/* hash.h -- header file for gas hash table routines
   Copyright 1987, 1992, 1993, 1995, 1999 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS 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, or (at your option)
   any later version.

   GAS 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 GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 59 Temple Place - Suite 330, Boston, MA
   02111-1307, USA.  */

#ifndef HASH_H
#define HASH_H

/* Add some declarations that, in less ancient versions of binutils,
   appear in ansidecls.h.  --mha */
#ifndef PTR
#define PTR             void *
#endif
#ifndef ATTRIBUTE_UNUSED
#define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
#endif 


struct hash_control;

/* Create a hash table.  This return a control block.  */

extern struct hash_control *hash_new (void);

/* Delete a hash table, freeing all allocated memory.  */

extern void hash_die (struct hash_control *);

/* Insert an entry into a hash table.  This returns NULL on success.
   On error, it returns a printable string indicating the error.  It
   is considered to be an error if the entry already exists in the
   hash table.  */

extern const char *hash_insert (struct hash_control *,
				const char *key, PTR value);

/* Insert or replace an entry in a hash table.  This returns NULL on
   success.  On error, it returns a printable string indicating the
   error.  If an entry already exists, its value is replaced.  */

extern const char *hash_jam (struct hash_control *,
			     const char *key, PTR value);

/* Replace an existing entry in a hash table.  This returns the old
   value stored for the entry.  If the entry is not found in the hash
   table, this does nothing and returns NULL.  */

extern PTR hash_replace (struct hash_control *, const char *key,
			 PTR value);

/* Find an entry in a hash table, returning its value.  Returns NULL
   if the entry is not found.  */

extern PTR hash_find (struct hash_control *, const char *key);

/* Delete an entry from a hash table.  This returns the value stored
   for that entry, or NULL if there is no such entry.  */

extern PTR hash_delete (struct hash_control *, const char *key);

/* Traverse a hash table.  Call the function on every entry in the
   hash table.  */

extern void hash_traverse (struct hash_control *,
			   void (*pfn) (const char *key, PTR value));

/* Print hash table statistics on the specified file.  NAME is the
   name of the hash table, used for printing a header.  */

#ifdef HASH_STATISTICS
extern void hash_print_statistics (FILE *, const char *name,
				   struct hash_control *);
#endif

#endif /* HASH_H */
