[FFmpeg-devel] [PATCH v2 02/14] bytestream: Make get_bytes_left compatible with overread

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Sun Dec 15 00:19:14 EET 2019

bytestream2_get_bytes_left returns an unsigned int; as a result,
it returns big positive numbers if an overread already happened,
making it unsuitable for scenarios where one wants to allow this
in a controlled way (because the buffer is actually padded so that
no segfaults can happen). So change it to return an ordinary int.

Also, bytestream2_get_bytes_left_p has been modified in the same way.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
Implemented James' suggestion to return an int. I have not found a place
where this would pose a problem.

 libavcodec/bytestream.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/bytestream.h b/libavcodec/bytestream.h
index 7be7fc22fc..0516a6e3dc 100644
--- a/libavcodec/bytestream.h
+++ b/libavcodec/bytestream.h
@@ -151,12 +151,12 @@ static av_always_inline void bytestream2_init_writer(PutByteContext *p,
     p->eof          = 0;
-static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
+static av_always_inline int bytestream2_get_bytes_left(GetByteContext *g)
     return g->buffer_end - g->buffer;
-static av_always_inline unsigned int bytestream2_get_bytes_left_p(PutByteContext *p)
+static av_always_inline int bytestream2_get_bytes_left_p(PutByteContext *p)
     return p->buffer_end - p->buffer;

More information about the ffmpeg-devel mailing list