1/*
2 * Copyright (C) 2004-2007, 2009  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1996-2001  Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* $Id: symtab.h,v 1.24.332.2 2009/01/18 23:47:41 tbox Exp $ */
19
20#ifndef ISC_SYMTAB_H
21#define ISC_SYMTAB_H 1
22
23/*****
24 ***** Module Info
25 *****/
26
27/*! \file isc/symtab.h
28 * \brief Provides a simple memory-based symbol table.
29 *
30 * Keys are C strings, and key comparisons are case-insensitive.  A type may
31 * be specified when looking up, defining, or undefining.  A type value of
32 * 0 means "match any type"; any other value will only match the given
33 * type.
34 *
35 * It's possible that a client will attempt to define a <key, type, value>
36 * tuple when a tuple with the given key and type already exists in the table.
37 * What to do in this case is specified by the client.  Possible policies are:
38 *
39 *\li	#isc_symexists_reject	Disallow the define, returning #ISC_R_EXISTS
40 *\li	#isc_symexists_replace	Replace the old value with the new.  The
41 *				undefine action (if provided) will be called
42 *				with the old <key, type, value> tuple.
43 *\li	#isc_symexists_add	Add the new tuple, leaving the old tuple in
44 *				the table.  Subsequent lookups will retrieve
45 *				the most-recently-defined tuple.
46 *
47 * A lookup of a key using type 0 will return the most-recently defined
48 * symbol with that key.  An undefine of a key using type 0 will undefine the
49 * most-recently defined symbol with that key.  Trying to define a key with
50 * type 0 is illegal.
51 *
52 * The symbol table library does not make a copy the key field, so the
53 * caller must ensure that any key it passes to isc_symtab_define() will not
54 * change until it calls isc_symtab_undefine() or isc_symtab_destroy().
55 *
56 * A user-specified action will be called (if provided) when a symbol is
57 * undefined.  It can be used to free memory associated with keys and/or
58 * values.
59 *
60 * \li MP:
61 *	The callers of this module must ensure any required synchronization.
62 *
63 * \li Reliability:
64 *	No anticipated impact.
65 *
66 * \li Resources:
67 *	TBS
68 *
69 * \li Security:
70 *	No anticipated impact.
71 *
72 * \li Standards:
73 *	None.
74 */
75
76/***
77 *** Imports.
78 ***/
79
80#include <isc/lang.h>
81#include <isc/types.h>
82
83/*
84 *** Symbol Tables.
85 ***/
86/*% Symbol table value. */
87typedef union isc_symvalue {
88	void *				as_pointer;
89	const void *			as_cpointer;
90	int				as_integer;
91	unsigned int			as_uinteger;
92} isc_symvalue_t;
93
94typedef void (*isc_symtabaction_t)(char *key, unsigned int type,
95				   isc_symvalue_t value, void *userarg);
96/*% Symbol table exists. */
97typedef enum {
98	isc_symexists_reject = 0,	/*%< Disallow the define */
99	isc_symexists_replace = 1,	/*%< Replace the old value with the new */
100	isc_symexists_add = 2		/*%< Add the new tuple */
101} isc_symexists_t;
102
103ISC_LANG_BEGINDECLS
104
105/*% Create a symbol table. */
106isc_result_t
107isc_symtab_create(isc_mem_t *mctx, unsigned int size,
108		  isc_symtabaction_t undefine_action, void *undefine_arg,
109		  isc_boolean_t case_sensitive, isc_symtab_t **symtabp);
110
111/*% Destroy a symbol table. */
112void
113isc_symtab_destroy(isc_symtab_t **symtabp);
114
115/*% Lookup a symbol table. */
116isc_result_t
117isc_symtab_lookup(isc_symtab_t *symtab, const char *key, unsigned int type,
118		  isc_symvalue_t *value);
119
120/*% Define a symbol table. */
121isc_result_t
122isc_symtab_define(isc_symtab_t *symtab, const char *key, unsigned int type,
123		  isc_symvalue_t value, isc_symexists_t exists_policy);
124
125/*% Undefine a symbol table. */
126isc_result_t
127isc_symtab_undefine(isc_symtab_t *symtab, const char *key, unsigned int type);
128
129ISC_LANG_ENDDECLS
130
131#endif /* ISC_SYMTAB_H */
132