Index: int8.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/utils/adt/int8.c,v
retrieving revision 1.35
diff -u -3 -p -r1.35 int8.c
--- int8.c	2001/10/25 14:10:06	1.35
+++ int8.c	2001/11/22 08:48:09
@@ -28,6 +28,12 @@
 
 #define MAXINT8LEN		25
 
+#ifndef INT64_MAX
+#define INT64_MAX (0x7FFFFFFFFFFFFFFFLL)
+#endif
+#ifndef INT64_MIN
+#define INT64_MIN (-INT64_MAX-1)
+#endif
 #ifndef INT_MAX
 #define INT_MAX (0x7FFFFFFFL)
 #endif
@@ -62,6 +68,7 @@ int8in(PG_FUNCTION_ARGS)
 	char	   *ptr = str;
 	int64		tmp = 0;
 	int			sign = 1;
+	int64		limit;
 
 	/*
 	 * Do our own scan, rather than relying on sscanf which might be
@@ -75,18 +82,26 @@ int8in(PG_FUNCTION_ARGS)
 		ptr++;
 	if (!isdigit((unsigned char) *ptr)) /* require at least one digit */
 		elog(ERROR, "Bad int8 external representation \"%s\"", str);
+	if (sign < 0)
+		limit = INT64_MIN;
+	else
+		limit = -INT64_MAX;
 	while (*ptr && isdigit((unsigned char) *ptr))		/* process digits */
 	{
-		int64		newtmp = tmp * 10 + (*ptr++ - '0');
+		int			digit;
 
-		if ((newtmp / 10) != tmp)		/* overflow? */
+		if (tmp < -(INT64_MAX/10))		/* overflow? */
+			elog(ERROR, "int8 value out of range: \"%s\"", str);
+		digit = *ptr++ - '0';
+		tmp *= 10;
+		if (tmp < limit + digit)
 			elog(ERROR, "int8 value out of range: \"%s\"", str);
-		tmp = newtmp;
+		tmp -= digit;
 	}
 	if (*ptr)					/* trailing junk? */
 		elog(ERROR, "Bad int8 external representation \"%s\"", str);
 
-	result = (sign < 0) ? -tmp : tmp;
+	result = (sign < 0) ? tmp : -tmp;
 
 	PG_RETURN_INT64(result);
 }