X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fecdec_filter.c;h=8cb17ad642098e81621e2be6f6c0643ac6de4038;hp=41db249e4ff46ab1eaa829b1e5cf73ea58998f58;hb=58151b60c9782a52aac5d39ace7e69c3635ee260;hpb=8c5c975d5e8f209919283373793c2751a719699b

diff --git a/fecdec_filter.c b/fecdec_filter.c
index 41db249e..8cb17ad6 100644
--- a/fecdec_filter.c
+++ b/fecdec_filter.c
@@ -70,20 +70,6 @@ struct fecdec_group {
 	unsigned char **data;
 };
 
-/**
- * The fecdec filter defers decoding of the first group until the first slice
- * of the next group was received. This avoids buffer underruns in subsequent
- * filters of the filter chain.
- */
-enum group_completion_status {
-	/** No complete group received so far. */
-	GCS_NO_COMPLETE_GROUP,
-	/** First group received, but not yet decoded. */
-	GCS_FIRST_GROUP_COMPLETE,
-	/** At least one complete group decoded. */
-	GCS_FIRST_GROUP_DECODED,
-};
-
 /**
  * Data private to the fecdec filter.
  */
@@ -94,8 +80,6 @@ struct private_fecdec_data {
 	struct fecdec_group groups[NUM_FEC_GROUPS];
 	/** Whether an audio file header was already received. */
 	int have_header;
-	/** See \ref group_completion_status. */
-	unsigned completion_status;
 	/** Points to the first received group. */
 	struct fecdec_group *first_complete_group;
 };
@@ -124,7 +108,9 @@ static void clear_group(struct fecdec_group *fg)
 		fg->idx[i] = -1;
 	}
 	free(fg->data);
+	fg->data = NULL;
 	free(fg->idx);
+	fg->idx = NULL;
 	fg->num_slices = 0;
 	memset(&fg->h, 0, sizeof(struct fec_header));
 	fg->num_received_slices = 0;
@@ -175,8 +161,7 @@ static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 		 * Don't clear the first complete group if it has not yet been
 		 * decoded.
 		 */
-		if (pfd->completion_status == GCS_FIRST_GROUP_COMPLETE
-				&& pfd->first_complete_group == fg)
+		if (fg == pfd->first_complete_group)
 			continue;
 		clear_group(fg);
 		return fg;
@@ -196,8 +181,8 @@ static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 		PARA_WARNING_LOG("Clearing incomplete group %d "
 			"(contains %d slices)\n", oldest->h.group_num,
 			oldest->num_received_slices);
-	assert(pfd->completion_status != GCS_FIRST_GROUP_COMPLETE
-		|| oldest != pfd->first_complete_group);
+	if (oldest == pfd->first_complete_group)
+		pfd->first_complete_group = NULL;
 	clear_group(oldest);
 	return oldest;
 }
@@ -390,37 +375,39 @@ static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 	ret = get_group(h, pfd, &fg);
 	if (ret < 0)
 		return ret;
-	if (!add_slice(buf, fg))
+	if (!add_slice(buf, fg)) /* group already complete */
 		return 1;
-	if (group_complete(fg)) {
-		if (pfd->completion_status == GCS_NO_COMPLETE_GROUP) {
-			pfd->completion_status = GCS_FIRST_GROUP_COMPLETE;
-			pfd->first_complete_group = fg;
+	if (!group_complete(fg))
+		return 1;
+	/* this slice completed the group */
+	if (pfd->fec)
+		goto decode;
+	/* it's either the first or the second complete group */
+	if (!pfd->first_complete_group) { /* it's the first group */
+		enum fec_group_usability u = group_is_usable(fg, pfd);
+		assert(u != FEC_GROUP_USABLE_SKIP_HEADER);
+		if (u == FEC_GROUP_UNUSABLE) /* forget it */
 			return 1;
-		}
-		assert(pfd->fec);
-		ret = decode_group(fg, fn);
-		if (ret < 0)
-			return ret;
+		pfd->first_complete_group = fg; /* remember it */
 		return 1;
 	}
-	if (pfd->completion_status == GCS_NO_COMPLETE_GROUP)
-		return 1;
-	if (pfd->completion_status == GCS_FIRST_GROUP_DECODED)
-		return 1;
-	if (fg == pfd->first_complete_group)
-		return 1;
-	assert(!pfd->fec);
+	/* we have two complete groups, let's go */
 	k = h->data_slices_per_group;
 	n = h->slices_per_group;
 	PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 	ret = fec_new(k, n, &pfd->fec);
 	if (ret < 0)
 		return ret;
+	/* decode and clear the first group */
 	ret = decode_group(pfd->first_complete_group, fn);
 	if (ret < 0)
 		return ret;
-	pfd->completion_status = GCS_FIRST_GROUP_DECODED;
+	clear_group(pfd->first_complete_group);
+	pfd->first_complete_group = NULL;
+decode:
+	ret = decode_group(fg, fn);
+	if (ret < 0)
+		return ret;
 	return 1;
 }
 
@@ -464,7 +451,6 @@ static void fecdec_open(struct filter_node *fn)
 	fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
 	fn->buf = para_malloc(fn->bufsize);
 	pfd = para_calloc(sizeof(*pfd));
-	pfd->completion_status = GCS_NO_COMPLETE_GROUP;
 	fn->private_data = pfd;
 	fn->loaded = 0;
 }