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/*
* Copyright (c) 2011-2018 Richard Braun.
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
* Upstream site with license notes :
* http://git.sceen.net/rbraun/librbraun.git/
*
*
* Radix tree.
*
* In addition to the standard insertion operation, this implementation can
* allocate keys for the caller at insertion time. It also allows lookups to
* occur concurrently with updates using RCU.
*/
#ifndef KERN_RDXTREE_H
#define KERN_RDXTREE_H
#include <assert.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <kern/init.h>
#include <kern/rcu.h>
typedef uint64_t rdxtree_key_t;
/*
* Radix tree initialization flags.
*/
#define RDXTREE_KEY_ALLOC 0x1 /* Enable key allocation */
/*
* Radix tree.
*/
struct rdxtree;
/*
* Radix tree iterator.
*/
struct rdxtree_iter;
/*
* Static tree initializer.
*/
#define RDXTREE_INITIALIZER { 0, NULL }
#include <kern/rdxtree_i.h>
/*
* Initialize a tree.
*/
static inline void
rdxtree_init(struct rdxtree *tree, unsigned short flags)
{
assert((flags & ~RDXTREE_KEY_ALLOC) == 0);
tree->height = 0;
tree->flags = flags;
tree->root = NULL;
}
/*
* Insert a pointer in a tree.
*
* The ptr parameter must not be NULL.
*/
static inline int
rdxtree_insert(struct rdxtree *tree, rdxtree_key_t key, void *ptr)
{
return rdxtree_insert_common(tree, key, ptr, NULL);
}
/*
* Insert a pointer in a tree and obtain its slot.
*
* The ptr and slotp parameters must not be NULL. If successful, the slot of
* the newly inserted pointer is stored at the address pointed to by the slotp
* parameter.
*/
static inline int
rdxtree_insert_slot(struct rdxtree *tree, rdxtree_key_t key,
void *ptr, void ***slotp)
{
return rdxtree_insert_common(tree, key, ptr, slotp);
}
/*
* Insert a pointer in a tree, for which a new key is allocated.
*
* The ptr and keyp parameters must not be NULL. The newly allocated key is
* stored at the address pointed to by the keyp parameter.
*/
static inline int
rdxtree_insert_alloc(struct rdxtree *tree, void *ptr, rdxtree_key_t *keyp)
{
return rdxtree_insert_alloc_common(tree, ptr, keyp, NULL);
}
/*
* Insert a pointer in a tree, for which a new key is allocated, and obtain
* its slot.
*
* The ptr, keyp and slotp parameters must not be NULL. The newly allocated
* key is stored at the address pointed to by the keyp parameter while the
* slot of the inserted pointer is stored at the address pointed to by the
* slotp parameter.
*/
static inline int
rdxtree_insert_alloc_slot(struct rdxtree *tree, void *ptr,
rdxtree_key_t *keyp, void ***slotp)
{
return rdxtree_insert_alloc_common(tree, ptr, keyp, slotp);
}
/*
* Remove a pointer from a tree.
*
* The matching pointer is returned if successful, NULL otherwise.
*/
void * rdxtree_remove(struct rdxtree *tree, rdxtree_key_t key);
/*
* Look up a pointer in a tree.
*
* The matching pointer is returned if successful, NULL otherwise.
*/
static inline void *
rdxtree_lookup(const struct rdxtree *tree, rdxtree_key_t key)
{
return rdxtree_lookup_common(tree, key, false);
}
/*
* Look up a slot in a tree.
*
* A slot is a pointer to a stored pointer in a tree. It can be used as
* a placeholder for fast replacements to avoid multiple lookups on the same
* key.
*
* A slot for the matching pointer is returned if successful, NULL otherwise.
*
* See rdxtree_replace_slot().
*/
static inline void **
rdxtree_lookup_slot(const struct rdxtree *tree, rdxtree_key_t key)
{
return rdxtree_lookup_common(tree, key, true);
}
static inline void *
rdxtree_load_slot(void **slot)
{
return rcu_load_ptr(*slot);
}
/*
* Replace a pointer in a tree.
*
* The ptr parameter must not be NULL. The previous pointer is returned.
*
* See rdxtree_lookup_slot().
*/
void * rdxtree_replace_slot(void **slot, void *ptr);
/*
* Forge a loop to process all pointers of a tree.
*
* It is not safe to modify a tree from such a loop.
*/
#define rdxtree_for_each(tree, iter, ptr) \
for (rdxtree_iter_init(iter), ptr = rdxtree_walk(tree, iter); \
ptr != NULL; \
ptr = rdxtree_walk(tree, iter))
/*
* Return the key of the current pointer from an iterator.
*/
static inline rdxtree_key_t
rdxtree_iter_key(const struct rdxtree_iter *iter)
{
return iter->key;
}
/*
* Remove all pointers from a tree.
*
* The common way to destroy a tree and its pointers is to loop over all
* the pointers using rdxtree_for_each(), freeing them, then call this
* function.
*/
void rdxtree_remove_all(struct rdxtree *tree);
/*
* This init operation provides :
* - module fully initialized
*/
INIT_OP_DECLARE(rdxtree_setup);
#endif /* KERN_RDXTREE_H */
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