Revert r256095, r256120 (partial), r256121:

r256095:
 - Add gnu/usr.bin/rcs back to the base system.

r256120:
 - Add WITHOUT_RCS back to src.conf.5.

r256121:
 - Remove UPDATING entry regarding gnu/usr.bin/rcs removal.

Requested by:	many
Approved by:	re (marius)
Discussed with:	core

1 files changed, 344 insertions, 0 deletions

diff --git a/gnu/usr.bin/rcs/lib/maketime.c b/gnu/usr.bin/rcs/lib/maketime.c
new file mode 100644
index 0000000..0f83bf5
--- /dev/null
+++ b/gnu/usr.bin/rcs/lib/maketime.c
@@ -0,0 +1,344 @@
+/* Convert struct partime into time_t.  */
+
+/* Copyright 1992, 1993, 1994, 1995 Paul Eggert
+   Distributed under license by the Free Software Foundation, Inc.
+
+This file is part of RCS.
+
+RCS is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+RCS is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with RCS; see the file COPYING.
+If not, write to the Free Software Foundation,
+59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+Report problems and direct all questions to:
+
+    rcs-bugs@cs.purdue.edu
+
+*/
+
+#if has_conf_h
+#	include "conf.h"
+#else
+#	ifdef __STDC__
+#		define P(x) x
+#	else
+#		define const
+#		define P(x) ()
+#	endif
+#	include <stdlib.h>
+#	include <time.h>
+#endif
+
+#include "partime.h"
+#include "maketime.h"
+
+char const maketId[]
+  = "$FreeBSD$";
+
+static int isleap P((int));
+static int month_days P((struct tm const*));
+static time_t maketime P((struct partime const*,time_t));
+
+/*
+* For maximum portability, use only localtime and gmtime.
+* Make no assumptions about the time_t epoch or the range of time_t values.
+* Avoid mktime because it's not universal and because there's no easy,
+* portable way for mktime to yield the inverse of gmtime.
+*/
+
+#define TM_YEAR_ORIGIN 1900
+
+	static int
+isleap(y)
+	int y;
+{
+	return (y&3) == 0  &&  (y%100 != 0 || y%400 == 0);
+}
+
+static int const month_yday[] = {
+	/* days in year before start of months 0-12 */
+	0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
+};
+
+/* Yield the number of days in TM's month.  */
+	static int
+month_days(tm)
+	struct tm const *tm;
+{
+	int m = tm->tm_mon;
+	return month_yday[m+1] - month_yday[m]
+		+ (m==1 && isleap(tm->tm_year + TM_YEAR_ORIGIN));
+}
+
+/*
+* Convert UNIXTIME to struct tm form.
+* Use gmtime if available and if !LOCALZONE, localtime otherwise.
+*/
+	struct tm *
+time2tm(unixtime, localzone)
+	time_t unixtime;
+	int localzone;
+{
+	struct tm *tm;
+#	if TZ_must_be_set
+		static char const *TZ;
+		if (!TZ  &&  !(TZ = getenv("TZ")))
+			faterror("The TZ environment variable is not set; please set it to your timezone");
+#	endif
+	if (localzone  ||  !(tm = gmtime(&unixtime)))
+		tm = localtime(&unixtime);
+	return tm;
+}
+
+/* Yield A - B, measured in seconds.  */
+	time_t
+difftm(a, b)
+	struct tm const *a, *b;
+{
+	int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
+	int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
+	int difference_in_day_of_year = a->tm_yday - b->tm_yday;
+	int intervening_leap_days = (
+		((ay >> 2) - (by >> 2))
+		- (ay/100 - by/100)
+		+ ((ay/100 >> 2) - (by/100 >> 2))
+	);
+	time_t difference_in_years = ay - by;
+	time_t difference_in_days = (
+		difference_in_years*365
+		+ (intervening_leap_days + difference_in_day_of_year)
+	);
+	return
+		(
+			(
+				24*difference_in_days
+				+ (a->tm_hour - b->tm_hour)
+			)*60 + (a->tm_min - b->tm_min)
+		)*60 + (a->tm_sec - b->tm_sec);
+}
+
+/*
+* Adjust time T by adding SECONDS.  SECONDS must be at most 24 hours' worth.
+* Adjust only T's year, mon, mday, hour, min and sec members;
+* plus adjust wday if it is defined.
+*/
+	void
+adjzone(t, seconds)
+	register struct tm *t;
+	long seconds;
+{
+	/*
+	* This code can be off by a second if SECONDS is not a multiple of 60,
+	* if T is local time, and if a leap second happens during this minute.
+	* But this bug has never occurred, and most likely will not ever occur.
+	* Liberia, the last country for which SECONDS % 60 was nonzero,
+	* switched to UTC in May 1972; the first leap second was in June 1972.
+	*/
+	int leap_second = t->tm_sec == 60;
+	long sec = seconds + (t->tm_sec - leap_second);
+	if (sec < 0) {
+	    if ((t->tm_min -= (59-sec)/60) < 0) {
+		if ((t->tm_hour -= (59-t->tm_min)/60) < 0) {
+		    t->tm_hour += 24;
+		    if (TM_DEFINED(t->tm_wday)  &&  --t->tm_wday < 0)
+			t->tm_wday = 6;
+		    if (--t->tm_mday <= 0) {
+			if (--t->tm_mon < 0) {
+			    --t->tm_year;
+			    t->tm_mon = 11;
+			}
+			t->tm_mday = month_days(t);
+		    }
+		}
+		t->tm_min += 24 * 60;
+	    }
+	    sec += 24L * 60 * 60;
+	} else
+	    if (60 <= (t->tm_min += sec/60))
+		if (24 <= (t->tm_hour += t->tm_min/60)) {
+		    t->tm_hour -= 24;
+		    if (TM_DEFINED(t->tm_wday)  &&  ++t->tm_wday == 7)
+			t->tm_wday = 0;
+		    if (month_days(t) < ++t->tm_mday) {
+			if (11 < ++t->tm_mon) {
+			    ++t->tm_year;
+			    t->tm_mon = 0;
+			}
+			t->tm_mday = 1;
+		    }
+		}
+	t->tm_min %= 60;
+	t->tm_sec = (int) (sec%60) + leap_second;
+}
+
+/*
+* Convert TM to time_t, using localtime if LOCALZONE and gmtime otherwise.
+* Use only TM's year, mon, mday, hour, min, and sec members.
+* Ignore TM's old tm_yday and tm_wday, but fill in their correct values.
+* Yield -1 on failure (e.g. a member out of range).
+* Posix 1003.1-1990 doesn't allow leap seconds, but some implementations
+* have them anyway, so allow them if localtime/gmtime does.
+*/
+	time_t
+tm2time(tm, localzone)
+	struct tm *tm;
+	int localzone;
+{
+	/* Cache the most recent t,tm pairs; 1 for gmtime, 1 for localtime.  */
+	static time_t t_cache[2];
+	static struct tm tm_cache[2];
+
+	time_t d, gt;
+	struct tm const *gtm;
+	/*
+	* The maximum number of iterations should be enough to handle any
+	* combinations of leap seconds, time zone rule changes, and solar time.
+	* 4 is probably enough; we use a bigger number just to be safe.
+	*/
+	int remaining_tries = 8;
+
+	/* Avoid subscript errors.  */
+	if (12 <= (unsigned)tm->tm_mon)
+	    return -1;
+
+	tm->tm_yday = month_yday[tm->tm_mon] + tm->tm_mday
+		-  (tm->tm_mon<2  ||  ! isleap(tm->tm_year + TM_YEAR_ORIGIN));
+
+	/* Make a first guess.  */
+	gt = t_cache[localzone];
+	gtm = gt ? &tm_cache[localzone] : time2tm(gt,localzone);
+
+	/* Repeatedly use the error from the guess to improve the guess.  */
+	while ((d = difftm(tm, gtm)) != 0) {
+		if (--remaining_tries == 0)
+			return -1;
+		gt += d;
+		gtm = time2tm(gt,localzone);
+	}
+	t_cache[localzone] = gt;
+	tm_cache[localzone] = *gtm;
+
+	/*
+	* Check that the guess actually matches;
+	* overflow can cause difftm to yield 0 even on differing times,
+	* or tm may have members out of range (e.g. bad leap seconds).
+	*/
+	if (   (tm->tm_year ^ gtm->tm_year)
+	    |  (tm->tm_mon  ^ gtm->tm_mon)
+	    |  (tm->tm_mday ^ gtm->tm_mday)
+	    |  (tm->tm_hour ^ gtm->tm_hour)
+	    |  (tm->tm_min  ^ gtm->tm_min)
+	    |  (tm->tm_sec  ^ gtm->tm_sec))
+		return -1;
+
+	tm->tm_wday = gtm->tm_wday;
+	return gt;
+}
+
+/*
+* Check *PT and convert it to time_t.
+* If it is incompletely specified, use DEFAULT_TIME to fill it out.
+* Use localtime if PT->zone is the special value TM_LOCAL_ZONE.
+* Yield -1 on failure.
+* ISO 8601 day-of-year and week numbers are not yet supported.
+*/
+	static time_t
+maketime(pt, default_time)
+	struct partime const *pt;
+	time_t default_time;
+{
+	int localzone, wday;
+	struct tm tm;
+	struct tm *tm0 = 0;
+	time_t r;
+
+	tm0 = 0; /* Keep gcc -Wall happy.  */
+	localzone = pt->zone==TM_LOCAL_ZONE;
+
+	tm = pt->tm;
+
+	if (TM_DEFINED(pt->ymodulus) || !TM_DEFINED(tm.tm_year)) {
+	    /* Get tm corresponding to current time.  */
+	    tm0 = time2tm(default_time, localzone);
+	    if (!localzone)
+		adjzone(tm0, pt->zone);
+	}
+
+	if (TM_DEFINED(pt->ymodulus))
+	    tm.tm_year +=
+		(tm0->tm_year + TM_YEAR_ORIGIN)/pt->ymodulus * pt->ymodulus;
+	else if (!TM_DEFINED(tm.tm_year)) {
+	    /* Set default year, month, day from current time.  */
+	    tm.tm_year = tm0->tm_year + TM_YEAR_ORIGIN;
+	    if (!TM_DEFINED(tm.tm_mon)) {
+		tm.tm_mon = tm0->tm_mon;
+		if (!TM_DEFINED(tm.tm_mday))
+		    tm.tm_mday = tm0->tm_mday;
+	    }
+	}
+
+	/* Convert from partime year (Gregorian) to Posix year.  */
+	tm.tm_year -= TM_YEAR_ORIGIN;
+
+	/* Set remaining default fields to be their minimum values.  */
+	if (!TM_DEFINED(tm.tm_mon)) tm.tm_mon = 0;
+	if (!TM_DEFINED(tm.tm_mday)) tm.tm_mday = 1;
+	if (!TM_DEFINED(tm.tm_hour)) tm.tm_hour = 0;
+	if (!TM_DEFINED(tm.tm_min)) tm.tm_min = 0;
+	if (!TM_DEFINED(tm.tm_sec)) tm.tm_sec = 0;
+
+	if (!localzone)
+	    adjzone(&tm, -pt->zone);
+	wday = tm.tm_wday;
+
+	/* Convert and fill in the rest of the tm.  */
+	r = tm2time(&tm, localzone);
+
+	/* Check weekday.  */
+	if (r != -1  &&  TM_DEFINED(wday)  &&  wday != tm.tm_wday)
+		return -1;
+
+	return r;
+}
+
+/* Parse a free-format date in SOURCE, yielding a Unix format time.  */
+	time_t
+str2time(source, default_time, default_zone)
+	char const *source;
+	time_t default_time;
+	long default_zone;
+{
+	struct partime pt;
+
+	if (*partime(source, &pt))
+	    return -1;
+	if (pt.zone == TM_UNDEFINED_ZONE)
+	    pt.zone = default_zone;
+	return maketime(&pt, default_time);
+}
+
+#if TEST
+#include <stdio.h>
+	int
+main(argc, argv) int argc; char **argv;
+{
+	time_t default_time = time((time_t *)0);
+	long default_zone = argv[1] ? atol(argv[1]) : 0;
+	char buf[1000];
+	while (fgets(buf, 1000, stdin)) {
+		time_t t = str2time(buf, default_time, default_zone);
+		printf("%s", asctime(gmtime(&t)));
+	}
+	return 0;
+}
+#endif