FORMAT((printf, 1, 2))
+error(const char *const string, ...)
 {
-	char *	cp;
+	va_list args;
+	va_start(args, string);
+	verror(string, args);
+	va_end(args);
+	errors = true;
+}
 
-	cp = ecpyalloc(_("warning: "));
-	cp = ecatalloc(cp, string);
-	error(cp);
-	ifree(cp);
-	--errors;
+static void ATTRIBUTE_FORMAT((printf, 1, 2))
+warning(const char *const string, ...)
+{
+	va_list args;
+	fprintf(stderr, _("warning: "));
+	va_start(args, string);
+	verror(string, args);
+	va_end(args);
+	warnings = true;
 }
 
+/* Close STREAM.  If it had an I/O error, report it against DIR/NAME,
+   remove TEMPNAME if nonnull, and then exit.  */
 static void
+close_file(FILE *stream, char const *dir, char const *name,
+	   char const *tempname)
+{
+  char const *e = (ferror(stream) ? _("I/O error")
+		   : fclose(stream) != 0 ? strerror(errno) : NULL);
+  if (e) {
+    fprintf(stderr, "%s: %s%s%s%s%s\n", progname,
+	    dir ? dir : "", dir ? "/" : "",
+	    name ? name : "", name ? ": " : "",
+	    e);
+    if (tempname)
+      remove(tempname);
+    exit(EXIT_FAILURE);
+  }
+}
+
+static _Noreturn void
 usage(FILE *stream, int status)
 {
-	(void) fprintf(stream, _("%s: usage is %s \
-[ --version ] [ --help ] [ -v ] [ -l localtime ] [ -p posixrules ] \\\n\
-\t[ -d directory ] [ -L leapseconds ] [ -y yearistype ] [ filename ... ]\n\
-\n\
-Report bugs to tz@elsie.nci.nih.gov.\n"),
-		       progname, progname);
-	exit(status);
+  fprintf(stream,
+	  _("%s: usage is %s [ --version ] [ --help ] [ -v ] \\\n"
+	    "\t[ -b {slim|fat} ] [ -d directory ] [ -l localtime ]"
+	    " [ -L leapseconds ] \\\n"
+	    "\t[ -p posixrules ] [ -r '[@lo][/@hi]' ] [ -R '@hi' ] \\\n"
+	    "\t[ -t localtime-link ] \\\n"
+	    "\t[ filename ... ]\n\n"
+	    "Report bugs to %s.\n"),
+	  progname, progname, REPORT_BUGS_TO);
+  if (status == EXIT_SUCCESS)
+    close_file(stream, NULL, NULL, NULL);
+  exit(status);
+}
+
+/* Change the working directory to DIR, possibly creating DIR and its
+   ancestors.  After this is done, all files are accessed with names
+   relative to DIR.  */
+static void
+change_directory(char const *dir)
+{
+  if (chdir(dir) != 0) {
+    int chdir_errno = errno;
+    if (chdir_errno == ENOENT) {
+      mkdirs(dir, false);
+      chdir_errno = chdir(dir) == 0 ? 0 : errno;
+    }
+    if (chdir_errno != 0) {
+      fprintf(stderr, _("%s: Can't chdir to %s: %s\n"),
+	      progname, dir, strerror(chdir_errno));
+      exit(EXIT_FAILURE);
+    }
+  }
+}
+
+/* Simple signal handling: just set a flag that is checked
+   periodically outside critical sections.  To set up the handler,
+   prefer sigaction if available to close a signal race.  */
+
+static sig_atomic_t got_signal;
+
+static void
+signal_handler(int sig)
+{
+#ifndef SA_SIGINFO
+  signal(sig, signal_handler);
+#endif
+  got_signal = sig;
+}
+
+/* Arrange for SIGINT etc. to be caught by the handler.  */
+static void
+catch_signals(void)
+{
+  static int const signals[] = {
+#ifdef SIGHUP
+    SIGHUP,
+#endif
+    SIGINT,
+#ifdef SIGPIPE
+    SIGPIPE,
+#endif
+    SIGTERM
+  };
+  int i;
+  for (i = 0; i < sizeof signals / sizeof signals[0]; i++) {
+#ifdef SA_SIGINFO
+    struct sigaction act0, act;
+    act.sa_handler = signal_handler;
+    sigemptyset(&act.sa_mask);
+    act.sa_flags = 0;
+    if (sigaction(signals[i], &act, &act0) == 0
+	&& ! (act0.sa_flags & SA_SIGINFO) && act0.sa_handler == SIG_IGN) {
+      sigaction(signals[i], &act0, NULL);
+      got_signal = 0;
+    }
+#else
+    if (signal(signals[i], signal_handler) == SIG_IGN) {
+      signal(signals[i], SIG_IGN);
+      got_signal = 0;
+    }
+#endif
+  }
+}
+
+/* If a signal has arrived, terminate zic with appropriate status.  */
+static void
+check_for_signal(void)
+{
+  int sig = got_signal;
+  if (sig) {
+    signal(sig, SIG_DFL);
+    raise(sig);
+    abort(); /* A bug in 'raise'.  */
+  }
+}
+
+enum { TIME_T_BITS_IN_FILE = 64 };
+
+/* The minimum and maximum values representable in a TZif file.  */
+static zic_t const min_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
+static zic_t const max_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);
+
+/* The minimum, and one less than the maximum, values specified by
+   the -r option.  These default to MIN_TIME and MAX_TIME.  */
+static zic_t lo_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
+static zic_t hi_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);
+
+/* The time specified by the -R option, defaulting to MIN_TIME.  */
+static zic_t redundant_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
+
+/* The time specified by an Expires line, or negative if no such line.  */
+static zic_t leapexpires = -1;
+
+/* Set the time range of the output to TIMERANGE.
+   Return true if successful.  */
+static bool
+timerange_option(char *timerange)
+{
+  intmax_t lo = min_time, hi = max_time;
+  char *lo_end = timerange, *hi_end;
+  if (*timerange == '@') {
+    errno = 0;
+    lo = strtoimax(timerange + 1, &lo_end, 10);
+    if (lo_end == timerange + 1 || (lo == INTMAX_MAX && errno == ERANGE))
+      return false;
+  }
+  hi_end = lo_end;
+  if (lo_end[0] == '/' && lo_end[1] == '@') {
+    errno = 0;
+    hi = strtoimax(lo_end + 2, &hi_end, 10);
+    if (hi_end == lo_end + 2 || hi == INTMAX_MIN)
+      return false;
+    hi -= ! (hi == INTMAX_MAX && errno == ERANGE);
+  }
+  if (*hi_end || hi < lo || max_time < lo || hi < min_time)
+    return false;
+  lo_time = max(lo, min_time);
+  hi_time = min(hi, max_time);
+  return true;
+}
+
+/* Generate redundant time stamps up to OPT.  Return true if successful.  */
+static bool
+redundant_time_option(char *opt)
+{
+  if (*opt == '@') {
+    intmax_t redundant;
+    char *opt_end;
+    redundant = strtoimax(opt + 1, &opt_end, 10);
+    if (opt_end != opt + 1 && !*opt_end) {
+      redundant_time = max(redundant_time, redundant);
+      return true;
+    }
+  }
+  return false;
 }
 
 static const char *	psxrules;
 static const char *	lcltime;
 static const char *	directory;
 static const char *	leapsec;
-static const char *	yitcommand;
+static const char *	tzdefault;
+
+/* -1 if the TZif output file should be slim, 0 if default, 1 if the
+   output should be fat for backward compatibility.  ZIC_BLOAT_DEFAULT
+   determines the default.  */
+static int bloat;
+
+static bool
+want_bloat(void)
+{
+  return 0 <= bloat;
+}
+
+#ifndef ZIC_BLOAT_DEFAULT
+# define ZIC_BLOAT_DEFAULT "slim"
+#endif
 
 int
-main(argc, argv)
-int	argc;
-char *	argv[];
+main(int argc, char **argv)
 {
-	register int	i;
-	register int	j;
-	register int	c;
+	register int c, k;
+	register ptrdiff_t i, j;
+	bool timerange_given = false;
 
-#ifdef unix
-	(void) umask(umask(S_IWGRP | S_IWOTH) | (S_IWGRP | S_IWOTH));
-#endif /* defined unix */
+#ifdef S_IWGRP
+	umask(umask(S_IWGRP | S_IWOTH) | (S_IWGRP | S_IWOTH));
+#endif
 #if HAVE_GETTEXT
-	(void) setlocale(LC_ALL, "");
-#ifdef TZ_DOMAINDIR
-	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
-#endif /* defined TEXTDOMAINDIR */
-	(void) textdomain(TZ_DOMAIN);
+	setlocale(LC_ALL, "");
+# ifdef TZ_DOMAINDIR
+	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
+# endif /* defined TEXTDOMAINDIR */
+	textdomain(TZ_DOMAIN);
 #endif /* HAVE_GETTEXT */
 	progname = argv[0];
 	if (TYPE_BIT(zic_t) < 64) {
-		(void) fprintf(stderr, "%s: %s\n", progname,
+		fprintf(stderr, "%s: %s\n", progname,
 			_("wild compilation-time specification of zic_t"));
-		exit(EXIT_FAILURE);
+		return EXIT_FAILURE;
 	}
-	for (i = 1; i < argc; ++i)
-		if (strcmp(argv[i], "--version") == 0) {
-			(void) printf("%s\n", elsieid);
-			exit(EXIT_SUCCESS);
-		} else if (strcmp(argv[i], "--help") == 0) {
+	for (k = 1; k < argc; k++)
+		if (strcmp(argv[k], "--version") == 0) {
+			printf("zic %s%s\n", PKGVERSION, TZVERSION);
+			close_file(stdout, NULL, NULL, NULL);
+			return EXIT_SUCCESS;
+		} else if (strcmp(argv[k], "--help") == 0) {
 			usage(stdout, EXIT_SUCCESS);
 		}
-	while ((c = getopt(argc, argv, "d:l:p:L:vsy:")) != EOF && c != -1)
+	while ((c = getopt(argc, argv, "b:d:l:L:p:r:R:st:vy:")) != EOF
+	       && c != -1)
 		switch (c) {
 			default:
 				usage(stderr, EXIT_FAILURE);
+			case 'b':
+				if (strcmp(optarg, "slim") == 0) {
+				  if (0 < bloat)
+				    error(_("incompatible -b options"));
+				  bloat = -1;
+				} else if (strcmp(optarg, "fat") == 0) {
+				  if (bloat < 0)
+				    error(_("incompatible -b options"));
+				  bloat = 1;
+				} else
+				  error(_("invalid option: -b '%s'"), optarg);
+				break;
 			case 'd':
 				if (directory == NULL)
 					directory = optarg;
 				else {
-					(void) fprintf(stderr,
+					fprintf(stderr,
 _("%s: More than one -d option specified\n"),
 						progname);
-					exit(EXIT_FAILURE);
+					return EXIT_FAILURE;
 				}
 				break;
 			case 'l':
 				if (lcltime == NULL)
 					lcltime = optarg;
 				else {
-					(void) fprintf(stderr,
+					fprintf(stderr,
 _("%s: More than one -l option specified\n"),
 						progname);
-					exit(EXIT_FAILURE);
+					return EXIT_FAILURE;
 				}
 				break;
 			case 'p':
 				if (psxrules == NULL)
 					psxrules = optarg;
 				else {
-					(void) fprintf(stderr,
+					fprintf(stderr,
 _("%s: More than one -p option specified\n"),
 						progname);
-					exit(EXIT_FAILURE);
+					return EXIT_FAILURE;
 				}
 				break;
-			case 'y':
-				if (yitcommand == NULL)
-					yitcommand = optarg;
-				else {
-					(void) fprintf(stderr,
-_("%s: More than one -y option specified\n"),
-						progname);
-					exit(EXIT_FAILURE);
+			case 't':
+				if (tzdefault != NULL) {
+				  fprintf(stderr,
+					  _("%s: More than one -t option"
+					    " specified\n"),
+					  progname);
+				  return EXIT_FAILURE;
 				}
+				tzdefault = optarg;
+				break;
+			case 'y':
+				warning(_("-y ignored"));
 				break;
 			case 'L':
 				if (leapsec == NULL)
 					leapsec = optarg;
 				else {
-					(void) fprintf(stderr,
+					fprintf(stderr,
 _("%s: More than one -L option specified\n"),
 						progname);
-					exit(EXIT_FAILURE);
+					return EXIT_FAILURE;
 				}
 				break;
 			case 'v':
-				noise = TRUE;
+				noise = true;
+				break;
+			case 'r':
+				if (timerange_given) {
+				  fprintf(stderr,
+_("%s: More than one -r option specified\n"),
+					  progname);
+				  return EXIT_FAILURE;
+				}
+				if (! timerange_option(optarg)) {
+				  fprintf(stderr,
+_("%s: invalid time range: %s\n"),
+					  progname, optarg);
+				  return EXIT_FAILURE;
+				}
+				timerange_given = true;
+				break;
+			case 'R':
+				if (! redundant_time_option(optarg)) {
+				  fprintf(stderr, _("%s: invalid time: %s\n"),
+					  progname, optarg);
+				  return EXIT_FAILURE;
+				}
 				break;
 			case 's':
-				(void) printf("%s: -s ignored\n", progname);
+				warning(_("-s ignored"));
 				break;
 		}
 	if (optind == argc - 1 && strcmp(argv[optind], "=") == 0)
 		usage(stderr, EXIT_FAILURE);	/* usage message by request */
+	if (hi_time + (hi_time < ZIC_MAX) < redundant_time) {
+	  fprintf(stderr, _("%s: -R time exceeds -r cutoff\n"), progname);
+	  return EXIT_FAILURE;
+	}
+	if (bloat == 0) {
+	  static char const bloat_default[] = ZIC_BLOAT_DEFAULT;
+	  if (strcmp(bloat_default, "slim") == 0)
+	    bloat = -1;
+	  else if (strcmp(bloat_default, "fat") == 0)
+	    bloat = 1;
+	  else
+	    abort(); /* Configuration error.  */
+	}
 	if (directory == NULL)
 		directory = TZDIR;
-	if (yitcommand == NULL)
-		yitcommand = "yearistype";
-
-	setboundaries();
+	if (tzdefault == NULL)
+		tzdefault = TZDEFAULT;
 
 	if (optind < argc && leapsec != NULL) {
 		infile(leapsec);
 		adjleap();
 	}
 
-	for (i = optind; i < argc; ++i)
-		infile(argv[i]);
+	for (k = optind; k < argc; k++)
+		infile(argv[k]);
 	if (errors)
-		exit(EXIT_FAILURE);
+		return EXIT_FAILURE;
 	associate();
+	change_directory(directory);
+	catch_signals();
 	for (i = 0; i < nzones; i = j) {
 		/*
 		** Find the next non-continuation zone entry.
@@ -596,118 +947,332 @@ _("%s: More than one -L option specified\n"),
 	*/
 	for (i = 0; i < nlinks; ++i) {
 		eat(links[i].l_filename, links[i].l_linenum);
-		dolink(links[i].l_from, links[i].l_to);
+		dolink(links[i].l_target, links[i].l_linkname, false);
 		if (noise)
 			for (j = 0; j < nlinks; ++j)
-				if (strcmp(links[i].l_to,
-					links[j].l_from) == 0)
+				if (strcmp(links[i].l_linkname,
+					links[j].l_target) == 0)
 						warning(_("link to link"));
 	}
 	if (lcltime != NULL) {
-		eat("command line", 1);
-		dolink(lcltime, TZDEFAULT);
+		eat(_("command line"), 1);
+		dolink(lcltime, tzdefault, true);
 	}
 	if (psxrules != NULL) {
-		eat("command line", 1);
-		dolink(psxrules, TZDEFRULES);
+		eat(_("command line"), 1);
+		dolink(psxrules, TZDEFRULES, true);
 	}
-	return (errors == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
+	if (warnings && (ferror(stderr) || fclose(stderr) != 0))
+	  return EXIT_FAILURE;
+	return errors ? EXIT_FAILURE : EXIT_SUCCESS;
 }
 
-static void
-dolink(fromfield, tofield)
-const char * const	fromfield;
-const char * const	tofield;
+static bool
+componentcheck(char const *name, char const *component,
+	       char const *component_end)
 {
-	register char *	fromname;
-	register char *	toname;
-
-	if (fromfield[0] == '/')
-		fromname = ecpyalloc(fromfield);
-	else {
-		fromname = ecpyalloc(directory);
-		fromname = ecatalloc(fromname, "/");
-		fromname = ecatalloc(fromname, fromfield);
+	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 (tofield[0] == '/')
-		toname = ecpyalloc(tofield);
-	else {
-		toname = ecpyalloc(directory);
-		toname = ecatalloc(toname, "/");
-		toname = ecatalloc(toname, tofield);
+	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;
 	}
-	/*
-	** We get to be careful here since
-	** there's a fair chance of root running us.
-	*/
-	if (!itsdir(toname))
-		(void) remove(toname);
-	if (link(fromname, toname) != 0) {
-		int	result;
+	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;
+}
 
-		if (mkdirs(toname) != 0)
-			exit(EXIT_FAILURE);
+static bool
+namecheck(const char *name)
+{
+	register char const *cp;
 
-		result = link(fromname, toname);
-#if HAVE_SYMLINK
-		if (result != 0 &&
-			access(fromname, F_OK) == 0 &&
-			!itsdir(fromname)) {
-				const char *s = tofield;
-				register char * symlinkcontents = NULL;
+	/* Benign characters in a portable file name.  */
+	static char const benign[] =
+	  "-/_"
+	  "abcdefghijklmnopqrstuvwxyz"
+	  "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
-				while ((s = strchr(s+1, '/')) != NULL)
-					symlinkcontents =
-						ecatalloc(symlinkcontents,
-						"../");
-				symlinkcontents =
-					ecatalloc(symlinkcontents,
-					fromname);
-				result = symlink(symlinkcontents,
-					toname);
-				if (result == 0)
-warning(_("hard link failed, symbolic link used"));
-				ifree(symlinkcontents);
-		}
-#endif /* HAVE_SYMLINK */
-		if (result != 0) {
-			const char *e = strerror(errno);
+	/* Non-control chars in the POSIX portable character set,
+	   excluding the benign characters.  */
+	static char const printable_and_not_benign[] =
+	  " !\"#$%&'()*+,.0123456789:;<=>?@[\\]^`{|}~";
 
-			(void) fprintf(stderr,
-				_("%s: Can't link from %s to %s: %s\n"),
-				progname, fromname, toname, e);
-			exit(EXIT_FAILURE);
+	register 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;
 		}
 	}
-	ifree(fromname);
-	ifree(toname);
+	return componentcheck(name, component, cp);
+}
+
+/* Generate a randomish name in the same directory as *NAME.  If
+   *NAMEALLOC, put the name into *NAMEALLOC which is assumed to be
+   that returned by a previous call and is thus already almost set up
+   and equal to *NAME; otherwise, allocate a new name and put its
+   address into both *NAMEALLOC and *NAME.  */
+static void
+random_dirent(char const **name, char **namealloc)
+{
+  char const *src = *name;
+  char *dst = *namealloc;
+  static char const prefix[] = ".zic";
+  static char const alphabet[] =
+    "abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "0123456789";
+  enum { prefixlen = sizeof prefix - 1, alphabetlen = sizeof alphabet - 1 };
+  int suffixlen = 6;
+  char const *lastslash = strrchr(src, '/');
+  ptrdiff_t dirlen = lastslash ? lastslash + 1 - src : 0;
+  static unsigned short initialized;
+  int i;
+
+  if (!dst) {
+    dst = emalloc(dirlen + prefixlen + suffixlen + 1);
+    memcpy(dst, src, dirlen);
+    memcpy(dst + dirlen, prefix, prefixlen);
+    dst[dirlen + prefixlen + suffixlen] = '\0';
+    *name = *namealloc = dst;
+  }
+
+  /* This randomization is not the best, but is portable to C89.  */
+  if (!initialized++) {
+    unsigned now = time(NULL);
+    srand(rand() ^ now);
+  }
+  for (i = 0; i < suffixlen; i++)
+    dst[dirlen + prefixlen + i] = alphabet[rand() % alphabetlen];
 }
 
-#define TIME_T_BITS_IN_FILE	64
+/* Prepare to write to the file *OUTNAME, using *TEMPNAME to store the
+   name of the temporary file that will eventually be renamed to
+   *OUTNAME.  Assign the temporary file's name to both *OUTNAME and
+   *TEMPNAME.  If *TEMPNAME is null, allocate the name of any such
+   temporary file; otherwise, reuse *TEMPNAME's storage, which is
+   already set up and only needs its trailing suffix updated.  */
+static FILE *
+open_outfile(char const **outname, char **tempname)
+{
+#if __STDC_VERSION__ < 201112
+  static char const fopen_mode[] = "wb";
+#else
+  static char const fopen_mode[] = "wbx";
+#endif
+
+  FILE *fp;
+  bool dirs_made = false;
+  if (!*tempname)
+    random_dirent(outname, tempname);
+
+  while (! (fp = fopen(*outname, fopen_mode))) {
+    int fopen_errno = errno;
+    if (fopen_errno == ENOENT && !dirs_made) {
+      mkdirs(*outname, true);
+      dirs_made = true;
+    } else if (fopen_errno == EEXIST)
+      random_dirent(outname, tempname);
+    else {
+      fprintf(stderr, _("%s: Can't create %s/%s: %s\n"),
+	      progname, directory, *outname, strerror(fopen_errno));
+      exit(EXIT_FAILURE);
+    }
+  }
+
+  return fp;
+}
 
+/* If TEMPNAME, the result is in the temporary file TEMPNAME even
+   though the user wanted it in NAME, so rename TEMPNAME to NAME.
+   Report an error and exit if there is trouble.  Also, free TEMPNAME.  */
 static void
-setboundaries(void)
+rename_dest(char *tempname, char const *name)
 {
-	register int	i;
+  if (tempname) {
+    if (rename(tempname, name) != 0) {
+      int rename_errno = errno;
+      remove(tempname);
+      fprintf(stderr, _("%s: rename to %s/%s: %s\n"),
+	      progname, directory, name, strerror(rename_errno));
+      exit(EXIT_FAILURE);
+    }
+    free(tempname);
+  }
+}
 
-	min_time = -1;
-	for (i = 0; i < TIME_T_BITS_IN_FILE - 1; ++i)
-		min_time *= 2;
-	max_time = -(min_time + 1);
+/* Create symlink contents suitable for symlinking FROM to TO, as a
+   freshly allocated string.  FROM should be a relative file name, and
+   is relative to the global variable DIRECTORY.  TO can be either
+   relative or absolute.  */
+static char *
+relname(char const *target, char const *linkname)
+{
+  size_t i, taillen, dotdotetcsize;
+  size_t dir_len = 0, dotdots = 0, linksize = SIZE_MAX;
+  char const *f = target;
+  char *result = NULL;
+  if (*linkname == '/') {
+    /* Make F absolute too.  */
+    size_t len = strlen(directory);
+    bool needslash = len && directory[len - 1] != '/';
+    linksize = len + needslash + strlen(target) + 1;
+    f = result = emalloc(linksize);
+    strcpy(result, directory);
+    result[len] = '/';
+    strcpy(result + len + needslash, target);
+  }
+  for (i = 0; f[i] && f[i] == linkname[i]; i++)
+    if (f[i] == '/')
+      dir_len = i + 1;
+  for (; linkname[i]; i++)
+    dotdots += linkname[i] == '/' && linkname[i - 1] != '/';
+  taillen = strlen(f + dir_len);
+  dotdotetcsize = 3 * dotdots + taillen + 1;
+  if (dotdotetcsize <= linksize) {
+    if (!result)
+      result = emalloc(dotdotetcsize);
+    for (i = 0; i < dotdots; i++)
+      memcpy(result + 3 * i, "../", 3);
+    memmove(result + 3 * dotdots, f + dir_len, taillen + 1);
+  }
+  return result;
 }
 
-static int
-itsdir(name)
-const char * const	name;
+static void
+dolink(char const *target, char const *linkname, bool staysymlink)
 {
-	register char *	myname;
-	register int	accres;
+	bool linkdirs_made = false;
+	int link_errno;
+	char *tempname = NULL;
+	char const *outname = linkname;
 
-	myname = ecpyalloc(name);
-	myname = ecatalloc(myname, "/.");
-	accres = access(myname, F_OK);
-	ifree(myname);
-	return accres == 0;
+	check_for_signal();
+
+	if (strcmp(target, "-") == 0) {
+	  if (remove(linkname) == 0 || errno == ENOENT || errno == ENOTDIR)
+	    return;
+	  else {
+	    char const *e = strerror(errno);
+	    fprintf(stderr, _("%s: Can't remove %s/%s: %s\n"),
+		    progname, directory, linkname, e);
+	    exit(EXIT_FAILURE);
+	  }
+	}
+
+	while (true) {
+	  if (linkat(AT_FDCWD, target, AT_FDCWD, outname, AT_SYMLINK_FOLLOW)
+	      == 0) {
+	    link_errno = 0;
+	    break;
+	  }
+	  link_errno = errno;
+	  if (link_errno == EXDEV || link_errno == ENOTSUP)
+	    break;
+
+	  if (link_errno == EEXIST) {
+	    staysymlink &= !tempname;
+	    random_dirent(&outname, &tempname);
+	    if (staysymlink && itssymlink(linkname))
+	      break;
+	  } else if (link_errno == ENOENT && !linkdirs_made) {
+	    mkdirs(linkname, true);
+	    linkdirs_made = true;
+	  } else {
+	    fprintf(stderr, _("%s: Can't link %s/%s to %s/%s: %s\n"),
+		    progname, directory, target, directory, outname,
+		    strerror(link_errno));
+	    exit(EXIT_FAILURE);
+	  }
+	}
+	if (link_errno != 0) {
+	  bool absolute = *target == '/';
+	  char *linkalloc = absolute ? NULL : relname(target, linkname);
+	  char const *contents = absolute ? target : linkalloc;
+	  int symlink_errno;
+
+	  while (true) {
+	    if (symlink(contents, outname) == 0) {
+	      symlink_errno = 0;
+	      break;
+	    }
+	    symlink_errno = errno;
+	    if (symlink_errno == EEXIST)
+	      random_dirent(&outname, &tempname);
+	    else if (symlink_errno == ENOENT && !linkdirs_made) {
+	      mkdirs(linkname, true);
+	      linkdirs_made = true;
+	    } else
+	      break;
+	  }
+	  free(linkalloc);
+	  if (symlink_errno == 0) {
+	    if (link_errno != ENOTSUP && link_errno != EEXIST)
+	      warning(_("symbolic link used because hard link failed: %s"),
+		      strerror(link_errno));
+	  } else {
+	    FILE *fp, *tp;
+	    int c;
+	    fp = fopen(target, "rb");
+	    if (!fp) {
+	      char const *e = strerror(errno);
+	      fprintf(stderr, _("%s: Can't read %s/%s: %s\n"),
+		      progname, directory, target, e);
+	      exit(EXIT_FAILURE);
+	    }
+	    tp = open_outfile(&outname, &tempname);
+	    while ((c = getc(fp)) != EOF)
+	      putc(c, tp);
+	    close_file(tp, directory, linkname, tempname);
+	    close_file(fp, directory, target, NULL);
+	    if (link_errno != ENOTSUP)
+	      warning(_("copy used because hard link failed: %s"),
+		      strerror(link_errno));
+	    else if (symlink_errno != ENOTSUP)
+	      warning(_("copy used because symbolic link failed: %s"),
+		      strerror(symlink_errno));
+	  }
+	}
+	rename_dest(tempname, linkname);
+}
+
+/* Return true if NAME is a symbolic link.  */
+static bool
+itssymlink(char const *name)
+{
+  char c;
+  return 0 <= readlink(name, &c, 1);
 }
 
 /*
@@ -719,12 +1284,10 @@ const char * const	name;
 */
 
 static int
-rcomp(cp1, cp2)
-const void *	cp1;
-const void *	cp2;
+rcomp(const void *cp1, const void *cp2)
 {
-	return strcmp(((const struct rule *) cp1)->r_name,
-		((const struct rule *) cp2)->r_name);
+  struct rule const *r1 = cp1, *r2 = cp2;
+  return strcmp(r1->r_name, r2->r_name);
 }
 
 static void
@@ -732,12 +1295,10 @@ associate(void)
 {
 	register struct zone *	zp;
 	register struct rule *	rp;
-	register int		base, out;
-	register int		i, j;
+	register ptrdiff_t i, j, base, out;
 
 	if (nrules != 0) {
-		(void) qsort((void *) rules, (size_t) nrules,
-			(size_t) sizeof *rules, rcomp);
+		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)
@@ -789,32 +1350,60 @@ associate(void)
 			** 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);
+			zp->z_save = getsave(zp->z_rule, &zp->z_isdst);
 			/*
 			** Note, though, that if there's no rule,
 			** a '%s' in the format is a bad thing.
 			*/
-			if (strchr(zp->z_format, '%') != 0)
-				error(_("%s in ruleless zone"));
+			if (zp->z_format_specifier == 's')
+				error("%s", _("%s in ruleless zone"));
 		}
 	}
 	if (errors)
 		exit(EXIT_FAILURE);
 }
 
+/* Read a text line from FP into BUF, which is of size BUFSIZE.
+   Terminate it with a NUL byte instead of a newline.
+   Return the line's length, not counting the NUL byte.
+   On EOF, return a negative number.
+   On error, report the error and exit.  */
+static ptrdiff_t
+inputline(FILE *fp, char *buf, ptrdiff_t bufsize)
+{
+  ptrdiff_t linelen = 0, ch;
+  while ((ch = getc(fp)) != '\n') {
+    if (ch < 0) {
+      if (ferror(fp)) {
+	error(_("input error"));
+	exit(EXIT_FAILURE);
+      }
+      if (linelen == 0)
+	return -1;
+      error(_("unterminated line"));
+      exit(EXIT_FAILURE);
+    }
+    if (!ch) {
+      error(_("NUL input byte"));
+      exit(EXIT_FAILURE);
+    }
+    buf[linelen++] = ch;
+    if (linelen == bufsize) {
+      error(_("line too long"));
+      exit(EXIT_FAILURE);
+    }
+  }
+  buf[linelen] = '\0';
+  return linelen;
+}
+
 static void
-infile(name)
-const char *	name;
+infile(const char *name)
 {
 	register FILE *			fp;
-	register char **		fields;
-	register char *			cp;
 	register const struct lookup *	lp;
-	register int			nfields;
-	register int			wantcont;
-	register int			num;
-	char				buf[BUFSIZ];
+	register bool			wantcont;
+	register lineno			num;
 
 	if (strcmp(name, "-") == 0) {
 		name = _("standard input");
@@ -822,79 +1411,57 @@ const char *	name;
 	} else if ((fp = fopen(name, "r")) == NULL) {
 		const char *e = strerror(errno);
 
-		(void) fprintf(stderr, _("%s: Can't open %s: %s\n"),
+		fprintf(stderr, _("%s: Can't open %s: %s\n"),
 			progname, name, e);
 		exit(EXIT_FAILURE);
 	}
-	wantcont = FALSE;
+	wantcont = false;
 	for (num = 1; ; ++num) {
+		ptrdiff_t linelen;
+		char buf[_POSIX2_LINE_MAX];
+		int nfields;
+		char *fields[MAX_FIELDS];
 		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;
-		}
+		linelen = inputline(fp, buf, sizeof buf);
+		if (linelen < 0)
+		  break;
+		nfields = getfields(buf, fields,
+				    sizeof fields / sizeof *fields);
 		if (nfields == 0) {
 			/* nothing to do */
 		} else if (wantcont) {
 			wantcont = inzcont(fields, nfields);
 		} else {
+			struct lookup const *line_codes
+			  = name == leapsec ? leap_line_codes : zi_line_codes;
 			lp = byword(fields[0], line_codes);
 			if (lp == NULL)
 				error(_("input line of unknown type"));
-			else switch ((int) (lp->l_value)) {
+			else switch (lp->l_value) {
 				case LC_RULE:
 					inrule(fields, nfields);
-					wantcont = FALSE;
+					wantcont = false;
 					break;
 				case LC_ZONE:
 					wantcont = inzone(fields, nfields);
 					break;
 				case LC_LINK:
 					inlink(fields, nfields);
-					wantcont = FALSE;
+					wantcont = false;
 					break;
 				case LC_LEAP:
-					if (name != leapsec)
-						(void) fprintf(stderr,
-_("%s: Leap line in non leap seconds file %s\n"),
-							progname, name);
-					else	inleap(fields, nfields);
-					wantcont = FALSE;
+					inleap(fields, nfields);
+					wantcont = false;
+					break;
+				case LC_EXPIRES:
+					inexpires(fields, nfields);
+					wantcont = false;
 					break;
-				default:	/* "cannot happen" */
-					(void) fprintf(stderr,
-_("%s: panic: Invalid l_value %d\n"),
-						progname, lp->l_value);
-					exit(EXIT_FAILURE);
+				default: UNREACHABLE();
 			}
 		}
-		ifree((char *) fields);
-	}
-	if (ferror(fp)) {
-		(void) fprintf(stderr, _("%s: Error reading %s\n"),
-			progname, filename);
-		exit(EXIT_FAILURE);
-	}
-	if (fp != stdin && fclose(fp)) {
-		const char *e = strerror(errno);
-
-		(void) fprintf(stderr, _("%s: Error closing %s: %s\n"),
-			progname, filename, e);
-		exit(EXIT_FAILURE);
 	}
+	close_file(fp, NULL, filename, NULL);
 	if (wantcont)
 		error(_("expected continuation line not found"));
 }
@@ -907,194 +1474,214 @@ _("%s: panic: Invalid l_value %d\n"),
 ** Call error with errstring and return zero on errors.
 */
 
-static long
-gethms(string, errstring, signable)
-const char *		string;
-const char * const	errstring;
-const int		signable;
+static zic_t
+gethms(char const *string, char const *errstring)
 {
-	long	hh;
-	int	mm, ss, sign;
+	zic_t	hh;
+	int sign, mm = 0, ss = 0;
+	char hhx, mmx, ssx, xr = '0', xs;
+	int tenths = 0;
+	bool ok = true;
 
 	if (string == NULL || *string == '\0')
 		return 0;
-	if (!signable)
-		sign = 1;
-	else if (*string == '-') {
+	if (*string == '-') {
 		sign = -1;
 		++string;
 	} else	sign = 1;
-	if (sscanf(string, scheck(string, "%ld"), &hh) == 1)
-		mm = ss = 0;
-	else if (sscanf(string, scheck(string, "%ld:%d"), &hh, &mm) == 2)
-		ss = 0;
-	else if (sscanf(string, scheck(string, "%ld:%d:%d"),
-		&hh, &mm, &ss) != 3) {
-			error(errstring);
+	switch (sscanf(string,
+		       "%"SCNdZIC"%c%d%c%d%c%1d%*[0]%c%*[0123456789]%c",
+		       &hh, &hhx, &mm, &mmx, &ss, &ssx, &tenths, &xr, &xs)) {
+	  default: ok = false; break;
+	  case 8:
+	    ok = '0' <= xr && xr <= '9';
+	    /* fallthrough */
+	  case 7:
+	    ok &= ssx == '.';
+	    if (ok && noise)
+	      warning(_("fractional seconds rejected by"
+			" pre-2018 versions of zic"));
+	    /* fallthrough */
+	  case 5: ok &= mmx == ':'; /* fallthrough */
+	  case 3: ok &= hhx == ':'; /* fallthrough */
+	  case 1: break;
+	}
+	if (!ok) {
+			error("%s", errstring);
 			return 0;
 	}
 	if (hh < 0 ||
 		mm < 0 || mm >= MINSPERHOUR ||
 		ss < 0 || ss > SECSPERMIN) {
-			error(errstring);
+			error("%s", errstring);
 			return 0;
 	}
-	if (LONG_MAX / SECSPERHOUR < hh) {
+	if (ZIC_MAX / SECSPERHOUR < hh) {
 		error(_("time overflow"));
 		return 0;
 	}
-	if (noise && hh == HOURSPERDAY && mm == 0 && ss == 0)
-		warning(_("24:00 not handled by pre-1998 versions of zic"));
+	ss += 5 + ((ss ^ 1) & (xr == '0')) <= tenths; /* Round to even.  */
 	if (noise && (hh > HOURSPERDAY ||
 		(hh == HOURSPERDAY && (mm != 0 || ss != 0))))
 warning(_("values over 24 hours not handled by pre-2007 versions of zic"));
-	return oadd(eitol(sign) * hh * eitol(SECSPERHOUR),
-		    eitol(sign) * (eitol(mm) * eitol(SECSPERMIN) + eitol(ss)));
+	return oadd(sign * hh * SECSPERHOUR,
+		    sign * (mm * SECSPERMIN + ss));
+}
+
+static zic_t
+getsave(char *field, bool *isdst)
+{
+  int dst = -1;
+  zic_t save;
+  size_t fieldlen = strlen(field);
+  if (fieldlen != 0) {
+    char *ep = field + fieldlen - 1;
+    switch (*ep) {
+      case 'd': dst = 1; *ep = '\0'; break;
+      case 's': dst = 0; *ep = '\0'; break;
+    }
+  }
+  save = gethms(field, _("invalid saved time"));
+  *isdst = dst < 0 ? save != 0 : dst;
+  return save;
 }
 
 static void
-inrule(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+inrule(char **fields, int nfields)
 {
-	static struct rule	r;
+	struct rule r;
 
 	if (nfields != RULE_FIELDS) {
 		error(_("wrong number of fields on Rule line"));
 		return;
 	}
-	if (*fields[RF_NAME] == '\0') {
-		error(_("nameless rule"));
+	switch (*fields[RF_NAME]) {
+	  case '\0':
+	  case ' ': case '\f': case '\n': case '\r': case '\t': case '\v':
+	  case '+': case '-':
+	  case '0': case '1': case '2': case '3': case '4':
+	  case '5': case '6': case '7': case '8': case '9':
+		error(_("Invalid rule name \"%s\""), fields[RF_NAME]);
 		return;
 	}
 	r.r_filename = filename;
 	r.r_linenum = linenum;
-	r.r_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_save = getsave(fields[RF_SAVE], &r.r_isdst);
+	if (!rulesub(&r, fields[RF_LOYEAR], fields[RF_HIYEAR],
+		     fields[RF_COMMAND], fields[RF_MONTH], fields[RF_DAY],
+		     fields[RF_TOD]))
+	  return;
 	r.r_name = ecpyalloc(fields[RF_NAME]);
 	r.r_abbrvar = ecpyalloc(fields[RF_ABBRVAR]);
 	if (max_abbrvar_len < strlen(r.r_abbrvar))
 		max_abbrvar_len = strlen(r.r_abbrvar);
-	rules = (struct rule *) (void *) erealloc((char *) rules,
-		(int) ((nrules + 1) * sizeof *rules));
+	rules = growalloc(rules, sizeof *rules, nrules, &nrules_alloc);
 	rules[nrules++] = r;
 }
 
-static int
-inzone(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+static bool
+inzone(char **fields, int nfields)
 {
-	register int	i;
-	static char *	buf;
+	register ptrdiff_t i;
 
 	if (nfields < ZONE_MINFIELDS || nfields > ZONE_MAXFIELDS) {
 		error(_("wrong number of fields on Zone line"));
-		return FALSE;
+		return false;
 	}
-	if (strcmp(fields[ZF_NAME], TZDEFAULT) == 0 && lcltime != NULL) {
-		buf = erealloc(buf, (int) (132 + strlen(TZDEFAULT)));
-		(void) sprintf(buf,
+	if (lcltime != NULL && strcmp(fields[ZF_NAME], tzdefault) == 0) {
+		error(
 _("\"Zone %s\" line and -l option are mutually exclusive"),
-			TZDEFAULT);
-		error(buf);
-		return FALSE;
+			tzdefault);
+		return false;
 	}
 	if (strcmp(fields[ZF_NAME], TZDEFRULES) == 0 && psxrules != NULL) {
-		buf = erealloc(buf, (int) (132 + strlen(TZDEFRULES)));
-		(void) sprintf(buf,
+		error(
 _("\"Zone %s\" line and -p option are mutually exclusive"),
 			TZDEFRULES);
-		error(buf);
-		return FALSE;
+		return false;
 	}
 	for (i = 0; i < nzones; ++i)
 		if (zones[i].z_name != NULL &&
 			strcmp(zones[i].z_name, fields[ZF_NAME]) == 0) {
-				buf = erealloc(buf, (int) (132 +
-					strlen(fields[ZF_NAME]) +
-					strlen(zones[i].z_filename)));
-				(void) sprintf(buf,
-_("duplicate zone name %s (file \"%s\", line %d)"),
+				error(_("duplicate zone name %s"
+					" (file \"%s\", line %"PRIdMAX")"),
 					fields[ZF_NAME],
 					zones[i].z_filename,
 					zones[i].z_linenum);
-				error(buf);
-				return FALSE;
+				return false;
 		}
-	return inzsub(fields, nfields, FALSE);
+	return inzsub(fields, nfields, false);
 }
 
-static int
-inzcont(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+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 false;
 	}
-	return inzsub(fields, nfields, TRUE);
+	return inzsub(fields, nfields, true);
 }
 
-static int
-inzsub(fields, nfields, iscont)
-register char ** const	fields;
-const int		nfields;
-const int		iscont;
+static bool
+inzsub(char **fields, int nfields, bool iscont)
 {
 	register char *		cp;
-	static struct zone	z;
-	register int		i_gmtoff, i_rule, i_format;
+	char *			cp1;
+	struct zone z;
+	size_t format_len;
+	register int		i_stdoff, i_rule, i_format;
 	register int		i_untilyear, i_untilmonth;
 	register int		i_untilday, i_untiltime;
-	register int		hasuntil;
+	register bool		hasuntil;
 
 	if (iscont) {
-		i_gmtoff = ZFC_GMTOFF;
+		i_stdoff = ZFC_STDOFF;
 		i_rule = ZFC_RULE;
 		i_format = ZFC_FORMAT;
 		i_untilyear = ZFC_TILYEAR;
 		i_untilmonth = ZFC_TILMONTH;
 		i_untilday = ZFC_TILDAY;
 		i_untiltime = ZFC_TILTIME;
-		z.z_name = NULL;
-	} else {
-		i_gmtoff = ZF_GMTOFF;
+	} else if (!namecheck(fields[ZF_NAME]))
+		return false;
+	else {
+		i_stdoff = ZF_STDOFF;
 		i_rule = ZF_RULE;
 		i_format = ZF_FORMAT;
 		i_untilyear = ZF_TILYEAR;
 		i_untilmonth = ZF_TILMONTH;
 		i_untilday = ZF_TILDAY;
 		i_untiltime = ZF_TILTIME;
-		z.z_name = ecpyalloc(fields[ZF_NAME]);
 	}
 	z.z_filename = filename;
 	z.z_linenum = linenum;
-	z.z_gmtoff = gethms(fields[i_gmtoff], _("invalid UTC offset"), TRUE);
+	z.z_stdoff = gethms(fields[i_stdoff], _("invalid UT offset"));
 	if ((cp = strchr(fields[i_format], '%')) != 0) {
-		if (*++cp != 's' || strchr(cp, '%') != 0) {
+		if ((*++cp != 's' && *cp != 'z') || strchr(cp, '%')
+		    || strchr(fields[i_format], '/')) {
 			error(_("invalid abbreviation format"));
-			return FALSE;
+			return false;
 		}
 	}
-	z.z_rule = ecpyalloc(fields[i_rule]);
-	z.z_format = ecpyalloc(fields[i_format]);
-	if (max_format_len < strlen(z.z_format))
-		max_format_len = strlen(z.z_format);
+	z.z_format_specifier = cp ? *cp : '\0';
+	format_len = strlen(fields[i_format]);
+	if (max_format_len < format_len)
+	  max_format_len = format_len;
 	hasuntil = nfields > i_untilyear;
 	if (hasuntil) {
 		z.z_untilrule.r_filename = filename;
 		z.z_untilrule.r_linenum = linenum;
-		rulesub(&z.z_untilrule,
+		if (!rulesub(
+			&z.z_untilrule,
 			fields[i_untilyear],
 			"only",
 			"",
 			(nfields > i_untilmonth) ?
 			fields[i_untilmonth] : "Jan",
 			(nfields > i_untilday) ? fields[i_untilday] : "1",
-			(nfields > i_untiltime) ? fields[i_untiltime] : "0");
+			(nfields > i_untiltime) ? fields[i_untiltime] : "0"))
+		  return false;
 		z.z_untiltime = rpytime(&z.z_untilrule,
 			z.z_untilrule.r_loyear);
 		if (iscont && nzones > 0 &&
@@ -1106,11 +1693,19 @@ const int		iscont;
 				error(_(
 "Zone continuation line end time is not after end time of previous line"
 					));
-				return FALSE;
+				return false;
 		}
 	}
-	zones = (struct zone *) (void *) erealloc((char *) zones,
-		(int) ((nzones + 1) * sizeof *zones));
+	z.z_name = iscont ? NULL : ecpyalloc(fields[ZF_NAME]);
+	z.z_rule = ecpyalloc(fields[i_rule]);
+	z.z_format = cp1 = ecpyalloc(fields[i_format]);
+	if (z.z_format_specifier == 'z') {
+	  cp1[cp - fields[i_format]] = 's';
+	  if (noise)
+	    warning(_("format '%s' not handled by pre-2015 versions of zic"),
+		    fields[i_format]);
+	}
+	zones = growalloc(zones, sizeof *zones, nzones, &nzones_alloc);
 	zones[nzones++] = z;
 	/*
 	** If there was an UNTIL field on this line,
@@ -1119,36 +1714,34 @@ const int		iscont;
 	return hasuntil;
 }
 
-static void
-inleap(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+static zic_t
+getleapdatetime(char **fields, int nfields, bool expire_line)
 {
 	register const char *		cp;
 	register const struct lookup *	lp;
-	register int			i, j;
-	int				year, month, day;
-	long				dayoff, tod;
+	register zic_t			i, j;
+	zic_t				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, scheck(cp, "%d"), &year) != 1) {
+	if (sscanf(cp, "%"SCNdZIC"%c", &year, &xs) != 1) {
 		/*
 		** Leapin' Lizards!
 		*/
 		error(_("invalid leaping year"));
-		return;
+		return -1;
 	}
-	if (!leapseen || leapmaxyear < year)
+	if (!expire_line) {
+	    if (!leapseen || leapmaxyear < year)
 		leapmaxyear = year;
-	if (!leapseen || leapminyear > year)
+	    if (!leapseen || leapminyear > year)
 		leapminyear = year;
-	leapseen = TRUE;
+	    leapseen = true;
+	}
 	j = EPOCH_YEAR;
 	while (j != year) {
 		if (year > j) {
@@ -1158,75 +1751,81 @@ const int		nfields;
 			--j;
 			i = -len_years[isleap(j)];
 		}
-		dayoff = oadd(dayoff, eitol(i));
+		dayoff = oadd(dayoff, i);
 	}
 	if ((lp = byword(fields[LP_MONTH], mon_names)) == NULL) {
 		error(_("invalid month name"));
-		return;
+		return -1;
 	}
 	month = lp->l_value;
 	j = TM_JANUARY;
 	while (j != month) {
 		i = len_months[isleap(year)][j];
-		dayoff = oadd(dayoff, eitol(i));
+		dayoff = oadd(dayoff, i);
 		++j;
 	}
 	cp = fields[LP_DAY];
-	if (sscanf(cp, scheck(cp, "%d"), &day) != 1 ||
+	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, eitol(day - 1));
-	if (dayoff < 0 && !TYPE_SIGNED(zic_t)) {
-		error(_("time before zero"));
-		return;
+			return -1;
 	}
+	dayoff = oadd(dayoff, day - 1);
 	if (dayoff < min_time / SECSPERDAY) {
 		error(_("time too small"));
-		return;
+		return -1;
 	}
 	if (dayoff > max_time / SECSPERDAY) {
 		error(_("time too large"));
-		return;
+		return -1;
 	}
-	t = (zic_t) dayoff * SECSPERDAY;
-	tod = gethms(fields[LP_TIME], _("invalid time of day"), FALSE);
-	cp = fields[LP_CORR];
-	{
-		register int	positive;
-		int		count;
+	t = dayoff * SECSPERDAY;
+	tod = gethms(fields[LP_TIME], _("invalid time of day"));
+	t = tadd(t, tod);
+	if (t < 0)
+	  error(_("leap second precedes Epoch"));
+	return t;
+}
 
-		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;
-		}
-		leapadd(tadd(t, tod), positive, lp->l_value, count);
-	}
+static void
+inleap(char **fields, int nfields)
+{
+  if (nfields != LEAP_FIELDS)
+    error(_("wrong number of fields on Leap line"));
+  else {
+    zic_t t = getleapdatetime(fields, nfields, false);
+    if (0 <= t) {
+      struct lookup const *lp = byword(fields[LP_ROLL], leap_types);
+      if (!lp)
+	error(_("invalid Rolling/Stationary field on Leap line"));
+      else {
+	int correction = 0;
+	if (!fields[LP_CORR][0]) /* infile() turns "-" into "".  */
+	  correction = -1;
+	else if (strcmp(fields[LP_CORR], "+") == 0)
+	  correction = 1;
+	else
+	  error(_("invalid CORRECTION field on Leap line"));
+	if (correction)
+	  leapadd(t, correction, lp->l_value);
+      }
+    }
+  }
+}
+
+static void
+inexpires(char **fields, int nfields)
+{
+  if (nfields != EXPIRES_FIELDS)
+    error(_("wrong number of fields on Expires line"));
+  else if (0 <= leapexpires)
+    error(_("multiple Expires lines"));
+  else
+    leapexpires = getleapdatetime(fields, nfields, true);
 }
 
 static void
-inlink(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+inlink(char **fields, int nfields)
 {
 	struct link	l;
 
@@ -1234,132 +1833,114 @@ const int		nfields;
 		error(_("wrong number of fields on Link line"));
 		return;
 	}
-	if (*fields[LF_FROM] == '\0') {
-		error(_("blank FROM field on Link line"));
-		return;
-	}
-	if (*fields[LF_TO] == '\0') {
-		error(_("blank TO field on Link line"));
+	if (*fields[LF_TARGET] == '\0') {
+		error(_("blank TARGET field on Link line"));
 		return;
 	}
+	if (! namecheck(fields[LF_LINKNAME]))
+	  return;
 	l.l_filename = filename;
 	l.l_linenum = linenum;
-	l.l_from = ecpyalloc(fields[LF_FROM]);
-	l.l_to = ecpyalloc(fields[LF_TO]);
-	links = (struct link *) (void *) erealloc((char *) links,
-		(int) ((nlinks + 1) * sizeof *links));
+	l.l_target = ecpyalloc(fields[LF_TARGET]);
+	l.l_linkname = ecpyalloc(fields[LF_LINKNAME]);
+	links = growalloc(links, sizeof *links, nlinks, &nlinks_alloc);
 	links[nlinks++] = l;
 }
 
-static void
-rulesub(rp, loyearp, hiyearp, typep, monthp, dayp, timep)
-register 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;
+static bool
+rulesub(struct rule *rp, const char *loyearp, const char *hiyearp,
+	const char *typep, const char *monthp, const char *dayp,
+	const char *timep)
 {
 	register const struct lookup *	lp;
 	register const char *		cp;
 	register char *			dp;
 	register char *			ep;
+	char xs;
 
 	if ((lp = byword(monthp, mon_names)) == NULL) {
 		error(_("invalid month name"));
-		return;
+		return false;
 	}
 	rp->r_month = lp->l_value;
-	rp->r_todisstd = FALSE;
-	rp->r_todisgmt = FALSE;
+	rp->r_todisstd = false;
+	rp->r_todisut = false;
 	dp = ecpyalloc(timep);
 	if (*dp != '\0') {
 		ep = dp + strlen(dp) - 1;
 		switch (lowerit(*ep)) {
 			case 's':	/* Standard */
-				rp->r_todisstd = TRUE;
-				rp->r_todisgmt = FALSE;
+				rp->r_todisstd = true;
+				rp->r_todisut = false;
 				*ep = '\0';
 				break;
 			case 'w':	/* Wall */
-				rp->r_todisstd = FALSE;
-				rp->r_todisgmt = FALSE;
+				rp->r_todisstd = false;
+				rp->r_todisut = false;
 				*ep = '\0';
 				break;
 			case 'g':	/* Greenwich */
 			case 'u':	/* Universal */
 			case 'z':	/* Zulu */
-				rp->r_todisstd = TRUE;
-				rp->r_todisgmt = TRUE;
+				rp->r_todisstd = true;
+				rp->r_todisut = true;
 				*ep = '\0';
 				break;
 		}
 	}
-	rp->r_tod = gethms(dp, _("invalid time of day"), FALSE);
-	ifree(dp);
+	rp->r_tod = gethms(dp, _("invalid time of day"));
+	free(dp);
 	/*
 	** Year work.
 	*/
 	cp = loyearp;
 	lp = byword(cp, begin_years);
 	rp->r_lowasnum = lp == NULL;
-	if (!rp->r_lowasnum) switch ((int) lp->l_value) {
+	if (!rp->r_lowasnum) switch (lp->l_value) {
 		case YR_MINIMUM:
-			rp->r_loyear = INT_MIN;
+			rp->r_loyear = ZIC_MIN;
 			break;
 		case YR_MAXIMUM:
-			rp->r_loyear = INT_MAX;
+			rp->r_loyear = ZIC_MAX;
 			break;
-		default:	/* "cannot happen" */
-			(void) fprintf(stderr,
-				_("%s: panic: Invalid l_value %d\n"),
-				progname, lp->l_value);
-			exit(EXIT_FAILURE);
-	} else if (sscanf(cp, scheck(cp, "%d"), &rp->r_loyear) != 1) {
+		default: UNREACHABLE();
+	} else if (sscanf(cp, "%"SCNdZIC"%c", &rp->r_loyear, &xs) != 1) {
 		error(_("invalid starting year"));
-		return;
+		return false;
 	}
 	cp = hiyearp;
 	lp = byword(cp, end_years);
 	rp->r_hiwasnum = lp == NULL;
-	if (!rp->r_hiwasnum) switch ((int) lp->l_value) {
+	if (!rp->r_hiwasnum) switch (lp->l_value) {
 		case YR_MINIMUM:
-			rp->r_hiyear = INT_MIN;
+			rp->r_hiyear = ZIC_MIN;
 			break;
 		case YR_MAXIMUM:
-			rp->r_hiyear = INT_MAX;
+			rp->r_hiyear = ZIC_MAX;
 			break;
 		case YR_ONLY:
 			rp->r_hiyear = rp->r_loyear;
 			break;
-		default:	/* "cannot happen" */
-			(void) fprintf(stderr,
-				_("%s: panic: Invalid l_value %d\n"),
-				progname, lp->l_value);
-			exit(EXIT_FAILURE);
-	} else if (sscanf(cp, scheck(cp, "%d"), &rp->r_hiyear) != 1) {
+		default: UNREACHABLE();
+	} else if (sscanf(cp, "%"SCNdZIC"%c", &rp->r_hiyear, &xs) != 1) {
 		error(_("invalid ending year"));
-		return;
+		return false;
 	}
 	if (rp->r_loyear > rp->r_hiyear) {
 		error(_("starting year greater than ending year"));
-		return;
+		return false;
 	}
-	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);
+	if (*typep != '\0') {
+		error(_("year type \"%s\" is unsupported; use \"-\" instead"),
+			typep);
+		return false;
 	}
 	/*
 	** Day work.
 	** Accept things such as:
 	**	1
-	**	last-Sunday
+	**	lastSunday
+	**	last-Sunday (undocumented; warn about this)
 	**	Sun<=20
 	**	Sun>=7
 	*/
@@ -1381,142 +1962,196 @@ const char * const		timep;
 			*ep++ = 0;
 			if (*ep++ != '=') {
 				error(_("invalid day of month"));
-				ifree(dp);
-				return;
+				free(dp);
+				return false;
 			}
 			if ((lp = byword(dp, wday_names)) == NULL) {
 				error(_("invalid weekday name"));
-				ifree(dp);
-				return;
+				free(dp);
+				return false;
 			}
 			rp->r_wday = lp->l_value;
 		}
-		if (sscanf(ep, scheck(ep, "%d"), &rp->r_dayofmonth) != 1 ||
+		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"));
-				ifree(dp);
-				return;
+				free(dp);
+				return false;
 		}
 	}
-	ifree(dp);
+	free(dp);
+	return true;
 }
 
 static void
-convert(val, buf)
-const long	val;
-char * const	buf;
+convert(uint_fast32_t val, char *buf)
 {
 	register int	i;
 	register int	shift;
+	unsigned char *const b = (unsigned char *) buf;
 
 	for (i = 0, shift = 24; i < 4; ++i, shift -= 8)
-		buf[i] = val >> shift;
+	  b[i] = (val >> shift) & 0xff;
 }
 
 static void
-convert64(val, buf)
-const zic_t	val;
-char * const	buf;
+convert64(uint_fast64_t val, char *buf)
 {
 	register int	i;
 	register int	shift;
+	unsigned char *const b = (unsigned char *) buf;
 
 	for (i = 0, shift = 56; i < 8; ++i, shift -= 8)
-		buf[i] = val >> shift;
+	  b[i] = (val >> shift) & 0xff;
 }
 
 static void
-puttzcode(val, fp)
-const long	val;
-FILE * const	fp;
+puttzcode(const int_fast32_t val, FILE *const fp)
 {
 	char	buf[4];
 
 	convert(val, buf);
-	(void) fwrite((void *) buf, (size_t) sizeof buf, (size_t) 1, fp);
+	fwrite(buf, sizeof buf, 1, fp);
 }
 
 static void
-puttzcode64(val, fp)
-const zic_t	val;
-FILE * const	fp;
+puttzcodepass(zic_t val, FILE *fp, int pass)
 {
+  if (pass == 1)
+    puttzcode(val, fp);
+  else {
 	char	buf[8];
 
 	convert64(val, buf);
-	(void) fwrite((void *) buf, (size_t) sizeof buf, (size_t) 1, fp);
+	fwrite(buf, sizeof buf, 1, fp);
+  }
 }
 
 static int
-atcomp(avp, bvp)
-const void *	avp;
-const void *	bvp;
+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);
+  struct attype const *ap = avp, *bp = bvp;
+  zic_t a = ap->at, b = bp->at;
+  return a < b ? -1 : a > b;
 }
 
-static int
-is32(x)
-const zic_t	x;
+struct timerange {
+  int defaulttype;
+  ptrdiff_t base, count;
+  int leapbase, leapcount;
+  bool leapexpiry;
+};
+
+static struct timerange
+limitrange(struct timerange r, zic_t lo, zic_t hi,
+	   zic_t const *ats, unsigned char const *types)
 {
-	return INT32_MIN <= x && x <= INT32_MAX;
+  /* Omit ordinary transitions < LO.  */
+  while (0 < r.count && ats[r.base] < lo) {
+    r.defaulttype = types[r.base];
+    r.count--;
+    r.base++;
+  }
+
+  /* Omit as many initial leap seconds as possible, such that the
+     first leap second in the truncated list is <= LO, and is a
+     positive leap second if and only if it has a positive correction.
+     This supports common TZif readers that assume that the first leap
+     second is positive if and only if its correction is positive.  */
+  while (1 < r.leapcount && trans[r.leapbase + 1] <= lo) {
+    r.leapcount--;
+    r.leapbase++;
+  }
+  while (0 < r.leapbase
+	 && ((corr[r.leapbase - 1] < corr[r.leapbase])
+	     != (0 < corr[r.leapbase]))) {
+    r.leapcount++;
+    r.leapbase--;
+  }
+
+
+  /* Omit ordinary and leap second transitions greater than HI + 1.  */
+  if (hi < max_time) {
+    while (0 < r.count && hi + 1 < ats[r.base + r.count - 1])
+      r.count--;
+    while (0 < r.leapcount && hi + 1 < trans[r.leapbase + r.leapcount - 1])
+      r.leapcount--;
+  }
+
+  /* Determine whether to append an expiration to the leap second table.  */
+  r.leapexpiry = 0 <= leapexpires && leapexpires - 1 <= hi;
+
+  return r;
 }
 
 static void
-writezone(name, string)
-const char * const	name;
-const char * const	string;
+writezone(const char *const name, const char *const string, char version,
+	  int defaulttype)
 {
 	register FILE *			fp;
-	register int			i, j;
-	register int			leapcnt32, leapi32;
-	register int			timecnt32, timei32;
+	register ptrdiff_t		i, j;
 	register int			pass;
-	static char *			fullname;
-	static const struct tzhead	tzh0;
-	static struct tzhead		tzh;
-	zic_t				ats[TZ_MAX_TIMES];
-	unsigned char			types[TZ_MAX_TIMES];
+	zic_t one = 1;
+	zic_t y2038_boundary = one << 31;
+	ptrdiff_t nats = timecnt + WORK_AROUND_QTBUG_53071;
+	char *tempname = NULL;
+	char const *outname = name;
+
+	/* Allocate the ATS and TYPES arrays via a single malloc,
+	   as this is a bit faster.  */
+	zic_t *ats = emalloc(align_to(size_product(nats, sizeof *ats + 1),
+				      _Alignof(zic_t)));
+	void *typesptr = ats + nats;
+	unsigned char *types = typesptr;
+	struct timerange rangeall = {0}, range32, range64;
 
 	/*
 	** Sort.
 	*/
 	if (timecnt > 1)
-		(void) qsort((void *) attypes, (size_t) timecnt,
-			(size_t) sizeof *attypes, atcomp);
+		qsort(attypes, timecnt, sizeof *attypes, atcomp);
 	/*
 	** Optimize.
 	*/
 	{
-		int	fromi;
-		int	toi;
+		ptrdiff_t fromi, toi;
 
 		toi = 0;
 		fromi = 0;
-		while (fromi < timecnt && attypes[fromi].at < min_time)
-			++fromi;
-		if (isdsts[0] == 0)
-			while (fromi < timecnt && attypes[fromi].type == 0)
-				++fromi;	/* handled by default rule */
 		for ( ; fromi < timecnt; ++fromi) {
-			if (toi != 0 && ((attypes[fromi].at +
-				gmtoffs[attypes[toi - 1].type]) <=
-				(attypes[toi - 1].at + gmtoffs[toi == 1 ? 0
-				: attypes[toi - 2].type]))) {
+			if (toi != 0
+			    && ((attypes[fromi].at
+				 + utoffs[attypes[toi - 1].type])
+				<= (attypes[toi - 1].at
+				    + utoffs[toi == 1 ? 0
+					     : attypes[toi - 2].type]))) {
 					attypes[toi - 1].type =
 						attypes[fromi].type;
 					continue;
 			}
-			if (toi == 0 ||
-				attypes[toi - 1].type != attypes[fromi].type)
+			if (toi == 0
+			    || attypes[fromi].dontmerge
+			    || (utoffs[attypes[toi - 1].type]
+				!= utoffs[attypes[fromi].type])
+			    || (isdsts[attypes[toi - 1].type]
+				!= isdsts[attypes[fromi].type])
+			    || (desigidx[attypes[toi - 1].type]
+				!= desigidx[attypes[fromi].type]))
 					attypes[toi++] = attypes[fromi];
 		}
 		timecnt = toi;
 	}
+
+	if (noise && timecnt > 1200) {
+	  if (timecnt > TZ_MAX_TIMES)
+		warning(_("reference clients mishandle"
+			  " more than %d transition times"),
+			TZ_MAX_TIMES);
+	  else
+		warning(_("pre-2014 clients may mishandle"
+			  " more than 1200 transition times"));
+	}
 	/*
 	** Transfer.
 	*/
@@ -1524,6 +2159,7 @@ const char * const	string;
 		ats[i] = attypes[i].at;
 		types[i] = attypes[i].type;
 	}
+
 	/*
 	** Correct for leap seconds.
 	*/
@@ -1535,92 +2171,142 @@ const char * const	string;
 				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;
-	}
-	while (leapcnt32 > 0 && !is32(trans[leapcnt32 - 1]))
-		--leapcnt32;
-	while (leapcnt32 > 0 && !is32(trans[leapi32])) {
-		--leapcnt32;
-		++leapi32;
-	}
-	fullname = erealloc(fullname,
-		(int) (strlen(directory) + 1 + strlen(name) + 1));
-	(void) sprintf(fullname, "%s/%s", directory, name);
-	/*
-	** Remove old file, if any, to snap links.
-	*/
-	if (!itsdir(fullname) && 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);
+	/* Work around QTBUG-53071 for timestamps less than y2038_boundary - 1,
+	   by inserting a no-op transition at time y2038_boundary - 1.
+	   This works only for timestamps before the boundary, which
+	   should be good enough in practice as QTBUG-53071 should be
+	   long-dead by 2038.  Do this after correcting for leap
+	   seconds, as the idea is to insert a transition just before
+	   32-bit time_t rolls around, and this occurs at a slightly
+	   different moment if transitions are leap-second corrected.  */
+	if (WORK_AROUND_QTBUG_53071 && timecnt != 0 && want_bloat()
+	    && ats[timecnt - 1] < y2038_boundary - 1 && strchr(string, '<')) {
+	  ats[timecnt] = y2038_boundary - 1;
+	  types[timecnt] = types[timecnt - 1];
+	  timecnt++;
 	}
-	if ((fp = fopen(fullname, "wb")) == NULL) {
-		if (mkdirs(fullname) != 0)
-			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);
-		}
+	rangeall.defaulttype = defaulttype;
+	rangeall.count = timecnt;
+	rangeall.leapcount = leapcnt;
+	range64 = limitrange(rangeall, lo_time,
+			     max(hi_time,
+				 redundant_time - (ZIC_MIN < redundant_time)),
+			     ats, types);
+	range32 = limitrange(range64, INT32_MIN, INT32_MAX, ats, types);
+
+	/* TZif version 4 is needed if a no-op transition is appended to
+	   indicate the expiration of the leap second table, or if the first
+	   leap second transition is not to a +1 or -1 correction.  */
+	for (pass = 1; pass <= 2; pass++) {
+	  struct timerange const *r = pass == 1 ? &range32 : &range64;
+	  if (pass == 1 && !want_bloat())
+	    continue;
+	  if (r->leapexpiry) {
+	    if (noise)
+	      warning(_("%s: pre-2021b clients may mishandle"
+			" leap second expiry"),
+		      name);
+	    version = '4';
+	  }
+	  if (0 < r->leapcount
+	      && corr[r->leapbase] != 1 && corr[r->leapbase] != -1) {
+	    if (noise)
+	      warning(_("%s: pre-2021b clients may mishandle"
+			" leap second table truncation"),
+		      name);
+	    version = '4';
+	  }
+	  if (version == '4')
+	    break;
 	}
+
+	fp = open_outfile(&outname, &tempname);
+
 	for (pass = 1; pass <= 2; ++pass) {
-		register int	thistimei, thistimecnt;
-		register int	thisleapi, thisleapcnt;
-		register int	thistimelim, thisleaplim;
-		int		writetype[TZ_MAX_TIMES];
+		register ptrdiff_t thistimei, thistimecnt, thistimelim;
+		register int	thisleapi, thisleapcnt, thisleaplim;
+		struct tzhead tzh;
+		int pretranstype = -1, thisdefaulttype;
+		bool locut, hicut, thisleapexpiry;
+		zic_t lo, thismin, thismax;
+		int old0;
+		char		omittype[TZ_MAX_TYPES];
 		int		typemap[TZ_MAX_TYPES];
-		register int	thistypecnt;
+		int		thistypecnt, stdcnt, utcnt;
 		char		thischars[TZ_MAX_CHARS];
-		char		thischarcnt;
-		int 		indmap[TZ_MAX_CHARS];
+		int		thischarcnt;
+		bool		toomanytimes;
+		int		indmap[TZ_MAX_CHARS];
 
 		if (pass == 1) {
-			thistimei = timei32;
-			thistimecnt = timecnt32;
-			thisleapi = leapi32;
-			thisleapcnt = leapcnt32;
+			thisdefaulttype = range32.defaulttype;
+			thistimei = range32.base;
+			thistimecnt = range32.count;
+			toomanytimes = thistimecnt >> 31 >> 1 != 0;
+			thisleapi = range32.leapbase;
+			thisleapcnt = range32.leapcount;
+			thisleapexpiry = range32.leapexpiry;
+			thismin = INT32_MIN;
+			thismax = INT32_MAX;
 		} else {
-			thistimei = 0;
-			thistimecnt = timecnt;
-			thisleapi = 0;
-			thisleapcnt = leapcnt;
+			thisdefaulttype = range64.defaulttype;
+			thistimei = range64.base;
+			thistimecnt = range64.count;
+			toomanytimes = thistimecnt >> 31 >> 31 >> 2 != 0;
+			thisleapi = range64.leapbase;
+			thisleapcnt = range64.leapcount;
+			thisleapexpiry = range64.leapexpiry;
+			thismin = min_time;
+			thismax = max_time;
 		}
+		if (toomanytimes)
+		  error(_("too many transition times"));
+
+		locut = thismin < lo_time && lo_time <= thismax;
+		hicut = thismin <= hi_time && hi_time < thismax;
 		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;
+		memset(omittype, true, typecnt);
+
+		/* Determine whether to output a transition before the first
+		   transition in range.  This is needed when the output is
+		   truncated at the start, and is also useful when catering to
+		   buggy 32-bit clients that do not use time type 0 for
+		   timestamps before the first transition.  */
+		if ((locut || (pass == 1 && thistimei))
+		    && ! (thistimecnt && ats[thistimei] == lo_time)) {
+		  pretranstype = thisdefaulttype;
+		  omittype[pretranstype] = false;
 		}
+
+		/* Arguably the default time type in the 32-bit data
+		   should be range32.defaulttype, which is suited for
+		   timestamps just before INT32_MIN.  However, zic
+		   traditionally used the time type of the indefinite
+		   past instead.  Internet RFC 8532 says readers should
+		   ignore 32-bit data, so this discrepancy matters only
+		   to obsolete readers where the traditional type might
+		   be more appropriate even if it's "wrong".  So, use
+		   the historical zic value, unless -r specifies a low
+		   cutoff that excludes some 32-bit timestamps.  */
+		if (pass == 1 && lo_time <= thismin)
+		  thisdefaulttype = range64.defaulttype;
+
+		if (locut)
+		  thisdefaulttype = unspecifiedtype;
+		omittype[thisdefaulttype] = false;
+		for (i = thistimei; i < thistimelim; i++)
+		  omittype[types[i]] = false;
+		if (hicut)
+		  omittype[unspecifiedtype] = false;
+
+		/* Reorder types to make THISDEFAULTTYPE type 0.
+		   Use TYPEMAP to swap OLD0 and THISDEFAULTTYPE so that
+		   THISDEFAULTTYPE appears as type 0 in the output instead
+		   of OLD0.  TYPEMAP also omits unused types.  */
+		old0 = strlen(omittype);
+
 #ifndef LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH
 		/*
 		** For some pre-2011 systems: if the last-to-be-written
@@ -1630,111 +2316,153 @@ const char * const	string;
 		** (to help get global "altzone" and "timezone" variables
 		** set correctly).
 		*/
-		{
+		if (want_bloat()) {
 			register int	mrudst, mrustd, hidst, histd, type;
 
 			hidst = histd = mrudst = mrustd = -1;
-			for (i = thistimei; i < thistimelim; ++i)
+			if (0 <= pretranstype) {
+			  if (isdsts[pretranstype])
+			    mrudst = pretranstype;
+			  else
+			    mrustd = pretranstype;
+			}
+			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;
+			for (i = old0; i < typecnt; i++) {
+			  int h = (i == old0 ? thisdefaulttype
+				   : i == thisdefaulttype ? old0 : i);
+			  if (!omittype[h]) {
+			    if (isdsts[h])
+			      hidst = i;
+			    else
+			      histd = i;
+			  }
+			}
 			if (hidst >= 0 && mrudst >= 0 && hidst != mrudst &&
-				gmtoffs[hidst] != gmtoffs[mrudst]) {
+				utoffs[hidst] != utoffs[mrudst]) {
 					isdsts[mrudst] = -1;
-					type = addtype(gmtoffs[mrudst],
-						&chars[abbrinds[mrudst]],
-						TRUE,
+					type = addtype(utoffs[mrudst],
+						&chars[desigidx[mrudst]],
+						true,
 						ttisstds[mrudst],
-						ttisgmts[mrudst]);
-					isdsts[mrudst] = TRUE;
-					writetype[type] = TRUE;
+						ttisuts[mrudst]);
+					isdsts[mrudst] = 1;
+					omittype[type] = false;
 			}
 			if (histd >= 0 && mrustd >= 0 && histd != mrustd &&
-				gmtoffs[histd] != gmtoffs[mrustd]) {
+				utoffs[histd] != utoffs[mrustd]) {
 					isdsts[mrustd] = -1;
-					type = addtype(gmtoffs[mrustd],
-						&chars[abbrinds[mrustd]],
-						FALSE,
+					type = addtype(utoffs[mrustd],
+						&chars[desigidx[mrustd]],
+						false,
 						ttisstds[mrustd],
-						ttisgmts[mrustd]);
-					isdsts[mrustd] = FALSE;
-					writetype[type] = TRUE;
+						ttisuts[mrustd]);
+					isdsts[mrustd] = 0;
+					omittype[type] = false;
 			}
 		}
 #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 = old0; i < typecnt; i++)
+		  if (!omittype[i])
+		    typemap[i == old0 ? thisdefaulttype
+			    : i == thisdefaulttype ? old0 : i]
+		      = thistypecnt++;
+
 		for (i = 0; i < sizeof indmap / sizeof indmap[0]; ++i)
 			indmap[i] = -1;
-		thischarcnt = 0;
-		for (i = 0; i < typecnt; ++i) {
+		thischarcnt = stdcnt = utcnt = 0;
+		for (i = old0; i < typecnt; i++) {
 			register char *	thisabbr;
 
-			if (!writetype[i])
+			if (omittype[i])
 				continue;
-			if (indmap[abbrinds[i]] >= 0)
+			if (ttisstds[i])
+			  stdcnt = thistypecnt;
+			if (ttisuts[i])
+			  utcnt = thistypecnt;
+			if (indmap[desigidx[i]] >= 0)
 				continue;
-			thisabbr = &chars[abbrinds[i]];
+			thisabbr = &chars[desigidx[i]];
 			for (j = 0; j < thischarcnt; ++j)
 				if (strcmp(&thischars[j], thisabbr) == 0)
 					break;
 			if (j == thischarcnt) {
-				(void) strcpy(&thischars[(int) thischarcnt],
-					thisabbr);
+				strcpy(&thischars[thischarcnt], thisabbr);
 				thischarcnt += strlen(thisabbr) + 1;
 			}
-			indmap[abbrinds[i]] = j;
+			indmap[desigidx[i]] = j;
 		}
-#define DO(field)	(void) fwrite((void *) tzh.field, \
-				(size_t) sizeof tzh.field, (size_t) 1, fp)
-		tzh = tzh0;
-		(void) strncpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
-		tzh.tzh_version[0] = ZIC_VERSION;
-		convert(eitol(thistypecnt), tzh.tzh_ttisgmtcnt);
-		convert(eitol(thistypecnt), tzh.tzh_ttisstdcnt);
-		convert(eitol(thisleapcnt), tzh.tzh_leapcnt);
-		convert(eitol(thistimecnt), tzh.tzh_timecnt);
-		convert(eitol(thistypecnt), tzh.tzh_typecnt);
-		convert(eitol(thischarcnt), tzh.tzh_charcnt);
+		if (pass == 1 && !want_bloat()) {
+		  hicut = thisleapexpiry = false;
+		  pretranstype = -1;
+		  thistimecnt = thisleapcnt = 0;
+		  thistypecnt = thischarcnt = 1;
+		}
+#define DO(field)	fwrite(tzh.field, sizeof tzh.field, 1, fp)
+		memset(&tzh, 0, sizeof tzh);
+		memcpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
+		tzh.tzh_version[0] = version;
+		convert(utcnt, tzh.tzh_ttisutcnt);
+		convert(stdcnt, tzh.tzh_ttisstdcnt);
+		convert(thisleapcnt + thisleapexpiry, tzh.tzh_leapcnt);
+		convert((0 <= pretranstype) + thistimecnt + hicut,
+			tzh.tzh_timecnt);
+		convert(thistypecnt, tzh.tzh_typecnt);
+		convert(thischarcnt, tzh.tzh_charcnt);
 		DO(tzh_magic);
 		DO(tzh_version);
 		DO(tzh_reserved);
-		DO(tzh_ttisgmtcnt);
+		DO(tzh_ttisutcnt);
 		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)
-				puttzcode((long) ats[i], fp);
-			else	puttzcode64(ats[i], fp);
+		if (pass == 1 && !want_bloat()) {
+		  /* Output a minimal data block with just one time type.  */
+		  puttzcode(0, fp);	/* utoff */
+		  putc(0, fp);		/* dst */
+		  putc(0, fp);		/* index of abbreviation */
+		  putc(0, fp);		/* empty-string abbreviation */
+		  continue;
+		}
+
+		/* Output a LO_TIME transition if needed; see limitrange.
+		   But do not go below the minimum representable value
+		   for this pass.  */
+		lo = pass == 1 && lo_time < INT32_MIN ? INT32_MIN : lo_time;
+
+		if (0 <= pretranstype)
+		  puttzcodepass(lo, fp, pass);
 		for (i = thistimei; i < thistimelim; ++i) {
-			unsigned char	uc;
+		  puttzcodepass(ats[i], fp, pass);
+		}
+		if (hicut)
+		  puttzcodepass(hi_time + 1, fp, pass);
+		if (0 <= pretranstype)
+		  putc(typemap[pretranstype], fp);
+		for (i = thistimei; i < thistimelim; i++)
+		  putc(typemap[types[i]], fp);
+		if (hicut)
+		  putc(typemap[unspecifiedtype], fp);
 
-			uc = typemap[types[i]];
-			(void) fwrite((void *) &uc,
-				(size_t) sizeof uc,
-				(size_t) 1,
-				fp);
+		for (i = old0; i < typecnt; i++) {
+		  int h = (i == old0 ? thisdefaulttype
+			   : i == thisdefaulttype ? old0 : i);
+		  if (!omittype[h]) {
+		    puttzcode(utoffs[h], fp);
+		    putc(isdsts[h], fp);
+		    putc(indmap[desigidx[h]], fp);
+		  }
 		}
-		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((void *) thischars,
-				(size_t) sizeof thischars[0],
-				(size_t) thischarcnt, fp);
+			fwrite(thischars, sizeof thischars[0],
+				      thischarcnt, fp);
+		thisleaplim = thisleapi + thisleapcnt;
 		for (i = thisleapi; i < thisleaplim; ++i) {
 			register zic_t	todo;
 
@@ -1753,72 +2481,114 @@ const char * const	string;
 							++j;
 					j = types[j - 1];
 				}
-				todo = tadd(trans[i], -gmtoffs[j]);
+				todo = tadd(trans[i], -utoffs[j]);
 			} else	todo = trans[i];
-			if (pass == 1)
-				puttzcode((long) todo, fp);
-			else	puttzcode64(todo, fp);
+			puttzcodepass(todo, fp, pass);
 			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);
-	if (ferror(fp) || fclose(fp)) {
-		(void) fprintf(stderr, _("%s: Error writing %s\n"),
-			progname, fullname);
-		exit(EXIT_FAILURE);
+		if (thisleapexpiry) {
+		  /* Append a no-op leap correction indicating when the leap
+		     second table expires.  Although this does not conform to
+		     Internet RFC 8536, most clients seem to accept this and
+		     the plan is to amend the RFC to allow this in version 4
+		     TZif files.  */
+		  puttzcodepass(leapexpires, fp, pass);
+		  puttzcode(thisleaplim ? corr[thisleaplim - 1] : 0, fp);
+		}
+		if (stdcnt != 0)
+		  for (i = old0; i < typecnt; i++)
+			if (!omittype[i])
+				putc(ttisstds[i], fp);
+		if (utcnt != 0)
+		  for (i = old0; i < typecnt; i++)
+			if (!omittype[i])
+				putc(ttisuts[i], fp);
 	}
+	fprintf(fp, "\n%s\n", string);
+	close_file(fp, directory, name, tempname);
+	rename_dest(tempname, name);
+	free(ats);
 }
 
-static void
-doabbr(abbr, format, letters, isdst, doquotes)
-char * const		abbr;
-const char * const	format;
-const char * const	letters;
-const int		isdst;
-const int		doquotes;
+static char const *
+abbroffset(char *buf, zic_t offset)
+{
+  char sign = '+';
+  int seconds, minutes;
+
+  if (offset < 0) {
+    offset = -offset;
+    sign = '-';
+  }
+
+  seconds = offset % SECSPERMIN;
+  offset /= SECSPERMIN;
+  minutes = offset % MINSPERHOUR;
+  offset /= MINSPERHOUR;
+  if (100 <= offset) {
+    error(_("%%z UT offset magnitude exceeds 99:59:59"));
+    return "%z";
+  } else {
+    char *p = buf;
+    *p++ = sign;
+    *p++ = '0' + offset / 10;
+    *p++ = '0' + offset % 10;
+    if (minutes | seconds) {
+      *p++ = '0' + minutes / 10;
+      *p++ = '0' + minutes % 10;
+      if (seconds) {
+	*p++ = '0' + seconds / 10;
+	*p++ = '0' + seconds % 10;
+      }
+    }
+    *p = '\0';
+    return buf;
+  }
+}
+
+static char const disable_percent_s[] = "";
+
+static size_t
+doabbr(char *abbr, struct zone const *zp, char const *letters,
+       bool isdst, zic_t save, bool doquotes)
 {
 	register char *	cp;
 	register char *	slashp;
-	register int	len;
+	register size_t	len;
+	char const *format = zp->z_format;
 
 	slashp = strchr(format, '/');
 	if (slashp == NULL) {
-		if (letters == NULL)
-			(void) strcpy(abbr, format);
-		else	(void) sprintf(abbr, format, letters);
+	  char letterbuf[PERCENT_Z_LEN_BOUND + 1];
+	  if (zp->z_format_specifier == 'z')
+	    letters = abbroffset(letterbuf, zp->z_stdoff + save);
+	  else if (!letters)
+	    letters = "%s";
+	  else if (letters == disable_percent_s)
+	    return 0;
+	  sprintf(abbr, format, letters);
 	} else if (isdst) {
-		(void) strcpy(abbr, slashp + 1);
+		strcpy(abbr, slashp + 1);
 	} else {
-		if (slashp > format)
-			(void) strncpy(abbr, format,
-				(unsigned) (slashp - format));
+		memcpy(abbr, format, slashp - format);
 		abbr[slashp - format] = '\0';
 	}
-	if (!doquotes)
-		return;
-	for (cp = abbr; *cp != '\0'; ++cp)
-		if (strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ", *cp) == NULL &&
-			strchr("abcdefghijklmnopqrstuvwxyz", *cp) == NULL)
-				break;
 	len = strlen(abbr);
+	if (!doquotes)
+		return len;
+	for (cp = abbr; is_alpha(*cp); cp++)
+		continue;
 	if (len > 0 && *cp == '\0')
-		return;
+		return len;
 	abbr[len + 2] = '\0';
 	abbr[len + 1] = '>';
-	for ( ; len > 0; --len)
-		abbr[len] = abbr[len - 1];
+	memmove(abbr + 1, abbr, len);
 	abbr[0] = '<';
+	return len + 2;
 }
 
 static void
-updateminmax(x)
-const int	x;
+updateminmax(const zic_t x)
 {
 	if (min_year > x)
 		min_year = x;
@@ -1827,47 +2597,42 @@ const int	x;
 }
 
 static int
-stringoffset(result, offset)
-char *	result;
-long	offset;
+stringoffset(char *result, zic_t offset)
 {
 	register int	hours;
 	register int	minutes;
 	register int	seconds;
+	bool negative = offset < 0;
+	int len = negative;
 
-	result[0] = '\0';
-	if (offset < 0) {
-		(void) strcpy(result, "-");
+	if (negative) {
 		offset = -offset;
+		result[0] = '-';
 	}
 	seconds = offset % SECSPERMIN;
 	offset /= SECSPERMIN;
 	minutes = offset % MINSPERHOUR;
 	offset /= MINSPERHOUR;
 	hours = offset;
-	if (hours >= HOURSPERDAY) {
+	if (hours >= HOURSPERDAY * DAYSPERWEEK) {
 		result[0] = '\0';
-		return -1;
+		return 0;
 	}
-	(void) sprintf(end(result), "%d", hours);
+	len += sprintf(result + len, "%d", hours);
 	if (minutes != 0 || seconds != 0) {
-		(void) sprintf(end(result), ":%02d", minutes);
+		len += sprintf(result + len, ":%02d", minutes);
 		if (seconds != 0)
-			(void) sprintf(end(result), ":%02d", seconds);
+			len += sprintf(result + len, ":%02d", seconds);
 	}
-	return 0;
+	return len;
 }
 
 static int
-stringrule(result, rp, dstoff, gmtoff)
-char *				result;
-const struct rule * const	rp;
-const long			dstoff;
-const long			gmtoff;
+stringrule(char *result, struct rule *const rp, zic_t save, zic_t stdoff)
 {
-	register long	tod;
+	register zic_t	tod = rp->r_tod;
+	register int	compat = 0;
 
-	result = end(result);
 	if (rp->r_dycode == DC_DOM) {
 		register int	month, total;
 
@@ -1876,149 +2641,219 @@ const long			gmtoff;
 		total = 0;
 		for (month = 0; month < rp->r_month; ++month)
 			total += len_months[0][month];
-		(void) sprintf(result, "J%d", total + rp->r_dayofmonth);
+		/* 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 {
 		register int	week;
+		register int	wday = rp->r_wday;
+		register int	wdayoff;
 
 		if (rp->r_dycode == DC_DOWGEQ) {
-			if ((rp->r_dayofmonth % DAYSPERWEEK) != 1)
-				return -1;
-			week = 1 + rp->r_dayofmonth / DAYSPERWEEK;
+			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 {
-				if ((rp->r_dayofmonth % DAYSPERWEEK) != 0)
-					return -1;
+				wdayoff = rp->r_dayofmonth % DAYSPERWEEK;
+				if (wdayoff)
+					compat = 2013;
+				wday -= wdayoff;
+				tod += wdayoff * SECSPERDAY;
 				week = rp->r_dayofmonth / DAYSPERWEEK;
 			}
 		} else	return -1;	/* "cannot happen" */
-		(void) sprintf(result, "M%d.%d.%d",
-			rp->r_month + 1, week, rp->r_wday);
-	}
-	tod = rp->r_tod;
-	if (rp->r_todisgmt)
-		tod += gmtoff;
-	if (rp->r_todisstd && rp->r_stdoff == 0)
-		tod += dstoff;
-	if (tod < 0) {
-		result[0] = '\0';
-		return -1;
+		if (wday < 0)
+			wday += DAYSPERWEEK;
+		result += sprintf(result, "M%d.%d.%d",
+				  rp->r_month + 1, week, wday);
 	}
+	if (rp->r_todisut)
+	  tod += stdoff;
+	if (rp->r_todisstd && !rp->r_isdst)
+	  tod += save;
 	if (tod != 2 * SECSPERMIN * MINSPERHOUR) {
-		(void) strcat(result, "/");
-		if (stringoffset(end(result), tod) != 0)
+		*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 0;
+	return compat;
 }
 
-static void
-stringzone(result, zpfirst, zonecount)
-char *				result;
-const struct zone * const	zpfirst;
-const int			zonecount;
+static int
+rule_cmp(struct rule const *a, struct rule const *b)
+{
+	if (!a)
+		return -!!b;
+	if (!b)
+		return 1;
+	if (a->r_hiyear != b->r_hiyear)
+		return a->r_hiyear < b->r_hiyear ? -1 : 1;
+	if (a->r_hiyear == ZIC_MAX)
+		return 0;
+	if (a->r_month - b->r_month != 0)
+		return a->r_month - b->r_month;
+	return a->r_dayofmonth - b->r_dayofmonth;
+}
+
+static int
+stringzone(char *result, struct zone const *zpfirst, ptrdiff_t zonecount)
 {
 	register const struct zone *	zp;
 	register struct rule *		rp;
 	register struct rule *		stdrp;
 	register struct rule *		dstrp;
-	register int			i;
-	register const char *		abbrvar;
+	register ptrdiff_t		i;
+	register int			compat = 0;
+	register int			c;
+	size_t				len;
+	int				offsetlen;
+	struct rule			stdr, dstr;
+	int dstcmp;
+	struct rule *lastrp[2] = { NULL, NULL };
+	struct zone zstr[2];
+	struct zone const *stdzp;
+	struct zone const *dstzp;
 
 	result[0] = '\0';
+
+	/* Internet RFC 8536 section 5.1 says to use an empty TZ string if
+	   future timestamps are truncated.  */
+	if (hi_time < max_time)
+	  return -1;
+
 	zp = zpfirst + zonecount - 1;
-	stdrp = dstrp = NULL;
 	for (i = 0; i < zp->z_nrules; ++i) {
+		struct rule **last;
+		int cmp;
 		rp = &zp->z_rules[i];
-		if (rp->r_hiwasnum || rp->r_hiyear != INT_MAX)
-			continue;
-		if (rp->r_yrtype != NULL)
-			continue;
-		if (rp->r_stdoff == 0) {
-			if (stdrp == NULL)
-				stdrp = rp;
-			else	return;
-		} else {
-			if (dstrp == NULL)
-				dstrp = rp;
-			else	return;
-		}
+		last = &lastrp[rp->r_isdst];
+		cmp = rule_cmp(*last, rp);
+		if (cmp < 0)
+		  *last = rp;
+		else if (cmp == 0)
+		  return -1;
 	}
-	if (stdrp == NULL && dstrp == NULL) {
-		/*
-		** There are no rules running through "max".
-		** Let's find the latest rule.
-		*/
-		for (i = 0; i < zp->z_nrules; ++i) {
-			rp = &zp->z_rules[i];
-			if (stdrp == NULL || rp->r_hiyear > stdrp->r_hiyear ||
-				(rp->r_hiyear == stdrp->r_hiyear &&
-				rp->r_month > stdrp->r_month))
-					stdrp = rp;
-		}
-		if (stdrp != NULL && stdrp->r_stdoff != 0)
-			return;	/* We end up in DST (a POSIX no-no). */
-		/*
-		** 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;
+	stdrp = lastrp[false];
+	dstrp = lastrp[true];
+	dstcmp = zp->z_nrules ? rule_cmp(dstrp, stdrp) : zp->z_isdst ? 1 : -1;
+	stdzp = dstzp = zp;
+
+	if (dstcmp < 0) {
+	  /* Standard time all year.  */
+	  dstrp = NULL;
+	} else if (0 < dstcmp) {
+	  /* DST all year.  Use an abbreviation like
+	     "XXX3EDT4,0/0,J365/23" for EDT (-04) all year.  */
+	  zic_t save = dstrp ? dstrp->r_save : zp->z_save;
+	  if (0 <= save)
+	    {
+	      /* Positive DST, the typical case for all-year DST.
+		 Fake a timezone with negative DST.  */
+	      stdzp = &zstr[0];
+	      dstzp = &zstr[1];
+	      zstr[0].z_stdoff = zp->z_stdoff + 2 * save;
+	      zstr[0].z_format = "XXX";  /* Any 3 letters will do.  */
+	      zstr[0].z_format_specifier = 0;
+	      zstr[1].z_stdoff = zstr[0].z_stdoff;
+	      zstr[1].z_format = zp->z_format;
+	      zstr[1].z_format_specifier = zp->z_format_specifier;
+	    }
+	  dstr.r_month = TM_JANUARY;
+	  dstr.r_dycode = DC_DOM;
+	  dstr.r_dayofmonth = 1;
+	  dstr.r_tod = 0;
+	  dstr.r_todisstd = dstr.r_todisut = false;
+	  dstr.r_isdst = true;
+	  dstr.r_save = save < 0 ? save : -save;
+	  dstr.r_abbrvar = dstrp ? dstrp->r_abbrvar : NULL;
+	  stdr.r_month = TM_DECEMBER;
+	  stdr.r_dycode = DC_DOM;
+	  stdr.r_dayofmonth = 31;
+	  stdr.r_tod = SECSPERDAY + dstr.r_save;
+	  stdr.r_todisstd = stdr.r_todisut = false;
+	  stdr.r_isdst = false;
+	  stdr.r_save = 0;
+	  stdr.r_abbrvar = save < 0 && stdrp ? stdrp->r_abbrvar : NULL;
+	  dstrp = &dstr;
+	  stdrp = &stdr;
 	}
-	if (stdrp == NULL && (zp->z_nrules != 0 || zp->z_stdoff != 0))
-		return;
-	abbrvar = (stdrp == NULL) ? "" : stdrp->r_abbrvar;
-	doabbr(result, zp->z_format, abbrvar, FALSE, TRUE);
-	if (stringoffset(end(result), -zp->z_gmtoff) != 0) {
+	len = doabbr(result, stdzp, stdrp ? stdrp->r_abbrvar : NULL,
+		     false, 0, true);
+	offsetlen = stringoffset(result + len, - stdzp->z_stdoff);
+	if (! offsetlen) {
 		result[0] = '\0';
-		return;
+		return -1;
 	}
+	len += offsetlen;
 	if (dstrp == NULL)
-		return;
-	doabbr(end(result), zp->z_format, dstrp->r_abbrvar, TRUE, TRUE);
-	if (dstrp->r_stdoff != SECSPERMIN * MINSPERHOUR)
-		if (stringoffset(end(result),
-			-(zp->z_gmtoff + dstrp->r_stdoff)) != 0) {
-				result[0] = '\0';
-				return;
-		}
-	(void) strcat(result, ",");
-	if (stringrule(result, dstrp, dstrp->r_stdoff, zp->z_gmtoff) != 0) {
+		return compat;
+	len += doabbr(result + len, dstzp, dstrp->r_abbrvar,
+		      dstrp->r_isdst, dstrp->r_save, true);
+	if (dstrp->r_save != SECSPERMIN * MINSPERHOUR) {
+	  offsetlen = stringoffset(result + len,
+				   - (dstzp->z_stdoff + dstrp->r_save));
+	  if (! offsetlen) {
+	    result[0] = '\0';
+	    return -1;
+	  }
+	  len += offsetlen;
+	}
+	result[len++] = ',';
+	c = stringrule(result + len, dstrp, dstrp->r_save, stdzp->z_stdoff);
+	if (c < 0) {
 		result[0] = '\0';
-		return;
+		return -1;
 	}
-	(void) strcat(result, ",");
-	if (stringrule(result, stdrp, dstrp->r_stdoff, zp->z_gmtoff) != 0) {
+	if (compat < c)
+		compat = c;
+	len += strlen(result + len);
+	result[len++] = ',';
+	c = stringrule(result + len, stdrp, dstrp->r_save, stdzp->z_stdoff);
+	if (c < 0) {
 		result[0] = '\0';
-		return;
+		return -1;
 	}
+	if (compat < c)
+		compat = c;
+	return compat;
 }
 
 static void
-outzone(zpfirst, zonecount)
-const struct zone * const	zpfirst;
-const int			zonecount;
+outzone(const struct zone *zpfirst, ptrdiff_t zonecount)
 {
-	register const struct zone *	zp;
-	register struct rule *		rp;
-	register int			i, j;
-	register int			usestart, useuntil;
+	register ptrdiff_t		i, j;
 	register zic_t			starttime, untiltime;
-	register long			gmtoff;
-	register long			stdoff;
-	register int			year;
-	register long			startoff;
-	register int			startttisstd;
-	register int			startttisgmt;
-	register int			type;
+	register bool			startttisstd;
+	register bool			startttisut;
 	register char *			startbuf;
 	register char *			ab;
 	register char *			envvar;
 	register int			max_abbr_len;
 	register int			max_envvar_len;
-	register int			prodstic; /* all rules are min to max */
+	register bool			prodstic; /* all rules are min to max */
+	register int			compat;
+	register bool			do_extend;
+	register char			version;
+	ptrdiff_t lastatmax = -1;
+	zic_t max_year0;
+	int defaulttype = -1;
+
+	check_for_signal();
 
 	max_abbr_len = 2 + max_format_len + max_abbrvar_len;
 	max_envvar_len = 2 * max_abbr_len + 5 * 9;
@@ -2038,47 +2873,69 @@ const int			zonecount;
 	** Thanks to Earl Chew
 	** for noting the need to unconditionally initialize startttisstd.
 	*/
-	startttisstd = FALSE;
-	startttisgmt = FALSE;
+	startttisstd = false;
+	startttisut = false;
 	min_year = max_year = EPOCH_YEAR;
 	if (leapseen) {
 		updateminmax(leapminyear);
-		updateminmax(leapmaxyear + (leapmaxyear < INT_MAX));
+		updateminmax(leapmaxyear + (leapmaxyear < ZIC_MAX));
 	}
 	for (i = 0; i < zonecount; ++i) {
-		zp = &zpfirst[i];
+		struct zone const *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];
+			struct rule *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;
+				prodstic = false;
 		}
 	}
 	/*
 	** Generate lots of data if a rule can't cover all future times.
 	*/
-	stringzone(envvar, zpfirst, zonecount);
-	if (noise && envvar[0] == '\0') {
-		register char *	wp;
-
-wp = ecpyalloc(_("no POSIX environment variable for zone"));
-		wp = ecatalloc(wp, " ");
-		wp = ecatalloc(wp, zpfirst->z_name);
-		warning(wp);
-		ifree(wp);
+	compat = stringzone(envvar, zpfirst, zonecount);
+	version = compat < 2013 ? '2' : '3';
+	do_extend = compat < 0;
+	if (noise) {
+		if (!*envvar)
+			warning("%s %s",
+				_("no POSIX environment variable for zone"),
+				zpfirst->z_name);
+		else if (compat != 0) {
+			/* Circa-COMPAT clients, and earlier clients, might
+			   not work for this zone when given dates before
+			   1970 or after 2038.  */
+			warning(_("%s: pre-%d clients may mishandle"
+				  " distant timestamps"),
+				zpfirst->z_name, compat);
+		}
 	}
-	if (envvar[0] == '\0') {
-		if (min_year >= INT_MIN + YEARSPERREPEAT)
-			min_year -= YEARSPERREPEAT;
-		else	min_year = INT_MIN;
-		if (max_year <= INT_MAX - YEARSPERREPEAT)
-			max_year += YEARSPERREPEAT;
-		else	max_year = INT_MAX;
+	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
@@ -2087,79 +2944,99 @@ wp = ecpyalloc(_("no POSIX environment variable for zone"));
 		*/
 		if (prodstic) {
 			min_year = 1900;
-			max_year = min_year + YEARSPERREPEAT;
+			max_year = min_year + years_of_observations;
 		}
 	}
-	/*
-	** For the benefit of older systems,
-	** generate data from 1900 through 2037.
-	*/
-	if (min_year > 1900)
+	max_year = max(max_year, (redundant_time / (SECSPERDAY * DAYSPERNYEAR)
+				  + EPOCH_YEAR + 1));
+	max_year0 = max_year;
+	if (want_bloat()) {
+	  /* For the benefit of older systems,
+	     generate data from 1900 through 2038.  */
+	  if (min_year > 1900)
 		min_year = 1900;
-	if (max_year < 2037)
-		max_year = 2037;
+	  if (max_year < 2038)
+		max_year = 2038;
+	}
+
+	if (min_time < lo_time || hi_time < max_time)
+	  unspecifiedtype = addtype(0, "-00", false, false, false);
+
 	for (i = 0; i < zonecount; ++i) {
+		struct rule *prevrp = NULL;
 		/*
 		** A guess that may well be corrected later.
 		*/
-		stdoff = 0;
-		zp = &zpfirst[i];
-		usestart = i > 0 && (zp - 1)->z_untiltime > min_time;
-		useuntil = i < (zonecount - 1);
+		zic_t save = 0;
+		struct zone const *zp = &zpfirst[i];
+		bool usestart = i > 0 && (zp - 1)->z_untiltime > min_time;
+		bool useuntil = i < (zonecount - 1);
+		zic_t stdoff = zp->z_stdoff;
+		zic_t startoff = stdoff;
+		zic_t prevktime;
+		INITIALIZE(prevktime);
 		if (useuntil && zp->z_untiltime <= min_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->z_format,
-				(char *) NULL, stdoff != 0, FALSE);
-			type = addtype(oadd(zp->z_gmtoff, stdoff),
-				startbuf, stdoff != 0, startttisstd,
-				startttisgmt);
+			int type;
+			save = zp->z_save;
+			doabbr(startbuf, zp, NULL, zp->z_isdst, save, false);
+			type = addtype(oadd(zp->z_stdoff, save),
+				startbuf, zp->z_isdst, startttisstd,
+				startttisut);
 			if (usestart) {
 				addtt(starttime, type);
-				usestart = FALSE;
-			} else if (stdoff != 0)
-				addtt(min_time, type);
-		} else for (year = min_year; year <= max_year; ++year) {
+				usestart = false;
+			} else
+				defaulttype = type;
+		} else {
+		  zic_t year;
+		  for (year = min_year; year <= max_year; ++year) {
 			if (useuntil && year > zp->z_untilrule.r_hiyear)
 				break;
 			/*
 			** Mark which rules to do in the current year.
 			** For those to do, calculate rpytime(rp, year);
+			** The former TYPE field was also considered here.
 			*/
 			for (j = 0; j < zp->z_nrules; ++j) {
-				rp = &zp->z_rules[j];
+				zic_t one = 1;
+				zic_t y2038_boundary = one << 31;
+				struct rule *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)
+						year <= rp->r_hiyear;
+				if (rp->r_todo) {
 					rp->r_temp = rpytime(rp, year);
+					rp->r_todo
+					  = (rp->r_temp < y2038_boundary
+					     || year <= max_year0);
+				}
 			}
 			for ( ; ; ) {
-				register int	k;
+				register ptrdiff_t k;
 				register zic_t	jtime, ktime;
-				register long	offset;
+				register zic_t	offset;
+				struct rule *rp;
+				int type;
 
 				INITIALIZE(ktime);
 				if (useuntil) {
 					/*
-					** Turn untiltime into UTC
-					** assuming the current gmtoff and
-					** stdoff values.
+					** Turn untiltime into UT
+					** assuming the current stdoff and
+					** save values.
 					*/
 					untiltime = zp->z_untiltime;
-					if (!zp->z_untilrule.r_todisgmt)
+					if (!zp->z_untilrule.r_todisut)
 						untiltime = tadd(untiltime,
-							-gmtoff);
+								 -stdoff);
 					if (!zp->z_untilrule.r_todisstd)
 						untiltime = tadd(untiltime,
-							-stdoff);
+								 -save);
 				}
 				/*
 				** Find the rule (of those to do, if any)
@@ -2167,15 +3044,15 @@ wp = ecpyalloc(_("no POSIX environment variable for zone"));
 				*/
 				k = -1;
 				for (j = 0; j < zp->z_nrules; ++j) {
-					rp = &zp->z_rules[j];
-					if (!rp->r_todo)
+					struct rule *r = &zp->z_rules[j];
+					if (!r->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;
+						r->r_filename, r->r_linenum);
+					offset = r->r_todisut ? 0 : stdoff;
+					if (!r->r_todisstd)
+						offset = oadd(offset, save);
+					jtime = r->r_temp;
 					if (jtime == min_time ||
 						jtime == max_time)
 							continue;
@@ -2183,142 +3060,179 @@ wp = ecpyalloc(_("no POSIX environment variable for zone"));
 					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,
+					       r->r_filename, r->r_linenum);
+					  warning("%s", dup_rules_msg);
+					  r = &zp->z_rules[k];
+					  eats(zp->z_filename, zp->z_linenum,
+					       r->r_filename, r->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)
+				rp->r_todo = false;
+				if (useuntil && ktime >= untiltime) {
+					if (!*startbuf
+					    && (oadd(zp->z_stdoff, rp->r_save)
+						== startoff))
+					  doabbr(startbuf, zp, rp->r_abbrvar,
+						 rp->r_isdst, rp->r_save,
+						 false);
 					break;
-				stdoff = rp->r_stdoff;
+				}
+				save = rp->r_save;
 				if (usestart && ktime == starttime)
-					usestart = FALSE;
+					usestart = false;
 				if (usestart) {
 					if (ktime < starttime) {
-						startoff = oadd(zp->z_gmtoff,
-							stdoff);
-						doabbr(startbuf, zp->z_format,
+						startoff = oadd(zp->z_stdoff,
+								save);
+						doabbr(startbuf, zp,
 							rp->r_abbrvar,
-							rp->r_stdoff != 0,
-							FALSE);
+							rp->r_isdst,
+							rp->r_save,
+							false);
 						continue;
 					}
-					if (*startbuf == '\0' &&
-						startoff == oadd(zp->z_gmtoff,
-						stdoff)) {
+					if (*startbuf == '\0'
+					    && startoff == oadd(zp->z_stdoff,
+								save)) {
 							doabbr(startbuf,
-								zp->z_format,
+								zp,
 								rp->r_abbrvar,
-								rp->r_stdoff !=
-								0,
-								FALSE);
+								rp->r_isdst,
+								rp->r_save,
+								false);
 					}
 				}
 				eats(zp->z_filename, zp->z_linenum,
 					rp->r_filename, rp->r_linenum);
-				doabbr(ab, zp->z_format, rp->r_abbrvar,
-					rp->r_stdoff != 0, FALSE);
-				offset = oadd(zp->z_gmtoff, rp->r_stdoff);
-				type = addtype(offset, ab, rp->r_stdoff != 0,
-					rp->r_todisstd, rp->r_todisgmt);
+				doabbr(ab, zp, rp->r_abbrvar,
+				       rp->r_isdst, rp->r_save, false);
+				offset = oadd(zp->z_stdoff, rp->r_save);
+				if (!want_bloat() && !useuntil && !do_extend
+				    && prevrp && lo_time <= prevktime
+				    && redundant_time <= ktime
+				    && rp->r_hiyear == ZIC_MAX
+				    && prevrp->r_hiyear == ZIC_MAX)
+				  break;
+				type = addtype(offset, ab, rp->r_isdst,
+					rp->r_todisstd, rp->r_todisut);
+				if (defaulttype < 0 && !rp->r_isdst)
+				  defaulttype = type;
+				if (rp->r_hiyear == ZIC_MAX
+				    && ! (0 <= lastatmax
+					  && ktime < attypes[lastatmax].at))
+				  lastatmax = timecnt;
 				addtt(ktime, type);
+				prevrp = rp;
+				prevktime = ktime;
 			}
+		  }
 		}
 		if (usestart) {
-			if (*startbuf == '\0' &&
-				zp->z_format != NULL &&
-				strchr(zp->z_format, '%') == NULL &&
-				strchr(zp->z_format, '/') == NULL)
-					(void) strcpy(startbuf, zp->z_format);
+			bool isdst = startoff != zp->z_stdoff;
+			if (*startbuf == '\0' && zp->z_format)
+			  doabbr(startbuf, zp, disable_percent_s,
+				 isdst, save, false);
 			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));
+			else {
+			  int type = addtype(startoff, startbuf, isdst,
+					     startttisstd, startttisut);
+			  if (defaulttype < 0 && !isdst)
+			    defaulttype = type;
+			  addtt(starttime, type);
+			}
 		}
 		/*
 		** Now we may get to set starttime for the next zone line.
 		*/
 		if (useuntil) {
 			startttisstd = zp->z_untilrule.r_todisstd;
-			startttisgmt = zp->z_untilrule.r_todisgmt;
+			startttisut = zp->z_untilrule.r_todisut;
 			starttime = zp->z_untiltime;
 			if (!startttisstd)
-				starttime = tadd(starttime, -stdoff);
-			if (!startttisgmt)
-				starttime = tadd(starttime, -gmtoff);
+			  starttime = tadd(starttime, -save);
+			if (!startttisut)
+			  starttime = tadd(starttime, -stdoff);
 		}
 	}
-	writezone(zpfirst->z_name, envvar);
-	ifree(startbuf);
-	ifree(ab);
-	ifree(envvar);
+	if (defaulttype < 0)
+	  defaulttype = 0;
+	if (0 <= lastatmax)
+	  attypes[lastatmax].dontmerge = true;
+	if (do_extend) {
+		/*
+		** If we're extending the explicitly listed observations
+		** for 400 years because we can't fill the POSIX-TZ field,
+		** check whether we actually ended up explicitly listing
+		** observations through that period.  If there aren't any
+		** near the end of the 400-year period, add a redundant
+		** one at the end of the final year, to make it clear
+		** that we are claiming to have definite knowledge of
+		** the lack of transitions up to that point.
+		*/
+		struct rule xr;
+		struct attype *lastat;
+		xr.r_month = TM_JANUARY;
+		xr.r_dycode = DC_DOM;
+		xr.r_dayofmonth = 1;
+		xr.r_tod = 0;
+		for (lastat = attypes, i = 1; i < timecnt; i++)
+			if (attypes[i].at > lastat->at)
+				lastat = &attypes[i];
+		if (!lastat || lastat->at < rpytime(&xr, max_year - 1)) {
+			addtt(rpytime(&xr, max_year + 1),
+			      lastat ? lastat->type : defaulttype);
+			attypes[timecnt - 1].dontmerge = true;
+		}
+	}
+	writezone(zpfirst->z_name, envvar, version, defaulttype);
+	free(startbuf);
+	free(ab);
+	free(envvar);
 }
 
 static void
-addtt(starttime, type)
-const zic_t	starttime;
-int		type;
+addtt(zic_t starttime, int type)
 {
-	if (starttime <= min_time ||
-		(timecnt == 1 && attypes[0].at < min_time)) {
-		gmtoffs[0] = gmtoffs[type];
-		isdsts[0] = isdsts[type];
-		ttisstds[0] = ttisstds[type];
-		ttisgmts[0] = ttisgmts[type];
-		if (abbrinds[type] != 0)
-			(void) strcpy(chars, &chars[abbrinds[type]]);
-		abbrinds[0] = 0;
-		charcnt = strlen(chars) + 1;
-		typecnt = 1;
-		timecnt = 0;
-		type = 0;
-	}
-	if (timecnt >= TZ_MAX_TIMES) {
-		error(_("too many transitions?!"));
-		exit(EXIT_FAILURE);
-	}
+	attypes = growalloc(attypes, sizeof *attypes, timecnt, &timecnt_alloc);
 	attypes[timecnt].at = starttime;
+	attypes[timecnt].dontmerge = false;
 	attypes[timecnt].type = type;
 	++timecnt;
 }
 
 static int
-addtype(gmtoff, abbr, isdst, ttisstd, ttisgmt)
-const long		gmtoff;
-const char * const	abbr;
-const int		isdst;
-const int		ttisstd;
-const int		ttisgmt;
+addtype(zic_t utoff, char const *abbr, bool isdst, bool ttisstd, bool ttisut)
 {
 	register int	i, j;
 
-	if (isdst != TRUE && isdst != FALSE) {
-		error(_("internal error - addtype called with bad isdst"));
-		exit(EXIT_FAILURE);
-	}
-	if (ttisstd != TRUE && ttisstd != FALSE) {
-		error(_("internal error - addtype called with bad ttisstd"));
+	if (! (-1L - 2147483647L <= utoff && utoff <= 2147483647L)) {
+		error(_("UT offset out of range"));
 		exit(EXIT_FAILURE);
 	}
-	if (ttisgmt != TRUE && ttisgmt != FALSE) {
-		error(_("internal error - addtype called with bad ttisgmt"));
-		exit(EXIT_FAILURE);
-	}
-	/*
-	** 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;
+	if (!want_bloat())
+	  ttisstd = ttisut = false;
+
+	for (j = 0; j < charcnt; ++j)
+		if (strcmp(&chars[j], abbr) == 0)
+			break;
+	if (j == charcnt)
+		newabbr(abbr);
+	else {
+	  /* If there's already an entry, return its index.  */
+	  for (i = 0; i < typecnt; i++)
+	    if (utoff == utoffs[i] && isdst == isdsts[i] && j == desigidx[i]
+		&& ttisstd == ttisstds[i] && ttisut == ttisuts[i])
+	      return i;
 	}
 	/*
 	** There isn't one; add a new one, unless there are already too
@@ -2328,145 +3242,178 @@ const int		ttisgmt;
 		error(_("too many local time types"));
 		exit(EXIT_FAILURE);
 	}
-	if (! (-1L - 2147483647L <= gmtoff && gmtoff <= 2147483647L)) {
-		error(_("UTC offset out of range"));
-		exit(EXIT_FAILURE);
-	}
-	gmtoffs[i] = gmtoff;
+	i = typecnt++;
+	utoffs[i] = utoff;
 	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;
+	ttisuts[i] = ttisut;
+	desigidx[i] = j;
 	return i;
 }
 
 static void
-leapadd(t, positive, rolling, count)
-const zic_t	t;
-const int	positive;
-const int	rolling;
-int		count;
+leapadd(zic_t t, int correction, int rolling)
 {
-	register int	i, j;
+	register int i;
 
-	if (leapcnt + (positive ? count : 1) > TZ_MAX_LEAPS) {
+	if (TZ_MAX_LEAPS <= leapcnt) {
 		error(_("too many leap seconds"));
 		exit(EXIT_FAILURE);
 	}
+	if (rolling && (lo_time != min_time || hi_time != max_time)) {
+	  error(_("Rolling leap seconds not supported with -r"));
+	  exit(EXIT_FAILURE);
+	}
 	for (i = 0; i < leapcnt; ++i)
-		if (t <= trans[i]) {
-			if (t == trans[i]) {
-				error(_("repeated leap second moment"));
-				exit(EXIT_FAILURE);
-			}
+		if (t <= trans[i])
 			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 ? 1L : eitol(-count);
-		roll[i] = rolling;
-		++leapcnt;
-	} while (positive && --count != 0);
+	memmove(&trans[i + 1], &trans[i], (leapcnt - i) * sizeof *trans);
+	memmove(&corr[i + 1], &corr[i], (leapcnt - i) * sizeof *corr);
+	memmove(&roll[i + 1], &roll[i], (leapcnt - i) * sizeof *roll);
+	trans[i] = t;
+	corr[i] = correction;
+	roll[i] = rolling;
+	++leapcnt;
 }
 
 static void
 adjleap(void)
 {
 	register int	i;
-	register long	last = 0;
+	register zic_t	last = 0;
+	register zic_t	prevtrans = 0;
 
 	/*
 	** propagate leap seconds forward
 	*/
 	for (i = 0; i < leapcnt; ++i) {
+		if (trans[i] - prevtrans < 28 * SECSPERDAY) {
+		  error(_("Leap seconds too close together"));
+		  exit(EXIT_FAILURE);
+		}
+		prevtrans = trans[i];
 		trans[i] = tadd(trans[i], last);
 		last = corr[i] += last;
 	}
+
+	if (0 <= leapexpires) {
+	  leapexpires = oadd(leapexpires, last);
+	  if (! (leapcnt == 0 || (trans[leapcnt - 1] < leapexpires))) {
+	    error(_("last Leap time does not precede Expires time"));
+	    exit(EXIT_FAILURE);
+	  }
+	}
 }
 
-static int
-yearistype(year, type)
-const int		year;
-const char * const	type;
+/* Is A a space character in the C locale?  */
+static bool
+is_space(char a)
 {
-	static char *	buf;
-	int		result;
+	switch (a) {
+	  default:
+		return false;
+	  case ' ': case '\f': case '\n': case '\r': case '\t': case '\v':
+		return true;
+	}
+}
 
-	if (type == NULL || *type == '\0')
-		return TRUE;
-	buf = erealloc(buf, (int) (132 + strlen(yitcommand) + strlen(type)));
-	(void) 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;
+/* 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;
 	}
-	error(_("Wild result from command execution"));
-	(void) fprintf(stderr, _("%s: command was '%s', result was %d\n"),
-		progname, buf, result);
-	for ( ; ; )
-		exit(EXIT_FAILURE);
 }
 
-static int
-lowerit(a)
-int	a;
+/* If A is an uppercase character in the C locale, return its lowercase
+   counterpart.  Otherwise, return A.  */
+static char
+lowerit(char a)
 {
-	a = (unsigned char) a;
-	return (isascii(a) && isupper(a)) ? tolower(a) : 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';
+	}
 }
 
-static int
-ciequal(ap, bp)		/* case-insensitive equality */
-register const char *	ap;
-register const char *	bp;
+/* case-insensitive equality */
+static ATTRIBUTE_PURE bool
+ciequal(register const char *ap, register const char *bp)
 {
 	while (lowerit(*ap) == lowerit(*bp++))
 		if (*ap++ == '\0')
-			return TRUE;
-	return FALSE;
+			return true;
+	return false;
 }
 
-static int
-itsabbr(abbr, word)
-register const char *	abbr;
-register const char *	word;
+static ATTRIBUTE_PURE bool
+itsabbr(register const char *abbr, register const char *word)
 {
 	if (lowerit(*abbr) != lowerit(*word))
-		return FALSE;
+		return false;
 	++word;
 	while (*++abbr != '\0')
 		do {
 			if (*word == '\0')
-				return FALSE;
+				return false;
 		} while (lowerit(*word++) != lowerit(*abbr));
-	return TRUE;
+	return true;
+}
+
+/* Return true if ABBR is an initial prefix of WORD, ignoring ASCII case.  */
+
+static ATTRIBUTE_PURE bool
+ciprefix(char const *abbr, char const *word)
+{
+  do
+    if (!*abbr)
+      return true;
+  while (lowerit(*abbr++) == lowerit(*word++));
+
+  return false;
 }
 
 static const struct lookup *
-byword(word, table)
-register const char * const		word;
-register const struct lookup * const	table;
+byword(const char *word, const struct lookup *table)
 {
 	register const struct lookup *	foundlp;
 	register const struct lookup *	lp;
 
 	if (word == NULL || table == NULL)
 		return NULL;
+
+	/* If TABLE is LASTS and the word starts with "last" followed
+	   by a non-'-', skip the "last" and look in WDAY_NAMES instead.
+	   Warn about any usage of the undocumented prefix "last-".  */
+	if (table == lasts && ciprefix("last", word) && word[4]) {
+	  if (word[4] == '-')
+	    warning(_("\"%s\" is undocumented; use \"last%s\" instead"),
+		    word, word + 5);
+	  else {
+	    word += 4;
+	    table = wday_names;
+	  }
+	}
+
 	/*
 	** Look for exact match.
 	*/
@@ -2478,34 +3425,42 @@ register const struct lookup * const	table;
 	*/
 	foundlp = NULL;
 	for (lp = table; lp->l_word != NULL; ++lp)
-		if (itsabbr(word, lp->l_word)) {
+		if (ciprefix(word, lp->l_word)) {
 			if (foundlp == NULL)
 				foundlp = lp;
 			else	return NULL;	/* multiple inexact matches */
 		}
+
+	if (foundlp && noise) {
+	  /* Warn about any backward-compatibility issue with pre-2017c zic.  */
+	  bool pre_2017c_match = false;
+	  for (lp = table; lp->l_word; lp++)
+	    if (itsabbr(word, lp->l_word)) {
+	      if (pre_2017c_match) {
+		warning(_("\"%s\" is ambiguous in pre-2017c zic"), word);
+		break;
+	      }
+	      pre_2017c_match = true;
+	    }
+	}
+
 	return foundlp;
 }
 
-static char **
-getfields(cp)
-register char *	cp;
+static int
+getfields(char *cp, char **array, int arrayelts)
 {
 	register char *		dp;
-	register char **	array;
 	register int		nsubs;
 
-	if (cp == NULL)
-		return NULL;
-	array = (char **) (void *)
-		emalloc((int) ((strlen(cp) + 1) * sizeof *array));
 	nsubs = 0;
 	for ( ; ; ) {
-		while (isascii((unsigned char) *cp) &&
-			isspace((unsigned char) *cp))
+		char *dstart;
+		while (is_space(*cp))
 				++cp;
 		if (*cp == '\0' || *cp == '#')
 			break;
-		array[nsubs++] = dp = cp;
+		dstart = dp = cp;
 		do {
 			if ((*dp = *cp++) != '"')
 				++dp;
@@ -2513,89 +3468,93 @@ register char *	cp;
 				if (*dp != '\0')
 					++dp;
 				else {
-					error(_(
-						"Odd number of quotation marks"
-						));
-					exit(1);
+				  error(_("Odd number of quotation marks"));
+				  exit(EXIT_FAILURE);
 				}
-		} while (*cp != '\0' && *cp != '#' &&
-			(!isascii(*cp) || !isspace((unsigned char) *cp)));
-		if (isascii(*cp) && isspace((unsigned char) *cp))
+		} while (*cp && *cp != '#' && !is_space(*cp));
+		if (is_space(*cp))
 			++cp;
 		*dp = '\0';
+		if (nsubs == arrayelts) {
+		  error(_("Too many input fields"));
+		  exit(EXIT_FAILURE);
+		}
+		array[nsubs++] = dstart + (*dstart == '-' && dp == dstart + 1);
 	}
-	array[nsubs] = NULL;
-	return array;
+	return nsubs;
 }
 
-static long
-oadd(t1, t2)
-const long	t1;
-const long	t2;
+static _Noreturn void
+time_overflow(void)
 {
-	register long	t;
-
-	t = t1 + t2;
-	if ((t2 > 0 && t <= t1) || (t2 < 0 && t >= t1)) {
-		error(_("time overflow"));
-		exit(EXIT_FAILURE);
-	}
-	return t;
+  error(_("time overflow"));
+  exit(EXIT_FAILURE);
 }
 
-static zic_t
-tadd(t1, t2)
-const zic_t	t1;
-const long	t2;
+static ATTRIBUTE_PURE zic_t
+oadd(zic_t t1, zic_t t2)
 {
-	register zic_t	t;
+	if (t1 < 0 ? t2 < ZIC_MIN - t1 : ZIC_MAX - t1 < t2)
+	  time_overflow();
+	return t1 + t2;
+}
 
-	if (t1 == max_time && t2 > 0)
-		return max_time;
-	if (t1 == min_time && t2 < 0)
-		return min_time;
-	t = t1 + t2;
-	if ((t2 > 0 && t <= t1) || (t2 < 0 && t >= t1)) {
-		error(_("time overflow"));
-		exit(EXIT_FAILURE);
-	}
-	return t;
+static ATTRIBUTE_PURE zic_t
+tadd(zic_t t1, zic_t t2)
+{
+  if (t1 < 0) {
+    if (t2 < min_time - t1) {
+      if (t1 != min_time)
+	time_overflow();
+      return min_time;
+    }
+  } else {
+    if (max_time - t1 < t2) {
+      if (t1 != max_time)
+	time_overflow();
+      return max_time;
+    }
+  }
+  return t1 + t2;
 }
 
 /*
-** Given a rule, and a year, compute the date - in seconds since January 1,
-** 1970, 00:00 LOCAL time - in that year that the rule refers to.
+** 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(rp, wantedy)
-register const struct rule * const	rp;
-register const int			wantedy;
+rpytime(const struct rule *rp, zic_t wantedy)
 {
-	register int	y, m, i;
-	register long	dayoff;			/* with a nod to Margaret O. */
-	register zic_t	t;
+	register int	m, i;
+	register zic_t	dayoff;			/* with a nod to Margaret O. */
+	register zic_t	t, y;
+	int yrem;
 
-	if (wantedy == INT_MIN)
+	if (wantedy == ZIC_MIN)
 		return min_time;
-	if (wantedy == INT_MAX)
+	if (wantedy == ZIC_MAX)
 		return max_time;
-	dayoff = 0;
 	m = TM_JANUARY;
 	y = EPOCH_YEAR;
+
+	/* dayoff = floor((wantedy - y) / YEARSPERREPEAT) * DAYSPERREPEAT,
+	   sans overflow.  */
+	yrem = wantedy % YEARSPERREPEAT - y % YEARSPERREPEAT;
+	dayoff = ((wantedy / YEARSPERREPEAT - y / YEARSPERREPEAT
+		   + yrem / YEARSPERREPEAT - (yrem % YEARSPERREPEAT < 0))
+		  * DAYSPERREPEAT);
+	/* wantedy = y + ((wantedy - y) mod YEARSPERREPEAT), sans overflow.  */
+	wantedy = y + (yrem + 2 * YEARSPERREPEAT) % YEARSPERREPEAT;
+
 	while (wantedy != y) {
-		if (wantedy > y) {
-			i = len_years[isleap(y)];
-			++y;
-		} else {
-			--y;
-			i = -len_years[isleap(y)];
-		}
-		dayoff = oadd(dayoff, eitol(i));
+		i = len_years[isleap(y)];
+		dayoff = oadd(dayoff, i);
+		y++;
 	}
 	while (m != rp->r_month) {
 		i = len_months[isleap(y)][m];
-		dayoff = oadd(dayoff, eitol(i));
+		dayoff = oadd(dayoff, i);
 		++m;
 	}
 	i = rp->r_dayofmonth;
@@ -2608,37 +3567,28 @@ register const int			wantedy;
 		}
 	}
 	--i;
-	dayoff = oadd(dayoff, eitol(i));
+	dayoff = oadd(dayoff, i);
 	if (rp->r_dycode == DC_DOWGEQ || rp->r_dycode == DC_DOWLEQ) {
-		register long	wday;
-
-#define LDAYSPERWEEK	((long) DAYSPERWEEK)
-		wday = eitol(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 != eitol(rp->r_wday))
+		zic_t wday = ((EPOCH_WDAY + dayoff % DAYSPERWEEK + DAYSPERWEEK)
+			      % DAYSPERWEEK);
+		while (wday != rp->r_wday)
 			if (rp->r_dycode == DC_DOWGEQ) {
-				dayoff = oadd(dayoff, (long) 1);
-				if (++wday >= LDAYSPERWEEK)
+				dayoff = oadd(dayoff, 1);
+				if (++wday >= DAYSPERWEEK)
 					wday = 0;
 				++i;
 			} else {
-				dayoff = oadd(dayoff, (long) -1);
+				dayoff = oadd(dayoff, -1);
 				if (--wday < 0)
-					wday = LDAYSPERWEEK - 1;
+					wday = DAYSPERWEEK - 1;
 				--i;
 			}
 		if (i < 0 || i >= len_months[isleap(y)][m]) {
 			if (noise)
-				warning(_("rule goes past start/end of month--\
+				warning(_("rule goes past start/end of month; \
 will not work with pre-2004 versions of zic"));
 		}
 	}
@@ -2651,121 +3601,90 @@ will not work with pre-2004 versions of zic"));
 }
 
 static void
-newabbr(string)
-const char * const	string;
+newabbr(const char *string)
 {
 	register int	i;
 
 	if (strcmp(string, GRANDPARENTED) != 0) {
 		register const char *	cp;
-		register char *		wp;
+		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;
-		wp = NULL;
-		while (isascii((unsigned char) *cp) &&
-			isalpha((unsigned char) *cp))
+		mp = NULL;
+		while (is_alpha(*cp) || ('0' <= *cp && *cp <= '9')
+		       || *cp == '-' || *cp == '+')
 				++cp;
-		if (cp - string == 0)
-wp = _("time zone abbreviation lacks alphabetic at start");
-		if (noise && cp - string > 3)
-wp = _("time zone abbreviation has more than 3 alphabetics");
+		if (noise && cp - string < 3)
+		  mp = _("time zone abbreviation has fewer than 3 characters");
 		if (cp - string > ZIC_MAX_ABBR_LEN_WO_WARN)
-wp = _("time zone abbreviation has too many alphabetics");
-		if (wp == NULL && (*cp == '+' || *cp == '-')) {
-			++cp;
-			if (isascii((unsigned char) *cp) &&
-				isdigit((unsigned char) *cp))
-					if (*cp++ == '1' &&
-						*cp >= '0' && *cp <= '4')
-							++cp;
-		}
+		  mp = _("time zone abbreviation has too many characters");
 		if (*cp != '\0')
-wp = _("time zone abbreviation differs from POSIX standard");
-		if (wp != NULL) {
-			wp = ecpyalloc(wp);
-			wp = ecatalloc(wp, " (");
-			wp = ecatalloc(wp, string);
-			wp = ecatalloc(wp, ")");
-			warning(wp);
-			ifree(wp);
-		}
+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) strcpy(&chars[charcnt], string);
-	charcnt += eitol(i);
+	strcpy(&chars[charcnt], string);
+	charcnt += i;
 }
 
-static int
-mkdirs(argname)
-char *		argname;
+/* Ensure that the directories of ARGNAME exist, by making any missing
+   ones.  If ANCESTORS, do this only for ARGNAME's ancestors; otherwise,
+   do it for ARGNAME too.  Exit with failure if there is trouble.
+   Do not consider an existing file to be trouble.  */
+static void
+mkdirs(char const *argname, bool ancestors)
 {
 	register char *	name;
 	register char *	cp;
 
-	if (argname == NULL || *argname == '\0')
-		return 0;
 	cp = name = ecpyalloc(argname);
-	while ((cp = strchr(cp + 1, '/')) != 0) {
-		*cp = '\0';
-#ifndef unix
+
+	/* On MS-Windows systems, do not worry about drive letters or
+	   backslashes, as this should suffice in practice.  Time zone
+	   names do not use drive letters and backslashes.  If the -d
+	   option of zic does not name an already-existing directory,
+	   it can use slashes to separate the already-existing
+	   ancestor prefix from the to-be-created subdirectories.  */
+
+	/* Do not mkdir a root directory, as it must exist.  */
+	while (*cp == '/')
+	  cp++;
+
+	while (cp && ((cp = strchr(cp, '/')) || !ancestors)) {
+		if (cp)
+		  *cp = '\0';
 		/*
-		** DOS drive specifier?
+		** 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 (isalpha((unsigned char) name[0]) &&
-			name[1] == ':' && name[2] == '\0') {
-				*cp = '/';
-				continue;
-		}
-#endif /* !defined unix */
-		if (!itsdir(name)) {
-			/*
-			** It doesn't seem to exist, so we try to create it.
-			** Creation may fail because of the directory being
-			** created by some other multiprocessor, so we get
-			** to do extra checking.
-			*/
-			if (mkdir(name, MKDIR_UMASK) != 0) {
-				const char *e = strerror(errno);
-
-				if (errno != EEXIST || !itsdir(name)) {
-					(void) fprintf(stderr,
-_("%s: Can't create directory %s: %s\n"),
-						progname, name, e);
-					ifree(name);
-					return -1;
-				}
+		if (mkdir(name, MKDIR_UMASK) != 0) {
+			/* Do not report an error if err == EEXIST, because
+			   some other process might have made the directory
+			   in the meantime.  Likewise for ENOSYS, because
+			   Solaris 10 mkdir fails with ENOSYS if the
+			   directory is an automounted mount point.
+			   Likewise for EACCES, since mkdir can fail
+			   with EACCES merely because the parent directory
+			   is unwritable.  Likewise for most other error
+			   numbers.  */
+			int err = errno;
+			if (err == ELOOP || err == ENAMETOOLONG
+			    || err == ENOENT || err == ENOTDIR) {
+				error(_("%s: Can't create directory %s: %s"),
+				      progname, name, strerror(err));
+				exit(EXIT_FAILURE);
 			}
 		}
-		*cp = '/';
-	}
-	ifree(name);
-	return 0;
-}
-
-static long
-eitol(i)
-const int	i;
-{
-	long	l;
-
-	l = i;
-	if ((i < 0 && l >= 0) || (i == 0 && l != 0) || (i > 0 && l <= 0)) {
-		(void) fprintf(stderr,
-			_("%s: %d did not sign extend correctly\n"),
-			progname, i);
-		exit(EXIT_FAILURE);
+		if (cp)
+		  *cp++ = '/';
 	}
-	return l;
+	free(name);
 }
-
-/*
-** UNIX was a registered trademark of The Open Group in 2003.
-*/