external/bsd/bind/dist/lib/isc/symtab.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (C) 1996-2001  Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  12  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  13  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  14  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  15  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  16  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  17  * PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 /* Id: symtab.c,v 1.30 2007/06/19 23:47:17 tbox Exp */
  21
  22 /*! \file */
  23
  24 #include <config.h>
  25
  26 #include <ctype.h>
  27
  28 #include <isc/magic.h>
  29 #include <isc/mem.h>
  30 #include <isc/string.h>
  31 #include <isc/symtab.h>
  32 #include <isc/util.h>
  33
  34 typedef struct elt {
  35         char *                          key;
  36         unsigned int                    type;
  37         isc_symvalue_t                  value;
  38         LINK(struct elt)                link;
  39 } elt_t;
  40
  41 typedef LIST(elt_t)                     eltlist_t;
  42
  43 #define SYMTAB_MAGIC                    ISC_MAGIC('S', 'y', 'm', 'T')
  44 #define VALID_SYMTAB(st)                ISC_MAGIC_VALID(st, SYMTAB_MAGIC)
  45
  46 struct isc_symtab {
  47         /* Unlocked. */
  48         unsigned int                    magic;
  49         isc_mem_t *                     mctx;
  50         unsigned int                    size;
  51         eltlist_t *                     table;
  52         isc_symtabaction_t              undefine_action;
  53         void *                          undefine_arg;
  54         isc_boolean_t                   case_sensitive;
  55 };
  56
  57 isc_result_t
  58 isc_symtab_create(isc_mem_t *mctx, unsigned int size,
  59                   isc_symtabaction_t undefine_action,
  60                   void *undefine_arg,
  61                   isc_boolean_t case_sensitive,
  62                   isc_symtab_t **symtabp)
  63 {
  64         isc_symtab_t *symtab;
  65         unsigned int i;
  66
  67         REQUIRE(mctx != NULL);
  68         REQUIRE(symtabp != NULL && *symtabp == NULL);
  69         REQUIRE(size > 0);      /* Should be prime. */
  70
  71         symtab = (isc_symtab_t *)isc_mem_get(mctx, sizeof(*symtab));
  72         if (symtab == NULL)
  73                 return (ISC_R_NOMEMORY);
  74         symtab->table = (eltlist_t *)isc_mem_get(mctx,
  75                                                  size * sizeof(eltlist_t));
  76         if (symtab->table == NULL) {
  77                 isc_mem_put(mctx, symtab, sizeof(*symtab));
  78                 return (ISC_R_NOMEMORY);
  79         }
  80         for (i = 0; i < size; i++)
  81                 INIT_LIST(symtab->table[i]);
  82         symtab->mctx = mctx;
  83         symtab->size = size;
  84         symtab->undefine_action = undefine_action;
  85         symtab->undefine_arg = undefine_arg;
  86         symtab->case_sensitive = case_sensitive;
  87         symtab->magic = SYMTAB_MAGIC;
  88
  89         *symtabp = symtab;
  90
  91         return (ISC_R_SUCCESS);
  92 }
  93
  94 void
  95 isc_symtab_destroy(isc_symtab_t **symtabp) {
  96         isc_symtab_t *symtab;
  97         unsigned int i;
  98         elt_t *elt, *nelt;
  99
 100         REQUIRE(symtabp != NULL);
 101         symtab = *symtabp;
 102         REQUIRE(VALID_SYMTAB(symtab));
 103
 104         for (i = 0; i < symtab->size; i++) {
 105                 for (elt = HEAD(symtab->table[i]); elt != NULL; elt = nelt) {
 106                         nelt = NEXT(elt, link);
 107                         if (symtab->undefine_action != NULL)
 108                                (symtab->undefine_action)(elt->key,
 109                                                          elt->type,
 110                                                          elt->value,
 111                                                          symtab->undefine_arg);
 112                         isc_mem_put(symtab->mctx, elt, sizeof(*elt));
 113                 }
 114         }
 115         isc_mem_put(symtab->mctx, symtab->table,
 116                     symtab->size * sizeof(eltlist_t));
 117         symtab->magic = 0;
 118         isc_mem_put(symtab->mctx, symtab, sizeof(*symtab));
 119
 120         *symtabp = NULL;
 121 }
 122
 123 static inline unsigned int
 124 hash(const char *key, isc_boolean_t case_sensitive) {
 125         const char *s;
 126         unsigned int h = 0;
 127         int c;
 128
 129         /*
 130          * This hash function is similar to the one Ousterhout
 131          * uses in Tcl.
 132          */
 133
 134         if (case_sensitive) {
 135                 for (s = key; *s != '\0'; s++) {
 136                         h += (h << 3) + *s;
 137                 }
 138         } else {
 139                 for (s = key; *s != '\0'; s++) {
 140                         c = *s;
 141                         c = tolower((unsigned char)c);
 142                         h += (h << 3) + c;
 143                 }
 144         }
 145
 146         return (h);
 147 }
 148
 149 #define FIND(s, k, t, b, e) \
 150         b = hash((k), (s)->case_sensitive) % (s)->size; \
 151         if ((s)->case_sensitive) { \
 152                 for (e = HEAD((s)->table[b]); e != NULL; e = NEXT(e, link)) { \
 153                         if (((t) == 0 || e->type == (t)) && \
 154                             strcmp(e->key, (k)) == 0) \
 155                                 break; \
 156                 } \
 157         } else { \
 158                 for (e = HEAD((s)->table[b]); e != NULL; e = NEXT(e, link)) { \
 159                         if (((t) == 0 || e->type == (t)) && \
 160                             strcasecmp(e->key, (k)) == 0) \
 161                                 break; \
 162                 } \
 163         }
 164
 165 isc_result_t
 166 isc_symtab_lookup(isc_symtab_t *symtab, const char *key, unsigned int type,
 167                   isc_symvalue_t *value)
 168 {
 169         unsigned int bucket;
 170         elt_t *elt;
 171
 172         REQUIRE(VALID_SYMTAB(symtab));
 173         REQUIRE(key != NULL);
 174
 175         FIND(symtab, key, type, bucket, elt);
 176
 177         if (elt == NULL)
 178                 return (ISC_R_NOTFOUND);
 179
 180         if (value != NULL)
 181                 *value = elt->value;
 182
 183         return (ISC_R_SUCCESS);
 184 }
 185
 186 isc_result_t
 187 isc_symtab_define(isc_symtab_t *symtab, const char *key, unsigned int type,
 188                   isc_symvalue_t value, isc_symexists_t exists_policy)
 189 {
 190         unsigned int bucket;
 191         elt_t *elt;
 192
 193         REQUIRE(VALID_SYMTAB(symtab));
 194         REQUIRE(key != NULL);
 195         REQUIRE(type != 0);
 196
 197         FIND(symtab, key, type, bucket, elt);
 198
 199         if (exists_policy != isc_symexists_add && elt != NULL) {
 200                 if (exists_policy == isc_symexists_reject)
 201                         return (ISC_R_EXISTS);
 202                 INSIST(exists_policy == isc_symexists_replace);
 203                 UNLINK(symtab->table[bucket], elt, link);
 204                 if (symtab->undefine_action != NULL)
 205                         (symtab->undefine_action)(elt->key, elt->type,
 206                                                   elt->value,
 207                                                   symtab->undefine_arg);
 208         } else {
 209                 elt = (elt_t *)isc_mem_get(symtab->mctx, sizeof(*elt));
 210                 if (elt == NULL)
 211                         return (ISC_R_NOMEMORY);
 212                 ISC_LINK_INIT(elt, link);
 213         }
 214
 215         /*
 216          * Though the "key" can be const coming in, it is not stored as const
 217          * so that the calling program can easily have writable access to
 218          * it in its undefine_action function.  In the event that it *was*
 219          * truly const coming in and then the caller modified it anyway ...
 220          * well, don't do that!
 221          */
 222         DE_CONST(key, elt->key);
 223         elt->type = type;
 224         elt->value = value;
 225
 226         /*
 227          * We prepend so that the most recent definition will be found.
 228          */
 229         PREPEND(symtab->table[bucket], elt, link);
 230
 231         return (ISC_R_SUCCESS);
 232 }
 233
 234 isc_result_t
 235 isc_symtab_undefine(isc_symtab_t *symtab, const char *key, unsigned int type) {
 236         unsigned int bucket;
 237         elt_t *elt;
 238
 239         REQUIRE(VALID_SYMTAB(symtab));
 240         REQUIRE(key != NULL);
 241
 242         FIND(symtab, key, type, bucket, elt);
 243
 244         if (elt == NULL)
 245                 return (ISC_R_NOTFOUND);
 246
 247         if (symtab->undefine_action != NULL)
 248                 (symtab->undefine_action)(elt->key, elt->type,
 249                                           elt->value, symtab->undefine_arg);
 250         UNLINK(symtab->table[bucket], elt, link);
 251         isc_mem_put(symtab->mctx, elt, sizeof(*elt));
 252
 253         return (ISC_R_SUCCESS);
 254 }