[FFmpeg-devel] [PATCH 1/6 v2] avutil/frame: add a flag to not create duplicate entries in a side data array

[James Almer]

Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavutil/frame.c | 14 ++++++++++++++
 libavutil/frame.h | 28 ++++++++++++++++++++--------
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/libavutil/frame.c b/libavutil/frame.c
index d7a32cdc92..a780e62fd0 100644
--- a/libavutil/frame.c
+++ b/libavutil/frame.c
@@ -774,6 +774,13 @@ AVFrameSideData *av_frame_side_data_new(AVFrameSideData ***sd, int *nb_sd,
 
     if (flags & AV_FRAME_SIDE_DATA_FLAG_UNIQUE)
         remove_side_data(sd, nb_sd, type);
+    if (flags & AV_FRAME_SIDE_DATA_FLAG_DONT_APPEND) {
+        for (int i = 0; i < *nb_sd; i++) {
+            AVFrameSideData *entry = ((*sd)[i]);
+            if (entry->type == type)
+                return entry;
+        }
+    }
 
     ret = add_side_data_from_buf(sd, nb_sd, type, buf);
     if (!ret)
@@ -798,6 +805,13 @@ int av_frame_side_data_clone(AVFrameSideData ***sd, int *nb_sd,
 
     if (flags & AV_FRAME_SIDE_DATA_FLAG_UNIQUE)
         remove_side_data(sd, nb_sd, src->type);
+    if (flags & AV_FRAME_SIDE_DATA_FLAG_DONT_APPEND) {
+        for (int i = 0; i < *nb_sd; i++) {
+            AVFrameSideData *entry = ((*sd)[i]);
+            if (entry->type == src->type)
+                return 0;
+        }
+    }
 
     sd_dst = add_side_data_from_buf(sd, nb_sd, src->type, buf);
     if (!sd_dst) {
diff --git a/libavutil/frame.h b/libavutil/frame.h
index 8aa05ec127..7cc55a455e 100644
--- a/libavutil/frame.h
+++ b/libavutil/frame.h
@@ -1003,7 +1003,14 @@ const char *av_frame_side_data_name(enum AVFrameSideDataType type);
  */
 void av_frame_side_data_free(AVFrameSideData ***sd, int *nb_sd);
 
+/**
+ * Remove existing entries before adding new ones.
+ */
 #define AV_FRAME_SIDE_DATA_FLAG_UNIQUE (1 << 0)
+/**
+ * Don't add a new entry if another of the same type exists.
+ */
+#define AV_FRAME_SIDE_DATA_FLAG_DONT_APPEND (1 << 1)
 
 /**
  * Add new side data entry to an array.
@@ -1016,10 +1023,12 @@ void av_frame_side_data_free(AVFrameSideData ***sd, int *nb_sd);
  * @param size  size of the side data
  * @param flags Some combination of AV_FRAME_SIDE_DATA_FLAG_* flags, or 0.
  *
- * @return newly added side data on success, NULL on error. In case of
- *         AV_FRAME_SIDE_DATA_FLAG_UNIQUE being set, entries of matching
- *         AVFrameSideDataType will be removed before the addition is
- *         attempted.
+ * @return newly added side data on success, NULL on error.
+ * @note In case of AV_FRAME_SIDE_DATA_FLAG_UNIQUE being set, entries of
+ *       matching AVFrameSideDataType will be removed before the addition
+ *       is attempted.
+ * @note In case of AV_FRAME_SIDE_DATA_FLAG_DONT_APPEND being set, if an
+ *       entry of the same type already exists, it will be returned instead.
  */
 AVFrameSideData *av_frame_side_data_new(AVFrameSideData ***sd, int *nb_sd,
                                         enum AVFrameSideDataType type,
@@ -1037,10 +1046,13 @@ AVFrameSideData *av_frame_side_data_new(AVFrameSideData ***sd, int *nb_sd,
  *              for the buffer.
  * @param flags Some combination of AV_FRAME_SIDE_DATA_FLAG_* flags, or 0.
  *
- * @return negative error code on failure, >=0 on success. In case of
- *         AV_FRAME_SIDE_DATA_FLAG_UNIQUE being set, entries of matching
- *         AVFrameSideDataType will be removed before the addition is
- *         attempted.
+ * @return negative error code on failure, >=0 on success.
+ * @note In case of AV_FRAME_SIDE_DATA_FLAG_UNIQUE being set, entries of
+ *       matching AVFrameSideDataType will be removed before the addition
+ *       is attempted.
+ * @note In case of AV_FRAME_SIDE_DATA_FLAG_DONT_APPEND being set, if an
+ *       entry of the same type as the one from src already exists, this
+ *       function will be a no-op.
  */
 int av_frame_side_data_clone(AVFrameSideData ***sd, int *nb_sd,
                              const AVFrameSideData *src, unsigned int flags);
-- 
2.44.0