matroskadec: simplify parsing of the first cluster

Now that we save the currently parsed ebml element ID after an interruption,
we don't need to special case the parsing of the first cluster.

Originally committed as revision 23588 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/matroskadec.c

@@ -235,7 +235,6 @@ typedef struct {
     AVPacket *prev_pkt;
 
     int done;
-    int has_cluster_id;
 
     /* What to skip before effectively reading a packet. */
     int skip_to_keyframe;
@@ -471,7 +470,7 @@ static EbmlSyntax matroska_segment[] = {
     { MATROSKA_ID_CUES,           EBML_NEST, 0, 0, {.n=matroska_index      } },
     { MATROSKA_ID_TAGS,           EBML_NEST, 0, 0, {.n=matroska_tags       } },
     { MATROSKA_ID_SEEKHEAD,       EBML_NEST, 0, 0, {.n=matroska_seekhead   } },
-    { MATROSKA_ID_CLUSTER,        EBML_STOP, 0, offsetof(MatroskaDemuxContext,has_cluster_id) },
+    { MATROSKA_ID_CLUSTER,        EBML_STOP },
     { 0 }
 };
 
@@ -795,7 +794,7 @@ static int ebml_parse_elem(MatroskaDemuxContext *matroska,
                          matroska->segment_start = url_ftell(matroska->ctx->pb);
                      return ebml_parse_nest(matroska, syntax->def.n, data);
     case EBML_PASS:  return ebml_parse_id(matroska, syntax->def.n, id, data);
-    case EBML_STOP:  *(int *)data = 1;      return 1;
+    case EBML_STOP:  return 1;
     default:         return url_fseek(pb,length,SEEK_CUR)<0 ? AVERROR(EIO) : 0;
     }
     if (res == AVERROR_INVALIDDATA)
@@ -1797,14 +1796,8 @@ static int matroska_parse_cluster(MatroskaDemuxContext *matroska)
     int i, res;
     int64_t pos = url_ftell(matroska->ctx->pb);
     matroska->prev_pkt = NULL;
-    if (matroska->has_cluster_id){
-        /* For the first cluster we parse, its ID was already read as
-           part of matroska_read_header(), so don't read it again */
-        res = ebml_parse_id(matroska, matroska_clusters,
-                            MATROSKA_ID_CLUSTER, &cluster);
+    if (matroska->current_id)
         pos -= 4;  /* sizeof the ID which was already read */
-        matroska->has_cluster_id = 0;
-    } else
         res = ebml_parse(matroska, matroska_clusters, &cluster);
     blocks_list = &cluster.blocks;
     blocks = blocks_list->elem;