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/*
* librd - Rapid Development C library
*
* Copyright (c) 2012-2016, Magnus Edenhill
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* AVL tree.
* Inspired by Ian Piumarta's tree.h implementation.
*/
#ifndef _RDAVL_H_
#define _RDAVL_H_
#include "tinycthread.h"
typedef enum {
RD_AVL_LEFT,
RD_AVL_RIGHT,
} rd_avl_dir_t;
/**
* AVL tree node.
* Add 'rd_avl_node_t ..' as field to your element's struct and
* provide it as the 'field' argument in the API below.
*/
typedef struct rd_avl_node_s {
struct rd_avl_node_s *ran_p[2]; /* RD_AVL_LEFT and RD_AVL_RIGHT */
int ran_height; /* Sub-tree height */
void *ran_elm; /* Backpointer to the containing
* element. This could be considered
* costly but is convenient for the
* caller: RAM is cheap,
* development time isn't*/
} rd_avl_node_t;
/**
* Per-AVL application-provided element comparator.
*/
typedef int (*rd_avl_cmp_t)(const void *, const void *);
/**
* AVL tree
*/
typedef struct rd_avl_s {
rd_avl_node_t *ravl_root; /* Root node */
rd_avl_cmp_t ravl_cmp; /* Comparator */
int ravl_flags; /* Flags */
#define RD_AVL_F_LOCKS 0x1 /* Enable thread-safeness */
#define RD_AVL_F_OWNER 0x2 /* internal: rd_avl_init() allocated ravl */
rwlock_t ravl_rwlock; /* Mutex when .._F_LOCKS is set. */
} rd_avl_t;
/**
*
*
* Public API
*
*
*/
/**
* Insert 'elm' into AVL tree.
* In case of collision the previous entry is overwritten by the
* new one and the previous element is returned, else NULL.
*/
#define RD_AVL_INSERT(ravl, elm, field) rd_avl_insert(ravl, elm, &(elm)->field)
/**
* Remove element by matching value 'elm' using compare function.
*/
#define RD_AVL_REMOVE_ELM(ravl, elm) rd_avl_remove_elm(ravl, elm)
/**
* Search for (by value using compare function) and return matching elm.
*/
#define RD_AVL_FIND(ravl, elm) rd_avl_find(ravl, elm, 1)
/**
* Search (by value using compare function) for and return matching elm.
* Same as RD_AVL_FIND_NL() but assumes 'ravl' ís already locked
* by 'rd_avl_*lock()'.
*
* NOTE: rd_avl_wrlock() must be held.
*/
#define RD_AVL_FIND_NL(ravl, elm) \
rd_avl_find_node(ravl, (ravl)->ravl_root, elm, 0)
/**
* Search (by value using compare function) for elm and return its AVL node.
*
* NOTE: rd_avl_wrlock() must be held.
*/
#define RD_AVL_FIND_NODE_NL(ravl, elm) rd_avl_find(ravl, elm, 0)
/**
* Changes the element pointer for an existing AVL node in the tree.
* The new element must be identical (according to the comparator)
* to the previous element.
*
* NOTE: rd_avl_wrlock() must be held.
*/
#define RD_AVL_ELM_SET_NL(ran, elm) ((ran)->ran_elm = (elm))
/**
* Returns the current element pointer for an existing AVL node in the tree
*
* NOTE: rd_avl_*lock() must be held.
*/
#define RD_AVL_ELM_GET_NL(ran) ((ran)->ran_elm)
/**
* Destroy previously initialized (by rd_avl_init()) AVL tree.
*/
void rd_avl_destroy(rd_avl_t *ravl);
/**
* Initialize (and optionally allocate if 'ravl' is NULL) AVL tree.
* 'cmp' is the comparison function that takes two const pointers
* pointing to the elements being compared (rather than the avl_nodes).
* 'flags' is zero or more of the RD_AVL_F_.. flags.
*
* For thread-safe AVL trees supply RD_AVL_F_LOCKS in 'flags'.
*/
rd_avl_t *rd_avl_init(rd_avl_t *ravl, rd_avl_cmp_t cmp, int flags);
/**
* 'ravl' locking functions.
* Locking is performed automatically for all methods except for
* those with the "_NL"/"_nl" suffix ("not locked") which expects
* either read or write lock to be held.
*
* rdavl utilizes rwlocks to allow multiple concurrent read threads.
*/
static RD_INLINE RD_UNUSED void rd_avl_rdlock(rd_avl_t *ravl) {
if (ravl->ravl_flags & RD_AVL_F_LOCKS)
rwlock_rdlock(&ravl->ravl_rwlock);
}
static RD_INLINE RD_UNUSED void rd_avl_wrlock(rd_avl_t *ravl) {
if (ravl->ravl_flags & RD_AVL_F_LOCKS)
rwlock_wrlock(&ravl->ravl_rwlock);
}
static RD_INLINE RD_UNUSED void rd_avl_rdunlock(rd_avl_t *ravl) {
if (ravl->ravl_flags & RD_AVL_F_LOCKS)
rwlock_rdunlock(&ravl->ravl_rwlock);
}
static RD_INLINE RD_UNUSED void rd_avl_wrunlock(rd_avl_t *ravl) {
if (ravl->ravl_flags & RD_AVL_F_LOCKS)
rwlock_wrunlock(&ravl->ravl_rwlock);
}
/**
* Private API, dont use directly.
*/
rd_avl_node_t *rd_avl_insert_node(rd_avl_t *ravl,
rd_avl_node_t *parent,
rd_avl_node_t *ran,
rd_avl_node_t **existing);
static RD_UNUSED void *
rd_avl_insert(rd_avl_t *ravl, void *elm, rd_avl_node_t *ran) {
rd_avl_node_t *existing = NULL;
memset(ran, 0, sizeof(*ran));
ran->ran_elm = elm;
rd_avl_wrlock(ravl);
ravl->ravl_root =
rd_avl_insert_node(ravl, ravl->ravl_root, ran, &existing);
rd_avl_wrunlock(ravl);
return existing ? existing->ran_elm : NULL;
}
rd_avl_node_t *
rd_avl_remove_elm0(rd_avl_t *ravl, rd_avl_node_t *parent, const void *elm);
static RD_INLINE RD_UNUSED void rd_avl_remove_elm(rd_avl_t *ravl,
const void *elm) {
rd_avl_wrlock(ravl);
ravl->ravl_root = rd_avl_remove_elm0(ravl, ravl->ravl_root, elm);
rd_avl_wrunlock(ravl);
}
rd_avl_node_t *rd_avl_find_node(const rd_avl_t *ravl,
const rd_avl_node_t *begin,
const void *elm);
static RD_INLINE RD_UNUSED void *
rd_avl_find(rd_avl_t *ravl, const void *elm, int dolock) {
const rd_avl_node_t *ran;
void *ret;
if (dolock)
rd_avl_rdlock(ravl);
ran = rd_avl_find_node(ravl, ravl->ravl_root, elm);
ret = ran ? ran->ran_elm : NULL;
if (dolock)
rd_avl_rdunlock(ravl);
return ret;
}
#endif /* _RDAVL_H_ */
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