avformat/aviobuf: check if requested seekback buffer is already read

Existing code did not check if the requested seekback buffer is
already read entirely. In this case, nothing has to be done to guarantee
seekback.

Signed-off-by: Marton Balint <cus@passwd.hu>

diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 96754253497609c139a89960a560ce414346e58e..d94be478acc8d6fd5d2f5c8fbfe0f4eb09cd8146 100644 (file)
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -999,6 +999,9 @@ int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
     int filled = s->buf_end - s->buffer;
     ptrdiff_t checksum_ptr_offset = s->checksum_ptr ? s->checksum_ptr - s->buffer : -1;
 
+    if (buf_size <= s->buf_end - s->buf_ptr)
+        return 0;
+
     buf_size += s->buf_ptr - s->buffer + max_buffer_size;
 
     if (buf_size < filled || s->seekable || !s->read_packet)