X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=vss.c;h=4a8aafa8d6e0c2ae239d09342ac10f3b08263828;hp=e833543e785788876af91d691b73cf8876899de3;hb=3150a0caa27a34d44556fb77f4a5aebc3d978580;hpb=7bba6232e873b7a6acc95ac05b4e333f86a51a46

diff --git a/vss.c b/vss.c
index e833543e..4a8aafa8 100644
--- a/vss.c
+++ b/vss.c
@@ -132,6 +132,7 @@ struct fec_group {
 	uint16_t slice_bytes;
 };
 
+/** A FEC client is always in one of these states. */
 enum fec_client_state {
 	FEC_STATE_NONE = 0,	/**< not initialized and not enabled */
 	FEC_STATE_DISABLED,	/**< temporarily disabled */
@@ -360,8 +361,17 @@ static void vss_get_chunk(int chunk_num, struct vss_task *vsst,
 static void compute_group_size(struct vss_task *vsst, struct fec_group *g,
 		int max_bytes)
 {
+	char *buf;
+	size_t len;
 	int i, max_chunks = PARA_MAX(1LU, 150 / tv2ms(vss_chunk_time()));
 
+	if (g->first_chunk == 0) {
+		g->num_chunks = 1;
+		vss_get_chunk(0, vsst, &buf, &len);
+		g->bytes = len;
+		return;
+	}
+
 	g->num_chunks = 0;
 	g->bytes = 0;
 	/*
@@ -371,8 +381,6 @@ static void compute_group_size(struct vss_task *vsst, struct fec_group *g,
 	 * of exactly one chunk for these audio formats.
 	 */
 	for (i = 0;; i++) {
-		char *buf;
-		size_t len;
 		int chunk_num = g->first_chunk + i;
 
 		if (g->bytes > 0 && i >= max_chunks) /* duration limit */
@@ -501,7 +509,7 @@ static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 {
 	int ret, i, k, n, data_slices;
 	size_t len;
-	char *buf;
+	char *buf, *p;
 	struct fec_group *g = &fc->group;
 
 	if (fc->state == FEC_STATE_NONE) {
@@ -561,16 +569,20 @@ static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 		assert(i == g->num_header_slices - 1);
 	}
 
-	/* setup data slices */
+	/*
+	 * Setup data slices. Note that for ogg streams chunk 0 points to a
+	 * buffer on the heap rather than to the mapped audio file.
+	 */
 	vss_get_chunk(g->first_chunk, vsst, &buf, &len);
-	for (; i < g->num_header_slices + data_slices; i++) {
-		if (buf + g->slice_bytes > vsst->map + mmd->size) {
+	for (p = buf; i < g->num_header_slices + data_slices; i++) {
+		if (p + g->slice_bytes > buf + g->bytes) {
 			/*
-			 * Can not use the memory mapped audio file for this
-			 * slice as it goes beyond the map.
+			 * We must make a copy for this slice since using p
+			 * directly would exceed the buffer.
 			 */
-			uint32_t payload_size = vsst->map + mmd->size - buf;
-			memcpy(fc->extra_src_buf, buf, payload_size);
+			uint32_t payload_size = buf + g->bytes - p;
+			assert(payload_size + FEC_HEADER_SIZE <= fc->mps);
+			memcpy(fc->extra_src_buf, p, payload_size);
 			if (payload_size < g->slice_bytes)
 				memset(fc->extra_src_buf + payload_size, 0,
 					g->slice_bytes - payload_size);
@@ -578,8 +590,8 @@ static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 			i++;
 			break;
 		}
-		fc->src_data[i] = (const unsigned char *)buf;
-		buf += g->slice_bytes;
+		fc->src_data[i] = (const unsigned char *)p;
+		p += g->slice_bytes;
 	}
 	if (i < k) {
 		/* use arbitrary data for all remaining slices */
@@ -1078,8 +1090,6 @@ static void vss_send(struct vss_task *vsst)
 			senders[i].send(mmd->current_chunk, mmd->chunks_sent,
 				buf, len, vsst->header_buf, vsst->header_len);
 		}
-		mmd->chunks_sent++;
-		mmd->current_chunk++;
 		/*
 		 * Prefault next chunk(s)
 		 *
@@ -1092,11 +1102,15 @@ static void vss_send(struct vss_task *vsst)
 		 * eliminate the delays completely. Moreover, it is supported
 		 * only on Linux. So we do our own read-ahead here.
 		 */
-		buf += len;
-		for (i = 0; i < 5 && buf < vsst->map + mmd->size; i++) {
-			__a_unused volatile char x = *buf;
-			buf += 4096;
+		if (mmd->current_chunk > 0) { /* chunk 0 might be on the heap */
+			buf += len;
+			for (i = 0; i < 5 && buf < vsst->map + mmd->size; i++) {
+				__a_unused volatile char x = *buf;
+				buf += 4096;
+			}
 		}
+		mmd->chunks_sent++;
+		mmd->current_chunk++;
 	}
 }