summaryrefslogtreecommitdiff
path: root/gdb/dictionary.c
blob: bae1c0183e953907a9e5dd73d35d4323088e0c66 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
/* Routines for name->symbol lookups in GDB.
   
   Copyright (C) 2003, 2007 Free Software Foundation, Inc.

   Contributed by David Carlton <carlton@bactrian.org> and by Kealia,
   Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.  */

#include "defs.h"
#include "gdb_obstack.h"
#include "symtab.h"
#include "buildsym.h"
#include "gdb_assert.h"
#include "dictionary.h"

/* This file implements dictionaries, which are tables that associate
   symbols to names.  They are represented by an opaque type 'struct
   dictionary'.  That type has various internal implementations, which
   you can choose between depending on what properties you need
   (e.g. fast lookup, order-preserving, expandable).

   Each dictionary starts with a 'virtual function table' that
   contains the functions that actually implement the various
   operations that dictionaries provide.  (Note, however, that, for
   the sake of client code, we also provide some functions that can be
   implemented generically in terms of the functions in the vtable.)

   To add a new dictionary implementation <impl>, what you should do
   is:

   * Add a new element DICT_<IMPL> to dict_type.
   
   * Create a new structure dictionary_<impl>.  If your new
   implementation is a variant of an existing one, make sure that
   their structs have the same initial data members.  Define accessor
   macros for your new data members.

   * Implement all the functions in dict_vector as static functions,
   whose name is the same as the corresponding member of dict_vector
   plus _<impl>.  You don't have to do this for those members where
   you can reuse existing generic functions
   (e.g. add_symbol_nonexpandable, free_obstack) or in the case where
   your new implementation is a variant of an existing implementation
   and where the variant doesn't affect the member function in
   question.

   * Define a static const struct dict_vector dict_<impl>_vector.

   * Define a function dict_create_<impl> to create these
   gizmos.  Add its declaration to dictionary.h.

   To add a new operation <op> on all existing implementations, what
   you should do is:

   * Add a new member <op> to struct dict_vector.

   * If there is useful generic behavior <op>, define a static
   function <op>_something_informative that implements that behavior.
   (E.g. add_symbol_nonexpandable, free_obstack.)

   * For every implementation <impl> that should have its own specific
   behavior for <op>, define a static function <op>_<impl>
   implementing it.

   * Modify all existing dict_vector_<impl>'s to include the appropriate
   member.

   * Define a function dict_<op> that looks up <op> in the dict_vector
   and calls the appropriate function.  Add a declaration for
   dict_<op> to dictionary.h.
   
*/

/* An enum representing the various implementations of dictionaries.
   Used only for debugging.  */

enum dict_type
  {
    /* Symbols are stored in a fixed-size hash table.  */
    DICT_HASHED,
    /* Symbols are stored in an expandable hash table.  */
    DICT_HASHED_EXPANDABLE,
    /* Symbols are stored in a fixed-size array.  */
    DICT_LINEAR,
    /* Symbols are stored in an expandable array.  */
    DICT_LINEAR_EXPANDABLE
  };

/* The virtual function table.  */

struct dict_vector
{
  /* The type of the dictionary.  This is only here to make debugging
     a bit easier; it's not actually used.  */
  enum dict_type type;
  /* The function to free a dictionary.  */
  void (*free) (struct dictionary *dict);
  /* Add a symbol to a dictionary, if possible.  */
  void (*add_symbol) (struct dictionary *dict, struct symbol *sym);
  /* Iterator functions.  */
  struct symbol *(*iterator_first) (const struct dictionary *dict,
				    struct dict_iterator *iterator);
  struct symbol *(*iterator_next) (struct dict_iterator *iterator);
  /* Functions to iterate over symbols with a given name.  */
  struct symbol *(*iter_name_first) (const struct dictionary *dict,
				     const char *name,
				     struct dict_iterator *iterator);
  struct symbol *(*iter_name_next) (const char *name,
				    struct dict_iterator *iterator);
  /* A size function, for maint print symtabs.  */
  int (*size) (const struct dictionary *dict);
};

/* Now comes the structs used to store the data for different
   implementations.  If two implementations have data in common, put
   the common data at the top of their structs, ordered in the same
   way.  */

struct dictionary_hashed
{
  int nbuckets;
  struct symbol **buckets;
};

struct dictionary_hashed_expandable
{
  /* How many buckets we currently have.  */
  int nbuckets;
  struct symbol **buckets;
  /* How many syms we currently have; we need this so we will know
     when to add more buckets.  */
  int nsyms;
};

struct dictionary_linear
{
  int nsyms;
  struct symbol **syms;
};

struct dictionary_linear_expandable
{
  /* How many symbols we currently have.  */
  int nsyms;
  struct symbol **syms;
  /* How many symbols we can store before needing to reallocate.  */
  int capacity;
};

/* And now, the star of our show.  */

struct dictionary
{
  const struct dict_vector *vector;
  union
  {
    struct dictionary_hashed hashed;
    struct dictionary_hashed_expandable hashed_expandable;
    struct dictionary_linear linear;
    struct dictionary_linear_expandable linear_expandable;
  }
  data;
};

/* Accessor macros.  */

#define DICT_VECTOR(d)			(d)->vector

/* These can be used for DICT_HASHED_EXPANDABLE, too.  */

#define DICT_HASHED_NBUCKETS(d)		(d)->data.hashed.nbuckets
#define DICT_HASHED_BUCKETS(d)		(d)->data.hashed.buckets
#define DICT_HASHED_BUCKET(d,i)		DICT_HASHED_BUCKETS (d) [i]

#define DICT_HASHED_EXPANDABLE_NSYMS(d)	(d)->data.hashed_expandable.nsyms

/* These can be used for DICT_LINEAR_EXPANDABLEs, too.  */

#define DICT_LINEAR_NSYMS(d)		(d)->data.linear.nsyms
#define DICT_LINEAR_SYMS(d)		(d)->data.linear.syms
#define DICT_LINEAR_SYM(d,i)		DICT_LINEAR_SYMS (d) [i]

#define DICT_LINEAR_EXPANDABLE_CAPACITY(d) \
		(d)->data.linear_expandable.capacity

/* The initial size of a DICT_*_EXPANDABLE dictionary.  */

#define DICT_EXPANDABLE_INITIAL_CAPACITY 10

/* This calculates the number of buckets we'll use in a hashtable,
   given the number of symbols that it will contain.  */

#define DICT_HASHTABLE_SIZE(n)	((n)/5 + 1)

/* Accessor macros for dict_iterators; they're here rather than
   dictionary.h because code elsewhere should treat dict_iterators as
   opaque.  */

/* The dictionary that the iterator is associated to.  */
#define DICT_ITERATOR_DICT(iter)		(iter)->dict
/* For linear dictionaries, the index of the last symbol returned; for
   hashed dictionaries, the bucket of the last symbol returned.  */
#define DICT_ITERATOR_INDEX(iter)		(iter)->index
/* For hashed dictionaries, this points to the last symbol returned;
   otherwise, this is unused.  */
#define DICT_ITERATOR_CURRENT(iter)		(iter)->current

/* Declarations of functions for vectors.  */

/* Functions that might work across a range of dictionary types.  */

static void add_symbol_nonexpandable (struct dictionary *dict,
				      struct symbol *sym);

static void free_obstack (struct dictionary *dict);

/* Functions for DICT_HASHED and DICT_HASHED_EXPANDABLE
   dictionaries.  */

static struct symbol *iterator_first_hashed (const struct dictionary *dict,
					     struct dict_iterator *iterator);

static struct symbol *iterator_next_hashed (struct dict_iterator *iterator);

static struct symbol *iter_name_first_hashed (const struct dictionary *dict,
					      const char *name,
					      struct dict_iterator *iterator);

static struct symbol *iter_name_next_hashed (const char *name,
					     struct dict_iterator *iterator);

/* Functions only for DICT_HASHED.  */

static int size_hashed (const struct dictionary *dict);

/* Functions only for DICT_HASHED_EXPANDABLE.  */

static void free_hashed_expandable (struct dictionary *dict);

static void add_symbol_hashed_expandable (struct dictionary *dict,
					  struct symbol *sym);

static int size_hashed_expandable (const struct dictionary *dict);

/* Functions for DICT_LINEAR and DICT_LINEAR_EXPANDABLE
   dictionaries.  */

static struct symbol *iterator_first_linear (const struct dictionary *dict,
					     struct dict_iterator *iterator);

static struct symbol *iterator_next_linear (struct dict_iterator *iterator);

static struct symbol *iter_name_first_linear (const struct dictionary *dict,
					      const char *name,
					      struct dict_iterator *iterator);

static struct symbol *iter_name_next_linear (const char *name,
					     struct dict_iterator *iterator);

static int size_linear (const struct dictionary *dict);

/* Functions only for DICT_LINEAR_EXPANDABLE.  */

static void free_linear_expandable (struct dictionary *dict);

static void add_symbol_linear_expandable (struct dictionary *dict,
					  struct symbol *sym);

/* Various vectors that we'll actually use.  */

static const struct dict_vector dict_hashed_vector =
  {
    DICT_HASHED,			/* type */
    free_obstack,			/* free */
    add_symbol_nonexpandable,		/* add_symbol */
    iterator_first_hashed,		/* iteractor_first */
    iterator_next_hashed,		/* iterator_next */
    iter_name_first_hashed,		/* iter_name_first */
    iter_name_next_hashed,		/* iter_name_next */
    size_hashed,			/* size */
  };

static const struct dict_vector dict_hashed_expandable_vector =
  {
    DICT_HASHED_EXPANDABLE,		/* type */
    free_hashed_expandable,		/* free */
    add_symbol_hashed_expandable,	/* add_symbol */
    iterator_first_hashed,		/* iteractor_first */
    iterator_next_hashed,		/* iterator_next */
    iter_name_first_hashed,		/* iter_name_first */
    iter_name_next_hashed,		/* iter_name_next */
    size_hashed_expandable,		/* size */
  };

static const struct dict_vector dict_linear_vector =
  {
    DICT_LINEAR,			/* type */
    free_obstack,			/* free */
    add_symbol_nonexpandable,		/* add_symbol */
    iterator_first_linear,		/* iteractor_first */
    iterator_next_linear,		/* iterator_next */
    iter_name_first_linear,		/* iter_name_first */
    iter_name_next_linear,		/* iter_name_next */
    size_linear,			/* size */
  };

static const struct dict_vector dict_linear_expandable_vector =
  {
    DICT_LINEAR_EXPANDABLE,		/* type */
    free_linear_expandable,		/* free */
    add_symbol_linear_expandable,	/* add_symbol */
    iterator_first_linear,		/* iteractor_first */
    iterator_next_linear,		/* iterator_next */
    iter_name_first_linear,		/* iter_name_first */
    iter_name_next_linear,		/* iter_name_next */
    size_linear,			/* size */
  };

/* Declarations of helper functions (i.e. ones that don't go into
   vectors).  */

static struct symbol *iterator_hashed_advance (struct dict_iterator *iter);

static void insert_symbol_hashed (struct dictionary *dict,
				  struct symbol *sym);

static void expand_hashtable (struct dictionary *dict);

/* The creation functions.  */

/* Create a dictionary implemented via a fixed-size hashtable.  All
   memory it uses is allocated on OBSTACK; the environment is
   initialized from SYMBOL_LIST.  */

struct dictionary *
dict_create_hashed (struct obstack *obstack,
		    const struct pending *symbol_list)
{
  struct dictionary *retval;
  int nsyms = 0, nbuckets, i;
  struct symbol **buckets;
  const struct pending *list_counter;

  retval = obstack_alloc (obstack, sizeof (struct dictionary));
  DICT_VECTOR (retval) = &dict_hashed_vector;

  /* Calculate the number of symbols, and allocate space for them.  */
  for (list_counter = symbol_list;
       list_counter != NULL;
       list_counter = list_counter->next)
    {
      nsyms += list_counter->nsyms;
    }
  nbuckets = DICT_HASHTABLE_SIZE (nsyms);
  DICT_HASHED_NBUCKETS (retval) = nbuckets;
  buckets = obstack_alloc (obstack, nbuckets * sizeof (struct symbol *));
  memset (buckets, 0, nbuckets * sizeof (struct symbol *));
  DICT_HASHED_BUCKETS (retval) = buckets;

  /* Now fill the buckets.  */
  for (list_counter = symbol_list;
       list_counter != NULL;
       list_counter = list_counter->next)
    {
      for (i = list_counter->nsyms - 1; i >= 0; --i)
	{
	  insert_symbol_hashed (retval, list_counter->symbol[i]);
	}
    }

  return retval;
}

/* Create a dictionary implemented via a hashtable that grows as
   necessary.  The dictionary is initially empty; to add symbols to
   it, call dict_add_symbol().  Call dict_free() when you're done with
   it.  */

extern struct dictionary *
dict_create_hashed_expandable (void)
{
  struct dictionary *retval;

  retval = xmalloc (sizeof (struct dictionary));
  DICT_VECTOR (retval) = &dict_hashed_expandable_vector;
  DICT_HASHED_NBUCKETS (retval) = DICT_EXPANDABLE_INITIAL_CAPACITY;
  DICT_HASHED_BUCKETS (retval) = xcalloc (DICT_EXPANDABLE_INITIAL_CAPACITY,
					  sizeof (struct symbol *));
  DICT_HASHED_EXPANDABLE_NSYMS (retval) = 0;

  return retval;
}

/* Create a dictionary implemented via a fixed-size array.  All memory
   it uses is allocated on OBSTACK; the environment is initialized
   from the SYMBOL_LIST.  The symbols are ordered in the same order
   that they're found in SYMBOL_LIST.  */

struct dictionary *
dict_create_linear (struct obstack *obstack,
		    const struct pending *symbol_list)
{
  struct dictionary *retval;
  int nsyms = 0, i, j;
  struct symbol **syms;
  const struct pending *list_counter;

  retval = obstack_alloc (obstack, sizeof (struct dictionary));
  DICT_VECTOR (retval) = &dict_linear_vector;

  /* Calculate the number of symbols, and allocate space for them.  */
  for (list_counter = symbol_list;
       list_counter != NULL;
       list_counter = list_counter->next)
    {
      nsyms += list_counter->nsyms;
    }
  DICT_LINEAR_NSYMS (retval) = nsyms;
  syms = obstack_alloc (obstack, nsyms * sizeof (struct symbol *));
  DICT_LINEAR_SYMS (retval) = syms;

  /* Now fill in the symbols.  Start filling in from the back, so as
     to preserve the original order of the symbols.  */
  for (list_counter = symbol_list, j = nsyms - 1;
       list_counter != NULL;
       list_counter = list_counter->next)
    {
      for (i = list_counter->nsyms - 1;
	   i >= 0;
	   --i, --j)
	{
	  syms[j] = list_counter->symbol[i];
	}
    }

  return retval;
}

/* Create a dictionary implemented via an array that grows as
   necessary.  The dictionary is initially empty; to add symbols to
   it, call dict_add_symbol().  Call dict_free() when you're done with
   it.  */

struct dictionary *
dict_create_linear_expandable (void)
{
  struct dictionary *retval;

  retval = xmalloc (sizeof (struct dictionary));
  DICT_VECTOR (retval) = &dict_linear_expandable_vector;
  DICT_LINEAR_NSYMS (retval) = 0;
  DICT_LINEAR_EXPANDABLE_CAPACITY (retval)
    = DICT_EXPANDABLE_INITIAL_CAPACITY;
  DICT_LINEAR_SYMS (retval)
    = xmalloc (DICT_LINEAR_EXPANDABLE_CAPACITY (retval)
	       * sizeof (struct symbol *));

  return retval;
}

/* The functions providing the dictionary interface.  */

/* Free the memory used by a dictionary that's not on an obstack.  (If
   any.)  */

void
dict_free (struct dictionary *dict)
{
  (DICT_VECTOR (dict))->free (dict);
}

/* Add SYM to DICT.  DICT had better be expandable.  */

void
dict_add_symbol (struct dictionary *dict, struct symbol *sym)
{
  (DICT_VECTOR (dict))->add_symbol (dict, sym);
}

/* Initialize ITERATOR to point at the first symbol in DICT, and
   return that first symbol, or NULL if DICT is empty.  */

struct symbol *
dict_iterator_first (const struct dictionary *dict,
		     struct dict_iterator *iterator)
{
  return (DICT_VECTOR (dict))->iterator_first (dict, iterator);
}

/* Advance ITERATOR, and return the next symbol, or NULL if there are
   no more symbols.  */

struct symbol *
dict_iterator_next (struct dict_iterator *iterator)
{
  return (DICT_VECTOR (DICT_ITERATOR_DICT (iterator)))
    ->iterator_next (iterator);
}

struct symbol *
dict_iter_name_first (const struct dictionary *dict,
		      const char *name,
		      struct dict_iterator *iterator)
{
  return (DICT_VECTOR (dict))->iter_name_first (dict, name, iterator);
}

struct symbol *
dict_iter_name_next (const char *name, struct dict_iterator *iterator)
{
  return (DICT_VECTOR (DICT_ITERATOR_DICT (iterator)))
    ->iter_name_next (name, iterator);
}

int
dict_size (const struct dictionary *dict)
{
  return (DICT_VECTOR (dict))->size (dict);
}
 
/* Now come functions (well, one function, currently) that are
   implemented generically by means of the vtable.  Typically, they're
   rarely used.  */

/* Test to see if DICT is empty.  */

int
dict_empty (struct dictionary *dict)
{
  struct dict_iterator iter;

  return (dict_iterator_first (dict, &iter) == NULL);
}


/* The functions implementing the dictionary interface.  */

/* Generic functions, where appropriate.  */

static void
free_obstack (struct dictionary *dict)
{
  /* Do nothing!  */
}

static void
add_symbol_nonexpandable (struct dictionary *dict, struct symbol *sym)
{
  internal_error (__FILE__, __LINE__,
		  _("dict_add_symbol: non-expandable dictionary"));
}

/* Functions for DICT_HASHED and DICT_HASHED_EXPANDABLE.  */

static struct symbol *
iterator_first_hashed (const struct dictionary *dict,
		       struct dict_iterator *iterator)
{
  DICT_ITERATOR_DICT (iterator) = dict;
  DICT_ITERATOR_INDEX (iterator) = -1;
  return iterator_hashed_advance (iterator);
}

static struct symbol *
iterator_next_hashed (struct dict_iterator *iterator)
{
  const struct dictionary *dict = DICT_ITERATOR_DICT (iterator);
  struct symbol *next;

  next = DICT_ITERATOR_CURRENT (iterator)->hash_next;
  
  if (next == NULL)
    return iterator_hashed_advance (iterator);
  else
    {
      DICT_ITERATOR_CURRENT (iterator) = next;
      return next;
    }
}

static struct symbol *
iterator_hashed_advance (struct dict_iterator *iterator)
{
  const struct dictionary *dict = DICT_ITERATOR_DICT (iterator);
  int nbuckets = DICT_HASHED_NBUCKETS (dict);
  int i;

  for (i = DICT_ITERATOR_INDEX (iterator) + 1; i < nbuckets; ++i)
    {
      struct symbol *sym = DICT_HASHED_BUCKET (dict, i);
      
      if (sym != NULL)
	{
	  DICT_ITERATOR_INDEX (iterator) = i;
	  DICT_ITERATOR_CURRENT (iterator) = sym;
	  return sym;
	}
    }

  return NULL;
}

static struct symbol *
iter_name_first_hashed (const struct dictionary *dict,
			const char *name,
			struct dict_iterator *iterator)
{
  unsigned int hash_index
    = msymbol_hash_iw (name) % DICT_HASHED_NBUCKETS (dict);
  struct symbol *sym;

  DICT_ITERATOR_DICT (iterator) = dict;

  /* Loop through the symbols in the given bucket, breaking when SYM
     first matches.  If SYM never matches, it will be set to NULL;
     either way, we have the right return value.  */
  
  for (sym = DICT_HASHED_BUCKET (dict, hash_index);
       sym != NULL;
       sym = sym->hash_next)
    {
      /* Warning: the order of arguments to strcmp_iw matters!  */
      if (strcmp_iw (SYMBOL_SEARCH_NAME (sym), name) == 0)
	{
	  break;
	}
	
    }

  DICT_ITERATOR_CURRENT (iterator) = sym;
  return sym;
}

static struct symbol *
iter_name_next_hashed (const char *name, struct dict_iterator *iterator)
{
  struct symbol *next;

  for (next = DICT_ITERATOR_CURRENT (iterator)->hash_next;
       next != NULL;
       next = next->hash_next)
    {
      if (strcmp_iw (SYMBOL_SEARCH_NAME (next), name) == 0)
	break;
    }

  DICT_ITERATOR_CURRENT (iterator) = next;

  return next;
}

/* Insert SYM into DICT.  */

static void
insert_symbol_hashed (struct dictionary *dict,
		      struct symbol *sym)
{
  unsigned int hash_index;
  struct symbol **buckets = DICT_HASHED_BUCKETS (dict);

  hash_index = (msymbol_hash_iw (SYMBOL_SEARCH_NAME (sym))
		% DICT_HASHED_NBUCKETS (dict));
  sym->hash_next = buckets[hash_index];
  buckets[hash_index] = sym;
}

static int
size_hashed (const struct dictionary *dict)
{
  return DICT_HASHED_NBUCKETS (dict);
}

/* Functions only for DICT_HASHED_EXPANDABLE.  */

static void
free_hashed_expandable (struct dictionary *dict)
{
  xfree (DICT_HASHED_BUCKETS (dict));
  xfree (dict);
}

static void
add_symbol_hashed_expandable (struct dictionary *dict,
			      struct symbol *sym)
{
  int nsyms = ++DICT_HASHED_EXPANDABLE_NSYMS (dict);

  if (DICT_HASHTABLE_SIZE (nsyms) > DICT_HASHED_NBUCKETS (dict))
    expand_hashtable (dict);

  insert_symbol_hashed (dict, sym);
  DICT_HASHED_EXPANDABLE_NSYMS (dict) = nsyms;
}

static int
size_hashed_expandable (const struct dictionary *dict)
{
  return DICT_HASHED_EXPANDABLE_NSYMS (dict);
}

static void
expand_hashtable (struct dictionary *dict)
{
  int old_nbuckets = DICT_HASHED_NBUCKETS (dict);
  struct symbol **old_buckets = DICT_HASHED_BUCKETS (dict);
  int new_nbuckets = 2*old_nbuckets + 1;
  struct symbol **new_buckets = xcalloc (new_nbuckets,
					 sizeof (struct symbol *));
  int i;

  DICT_HASHED_NBUCKETS (dict) = new_nbuckets;
  DICT_HASHED_BUCKETS (dict) = new_buckets;

  for (i = 0; i < old_nbuckets; ++i) {
    struct symbol *sym, *next_sym;

    sym = old_buckets[i];
    if (sym != NULL) {
      for (next_sym = sym->hash_next;
	   next_sym != NULL;
	   next_sym = sym->hash_next) {
	insert_symbol_hashed (dict, sym);
	sym = next_sym;
      }

      insert_symbol_hashed (dict, sym);
    }
  }

  xfree (old_buckets);
}

/* Functions for DICT_LINEAR and DICT_LINEAR_EXPANDABLE.  */

static struct symbol *
iterator_first_linear (const struct dictionary *dict,
		       struct dict_iterator *iterator)
{
  DICT_ITERATOR_DICT (iterator) = dict;
  DICT_ITERATOR_INDEX (iterator) = 0;
  return DICT_LINEAR_NSYMS (dict) ? DICT_LINEAR_SYM (dict, 0) : NULL;
}

static struct symbol *
iterator_next_linear (struct dict_iterator *iterator)
{
  const struct dictionary *dict = DICT_ITERATOR_DICT (iterator);

  if (++DICT_ITERATOR_INDEX (iterator) >= DICT_LINEAR_NSYMS (dict))
    return NULL;
  else
    return DICT_LINEAR_SYM (dict, DICT_ITERATOR_INDEX (iterator));
}

static struct symbol *
iter_name_first_linear (const struct dictionary *dict,
			const char *name,
			struct dict_iterator *iterator)
{
  DICT_ITERATOR_DICT (iterator) = dict;
  DICT_ITERATOR_INDEX (iterator) = -1;

  return iter_name_next_linear (name, iterator);
}

static struct symbol *
iter_name_next_linear (const char *name, struct dict_iterator *iterator)
{
  const struct dictionary *dict = DICT_ITERATOR_DICT (iterator);
  int i, nsyms = DICT_LINEAR_NSYMS (dict);
  struct symbol *sym, *retval = NULL;

  for (i = DICT_ITERATOR_INDEX (iterator) + 1; i < nsyms; ++i)
    {
      sym = DICT_LINEAR_SYM (dict, i);
      if (strcmp_iw (SYMBOL_SEARCH_NAME (sym), name) == 0)
	{
	  retval = sym;
	  break;
	}
    }

  DICT_ITERATOR_INDEX (iterator) = i;
  
  return retval;
}

static int
size_linear (const struct dictionary *dict)
{
  return DICT_LINEAR_NSYMS (dict);
}

/* Functions only for DICT_LINEAR_EXPANDABLE.  */

static void
free_linear_expandable (struct dictionary *dict)
{
  xfree (DICT_LINEAR_SYMS (dict));
  xfree (dict);
}


static void
add_symbol_linear_expandable (struct dictionary *dict,
			      struct symbol *sym)
{
  int nsyms = ++DICT_LINEAR_NSYMS (dict);

  /* Do we have enough room?  If not, grow it.  */
  if (nsyms > DICT_LINEAR_EXPANDABLE_CAPACITY (dict)) {
    DICT_LINEAR_EXPANDABLE_CAPACITY (dict) *= 2;
    DICT_LINEAR_SYMS (dict)
      = xrealloc (DICT_LINEAR_SYMS (dict),
		  DICT_LINEAR_EXPANDABLE_CAPACITY (dict)
		  * sizeof (struct symbol *));
  }

  DICT_LINEAR_SYM (dict, nsyms - 1) = sym;
}