1 files changed, 108 insertions, 0 deletions
diff --git a/src/prefix_filter.hpp b/src/prefix_filter.hpp
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+++ b/src/prefix_filter.hpp
@@ -0,0 +1,108 @@
+/*
+    Copyright (c) 2012 250bpm s.r.o.
+    Copyright (c) 2011-2012 Spotify AB
+    Copyright (c) 2012 Other contributors as noted in the AUTHORS file
+
+    This file is part of Crossroads I/O project.
+
+    Crossroads I/O 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.
+
+    Crossroads 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/>.
+*/
+
+#ifndef __XS_PREFIX_FILTER_HPP_INCLUDED__
+#define __XS_PREFIX_FILTER_HPP_INCLUDED__
+
+#include <stddef.h>
+#include <map>
+
+#include "stdint.hpp"
+
+namespace xs
+{
+
+    //  Canonical extension object.
+    extern void *prefix_filter;
+
+    class prefix_filter_t
+    {
+    public:
+
+        prefix_filter_t ();
+        ~prefix_filter_t ();
+
+        int subscribe (void *core_, void *subscriber_,
+            const unsigned char *data_, size_t size_);
+        int unsubscribe (void *core_, void *subscriber_,
+            const unsigned char *data_, size_t size_);
+        void unsubscribe_all (void *core_, void *subscriber_);
+        void enumerate (void *core_);
+        int match (void *core_, const unsigned char *data_, size_t size_);
+        void match_all (void *core_, const unsigned char *data_, size_t size_);
+
+    private:
+
+        struct node_t
+        {
+            //  Pointer to particular subscriber associated with
+            //  the reference count.
+            typedef std::map <void*, int> subscribers_t;
+            subscribers_t *subscribers;
+
+            unsigned char min;
+            unsigned short count;
+            unsigned short live_nodes;
+            union {
+                struct node_t *node;
+                struct node_t **table;
+            } next;
+
+        };
+
+        static void init (node_t *node_);
+        static void close (node_t *node_);
+
+        //  Add key to the trie. Returns true if it's a new subscription
+        //  rather than a duplicate.
+        static bool add (node_t *node_, const unsigned char *prefix_,
+            size_t size_, void *subscriber_);
+
+        //  Remove specific subscription from the trie. Return true is it
+        //  was actually removed rather than de-duplicated.
+        static bool rm (node_t *node_, const unsigned char *prefix_,
+            size_t size_, void *subscriber_);
+
+        //  Remove all subscriptions for a specific peer from the trie.
+        //  If there are no subscriptions left on some topics, invoke the
+        //  supplied callback function.
+        static void rm (node_t *node_, void *subscriber_, void *arg_);
+
+        static void rm_helper (node_t *node_, void *subscriber_,
+            unsigned char **buff_, size_t buffsize_, size_t maxbuffsize_,
+            void *arg_);
+
+        //  Lists all the subscriptions in the trie.
+        static void list (node_t *node_, unsigned char **buff_,
+            size_t buffsize_, size_t maxbuffsize_, void *arg_);
+
+        //  Checks whether node can be safely removed.
+        static bool is_redundant (node_t *node_);
+
+        node_t root;
+
+        prefix_filter_t (const prefix_filter_t&);
+        const prefix_filter_t &operator = (const prefix_filter_t&);
+    };
+
+}
+
+#endif