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03e7853581
This used to be a minor optimization on ix86 where registers are scarce and the calling convention not very efficient, but this platform is not relevant enough anymore to warrant all this dirt in the code for the sake of saving 1 or 2% of performance. Modern platforms don't use this at all since their calling convention already defaults to using several registers so better get rid of this once for all.
219 lines
6.9 KiB
C
219 lines
6.9 KiB
C
/*
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* Elastic Binary Trees - exported functions for operations on 32bit nodes.
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* Version 6.0.6
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* (C) 2002-2011 - Willy Tarreau <w@1wt.eu>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, version 2.1
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* exclusively.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/* Consult eb32tree.h for more details about those functions */
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#include "eb32tree.h"
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struct eb32_node *eb32_insert(struct eb_root *root, struct eb32_node *new)
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{
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return __eb32_insert(root, new);
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}
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struct eb32_node *eb32i_insert(struct eb_root *root, struct eb32_node *new)
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{
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return __eb32i_insert(root, new);
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}
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struct eb32_node *eb32_lookup(struct eb_root *root, u32 x)
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{
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return __eb32_lookup(root, x);
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}
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struct eb32_node *eb32i_lookup(struct eb_root *root, s32 x)
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{
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return __eb32i_lookup(root, x);
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}
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/*
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* Find the last occurrence of the highest key in the tree <root>, which is
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* equal to or less than <x>. NULL is returned is no key matches.
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*/
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struct eb32_node *eb32_lookup_le(struct eb_root *root, u32 x)
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{
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struct eb32_node *node;
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eb_troot_t *troot;
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troot = root->b[EB_LEFT];
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if (unlikely(troot == NULL))
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return NULL;
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while (1) {
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if ((eb_gettag(troot) == EB_LEAF)) {
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/* We reached a leaf, which means that the whole upper
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* parts were common. We will return either the current
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* node or its next one if the former is too small.
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*/
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node = container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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if (node->key <= x)
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return node;
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/* return prev */
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troot = node->node.leaf_p;
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break;
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}
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node = container_of(eb_untag(troot, EB_NODE),
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struct eb32_node, node.branches);
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if (node->node.bit < 0) {
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/* We're at the top of a dup tree. Either we got a
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* matching value and we return the rightmost node, or
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* we don't and we skip the whole subtree to return the
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* prev node before the subtree. Note that since we're
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* at the top of the dup tree, we can simply return the
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* prev node without first trying to escape from the
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* tree.
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*/
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if (node->key <= x) {
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troot = node->node.branches.b[EB_RGHT];
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while (eb_gettag(troot) != EB_LEAF)
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troot = (eb_untag(troot, EB_NODE))->b[EB_RGHT];
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return container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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}
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/* return prev */
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troot = node->node.node_p;
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break;
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}
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if (((x ^ node->key) >> node->node.bit) >= EB_NODE_BRANCHES) {
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/* No more common bits at all. Either this node is too
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* small and we need to get its highest value, or it is
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* too large, and we need to get the prev value.
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*/
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if ((node->key >> node->node.bit) < (x >> node->node.bit)) {
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troot = node->node.branches.b[EB_RGHT];
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return eb32_entry(eb_walk_down(troot, EB_RGHT), struct eb32_node, node);
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}
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/* Further values will be too high here, so return the prev
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* unique node (if it exists).
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*/
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troot = node->node.node_p;
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break;
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}
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troot = node->node.branches.b[(x >> node->node.bit) & EB_NODE_BRANCH_MASK];
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}
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/* If we get here, it means we want to report previous node before the
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* current one which is not above. <troot> is already initialised to
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* the parent's branches.
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*/
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while (eb_gettag(troot) == EB_LEFT) {
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/* Walking up from left branch. We must ensure that we never
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* walk beyond root.
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*/
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if (unlikely(eb_clrtag((eb_untag(troot, EB_LEFT))->b[EB_RGHT]) == NULL))
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return NULL;
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troot = (eb_root_to_node(eb_untag(troot, EB_LEFT)))->node_p;
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}
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/* Note that <troot> cannot be NULL at this stage */
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troot = (eb_untag(troot, EB_RGHT))->b[EB_LEFT];
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node = eb32_entry(eb_walk_down(troot, EB_RGHT), struct eb32_node, node);
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return node;
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}
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/*
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* Find the first occurrence of the lowest key in the tree <root>, which is
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* equal to or greater than <x>. NULL is returned is no key matches.
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*/
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struct eb32_node *eb32_lookup_ge(struct eb_root *root, u32 x)
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{
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struct eb32_node *node;
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eb_troot_t *troot;
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troot = root->b[EB_LEFT];
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if (unlikely(troot == NULL))
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return NULL;
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while (1) {
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if ((eb_gettag(troot) == EB_LEAF)) {
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/* We reached a leaf, which means that the whole upper
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* parts were common. We will return either the current
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* node or its next one if the former is too small.
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*/
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node = container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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if (node->key >= x)
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return node;
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/* return next */
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troot = node->node.leaf_p;
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break;
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}
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node = container_of(eb_untag(troot, EB_NODE),
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struct eb32_node, node.branches);
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if (node->node.bit < 0) {
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/* We're at the top of a dup tree. Either we got a
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* matching value and we return the leftmost node, or
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* we don't and we skip the whole subtree to return the
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* next node after the subtree. Note that since we're
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* at the top of the dup tree, we can simply return the
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* next node without first trying to escape from the
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* tree.
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*/
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if (node->key >= x) {
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troot = node->node.branches.b[EB_LEFT];
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while (eb_gettag(troot) != EB_LEAF)
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troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
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return container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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}
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/* return next */
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troot = node->node.node_p;
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break;
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}
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if (((x ^ node->key) >> node->node.bit) >= EB_NODE_BRANCHES) {
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/* No more common bits at all. Either this node is too
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* large and we need to get its lowest value, or it is too
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* small, and we need to get the next value.
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*/
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if ((node->key >> node->node.bit) > (x >> node->node.bit)) {
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troot = node->node.branches.b[EB_LEFT];
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return eb32_entry(eb_walk_down(troot, EB_LEFT), struct eb32_node, node);
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}
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/* Further values will be too low here, so return the next
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* unique node (if it exists).
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*/
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troot = node->node.node_p;
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break;
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}
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troot = node->node.branches.b[(x >> node->node.bit) & EB_NODE_BRANCH_MASK];
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}
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/* If we get here, it means we want to report next node after the
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* current one which is not below. <troot> is already initialised
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* to the parent's branches.
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*/
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while (eb_gettag(troot) != EB_LEFT)
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/* Walking up from right branch, so we cannot be below root */
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troot = (eb_root_to_node(eb_untag(troot, EB_RGHT)))->node_p;
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/* Note that <troot> cannot be NULL at this stage */
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troot = (eb_untag(troot, EB_LEFT))->b[EB_RGHT];
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if (eb_clrtag(troot) == NULL)
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return NULL;
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node = eb32_entry(eb_walk_down(troot, EB_LEFT), struct eb32_node, node);
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return node;
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}
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