Change avf_sdp_create() to get a pre-allocated buffer as input, and to

return an integer (0 if the SDP has been succesfully created, < 0 in case
of error)

Originally committed as revision 9947 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avformat.h

@@ -842,12 +842,13 @@ int av_filename_number_test(const char *filename);
  *           multiple AVStreams (one AVStream per RTP stream). Otherwise,
  *           all the contexts in the array (an AVCodecContext per RTP stream)
  *           must contain only one AVStream
- * @param n_streams number of AVCodecContexts contained in ac
+ * @param n_files number of AVCodecContexts contained in ac
- * @return a pointer to the SDP (an array of chars which is allocated by
+ * @param buff buffer where the SDP will be stored (must be allocated by
- *         avf_sdp_create(), and must be freed by the caller), or NULL in
+ *             the caller
- *         case of failure.
+ * @param size the size of the buffer
+ * @return 0 if OK. AVERROR_xxx if error.
  */
-char *avf_sdp_create(AVFormatContext *ac[], int n_streams);
+int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size);
 
 #ifdef HAVE_AV_CONFIG_H
 

libavformat/sdp.c

@@ -169,19 +169,12 @@ static void sdp_write_media(char *buff, int size, AVCodecContext *c, const char
     sdp_media_attributes(buff, size, c, payload_type);
 }
 
-#define SDP_BUFFER_SIZE 2048
+int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size)
-char *avf_sdp_create(AVFormatContext *ac[], int n_files)
 {
-    char *buff;
     struct sdp_session_level s;
     int i, j, port, ttl;
     char dst[32];
 
-    buff = av_mallocz(SDP_BUFFER_SIZE);
-    if (buff == NULL) {
-        return NULL;
-    }
-
     memset(&s, 0, sizeof(struct sdp_session_level));
     s.user = "-";
     s.src_addr = "127.0.0.1";    /* FIXME: Properly set this */
@@ -196,7 +189,7 @@ char *avf_sdp_create(AVFormatContext *ac[], int n_files)
             s.ttl = ttl;
         }
     }
-    sdp_write_header(buff, SDP_BUFFER_SIZE, &s);
+    sdp_write_header(buff, size, &s);
 
     dst[0] = 0;
     for (i = 0; i < n_files; i++) {
@@ -204,21 +197,21 @@ char *avf_sdp_create(AVFormatContext *ac[], int n_files)
             port = get_address(dst, sizeof(dst), &ttl, ac[i]->filename);
         }
         for (j = 0; j < ac[i]->nb_streams; j++) {
-            sdp_write_media(buff, SDP_BUFFER_SIZE,
+            sdp_write_media(buff, size,
                                   ac[i]->streams[j]->codec, dst[0] ? dst : NULL,
                                   (port > 0) ? port + j * 2 : 0, ttl);
             if (port <= 0) {
-                av_strlcatf(buff, SDP_BUFFER_SIZE,
+                av_strlcatf(buff, size,
                                    "a=control:streamid=%d\r\n", i + j);
             }
         }
     }
 
-    return buff;
+    return 0;
 }
 #else
-char *avf_sdp_create(AVFormatContext *ac[], int n_files)
+int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size)
 {
-    return NULL;
+    return AVERROR(ENOSYS);
 }
 #endif