avformat/avio: Avoid function pointer casts

It is undefined behaviour to use a different type for a call
than the actual type of the function.

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

libavformat/avio.c

@@ -450,9 +450,8 @@ int ffio_fdopen(AVIOContext **s, URLContext *h)
     (*s)->max_packet_size = max_packet_size;
     (*s)->min_packet_size = h->min_packet_size;
     if(h->prot) {
-        (*s)->read_pause = (int (*)(void *, int))h->prot->url_read_pause;
-        (*s)->read_seek  =
-            (int64_t (*)(void *, int, int64_t, int))h->prot->url_read_seek;
+        (*s)->read_pause = h->prot->url_read_pause;
+        (*s)->read_seek  = h->prot->url_read_seek;
 
         if (h->prot->url_read_seek)
             (*s)->seekable |= AVIO_SEEKABLE_TIME;

libavformat/librtmp.c

@@ -220,8 +220,9 @@ static int rtmp_read(URLContext *s, uint8_t *buf, int size)
     return ret;
 }
 
-static int rtmp_read_pause(URLContext *s, int pause)
+static int rtmp_read_pause(void *opaque, int pause)
 {
+    URLContext *s = opaque;
     LibRTMPContext *ctx = s->priv_data;
     RTMP *r = &ctx->rtmp;
 
@@ -230,9 +231,10 @@ static int rtmp_read_pause(URLContext *s, int pause)
     return 0;
 }
 
-static int64_t rtmp_read_seek(URLContext *s, int stream_index,
+static int64_t rtmp_read_seek(void *opaque, int stream_index,
                               int64_t timestamp, int flags)
 {
+    URLContext *s = opaque;
     LibRTMPContext *ctx = s->priv_data;
     RTMP *r = &ctx->rtmp;
 

libavformat/mmsh.c

@@ -371,9 +371,10 @@ static int mmsh_read(URLContext *h, uint8_t *buf, int size)
     return res;
 }
 
-static int64_t mmsh_read_seek(URLContext *h, int stream_index,
+static int64_t mmsh_read_seek(void *opaque, int stream_index,
                         int64_t timestamp, int flags)
 {
+    URLContext *h = opaque;
     MMSHContext *mmsh_old = h->priv_data;
     MMSHContext *mmsh     = av_mallocz(sizeof(*mmsh));
     int ret;

libavformat/rtmpproto.c

@@ -2952,9 +2952,10 @@ static int rtmp_read(URLContext *s, uint8_t *buf, int size)
     return orig_size;
 }
 
-static int64_t rtmp_seek(URLContext *s, int stream_index, int64_t timestamp,
+static int64_t rtmp_seek(void *opaque, int stream_index, int64_t timestamp,
                          int flags)
 {
+    URLContext *s = opaque;
     RTMPContext *rt = s->priv_data;
     int ret;
     av_log(s, AV_LOG_DEBUG,
@@ -2972,8 +2973,9 @@ static int64_t rtmp_seek(URLContext *s, int stream_index, int64_t timestamp,
     return timestamp;
 }
 
-static int rtmp_pause(URLContext *s, int pause)
+static int rtmp_pause(void *opaque, int pause)
 {
+    URLContext *s = opaque;
     RTMPContext *rt = s->priv_data;
     int ret;
     av_log(s, AV_LOG_DEBUG, "Pause at timestamp %d\n",

libavformat/url.h

@@ -76,8 +76,8 @@ typedef struct URLProtocol {
     int     (*url_write)(URLContext *h, const unsigned char *buf, int size);
     int64_t (*url_seek)( URLContext *h, int64_t pos, int whence);
     int     (*url_close)(URLContext *h);
-    int (*url_read_pause)(URLContext *h, int pause);
-    int64_t (*url_read_seek)(URLContext *h, int stream_index,
+    int (*url_read_pause)(void *urlcontext, int pause);
+    int64_t (*url_read_seek)(void *urlcontext, int stream_index,
                              int64_t timestamp, int flags);
     int (*url_get_file_handle)(URLContext *h);
     int (*url_get_multi_file_handle)(URLContext *h, int **handles,