Change comparisons of tm->tm_isdst from "nonzero" to "greater than zero".

 Not sure why some were this way, and others were already correct, but it
 seems to have been like this for several years.
This caused problems on a few damaged platforms like AIX and IRIX which do
 not support DST calculations for years before 1970.
Thanks to Andreas Zeugswetter <ZeugswetterA@wien.spardat.at> for finding
 the problem.

1 files changed, 44 insertions, 39 deletions

diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 1426088e62b..659cc584ba3 100644
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/datetime.c,v 1.57 2000/12/03 20:45:35 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/datetime.c,v 1.58 2001/01/17 16:46:56 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2229,21 +2229,27 @@ EncodeTimeSpan(struct tm * tm, double fsec, int style, char *str)
 				sprintf(cp, "%d year%s",
 						tm->tm_year, ((tm->tm_year != 1) ? "s" : ""));
 				cp += strlen(cp);
+				is_before = (tm->tm_year < 0);
 				is_nonzero = TRUE;
 			}
 
 			if (tm->tm_mon != 0)
 			{
-				sprintf(cp, "%s%d mon%s", (is_nonzero ? " " : ""),
+				sprintf(cp, "%s%s%d mon%s", (is_nonzero ? " " : ""),
+						((is_before && (tm->tm_mon > 0)) ? "+" : ""),
 						tm->tm_mon, ((tm->tm_mon != 1) ? "s" : ""));
 				cp += strlen(cp);
+				is_before = (tm->tm_mon < 0);
 				is_nonzero = TRUE;
 			}
 
 			if (tm->tm_mday != 0)
 			{
-				sprintf(cp, "%s%d", (is_nonzero ? " " : ""), tm->tm_mday);
+				sprintf(cp, "%s%s%d day%s", (is_nonzero ? " " : ""),
+						((is_before && (tm->tm_mday > 0)) ? "+" : ""),
+						tm->tm_mday, ((tm->tm_mday != 1) ? "s" : ""));
 				cp += strlen(cp);
+				is_before = (tm->tm_mday < 0);
 				is_nonzero = TRUE;
 			}
 			{
@@ -2251,7 +2257,7 @@ EncodeTimeSpan(struct tm * tm, double fsec, int style, char *str)
 							 || (tm->tm_sec < 0) || (fsec < 0));
 
 				sprintf(cp, "%s%s%02d:%02d", (is_nonzero ? " " : ""),
-						(minus ? "-" : "+"),
+						(minus ? "-" : (is_nonzero ? "+" : "")),
 						abs(tm->tm_hour), abs(tm->tm_min));
 				cp += strlen(cp);
 				/* Mark as "non-zero" since the fields are now filled in */
@@ -2283,59 +2289,59 @@ EncodeTimeSpan(struct tm * tm, double fsec, int style, char *str)
 
 			if (tm->tm_year != 0)
 			{
-				is_before = (tm->tm_year < 0);
-				if (is_before)
-					tm->tm_year = -tm->tm_year;
-				sprintf(cp, "%d year%s",
-						tm->tm_year, ((tm->tm_year != 1) ? "s" : ""));
+				int year = ((tm->tm_year < 0) ? -(tm->tm_year) : tm->tm_year);
+
+				sprintf(cp, "%d year%s", year,
+						((year != 1) ? "s" : ""));
 				cp += strlen(cp);
+				is_before = (tm->tm_year < 0);
 				is_nonzero = TRUE;
 			}
 
 			if (tm->tm_mon != 0)
 			{
+				int mon = ((is_before && (tm->tm_mon > 0)) ? -(tm->tm_mon) : tm->tm_mon);
+
+				sprintf(cp, "%s%d mon%s", (is_nonzero ? " " : ""), mon,
+						((mon != 1) ? "s" : ""));
+				cp += strlen(cp);
 				if (! is_nonzero)
 					is_before = (tm->tm_mon < 0);
-				if (is_before)
-					tm->tm_mon = -tm->tm_mon;
-				sprintf(cp, "%s%d mon%s", (is_nonzero ? " " : ""),
-						tm->tm_mon, ((tm->tm_mon != 1) ? "s" : ""));
-				cp += strlen(cp);
 				is_nonzero = TRUE;
 			}
 
 			if (tm->tm_mday != 0)
 			{
+				int day = ((is_before && (tm->tm_mday > 0)) ? -(tm->tm_mday) : tm->tm_mday);
+
+				sprintf(cp, "%s%d day%s", (is_nonzero ? " " : ""), day,
+						((day != 1) ? "s" : ""));
+				cp += strlen(cp);
 				if (! is_nonzero)
 					is_before = (tm->tm_mday < 0);
-				if (is_before)
-					tm->tm_mday = -tm->tm_mday;
-				sprintf(cp, "%s%d day%s", (is_nonzero ? " " : ""),
-				 tm->tm_mday, ((tm->tm_mday != 1) ? "s" : ""));
-				cp += strlen(cp);
 				is_nonzero = TRUE;
 			}
 			if (tm->tm_hour != 0)
 			{
+				int hour = ((is_before && (tm->tm_hour > 0)) ? -(tm->tm_hour) : tm->tm_hour);
+
+				sprintf(cp, "%s%d hour%s", (is_nonzero ? " " : ""), hour,
+						((hour != 1) ? "s" : ""));
+				cp += strlen(cp);
 				if (! is_nonzero)
 					is_before = (tm->tm_hour < 0);
-				if (is_before)
-					tm->tm_hour = -tm->tm_hour;
-				sprintf(cp, "%s%d hour%s", (is_nonzero ? " " : ""),
-				 tm->tm_hour, ((tm->tm_hour != 1) ? "s" : ""));
-				cp += strlen(cp);
 				is_nonzero = TRUE;
 			}
 
 			if (tm->tm_min != 0)
 			{
+				int min = ((is_before && (tm->tm_min > 0)) ? -(tm->tm_min) : tm->tm_min);
+
+				sprintf(cp, "%s%d min%s", (is_nonzero ? " " : ""), min,
+						((min != 1) ? "s" : ""));
+				cp += strlen(cp);
 				if (! is_nonzero)
 					is_before = (tm->tm_min < 0);
-				if (is_before)
-					tm->tm_min = -tm->tm_min;
-				sprintf(cp, "%s%d min%s", (is_nonzero ? " " : ""),
-				   tm->tm_min, ((tm->tm_min != 1) ? "s" : ""));
-				cp += strlen(cp);
 				is_nonzero = TRUE;
 			}
 
@@ -2343,25 +2349,24 @@ EncodeTimeSpan(struct tm * tm, double fsec, int style, char *str)
 			if (fsec != 0)
 			{
 				fsec += tm->tm_sec;
+				sprintf(cp, "%s%.2f secs", (is_nonzero ? " " : ""),
+						((is_before && (fsec > 0)) ? -(fsec) : fsec));
+				cp += strlen(cp);
 				if (! is_nonzero)
 					is_before = (fsec < 0);
-				if (is_before)
-					fsec = -fsec;
-				sprintf(cp, "%s%.2f secs", (is_nonzero ? " " : ""), fsec);
-				cp += strlen(cp);
 				is_nonzero = TRUE;
 
 				/* otherwise, integer seconds only? */
 			}
 			else if (tm->tm_sec != 0)
 			{
+				int sec = ((is_before && (tm->tm_sec > 0)) ? -(tm->tm_sec) : tm->tm_sec);
+
+				sprintf(cp, "%s%d sec%s", (is_nonzero ? " " : ""), sec,
+						((sec != 1) ? "s" : ""));
+				cp += strlen(cp);
 				if (! is_nonzero)
 					is_before = (tm->tm_sec < 0);
-				if (is_before)
-					tm->tm_sec = -tm->tm_sec;
-				sprintf(cp, "%s%d sec%s", (is_nonzero ? " " : ""),
-				   tm->tm_sec, ((tm->tm_sec != 1) ? "s" : ""));
-				cp += strlen(cp);
 				is_nonzero = TRUE;
 			}
 			break;
@@ -2374,7 +2379,7 @@ EncodeTimeSpan(struct tm * tm, double fsec, int style, char *str)
 		cp += strlen(cp);
 	}
 
-	if (is_before)
+	if (is_before && (style == USE_POSTGRES_DATES))
 	{
 		strcat(cp, " ago");
 		cp += strlen(cp);