From afd9e3ed3ff9ead46a233d11b45780b7585b00a3 Mon Sep 17 00:00:00 2001
From: judeng <abc3844@126.com>
Date: Sun, 22 Jan 2023 15:16:17 +0800
Subject: [PATCH] Optimize the performance of sdscatrepr in printable
 characters (#11725)

sdscatrepr is not the hot path in redis, but it's still useful to have make it less wasteful.
---
 src/sds.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/sds.c b/src/sds.c
index 4e934d7ad..e0e726dbb 100644
--- a/src/sds.c
+++ b/src/sds.c
@@ -997,6 +997,7 @@ void sdsfreesplitres(sds *tokens, int count) {
  * After the call, the modified sds string is no longer valid and all the
  * references must be substituted with the new pointer returned by the call. */
 sds sdscatrepr(sds s, const char *p, size_t len) {
+    s = sdsMakeRoomFor(s, len + 2);
     s = sdscatlen(s,"\"",1);
     while(len--) {
         switch(*p) {
@@ -1011,7 +1012,7 @@ sds sdscatrepr(sds s, const char *p, size_t len) {
         case '\b': s = sdscatlen(s,"\\b",2); break;
         default:
             if (isprint(*p))
-                s = sdscatprintf(s,"%c",*p);
+                s = sdscatlen(s, p, 1);
             else
                 s = sdscatprintf(s,"\\x%02x",(unsigned char)*p);
             break;