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+/*
+ Copyright (c) 2007-2011 iMatix Corporation
+ Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
+
+ This file is part of 0MQ.
+
+ 0MQ is free software; you can redistribute it and/or modify it under
+ the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ 0MQ is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <string.h>
+
+#include "../include/zmq.h"
+
+#include "xsub.hpp"
+#include "err.hpp"
+
+zmq::xsub_t::xsub_t (class ctx_t *parent_, uint32_t tid_) :
+ socket_base_t (parent_, tid_),
+ fq (this),
+ has_message (false),
+ more (false)
+{
+ options.type = ZMQ_XSUB;
+ options.requires_in = true;
+ options.requires_out = false;
+ zmq_msg_init (&message);
+}
+
+zmq::xsub_t::~xsub_t ()
+{
+ zmq_msg_close (&message);
+}
+
+void zmq::xsub_t::xattach_pipes (class reader_t *inpipe_,
+ class writer_t *outpipe_, const blob_t &peer_identity_)
+{
+ zmq_assert (inpipe_ && !outpipe_);
+ fq.attach (inpipe_);
+}
+
+void zmq::xsub_t::process_term (int linger_)
+{
+ fq.terminate ();
+ socket_base_t::process_term (linger_);
+}
+
+int zmq::xsub_t::xsend (zmq_msg_t *msg_, int options_)
+{
+ size_t size = zmq_msg_size (msg_);
+ unsigned char *data = (unsigned char*) zmq_msg_data (msg_);
+
+ // Malformed subscriptions are dropped silently.
+ if (size >= 1) {
+
+ // Process a subscription.
+ if (*data == 1)
+ subscriptions.add (data + 1, size - 1);
+
+ // Process an unsubscription. Invalid unsubscription is ignored.
+ if (*data == 0)
+ subscriptions.rm (data + 1, size - 1);
+ }
+
+ int rc = zmq_msg_close (msg_);
+ zmq_assert (rc == 0);
+ rc = zmq_msg_init (msg_);
+ zmq_assert (rc == 0);
+ return 0;
+}
+
+bool zmq::xsub_t::xhas_out ()
+{
+ // Subscription can be added/removed anytime.
+ return true;
+}
+
+int zmq::xsub_t::xrecv (zmq_msg_t *msg_, int flags_)
+{
+ // If there's already a message prepared by a previous call to zmq_poll,
+ // return it straight ahead.
+ if (has_message) {
+ zmq_msg_move (msg_, &message);
+ has_message = false;
+ more = msg_->flags & ZMQ_MSG_MORE;
+ return 0;
+ }
+
+ // TODO: This can result in infinite loop in the case of continuous
+ // stream of non-matching messages which breaks the non-blocking recv
+ // semantics.
+ while (true) {
+
+ // Get a message using fair queueing algorithm.
+ int rc = fq.recv (msg_, flags_);
+
+ // If there's no message available, return immediately.
+ // The same when error occurs.
+ if (rc != 0)
+ return -1;
+
+ // Check whether the message matches at least one subscription.
+ // Non-initial parts of the message are passed
+ if (more || match (msg_)) {
+ more = msg_->flags & ZMQ_MSG_MORE;
+ return 0;
+ }
+
+ // Message doesn't match. Pop any remaining parts of the message
+ // from the pipe.
+ while (msg_->flags & ZMQ_MSG_MORE) {
+ rc = fq.recv (msg_, ZMQ_NOBLOCK);
+ zmq_assert (rc == 0);
+ }
+ }
+}
+
+bool zmq::xsub_t::xhas_in ()
+{
+ // There are subsequent parts of the partly-read message available.
+ if (more)
+ return true;
+
+ // If there's already a message prepared by a previous call to zmq_poll,
+ // return straight ahead.
+ if (has_message)
+ return true;
+
+ // TODO: This can result in infinite loop in the case of continuous
+ // stream of non-matching messages.
+ while (true) {
+
+ // Get a message using fair queueing algorithm.
+ int rc = fq.recv (&message, ZMQ_NOBLOCK);
+
+ // If there's no message available, return immediately.
+ // The same when error occurs.
+ if (rc != 0) {
+ zmq_assert (errno == EAGAIN);
+ return false;
+ }
+
+ // Check whether the message matches at least one subscription.
+ if (match (&message)) {
+ has_message = true;
+ return true;
+ }
+
+ // Message doesn't match. Pop any remaining parts of the message
+ // from the pipe.
+ while (message.flags & ZMQ_MSG_MORE) {
+ rc = fq.recv (&message, ZMQ_NOBLOCK);
+ zmq_assert (rc == 0);
+ }
+ }
+}
+
+bool zmq::xsub_t::match (zmq_msg_t *msg_)
+{
+ return subscriptions.check ((unsigned char*) zmq_msg_data (msg_),
+ zmq_msg_size (msg_));
+}