/* hash.h: declarations for a hash table.

   Copyright 1994, 1995, 2008, 2010-2012 Karl Berry.
   Copyright 1999, 2005 Olaf Weber.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   This library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this library; if not, see <http://www.gnu.org/licenses/>.  */

#ifndef HASH_H
#define HASH_H

#include <kpathsea/c-proto.h>
#include <kpathsea/types.h>

/*
 * The code freeing strings and hash tables is enabled/disabled
 * by KPATHSEA_CAN_FREE.
 */
/* At the moment can not free */
#define KPATHSEA_CAN_FREE 0

/* A single (key,value) pair.  */
typedef struct hash_element_struct
{
  const_string key;
  const_string value;
  struct hash_element_struct *next;
} hash_element_type;

/* The usual arrangement of buckets initialized to null.  */
typedef struct
{
  hash_element_type **buckets;
  unsigned size;
} hash_table_type;


/* Create a hash table of size SIZE.  */
extern KPSEDLL hash_table_type hash_create (unsigned size);

/* Insert the (KEY,VALUE) association into TABLE.  KEY may have more
   than one VALUE.  Neither KEY nor VALUE is copied.  */
extern KPSEDLL void hash_insert (hash_table_type *table,
                                    const_string key,
                                    const_string value);

#ifdef MAKE_KPSE_DLL /* libkpathsea internal only */

/* Insert the (KEY, VALUE) association into TABLE.  KEY may have more
   than one VALUE.  Neither KEY nor VALUE is copied.  Assume that KEY
   is already normalized (all lowercase) on platforms where this matters. */
extern void hash_insert_normalized (hash_table_type *table,
                                               const_string key,
                                               const_string value);

#endif /* MAKE_KPSE_DLL */

/* Remove the (KEY,VALUE) association from TABLE.  */
extern KPSEDLL void hash_remove (hash_table_type *table,  const_string key,
                                    const_string value);

/* Look up KEY in TABLE, and return NULL-terminated list of all matching
   values (not copies), in insertion order.  If none, return NULL.  */
extern KPSEDLL const_string *hash_lookup (hash_table_type table, const_string key);

#ifdef MAKE_KPSE_DLL /* libkpathsea internal only */

/* Print TABLE to stderr.  */
extern void hash_print (hash_table_type table, boolean summary_only);

#if KPATHSEA_CAN_FREE
/* Drop the TABLE */
extern void hash_free (hash_table_type table);
#endif

#endif /* MAKE_KPSE_DLL */

#endif /* not HASH_H */