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Diffstat (limited to 'bsd/freebsd/contrib/ntp/lib/isc/include/isc/symtab.h')
| -rw-r--r-- | bsd/freebsd/contrib/ntp/lib/isc/include/isc/symtab.h | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/bsd/freebsd/contrib/ntp/lib/isc/include/isc/symtab.h b/bsd/freebsd/contrib/ntp/lib/isc/include/isc/symtab.h new file mode 100644 index 0000000..9d0e5e2 --- /dev/null +++ b/bsd/freebsd/contrib/ntp/lib/isc/include/isc/symtab.h @@ -0,0 +1,139 @@ +/* + * Copyright (C) 2004-2007, 2009, 2011, 2012 Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 1996-2001 Internet Software Consortium. + * + * 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 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. + */ + +/* $Id$ */ + +#ifndef ISC_SYMTAB_H +#define ISC_SYMTAB_H 1 + +/***** + ***** Module Info + *****/ + +/*! \file isc/symtab.h + * \brief Provides a simple memory-based symbol table. + * + * Keys are C strings, and key comparisons are case-insensitive. 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 #isc_symexists_reject Disallow the define, returning #ISC_R_EXISTS + *\li #isc_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 #isc_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 isc_symtab_define() will not + * change until it calls isc_symtab_undefine() or isc_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. + * + * A symbol table is implemented as a hash table of lists; the size of the + * hash table is set by the 'size' parameter to isc_symtbl_create(). When + * the number of entries in the symbol table reaches three quarters of this + * value, the hash table is reallocated with size doubled, in order to + * optimize lookup performance. This has a negative effect on insertion + * performance, which can be mitigated by sizing the table appropriately + * when creating it. + * + * \li MP: + * The callers of this module must ensure any required synchronization. + * + * \li Reliability: + * No anticipated impact. + * + * \li Resources: + * TBS + * + * \li Security: + * No anticipated impact. + * + * \li Standards: + * None. + */ + +/*** + *** Imports. + ***/ + +#include <isc/lang.h> +#include <isc/types.h> + +/* + *** Symbol Tables. + ***/ +/*% Symbol table value. */ +typedef union isc_symvalue { + void * as_pointer; + const void * as_cpointer; + int as_integer; + unsigned int as_uinteger; +} isc_symvalue_t; + +typedef void (*isc_symtabaction_t)(char *key, unsigned int type, + isc_symvalue_t value, void *userarg); +/*% Symbol table exists. */ +typedef enum { + isc_symexists_reject = 0, /*%< Disallow the define */ + isc_symexists_replace = 1, /*%< Replace the old value with the new */ + isc_symexists_add = 2 /*%< Add the new tuple */ +} isc_symexists_t; + +ISC_LANG_BEGINDECLS + +/*% Create a symbol table. */ +isc_result_t +isc_symtab_create(isc_mem_t *mctx, unsigned int size, + isc_symtabaction_t undefine_action, void *undefine_arg, + isc_boolean_t case_sensitive, isc_symtab_t **symtabp); + +/*% Destroy a symbol table. */ +void +isc_symtab_destroy(isc_symtab_t **symtabp); + +/*% Lookup a symbol table. */ +isc_result_t +isc_symtab_lookup(isc_symtab_t *symtab, const char *key, unsigned int type, + isc_symvalue_t *value); + +/*% Define a symbol table. */ +isc_result_t +isc_symtab_define(isc_symtab_t *symtab, const char *key, unsigned int type, + isc_symvalue_t value, isc_symexists_t exists_policy); + +/*% Undefine a symbol table. */ +isc_result_t +isc_symtab_undefine(isc_symtab_t *symtab, const char *key, unsigned int type); + +ISC_LANG_ENDDECLS + +#endif /* ISC_SYMTAB_H */ |