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/*
* Elastic Binary Trees - exported functions for operations on pointer nodes.
* Version 6.0.6
* (C) 2002-2011 - Willy Tarreau <w@1wt.eu>
*
* This library 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, version 2.1
* exclusively.
*
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* Consult ebpttree.h for more details about those functions */
#include <import/ebpttree.h>
struct ebpt_node *ebpt_insert(struct eb_root *root, struct ebpt_node *new)
{
return __ebpt_insert(root, new);
}
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.
*/
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.
*/
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;
}
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