[FFmpeg-devel] [PATCH 1/3] avformat/avio: add resizeable field to AVIOContext

[Michael Niedermayer]

This indicates that its safe to use av_free/av_malloc on the IO context

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
---
 libavformat/avio.h    |    7 +++++++
 libavformat/aviobuf.c |    1 +
 libavformat/segment.c |    1 +
 libavformat/wtvdec.c  |    3 ++-
 4 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/libavformat/avio.h b/libavformat/avio.h
index 51913e3..73d1645 100644
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -196,6 +196,13 @@ typedef struct AVIOContext {
      * This field is internal to libavformat and access from outside is not allowed.
      */
     int orig_buffer_size;
+
+    /**
+     * The io buffer can be resized or freed with av_free / av_malloc.
+     * The user application does not keep a private copy of the buffer pointer
+     * which would become stale on such reallocation.
+     */
+    int resizeable;
 } AVIOContext;
 
 /* unbuffered I/O */
diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 7de59f1..b32ff9f 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -793,6 +793,7 @@ int ffio_fdopen(AVIOContext **s, URLContext *h)
         (*s)->read_seek  = (int64_t (*)(void *, int, int64_t, int))h->prot->url_read_seek;
     }
     (*s)->av_class = &ff_avio_class;
+    (*s)->resizeable = 1;
     return 0;
 }
 
diff --git a/libavformat/segment.c b/libavformat/segment.c
index 1162ea2..6504b46 100644
--- a/libavformat/segment.c
+++ b/libavformat/segment.c
@@ -511,6 +511,7 @@ static int open_null_ctx(AVIOContext **ctx)
         av_free(buf);
         return AVERROR(ENOMEM);
     }
+    (*ctx)->resizeable = 1;
     return 0;
 }
 
diff --git a/libavformat/wtvdec.c b/libavformat/wtvdec.c
index e226690..7b5477b 100644
--- a/libavformat/wtvdec.c
+++ b/libavformat/wtvdec.c
@@ -243,7 +243,8 @@ static AVIOContext * wtvfile_open_sector(int first_sector, uint64_t length, int
         av_freep(&buffer);
         av_freep(&wf->sectors);
         av_freep(&wf);
-    }
+    } else
+        pb->resizeable = 1;
     return pb;
 }
 
-- 
1.7.9.5