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1 | /* -*-c-*- |
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2 | * |
3 | * Allocation and freeing of MP buffers |
4 | * |
5 | * (c) 1999 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
45c0fd36 |
16 | * |
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17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include <stdio.h> |
31 | #include <stdlib.h> |
32 | #include <string.h> |
33 | |
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34 | #include <mLib/arena.h> |
35 | #include <mLib/exc.h> |
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36 | #include <mLib/sub.h> |
37 | |
38 | #include "mparena.h" |
39 | |
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40 | /*----- Tweakables --------------------------------------------------------*/ |
41 | |
48d66950 |
42 | /* --- @MPARENA_TRIVIAL@ --- * |
43 | * |
44 | * Make the allocator a passthrough. It immediately calls the underlying |
45 | * allocation functions rather than attempting to keep track of blocks |
46 | * itself. |
47 | */ |
48 | |
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49 | #define MPARENA_TRIVIAL |
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50 | |
48d66950 |
51 | /* --- @MPARENA_DEBUG@ --- * |
52 | * |
53 | * The name of an output trace file to which logging information about the |
54 | * state of arena trees should be written. If unset, no logging is done. |
55 | */ |
56 | |
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57 | /* #define MPARENA_DEBUG "mparena.out" */ |
58 | |
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59 | /*----- Static variables --------------------------------------------------*/ |
60 | |
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61 | #ifdef MPARENA_DEBUG |
62 | static FILE *debugfp = 0; |
63 | |
64 | # define MPARENA_OPENFILE do { \ |
65 | if (!debugfp) { \ |
66 | if ((debugfp = fopen(MPARENA_DEBUG, "w")) == 0) { \ |
67 | fprintf(stderr, "couldn't open debug output file\n"); \ |
68 | exit(EXIT_FAILURE); \ |
69 | } \ |
70 | } \ |
71 | } while (0) |
72 | |
73 | #endif |
74 | |
d4745354 |
75 | /*----- Standard arenas ---------------------------------------------------*/ |
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76 | |
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77 | mparena mparena_global = MPARENA_INIT; |
78 | mparena mparena_secure = MPARENA_INIT; |
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79 | |
80 | /*----- Main code ---------------------------------------------------------*/ |
81 | |
82 | /* --- @tdump@ --- * |
83 | * |
84 | * Arguments: @mparena_node *n@ = pointer to tree node to dump |
85 | * |
86 | * Returns: --- |
87 | * |
88 | * Use: Recursively dumps out the allocation tree. |
89 | */ |
90 | |
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91 | #ifdef MPARENA_DEBUG |
92 | |
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93 | static void tdump(mparena_node *n) |
94 | { |
95 | if (!n) |
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96 | putc('*', debugfp); |
d3409d5e |
97 | else { |
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98 | putc('(', debugfp); |
d3409d5e |
99 | tdump(n->left); |
12a9a6e5 |
100 | fprintf(debugfp, ", %u, ", n->v[0]); |
d3409d5e |
101 | tdump(n->right); |
12a9a6e5 |
102 | putc(')', debugfp); |
d3409d5e |
103 | } |
104 | } |
105 | |
12a9a6e5 |
106 | #endif |
107 | |
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108 | /* --- @mparena_create@ --- * |
109 | * |
110 | * Arguments: @mparena *a@ = pointer to arena block |
111 | * |
112 | * Returns: --- |
113 | * |
114 | * Use: Initializes an MP arena so that blocks can be allocated from |
115 | * it. |
116 | */ |
117 | |
118 | void mparena_create(mparena *a) |
119 | { |
120 | a->root = 0; |
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121 | a->n = 0; |
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122 | a->a = &arena_stdlib; |
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123 | } |
124 | |
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125 | /* --- @mparena_setarena@ --- * |
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126 | * |
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127 | * Arguments: @mparena *a@ = pointer to MP arena block |
128 | * @arena *aa@ = pointer to arena |
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129 | * |
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130 | * Returns: --- |
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131 | * |
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132 | * Use: Sets the underlying arena for an MP arena. |
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133 | */ |
134 | |
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135 | extern void mparena_setarena(mparena *a, arena *aa) { a->a = aa; } |
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136 | |
137 | /* --- @mparena_destroy@ --- * |
138 | * |
139 | * Arguments: @mparena *a@ = pointer to arena block |
140 | * |
141 | * Returns: --- |
142 | * |
143 | * Use: Frees an MP arena, and all the vectors held within it. The |
144 | * blocks which are currently allocated can be freed into some |
145 | * other arena. |
146 | */ |
147 | |
148 | static void tfree(mparena *a, mparena_node *n) |
149 | { |
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150 | A_FREE(a->a, n->v); |
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151 | if (n->left) |
152 | tfree(a, n->left); |
153 | if (n->right) |
154 | tfree(a, n->right); |
155 | DESTROY(n); |
156 | } |
157 | |
158 | void mparena_destroy(mparena *a) |
159 | { |
160 | tfree(a, a->root); |
161 | a->root = 0; |
162 | } |
163 | |
97d21728 |
164 | /* --- @mparena_count@ --- * |
165 | * |
166 | * Arguments: @mparena *a@ = pointer to arena block |
167 | * |
168 | * Returns: Number of allocated blocks from this arena. |
169 | * |
170 | * Use: Reports the number of blocks allocated from the arena and not |
171 | * yet freed. |
172 | */ |
173 | |
174 | unsigned mparena_count(mparena *a) |
175 | { |
97d21728 |
176 | return (a->n); |
45c0fd36 |
177 | } |
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178 | |
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179 | /* --- @mpalloc@ --- * |
180 | * |
181 | * Arguments: @mparena *a@ = pointer to arena block |
182 | * @size_t sz@ = number of digits required |
183 | * |
184 | * Returns: Pointer to a suitably sized block. |
185 | * |
186 | * Use: Allocates a lump of data suitable for use as an array of MP |
187 | * digits. |
188 | */ |
189 | |
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190 | #ifdef MPARENA_TRIVIAL |
191 | |
192 | mpw *mpalloc(mparena *a, size_t sz) |
193 | { |
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194 | mpw *v; |
02d7884d |
195 | if (!sz) return (0); |
196 | a->n++; |
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197 | v = A_ALLOC(a->a, MPWS(sz)); |
198 | if (!v) |
199 | THROW(EXC_NOMEM); |
200 | return (v); |
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201 | } |
202 | |
203 | #else |
204 | |
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205 | mpw *mpalloc(mparena *a, size_t sz) |
206 | { |
207 | mparena_node **nn, *n; |
208 | mpw *v; |
209 | |
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210 | nn = &a->root; |
211 | |
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212 | #ifdef MPARENA_DEBUG |
213 | MPARENA_OPENFILE; |
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214 | fprintf(debugfp, "alloc %u\n before: ", sz); |
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215 | tdump(a->root); putc('\n', debugfp); |
d3409d5e |
216 | #endif |
217 | |
218 | /* --- First, find a block which is big enough --- */ |
219 | |
220 | again: |
221 | n = *nn; |
222 | if (!n) { |
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223 | #ifdef MPARENA_DEBUG |
224 | fputs(" failed\n", debugfp); |
225 | #endif |
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226 | if ((v = A_ALLOC(a->a, MPWS(sz + 1))) == 0) |
227 | THROW(EXC_NOMEM); |
d3409d5e |
228 | v[0] = sz; |
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229 | a->n++; |
d3409d5e |
230 | return (v + 1); |
231 | } |
232 | if (n->v[0] < sz) { |
233 | nn = &n->right; |
234 | goto again; |
235 | } |
236 | |
237 | /* --- Now try to find a smaller block which is suitable --- */ |
238 | |
239 | while (n->left && n->left->v[0] >= sz) { |
240 | nn = &n->left; |
241 | n = *nn; |
242 | } |
243 | |
244 | /* --- If the block we've got is still too large, start digging --- */ |
245 | |
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246 | if (n->v[0] > sz * 2) { |
d3409d5e |
247 | nn = &n->left; |
248 | goto again; |
249 | } |
250 | |
251 | /* --- I've now found a suitable block --- */ |
252 | |
253 | v = n->v; |
254 | |
255 | /* --- Remove this node from the tree --- */ |
256 | |
257 | if (!n->left) |
258 | *nn = n->right; |
259 | else if (!n->right) |
260 | *nn = n->left; |
261 | else { |
262 | mparena_node *left = n->left; |
263 | mparena_node *p = *nn = n->right; |
264 | while (p->left) |
265 | p = p->left; |
266 | p->left = left; |
267 | } |
268 | |
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269 | #ifdef MPARENA_DEBUG |
270 | fputs(" after: ", debugfp); |
271 | tdump(a->root); putc('\n', debugfp); |
272 | #endif |
273 | |
d3409d5e |
274 | /* --- Get rid of this node now --- */ |
275 | |
276 | DESTROY(n); |
97d21728 |
277 | a->n++; |
d3409d5e |
278 | return (v + 1); |
279 | } |
280 | |
12a9a6e5 |
281 | #endif |
282 | |
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283 | /* --- @mpfree@ --- * |
284 | * |
285 | * Arguments: @mparena *a@ = pointer to arena block |
286 | * @mpw *v@ = pointer to allocated vector |
287 | * |
288 | * Returns: --- |
289 | * |
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290 | * Use: Returns an MP vector to an arena. |
d3409d5e |
291 | */ |
292 | |
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293 | #ifdef MPARENA_TRIVIAL |
294 | |
295 | void mpfree(mparena *a, mpw *v) |
296 | { |
02d7884d |
297 | if (!v) return; |
298 | a->n--; |
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299 | A_FREE(a->a, v); |
12a9a6e5 |
300 | } |
301 | |
302 | #else |
303 | |
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304 | void mpfree(mparena *a, mpw *v) |
305 | { |
306 | mparena_node **nn, *n; |
307 | size_t sz = *--v; |
308 | |
12a9a6e5 |
309 | #ifdef MPARENA_DEBUG |
310 | MPARENA_OPENFILE; |
311 | fprintf(debugfp, "free %u\n before: ", sz); |
312 | tdump(a->root); putc('\n', debugfp); |
313 | #endif |
314 | |
315 | nn = &a->root; |
d3409d5e |
316 | while (*nn) { |
317 | n = *nn; |
318 | if (n->v[0] > sz) |
319 | nn = &n->left; |
320 | else |
321 | nn = &n->right; |
322 | } |
323 | |
324 | n = CREATE(mparena_node); |
325 | n->left = n->right = 0; |
326 | n->v = v; |
327 | *nn = n; |
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328 | a->n--; |
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329 | |
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330 | #ifdef MPARENA_DEBUG |
331 | fputs(" after: ", debugfp); |
332 | tdump(a->root); putc('\n', debugfp); |
d3409d5e |
333 | #endif |
334 | } |
335 | |
12a9a6e5 |
336 | #endif |
337 | |
d3409d5e |
338 | /*----- That's all, folks -------------------------------------------------*/ |