OSSP CVS Repository

ossp-pkg/act/act_hash.c 1.6

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/* 
**  Act - Abstract Container Type Library
**  Copyright (c) 1999-2001 Ralf S. Engelschall <rse@engelschall.com>
**
**  This file is part of Act, a library for dealing with Abstract 
**  Container Types which can be found at http://www.ossp.org/pkg/act/.
**
**  Permission to use, copy, modify, and distribute this software for
**  any purpose with or without fee is hereby granted, provided that
**  the above copyright notice and this permission notice appear in all
**  copies.
**
**  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 AUTHORS AND COPYRIGHT HOLDERS AND THEIR
**  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.
**
**  act_hash.c: dynamic hash table API (implementation)
*/

#include "act_p.h"

/* the generic top-level data structure for a hash */
struct act_hash_st {
    act_ctx_t         *h_ctx;    /* the attached ACT context */
    act_hash_method_t *h_method; /* the hashing method which is actually used */
    void              *h_data;   /* the data structure of the hasing method */
};

/* convinience macro for calling a method */
#define method(h,name) h->h_method->m_##name

/* global initialization at library startup time */
intern int act_hash_init(void)
{
    act_ctx_set(act_ctx_default, ACT_HASH_METHOD,      act_hash_mth(lh));
    act_ctx_set(act_ctx_default, ACT_HASH_FUNC,        act_hash_fct(djbx33a));
    act_ctx_set(act_ctx_default, ACT_HASH_TABLESIZE,   128);
    act_ctx_set(act_ctx_default, ACT_HASH_MINLOADFCTR, 1);
    act_ctx_set(act_ctx_default, ACT_HASH_MAXLOADFCTR, 2);
    return TRUE;
}

/* global destruction at library startup time */
intern int act_hash_kill(void)
{
    return TRUE;
}

/* create a new hash */
act_hash_t *act_hash_new(act_ctx_t *ctx)
{
    act_hash_t *h;
    act_hash_method_t *method;
    void *data;

    insist(ctx != NULL, NULL);

    /* fetch the implementation method */
    insist(act_ctx_get(ctx, ACT_HASH_METHOD, &method), NULL);
    insist(method != NULL, NULL);
    insist(method->m_tag == ACT_HASH_METHOD_TAG, NULL);

    /* create a new hash */
    data = method->m_new(ctx);
    insist(data != NULL, NULL);

    /* allocate a top-level data structure */
    if ((h = (act_hash_t *)act_mem_alloc_ctx(ctx, sizeof(act_hash_t))) == NULL) {
        method->m_free(ctx, data);
        return NULL;
    }

    /* stash ingredients into top-level data structure */
    h->h_ctx    = act_ctx_dup(ctx, NULL);
    h->h_method = method;
    h->h_data   = data;

    return h;
}

/* return the attached context */
act_ctx_t *act_hash_ctx(act_hash_t *h)
{
    insist(h != NULL, NULL);
    return h->h_ctx;
}

/* destroy the hash */
int act_hash_free(act_hash_t *h)
{
    insist(h != NULL, NULL);

    /* destroy real hash table */
    if (!method(h, free)(h->h_ctx, h->h_data))
        return FALSE;

    /* destroy top-level structure */
    act_mem_free(h);

    return TRUE;
}

/* insert an element into the hash */
int act_hash_insert(act_hash_t *h, void *kp, int ks, void *dp, int ds, int ov)
{
    insist(h != NULL, NULL);
    return method(h, insert)(h->h_ctx, h->h_data, kp, ks, dp, ds, ov);
}

/* lookup an element from the hash */
int act_hash_lookup(act_hash_t *h, void *kp, int ks, void **dp, int *ds)
{
    insist(h != NULL, NULL);
    return method(h, lookup)(h->h_ctx, h->h_data, kp, ks, dp, ds);
}

/* delete an element in the hash */
int act_hash_delete(act_hash_t *h, void *kp, int ks)
{
    insist(h != NULL, NULL);
    return method(h, delete)(h->h_ctx, h->h_data, kp, ks);
}

/* determine byte and element size of the hash */
int act_hash_size(act_hash_t *h, long *pb, long *pe)
{
    insist(h != NULL, NULL);
    insist(pb != NULL, NULL);
    insist(pe != NULL, NULL);
    return method(h, size)(h->h_ctx, h->h_data, pb, pe);
}

/* return summary of current internal status */
int act_hash_status(act_hash_t *h, char *ps, int ns)
{
    insist(h != NULL, NULL);
    insist(ps != NULL, NULL);
    insist(ns > 0, NULL);
    return method(h, status)(h->h_ctx, h->h_data, ps, ns);
}

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