>From 7cf8459a82b03654b0886cf1ec0eb07169d6daa1 Mon Sep 17 00:00:00 2001
From: xiaozhuai <798047000@qq.com>
Date: Wed, 6 May 2026 12:33:13 +0800
Subject: [PATCH] avcodec/cbs: avoid empty type table

libavformat/cbs.c includes this file with a different set of CBS_*
macros. In configurations using --disable-everything, all coded
bitstream types may be disabled for that instance, leaving
cbs_type_table empty.

This triggers a zero-sized array warning with MSVC and may lead to an
internal compiler error with optimization enabled.

Add a NULL terminator and iterate until the terminator instead of using
FF_ARRAY_ELEMS(). The runtime behavior is unchanged.

The code currently permits building an instance of cbs.c with no enabled
coded bitstream types. In that case the generated table is empty. Make
the table explicitly NULL-terminated so this configuration is valid C
for compilers that reject or mishandle empty arrays.

Signed-off-by: xiaozhuai <798047000@qq.com>
---
 libavcodec/cbs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavcodec/cbs.c b/libavcodec/cbs.c
index 7ff0f89aa5..7357c0f9ac 100644
--- a/libavcodec/cbs.c
+++ b/libavcodec/cbs.c
@@ -61,6 +61,7 @@ static const CodedBitstreamType *const cbs_type_table[] = {
 #if CBS_VP9
     &CBS_FUNC(type_vp9),
 #endif
+    NULL
 };
 
 const enum AVCodecID CBS_FUNC(all_codec_ids)[] = {
@@ -105,7 +106,7 @@ av_cold int CBS_FUNC(init)(CodedBitstreamContext **ctx_ptr,
     int i;
 
     type = NULL;
-    for (i = 0; i < FF_ARRAY_ELEMS(cbs_type_table); i++) {
+    for (i = 0; cbs_type_table[i]; i++) {
         if (cbs_type_table[i]->codec_id == codec_id) {
             type = cbs_type_table[i];
             break;
-- 
2.54.0