--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/mktime.c	Sun Nov 01 05:44:30 1992 +0000
@@ -0,0 +1,224 @@
+/* Copyright (C) 1991 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <sys/types.h>
+#include <errno.h>
+#ifndef STDC_HEADERS
+extern int errno;
+#endif
+#ifdef TM_IN_SYS_TIME
+#include <sys/time.h>
+#else
+#include <time.h>
+#endif
+#ifdef HAVE_LIMITS_H
+#include <limits.h>
+#else
+#define	LONG_MAX (~(1 << (sizeof (long) * 8 - 1)))
+#define LONG_MIN (-LONG_MAX - 1)
+#define	INT_MAX (~(1 << (sizeof (int) * 8 - 1)))
+#define INT_MIN (-INT_MAX - 1)
+#endif
+
+#ifndef NULL
+#define NULL 0
+#endif
+
+#ifndef __isleap
+/* Nonzero if YEAR is a leap year (every 4 years,
+   except every 100th isn't, and every 1000th is).  */
+#define	__isleap(year)	\
+  ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 1000 == 0))
+#endif
+
+/* How many days are in each month.  */
+static unsigned short int __mon_lengths[2][12] =
+{
+  /* Normal years.  */
+  { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
+  /* Leap years.  */
+  { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
+};
+
+#define	invalid()	return (time_t) -1
+
+/* Return the `time_t' representation of TP and normalizes TP.
+   Return (time_t) -1 if TP is not representable as a `time_t'.
+   Note that 31 Dec 1969 23:59:59 is not representable
+   because it is represented as (time_t) -1.  */
+time_t
+mktime(tp)
+register struct tm *tp;
+{
+  static struct tm min, max;
+  static char init = 0;
+
+  register time_t result;
+  register time_t t;
+  register int i;
+  register unsigned short *l;
+  register struct tm *new;
+  time_t end;
+
+  if (tp == NULL)
+    {
+      errno = EINVAL;
+      invalid();
+    }
+
+  if (!init)
+    {
+      init = 1;
+      end = (time_t) LONG_MIN;
+      new = gmtime(&end);
+      if (new != NULL)
+	min = *new;
+      else
+	min.tm_sec = min.tm_min = min.tm_hour =
+	  min.tm_mday = min.tm_mon = min.tm_year = INT_MIN;
+
+      end = (time_t) LONG_MAX;
+      new = gmtime(&end);
+      if (new != NULL)
+	max = *new;
+      else
+	max.tm_sec = max.tm_min = max.tm_hour =
+	  max.tm_mday = max.tm_mon = max.tm_year = INT_MAX;
+    }
+
+  /* Make all the elements of TP that we pay attention to
+     be within the ranges of reasonable values for those things.  */
+#define	normalize(elt, min, max, nextelt) \
+  while (tp->elt < min)							      \
+    {									      \
+      --tp->nextelt;							      \
+      tp->elt += max + 1;						      \
+    }									      \
+  while (tp->elt > max)							      \
+    {									      \
+      ++tp->nextelt;							      \
+      tp->elt -= max + 1;						      \
+    }
+
+  normalize (tm_sec, 0, 59, tm_min);
+  normalize (tm_min, 0, 59, tm_hour);
+  normalize (tm_hour, 0, 24, tm_mday);
+
+  /* Normalize the month first so we can use
+     it to figure the range for the day.  */
+  normalize (tm_mon, 0, 11, tm_year);
+  normalize (tm_mday, 1, __mon_lengths[__isleap (tp->tm_year)][tp->tm_mon],
+	     tm_mon);
+
+  /* Normalize the month again, since normalizing
+     the day may have pushed it out of range.  */
+  normalize (tm_mon, 0, 11, tm_year);
+
+  /* Normalize the day again, because normalizing
+     the month may have changed the range.  */
+  normalize (tm_mday, 1, __mon_lengths[__isleap (tp->tm_year)][tp->tm_mon],
+	     tm_mon);
+
+  /* Check for out-of-range values.  */
+#define	lowhigh(field, minmax, cmp)	(tp->field cmp minmax.field)
+#define	low(field)			lowhigh(field, min, <)
+#define	high(field)			lowhigh(field, max, >)
+#define	oor(field)			(low(field) || high(field))
+#define	lowbound(field)			(tp->field == min.field)
+#define	highbound(field)		(tp->field == max.field)
+  if (oor(tm_year))
+    invalid();
+  else if (lowbound(tm_year))
+    {
+      if (low(tm_mon))
+	invalid();
+      else if (lowbound(tm_mon))
+	{
+	  if (low(tm_mday))
+	    invalid();
+	  else if (lowbound(tm_mday))
+	    {
+	      if (low(tm_hour))
+		invalid();
+	      else if (lowbound(tm_hour))
+		{
+		  if (low(tm_min))
+		    invalid();
+		  else if (lowbound(tm_min))
+		    {
+		      if (low(tm_sec))
+			invalid();
+		    }
+		}
+	    }
+	}
+    }
+  else if (highbound(tm_year))
+    {
+      if (high(tm_mon))
+	invalid();
+      else if (highbound(tm_mon))
+	{
+	  if (high(tm_mday))
+	    invalid();
+	  else if (highbound(tm_mday))
+	    {
+	      if (high(tm_hour))
+		invalid();
+	      else if (highbound(tm_hour))
+		{
+		  if (high(tm_min))
+		    invalid();
+		  else if (highbound(tm_min))
+		    {
+		      if (high(tm_sec))
+			invalid();
+		    }
+		}
+	    }
+	}
+    }
+
+  t = 0;
+  for (i = 1970; i > 1900 + tp->tm_year; --i)
+    t -= __isleap(i) ? 366 : 365;
+  for (i = 1970; i < 1900 + tp->tm_year; ++i)
+    t += __isleap(i) ? 366 : 365;
+  l = __mon_lengths[__isleap(1900 + tp->tm_year)];
+  for (i = 0; i < tp->tm_mon; ++i)
+    t += l[i];
+  t += tp->tm_mday - 1;
+  result = ((t * 60 * 60 * 24) +
+	    (tp->tm_hour * 60 * 60) +
+	    (tp->tm_min * 60) +
+	    tp->tm_sec);
+
+  end = result;
+#if 0				/* This code breaks it, on SunOS anyway. */
+  if (tp->tm_isdst < 0)
+    new = localtime(&end);
+  else
+#endif
+    new = gmtime(&end);
+  if (new == NULL)
+    invalid();
+  new->tm_isdst = tp->tm_isdst;
+  *tp = *new;
+
+  return result;
+}