[FFmpeg-cvslog] lavu/dict: add AV_DICT_DEDUP

[rcombs]

ffmpeg | branch: master | rcombs <rcombs at rcombs.me> | Wed Aug 24 19:27:20 2022 -0500| [19e9a203b7b8e613840b055cdf68303a4fb84581] | committer: Michael Niedermayer

lavu/dict: add AV_DICT_DEDUP

This is useful when multiple metadata inputs may set the same value
(e.g. both a container-specific header and an ID3 tag).

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=19e9a203b7b8e613840b055cdf68303a4fb84581
---

 libavutil/dict.c | 11 +++++++++++
 libavutil/dict.h |  1 +
 2 files changed, 12 insertions(+)

diff --git a/libavutil/dict.c b/libavutil/dict.c
index a5fa2d3bfa..f7dcd07eeb 100644
--- a/libavutil/dict.c
+++ b/libavutil/dict.c
@@ -101,6 +101,17 @@ int av_dict_set(AVDictionary **pm, const char *key, const char *value,
     }
     if (!(flags & AV_DICT_MULTIKEY)) {
         tag = av_dict_get(m, key, NULL, flags);
+    } else if (flags & AV_DICT_DEDUP) {
+        while ((tag = av_dict_get(m, key, tag, flags))) {
+            if ((!value && !tag->value) ||
+                (value && tag->value && !strcmp(value, tag->value))) {
+                if (flags & AV_DICT_DONT_STRDUP_KEY)
+                    av_free((void*)key);
+                if (flags & AV_DICT_DONT_STRDUP_VAL)
+                    av_free((void*)value);
+                return 0;
+            }
+        }
     }
     if (flags & AV_DICT_DONT_STRDUP_KEY)
         copy_key = (void *)key;
diff --git a/libavutil/dict.h b/libavutil/dict.h
index 713c9e361a..654e7c35bd 100644
--- a/libavutil/dict.h
+++ b/libavutil/dict.h
@@ -82,6 +82,7 @@
 #define AV_DICT_APPEND         32   /**< If the entry already exists, append to it.  Note that no
                                          delimiter is added, the strings are simply concatenated. */
 #define AV_DICT_MULTIKEY       64   /**< Allow to store several equal keys in the dictionary */
+#define AV_DICT_DEDUP         128   /**< If inserting a value that already exists for a key, do nothing. Only relevant with AV_DICT_MULTIKEY. */
 /**
  * @}
  */