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/*
Copyright (c) 2007-2011 iMatix Corporation
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 <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 short i = 0; i != count; ++i)
if (next.table [i])
delete next.table [i];
free (next.table);
}
}
bool 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 refcnt == 1;
}
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 short 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 short 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 short i = old_count; i != count; i++)
next.table [i] = NULL;
}
else {
// The new character is below the current character range.
unsigned short 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 short 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);
}
return 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]);
}
return next.table [c - min]->add (prefix_ + 1, size_ - 1);
}
}
bool zmq::trie_t::rm (unsigned char *prefix_, size_t size_)
{
// TODO: Shouldn't an error be reported if the key does not exist?
if (!size_) {
if (!refcnt)
return false;
refcnt--;
return refcnt == 0;
}
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_--;
}
}
void zmq::trie_t::apply (void (*func_) (unsigned char *data_, size_t size_,
void *arg_), void *arg_)
{
unsigned char *buff = NULL;
apply_helper (&buff, 0, 0, func_, arg_);
free (buff);
}
void zmq::trie_t::apply_helper (
unsigned char **buff_, size_t buffsize_, size_t maxbuffsize_,
void (*func_) (unsigned char *data_, size_t size_, void *arg_), void *arg_)
{
// If this node is a subscription, apply the function.
if (refcnt)
func_ (*buff_, buffsize_, arg_);
// Adjust the buffer.
if (buffsize_ >= maxbuffsize_) {
maxbuffsize_ = buffsize_ + 256;
*buff_ = (unsigned char*) realloc (*buff_, maxbuffsize_);
zmq_assert (*buff_);
}
// If there are no subnodes in the trie, return.
if (count == 0)
return;
// If there's one subnode (optimisation).
if (count == 1) {
(*buff_) [buffsize_] = min;
buffsize_++;
next.node->apply_helper (buff_, buffsize_, maxbuffsize_, func_, arg_);
return;
}
// If there are multiple subnodes.
for (unsigned char c = 0; c != count; c++) {
(*buff_) [buffsize_] = min + c;
if (next.table [c])
next.table [c]->apply_helper (buff_, buffsize_ + 1, maxbuffsize_,
func_, arg_);
}
}
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