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+/*
+ Copyright (c) 2007-2009 FastMQ Inc.
+
+ This file is part of 0MQ.
+
+ 0MQ is free software; you can redistribute it and/or modify it under
+ the terms of the Lesser GNU 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
+ Lesser GNU General Public License for more details.
+
+ You should have received a copy of the Lesser GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "../bindings/c/zmq.h"
+
+#include "lb.hpp"
+#include "pipe.hpp"
+#include "err.hpp"
+
+zmq::lb_t::lb_t () :
+ active (0),
+ current (0)
+{
+}
+
+zmq::lb_t::~lb_t ()
+{
+ for (pipes_t::size_type i = 0; i != pipes.size (); i++)
+ pipes [i]->term ();
+}
+
+void zmq::lb_t::attach (writer_t *pipe_)
+{
+ pipes.push_back (pipe_);
+ pipes.swap (active, pipes.size () - 1);
+ active++;
+}
+
+void zmq::lb_t::detach (writer_t *pipe_)
+{
+ // Remove the pipe from the list; adjust number of active pipes
+ // accordingly.
+ if (pipes.index (pipe_) < active)
+ active--;
+ pipes.erase (pipe_);
+}
+
+void zmq::lb_t::kill (writer_t *pipe_)
+{
+ // Move the pipe to the list of inactive pipes.
+ active--;
+ pipes.swap (pipes.index (pipe_), active);
+}
+
+void zmq::lb_t::revive (writer_t *pipe_)
+{
+ // Move the pipe to the list of active pipes.
+ pipes.swap (pipes.index (pipe_), active);
+ active++;
+}
+
+int zmq::lb_t::send (zmq_msg_t *msg_, int flags_)
+{
+ // If there are no pipes we cannot send the message.
+ if (pipes.empty ()) {
+ errno = EAGAIN;
+ return -1;
+ }
+
+ // Move to the next pipe (load-balancing).
+ current++;
+ if (current >= active)
+ current = 0;
+
+ // TODO: Implement this once queue limits are in-place.
+ zmq_assert (pipes [current]->check_write (zmq_msg_size (msg_)));
+
+ // Push message to the selected pipe.
+ pipes [current]->write (msg_);
+ pipes [current]->flush ();
+
+ // Detach the message from the data buffer.
+ int rc = zmq_msg_init (msg_);
+ zmq_assert (rc == 0);
+
+ return 0;
+}
+
+bool zmq::lb_t::has_out ()
+{
+ for (int count = active; count != 0; count--) {
+
+ // We should be able to write at least 1-byte message to interrupt
+ // polling for POLLOUT.
+ // TODO: Shouldn't we use a saner value here?
+ if (pipes [current]->check_write (1))
+ return true;
+ current++;
+ if (current >= active)
+ current = 0;
+ }
+
+ return false;
+}
+