X-Git-Url: http://git.csclub.uwaterloo.ca/?p=kopensolaris-gnu%2Fglibc.git;a=blobdiff_plain;f=time%2Fofftime.c;h=4e062df0d3a5a5929f0aabefc0090b3cb1e2bfe7;hp=13bc8805bca88f53294b7d8e6b581a76b96b8697;hb=0a0d9d20f716a8b48e2a2d2c6c243997d8b15543;hpb=56a6adbc81770d396272aee4cccf6042956661c5

diff --git a/time/offtime.c b/time/offtime.c
index 13bc8805bc..4e062df0d3 100644
--- a/time/offtime.c
+++ b/time/offtime.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991 Free Software Foundation, Inc.
+/* Copyright (C) 1991, 1993 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
@@ -19,32 +19,22 @@ Cambridge, MA 02139, USA.  */
 #include <ansidecl.h>
 #include <time.h>
 
-
-/* How many days are in each month.  */
-CONST 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 }
-  };
+/* Defined in mktime.c.  */
+extern CONST unsigned short int __mon_yday[2][13];
 
 #define	SECS_PER_HOUR	(60 * 60)
 #define	SECS_PER_DAY	(SECS_PER_HOUR * 24)
 
-/* Returns the `struct tm' representation of *T,
-   offset OFFSET seconds east of UCT.	*/
-struct tm *
-DEFUN(__offtime, (t, offset), CONST time_t *t AND long int offset)
+/* Compute the `struct tm' representation of *T,
+   offset OFFSET seconds east of UTC,
+   and store year, yday, mon, mday, wday, hour, min, sec into *TP.  */
+void
+DEFUN(__offtime, (t, offset, tp),
+      CONST time_t *t AND long int offset AND struct tm *tp)
 {
-  static struct tm tbuf;
-  register long int days, rem;
-  register int y;
+  register long int days, rem, y;
   register CONST unsigned short int *ip;
 
-  if (t == NULL)
-    return NULL;
-
   days = *t / SECS_PER_DAY;
   rem = *t % SECS_PER_DAY;
   rem += offset;
@@ -58,33 +48,35 @@ DEFUN(__offtime, (t, offset), CONST time_t *t AND long int offset)
       rem -= SECS_PER_DAY;
       ++days;
     }
-  tbuf.tm_hour = rem / SECS_PER_HOUR;
+  tp->tm_hour = rem / SECS_PER_HOUR;
   rem %= SECS_PER_HOUR;
-  tbuf.tm_min = rem / 60;
-  tbuf.tm_sec = rem % 60;
+  tp->tm_min = rem / 60;
+  tp->tm_sec = rem % 60;
   /* January 1, 1970 was a Thursday.  */
-  tbuf.tm_wday = (4 + days) % 7;
-  if (tbuf.tm_wday < 0)
-    tbuf.tm_wday += 7;
+  tp->tm_wday = (4 + days) % 7;
+  if (tp->tm_wday < 0)
+    tp->tm_wday += 7;
   y = 1970;
-  while (days >= (rem = __isleap(y) ? 366 : 365))
-    {
-      ++y;
-      days -= rem;
-    }
-  while (days < 0)
+
+# define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400)
+
+  while (days < 0 || days >= (__isleap (y) ? 366 : 365))
     {
-      --y;
-      days += __isleap(y) ? 366 : 365;
-    }
-  tbuf.tm_year = y - 1900;
-  tbuf.tm_yday = days;
-  ip = __mon_lengths[__isleap(y)];
-  for (y = 0; days >= ip[y]; ++y)
-    days -= ip[y];
-  tbuf.tm_mon = y;
-  tbuf.tm_mday = days + 1;
-  tbuf.tm_isdst = -1;
+      /* Guess a corrected year, assuming 365 days per year.  */
+      int yg = y + days / 365 - (days % 365 < 0);
 
-  return &tbuf;
+      /* Adjust DAYS and Y to match the guessed year.  */
+      days -= ((yg - y) * 365
+	       + LEAPS_THRU_END_OF (yg - 1)
+	       - LEAPS_THRU_END_OF (y - 1));
+      y = yg;
+    }
+  tp->tm_year = y - 1900;
+  tp->tm_yday = days;
+  ip = __mon_yday[__isleap(y)];
+  for (y = 11; days < ip[y]; --y)
+    continue;
+  days -= ip[y];
+  tp->tm_mon = y;
+  tp->tm_mday = days + 1;
 }