2 * Copyright (C) 2004 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1996-2001 Internet Software Consortium.
5 * Permission to use, copy, modify, and 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.
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.
18 /* $Id: symtab.h,v 1.16.206.1 2004/03/06 08:14:49 marka Exp $ */
21 #define ISC_SYMTAB_H 1
30 * Provides a simple memory-based symbol table.
32 * Keys are C strings, and key comparisons are case-insenstive. A type may
33 * be specified when looking up, defining, or undefining. A type value of
34 * 0 means "match any type"; any other value will only match the given
37 * It's possible that a client will attempt to define a <key, type, value>
38 * tuple when a tuple with the given key and type already exists in the table.
39 * What to do in this case is specified by the client. Possible policies are:
41 * isc_symexists_reject Disallow the define, returning ISC_R_EXISTS
42 * isc_symexists_replace Replace the old value with the new. The
43 * undefine action (if provided) will be called
44 * with the old <key, type, value> tuple.
45 * isc_symexists_add Add the new tuple, leaving the old tuple in
46 * the table. Subsequent lookups will retrieve
47 * the most-recently-defined tuple.
49 * A lookup of a key using type 0 will return the most-recently defined
50 * symbol with that key. An undefine of a key using type 0 will undefine the
51 * most-recently defined symbol with that key. Trying to define a key with
54 * The symbol table library does not make a copy the key field, so the
55 * caller must ensure that any key it passes to isc_symtab_define() will not
56 * change until it calls isc_symtab_undefine() or isc_symtab_destroy().
58 * A user-specified action will be called (if provided) when a symbol is
59 * undefined. It can be used to free memory associated with keys and/or
63 * The callers of this module must ensure any required synchronization.
66 * No anticipated impact.
72 * No anticipated impact.
83 #include <isc/types.h>
89 typedef union isc_symvalue {
92 unsigned int as_uinteger;
95 typedef void (*isc_symtabaction_t)(char *key, unsigned int type,
96 isc_symvalue_t value, void *userarg);
99 isc_symexists_reject = 0,
100 isc_symexists_replace = 1,
101 isc_symexists_add = 2
107 isc_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);
112 isc_symtab_destroy(isc_symtab_t **symtabp);
115 isc_symtab_lookup(isc_symtab_t *symtab, const char *key, unsigned int type,
116 isc_symvalue_t *value);
119 isc_symtab_define(isc_symtab_t *symtab, const char *key, unsigned int type,
120 isc_symvalue_t value, isc_symexists_t exists_policy);
123 isc_symtab_undefine(isc_symtab_t *symtab, const char *key, unsigned int type);
127 #endif /* ISC_SYMTAB_H */