lavf: add a convenience function for adding side data to a stream

libavformat/utils.c

@@ -3113,3 +3113,40 @@ uint8_t *av_stream_get_side_data(AVStream *st, enum AVPacketSideDataType type,
     }
     return NULL;
 }
+
+uint8_t *ff_stream_new_side_data(AVStream *st, enum AVPacketSideDataType type,
+                                 int size)
+{
+    AVPacketSideData *sd, *tmp;
+    int i;
+    uint8_t *data = av_malloc(size);
+
+    if (!data)
+        return NULL;
+
+    for (i = 0; i < st->nb_side_data; i++) {
+        sd = &st->side_data[i];
+
+        if (sd->type == type) {
+            av_freep(&sd->data);
+            sd->data = data;
+            sd->size = size;
+            return sd->data;
+        }
+    }
+
+    tmp = av_realloc_array(st->side_data, st->nb_side_data + 1, sizeof(*tmp));
+    if (!tmp) {
+        av_freep(&data);
+        return NULL;
+    }
+
+    st->side_data = tmp;
+    st->nb_side_data++;
+
+    sd = &st->side_data[st->nb_side_data - 1];
+    sd->type = type;
+    sd->data = data;
+    sd->size = size;
+    return data;
+}