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/*
* Copyright (C) 2004, 2005, 2007 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: symtab.c,v 1.30 2007/06/19 23:47:17 tbox Exp $ */
/*! \file */
#include <config.h>
#include <ctype.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/string.h>
#include <isc/symtab.h>
#include <isc/util.h>
typedef struct elt {
char * key;
unsigned int type;
isc_symvalue_t value;
LINK(struct elt) link;
} elt_t;
typedef LIST(elt_t) eltlist_t;
#define SYMTAB_MAGIC ISC_MAGIC('S', 'y', 'm', 'T')
#define VALID_SYMTAB(st) ISC_MAGIC_VALID(st, SYMTAB_MAGIC)
struct isc_symtab {
/* Unlocked. */
unsigned int magic;
isc_mem_t * mctx;
unsigned int size;
eltlist_t * table;
isc_symtabaction_t undefine_action;
void * undefine_arg;
isc_boolean_t case_sensitive;
};
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)
{
isc_symtab_t *symtab;
unsigned int i;
REQUIRE(mctx != NULL);
REQUIRE(symtabp != NULL && *symtabp == NULL);
REQUIRE(size > 0); /* Should be prime. */
symtab = (isc_symtab_t *)isc_mem_get(mctx, sizeof(*symtab));
if (symtab == NULL)
return (ISC_R_NOMEMORY);
symtab->table = (eltlist_t *)isc_mem_get(mctx,
size * sizeof(eltlist_t));
if (symtab->table == NULL) {
isc_mem_put(mctx, symtab, sizeof(*symtab));
return (ISC_R_NOMEMORY);
}
for (i = 0; i < size; i++)
INIT_LIST(symtab->table[i]);
symtab->mctx = mctx;
symtab->size = size;
symtab->undefine_action = undefine_action;
symtab->undefine_arg = undefine_arg;
symtab->case_sensitive = case_sensitive;
symtab->magic = SYMTAB_MAGIC;
*symtabp = symtab;
return (ISC_R_SUCCESS);
}
void
isc_symtab_destroy(isc_symtab_t **symtabp) {
isc_symtab_t *symtab;
unsigned int i;
elt_t *elt, *nelt;
REQUIRE(symtabp != NULL);
symtab = *symtabp;
REQUIRE(VALID_SYMTAB(symtab));
for (i = 0; i < symtab->size; i++) {
for (elt = HEAD(symtab->table[i]); elt != NULL; elt = nelt) {
nelt = NEXT(elt, link);
if (symtab->undefine_action != NULL)
(symtab->undefine_action)(elt->key,
elt->type,
elt->value,
symtab->undefine_arg);
isc_mem_put(symtab->mctx, elt, sizeof(*elt));
}
}
isc_mem_put(symtab->mctx, symtab->table,
symtab->size * sizeof(eltlist_t));
symtab->magic = 0;
isc_mem_put(symtab->mctx, symtab, sizeof(*symtab));
*symtabp = NULL;
}
static inline unsigned int
hash(const char *key, isc_boolean_t case_sensitive) {
const char *s;
unsigned int h = 0;
int c;
/*
* This hash function is similar to the one Ousterhout
* uses in Tcl.
*/
if (case_sensitive) {
for (s = key; *s != '\0'; s++) {
h += (h << 3) + *s;
}
} else {
for (s = key; *s != '\0'; s++) {
c = *s;
c = tolower((unsigned char)c);
h += (h << 3) + c;
}
}
return (h);
}
#define FIND(s, k, t, b, e) \
b = hash((k), (s)->case_sensitive) % (s)->size; \
if ((s)->case_sensitive) { \
for (e = HEAD((s)->table[b]); e != NULL; e = NEXT(e, link)) { \
if (((t) == 0 || e->type == (t)) && \
strcmp(e->key, (k)) == 0) \
break; \
} \
} else { \
for (e = HEAD((s)->table[b]); e != NULL; e = NEXT(e, link)) { \
if (((t) == 0 || e->type == (t)) && \
strcasecmp(e->key, (k)) == 0) \
break; \
} \
}
isc_result_t
isc_symtab_lookup(isc_symtab_t *symtab, const char *key, unsigned int type,
isc_symvalue_t *value)
{
unsigned int bucket;
elt_t *elt;
REQUIRE(VALID_SYMTAB(symtab));
REQUIRE(key != NULL);
FIND(symtab, key, type, bucket, elt);
if (elt == NULL)
return (ISC_R_NOTFOUND);
if (value != NULL)
*value = elt->value;
return (ISC_R_SUCCESS);
}
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)
{
unsigned int bucket;
elt_t *elt;
REQUIRE(VALID_SYMTAB(symtab));
REQUIRE(key != NULL);
REQUIRE(type != 0);
FIND(symtab, key, type, bucket, elt);
if (exists_policy != isc_symexists_add && elt != NULL) {
if (exists_policy == isc_symexists_reject)
return (ISC_R_EXISTS);
INSIST(exists_policy == isc_symexists_replace);
UNLINK(symtab->table[bucket], elt, link);
if (symtab->undefine_action != NULL)
(symtab->undefine_action)(elt->key, elt->type,
elt->value,
symtab->undefine_arg);
} else {
elt = (elt_t *)isc_mem_get(symtab->mctx, sizeof(*elt));
if (elt == NULL)
return (ISC_R_NOMEMORY);
ISC_LINK_INIT(elt, link);
}
/*
* Though the "key" can be const coming in, it is not stored as const
* so that the calling program can easily have writable access to
* it in its undefine_action function. In the event that it *was*
* truly const coming in and then the caller modified it anyway ...
* well, don't do that!
*/
DE_CONST(key, elt->key);
elt->type = type;
elt->value = value;
/*
* We prepend so that the most recent definition will be found.
*/
PREPEND(symtab->table[bucket], elt, link);
return (ISC_R_SUCCESS);
}
isc_result_t
isc_symtab_undefine(isc_symtab_t *symtab, const char *key, unsigned int type) {
unsigned int bucket;
elt_t *elt;
REQUIRE(VALID_SYMTAB(symtab));
REQUIRE(key != NULL);
FIND(symtab, key, type, bucket, elt);
if (elt == NULL)
return (ISC_R_NOTFOUND);
if (symtab->undefine_action != NULL)
(symtab->undefine_action)(elt->key, elt->type,
elt->value, symtab->undefine_arg);
UNLINK(symtab->table[bucket], elt, link);
isc_mem_put(symtab->mctx, elt, sizeof(*elt));
return (ISC_R_SUCCESS);
}
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