1 files changed, 66 insertions, 39 deletions

diff --git a/mcastseed/src/dgrambuf.c b/mcastseed/src/dgrambuf.c
index b19b698..41ebc8a 100644
--- a/mcastseed/src/dgrambuf.c
+++ b/mcastseed/src/dgrambuf.c
@@ -33,6 +33,7 @@ struct dgrambuf_t {
 	unsigned int dgram_seq_base;
 	unsigned int *dgram_len;
 	unsigned int *dgram_seq_numbers; /* Stores the decoded datagram sequence number for each dgram slot of buf */
+	int dgram_ordered_seq_numbers_is_dirty;
 	struct uint_pair *dgram_ordered_seq_numbers;
 
 	void *buf;
@@ -42,6 +43,7 @@ struct dgrambuf_t {
 };
 
 int _compare_uint_pair(const void *pa, const void *pb);
+void _update_ordered_seq_numbers(dgrambuf_t dbuf);
 
 void dgrambuf_set_validate_func(dgrambuf_t dbuf, unsigned int (*func)(unsigned int, void *) ) {
 	dbuf->validate_func = func;
@@ -52,7 +54,7 @@ size_t dgrambuf_free_count(const dgrambuf_t dbuf) {
 }
 
 int dgrambuf_recvmmsg(dgrambuf_t dbuf, int sockfd) {
-  void *dgram_base;
+	void *dgram_base;
 	size_t vlen, i, dgram_index;
 	int recv_msg_count, res;
 	unsigned int seq, dgram_len;
@@ -87,6 +89,9 @@ int dgrambuf_recvmmsg(dgrambuf_t dbuf, int sockfd) {
 		perror("recvmmsg()");
 		return recv_msg_count;
 	}
+	if (recv_msg_count > 0) {
+		dbuf->dgram_ordered_seq_numbers_is_dirty = 1;
+	}
 
 	/* Check all received messages */
 	res = 1;
@@ -95,23 +100,21 @@ int dgrambuf_recvmmsg(dgrambuf_t dbuf, int sockfd) {
 		dgram_index = (dgram_base - dbuf->buf) / dbuf->dgram_max_size;
 		dgram_len = dbuf->msgs[i].msg_len;
 		seq = dbuf->validate_func(dgram_len, dgram_base);
+
 		// TODO better feedback
-		if ( seq == 0 ) {
-			fprintf(stderr, "dgrambuf_recvmmsg(): #%zi invalid (%u)\n", i, seq);
-			dbuf->dgram_seq_numbers[dgram_index] = 0;
-		} else if ( seq == -1 ) {
+		if ( seq == -1 ) {
 			fprintf(stderr, "dgrambuf_recvmmsg(): #%zi end\n", i);
-			dbuf->dgram_seq_numbers[dgram_index] = 0;
 			res = 0;
+		} else if ( seq == 0 ) {
+			fprintf(stderr, "dgrambuf_recvmmsg(): #%zi invalid (%u)\n", i, seq);
 		} else if ( seq < dbuf->dgram_seq_base ) {
 			fprintf(stderr, "dgrambuf_recvmmsg(): #%zi past (%u)\n", i, seq);
-			dbuf->dgram_seq_numbers[dgram_index] = 0;
 		} else if ( seq >= dbuf->dgram_seq_base + dbuf->dgram_slots ) {
 			fprintf(stderr, "dgrambuf_recvmmsg(): #%zi future (%u)\n", i, seq);
-			dbuf->dgram_seq_numbers[dgram_index] = 0;
 		} else {
 			//fprintf(stderr, "dgrambuf_recvmmsg(): #%zi valid (%u)\n", i, seq);
 			dbuf->dgram_seq_numbers[dgram_index] = seq;
+			dbuf->dgram_ordered_seq_numbers_is_dirty = 1;
 			dbuf->dgram_len[dgram_index] = dgram_len;
 			dbuf->dgram_free_count--;
 		}
@@ -120,27 +123,39 @@ int dgrambuf_recvmmsg(dgrambuf_t dbuf, int sockfd) {
 	return res;
 }
 
+int dgrambuf_have_data_ready_to_write(dgrambuf_t dbuf) {
+	unsigned int next_dgram_seq;
+	/* Buffer is empty, nothing to write */
+	if ( dbuf->dgram_free_count == dbuf->dgram_slots ) {
+		return 0;
+	}
+
+	/* Other test cases needs ordered_seq_numbers */
+	if ( dbuf->dgram_ordered_seq_numbers_is_dirty ) {
+		_update_ordered_seq_numbers(dbuf);
+	}
+
+	/* Nothing to write if next dgram is not in buffer at all */
+	next_dgram_seq = dbuf->dgram_ordered_seq_numbers[dbuf->dgram_free_count].value;
+	if ( next_dgram_seq != dbuf->dgram_seq_base ) {
+		return 0;
+	}
+	/* At least some data of one dgram is availble for writing out */
+	return 1;
+}
+
 ssize_t dgrambuf_write(dgrambuf_t dbuf, int fd) {
 	size_t dgram_index, i, vlen;
 	unsigned int curr_seq, prev_seq, dgram_len;
 	ssize_t nwrite, total;
 
-	/* Buffer is empty, nothing to write */
-	if ( dbuf->dgram_free_count == dbuf->dgram_slots ) {
-		return -1;
-	}
-
-	/* Initialize dgram_ordered_seq_numbers from dgram_seq_numbers */
-	for (i=0; i < dbuf->dgram_slots; i++) {
-		dbuf->dgram_ordered_seq_numbers[i].index = i;
-		dbuf->dgram_ordered_seq_numbers[i].value = dbuf->dgram_seq_numbers[i];
+	/* Write needs up to date ordered_seq_numbers */
+	if ( dbuf->dgram_ordered_seq_numbers_is_dirty ) {
+		_update_ordered_seq_numbers(dbuf);
 	}
-	/* Inplace sorting of dgram_ordered_seq_numbers */
-	qsort(dbuf->dgram_ordered_seq_numbers, dbuf->dgram_slots, sizeof(struct uint_pair), _compare_uint_pair);
-	
 	/* Initialize iovecs for writev, take dgram payloads following the sequence numbers */
-	prev_seq=0, vlen=0, total=0;
-	for (i=dbuf->dgram_free_count; i < dbuf->dgram_slots; i++) {
+	prev_seq=0, total=0;
+	for (i=dbuf->dgram_free_count, vlen=0; i < dbuf->dgram_slots && vlen < dbuf->iovec_slots; i++) {
 		curr_seq = dbuf->dgram_ordered_seq_numbers[i].value;
 
 		/* Skip empty dgram slot */
@@ -148,28 +163,20 @@ ssize_t dgrambuf_write(dgrambuf_t dbuf, int fd) {
 			fprintf(stderr, "Oops : found empty slot (i==%zi)\n", i);
 			continue;
 		}
-
 		/* Skip if current dgram is a dup of the previous */
 		if ( curr_seq == prev_seq ) {
-			dgram_index = dbuf->dgram_ordered_seq_numbers[i].index;
-			/* Mark slot as empty */
-			dbuf->dgram_seq_numbers[dgram_index] = 0;
-			dbuf->dgram_free_count++;
-			continue;
+			goto mark_empty;
 		}
-
 		/* Skip dgram comming from the past */
 		if ( curr_seq < dbuf->dgram_seq_base ) {
 			fprintf(stderr, "Oops : found dgram from past in buffer (%u)\n", curr_seq);
-			continue;
+			goto mark_empty;
 		}
-
 		/* Stop if first dgram to write is not in buffer at all */
 		if ( ( vlen==0 ) && (curr_seq != dbuf->dgram_seq_base) ) {
 			fprintf(stderr, "Oops : nothing to write, missing %u seq\n", dbuf->dgram_seq_base);
 			break;
 		}
-
 		/* Stop if current seq dgram is missing */
 		if ( ( vlen > 0 ) && (curr_seq > prev_seq+1 ) ) {
 			break;
@@ -179,22 +186,28 @@ ssize_t dgrambuf_write(dgrambuf_t dbuf, int fd) {
 		dgram_index = dbuf->dgram_ordered_seq_numbers[i].index;
 		dgram_len = dbuf->dgram_len[dgram_index] - dbuf->dgram_header_size;
 
-		dbuf->iov_write[vlen].iov_len = dgram_len; /* Setup iovecs */
+		/* Setup iovecs */
+		dbuf->iov_write[vlen].iov_len = dgram_len;
 		dbuf->iov_write[vlen].iov_base = dbuf->buf + dgram_index*dbuf->dgram_max_size + dbuf->dgram_header_size;
-		dbuf->dgram_seq_numbers[dgram_index] = 0; /* Mark dgram slots about to be written out as empty for next read */
 
-		total += dgram_len; /* Update counters */
-		dbuf->dgram_free_count++;
+		/* Update counters */
+		total += dgram_len;
 		dbuf->dgram_seq_base = curr_seq + 1;
 		prev_seq = curr_seq;
 		vlen++;
-		/* Don't plan to write more than iovec_slots slots */
-		if ( vlen == dbuf->iovec_slots )
-			break;
+
+		/* Mark dgram slot about to be written out as empty for next read */
+		//XXX These cause harm if writev() is incomplete
+mark_empty:
+		/* Mark slot as empty */
+		dgram_index = dbuf->dgram_ordered_seq_numbers[i].index;
+		dbuf->dgram_seq_numbers[dgram_index] = 0;
+		dbuf->dgram_free_count++;
 	}
 
 	/* Nothing valid to write out (but buffer not empty, missing the next dgram) */
 	if ( vlen == 0 ) {
+		fprintf(stderr, "Oops : nothing to write at all\n");
 		return -1;
 	}
 
@@ -239,6 +252,7 @@ dgrambuf_t dgrambuf_new(size_t dgram_slots, size_t dgram_max_size, size_t dgram_
 
 	dbuf->dgram_ordered_seq_numbers = calloc(dgram_slots, sizeof(struct uint_pair));
 	if (!dbuf->dgram_ordered_seq_numbers) goto fail6;
+	dbuf->dgram_ordered_seq_numbers_is_dirty = 1;
 
 	dbuf->buf = calloc(dgram_slots, dgram_max_size);
 	if (!dbuf->buf) goto fail7;
@@ -280,3 +294,16 @@ int _compare_uint_pair(const void *pa, const void *pb) {
 		return 0;
 }
 
+void _update_ordered_seq_numbers(dgrambuf_t dbuf) {
+	ssize_t i;
+	/* Initialize dgram_ordered_seq_numbers from dgram_seq_numbers */
+	for (i=0; i < dbuf->dgram_slots; i++) {
+		dbuf->dgram_ordered_seq_numbers[i].index = i;
+		dbuf->dgram_ordered_seq_numbers[i].value = dbuf->dgram_seq_numbers[i];
+	}
+	/* Inplace sorting of dgram_ordered_seq_numbers */
+	qsort(dbuf->dgram_ordered_seq_numbers, dbuf->dgram_slots, sizeof(struct uint_pair), _compare_uint_pair);
+
+	dbuf->dgram_ordered_seq_numbers_is_dirty = 0;
+}
+