libctf/ctf-hash.c

   1 /* Interface to hashtable implementations.
   2    Copyright (C) 2006-2023 Free Software Foundation, Inc.
   3
   4    This file is part of libctf.
   5
   6    libctf is free software; you can redistribute it and/or modify it under
   7    the terms of the GNU General Public License as published by the Free
   8    Software Foundation; either version 3, or (at your option) any later
   9    version.
  10
  11    This program is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  14    See the GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; see the file COPYING.  If not see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <ctf-impl.h>
  21 #include <string.h>
  22 #include "libiberty.h"
  23 #include "hashtab.h"
  24
  25 /* We have three hashtable implementations:
  26
  27    - ctf_hash_* is an interface to a fixed-size hash from const char * ->
  28      ctf_id_t with number of elements specified at creation time, that should
  29      support addition of items but need not support removal.
  30
  31    - ctf_dynhash_* is an interface to a dynamically-expanding hash with
  32      unknown size that should support addition of large numbers of items, and
  33      removal as well, and is used only at type-insertion time and during
  34      linking.
  35
  36    - ctf_dynset_* is an interface to a dynamically-expanding hash that contains
  37      only keys: no values.
  38
  39    These can be implemented by the same underlying hashmap if you wish.  */
  40
  41 /* The helem is used for general key/value mappings in both the ctf_hash and
  42    ctf_dynhash: the owner may not have space allocated for it, and will be
  43    garbage (not NULL!) in that case.  */
  44
  45 typedef struct ctf_helem
  46 {
  47   void *key;                     /* Either a pointer, or a coerced ctf_id_t.  */
  48   void *value;                   /* The value (possibly a coerced int).  */
  49   ctf_dynhash_t *owner;          /* The hash that owns us.  */
  50 } ctf_helem_t;
  51
  52 /* Equally, the key_free and value_free may not exist.  */
  53
  54 struct ctf_dynhash
  55 {
  56   struct htab *htab;
  57   ctf_hash_free_fun key_free;
  58   ctf_hash_free_fun value_free;
  59 };
  60
  61 /* Hash and eq functions for the dynhash and hash. */
  62
  63 unsigned int
  64 ctf_hash_integer (const void *ptr)
  65 {
  66   ctf_helem_t *hep = (ctf_helem_t *) ptr;
  67
  68   return htab_hash_pointer (hep->key);
  69 }
  70
  71 int
  72 ctf_hash_eq_integer (const void *a, const void *b)
  73 {
  74   ctf_helem_t *hep_a = (ctf_helem_t *) a;
  75   ctf_helem_t *hep_b = (ctf_helem_t *) b;
  76
  77   return htab_eq_pointer (hep_a->key, hep_b->key);
  78 }
  79
  80 unsigned int
  81 ctf_hash_string (const void *ptr)
  82 {
  83   ctf_helem_t *hep = (ctf_helem_t *) ptr;
  84
  85   return htab_hash_string (hep->key);
  86 }
  87
  88 int
  89 ctf_hash_eq_string (const void *a, const void *b)
  90 {
  91   ctf_helem_t *hep_a = (ctf_helem_t *) a;
  92   ctf_helem_t *hep_b = (ctf_helem_t *) b;
  93
  94   return !strcmp((const char *) hep_a->key, (const char *) hep_b->key);
  95 }
  96
  97 /* Hash a type_key.  */
  98 unsigned int
  99 ctf_hash_type_key (const void *ptr)
 100 {
 101   ctf_helem_t *hep = (ctf_helem_t *) ptr;
 102   ctf_link_type_key_t *k = (ctf_link_type_key_t *) hep->key;
 103
 104   return htab_hash_pointer (k->cltk_fp) + 59
 105     * htab_hash_pointer ((void *) (uintptr_t) k->cltk_idx);
 106 }
 107
 108 int
 109 ctf_hash_eq_type_key (const void *a, const void *b)
 110 {
 111   ctf_helem_t *hep_a = (ctf_helem_t *) a;
 112   ctf_helem_t *hep_b = (ctf_helem_t *) b;
 113   ctf_link_type_key_t *key_a = (ctf_link_type_key_t *) hep_a->key;
 114   ctf_link_type_key_t *key_b = (ctf_link_type_key_t *) hep_b->key;
 115
 116   return (key_a->cltk_fp == key_b->cltk_fp)
 117     && (key_a->cltk_idx == key_b->cltk_idx);
 118 }
 119
 120 /* Hash a type_id_key.  */
 121 unsigned int
 122 ctf_hash_type_id_key (const void *ptr)
 123 {
 124   ctf_helem_t *hep = (ctf_helem_t *) ptr;
 125   ctf_type_id_key_t *k = (ctf_type_id_key_t *) hep->key;
 126
 127   return htab_hash_pointer ((void *) (uintptr_t) k->ctii_input_num)
 128     + 59 * htab_hash_pointer ((void *) (uintptr_t) k->ctii_type);
 129 }
 130
 131 int
 132 ctf_hash_eq_type_id_key (const void *a, const void *b)
 133 {
 134   ctf_helem_t *hep_a = (ctf_helem_t *) a;
 135   ctf_helem_t *hep_b = (ctf_helem_t *) b;
 136   ctf_type_id_key_t *key_a = (ctf_type_id_key_t *) hep_a->key;
 137   ctf_type_id_key_t *key_b = (ctf_type_id_key_t *) hep_b->key;
 138
 139   return (key_a->ctii_input_num == key_b->ctii_input_num)
 140     && (key_a->ctii_type == key_b->ctii_type);
 141 }
 142
 143 /* The dynhash, used for hashes whose size is not known at creation time. */
 144
 145 /* Free a single ctf_helem with arbitrary key/value functions.  */
 146
 147 static void
 148 ctf_dynhash_item_free (void *item)
 149 {
 150   ctf_helem_t *helem = item;
 151
 152   if (helem->owner->key_free && helem->key)
 153     helem->owner->key_free (helem->key);
 154   if (helem->owner->value_free && helem->value)
 155     helem->owner->value_free (helem->value);
 156   free (helem);
 157 }
 158
 159 ctf_dynhash_t *
 160 ctf_dynhash_create (ctf_hash_fun hash_fun, ctf_hash_eq_fun eq_fun,
 161                     ctf_hash_free_fun key_free, ctf_hash_free_fun value_free)
 162 {
 163   ctf_dynhash_t *dynhash;
 164   htab_del del = ctf_dynhash_item_free;
 165
 166   if (key_free || value_free)
 167     dynhash = malloc (sizeof (ctf_dynhash_t));
 168   else
 169     dynhash = malloc (offsetof (ctf_dynhash_t, key_free));
 170   if (!dynhash)
 171     return NULL;
 172
 173   if (key_free == NULL && value_free == NULL)
 174     del = free;
 175
 176   /* 7 is arbitrary and untested for now.  */
 177   if ((dynhash->htab = htab_create_alloc (7, (htab_hash) hash_fun, eq_fun,
 178                                           del, xcalloc, free)) == NULL)
 179     {
 180       free (dynhash);
 181       return NULL;
 182     }
 183
 184   if (key_free || value_free)
 185     {
 186       dynhash->key_free = key_free;
 187       dynhash->value_free = value_free;
 188     }
 189
 190   return dynhash;
 191 }
 192
 193 static ctf_helem_t **
 194 ctf_hashtab_lookup (struct htab *htab, const void *key, enum insert_option insert)
 195 {
 196   ctf_helem_t tmp = { .key = (void *) key };
 197   return (ctf_helem_t **) htab_find_slot (htab, &tmp, insert);
 198 }
 199
 200 static ctf_helem_t *
 201 ctf_hashtab_insert (struct htab *htab, void *key, void *value,
 202                     ctf_hash_free_fun key_free,
 203                     ctf_hash_free_fun value_free)
 204 {
 205   ctf_helem_t **slot;
 206
 207   slot = ctf_hashtab_lookup (htab, key, INSERT);
 208
 209   if (!slot)
 210     {
 211       errno = ENOMEM;
 212       return NULL;
 213     }
 214
 215   if (!*slot)
 216     {
 217       /* Only spend space on the owner if we're going to use it: if there is a
 218          key or value freeing function.  */
 219       if (key_free || value_free)
 220         *slot = malloc (sizeof (ctf_helem_t));
 221       else
 222         *slot = malloc (offsetof (ctf_helem_t, owner));
 223       if (!*slot)
 224         return NULL;
 225       (*slot)->key = key;
 226     }
 227   else
 228     {
 229       if (key_free)
 230           key_free (key);
 231       if (value_free)
 232           value_free ((*slot)->value);
 233     }
 234   (*slot)->value = value;
 235   return *slot;
 236 }
 237
 238 int
 239 ctf_dynhash_insert (ctf_dynhash_t *hp, void *key, void *value)
 240 {
 241   ctf_helem_t *slot;
 242   ctf_hash_free_fun key_free = NULL, value_free = NULL;
 243
 244   if (hp->htab->del_f == ctf_dynhash_item_free)
 245     {
 246       key_free = hp->key_free;
 247       value_free = hp->value_free;
 248     }
 249   slot = ctf_hashtab_insert (hp->htab, key, value,
 250                              key_free, value_free);
 251
 252   if (!slot)
 253     return errno;
 254
 255   /* Keep track of the owner, so that the del function can get at the key_free
 256      and value_free functions.  Only do this if one of those functions is set:
 257      if not, the owner is not even present in the helem.  */
 258
 259   if (key_free || value_free)
 260     slot->owner = hp;
 261
 262   return 0;
 263 }
 264
 265 void
 266 ctf_dynhash_remove (ctf_dynhash_t *hp, const void *key)
 267 {
 268   ctf_helem_t hep = { (void *) key, NULL, NULL };
 269   htab_remove_elt (hp->htab, &hep);
 270 }
 271
 272 void
 273 ctf_dynhash_empty (ctf_dynhash_t *hp)
 274 {
 275   htab_empty (hp->htab);
 276 }
 277
 278 size_t
 279 ctf_dynhash_elements (ctf_dynhash_t *hp)
 280 {
 281   return htab_elements (hp->htab);
 282 }
 283
 284 void *
 285 ctf_dynhash_lookup (ctf_dynhash_t *hp, const void *key)
 286 {
 287   ctf_helem_t **slot;
 288
 289   slot = ctf_hashtab_lookup (hp->htab, key, NO_INSERT);
 290
 291   if (slot)
 292     return (*slot)->value;
 293
 294   return NULL;
 295 }
 296
 297 /* TRUE/FALSE return.  */
 298 int
 299 ctf_dynhash_lookup_kv (ctf_dynhash_t *hp, const void *key,
 300                        const void **orig_key, void **value)
 301 {
 302   ctf_helem_t **slot;
 303
 304   slot = ctf_hashtab_lookup (hp->htab, key, NO_INSERT);
 305
 306   if (slot)
 307     {
 308       if (orig_key)
 309         *orig_key = (*slot)->key;
 310       if (value)
 311         *value = (*slot)->value;
 312       return 1;
 313     }
 314   return 0;
 315 }
 316
 317 typedef struct ctf_traverse_cb_arg
 318 {
 319   ctf_hash_iter_f fun;
 320   void *arg;
 321 } ctf_traverse_cb_arg_t;
 322
 323 static int
 324 ctf_hashtab_traverse (void **slot, void *arg_)
 325 {
 326   ctf_helem_t *helem = *((ctf_helem_t **) slot);
 327   ctf_traverse_cb_arg_t *arg = (ctf_traverse_cb_arg_t *) arg_;
 328
 329   arg->fun (helem->key, helem->value, arg->arg);
 330   return 1;
 331 }
 332
 333 void
 334 ctf_dynhash_iter (ctf_dynhash_t *hp, ctf_hash_iter_f fun, void *arg_)
 335 {
 336   ctf_traverse_cb_arg_t arg = { fun, arg_ };
 337   htab_traverse (hp->htab, ctf_hashtab_traverse, &arg);
 338 }
 339
 340 typedef struct ctf_traverse_find_cb_arg
 341 {
 342   ctf_hash_iter_find_f fun;
 343   void *arg;
 344   void *found_key;
 345 } ctf_traverse_find_cb_arg_t;
 346
 347 static int
 348 ctf_hashtab_traverse_find (void **slot, void *arg_)
 349 {
 350   ctf_helem_t *helem = *((ctf_helem_t **) slot);
 351   ctf_traverse_find_cb_arg_t *arg = (ctf_traverse_find_cb_arg_t *) arg_;
 352
 353   if (arg->fun (helem->key, helem->value, arg->arg))
 354     {
 355       arg->found_key = helem->key;
 356       return 0;
 357     }
 358   return 1;
 359 }
 360
 361 void *
 362 ctf_dynhash_iter_find (ctf_dynhash_t *hp, ctf_hash_iter_find_f fun, void *arg_)
 363 {
 364   ctf_traverse_find_cb_arg_t arg = { fun, arg_, NULL };
 365   htab_traverse (hp->htab, ctf_hashtab_traverse_find, &arg);
 366   return arg.found_key;
 367 }
 368
 369 typedef struct ctf_traverse_remove_cb_arg
 370 {
 371   struct htab *htab;
 372   ctf_hash_iter_remove_f fun;
 373   void *arg;
 374 } ctf_traverse_remove_cb_arg_t;
 375
 376 static int
 377 ctf_hashtab_traverse_remove (void **slot, void *arg_)
 378 {
 379   ctf_helem_t *helem = *((ctf_helem_t **) slot);
 380   ctf_traverse_remove_cb_arg_t *arg = (ctf_traverse_remove_cb_arg_t *) arg_;
 381
 382   if (arg->fun (helem->key, helem->value, arg->arg))
 383     htab_clear_slot (arg->htab, slot);
 384   return 1;
 385 }
 386
 387 void
 388 ctf_dynhash_iter_remove (ctf_dynhash_t *hp, ctf_hash_iter_remove_f fun,
 389                          void *arg_)
 390 {
 391   ctf_traverse_remove_cb_arg_t arg = { hp->htab, fun, arg_ };
 392   htab_traverse (hp->htab, ctf_hashtab_traverse_remove, &arg);
 393 }
 394
 395 /* Traverse a dynhash in arbitrary order, in _next iterator form.
 396
 397    Mutating the dynhash while iterating is not supported (just as it isn't for
 398    htab_traverse).
 399
 400    Note: unusually, this returns zero on success and a *positive* value on
 401    error, because it does not take an fp, taking an error pointer would be
 402    incredibly clunky, and nearly all error-handling ends up stuffing the result
 403    of this into some sort of errno or ctf_errno, which is invariably
 404    positive.  So doing this simplifies essentially all callers.  */
 405 int
 406 ctf_dynhash_next (ctf_dynhash_t *h, ctf_next_t **it, void **key, void **value)
 407 {
 408   ctf_next_t *i = *it;
 409   ctf_helem_t *slot;
 410
 411   if (!i)
 412     {
 413       size_t size = htab_size (h->htab);
 414
 415       /* If the table has too many entries to fit in an ssize_t, just give up.
 416          This might be spurious, but if any type-related hashtable has ever been
 417          nearly as large as that then something very odd is going on.  */
 418       if (((ssize_t) size) < 0)
 419         return EDOM;
 420
 421       if ((i = ctf_next_create ()) == NULL)
 422         return ENOMEM;
 423
 424       i->u.ctn_hash_slot = h->htab->entries;
 425       i->cu.ctn_h = h;
 426       i->ctn_n = 0;
 427       i->ctn_size = (ssize_t) size;
 428       i->ctn_iter_fun = (void (*) (void)) ctf_dynhash_next;
 429       *it = i;
 430     }
 431
 432   if ((void (*) (void)) ctf_dynhash_next != i->ctn_iter_fun)
 433     return ECTF_NEXT_WRONGFUN;
 434
 435   if (h != i->cu.ctn_h)
 436     return ECTF_NEXT_WRONGFP;
 437
 438   if ((ssize_t) i->ctn_n == i->ctn_size)
 439     goto hash_end;
 440
 441   while ((ssize_t) i->ctn_n < i->ctn_size
 442          && (*i->u.ctn_hash_slot == HTAB_EMPTY_ENTRY
 443              || *i->u.ctn_hash_slot == HTAB_DELETED_ENTRY))
 444     {
 445       i->u.ctn_hash_slot++;
 446       i->ctn_n++;
 447     }
 448
 449   if ((ssize_t) i->ctn_n == i->ctn_size)
 450     goto hash_end;
 451
 452   slot = *i->u.ctn_hash_slot;
 453
 454   if (key)
 455     *key = slot->key;
 456   if (value)
 457     *value = slot->value;
 458
 459   i->u.ctn_hash_slot++;
 460   i->ctn_n++;
 461
 462   return 0;
 463
 464  hash_end:
 465   ctf_next_destroy (i);
 466   *it = NULL;
 467   return ECTF_NEXT_END;
 468 }
 469
 470 int
 471 ctf_dynhash_sort_by_name (const ctf_next_hkv_t *one, const ctf_next_hkv_t *two,
 472                           void *unused _libctf_unused_)
 473 {
 474   return strcmp ((char *) one->hkv_key, (char *) two->hkv_key);
 475 }
 476
 477 /* Traverse a sorted dynhash, in _next iterator form.
 478
 479    See ctf_dynhash_next for notes on error returns, etc.
 480
 481    Sort keys before iterating over them using the SORT_FUN and SORT_ARG.
 482
 483    If SORT_FUN is null, thunks to ctf_dynhash_next.  */
 484 int
 485 ctf_dynhash_next_sorted (ctf_dynhash_t *h, ctf_next_t **it, void **key,
 486                          void **value, ctf_hash_sort_f sort_fun, void *sort_arg)
 487 {
 488   ctf_next_t *i = *it;
 489
 490   if (sort_fun == NULL)
 491     return ctf_dynhash_next (h, it, key, value);
 492
 493   if (!i)
 494     {
 495       size_t els = ctf_dynhash_elements (h);
 496       ctf_next_t *accum_i = NULL;
 497       void *key, *value;
 498       int err;
 499       ctf_next_hkv_t *walk;
 500
 501       if (((ssize_t) els) < 0)
 502         return EDOM;
 503
 504       if ((i = ctf_next_create ()) == NULL)
 505         return ENOMEM;
 506
 507       if ((i->u.ctn_sorted_hkv = calloc (els, sizeof (ctf_next_hkv_t))) == NULL)
 508         {
 509           ctf_next_destroy (i);
 510           return ENOMEM;
 511         }
 512       walk = i->u.ctn_sorted_hkv;
 513
 514       i->cu.ctn_h = h;
 515
 516       while ((err = ctf_dynhash_next (h, &accum_i, &key, &value)) == 0)
 517         {
 518           walk->hkv_key = key;
 519           walk->hkv_value = value;
 520           walk++;
 521         }
 522       if (err != ECTF_NEXT_END)
 523         {
 524           ctf_next_destroy (i);
 525           return err;
 526         }
 527
 528       if (sort_fun)
 529           ctf_qsort_r (i->u.ctn_sorted_hkv, els, sizeof (ctf_next_hkv_t),
 530                        (int (*) (const void *, const void *, void *)) sort_fun,
 531                        sort_arg);
 532       i->ctn_n = 0;
 533       i->ctn_size = (ssize_t) els;
 534       i->ctn_iter_fun = (void (*) (void)) ctf_dynhash_next_sorted;
 535       *it = i;
 536     }
 537
 538   if ((void (*) (void)) ctf_dynhash_next_sorted != i->ctn_iter_fun)
 539     return ECTF_NEXT_WRONGFUN;
 540
 541   if (h != i->cu.ctn_h)
 542     return ECTF_NEXT_WRONGFP;
 543
 544   if ((ssize_t) i->ctn_n == i->ctn_size)
 545     {
 546       ctf_next_destroy (i);
 547       *it = NULL;
 548       return ECTF_NEXT_END;
 549     }
 550
 551   if (key)
 552     *key = i->u.ctn_sorted_hkv[i->ctn_n].hkv_key;
 553   if (value)
 554     *value = i->u.ctn_sorted_hkv[i->ctn_n].hkv_value;
 555   i->ctn_n++;
 556   return 0;
 557 }
 558
 559 void
 560 ctf_dynhash_destroy (ctf_dynhash_t *hp)
 561 {
 562   if (hp != NULL)
 563     htab_delete (hp->htab);
 564   free (hp);
 565 }
 566
 567 /* The dynset, used for sets of keys with no value.  The implementation of this
 568    can be much simpler, because without a value the slot can simply be the
 569    stored key, which means we don't need to store the freeing functions and the
 570    dynset itself is just a htab.  */
 571
 572 ctf_dynset_t *
 573 ctf_dynset_create (htab_hash hash_fun, htab_eq eq_fun,
 574                    ctf_hash_free_fun key_free)
 575 {
 576   /* 7 is arbitrary and untested for now.  */
 577   return (ctf_dynset_t *) htab_create_alloc (7, (htab_hash) hash_fun, eq_fun,
 578                                              key_free, xcalloc, free);
 579 }
 580
 581 /* The dynset has one complexity: the underlying implementation reserves two
 582    values for internal hash table implementation details (empty versus deleted
 583    entries).  These values are otherwise very useful for pointers cast to ints,
 584    so transform the ctf_dynset_inserted value to allow for it.  (This
 585    introduces an ambiguity in that one can no longer store these two values in
 586    the dynset, but if we pick high enough values this is very unlikely to be a
 587    problem.)
 588
 589    We leak this implementation detail to the freeing functions on the grounds
 590    that any use of these functions is overwhelmingly likely to be in sets using
 591    real pointers, which will be unaffected.  */
 592
 593 #define DYNSET_EMPTY_ENTRY_REPLACEMENT ((void *) (uintptr_t) -64)
 594 #define DYNSET_DELETED_ENTRY_REPLACEMENT ((void *) (uintptr_t) -63)
 595
 596 static void *
 597 key_to_internal (const void *key)
 598 {
 599   if (key == HTAB_EMPTY_ENTRY)
 600     return DYNSET_EMPTY_ENTRY_REPLACEMENT;
 601   else if (key == HTAB_DELETED_ENTRY)
 602     return DYNSET_DELETED_ENTRY_REPLACEMENT;
 603
 604   return (void *) key;
 605 }
 606
 607 static void *
 608 internal_to_key (const void *internal)
 609 {
 610   if (internal == DYNSET_EMPTY_ENTRY_REPLACEMENT)
 611     return HTAB_EMPTY_ENTRY;
 612   else if (internal == DYNSET_DELETED_ENTRY_REPLACEMENT)
 613     return HTAB_DELETED_ENTRY;
 614   return (void *) internal;
 615 }
 616
 617 int
 618 ctf_dynset_insert (ctf_dynset_t *hp, void *key)
 619 {
 620   struct htab *htab = (struct htab *) hp;
 621   void **slot;
 622
 623   slot = htab_find_slot (htab, key, INSERT);
 624
 625   if (!slot)
 626     {
 627       errno = ENOMEM;
 628       return -errno;
 629     }
 630
 631   if (*slot)
 632     {
 633       if (htab->del_f)
 634         (*htab->del_f) (*slot);
 635     }
 636
 637   *slot = key_to_internal (key);
 638
 639   return 0;
 640 }
 641
 642 void
 643 ctf_dynset_remove (ctf_dynset_t *hp, const void *key)
 644 {
 645   htab_remove_elt ((struct htab *) hp, key_to_internal (key));
 646 }
 647
 648 void
 649 ctf_dynset_destroy (ctf_dynset_t *hp)
 650 {
 651   if (hp != NULL)
 652     htab_delete ((struct htab *) hp);
 653 }
 654
 655 void *
 656 ctf_dynset_lookup (ctf_dynset_t *hp, const void *key)
 657 {
 658   void **slot = htab_find_slot ((struct htab *) hp,
 659                                 key_to_internal (key), NO_INSERT);
 660
 661   if (slot)
 662     return internal_to_key (*slot);
 663   return NULL;
 664 }
 665
 666 size_t
 667 ctf_dynset_elements (ctf_dynset_t *hp)
 668 {
 669   return htab_elements ((struct htab *) hp);
 670 }
 671
 672 /* TRUE/FALSE return.  */
 673 int
 674 ctf_dynset_exists (ctf_dynset_t *hp, const void *key, const void **orig_key)
 675 {
 676   void **slot = htab_find_slot ((struct htab *) hp,
 677                                 key_to_internal (key), NO_INSERT);
 678
 679   if (orig_key && slot)
 680     *orig_key = internal_to_key (*slot);
 681   return (slot != NULL);
 682 }
 683
 684 /* Look up a completely random value from the set, if any exist.
 685    Keys with value zero cannot be distinguished from a nonexistent key.  */
 686 void *
 687 ctf_dynset_lookup_any (ctf_dynset_t *hp)
 688 {
 689   struct htab *htab = (struct htab *) hp;
 690   void **slot = htab->entries;
 691   void **limit = slot + htab_size (htab);
 692
 693   while (slot < limit
 694          && (*slot == HTAB_EMPTY_ENTRY || *slot == HTAB_DELETED_ENTRY))
 695       slot++;
 696
 697   if (slot < limit)
 698     return internal_to_key (*slot);
 699   return NULL;
 700 }
 701
 702 /* Traverse a dynset in arbitrary order, in _next iterator form.
 703
 704    Otherwise, just like ctf_dynhash_next.  */
 705 int
 706 ctf_dynset_next (ctf_dynset_t *hp, ctf_next_t **it, void **key)
 707 {
 708   struct htab *htab = (struct htab *) hp;
 709   ctf_next_t *i = *it;
 710   void *slot;
 711
 712   if (!i)
 713     {
 714       size_t size = htab_size (htab);
 715
 716       /* If the table has too many entries to fit in an ssize_t, just give up.
 717          This might be spurious, but if any type-related hashtable has ever been
 718          nearly as large as that then somthing very odd is going on.  */
 719
 720       if (((ssize_t) size) < 0)
 721         return EDOM;
 722
 723       if ((i = ctf_next_create ()) == NULL)
 724         return ENOMEM;
 725
 726       i->u.ctn_hash_slot = htab->entries;
 727       i->cu.ctn_s = hp;
 728       i->ctn_n = 0;
 729       i->ctn_size = (ssize_t) size;
 730       i->ctn_iter_fun = (void (*) (void)) ctf_dynset_next;
 731       *it = i;
 732     }
 733
 734   if ((void (*) (void)) ctf_dynset_next != i->ctn_iter_fun)
 735     return ECTF_NEXT_WRONGFUN;
 736
 737   if (hp != i->cu.ctn_s)
 738     return ECTF_NEXT_WRONGFP;
 739
 740   if ((ssize_t) i->ctn_n == i->ctn_size)
 741     goto set_end;
 742
 743   while ((ssize_t) i->ctn_n < i->ctn_size
 744          && (*i->u.ctn_hash_slot == HTAB_EMPTY_ENTRY
 745              || *i->u.ctn_hash_slot == HTAB_DELETED_ENTRY))
 746     {
 747       i->u.ctn_hash_slot++;
 748       i->ctn_n++;
 749     }
 750
 751   if ((ssize_t) i->ctn_n == i->ctn_size)
 752     goto set_end;
 753
 754   slot = *i->u.ctn_hash_slot;
 755
 756   if (key)
 757     *key = internal_to_key (slot);
 758
 759   i->u.ctn_hash_slot++;
 760   i->ctn_n++;
 761
 762   return 0;
 763
 764  set_end:
 765   ctf_next_destroy (i);
 766   *it = NULL;
 767   return ECTF_NEXT_END;
 768 }
 769
 770 /* ctf_hash, used for fixed-size maps from const char * -> ctf_id_t without
 771    removal.  This is a straight cast of a hashtab.  */
 772
 773 ctf_hash_t *
 774 ctf_hash_create (unsigned long nelems, ctf_hash_fun hash_fun,
 775                  ctf_hash_eq_fun eq_fun)
 776 {
 777   return (ctf_hash_t *) htab_create_alloc (nelems, (htab_hash) hash_fun,
 778                                            eq_fun, free, xcalloc, free);
 779 }
 780
 781 uint32_t
 782 ctf_hash_size (const ctf_hash_t *hp)
 783 {
 784   return htab_elements ((struct htab *) hp);
 785 }
 786
 787 int
 788 ctf_hash_insert_type (ctf_hash_t *hp, ctf_dict_t *fp, uint32_t type,
 789                       uint32_t name)
 790 {
 791   const char *str = ctf_strraw (fp, name);
 792
 793   if (type == 0)
 794     return EINVAL;
 795
 796   if (str == NULL
 797       && CTF_NAME_STID (name) == CTF_STRTAB_1
 798       && fp->ctf_syn_ext_strtab == NULL
 799       && fp->ctf_str[CTF_NAME_STID (name)].cts_strs == NULL)
 800     return ECTF_STRTAB;
 801
 802   if (str == NULL)
 803     return ECTF_BADNAME;
 804
 805   if (str[0] == '\0')
 806     return 0;              /* Just ignore empty strings on behalf of caller.  */
 807
 808   if (ctf_hashtab_insert ((struct htab *) hp, (char *) str,
 809                           (void *) (ptrdiff_t) type, NULL, NULL) != NULL)
 810     return 0;
 811   return errno;
 812 }
 813
 814 /* if the key is already in the hash, override the previous definition with
 815    this new official definition. If the key is not present, then call
 816    ctf_hash_insert_type and hash it in.  */
 817 int
 818 ctf_hash_define_type (ctf_hash_t *hp, ctf_dict_t *fp, uint32_t type,
 819                       uint32_t name)
 820 {
 821   /* This matches the semantics of ctf_hash_insert_type in this
 822      implementation anyway.  */
 823
 824   return ctf_hash_insert_type (hp, fp, type, name);
 825 }
 826
 827 ctf_id_t
 828 ctf_hash_lookup_type (ctf_hash_t *hp, ctf_dict_t *fp __attribute__ ((__unused__)),
 829                       const char *key)
 830 {
 831   ctf_helem_t **slot;
 832
 833   slot = ctf_hashtab_lookup ((struct htab *) hp, key, NO_INSERT);
 834
 835   if (slot)
 836     return (ctf_id_t) (uintptr_t) ((*slot)->value);
 837
 838   return 0;
 839 }
 840
 841 void
 842 ctf_hash_destroy (ctf_hash_t *hp)
 843 {
 844   if (hp != NULL)
 845     htab_delete ((struct htab *) hp);
 846 }