1 files changed, 148 insertions, 0 deletions
diff --git a/src/lb.cpp b/src/lb.cpp
new file mode 100644
index 0000000..51696ff
--- /dev/null
+++ b/src/lb.cpp
@@ -0,0 +1,148 @@
+/*
+    Copyright (c) 2010-2011 250bpm s.r.o.
+    Copyright (c) 2007-2009 iMatix Corporation
+    Copyright (c) 2011 VMware, Inc.
+    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 "lb.hpp"
+#include "pipe.hpp"
+#include "err.hpp"
+#include "msg.hpp"
+
+zmq::lb_t::lb_t () :
+    active (0),
+    current (0),
+    more (false),
+    dropping (false)
+{
+}
+
+zmq::lb_t::~lb_t ()
+{
+    zmq_assert (pipes.empty ());
+}
+
+void zmq::lb_t::attach (pipe_t *pipe_)
+{
+    pipes.push_back (pipe_);
+    activated (pipe_);
+}
+
+void zmq::lb_t::terminated (pipe_t *pipe_)
+{
+    pipes_t::size_type index = pipes.index (pipe_);
+
+    //  If we are in the middle of multipart message and current pipe
+    //  have disconnected, we have to drop the remainder of the message.
+    if (index == current && more)
+        dropping = true;
+
+    //  Remove the pipe from the list; adjust number of active pipes
+    //  accordingly.
+    if (index < active) {
+        active--;
+        pipes.swap (index, active);
+        if (current == active)
+            current = 0;
+    }
+    pipes.erase (pipe_);
+}
+
+void zmq::lb_t::activated (pipe_t *pipe_)
+{
+    //  Move the pipe to the list of active pipes.
+    pipes.swap (pipes.index (pipe_), active);
+    active++;
+}
+
+int zmq::lb_t::send (msg_t *msg_, int flags_)
+{
+    // flags_ is unused
+    (void)flags_;
+
+    //  Drop the message if required. If we are at the end of the message
+    //  switch back to non-dropping mode.
+    if (dropping) {
+
+        more = msg_->flags () & msg_t::more ? true : false;
+        dropping = more;
+
+        int rc = msg_->close ();
+        errno_assert (rc == 0);
+        rc = msg_->init ();
+        errno_assert (rc == 0);
+        return 0;
+    }
+
+    while (active > 0) {
+        if (pipes [current]->write (msg_))
+            break;
+
+        zmq_assert (!more);
+        active--;
+        if (current < active)
+            pipes.swap (current, active);
+        else
+            current = 0;
+    }
+
+    //  If there are no pipes we cannot send the message.
+    if (active == 0) {
+        errno = EAGAIN;
+        return -1;
+    }
+
+    //  If it's final part of the message we can fluch it downstream and
+    //  continue round-robinning (load balance).
+    more = msg_->flags () & msg_t::more? true: false;
+    if (!more) {
+        pipes [current]->flush ();
+        current = (current + 1) % active;
+    }
+
+    //  Detach the message from the data buffer.
+    int rc = msg_->init ();
+    errno_assert (rc == 0);
+
+    return 0;
+}
+
+bool zmq::lb_t::has_out ()
+{
+    //  If one part of the message was already written we can definitely
+    //  write the rest of the message.
+    if (more)
+        return true;
+
+    while (active > 0) {
+
+        //  Check whether a pipe has room for another message.
+        if (pipes [current]->check_write ())
+            return true;
+
+        //  Deactivate the pipe.
+        active--;
+        pipes.swap (current, active);
+        if (current == active)
+            current = 0;
+    }
+
+    return false;
+}
+