hash/value.c

Go to the documentation of this file.

/**
 * \file
 *
 * \author  Georg Hopp
 *
 * \copyright
 * Copyright © 2012  Georg Hopp
 *
 * 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/>.
 */

#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>

#include "class.h"
#include "utils/hash.h"
#include "utils/memory.h"
#include "commons.h"

#include "hash/value.h"
#include "hash/interface/hashable.h"

static
int
hashValueCtor(void * _this, va_list * params)
{
    HashValue this = _this;
    char * key     = va_arg(* params, char*);
    void * value;
    
    this->nkey   = va_arg(* params, size_t);
    value        = va_arg(* params, void*);
    this->nvalue = va_arg(* params, size_t);

    this->key = memMalloc(this->nkey + 1);
    this->key[this->nkey] = 0;
    memcpy(this->key, key, this->nkey);

    this->hash = sdbm((unsigned char *)this->key, this->nkey);

    if (NULL != value) {
        this->value = memMalloc(this->nvalue + 1);
        ((char*)this->value)[this->nvalue] = 0;
        memcpy(this->value, value, this->nvalue);
    }

    return 0;
}

static
void
hashValueDtor(void * _this)
{
    HashValue this = _this;

    MEM_FREE(this->key);
    MEM_FREE(this->value);
}

static
unsigned long
hashValueGetHash(void * _this)
{
    HashValue this = _this;

    return this->hash;
}

static
void
hashValueHandleDouble(void * _this, void * _double)
{
    HashValue this = _this;
    HashValue doub = _double;
    void * tmp_value;
    size_t tmp_nvalue;

    /**
     * here we swap the internal data of both objects,
     * effectively overwriting the old entry. We need not
     * to free anything here as _double will be deleted
     * afterwards anyway (\see hash/add.c).
     */
    tmp_value   = this->value;
    this->value = doub->value;
    doub->value = tmp_value;

    tmp_nvalue   = this->nvalue;
    this->nvalue = doub->nvalue;
    doub->nvalue = tmp_nvalue;
}

INIT_IFACE(Class, hashValueCtor, hashValueDtor, NULL);
INIT_IFACE(Hashable, hashValueGetHash, hashValueHandleDouble);
CREATE_CLASS(HashValue, NULL, IFACE(Class), IFACE(Hashable));

// vim: set ts=4 sw=4: