tommyhashlin.h

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/*
 * Copyright (c) 2010, Andrea Mazzoleni. 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.
 */

#ifndef __TOMMYHASHLIN_H
#define __TOMMYHASHLIN_H

#include "tommyhash.h"

/******************************************************************************/
/* hashlin */

#define TOMMY_HASHLIN_BIT 6

typedef tommy_node tommy_hashlin_node;

#define TOMMY_HASHLIN_BIT_MAX 32

typedef struct tommy_hashlin_struct {
        tommy_hashlin_node** bucket[TOMMY_HASHLIN_BIT_MAX]; 
        tommy_uint_t bucket_bit; 
        tommy_count_t bucket_max; 
        tommy_count_t bucket_mask; 
        tommy_count_t low_max; 
        tommy_count_t low_mask; 
        tommy_count_t split; 
        tommy_count_t count; 
        tommy_uint_t state; 
} tommy_hashlin;

void tommy_hashlin_init(tommy_hashlin* hashlin);

void tommy_hashlin_done(tommy_hashlin* hashlin);

void tommy_hashlin_insert(tommy_hashlin* hashlin, tommy_hashlin_node* node, void* data, tommy_hash_t hash);

void* tommy_hashlin_remove(tommy_hashlin* hashlin, tommy_search_func* cmp, const void* cmp_arg, tommy_hash_t hash);

tommy_inline tommy_hashlin_node** tommy_hashlin_pos(tommy_hashlin* hashlin, tommy_hash_t pos)
{
        tommy_uint_t bsr;

        /* get the highest bit set, in case of all 0, return 0 */
        bsr = tommy_ilog2_u32(pos | 1);

        return &hashlin->bucket[bsr][pos];
}

tommy_inline tommy_hashlin_node** tommy_hashlin_bucket_ref(tommy_hashlin* hashlin, tommy_hash_t hash)
{
        tommy_count_t pos;
        tommy_count_t high_pos;

        pos = hash & hashlin->low_mask;
        high_pos = hash & hashlin->bucket_mask;

        /* if this position is already allocated in the high half */
        if (pos < hashlin->split) {
                /* The following assigment is expected to be implemented */
                /* with a conditional move instruction */
                /* that results in a little better and constant performance */
                /* regardless of the split position. */
                /* This affects mostly the worst case, when the split value */
                /* is near at its half, resulting in a totally unpredictable */
                /* condition by the CPU. */
                /* In such case the use of the conditional move is generally faster. */

                /* use also the high bit */
                pos = high_pos;
        }

        return tommy_hashlin_pos(hashlin, pos);
}

tommy_inline tommy_hashlin_node* tommy_hashlin_bucket(tommy_hashlin* hashlin, tommy_hash_t hash)
{
        return *tommy_hashlin_bucket_ref(hashlin, hash);
}

tommy_inline void* tommy_hashlin_search(tommy_hashlin* hashlin, tommy_search_func* cmp, const void* cmp_arg, tommy_hash_t hash)
{
        tommy_hashlin_node* i = tommy_hashlin_bucket(hashlin, hash);

        while (i) {
                /* we first check if the hash matches, as in the same bucket we may have multiples hash values */
                if (i->key == hash && cmp(cmp_arg, i->data) == 0)
                        return i->data;
                i = i->next;
        }
        return 0;
}

void* tommy_hashlin_remove_existing(tommy_hashlin* hashlin, tommy_hashlin_node* node);

void tommy_hashlin_foreach(tommy_hashlin* hashlin, tommy_foreach_func* func);

void tommy_hashlin_foreach_arg(tommy_hashlin* hashlin, tommy_foreach_arg_func* func, void* arg);

tommy_inline tommy_count_t tommy_hashlin_count(tommy_hashlin* hashlin)
{
        return hashlin->count;
}

tommy_size_t tommy_hashlin_memory_usage(tommy_hashlin* hashlin);

#endif