haproxy/ebtree/ebpttree.c
Willy Tarreau 3a93244ed8 [MEDIUM] ebtree: upgrade to version 6.0
This version adds support for prefix-based matching of memory blocks,
as well as some code-size and performance improvements on the generic
code. It provides a prefix insertion and longest match which are
compatible with the rest of the common features (walk, duplicates,
delete, ...). This is typically used for network address matching. The
longest-match code is a bit slower than the original memory block
handling code, so they have not been merged together into generic
code. Still it's possible to perform about 10 million networks lookups
per second in a set of 50000, so this should be enough for most usages.

This version also fixes some bugs in parts that were not used, so there
is no need to backport them.
2010-05-12 16:52:00 +02:00

209 lines
6.8 KiB
C

/*
* Elastic Binary Trees - exported functions for operations on pointer nodes.
* Version 6.0
* (C) 2002-2010 - Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* Consult ebpttree.h for more details about those functions */
#include "ebpttree.h"
REGPRM2 struct ebpt_node *ebpt_insert(struct eb_root *root, struct ebpt_node *new)
{
return __ebpt_insert(root, new);
}
REGPRM2 struct ebpt_node *ebpt_lookup(struct eb_root *root, void *x)
{
return __ebpt_lookup(root, x);
}
/*
* Find the last occurrence of the highest key in the tree <root>, which is
* equal to or less than <x>. NULL is returned is no key matches.
*/
REGPRM2 struct ebpt_node *ebpt_lookup_le(struct eb_root *root, void *x)
{
struct ebpt_node *node;
eb_troot_t *troot;
troot = root->b[EB_LEFT];
if (unlikely(troot == NULL))
return NULL;
while (1) {
if ((eb_gettag(troot) == EB_LEAF)) {
/* We reached a leaf, which means that the whole upper
* parts were common. We will return either the current
* node or its next one if the former is too small.
*/
node = container_of(eb_untag(troot, EB_LEAF),
struct ebpt_node, node.branches);
if (node->key <= x)
return node;
/* return prev */
troot = node->node.leaf_p;
break;
}
node = container_of(eb_untag(troot, EB_NODE),
struct ebpt_node, node.branches);
if (node->node.bit < 0) {
/* We're at the top of a dup tree. Either we got a
* matching value and we return the rightmost node, or
* we don't and we skip the whole subtree to return the
* prev node before the subtree. Note that since we're
* at the top of the dup tree, we can simply return the
* prev node without first trying to escape from the
* tree.
*/
if (node->key <= x) {
troot = node->node.branches.b[EB_RGHT];
while (eb_gettag(troot) != EB_LEAF)
troot = (eb_untag(troot, EB_NODE))->b[EB_RGHT];
return container_of(eb_untag(troot, EB_LEAF),
struct ebpt_node, node.branches);
}
/* return prev */
troot = node->node.node_p;
break;
}
if ((((ptr_t)x ^ (ptr_t)node->key) >> node->node.bit) >= EB_NODE_BRANCHES) {
/* No more common bits at all. Either this node is too
* small and we need to get its highest value, or it is
* too large, and we need to get the prev value.
*/
if (((ptr_t)node->key >> node->node.bit) < ((ptr_t)x >> node->node.bit)) {
troot = node->node.branches.b[EB_RGHT];
return ebpt_entry(eb_walk_down(troot, EB_RGHT), struct ebpt_node, node);
}
/* Further values will be too high here, so return the prev
* unique node (if it exists).
*/
troot = node->node.node_p;
break;
}
troot = node->node.branches.b[((ptr_t)x >> node->node.bit) & EB_NODE_BRANCH_MASK];
}
/* If we get here, it means we want to report previous node before the
* current one which is not above. <troot> is already initialised to
* the parent's branches.
*/
while (eb_gettag(troot) == EB_LEFT) {
/* Walking up from left branch. We must ensure that we never
* walk beyond root.
*/
if (unlikely(eb_clrtag((eb_untag(troot, EB_LEFT))->b[EB_RGHT]) == NULL))
return NULL;
troot = (eb_root_to_node(eb_untag(troot, EB_LEFT)))->node_p;
}
/* Note that <troot> cannot be NULL at this stage */
troot = (eb_untag(troot, EB_RGHT))->b[EB_LEFT];
node = ebpt_entry(eb_walk_down(troot, EB_RGHT), struct ebpt_node, node);
return node;
}
/*
* Find the first occurrence of the lowest key in the tree <root>, which is
* equal to or greater than <x>. NULL is returned is no key matches.
*/
REGPRM2 struct ebpt_node *ebpt_lookup_ge(struct eb_root *root, void *x)
{
struct ebpt_node *node;
eb_troot_t *troot;
troot = root->b[EB_LEFT];
if (unlikely(troot == NULL))
return NULL;
while (1) {
if ((eb_gettag(troot) == EB_LEAF)) {
/* We reached a leaf, which means that the whole upper
* parts were common. We will return either the current
* node or its next one if the former is too small.
*/
node = container_of(eb_untag(troot, EB_LEAF),
struct ebpt_node, node.branches);
if (node->key >= x)
return node;
/* return next */
troot = node->node.leaf_p;
break;
}
node = container_of(eb_untag(troot, EB_NODE),
struct ebpt_node, node.branches);
if (node->node.bit < 0) {
/* We're at the top of a dup tree. Either we got a
* matching value and we return the leftmost node, or
* we don't and we skip the whole subtree to return the
* next node after the subtree. Note that since we're
* at the top of the dup tree, we can simply return the
* next node without first trying to escape from the
* tree.
*/
if (node->key >= x) {
troot = node->node.branches.b[EB_LEFT];
while (eb_gettag(troot) != EB_LEAF)
troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
return container_of(eb_untag(troot, EB_LEAF),
struct ebpt_node, node.branches);
}
/* return next */
troot = node->node.node_p;
break;
}
if ((((ptr_t)x ^ (ptr_t)node->key) >> node->node.bit) >= EB_NODE_BRANCHES) {
/* No more common bits at all. Either this node is too
* large and we need to get its lowest value, or it is too
* small, and we need to get the next value.
*/
if (((ptr_t)node->key >> node->node.bit) > ((ptr_t)x >> node->node.bit)) {
troot = node->node.branches.b[EB_LEFT];
return ebpt_entry(eb_walk_down(troot, EB_LEFT), struct ebpt_node, node);
}
/* Further values will be too low here, so return the next
* unique node (if it exists).
*/
troot = node->node.node_p;
break;
}
troot = node->node.branches.b[((ptr_t)x >> node->node.bit) & EB_NODE_BRANCH_MASK];
}
/* If we get here, it means we want to report next node after the
* current one which is not below. <troot> is already initialised
* to the parent's branches.
*/
while (eb_gettag(troot) != EB_LEFT)
/* Walking up from right branch, so we cannot be below root */
troot = (eb_root_to_node(eb_untag(troot, EB_RGHT)))->node_p;
/* Note that <troot> cannot be NULL at this stage */
troot = (eb_untag(troot, EB_LEFT))->b[EB_RGHT];
if (eb_clrtag(troot) == NULL)
return NULL;
node = ebpt_entry(eb_walk_down(troot, EB_LEFT), struct ebpt_node, node);
return node;
}