avformat: add ff_alloc_extradata() helper

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/libavformat/utils.c b/libavformat/utils.c
index 61405d7c97..6a7f58027c 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2678,6 +2678,26 @@ int av_find_stream_info(AVFormatContext *ic)
 }
 #endif
 
+int ff_alloc_extradata(AVCodecContext *avctx, int size)
+{
+    int ret;
+
+    if (size < 0 || size >= INT32_MAX - FF_INPUT_BUFFER_PADDING_SIZE) {
+        avctx->extradata_size = 0;
+        return AVERROR(EINVAL);
+    }
+    avctx->extradata = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
+    if (avctx->extradata) {
+        memset(avctx->extradata + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
+        avctx->extradata_size = size;
+        ret = 0;
+    } else {
+        avctx->extradata_size = 0;
+        ret = AVERROR(ENOMEM);
+    }
+    return ret;
+}
+
 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
 {
     int i, count, ret = 0, j;