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yap-6.3/packages/semweb/hash.h

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/* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: wielemak@science.uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2007, University of Amsterdam
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 library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
As a special exception, if you link this library with other files,
compiled with a Free Software compiler, to produce an executable, this
library does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
#ifndef HASH_H_INCLUDED
#define HASH_H_INCLUDED
typedef struct ptr_hash_node
{ struct ptr_hash_node *next; /* next in chain */
void *value; /* hashed value */
} ptr_hash_node;
typedef struct ptr_hash
{ int entries; /* # chains */
int shift; /* shift for pointers */
ptr_hash_node **chains; /* hash chains */
} ptr_hash;
ptr_hash *new_ptr_hash(int entries, int shift);
void destroy_ptr_hash(ptr_hash *hash);
int add_ptr_hash(ptr_hash *hash, void *value);
int for_ptr_hash(ptr_hash *hash,
int (*func)(ptr_hash_node *node, void *closure),
void *closure);
/*******************************
* ATOMS *
*******************************/
typedef ptr_hash atom_hash;
#define new_atom_hash(entries) new_ptr_hash(entries, ATOM_HASH_SHIFT)
#define destroy_atom_hash(hash) destroy_ptr_hash(hash)
#define add_atom_hash(hash, atom) add_ptr_hash(hash, (void*)(atom))
#define for_atom_hash for_ptr_hash
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SWI-Prolog note: Atoms are integers shifted by LMASK_BITS (7)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
#define POINTER_HASH_SHIFT 3
#define ATOM_HASH_SHIFT 7
#define atom_hash(a) (((unsigned long)a)>>ATOM_HASH_SHIFT)
#endif /*HASH_H_INCLUDED*/