Use psprintf to simplify gtsvectorout()

hlinnaka · hlinnaka · commit 3ab2668d4847 · 2024-08-06T23:05:25.000+03:00
The buffer allocation was correct, but looked archaic and scary: - It was weird to calculate the buffer size before determining which format string was used. With the same effort, we could've used the right-sized buffer for each branch. - Commit aa0d350 added one more possible return string ("all true bits"), but didn't adjust the code at the top of the function to calculate the returned string's max size. It was not a live bug, because the new string was smaller than the existing ones, but seemed wrong in principle. - Use of sprintf() is generally eyebrow-raising these days Switch to psprintf(). psprintf() allocates a larger buffer than what was allocated before, 128 bytes vs 80 bytes, which is acceptable as this code is not performance or space critical. Reviewed-by: Andres Freund Discussion: https://www.postgresql.org/message-id/54c29fb0-edf2-48ea-9814-44e918bbd6e8@iki.fi
diff --git a/src/backend/utils/adt/tsgistidx.c b/src/backend/utils/adt/tsgistidx.c
@@ -96,34 +96,25 @@ gtsvectorin(PG_FUNCTION_ARGS)
 	PG_RETURN_VOID();			/* keep compiler quiet */
 }
 
-#define SINGOUTSTR	"%d true bits, %d false bits"
-#define ARROUTSTR	"%d unique words"
-#define EXTRALEN	( 2*13 )
-
-static int	outbuf_maxlen = 0;
-
 Datum
 gtsvectorout(PG_FUNCTION_ARGS)
 {
 	SignTSVector *key = (SignTSVector *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
 	char	   *outbuf;
 
-	if (outbuf_maxlen == 0)
-		outbuf_maxlen = 2 * EXTRALEN + Max(strlen(SINGOUTSTR), strlen(ARROUTSTR)) + 1;
-	outbuf = palloc(outbuf_maxlen);
-
 	if (ISARRKEY(key))
-		sprintf(outbuf, ARROUTSTR, (int) ARRNELEM(key));
+		outbuf = psprintf("%d unique words", (int) ARRNELEM(key));
 	else
 	{
 		if (ISALLTRUE(key))
-			sprintf(outbuf, "all true bits");
+			outbuf = pstrdup("all true bits");
 		else
 		{
 			int			siglen = GETSIGLEN(key);
 			int			cnttrue = sizebitvec(GETSIGN(key), siglen);
 
-			sprintf(outbuf, SINGOUTSTR, cnttrue, (int) SIGLENBIT(siglen) - cnttrue);
+			outbuf = psprintf("%d true bits, %d false bits",
+							  cnttrue, (int) SIGLENBIT(siglen) - cnttrue);
 		}
 	}
 
