/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0 AND ISC
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

/*
 * Copyright (C) 2001 Nominum, Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC AND NOMINUM DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#pragma once

/*****
***** Module Info
*****/

/*! \file isccc/symtab.h
 * \brief
 * Provides a simple memory-based symbol table.
 *
 * Keys are C strings.  A type may be specified when looking up,
 * defining, or undefining.  A type value of 0 means "match any type";
 * any other value will only match the given type.
 *
 * It's possible that a client will attempt to define a <key, type,
 * value> tuple when a tuple with the given key and type already
 * exists in the table.  What to do in this case is specified by the
 * client.  Possible policies are:
 *
 *\li	isccc_symexists_reject	Disallow the define, returning #ISC_R_EXISTS
 *\li	isccc_symexists_replace	Replace the old value with the new.  The
 *				undefine action (if provided) will be called
 *				with the old <key, type, value> tuple.
 *\li	isccc_symexists_add	Add the new tuple, leaving the old tuple in
 *				the table.  Subsequent lookups will retrieve
 *				the most-recently-defined tuple.
 *
 * A lookup of a key using type 0 will return the most-recently
 * defined symbol with that key.  An undefine of a key using type 0
 * will undefine the most-recently defined symbol with that key.
 * Trying to define a key with type 0 is illegal.
 *
 * The symbol table library does not make a copy the key field, so the
 * caller must ensure that any key it passes to isccc_symtab_define()
 * will not change until it calls isccc_symtab_undefine() or
 * isccc_symtab_destroy().
 *
 * A user-specified action will be called (if provided) when a symbol
 * is undefined.  It can be used to free memory associated with keys
 * and/or values.
 */

/***
 *** Imports.
 ***/

#include <stdbool.h>

#include <isc/lang.h>

#include <isccc/types.h>

/***
 *** Symbol Tables.
 ***/

typedef union isccc_symvalue {
	void	    *as_pointer;
	int	     as_integer;
	unsigned int as_uinteger;
} isccc_symvalue_t;

typedef void (*isccc_symtabundefaction_t)(char *key, unsigned int type,
					  isccc_symvalue_t value,
					  void		  *userarg);

typedef bool (*isccc_symtabforeachaction_t)(char *key, unsigned int type,
					    isccc_symvalue_t value,
					    void	    *userarg);

typedef enum {
	isccc_symexists_reject = 0,
	isccc_symexists_replace = 1,
	isccc_symexists_add = 2
} isccc_symexists_t;

ISC_LANG_BEGINDECLS

isc_result_t
isccc_symtab_create(unsigned int	      size,
		    isccc_symtabundefaction_t undefine_action,
		    void *undefine_arg, bool case_sensitive,
		    isccc_symtab_t **symtabp);

void
isccc_symtab_destroy(isccc_symtab_t **symtabp);

isc_result_t
isccc_symtab_lookup(isccc_symtab_t *symtab, const char *key, unsigned int type,
		    isccc_symvalue_t *value);

isc_result_t
isccc_symtab_define(isccc_symtab_t *symtab, char *key, unsigned int type,
		    isccc_symvalue_t value, isccc_symexists_t exists_policy);

isc_result_t
isccc_symtab_undefine(isccc_symtab_t *symtab, const char *key,
		      unsigned int type);

void
isccc_symtab_foreach(isccc_symtab_t *symtab, isccc_symtabforeachaction_t action,
		     void *arg);

ISC_LANG_ENDDECLS
