/*  pdnmesh - a 2D finite element solver
    Copyright (C) 2001-2005 Sarod Yatawatta <sarod@users.sf.net>  
  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 2 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, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  $Id: hash.c,v 1.23 2005/02/22 03:26:01 sarod Exp $
*/


/* generic hash table */
#include "types.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h> /* for memset() */

/* initialize hash table */
void
htbl_init(htbl *tbl, int hashtable_size, size_t datasize, unsigned int (*h)(const void *key),
          int (*match)(const void *key1, const void *key2),
          void (*destroy)(void *data)) {
  int i;
  if (((tbl)->table = (glist*)malloc(hashtable_size*sizeof(glist))) == NULL ) {
    fprintf(stderr,"%s: %d: no free memory\n",__FILE__,__LINE__);
    exit(1);
  }

  tbl->positions=hashtable_size;
  tbl->size=0;
  for (i=0; i<tbl->positions; i++) {
   glist_sorted_init(&(tbl->table[i]),datasize,destroy,match);
  }

  tbl->h=h;
  tbl->destroy=destroy;
  tbl->match=match;
}


/* destroy hash table */
void
htbl_destroy(htbl* tbl) {
  int i;
  for (i=0; i<tbl->positions; i++) {
    glist_delete(&(tbl->table[i]));
  }
  free(tbl->table);
  memset(tbl,0,sizeof(htbl));
}


/* insert data */
/* if data inserted return 0, else return 1 (data already there) */
int
htbl_insert(htbl *tbl, const void *data) {
 int position;

 /* get hash key */
 position=tbl->h(data)%tbl->positions;
#ifdef DEBUG
printf("hash position %d\n",position);
#endif
 if (glist_sorted_insert(&(tbl->table[position]),data)) {
   tbl->size++;
   return(0); /* data inserted */
 }
 
 /* else */
 return(1); /* data not inserted: already exsists */
}


/* remove data */
/* if data is removed return 0, else return 1 */
int
htbl_remove(htbl *tbl,const void *data) {
 int position;

 /* get hash key */
 position=tbl->h(data)%tbl->positions;
#ifdef DEBUG
printf("hash position %d\n",position);
#endif

 if (glist_sorted_remove(&(tbl->table[position]),data)) {
   tbl->size--;
   return(0); /* data removed */
 }
 
 /* else */
 return(1); /* data not removed: not exsist*/
}


/* lookup data and return address*/
/* if data not found, null is returned */
void *
htbl_lookup(const htbl *tbl,const void *data) {
 int position;

 /* get hash key */
 position=tbl->h(data)%tbl->positions;
#ifdef DEBUG
printf("hash position %d\n",position);
#endif

 return(glist_sorted_lookup(&(tbl->table[position]),data));
}