From: Lucas De Marchi <lucas.de.marchi@gmail.com>
Date: Tue, 12 Nov 2024 19:43:20 +0000 (-0600)
Subject: strbuf: Do not append '\0' if not needed
X-Git-Tag: v34~88
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cc2ba0b74a0b86b82181fbb1fa75d3ab953383cd;p=thirdparty%2Fkmod.git

strbuf: Do not append '\0' if not needed

Unconditionally appending '\0' is not a big problem, but that does
trigger the buffer to potentially be re-allocated. Avoid that by
checking the last char is not already NUL.

Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/239
---

diff --git a/shared/strbuf.c b/shared/strbuf.c
index 5a25976c..69d20db6 100644
--- a/shared/strbuf.c
+++ b/shared/strbuf.c
@@ -78,9 +78,11 @@ char *strbuf_steal(struct strbuf *buf)
 
 const char *strbuf_str(struct strbuf *buf)
 {
-	if (!strbuf_reserve_extra(buf, 1))
-		return NULL;
-	buf->bytes[buf->used] = '\0';
+	if (!buf->used || buf->bytes[buf->used - 1]) {
+		if (!strbuf_reserve_extra(buf, 1))
+			return NULL;
+		buf->bytes[buf->used] = '\0';
+	}
 	return buf->bytes;
 }