Imported Upstream version 2.0.7.dfsgupstream/2.0.7.dfsg

1 files changed, 180 insertions, 0 deletions

diff --git a/src/prefix_tree.cpp b/src/prefix_tree.cpp
new file mode 100644
index 0000000..51225d6
--- /dev/null
+++ b/src/prefix_tree.cpp
@@ -0,0 +1,180 @@
+/*
+    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 <stdlib.h>
+
+#include <new>
+#include <algorithm>
+
+#include "platform.hpp"
+#if defined ZMQ_HAVE_WINDOWS
+#include "windows.hpp"
+#endif
+
+#include "err.hpp"
+#include "prefix_tree.hpp"
+
+zmq::prefix_tree_t::prefix_tree_t () :
+    refcnt (0),
+    min (0),
+    count (0)
+{
+}
+
+zmq::prefix_tree_t::~prefix_tree_t ()
+{
+    if (count == 1)
+        delete next.node;
+    else if (count > 1) {
+        for (unsigned char i = 0; i != count; ++i)
+            if (next.table [i])
+                delete next.table [i];
+        free (next.table);
+    }
+}
+
+void zmq::prefix_tree_t::add (unsigned char *prefix_, size_t size_)
+{
+    //  We are at the node corresponding to the prefix. We are done.
+    if (!size_) {
+        ++refcnt;
+        return;
+    }
+
+    unsigned char c = *prefix_;
+    if (c < min || c >= min + count) {
+
+        //  The character is out of range of currently handled
+        //  charcters. We have to extend the table.
+        if (!count) {
+            min = c;
+            count = 1;
+            next.node = NULL;
+        }
+        else if (count == 1) {
+            unsigned char oldc = min;
+            prefix_tree_t *oldp = next.node;
+            count = (min < c ? c - min : min - c) + 1;
+            next.table = (prefix_tree_t**)
+                malloc (sizeof (prefix_tree_t*) * count);
+            zmq_assert (next.table);
+            for (unsigned char i = 0; i != count; ++i)
+                next.table [i] = 0;
+            min = std::min (min, c);
+            next.table [oldc - min] = oldp;
+        }
+        else if (min < c) {
+
+            //  The new character is above the current character range.
+            unsigned char old_count = count;
+            count = c - min + 1;
+            next.table = (prefix_tree_t**) realloc ((void*) next.table,
+                sizeof (prefix_tree_t*) * count);
+            zmq_assert (next.table);
+            for (unsigned char i = old_count; i != count; i++)
+                next.table [i] = NULL;
+        }
+        else {
+
+            //  The new character is below the current character range.
+            unsigned char old_count = count;
+            count = (min + old_count) - c;
+            next.table = (prefix_tree_t**) realloc ((void*) next.table,
+                sizeof (prefix_tree_t*) * count);
+            zmq_assert (next.table);
+            memmove (next.table + min - c, next.table,
+                old_count * sizeof (prefix_tree_t*));
+            for (unsigned char i = 0; i != min - c; i++)
+                next.table [i] = NULL;
+            min = c;
+        }
+    }
+
+    //  If next node does not exist, create one.
+    if (count == 1) {
+        if (!next.node) {
+            next.node = new (std::nothrow) prefix_tree_t;
+            zmq_assert (next.node);
+        }
+        next.node->add (prefix_ + 1, size_ - 1);
+    }
+    else {
+        if (!next.table [c - min]) {
+            next.table [c - min] = new (std::nothrow) prefix_tree_t;
+            zmq_assert (next.table [c - min]);
+        }
+        next.table [c - min]->add (prefix_ + 1, size_ - 1);
+    }
+}
+
+bool zmq::prefix_tree_t::rm (unsigned char *prefix_, size_t size_)
+{
+     if (!size_) {
+         if (!refcnt)
+             return false;
+         refcnt--;
+         return true;
+     }
+
+     unsigned char c = *prefix_;
+     if (!count || c < min || c >= min + count)
+         return false;
+
+     prefix_tree_t *next_node =
+         count == 1 ? next.node : next.table [c - min];
+
+     if (!next_node)
+         return false;
+
+     return next_node->rm (prefix_ + 1, size_ - 1);
+}
+
+bool zmq::prefix_tree_t::check (unsigned char *data_, size_t size_)
+{
+    //  This function is on critical path. It deliberately doesn't use
+    //  recursion to get a bit better performance.
+    prefix_tree_t *current = this;
+    while (true) {
+
+        //  We've found a corresponding subscription!
+        if (current->refcnt)
+            return true;
+
+        //  We've checked all the data and haven't found matching subscription.
+        if (!size_)
+            return false;
+
+        //  If there's no corresponding slot for the first character
+        //  of the prefix, the message does not match.
+        unsigned char c = *data_;
+        if (c < current->min || c >= current->min + current->count)
+            return false;
+
+        //  Move to the next character.
+        if (current->count == 1)
+            current = current->next.node;
+        else {
+            current = current->next.table [c - current->min];
+            if (!current)
+                return false;
+        }
+        data_++;
+        size_--;
+    }
+}