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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 <stdlib.h>
+
+#include <new>
+#include <algorithm>
+
+#include "platform.hpp"
+#if defined ZMQ_HAVE_WINDOWS
+#include "windows.hpp"
+#endif
+
+#include "err.hpp"
+#include "trie.hpp"
+
+zmq::trie_t::trie_t () :
+ refcnt (0),
+ min (0),
+ count (0)
+{
+}
+
+zmq::trie_t::~trie_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::trie_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;
+ trie_t *oldp = next.node;
+ count = (min < c ? c - min : min - c) + 1;
+ next.table = (trie_t**)
+ malloc (sizeof (trie_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 = (trie_t**) realloc ((void*) next.table,
+ sizeof (trie_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 = (trie_t**) realloc ((void*) next.table,
+ sizeof (trie_t*) * count);
+ zmq_assert (next.table);
+ memmove (next.table + min - c, next.table,
+ old_count * sizeof (trie_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) trie_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) trie_t;
+ zmq_assert (next.table [c - min]);
+ }
+ next.table [c - min]->add (prefix_ + 1, size_ - 1);
+ }
+}
+
+bool zmq::trie_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;
+
+ trie_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::trie_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.
+ trie_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_--;
+ }
+}