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6922d92f | 1 | /* Copyright (C) 1995, 1996, 1998, 2000, 2001, 2003, 2006, 2008, 2009, 2010, |
1e3fd6a0 | 2 | * 2011, 2012, 2014 Free Software Foundation, Inc. |
6922d92f | 3 | * |
d3cf93bc | 4 | * This library is free software; you can redistribute it and/or |
53befeb7 NJ |
5 | * modify it under the terms of the GNU Lesser General Public License |
6 | * as published by the Free Software Foundation; either version 3 of | |
7 | * the License, or (at your option) any later version. | |
0f2d19dd | 8 | * |
53befeb7 NJ |
9 | * This library is distributed in the hope that it will be useful, but |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
d3cf93bc NJ |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | * Lesser General Public License for more details. | |
0f2d19dd | 13 | * |
d3cf93bc NJ |
14 | * You should have received a copy of the GNU Lesser General Public |
15 | * License along with this library; if not, write to the Free Software | |
53befeb7 NJ |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
17 | * 02110-1301 USA | |
d3cf93bc | 18 | */ |
1bbd0b84 | 19 | |
1bbd0b84 | 20 | |
0f2d19dd | 21 | \f |
dbb605f5 LC |
22 | #ifdef HAVE_CONFIG_H |
23 | # include <config.h> | |
24 | #endif | |
592996c9 | 25 | |
06c1d900 MV |
26 | #include <stdio.h> |
27 | ||
a0599745 MD |
28 | #include "libguile/_scm.h" |
29 | #include "libguile/vectors.h" | |
f59a096e | 30 | #include "libguile/hashtab.h" |
0f2d19dd | 31 | |
a0599745 MD |
32 | #include "libguile/validate.h" |
33 | #include "libguile/weaks.h" | |
0f2d19dd | 34 | |
1c44468d | 35 | #include "libguile/bdw-gc.h" |
986ec822 LC |
36 | #include <gc/gc_typed.h> |
37 | ||
38 | ||
39 | \f | |
40 | /* Weak pairs for use in weak alist vectors and weak hash tables. | |
41 | ||
42 | We have weal-car pairs, weak-cdr pairs, and doubly weak pairs. In weak | |
43 | pairs, the weak component(s) are not scanned for pointers and are | |
44 | registered as disapperaring links; therefore, the weak component may be | |
45 | set to NULL by the garbage collector when no other reference to that word | |
46 | exist. Thus, users should only access weak pairs via the | |
47 | `SCM_WEAK_PAIR_C[AD]R ()' macros. See also `scm_fixup_weak_alist ()' in | |
48 | `hashtab.c'. */ | |
49 | ||
50 | /* Type descriptors for weak-c[ad]r pairs. */ | |
51 | static GC_descr wcar_pair_descr, wcdr_pair_descr; | |
52 | ||
53 | ||
54 | SCM | |
55 | scm_weak_car_pair (SCM car, SCM cdr) | |
56 | { | |
57 | scm_t_cell *cell; | |
58 | ||
59 | cell = (scm_t_cell *)GC_malloc_explicitly_typed (sizeof (*cell), | |
60 | wcar_pair_descr); | |
61 | ||
62 | cell->word_0 = car; | |
63 | cell->word_1 = cdr; | |
64 | ||
65 | if (SCM_NIMP (car)) | |
d3464bb6 | 66 | /* Weak car cells make sense iff the car is non-immediate. */ |
6922d92f | 67 | SCM_I_REGISTER_DISAPPEARING_LINK ((void **) &cell->word_0, SCM2PTR (car)); |
986ec822 LC |
68 | |
69 | return (SCM_PACK (cell)); | |
70 | } | |
71 | ||
72 | SCM | |
73 | scm_weak_cdr_pair (SCM car, SCM cdr) | |
74 | { | |
75 | scm_t_cell *cell; | |
76 | ||
77 | cell = (scm_t_cell *)GC_malloc_explicitly_typed (sizeof (*cell), | |
78 | wcdr_pair_descr); | |
79 | ||
80 | cell->word_0 = car; | |
81 | cell->word_1 = cdr; | |
82 | ||
83 | if (SCM_NIMP (cdr)) | |
d3464bb6 | 84 | /* Weak cdr cells make sense iff the cdr is non-immediate. */ |
6922d92f | 85 | SCM_I_REGISTER_DISAPPEARING_LINK ((void **) &cell->word_1, SCM2PTR (cdr)); |
986ec822 LC |
86 | |
87 | return (SCM_PACK (cell)); | |
88 | } | |
89 | ||
90 | SCM | |
91 | scm_doubly_weak_pair (SCM car, SCM cdr) | |
92 | { | |
93 | /* Doubly weak cells shall not be scanned at all for pointers. */ | |
94 | scm_t_cell *cell = (scm_t_cell *)scm_gc_malloc_pointerless (sizeof (*cell), | |
95 | "weak cell"); | |
96 | ||
97 | cell->word_0 = car; | |
98 | cell->word_1 = cdr; | |
99 | ||
100 | if (SCM_NIMP (car)) | |
6922d92f | 101 | SCM_I_REGISTER_DISAPPEARING_LINK ((void **) &cell->word_0, SCM2PTR (car)); |
986ec822 | 102 | if (SCM_NIMP (cdr)) |
6922d92f | 103 | SCM_I_REGISTER_DISAPPEARING_LINK ((void **) &cell->word_1, SCM2PTR (cdr)); |
986ec822 LC |
104 | |
105 | return (SCM_PACK (cell)); | |
106 | } | |
107 | ||
108 | ||
592996c9 | 109 | \f |
0f2d19dd | 110 | |
c35738c1 MD |
111 | /* 1. The current hash table implementation in hashtab.c uses weak alist |
112 | * vectors (formerly called weak hash tables) internally. | |
113 | * | |
114 | * 2. All hash table operations still work on alist vectors. | |
115 | * | |
116 | * 3. The weak vector and alist vector Scheme API is accessed through | |
117 | * the module (ice-9 weak-vector). | |
118 | */ | |
119 | ||
120 | ||
0f2d19dd JB |
121 | /* {Weak Vectors} |
122 | */ | |
123 | ||
124 | ||
1e3fd6a0 AW |
125 | #define SCM_VALIDATE_WEAK_VECTOR(pos, var) \ |
126 | SCM_I_MAKE_VALIDATE_MSG2 (pos, var, SCM_I_WVECTP, "weak vector") | |
127 | ||
128 | ||
3b3b36dd | 129 | SCM_DEFINE (scm_make_weak_vector, "make-weak-vector", 1, 1, 0, |
1e6808ea | 130 | (SCM size, SCM fill), |
b380b885 | 131 | "Return a weak vector with @var{size} elements. If the optional\n" |
1e6808ea MG |
132 | "argument @var{fill} is given, all entries in the vector will be\n" |
133 | "set to @var{fill}. The default value for @var{fill} is the\n" | |
134 | "empty list.") | |
1bbd0b84 | 135 | #define FUNC_NAME s_scm_make_weak_vector |
0f2d19dd | 136 | { |
d525e4f9 | 137 | return scm_i_make_weak_vector (0, size, fill); |
0f2d19dd | 138 | } |
1bbd0b84 | 139 | #undef FUNC_NAME |
0f2d19dd JB |
140 | |
141 | ||
1bbd0b84 | 142 | SCM_REGISTER_PROC(s_list_to_weak_vector, "list->weak-vector", 1, 0, 0, scm_weak_vector); |
1cc91f1b | 143 | |
3b3b36dd | 144 | SCM_DEFINE (scm_weak_vector, "weak-vector", 0, 0, 1, |
1bbd0b84 | 145 | (SCM l), |
8f85c0c6 | 146 | "@deffnx {Scheme Procedure} list->weak-vector l\n" |
1e6808ea MG |
147 | "Construct a weak vector from a list: @code{weak-vector} uses\n" |
148 | "the list of its arguments while @code{list->weak-vector} uses\n" | |
149 | "its only argument @var{l} (a list) to construct a weak vector\n" | |
150 | "the same way @code{list->vector} would.") | |
1bbd0b84 | 151 | #define FUNC_NAME s_scm_weak_vector |
0f2d19dd | 152 | { |
d525e4f9 | 153 | return scm_i_make_weak_vector_from_list (0, l); |
0f2d19dd | 154 | } |
1bbd0b84 | 155 | #undef FUNC_NAME |
0f2d19dd JB |
156 | |
157 | ||
3b3b36dd | 158 | SCM_DEFINE (scm_weak_vector_p, "weak-vector?", 1, 0, 0, |
1e6808ea | 159 | (SCM obj), |
5352393c MG |
160 | "Return @code{#t} if @var{obj} is a weak vector. Note that all\n" |
161 | "weak hashes are also weak vectors.") | |
1bbd0b84 | 162 | #define FUNC_NAME s_scm_weak_vector_p |
0f2d19dd | 163 | { |
1e3fd6a0 AW |
164 | return scm_from_bool (scm_is_weak_vector (obj)); |
165 | } | |
166 | #undef FUNC_NAME | |
167 | ||
168 | ||
169 | int | |
170 | scm_is_weak_vector (SCM obj) | |
171 | { | |
172 | return SCM_I_WVECTP (obj) && !SCM_IS_WHVEC (obj); | |
173 | } | |
174 | ||
175 | ||
176 | SCM_DEFINE (scm_weak_vector_length, "weak-vector-length", 1, 0, 0, | |
177 | (SCM wvect), | |
178 | "Returns the number of elements in @var{wvect} as an exact integer.") | |
179 | #define FUNC_NAME s_scm_weak_vector_length | |
180 | { | |
181 | return scm_from_size_t (scm_c_weak_vector_length (wvect)); | |
182 | } | |
183 | #undef FUNC_NAME | |
184 | ||
185 | ||
186 | size_t | |
187 | scm_c_weak_vector_length (SCM wvect) | |
188 | #define FUNC_NAME s_scm_weak_vector_length | |
189 | { | |
190 | SCM_VALIDATE_WEAK_VECTOR (1, wvect); | |
191 | return SCM_I_VECTOR_LENGTH (wvect); | |
192 | } | |
193 | #undef FUNC_NAME | |
194 | ||
195 | ||
196 | SCM_DEFINE (scm_weak_vector_ref, "weak-vector-ref", 2, 0, 0, | |
197 | (SCM wvect, SCM k), | |
198 | "Like @code{vector-ref}, but for weak vectors.") | |
199 | #define FUNC_NAME s_scm_weak_vector_ref | |
200 | { | |
201 | return scm_c_weak_vector_ref (wvect, scm_to_size_t (k)); | |
0f2d19dd | 202 | } |
1bbd0b84 | 203 | #undef FUNC_NAME |
0f2d19dd | 204 | |
1e3fd6a0 AW |
205 | |
206 | SCM | |
207 | scm_c_weak_vector_ref (SCM wvect, size_t k) | |
208 | #define FUNC_NAME s_scm_weak_vector_ref | |
209 | { | |
210 | SCM elt; | |
211 | ||
212 | SCM_VALIDATE_WEAK_VECTOR (1, wvect); | |
213 | ||
214 | if (k >= SCM_I_VECTOR_LENGTH (wvect)) | |
215 | scm_out_of_range (NULL, scm_from_size_t (k)); | |
216 | elt = (SCM_I_VECTOR_ELTS(wvect))[k]; | |
217 | ||
218 | if (SCM_UNPACK (elt) == 0) | |
219 | /* ELT was a weak pointer and got nullified by the GC. */ | |
220 | return SCM_BOOL_F; | |
221 | ||
222 | return elt; | |
223 | } | |
224 | #undef FUNC_NAME | |
225 | ||
226 | ||
227 | SCM_DEFINE (scm_weak_vector_set_x, "weak-vector-set!", 3, 0, 0, | |
228 | (SCM wvect, SCM k, SCM elt), | |
229 | "Like @code{vector-set!}, but for weak vectors.") | |
230 | #define FUNC_NAME s_scm_weak_vector_set_x | |
231 | { | |
232 | scm_c_weak_vector_set_x (wvect, scm_to_size_t (k), elt); | |
233 | ||
234 | return SCM_UNSPECIFIED; | |
235 | } | |
236 | #undef FUNC_NAME | |
237 | ||
238 | ||
239 | void | |
240 | scm_c_weak_vector_set_x (SCM wvect, size_t k, SCM elt) | |
241 | #define FUNC_NAME s_scm_weak_vector_set_x | |
242 | { | |
243 | SCM *loc; | |
244 | ||
245 | SCM_VALIDATE_WEAK_VECTOR (1, wvect); | |
246 | ||
247 | if (k >= SCM_I_VECTOR_LENGTH (wvect)) | |
248 | scm_out_of_range (NULL, scm_from_size_t (k)); | |
249 | ||
250 | loc = & SCM_I_VECTOR_WELTS (wvect)[k]; | |
251 | *loc = elt; | |
252 | ||
253 | /* Make it a weak pointer. */ | |
254 | SCM_I_REGISTER_DISAPPEARING_LINK ((void **) loc, SCM2PTR (elt)); | |
255 | } | |
256 | #undef FUNC_NAME | |
257 | ||
258 | ||
0f2d19dd | 259 | \f |
3a2de079 LC |
260 | /* Weak alist vectors, i.e., vectors of alists. |
261 | ||
262 | The alist vector themselves are _not_ weak. The `car' (or `cdr', or both) | |
263 | of the pairs within it are weak. See `hashtab.c' for details. */ | |
0f2d19dd | 264 | |
4650cdd2 LC |
265 | |
266 | /* FIXME: We used to have two implementations of weak hash tables: the one in | |
267 | here and the one in `hashtab.c'. The difference is that weak alist | |
268 | vectors could be used as vectors while (weak) hash tables can't. We need | |
269 | to unify that. */ | |
270 | ||
c35738c1 | 271 | SCM_DEFINE (scm_make_weak_key_alist_vector, "make-weak-key-alist-vector", 0, 1, 0, |
1e6808ea | 272 | (SCM size), |
c35738c1 MD |
273 | "@deffnx {Scheme Procedure} make-weak-value-alist-vector size\n" |
274 | "@deffnx {Scheme Procedure} make-doubly-weak-alist-vector size\n" | |
1e6808ea MG |
275 | "Return a weak hash table with @var{size} buckets. As with any\n" |
276 | "hash table, choosing a good size for the table requires some\n" | |
277 | "caution.\n" | |
278 | "\n" | |
279 | "You can modify weak hash tables in exactly the same way you\n" | |
280 | "would modify regular hash tables. (@pxref{Hash Tables})") | |
c35738c1 | 281 | #define FUNC_NAME s_scm_make_weak_key_alist_vector |
0f2d19dd | 282 | { |
4650cdd2 | 283 | return scm_make_weak_key_hash_table (size); |
0f2d19dd | 284 | } |
1bbd0b84 | 285 | #undef FUNC_NAME |
0f2d19dd JB |
286 | |
287 | ||
c35738c1 | 288 | SCM_DEFINE (scm_make_weak_value_alist_vector, "make-weak-value-alist-vector", 0, 1, 0, |
1e6808ea | 289 | (SCM size), |
e3239868 DH |
290 | "Return a hash table with weak values with @var{size} buckets.\n" |
291 | "(@pxref{Hash Tables})") | |
c35738c1 | 292 | #define FUNC_NAME s_scm_make_weak_value_alist_vector |
0f2d19dd | 293 | { |
4650cdd2 | 294 | return scm_make_weak_value_hash_table (size); |
0f2d19dd | 295 | } |
1bbd0b84 | 296 | #undef FUNC_NAME |
0f2d19dd JB |
297 | |
298 | ||
c35738c1 | 299 | SCM_DEFINE (scm_make_doubly_weak_alist_vector, "make-doubly-weak-alist-vector", 1, 0, 0, |
1e6808ea | 300 | (SCM size), |
e3239868 DH |
301 | "Return a hash table with weak keys and values with @var{size}\n" |
302 | "buckets. (@pxref{Hash Tables})") | |
c35738c1 | 303 | #define FUNC_NAME s_scm_make_doubly_weak_alist_vector |
0f2d19dd | 304 | { |
b6ed39c4 | 305 | return scm_make_doubly_weak_hash_table (size); |
0f2d19dd | 306 | } |
1bbd0b84 | 307 | #undef FUNC_NAME |
0f2d19dd | 308 | |
592996c9 | 309 | |
c35738c1 | 310 | SCM_DEFINE (scm_weak_key_alist_vector_p, "weak-key-alist-vector?", 1, 0, 0, |
1e6808ea | 311 | (SCM obj), |
c35738c1 MD |
312 | "@deffnx {Scheme Procedure} weak-value-alist-vector? obj\n" |
313 | "@deffnx {Scheme Procedure} doubly-weak-alist-vector? obj\n" | |
5352393c MG |
314 | "Return @code{#t} if @var{obj} is the specified weak hash\n" |
315 | "table. Note that a doubly weak hash table is neither a weak key\n" | |
316 | "nor a weak value hash table.") | |
c35738c1 | 317 | #define FUNC_NAME s_scm_weak_key_alist_vector_p |
0f2d19dd | 318 | { |
6e708ef2 | 319 | return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC (obj)); |
0f2d19dd | 320 | } |
1bbd0b84 | 321 | #undef FUNC_NAME |
0f2d19dd JB |
322 | |
323 | ||
c35738c1 | 324 | SCM_DEFINE (scm_weak_value_alist_vector_p, "weak-value-alist-vector?", 1, 0, 0, |
1e6808ea MG |
325 | (SCM obj), |
326 | "Return @code{#t} if @var{obj} is a weak value hash table.") | |
c35738c1 | 327 | #define FUNC_NAME s_scm_weak_value_alist_vector_p |
0f2d19dd | 328 | { |
6e708ef2 | 329 | return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC_V (obj)); |
0f2d19dd | 330 | } |
1bbd0b84 | 331 | #undef FUNC_NAME |
0f2d19dd JB |
332 | |
333 | ||
c35738c1 | 334 | SCM_DEFINE (scm_doubly_weak_alist_vector_p, "doubly-weak-alist-vector?", 1, 0, 0, |
1e6808ea MG |
335 | (SCM obj), |
336 | "Return @code{#t} if @var{obj} is a doubly weak hash table.") | |
c35738c1 | 337 | #define FUNC_NAME s_scm_doubly_weak_alist_vector_p |
0f2d19dd | 338 | { |
6e708ef2 | 339 | return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC_B (obj)); |
0f2d19dd | 340 | } |
1bbd0b84 | 341 | #undef FUNC_NAME |
0f2d19dd | 342 | |
592996c9 | 343 | |
592996c9 | 344 | |
06c1d900 | 345 | \f |
c35738c1 MD |
346 | SCM |
347 | scm_init_weaks_builtins () | |
348 | { | |
349 | #include "libguile/weaks.x" | |
350 | return SCM_UNSPECIFIED; | |
351 | } | |
352 | ||
986ec822 LC |
353 | void |
354 | scm_weaks_prehistory () | |
355 | { | |
356 | /* Initialize weak pairs. */ | |
357 | GC_word wcar_pair_bitmap[GC_BITMAP_SIZE (scm_t_cell)] = { 0 }; | |
358 | GC_word wcdr_pair_bitmap[GC_BITMAP_SIZE (scm_t_cell)] = { 0 }; | |
359 | ||
360 | /* In a weak-car pair, only the second word must be scanned for | |
361 | pointers. */ | |
362 | GC_set_bit (wcar_pair_bitmap, GC_WORD_OFFSET (scm_t_cell, word_1)); | |
363 | wcar_pair_descr = GC_make_descriptor (wcar_pair_bitmap, | |
364 | GC_WORD_LEN (scm_t_cell)); | |
365 | ||
366 | /* Conversely, in a weak-cdr pair, only the first word must be scanned for | |
367 | pointers. */ | |
368 | GC_set_bit (wcdr_pair_bitmap, GC_WORD_OFFSET (scm_t_cell, word_0)); | |
369 | wcdr_pair_descr = GC_make_descriptor (wcdr_pair_bitmap, | |
370 | GC_WORD_LEN (scm_t_cell)); | |
371 | ||
372 | } | |
373 | ||
0f2d19dd JB |
374 | void |
375 | scm_init_weaks () | |
0f2d19dd | 376 | { |
c35738c1 MD |
377 | scm_c_define_gsubr ("%init-weaks-builtins", 0, 0, 0, |
378 | scm_init_weaks_builtins); | |
0f2d19dd JB |
379 | } |
380 | ||
89e00824 ML |
381 | |
382 | /* | |
383 | Local Variables: | |
384 | c-file-style: "gnu" | |
385 | End: | |
386 | */ |