avformat: Avoid allocation for AVFormatInternal

Do this by allocating AVFormatContext together with the data that is
currently in AVFormatInternal; or rather: Put AVFormatContext at the
beginning of a new structure called FFFormatContext (which encompasses
more than just the internal fields and is a proper context in its own
right, hence the name) and remove AVFormatInternal altogether.

The biggest simplifications occured in avformat_alloc_context(), where
one can now simply call avformat_free_context() in case of errors.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 16 insertions, 29 deletions

diff --git a/libavformat/options.c b/libavformat/options.c
index dccb6faa73..753aa9b8dc 100644
--- a/libavformat/options.c
+++ b/libavformat/options.c
@@ -151,46 +151,33 @@ static void io_close_default(AVFormatContext *s, AVIOContext *pb)
     avio_close(pb);
 }
 
-static void avformat_get_context_defaults(AVFormatContext *s)
+AVFormatContext *avformat_alloc_context(void)
 {
-    memset(s, 0, sizeof(AVFormatContext));
+    FFFormatContext *const si = av_mallocz(sizeof(*si));
+    AVFormatContext *s;
 
-    s->av_class = &av_format_context_class;
+    if (!si)
+        return NULL;
 
+    s = &si->pub;
+    s->av_class = &av_format_context_class;
     s->io_open  = io_open_default;
     s->io_close = io_close_default;
 
     av_opt_set_defaults(s);
-}
 
-AVFormatContext *avformat_alloc_context(void)
-{
-    AVFormatContext *ic;
-    AVFormatInternal *internal;
-    ic = av_malloc(sizeof(AVFormatContext));
-    if (!ic) return ic;
-
-    internal = av_mallocz(sizeof(*internal));
-    if (!internal) {
-        av_free(ic);
+    si->pkt = av_packet_alloc();
+    si->parse_pkt = av_packet_alloc();
+    if (!si->pkt || !si->parse_pkt) {
+        avformat_free_context(s);
         return NULL;
     }
-    internal->pkt = av_packet_alloc();
-    internal->parse_pkt = av_packet_alloc();
-    if (!internal->pkt || !internal->parse_pkt) {
-        av_packet_free(&internal->pkt);
-        av_packet_free(&internal->parse_pkt);
-        av_free(internal);
-        av_free(ic);
-        return NULL;
-    }
-    avformat_get_context_defaults(ic);
-    ic->internal = internal;
-    ic->internal->offset = AV_NOPTS_VALUE;
-    ic->internal->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;
-    ic->internal->shortest_end = AV_NOPTS_VALUE;
 
-    return ic;
+    si->offset = AV_NOPTS_VALUE;
+    si->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;
+    si->shortest_end = AV_NOPTS_VALUE;
+
+    return s;
 }
 
 enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx)