haproxy/ebtree/eb32sctree.h

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/*
* Elastic Binary Trees - macros and structures for operations on 32bit nodes.
* Version 6.0.6 with backports from v7-dev
* (C) 2002-2017 - 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
*/
#ifndef _EB32SCTREE_H
#define _EB32SCTREE_H
#include "ebtree.h"
/* Return the structure of type <type> whose member <member> points to <ptr> */
#define eb32sc_entry(ptr, type, member) container_of(ptr, type, member)
/* These types may sometimes already be defined */
#ifndef _EB32TREE_H
typedef unsigned int u32;
typedef signed int s32;
#endif
/* This structure carries a node, a leaf, a scope, and a key. It must start
* with the eb_node so that it can be cast into an eb_node. We could also
* have put some sort of transparent union here to reduce the indirection
* level, but the fact is, the end user is not meant to manipulate internals,
* so this is pointless.
* In case sizeof(void*)>=sizeof(long), we know there will be some padding after
* the leaf if it's unaligned. In this case we force the alignment on void* so
* that we prefer to have the padding before for more efficient accesses.
*/
struct eb32sc_node {
struct eb_node node; /* the tree node, must be at the beginning */
MAYBE_ALIGN(sizeof(u32));
u32 key;
ALWAYS_ALIGN(sizeof(void*));
unsigned long node_s; /* visibility of this node's branches */
unsigned long leaf_s; /* visibility of this node's leaf */
} ALIGNED(sizeof(void*));
/*
* Exported functions and macros.
* Many of them are always inlined because they are extremely small, and
* are generally called at most once or twice in a program.
*/
/*
* The following functions are not inlined by default. They are declared
* in eb32sctree.c, which simply relies on their inline version.
*/
struct eb32sc_node *eb32sc_lookup_ge(struct eb_root *root, u32 x, unsigned long scope);
struct eb32sc_node *eb32sc_lookup_ge_or_first(struct eb_root *root, u32 x, unsigned long scope);
struct eb32sc_node *eb32sc_insert(struct eb_root *root, struct eb32sc_node *new, unsigned long scope);
void eb32sc_delete(struct eb32sc_node *node);
/* Walks down left starting at root pointer <start>, and follow the leftmost
* branch whose scope matches <scope>. It either returns the node hosting the
* first leaf on that side, or NULL if no leaf is found. <start> may either be
* NULL or a branch pointer. The pointer to the leaf (or NULL) is returned.
*/
static inline struct eb32sc_node *eb32sc_walk_down_left(eb_troot_t *start, unsigned long scope)
{
struct eb_root *root;
struct eb_node *node;
struct eb32sc_node *eb32;
if (unlikely(!start))
return NULL;
while (1) {
if (eb_gettag(start) == EB_NODE) {
root = eb_untag(start, EB_NODE);
node = eb_root_to_node(root);
eb32 = container_of(node, struct eb32sc_node, node);
if (eb32->node_s & scope) {
start = node->branches.b[EB_LEFT];
continue;
}
start = node->node_p;
}
else {
root = eb_untag(start, EB_LEAF);
node = eb_root_to_node(root);
eb32 = container_of(node, struct eb32sc_node, node);
if (eb32->leaf_s & scope)
return eb32;
start = node->leaf_p;
}
/* here we're on a node that doesn't match the scope. We have
* to walk to the closest right location.
*/
while (eb_gettag(start) != EB_LEFT)
/* Walking up from right branch, so we cannot be below root */
start = (eb_root_to_node(eb_untag(start, EB_RGHT)))->node_p;
/* Note that <start> cannot be NULL at this stage */
root = eb_untag(start, EB_LEFT);
start = root->b[EB_RGHT];
if (eb_clrtag(start) == NULL)
return NULL;
}
}
/* Return next node in the tree, starting with tagged parent <start>, or NULL if none */
static inline struct eb32sc_node *eb32sc_next_with_parent(eb_troot_t *start, unsigned long scope)
{
while (eb_gettag(start) != EB_LEFT)
/* Walking up from right branch, so we cannot be below root */
start = (eb_root_to_node(eb_untag(start, EB_RGHT)))->node_p;
/* Note that <t> cannot be NULL at this stage */
start = (eb_untag(start, EB_LEFT))->b[EB_RGHT];
if (eb_clrtag(start) == NULL)
return NULL;
return eb32sc_walk_down_left(start, scope);
}
/* Return next node in the tree, or NULL if none */
static inline struct eb32sc_node *eb32sc_next(struct eb32sc_node *eb32, unsigned long scope)
{
return eb32sc_next_with_parent(eb32->node.leaf_p, scope);
}
/* Return leftmost node in the tree, or NULL if none */
static inline struct eb32sc_node *eb32sc_first(struct eb_root *root, unsigned long scope)
{
return eb32sc_walk_down_left(root->b[0], scope);
}
#endif /* _EB32SC_TREE_H */