avformat/avio: add avio_protocol_get_class

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Suggested-by: Hendrik Leppkes <h.leppkes@gmail.com>
Suggested-by: Nicolas George <george@nsup.org>
Signed-off-by: Steven Liu <lq@chinaffmpeg.org>

doc/APIchanges

@@ -15,6 +15,9 @@ libavutil:     2017-10-21
 
 API changes, most recent first:
 
+2020-01-30 - xxxxxxxxxx - lavf 58.37.100 - avio.h
+  Add avio_protocol_get_class().
+
 2020-01-15 - xxxxxxxxxx - lavc 58.66.100 - avcodec.h
   Add AV_PKT_DATA_PRFT and AVProducerReferenceTime.
 

libavformat/avio.h

@@ -807,6 +807,13 @@ int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
  */
 const char *avio_enum_protocols(void **opaque, int output);
 
+/**
+ * Get AVClass by names of available protocols.
+ *
+ * @return A AVClass of input protocol name or NULL
+ */
+const AVClass *avio_protocol_get_class(const char *name);
+
 /**
  * Pause and resume playing - only meaningful if using a network streaming
  * protocol (e.g. MMS).

libavformat/protocols.c

@@ -107,6 +107,16 @@ const char *avio_enum_protocols(void **opaque, int output)
     return avio_enum_protocols(opaque, output);
 }
 
+const AVClass *avio_protocol_get_class(const char *name)
+{
+    int i = 0;
+    for (i = 0; url_protocols[i]; i++) {
+        if (!strcmp(url_protocols[i]->name, name))
+            return url_protocols[i]->priv_data_class;
+    }
+    return NULL;
+}
+
 const URLProtocol **ffurl_get_protocols(const char *whitelist,
                                         const char *blacklist)
 {

libavformat/version.h

@@ -32,7 +32,7 @@
 // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  58
-#define LIBAVFORMAT_VERSION_MINOR  36
+#define LIBAVFORMAT_VERSION_MINOR  37
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \