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+/*
+ Copyright (c) 2007-2010 iMatix Corporation
+
+ 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 "../include/zmq.h"
+
+#include "fq.hpp"
+#include "pipe.hpp"
+#include "err.hpp"
+
+zmq::fq_t::fq_t () :
+ active (0),
+ current (0),
+ more (false)
+{
+}
+
+zmq::fq_t::~fq_t ()
+{
+ for (pipes_t::size_type i = 0; i != pipes.size (); i++)
+ pipes [i]->term ();
+}
+
+void zmq::fq_t::attach (reader_t *pipe_)
+{
+ pipes.push_back (pipe_);
+ pipes.swap (active, pipes.size () - 1);
+ active++;
+}
+
+void zmq::fq_t::detach (reader_t *pipe_)
+{
+ zmq_assert (!more || pipes [current] != pipe_);
+
+ // Remove the pipe from the list; adjust number of active pipes
+ // accordingly.
+ if (pipes.index (pipe_) < active) {
+ active--;
+ if (current == active)
+ current = 0;
+ }
+ pipes.erase (pipe_);
+}
+
+void zmq::fq_t::kill (reader_t *pipe_)
+{
+ // Move the pipe to the list of inactive pipes.
+ active--;
+ if (current == active)
+ current = 0;
+ pipes.swap (pipes.index (pipe_), active);
+}
+
+void zmq::fq_t::revive (reader_t *pipe_)
+{
+ // Move the pipe to the list of active pipes.
+ pipes.swap (pipes.index (pipe_), active);
+ active++;
+}
+
+int zmq::fq_t::recv (zmq_msg_t *msg_, int flags_)
+{
+ // Deallocate old content of the message.
+ zmq_msg_close (msg_);
+
+ // Round-robin over the pipes to get the next message.
+ for (int count = active; count != 0; count--) {
+
+ // Try to fetch new message. If we've already read part of the message
+ // subsequent part should be immediately available.
+ bool fetched = pipes [current]->read (msg_);
+ zmq_assert (!(more && !fetched));
+
+ // Note that when message is not fetched, current pipe is killed and
+ // replaced by another active pipe. Thus we don't have to increase
+ // the 'current' pointer.
+ if (fetched) {
+ more = msg_->flags & ZMQ_MSG_MORE;
+ if (!more) {
+ current++;
+ if (current >= active)
+ current = 0;
+ }
+ return 0;
+ }
+ }
+
+ // No message is available. Initialise the output parameter
+ // to be a 0-byte message.
+ zmq_msg_init (msg_);
+ errno = EAGAIN;
+ return -1;
+}
+
+bool zmq::fq_t::has_in ()
+{
+ // There are subsequent parts of the partly-read message available.
+ if (more)
+ return true;
+
+ // Note that messing with current doesn't break the fairness of fair
+ // queueing algorithm. If there are no messages available current will
+ // get back to its original value. Otherwise it'll point to the first
+ // pipe holding messages, skipping only pipes with no messages available.
+ for (int count = active; count != 0; count--) {
+ if (pipes [current]->check_read ())
+ return true;
+ current++;
+ if (current >= active)
+ current = 0;
+ }
+
+ return false;
+}
+