mirror of
https://github.com/zeromq/libzmq.git
synced 2025-01-22 07:29:31 +08:00
f0f16505e5
Copyrights had become ads for Sustrik's corporate sponsors, going against the original agreement to share copyrights with the community (that agreement was: one line stating iMatix copyright + one reference to AUTHORS file). The proliferation of corporate ads is also unfair to the many individual authors. I've removed ALL corporate title from the source files so the copyright statements can now be centralized in AUTHORS and source files can be properly updated on an annual basis.
336 lines
10 KiB
C++
336 lines
10 KiB
C++
/*
|
|
Copyright (c) 2007-2013 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),
|
|
live_nodes (0)
|
|
{
|
|
}
|
|
|
|
zmq::trie_t::~trie_t ()
|
|
{
|
|
if (count == 1) {
|
|
zmq_assert (next.node);
|
|
delete next.node;
|
|
next.node = 0;
|
|
}
|
|
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);
|
|
alloc_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;
|
|
alloc_assert (next.node);
|
|
++live_nodes;
|
|
zmq_assert (live_nodes == 1);
|
|
}
|
|
return next.node->add (prefix_ + 1, size_ - 1);
|
|
}
|
|
else {
|
|
if (!next.table [c - min]) {
|
|
next.table [c - min] = new (std::nothrow) trie_t;
|
|
alloc_assert (next.table [c - min]);
|
|
++live_nodes;
|
|
zmq_assert (live_nodes > 1);
|
|
}
|
|
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;
|
|
|
|
bool ret = next_node->rm (prefix_ + 1, size_ - 1);
|
|
|
|
// Prune redundant nodes
|
|
if (next_node->is_redundant ()) {
|
|
delete next_node;
|
|
zmq_assert (count > 0);
|
|
|
|
if (count == 1) {
|
|
// The just pruned node is was the only live node
|
|
next.node = 0;
|
|
count = 0;
|
|
--live_nodes;
|
|
zmq_assert (live_nodes == 0);
|
|
}
|
|
else {
|
|
next.table [c - min] = 0;
|
|
zmq_assert (live_nodes > 1);
|
|
--live_nodes;
|
|
|
|
// Compact the table if possible
|
|
if (live_nodes == 1) {
|
|
// We can switch to using the more compact single-node
|
|
// representation since the table only contains one live node
|
|
trie_t *node = 0;
|
|
// Since we always compact the table the pruned node must
|
|
// either be the left-most or right-most ptr in the node
|
|
// table
|
|
if (c == min) {
|
|
// The pruned node is the left-most node ptr in the
|
|
// node table => keep the right-most node
|
|
node = next.table [count - 1];
|
|
min += count - 1;
|
|
}
|
|
else
|
|
if (c == min + count - 1) {
|
|
// The pruned node is the right-most node ptr in the
|
|
// node table => keep the left-most node
|
|
node = next.table [0];
|
|
}
|
|
zmq_assert (node);
|
|
free (next.table);
|
|
next.node = node;
|
|
count = 1;
|
|
}
|
|
else
|
|
if (c == min) {
|
|
// We can compact the table "from the left".
|
|
// Find the left-most non-null node ptr, which we'll use as
|
|
// our new min
|
|
unsigned char new_min = min;
|
|
for (unsigned short i = 1; i < count; ++i) {
|
|
if (next.table [i]) {
|
|
new_min = i + min;
|
|
break;
|
|
}
|
|
}
|
|
zmq_assert (new_min != min);
|
|
|
|
trie_t **old_table = next.table;
|
|
zmq_assert (new_min > min);
|
|
zmq_assert (count > new_min - min);
|
|
|
|
count = count - (new_min - min);
|
|
next.table = (trie_t**) malloc (sizeof (trie_t*) * count);
|
|
alloc_assert (next.table);
|
|
|
|
memmove (next.table, old_table + (new_min - min),
|
|
sizeof (trie_t*) * count);
|
|
free (old_table);
|
|
|
|
min = new_min;
|
|
}
|
|
else
|
|
if (c == min + count - 1) {
|
|
// We can compact the table "from the right".
|
|
// Find the right-most non-null node ptr, which we'll use to
|
|
// determine the new table size
|
|
unsigned short new_count = count;
|
|
for (unsigned short i = 1; i < count; ++i) {
|
|
if (next.table [count - 1 - i]) {
|
|
new_count = count - i;
|
|
break;
|
|
}
|
|
}
|
|
zmq_assert (new_count != count);
|
|
count = new_count;
|
|
|
|
trie_t **old_table = next.table;
|
|
next.table = (trie_t**) malloc (sizeof (trie_t*) * count);
|
|
alloc_assert (next.table);
|
|
|
|
memmove (next.table, old_table, sizeof (trie_t*) * count);
|
|
free (old_table);
|
|
}
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
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 short c = 0; c != count; c++) {
|
|
(*buff_) [buffsize_] = min + c;
|
|
if (next.table [c])
|
|
next.table [c]->apply_helper (buff_, buffsize_ + 1, maxbuffsize_,
|
|
func_, arg_);
|
|
}
|
|
}
|
|
|
|
bool zmq::trie_t::is_redundant () const
|
|
{
|
|
return refcnt == 0 && live_nodes == 0;
|
|
}
|