1 /* Implementation of the hash table lisp object type.
2 Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
3 Copyright (C) 1995, 1996 Ben Wing.
4 Copyright (C) 1997 Free Software Foundation, Inc.
6 This file is part of XEmacs.
8 XEmacs is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by the
10 Free Software Foundation; either version 2, or (at your option) any
13 XEmacs is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCNTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with XEmacs; see the file COPYING. If not, write to
20 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
23 /* Synched up with: Not in FSF. */
30 Lisp_Object Qhash_tablep;
31 static Lisp_Object Qhashtable, Qhash_table;
32 static Lisp_Object Qweakness, Qvalue, Qkey_or_value, Qkey_and_value;
33 static Lisp_Object Vall_weak_hash_tables;
34 static Lisp_Object Qrehash_size, Qrehash_threshold;
35 static Lisp_Object Q_size, Q_test, Q_weakness, Q_rehash_size, Q_rehash_threshold;
37 /* obsolete as of 19990901 in xemacs-21.2 */
38 static Lisp_Object Qweak, Qkey_weak, Qvalue_weak, Qkey_or_value_weak;
39 static Lisp_Object Qnon_weak, Q_type;
47 struct Lisp_Hash_Table
49 struct lcrecord_header header;
54 double rehash_threshold;
56 hash_table_hash_function_t hash_function;
57 hash_table_test_function_t test_function;
59 enum hash_table_weakness weakness;
60 Lisp_Object next_weak; /* Used to chain together all of the weak
61 hash tables. Don't mark through this. */
64 #define HENTRY_CLEAR_P(hentry) ((*(EMACS_UINT*)(&((hentry)->key))) == 0)
65 #define CLEAR_HENTRY(hentry) \
66 ((*(EMACS_UINT*)(&((hentry)->key))) = 0, \
67 (*(EMACS_UINT*)(&((hentry)->value))) = 0)
69 #define HASH_TABLE_DEFAULT_SIZE 16
70 #define HASH_TABLE_DEFAULT_REHASH_SIZE 1.3
71 #define HASH_TABLE_MIN_SIZE 10
73 #define HASH_CODE(key, ht) \
74 ((((ht)->hash_function ? (ht)->hash_function (key) : LISP_HASH (key)) \
75 * (ht)->golden_ratio) \
78 #define KEYS_EQUAL_P(key1, key2, testfun) \
79 (EQ (key1, key2) || ((testfun) && (testfun) (key1, key2)))
81 #define LINEAR_PROBING_LOOP(probe, entries, size) \
83 !HENTRY_CLEAR_P (probe) || \
84 (probe == entries + size ? \
85 (probe = entries, !HENTRY_CLEAR_P (probe)) : 0); \
88 #ifndef ERROR_CHECK_HASH_TABLE
89 # ifdef ERROR_CHECK_TYPECHECK
90 # define ERROR_CHECK_HASH_TABLE 1
92 # define ERROR_CHECK_HASH_TABLE 0
96 #if ERROR_CHECK_HASH_TABLE
98 check_hash_table_invariants (Lisp_Hash_Table *ht)
100 assert (ht->count < ht->size);
101 assert (ht->count <= ht->rehash_count);
102 assert (ht->rehash_count < ht->size);
103 assert ((double) ht->count * ht->rehash_threshold - 1 <= (double) ht->rehash_count);
104 assert (HENTRY_CLEAR_P (ht->hentries + ht->size));
107 #define check_hash_table_invariants(ht)
110 /* We use linear probing instead of double hashing, despite its lack
111 of blessing by Knuth and company, because, as a result of the
112 increasing discrepancy between CPU speeds and memory speeds, cache
113 behavior is becoming increasingly important, e.g:
115 For a trivial loop, the penalty for non-sequential access of an array is:
116 - a factor of 3-4 on Pentium Pro 200 Mhz
117 - a factor of 10 on Ultrasparc 300 Mhz */
119 /* Return a suitable size for a hash table, with at least SIZE slots. */
121 hash_table_size (size_t requested_size)
123 /* Return some prime near, but greater than or equal to, SIZE.
124 Decades from the time of writing, someone will have a system large
125 enough that the list below will be too short... */
126 static const size_t primes [] =
128 19, 29, 41, 59, 79, 107, 149, 197, 263, 347, 457, 599, 787, 1031,
129 1361, 1777, 2333, 3037, 3967, 5167, 6719, 8737, 11369, 14783,
130 19219, 24989, 32491, 42257, 54941, 71429, 92861, 120721, 156941,
131 204047, 265271, 344857, 448321, 582821, 757693, 985003, 1280519,
132 1664681, 2164111, 2813353, 3657361, 4754591, 6180989, 8035301,
133 10445899, 13579681, 17653589, 22949669, 29834603, 38784989,
134 50420551, 65546729, 85210757, 110774011, 144006217, 187208107,
135 243370577, 316381771, 411296309, 534685237, 695090819, 903618083,
136 1174703521, 1527114613, 1985248999, 2580823717UL, 3355070839UL
138 /* We've heard of binary search. */
140 for (low = 0, high = countof (primes) - 1; high - low > 1;)
142 /* Loop Invariant: size < primes [high] */
143 int mid = (low + high) / 2;
144 if (primes [mid] < requested_size)
149 return primes [high];
153 #if 0 /* I don't think these are needed any more.
154 If using the general lisp_object_equal_*() functions
155 causes efficiency problems, these can be resurrected. --ben */
156 /* equality and hash functions for Lisp strings */
158 lisp_string_equal (Lisp_Object str1, Lisp_Object str2)
160 /* This is wrong anyway. You can't use strcmp() on Lisp strings,
161 because they can contain zero characters. */
162 return !strcmp ((char *) XSTRING_DATA (str1), (char *) XSTRING_DATA (str2));
166 lisp_string_hash (Lisp_Object obj)
168 return hash_string (XSTRING_DATA (str), XSTRING_LENGTH (str));
174 lisp_object_eql_equal (Lisp_Object obj1, Lisp_Object obj2)
176 return EQ (obj1, obj2) || (FLOATP (obj1) && internal_equal (obj1, obj2, 0));
180 lisp_object_eql_hash (Lisp_Object obj)
182 return FLOATP (obj) ? internal_hash (obj, 0) : LISP_HASH (obj);
186 lisp_object_equal_equal (Lisp_Object obj1, Lisp_Object obj2)
188 return internal_equal (obj1, obj2, 0);
192 lisp_object_equal_hash (Lisp_Object obj)
194 return internal_hash (obj, 0);
199 mark_hash_table (Lisp_Object obj)
201 Lisp_Hash_Table *ht = XHASH_TABLE (obj);
203 /* If the hash table is weak, we don't want to mark the keys and
204 values (we scan over them after everything else has been marked,
205 and mark or remove them as necessary). */
206 if (ht->weakness == HASH_TABLE_NON_WEAK)
208 hentry *e, *sentinel;
210 for (e = ht->hentries, sentinel = e + ht->size; e < sentinel; e++)
211 if (!HENTRY_CLEAR_P (e))
213 mark_object (e->key);
214 mark_object (e->value);
220 /* Equality of hash tables. Two hash tables are equal when they are of
221 the same weakness and test function, they have the same number of
222 elements, and for each key in the hash table, the values are `equal'.
224 This is similar to Common Lisp `equalp' of hash tables, with the
225 difference that CL requires the keys to be compared with the test
226 function, which we don't do. Doing that would require consing, and
227 consing is a bad idea in `equal'. Anyway, our method should provide
228 the same result -- if the keys are not equal according to the test
229 function, then Fgethash() in hash_table_equal_mapper() will fail. */
231 hash_table_equal (Lisp_Object hash_table1, Lisp_Object hash_table2, int depth)
233 Lisp_Hash_Table *ht1 = XHASH_TABLE (hash_table1);
234 Lisp_Hash_Table *ht2 = XHASH_TABLE (hash_table2);
235 hentry *e, *sentinel;
237 if ((ht1->test_function != ht2->test_function) ||
238 (ht1->weakness != ht2->weakness) ||
239 (ht1->count != ht2->count))
244 for (e = ht1->hentries, sentinel = e + ht1->size; e < sentinel; e++)
245 if (!HENTRY_CLEAR_P (e))
246 /* Look up the key in the other hash table, and compare the values. */
248 Lisp_Object value_in_other = Fgethash (e->key, hash_table2, Qunbound);
249 if (UNBOUNDP (value_in_other) ||
250 !internal_equal (e->value, value_in_other, depth))
251 return 0; /* Give up */
257 /* This is not a great hash function, but it _is_ correct and fast.
258 Examining all entries is too expensive, and examining a random
259 subset does not yield a correct hash function. */
261 hash_table_hash (Lisp_Object hash_table, int depth)
263 return XHASH_TABLE (hash_table)->count;
267 /* Printing hash tables.
269 This is non-trivial, because we use a readable structure-style
270 syntax for hash tables. This means that a typical hash table will be
271 readably printed in the form of:
273 #s(hash-table size 2 data (key1 value1 key2 value2))
275 The supported hash table structure keywords and their values are:
276 `test' (eql (or nil), eq or equal)
277 `size' (a natnum or nil)
278 `rehash-size' (a float)
279 `rehash-threshold' (a float)
280 `weakness' (nil, key, value, key-and-value, or key-or-value)
283 If `print-readably' is nil, then a simpler syntax is used, for example
285 #<hash-table size 2/13 data (key1 value1 key2 value2) 0x874d>
287 The data is truncated to four pairs, and the rest is shown with
288 `...'. This printer does not cons. */
291 /* Print the data of the hash table. This maps through a Lisp
292 hash table and prints key/value pairs using PRINTCHARFUN. */
294 print_hash_table_data (Lisp_Hash_Table *ht, Lisp_Object printcharfun)
297 hentry *e, *sentinel;
299 write_c_string (" data (", printcharfun);
301 for (e = ht->hentries, sentinel = e + ht->size; e < sentinel; e++)
302 if (!HENTRY_CLEAR_P (e))
305 write_c_string (" ", printcharfun);
306 if (!print_readably && count > 3)
308 write_c_string ("...", printcharfun);
311 print_internal (e->key, printcharfun, 1);
312 write_c_string (" ", printcharfun);
313 print_internal (e->value, printcharfun, 1);
317 write_c_string (")", printcharfun);
321 print_hash_table (Lisp_Object obj, Lisp_Object printcharfun, int escapeflag)
323 Lisp_Hash_Table *ht = XHASH_TABLE (obj);
326 write_c_string (print_readably ? "#s(hash-table" : "#<hash-table",
329 /* These checks have a kludgy look to them, but they are safe.
330 Due to nature of hashing, you cannot use arbitrary
331 test functions anyway. */
332 if (!ht->test_function)
333 write_c_string (" test eq", printcharfun);
334 else if (ht->test_function == lisp_object_equal_equal)
335 write_c_string (" test equal", printcharfun);
336 else if (ht->test_function == lisp_object_eql_equal)
341 if (ht->count || !print_readably)
344 sprintf (buf, " size %lu", (unsigned long) ht->count);
346 sprintf (buf, " size %lu/%lu",
347 (unsigned long) ht->count,
348 (unsigned long) ht->size);
349 write_c_string (buf, printcharfun);
352 if (ht->weakness != HASH_TABLE_NON_WEAK)
354 sprintf (buf, " weakness %s",
355 (ht->weakness == HASH_TABLE_WEAK ? "key-and-value" :
356 ht->weakness == HASH_TABLE_KEY_WEAK ? "key" :
357 ht->weakness == HASH_TABLE_VALUE_WEAK ? "value" :
358 ht->weakness == HASH_TABLE_KEY_VALUE_WEAK ? "key-or-value" :
359 "you-d-better-not-see-this"));
360 write_c_string (buf, printcharfun);
364 print_hash_table_data (ht, printcharfun);
367 write_c_string (")", printcharfun);
370 sprintf (buf, " 0x%x>", ht->header.uid);
371 write_c_string (buf, printcharfun);
376 finalize_hash_table (void *header, int for_disksave)
380 Lisp_Hash_Table *ht = (Lisp_Hash_Table *) header;
382 xfree (ht->hentries);
387 static const struct lrecord_description hentry_description_1[] = {
388 { XD_LISP_OBJECT, offsetof (hentry, key) },
389 { XD_LISP_OBJECT, offsetof (hentry, value) },
393 static const struct struct_description hentry_description = {
398 const struct lrecord_description hash_table_description[] = {
399 { XD_SIZE_T, offsetof (Lisp_Hash_Table, size) },
400 { XD_STRUCT_PTR, offsetof (Lisp_Hash_Table, hentries), XD_INDIRECT(0, 1), &hentry_description },
401 { XD_LO_LINK, offsetof (Lisp_Hash_Table, next_weak) },
405 DEFINE_LRECORD_IMPLEMENTATION ("hash-table", hash_table,
406 mark_hash_table, print_hash_table,
408 hash_table_equal, hash_table_hash,
409 hash_table_description,
412 static Lisp_Hash_Table *
413 xhash_table (Lisp_Object hash_table)
416 CHECK_HASH_TABLE (hash_table);
417 check_hash_table_invariants (XHASH_TABLE (hash_table));
418 return XHASH_TABLE (hash_table);
422 /************************************************************************/
423 /* Creation of Hash Tables */
424 /************************************************************************/
426 /* Creation of hash tables, without error-checking. */
428 compute_hash_table_derived_values (Lisp_Hash_Table *ht)
430 ht->rehash_count = (size_t)
431 ((double) ht->size * ht->rehash_threshold);
432 ht->golden_ratio = (size_t)
433 ((double) ht->size * (.6180339887 / (double) sizeof (Lisp_Object)));
437 make_standard_lisp_hash_table (enum hash_table_test test,
440 double rehash_threshold,
441 enum hash_table_weakness weakness)
443 hash_table_hash_function_t hash_function = 0;
444 hash_table_test_function_t test_function = 0;
454 test_function = lisp_object_eql_equal;
455 hash_function = lisp_object_eql_hash;
458 case HASH_TABLE_EQUAL:
459 test_function = lisp_object_equal_equal;
460 hash_function = lisp_object_equal_hash;
467 return make_general_lisp_hash_table (hash_function, test_function,
468 size, rehash_size, rehash_threshold,
473 make_general_lisp_hash_table (hash_table_hash_function_t hash_function,
474 hash_table_test_function_t test_function,
477 double rehash_threshold,
478 enum hash_table_weakness weakness)
480 Lisp_Object hash_table;
481 Lisp_Hash_Table *ht = alloc_lcrecord_type (Lisp_Hash_Table, &lrecord_hash_table);
483 ht->test_function = test_function;
484 ht->hash_function = hash_function;
485 ht->weakness = weakness;
488 rehash_size > 1.0 ? rehash_size : HASH_TABLE_DEFAULT_REHASH_SIZE;
490 ht->rehash_threshold =
491 rehash_threshold > 0.0 ? rehash_threshold :
492 size > 4096 && !ht->test_function ? 0.7 : 0.6;
494 if (size < HASH_TABLE_MIN_SIZE)
495 size = HASH_TABLE_MIN_SIZE;
496 ht->size = hash_table_size ((size_t) (((double) size / ht->rehash_threshold)
500 compute_hash_table_derived_values (ht);
502 /* We leave room for one never-occupied sentinel hentry at the end. */
503 ht->hentries = xnew_array (hentry, ht->size + 1);
506 hentry *e, *sentinel;
507 for (e = ht->hentries, sentinel = e + ht->size; e <= sentinel; e++)
511 XSETHASH_TABLE (hash_table, ht);
513 if (weakness == HASH_TABLE_NON_WEAK)
514 ht->next_weak = Qunbound;
516 ht->next_weak = Vall_weak_hash_tables, Vall_weak_hash_tables = hash_table;
522 make_lisp_hash_table (size_t size,
523 enum hash_table_weakness weakness,
524 enum hash_table_test test)
526 return make_standard_lisp_hash_table (test, size, -1.0, -1.0, weakness);
529 /* Pretty reading of hash tables.
531 Here we use the existing structures mechanism (which is,
532 unfortunately, pretty cumbersome) for validating and instantiating
533 the hash tables. The idea is that the side-effect of reading a
534 #s(hash-table PLIST) object is creation of a hash table with desired
535 properties, and that the hash table is returned. */
537 /* Validation functions: each keyword provides its own validation
538 function. The errors should maybe be continuable, but it is
539 unclear how this would cope with ERRB. */
541 hash_table_size_validate (Lisp_Object keyword, Lisp_Object value,
547 maybe_signal_error (Qwrong_type_argument, list2 (Qnatnump, value),
553 decode_hash_table_size (Lisp_Object obj)
555 return NILP (obj) ? HASH_TABLE_DEFAULT_SIZE : XINT (obj);
559 hash_table_weakness_validate (Lisp_Object keyword, Lisp_Object value,
562 if (EQ (value, Qnil)) return 1;
563 if (EQ (value, Qt)) return 1;
564 if (EQ (value, Qkey)) return 1;
565 if (EQ (value, Qkey_and_value)) return 1;
566 if (EQ (value, Qkey_or_value)) return 1;
567 if (EQ (value, Qvalue)) return 1;
569 /* Following values are obsolete as of 19990901 in xemacs-21.2 */
570 if (EQ (value, Qnon_weak)) return 1;
571 if (EQ (value, Qweak)) return 1;
572 if (EQ (value, Qkey_weak)) return 1;
573 if (EQ (value, Qkey_or_value_weak)) return 1;
574 if (EQ (value, Qvalue_weak)) return 1;
576 maybe_signal_simple_error ("Invalid hash table weakness",
577 value, Qhash_table, errb);
581 static enum hash_table_weakness
582 decode_hash_table_weakness (Lisp_Object obj)
584 if (EQ (obj, Qnil)) return HASH_TABLE_NON_WEAK;
585 if (EQ (obj, Qt)) return HASH_TABLE_WEAK;
586 if (EQ (obj, Qkey_and_value)) return HASH_TABLE_WEAK;
587 if (EQ (obj, Qkey)) return HASH_TABLE_KEY_WEAK;
588 if (EQ (obj, Qkey_or_value)) return HASH_TABLE_KEY_VALUE_WEAK;
589 if (EQ (obj, Qvalue)) return HASH_TABLE_VALUE_WEAK;
591 /* Following values are obsolete as of 19990901 in xemacs-21.2 */
592 if (EQ (obj, Qnon_weak)) return HASH_TABLE_NON_WEAK;
593 if (EQ (obj, Qweak)) return HASH_TABLE_WEAK;
594 if (EQ (obj, Qkey_weak)) return HASH_TABLE_KEY_WEAK;
595 if (EQ (obj, Qkey_or_value_weak)) return HASH_TABLE_KEY_VALUE_WEAK;
596 if (EQ (obj, Qvalue_weak)) return HASH_TABLE_VALUE_WEAK;
598 signal_simple_error ("Invalid hash table weakness", obj);
599 return HASH_TABLE_NON_WEAK; /* not reached */
603 hash_table_test_validate (Lisp_Object keyword, Lisp_Object value,
606 if (EQ (value, Qnil)) return 1;
607 if (EQ (value, Qeq)) return 1;
608 if (EQ (value, Qequal)) return 1;
609 if (EQ (value, Qeql)) return 1;
611 maybe_signal_simple_error ("Invalid hash table test",
612 value, Qhash_table, errb);
616 static enum hash_table_test
617 decode_hash_table_test (Lisp_Object obj)
619 if (EQ (obj, Qnil)) return HASH_TABLE_EQL;
620 if (EQ (obj, Qeq)) return HASH_TABLE_EQ;
621 if (EQ (obj, Qequal)) return HASH_TABLE_EQUAL;
622 if (EQ (obj, Qeql)) return HASH_TABLE_EQL;
624 signal_simple_error ("Invalid hash table test", obj);
625 return HASH_TABLE_EQ; /* not reached */
629 hash_table_rehash_size_validate (Lisp_Object keyword, Lisp_Object value,
634 maybe_signal_error (Qwrong_type_argument, list2 (Qfloatp, value),
640 double rehash_size = XFLOAT_DATA (value);
641 if (rehash_size <= 1.0)
643 maybe_signal_simple_error
644 ("Hash table rehash size must be greater than 1.0",
645 value, Qhash_table, errb);
654 decode_hash_table_rehash_size (Lisp_Object rehash_size)
656 return NILP (rehash_size) ? -1.0 : XFLOAT_DATA (rehash_size);
660 hash_table_rehash_threshold_validate (Lisp_Object keyword, Lisp_Object value,
665 maybe_signal_error (Qwrong_type_argument, list2 (Qfloatp, value),
671 double rehash_threshold = XFLOAT_DATA (value);
672 if (rehash_threshold <= 0.0 || rehash_threshold >= 1.0)
674 maybe_signal_simple_error
675 ("Hash table rehash threshold must be between 0.0 and 1.0",
676 value, Qhash_table, errb);
685 decode_hash_table_rehash_threshold (Lisp_Object rehash_threshold)
687 return NILP (rehash_threshold) ? -1.0 : XFLOAT_DATA (rehash_threshold);
691 hash_table_data_validate (Lisp_Object keyword, Lisp_Object value,
696 GET_EXTERNAL_LIST_LENGTH (value, len);
700 maybe_signal_simple_error
701 ("Hash table data must have alternating key/value pairs",
702 value, Qhash_table, errb);
708 /* The actual instantiation of a hash table. This does practically no
709 error checking, because it relies on the fact that the paranoid
710 functions above have error-checked everything to the last details.
711 If this assumption is wrong, we will get a crash immediately (with
712 error-checking compiled in), and we'll know if there is a bug in
713 the structure mechanism. So there. */
715 hash_table_instantiate (Lisp_Object plist)
717 Lisp_Object hash_table;
718 Lisp_Object test = Qnil;
719 Lisp_Object size = Qnil;
720 Lisp_Object rehash_size = Qnil;
721 Lisp_Object rehash_threshold = Qnil;
722 Lisp_Object weakness = Qnil;
723 Lisp_Object data = Qnil;
725 while (!NILP (plist))
727 Lisp_Object key, value;
728 key = XCAR (plist); plist = XCDR (plist);
729 value = XCAR (plist); plist = XCDR (plist);
731 if (EQ (key, Qtest)) test = value;
732 else if (EQ (key, Qsize)) size = value;
733 else if (EQ (key, Qrehash_size)) rehash_size = value;
734 else if (EQ (key, Qrehash_threshold)) rehash_threshold = value;
735 else if (EQ (key, Qweakness)) weakness = value;
736 else if (EQ (key, Qdata)) data = value;
737 else if (EQ (key, Qtype))/*obsolete*/ weakness = value;
742 /* Create the hash table. */
743 hash_table = make_standard_lisp_hash_table
744 (decode_hash_table_test (test),
745 decode_hash_table_size (size),
746 decode_hash_table_rehash_size (rehash_size),
747 decode_hash_table_rehash_threshold (rehash_threshold),
748 decode_hash_table_weakness (weakness));
750 /* I'm not sure whether this can GC, but better safe than sorry. */
755 /* And fill it with data. */
758 Lisp_Object key, value;
759 key = XCAR (data); data = XCDR (data);
760 value = XCAR (data); data = XCDR (data);
761 Fputhash (key, value, hash_table);
770 structure_type_create_hash_table_structure_name (Lisp_Object structure_name)
772 struct structure_type *st;
774 st = define_structure_type (structure_name, 0, hash_table_instantiate);
775 define_structure_type_keyword (st, Qtest, hash_table_test_validate);
776 define_structure_type_keyword (st, Qsize, hash_table_size_validate);
777 define_structure_type_keyword (st, Qrehash_size, hash_table_rehash_size_validate);
778 define_structure_type_keyword (st, Qrehash_threshold, hash_table_rehash_threshold_validate);
779 define_structure_type_keyword (st, Qweakness, hash_table_weakness_validate);
780 define_structure_type_keyword (st, Qdata, hash_table_data_validate);
782 /* obsolete as of 19990901 in xemacs-21.2 */
783 define_structure_type_keyword (st, Qtype, hash_table_weakness_validate);
786 /* Create a built-in Lisp structure type named `hash-table'.
787 We make #s(hashtable ...) equivalent to #s(hash-table ...),
788 for backward compatibility.
789 This is called from emacs.c. */
791 structure_type_create_hash_table (void)
793 structure_type_create_hash_table_structure_name (Qhash_table);
794 structure_type_create_hash_table_structure_name (Qhashtable); /* compat */
798 /************************************************************************/
799 /* Definition of Lisp-visible methods */
800 /************************************************************************/
802 DEFUN ("hash-table-p", Fhash_table_p, 1, 1, 0, /*
803 Return t if OBJECT is a hash table, else nil.
807 return HASH_TABLEP (object) ? Qt : Qnil;
810 DEFUN ("make-hash-table", Fmake_hash_table, 0, MANY, 0, /*
811 Return a new empty hash table object.
812 Use Common Lisp style keywords to specify hash table properties.
813 (make-hash-table &key test size rehash-size rehash-threshold weakness)
815 Keyword :test can be `eq', `eql' (default) or `equal'.
816 Comparison between keys is done using this function.
817 If speed is important, consider using `eq'.
818 When storing strings in the hash table, you will likely need to use `equal'.
820 Keyword :size specifies the number of keys likely to be inserted.
821 This number of entries can be inserted without enlarging the hash table.
823 Keyword :rehash-size must be a float greater than 1.0, and specifies
824 the factor by which to increase the size of the hash table when enlarging.
826 Keyword :rehash-threshold must be a float between 0.0 and 1.0,
827 and specifies the load factor of the hash table which triggers enlarging.
829 Non-standard keyword :weakness can be `nil' (default), `t', `key-and-value',
830 `key', `value' or `key-or-value'. `t' is an alias for `key-and-value'.
832 A key-and-value-weak hash table, also known as a fully-weak or simply
833 as a weak hash table, is one whose pointers do not count as GC
834 referents: for any key-value pair in the hash table, if the only
835 remaining pointer to either the key or the value is in a weak hash
836 table, then the pair will be removed from the hash table, and the key
837 and value collected. A non-weak hash table (or any other pointer)
838 would prevent the object from being collected.
840 A key-weak hash table is similar to a fully-weak hash table except that
841 a key-value pair will be removed only if the key remains unmarked
842 outside of weak hash tables. The pair will remain in the hash table if
843 the key is pointed to by something other than a weak hash table, even
846 A value-weak hash table is similar to a fully-weak hash table except
847 that a key-value pair will be removed only if the value remains
848 unmarked outside of weak hash tables. The pair will remain in the
849 hash table if the value is pointed to by something other than a weak
850 hash table, even if the key is not.
852 A key-or-value-weak hash table is similar to a fully-weak hash table except
853 that a key-value pair will be removed only if the value and the key remain
854 unmarked outside of weak hash tables. The pair will remain in the
855 hash table if the value or key are pointed to by something other than a weak
856 hash table, even if the other is not.
858 (int nargs, Lisp_Object *args))
861 Lisp_Object test = Qnil;
862 Lisp_Object size = Qnil;
863 Lisp_Object rehash_size = Qnil;
864 Lisp_Object rehash_threshold = Qnil;
865 Lisp_Object weakness = Qnil;
867 while (i + 1 < nargs)
869 Lisp_Object keyword = args[i++];
870 Lisp_Object value = args[i++];
872 if (EQ (keyword, Q_test)) test = value;
873 else if (EQ (keyword, Q_size)) size = value;
874 else if (EQ (keyword, Q_rehash_size)) rehash_size = value;
875 else if (EQ (keyword, Q_rehash_threshold)) rehash_threshold = value;
876 else if (EQ (keyword, Q_weakness)) weakness = value;
877 else if (EQ (keyword, Q_type))/*obsolete*/ weakness = value;
878 else signal_simple_error ("Invalid hash table property keyword", keyword);
882 signal_simple_error ("Hash table property requires a value", args[i]);
884 #define VALIDATE_VAR(var) \
885 if (!NILP (var)) hash_table_##var##_validate (Q##var, var, ERROR_ME);
889 VALIDATE_VAR (rehash_size);
890 VALIDATE_VAR (rehash_threshold);
891 VALIDATE_VAR (weakness);
893 return make_standard_lisp_hash_table
894 (decode_hash_table_test (test),
895 decode_hash_table_size (size),
896 decode_hash_table_rehash_size (rehash_size),
897 decode_hash_table_rehash_threshold (rehash_threshold),
898 decode_hash_table_weakness (weakness));
901 DEFUN ("copy-hash-table", Fcopy_hash_table, 1, 1, 0, /*
902 Return a new hash table containing the same keys and values as HASH-TABLE.
903 The keys and values will not themselves be copied.
907 const Lisp_Hash_Table *ht_old = xhash_table (hash_table);
908 Lisp_Hash_Table *ht = alloc_lcrecord_type (Lisp_Hash_Table, &lrecord_hash_table);
910 copy_lcrecord (ht, ht_old);
912 ht->hentries = xnew_array (hentry, ht_old->size + 1);
913 memcpy (ht->hentries, ht_old->hentries, (ht_old->size + 1) * sizeof (hentry));
915 XSETHASH_TABLE (hash_table, ht);
917 if (! EQ (ht->next_weak, Qunbound))
919 ht->next_weak = Vall_weak_hash_tables;
920 Vall_weak_hash_tables = hash_table;
927 resize_hash_table (Lisp_Hash_Table *ht, size_t new_size)
929 hentry *old_entries, *new_entries, *sentinel, *e;
935 old_entries = ht->hentries;
937 ht->hentries = xnew_array_and_zero (hentry, new_size + 1);
938 new_entries = ht->hentries;
940 compute_hash_table_derived_values (ht);
942 for (e = old_entries, sentinel = e + old_size; e < sentinel; e++)
943 if (!HENTRY_CLEAR_P (e))
945 hentry *probe = new_entries + HASH_CODE (e->key, ht);
946 LINEAR_PROBING_LOOP (probe, new_entries, new_size)
951 if (!DUMPEDP (old_entries))
955 /* After a hash table has been saved to disk and later restored by the
956 portable dumper, it contains the same objects, but their addresses
957 and thus their HASH_CODEs have changed. */
959 pdump_reorganize_hash_table (Lisp_Object hash_table)
961 const Lisp_Hash_Table *ht = xhash_table (hash_table);
962 hentry *new_entries = xnew_array_and_zero (hentry, ht->size + 1);
963 hentry *e, *sentinel;
965 for (e = ht->hentries, sentinel = e + ht->size; e < sentinel; e++)
966 if (!HENTRY_CLEAR_P (e))
968 hentry *probe = new_entries + HASH_CODE (e->key, ht);
969 LINEAR_PROBING_LOOP (probe, new_entries, ht->size)
974 memcpy (ht->hentries, new_entries, ht->size * sizeof (hentry));
980 enlarge_hash_table (Lisp_Hash_Table *ht)
983 hash_table_size ((size_t) ((double) ht->size * ht->rehash_size));
984 resize_hash_table (ht, new_size);
988 find_hentry (Lisp_Object key, const Lisp_Hash_Table *ht)
990 hash_table_test_function_t test_function = ht->test_function;
991 hentry *entries = ht->hentries;
992 hentry *probe = entries + HASH_CODE (key, ht);
994 LINEAR_PROBING_LOOP (probe, entries, ht->size)
995 if (KEYS_EQUAL_P (probe->key, key, test_function))
1001 DEFUN ("gethash", Fgethash, 2, 3, 0, /*
1002 Find hash value for KEY in HASH-TABLE.
1003 If there is no corresponding value, return DEFAULT (which defaults to nil).
1005 (key, hash_table, default_))
1007 const Lisp_Hash_Table *ht = xhash_table (hash_table);
1008 hentry *e = find_hentry (key, ht);
1010 return HENTRY_CLEAR_P (e) ? default_ : e->value;
1013 DEFUN ("puthash", Fputhash, 3, 3, 0, /*
1014 Hash KEY to VALUE in HASH-TABLE.
1016 (key, value, hash_table))
1018 Lisp_Hash_Table *ht = xhash_table (hash_table);
1019 hentry *e = find_hentry (key, ht);
1021 if (!HENTRY_CLEAR_P (e))
1022 return e->value = value;
1027 if (++ht->count >= ht->rehash_count)
1028 enlarge_hash_table (ht);
1033 /* Remove hentry pointed at by PROBE.
1034 Subsequent entries are removed and reinserted.
1035 We don't use tombstones - too wasteful. */
1037 remhash_1 (Lisp_Hash_Table *ht, hentry *entries, hentry *probe)
1039 size_t size = ht->size;
1040 CLEAR_HENTRY (probe);
1044 LINEAR_PROBING_LOOP (probe, entries, size)
1046 Lisp_Object key = probe->key;
1047 hentry *probe2 = entries + HASH_CODE (key, ht);
1048 LINEAR_PROBING_LOOP (probe2, entries, size)
1049 if (EQ (probe2->key, key))
1050 /* hentry at probe doesn't need to move. */
1051 goto continue_outer_loop;
1052 /* Move hentry from probe to new home at probe2. */
1054 CLEAR_HENTRY (probe);
1055 continue_outer_loop: continue;
1059 DEFUN ("remhash", Fremhash, 2, 2, 0, /*
1060 Remove the entry for KEY from HASH-TABLE.
1061 Do nothing if there is no entry for KEY in HASH-TABLE.
1065 Lisp_Hash_Table *ht = xhash_table (hash_table);
1066 hentry *e = find_hentry (key, ht);
1068 if (HENTRY_CLEAR_P (e))
1071 remhash_1 (ht, ht->hentries, e);
1075 DEFUN ("clrhash", Fclrhash, 1, 1, 0, /*
1076 Remove all entries from HASH-TABLE, leaving it empty.
1080 Lisp_Hash_Table *ht = xhash_table (hash_table);
1081 hentry *e, *sentinel;
1083 for (e = ht->hentries, sentinel = e + ht->size; e < sentinel; e++)
1090 /************************************************************************/
1091 /* Accessor Functions */
1092 /************************************************************************/
1094 DEFUN ("hash-table-count", Fhash_table_count, 1, 1, 0, /*
1095 Return the number of entries in HASH-TABLE.
1099 return make_int (xhash_table (hash_table)->count);
1102 DEFUN ("hash-table-test", Fhash_table_test, 1, 1, 0, /*
1103 Return the test function of HASH-TABLE.
1104 This can be one of `eq', `eql' or `equal'.
1108 hash_table_test_function_t fun = xhash_table (hash_table)->test_function;
1110 return (fun == lisp_object_eql_equal ? Qeql :
1111 fun == lisp_object_equal_equal ? Qequal :
1115 DEFUN ("hash-table-size", Fhash_table_size, 1, 1, 0, /*
1116 Return the size of HASH-TABLE.
1117 This is the current number of slots in HASH-TABLE, whether occupied or not.
1121 return make_int (xhash_table (hash_table)->size);
1124 DEFUN ("hash-table-rehash-size", Fhash_table_rehash_size, 1, 1, 0, /*
1125 Return the current rehash size of HASH-TABLE.
1126 This is a float greater than 1.0; the factor by which HASH-TABLE
1127 is enlarged when the rehash threshold is exceeded.
1131 return make_float (xhash_table (hash_table)->rehash_size);
1134 DEFUN ("hash-table-rehash-threshold", Fhash_table_rehash_threshold, 1, 1, 0, /*
1135 Return the current rehash threshold of HASH-TABLE.
1136 This is a float between 0.0 and 1.0; the maximum `load factor' of HASH-TABLE,
1137 beyond which the HASH-TABLE is enlarged by rehashing.
1141 return make_float (xhash_table (hash_table)->rehash_threshold);
1144 DEFUN ("hash-table-weakness", Fhash_table_weakness, 1, 1, 0, /*
1145 Return the weakness of HASH-TABLE.
1146 This can be one of `nil', `key-and-value', `key-or-value', `key' or `value'.
1150 switch (xhash_table (hash_table)->weakness)
1152 case HASH_TABLE_WEAK: return Qkey_and_value;
1153 case HASH_TABLE_KEY_WEAK: return Qkey;
1154 case HASH_TABLE_KEY_VALUE_WEAK: return Qkey_or_value;
1155 case HASH_TABLE_VALUE_WEAK: return Qvalue;
1156 default: return Qnil;
1160 /* obsolete as of 19990901 in xemacs-21.2 */
1161 DEFUN ("hash-table-type", Fhash_table_type, 1, 1, 0, /*
1162 Return the type of HASH-TABLE.
1163 This can be one of `non-weak', `weak', `key-weak' or `value-weak'.
1167 switch (xhash_table (hash_table)->weakness)
1169 case HASH_TABLE_WEAK: return Qweak;
1170 case HASH_TABLE_KEY_WEAK: return Qkey_weak;
1171 case HASH_TABLE_KEY_VALUE_WEAK: return Qkey_or_value_weak;
1172 case HASH_TABLE_VALUE_WEAK: return Qvalue_weak;
1173 default: return Qnon_weak;
1177 /************************************************************************/
1178 /* Mapping Functions */
1179 /************************************************************************/
1180 DEFUN ("maphash", Fmaphash, 2, 2, 0, /*
1181 Map FUNCTION over entries in HASH-TABLE, calling it with two args,
1182 each key and value in HASH-TABLE.
1184 FUNCTION may not modify HASH-TABLE, with the one exception that FUNCTION
1185 may remhash or puthash the entry currently being processed by FUNCTION.
1187 (function, hash_table))
1189 const Lisp_Hash_Table *ht = xhash_table (hash_table);
1190 const hentry *e, *sentinel;
1192 for (e = ht->hentries, sentinel = e + ht->size; e < sentinel; e++)
1193 if (!HENTRY_CLEAR_P (e))
1195 Lisp_Object args[3], key;
1201 Ffuncall (countof (args), args);
1202 /* Has FUNCTION done a remhash? */
1203 if (!EQ (key, e->key) && !HENTRY_CLEAR_P (e))
1210 /* Map *C* function FUNCTION over the elements of a lisp hash table. */
1212 elisp_maphash (maphash_function_t function,
1213 Lisp_Object hash_table, void *extra_arg)
1215 const Lisp_Hash_Table *ht = XHASH_TABLE (hash_table);
1216 const hentry *e, *sentinel;
1218 for (e = ht->hentries, sentinel = e + ht->size; e < sentinel; e++)
1219 if (!HENTRY_CLEAR_P (e))
1224 if (function (key, e->value, extra_arg))
1226 /* Has FUNCTION done a remhash? */
1227 if (!EQ (key, e->key) && !HENTRY_CLEAR_P (e))
1232 /* Remove all elements of a lisp hash table satisfying *C* predicate PREDICATE. */
1234 elisp_map_remhash (maphash_function_t predicate,
1235 Lisp_Object hash_table, void *extra_arg)
1237 Lisp_Hash_Table *ht = XHASH_TABLE (hash_table);
1238 hentry *e, *entries, *sentinel;
1240 for (e = entries = ht->hentries, sentinel = e + ht->size; e < sentinel; e++)
1241 if (!HENTRY_CLEAR_P (e))
1244 if (predicate (e->key, e->value, extra_arg))
1246 remhash_1 (ht, entries, e);
1247 if (!HENTRY_CLEAR_P (e))
1254 /************************************************************************/
1255 /* garbage collecting weak hash tables */
1256 /************************************************************************/
1257 #define MARK_OBJ(obj) do { \
1258 Lisp_Object mo_obj = (obj); \
1259 if (!marked_p (mo_obj)) \
1261 mark_object (mo_obj); \
1267 /* Complete the marking for semi-weak hash tables. */
1269 finish_marking_weak_hash_tables (void)
1271 Lisp_Object hash_table;
1274 for (hash_table = Vall_weak_hash_tables;
1276 hash_table = XHASH_TABLE (hash_table)->next_weak)
1278 const Lisp_Hash_Table *ht = XHASH_TABLE (hash_table);
1279 const hentry *e = ht->hentries;
1280 const hentry *sentinel = e + ht->size;
1282 if (! marked_p (hash_table))
1283 /* The hash table is probably garbage. Ignore it. */
1286 /* Now, scan over all the pairs. For all pairs that are
1287 half-marked, we may need to mark the other half if we're
1288 keeping this pair. */
1289 switch (ht->weakness)
1291 case HASH_TABLE_KEY_WEAK:
1292 for (; e < sentinel; e++)
1293 if (!HENTRY_CLEAR_P (e))
1294 if (marked_p (e->key))
1295 MARK_OBJ (e->value);
1298 case HASH_TABLE_VALUE_WEAK:
1299 for (; e < sentinel; e++)
1300 if (!HENTRY_CLEAR_P (e))
1301 if (marked_p (e->value))
1305 case HASH_TABLE_KEY_VALUE_WEAK:
1306 for (; e < sentinel; e++)
1307 if (!HENTRY_CLEAR_P (e))
1309 if (marked_p (e->value))
1311 else if (marked_p (e->key))
1312 MARK_OBJ (e->value);
1316 case HASH_TABLE_KEY_CAR_WEAK:
1317 for (; e < sentinel; e++)
1318 if (!HENTRY_CLEAR_P (e))
1319 if (!CONSP (e->key) || marked_p (XCAR (e->key)))
1322 MARK_OBJ (e->value);
1326 /* We seem to be sprouting new weakness types at an alarming
1327 rate. At least this is not externally visible - and in
1328 fact all of these KEY_CAR_* types are only used by the
1330 case HASH_TABLE_KEY_CAR_VALUE_WEAK:
1331 for (; e < sentinel; e++)
1332 if (!HENTRY_CLEAR_P (e))
1334 if (!CONSP (e->key) || marked_p (XCAR (e->key)))
1337 MARK_OBJ (e->value);
1339 else if (marked_p (e->value))
1344 case HASH_TABLE_VALUE_CAR_WEAK:
1345 for (; e < sentinel; e++)
1346 if (!HENTRY_CLEAR_P (e))
1347 if (!CONSP (e->value) || marked_p (XCAR (e->value)))
1350 MARK_OBJ (e->value);
1363 prune_weak_hash_tables (void)
1365 Lisp_Object hash_table, prev = Qnil;
1366 for (hash_table = Vall_weak_hash_tables;
1368 hash_table = XHASH_TABLE (hash_table)->next_weak)
1370 if (! marked_p (hash_table))
1372 /* This hash table itself is garbage. Remove it from the list. */
1374 Vall_weak_hash_tables = XHASH_TABLE (hash_table)->next_weak;
1376 XHASH_TABLE (prev)->next_weak = XHASH_TABLE (hash_table)->next_weak;
1380 /* Now, scan over all the pairs. Remove all of the pairs
1381 in which the key or value, or both, is unmarked
1382 (depending on the weakness of the hash table). */
1383 Lisp_Hash_Table *ht = XHASH_TABLE (hash_table);
1384 hentry *entries = ht->hentries;
1385 hentry *sentinel = entries + ht->size;
1388 for (e = entries; e < sentinel; e++)
1389 if (!HENTRY_CLEAR_P (e))
1392 if (!marked_p (e->key) || !marked_p (e->value))
1394 remhash_1 (ht, entries, e);
1395 if (!HENTRY_CLEAR_P (e))
1405 /* Return a hash value for an array of Lisp_Objects of size SIZE. */
1408 internal_array_hash (Lisp_Object *arr, int size, int depth)
1411 hashcode_t hash = 0;
1416 for (i = 0; i < size; i++)
1417 hash = HASH2 (hash, internal_hash (arr[i], depth));
1421 /* just pick five elements scattered throughout the array.
1422 A slightly better approach would be to offset by some
1423 noise factor from the points chosen below. */
1424 for (i = 0; i < 5; i++)
1425 hash = HASH2 (hash, internal_hash (arr[i*size/5], depth));
1430 /* Return a hash value for a Lisp_Object. This is for use when hashing
1431 objects with the comparison being `equal' (for `eq', you can just
1432 use the Lisp_Object itself as the hash value). You need to make a
1433 tradeoff between the speed of the hash function and how good the
1434 hashing is. In particular, the hash function needs to be FAST,
1435 so you can't just traipse down the whole tree hashing everything
1436 together. Most of the time, objects will differ in the first
1437 few elements you hash. Thus, we only go to a short depth (5)
1438 and only hash at most 5 elements out of a vector. Theoretically
1439 we could still take 5^5 time (a big big number) to compute a
1440 hash, but practically this won't ever happen. */
1443 internal_hash (Lisp_Object obj, int depth)
1449 /* no point in worrying about tail recursion, since we're not
1451 return HASH2 (internal_hash (XCAR (obj), depth + 1),
1452 internal_hash (XCDR (obj), depth + 1));
1456 return hash_string (XSTRING_DATA (obj), XSTRING_LENGTH (obj));
1460 const struct lrecord_implementation
1461 *imp = XRECORD_LHEADER_IMPLEMENTATION (obj);
1463 return imp->hash (obj, depth);
1466 return LISP_HASH (obj);
1469 DEFUN ("sxhash", Fsxhash, 1, 1, 0, /*
1470 Return a hash value for OBJECT.
1471 \(equal obj1 obj2) implies (= (sxhash obj1) (sxhash obj2)).
1475 return make_int (internal_hash (object, 0));
1479 xxDEFUN ("internal-hash-value", Finternal_hash_value, 1, 1, 0, /*
1480 Hash value of OBJECT. For debugging.
1481 The value is returned as (HIGH . LOW).
1485 /* This function is pretty 32bit-centric. */
1486 hashcode_t hash = internal_hash (object, 0);
1487 return Fcons (hash >> 16, hash & 0xffff);
1492 /************************************************************************/
1493 /* initialization */
1494 /************************************************************************/
1497 syms_of_elhash (void)
1499 INIT_LRECORD_IMPLEMENTATION (hash_table);
1501 DEFSUBR (Fhash_table_p);
1502 DEFSUBR (Fmake_hash_table);
1503 DEFSUBR (Fcopy_hash_table);
1509 DEFSUBR (Fhash_table_count);
1510 DEFSUBR (Fhash_table_test);
1511 DEFSUBR (Fhash_table_size);
1512 DEFSUBR (Fhash_table_rehash_size);
1513 DEFSUBR (Fhash_table_rehash_threshold);
1514 DEFSUBR (Fhash_table_weakness);
1515 DEFSUBR (Fhash_table_type); /* obsolete */
1518 DEFSUBR (Finternal_hash_value);
1521 defsymbol (&Qhash_tablep, "hash-table-p");
1522 defsymbol (&Qhash_table, "hash-table");
1523 defsymbol (&Qhashtable, "hashtable");
1524 defsymbol (&Qweakness, "weakness");
1525 defsymbol (&Qvalue, "value");
1526 defsymbol (&Qkey_or_value, "key-or-value");
1527 defsymbol (&Qkey_and_value, "key-and-value");
1528 defsymbol (&Qrehash_size, "rehash-size");
1529 defsymbol (&Qrehash_threshold, "rehash-threshold");
1531 defsymbol (&Qweak, "weak"); /* obsolete */
1532 defsymbol (&Qkey_weak, "key-weak"); /* obsolete */
1533 defsymbol (&Qkey_or_value_weak, "key-or-value-weak"); /* obsolete */
1534 defsymbol (&Qvalue_weak, "value-weak"); /* obsolete */
1535 defsymbol (&Qnon_weak, "non-weak"); /* obsolete */
1537 defkeyword (&Q_test, ":test");
1538 defkeyword (&Q_size, ":size");
1539 defkeyword (&Q_rehash_size, ":rehash-size");
1540 defkeyword (&Q_rehash_threshold, ":rehash-threshold");
1541 defkeyword (&Q_weakness, ":weakness");
1542 defkeyword (&Q_type, ":type"); /* obsolete */
1546 vars_of_elhash (void)
1548 /* This must NOT be staticpro'd */
1549 Vall_weak_hash_tables = Qnil;
1550 dump_add_weak_object_chain (&Vall_weak_hash_tables);