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6922d92f LC |
1 | /* Copyright (C) 1995, 1996, 1998, 2000, 2001, 2003, 2006, 2008, 2009, 2010, |
2 | * 2011, 2012 Free Software Foundation, Inc. | |
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 | * |
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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 | |
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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 | ||
3b3b36dd | 125 | SCM_DEFINE (scm_make_weak_vector, "make-weak-vector", 1, 1, 0, |
1e6808ea | 126 | (SCM size, SCM fill), |
b380b885 | 127 | "Return a weak vector with @var{size} elements. If the optional\n" |
1e6808ea MG |
128 | "argument @var{fill} is given, all entries in the vector will be\n" |
129 | "set to @var{fill}. The default value for @var{fill} is the\n" | |
130 | "empty list.") | |
1bbd0b84 | 131 | #define FUNC_NAME s_scm_make_weak_vector |
0f2d19dd | 132 | { |
d525e4f9 | 133 | return scm_i_make_weak_vector (0, size, fill); |
0f2d19dd | 134 | } |
1bbd0b84 | 135 | #undef FUNC_NAME |
0f2d19dd JB |
136 | |
137 | ||
1bbd0b84 | 138 | SCM_REGISTER_PROC(s_list_to_weak_vector, "list->weak-vector", 1, 0, 0, scm_weak_vector); |
1cc91f1b | 139 | |
3b3b36dd | 140 | SCM_DEFINE (scm_weak_vector, "weak-vector", 0, 0, 1, |
1bbd0b84 | 141 | (SCM l), |
8f85c0c6 | 142 | "@deffnx {Scheme Procedure} list->weak-vector l\n" |
1e6808ea MG |
143 | "Construct a weak vector from a list: @code{weak-vector} uses\n" |
144 | "the list of its arguments while @code{list->weak-vector} uses\n" | |
145 | "its only argument @var{l} (a list) to construct a weak vector\n" | |
146 | "the same way @code{list->vector} would.") | |
1bbd0b84 | 147 | #define FUNC_NAME s_scm_weak_vector |
0f2d19dd | 148 | { |
d525e4f9 | 149 | return scm_i_make_weak_vector_from_list (0, l); |
0f2d19dd | 150 | } |
1bbd0b84 | 151 | #undef FUNC_NAME |
0f2d19dd JB |
152 | |
153 | ||
3b3b36dd | 154 | SCM_DEFINE (scm_weak_vector_p, "weak-vector?", 1, 0, 0, |
1e6808ea | 155 | (SCM obj), |
5352393c MG |
156 | "Return @code{#t} if @var{obj} is a weak vector. Note that all\n" |
157 | "weak hashes are also weak vectors.") | |
1bbd0b84 | 158 | #define FUNC_NAME s_scm_weak_vector_p |
0f2d19dd | 159 | { |
6e708ef2 | 160 | return scm_from_bool (SCM_I_WVECTP (obj) && !SCM_IS_WHVEC (obj)); |
0f2d19dd | 161 | } |
1bbd0b84 | 162 | #undef FUNC_NAME |
0f2d19dd | 163 | |
0f2d19dd | 164 | \f |
3a2de079 LC |
165 | /* Weak alist vectors, i.e., vectors of alists. |
166 | ||
167 | The alist vector themselves are _not_ weak. The `car' (or `cdr', or both) | |
168 | of the pairs within it are weak. See `hashtab.c' for details. */ | |
0f2d19dd | 169 | |
4650cdd2 LC |
170 | |
171 | /* FIXME: We used to have two implementations of weak hash tables: the one in | |
172 | here and the one in `hashtab.c'. The difference is that weak alist | |
173 | vectors could be used as vectors while (weak) hash tables can't. We need | |
174 | to unify that. */ | |
175 | ||
c35738c1 | 176 | SCM_DEFINE (scm_make_weak_key_alist_vector, "make-weak-key-alist-vector", 0, 1, 0, |
1e6808ea | 177 | (SCM size), |
c35738c1 MD |
178 | "@deffnx {Scheme Procedure} make-weak-value-alist-vector size\n" |
179 | "@deffnx {Scheme Procedure} make-doubly-weak-alist-vector size\n" | |
1e6808ea MG |
180 | "Return a weak hash table with @var{size} buckets. As with any\n" |
181 | "hash table, choosing a good size for the table requires some\n" | |
182 | "caution.\n" | |
183 | "\n" | |
184 | "You can modify weak hash tables in exactly the same way you\n" | |
185 | "would modify regular hash tables. (@pxref{Hash Tables})") | |
c35738c1 | 186 | #define FUNC_NAME s_scm_make_weak_key_alist_vector |
0f2d19dd | 187 | { |
4650cdd2 | 188 | return scm_make_weak_key_hash_table (size); |
0f2d19dd | 189 | } |
1bbd0b84 | 190 | #undef FUNC_NAME |
0f2d19dd JB |
191 | |
192 | ||
c35738c1 | 193 | SCM_DEFINE (scm_make_weak_value_alist_vector, "make-weak-value-alist-vector", 0, 1, 0, |
1e6808ea | 194 | (SCM size), |
e3239868 DH |
195 | "Return a hash table with weak values with @var{size} buckets.\n" |
196 | "(@pxref{Hash Tables})") | |
c35738c1 | 197 | #define FUNC_NAME s_scm_make_weak_value_alist_vector |
0f2d19dd | 198 | { |
4650cdd2 | 199 | return scm_make_weak_value_hash_table (size); |
0f2d19dd | 200 | } |
1bbd0b84 | 201 | #undef FUNC_NAME |
0f2d19dd JB |
202 | |
203 | ||
c35738c1 | 204 | SCM_DEFINE (scm_make_doubly_weak_alist_vector, "make-doubly-weak-alist-vector", 1, 0, 0, |
1e6808ea | 205 | (SCM size), |
e3239868 DH |
206 | "Return a hash table with weak keys and values with @var{size}\n" |
207 | "buckets. (@pxref{Hash Tables})") | |
c35738c1 | 208 | #define FUNC_NAME s_scm_make_doubly_weak_alist_vector |
0f2d19dd | 209 | { |
b6ed39c4 | 210 | return scm_make_doubly_weak_hash_table (size); |
0f2d19dd | 211 | } |
1bbd0b84 | 212 | #undef FUNC_NAME |
0f2d19dd | 213 | |
592996c9 | 214 | |
c35738c1 | 215 | SCM_DEFINE (scm_weak_key_alist_vector_p, "weak-key-alist-vector?", 1, 0, 0, |
1e6808ea | 216 | (SCM obj), |
c35738c1 MD |
217 | "@deffnx {Scheme Procedure} weak-value-alist-vector? obj\n" |
218 | "@deffnx {Scheme Procedure} doubly-weak-alist-vector? obj\n" | |
5352393c MG |
219 | "Return @code{#t} if @var{obj} is the specified weak hash\n" |
220 | "table. Note that a doubly weak hash table is neither a weak key\n" | |
221 | "nor a weak value hash table.") | |
c35738c1 | 222 | #define FUNC_NAME s_scm_weak_key_alist_vector_p |
0f2d19dd | 223 | { |
6e708ef2 | 224 | return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC (obj)); |
0f2d19dd | 225 | } |
1bbd0b84 | 226 | #undef FUNC_NAME |
0f2d19dd JB |
227 | |
228 | ||
c35738c1 | 229 | SCM_DEFINE (scm_weak_value_alist_vector_p, "weak-value-alist-vector?", 1, 0, 0, |
1e6808ea MG |
230 | (SCM obj), |
231 | "Return @code{#t} if @var{obj} is a weak value hash table.") | |
c35738c1 | 232 | #define FUNC_NAME s_scm_weak_value_alist_vector_p |
0f2d19dd | 233 | { |
6e708ef2 | 234 | return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC_V (obj)); |
0f2d19dd | 235 | } |
1bbd0b84 | 236 | #undef FUNC_NAME |
0f2d19dd JB |
237 | |
238 | ||
c35738c1 | 239 | SCM_DEFINE (scm_doubly_weak_alist_vector_p, "doubly-weak-alist-vector?", 1, 0, 0, |
1e6808ea MG |
240 | (SCM obj), |
241 | "Return @code{#t} if @var{obj} is a doubly weak hash table.") | |
c35738c1 | 242 | #define FUNC_NAME s_scm_doubly_weak_alist_vector_p |
0f2d19dd | 243 | { |
6e708ef2 | 244 | return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC_B (obj)); |
0f2d19dd | 245 | } |
1bbd0b84 | 246 | #undef FUNC_NAME |
0f2d19dd | 247 | |
592996c9 | 248 | |
592996c9 | 249 | |
06c1d900 | 250 | \f |
c35738c1 MD |
251 | SCM |
252 | scm_init_weaks_builtins () | |
253 | { | |
254 | #include "libguile/weaks.x" | |
255 | return SCM_UNSPECIFIED; | |
256 | } | |
257 | ||
986ec822 LC |
258 | void |
259 | scm_weaks_prehistory () | |
260 | { | |
261 | /* Initialize weak pairs. */ | |
262 | GC_word wcar_pair_bitmap[GC_BITMAP_SIZE (scm_t_cell)] = { 0 }; | |
263 | GC_word wcdr_pair_bitmap[GC_BITMAP_SIZE (scm_t_cell)] = { 0 }; | |
264 | ||
265 | /* In a weak-car pair, only the second word must be scanned for | |
266 | pointers. */ | |
267 | GC_set_bit (wcar_pair_bitmap, GC_WORD_OFFSET (scm_t_cell, word_1)); | |
268 | wcar_pair_descr = GC_make_descriptor (wcar_pair_bitmap, | |
269 | GC_WORD_LEN (scm_t_cell)); | |
270 | ||
271 | /* Conversely, in a weak-cdr pair, only the first word must be scanned for | |
272 | pointers. */ | |
273 | GC_set_bit (wcdr_pair_bitmap, GC_WORD_OFFSET (scm_t_cell, word_0)); | |
274 | wcdr_pair_descr = GC_make_descriptor (wcdr_pair_bitmap, | |
275 | GC_WORD_LEN (scm_t_cell)); | |
276 | ||
277 | } | |
278 | ||
0f2d19dd JB |
279 | void |
280 | scm_init_weaks () | |
0f2d19dd | 281 | { |
c35738c1 MD |
282 | scm_c_define_gsubr ("%init-weaks-builtins", 0, 0, 0, |
283 | scm_init_weaks_builtins); | |
0f2d19dd JB |
284 | } |
285 | ||
89e00824 ML |
286 | |
287 | /* | |
288 | Local Variables: | |
289 | c-file-style: "gnu" | |
290 | End: | |
291 | */ |