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1 | /* -*-c-*- |
2 | * |
02d7884d |
3 | * $Id: mparena.c,v 1.6 2004/04/03 03:32:05 mdw Exp $ |
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4 | * |
5 | * Allocation and freeing of MP buffers |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: mparena.c,v $ |
02d7884d |
33 | * Revision 1.6 2004/04/03 03:32:05 mdw |
34 | * General robustification. |
35 | * |
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36 | * Revision 1.5 2000/06/17 11:35:48 mdw |
37 | * Overhaul to use mLib's arena system underneath. |
38 | * |
97d21728 |
39 | * Revision 1.4 1999/12/10 23:28:52 mdw |
40 | * Memory allocation counting. |
41 | * |
48d66950 |
42 | * Revision 1.3 1999/11/22 13:58:00 mdw |
43 | * Document the tweakables. |
44 | * |
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45 | * Revision 1.2 1999/11/21 22:14:19 mdw |
46 | * Fix bug. Improve diagnostic capabilities. |
47 | * |
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48 | * Revision 1.1 1999/11/17 18:02:16 mdw |
49 | * New multiprecision integer arithmetic suite. |
50 | * |
51 | */ |
52 | |
53 | /*----- Header files ------------------------------------------------------*/ |
54 | |
55 | #include <stdio.h> |
56 | #include <stdlib.h> |
57 | #include <string.h> |
58 | |
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59 | #include <mLib/arena.h> |
60 | #include <mLib/exc.h> |
d3409d5e |
61 | #include <mLib/sub.h> |
62 | |
63 | #include "mparena.h" |
64 | |
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65 | /*----- Tweakables --------------------------------------------------------*/ |
66 | |
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67 | /* --- @MPARENA_TRIVIAL@ --- * |
68 | * |
69 | * Make the allocator a passthrough. It immediately calls the underlying |
70 | * allocation functions rather than attempting to keep track of blocks |
71 | * itself. |
72 | */ |
73 | |
12a9a6e5 |
74 | /* #define MPARENA_TRIVIAL */ |
75 | |
48d66950 |
76 | /* --- @MPARENA_DEBUG@ --- * |
77 | * |
78 | * The name of an output trace file to which logging information about the |
79 | * state of arena trees should be written. If unset, no logging is done. |
80 | */ |
81 | |
12a9a6e5 |
82 | /* #define MPARENA_DEBUG "mparena.out" */ |
83 | |
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84 | /*----- Static variables --------------------------------------------------*/ |
85 | |
12a9a6e5 |
86 | #ifdef MPARENA_DEBUG |
87 | static FILE *debugfp = 0; |
88 | |
89 | # define MPARENA_OPENFILE do { \ |
90 | if (!debugfp) { \ |
91 | if ((debugfp = fopen(MPARENA_DEBUG, "w")) == 0) { \ |
92 | fprintf(stderr, "couldn't open debug output file\n"); \ |
93 | exit(EXIT_FAILURE); \ |
94 | } \ |
95 | } \ |
96 | } while (0) |
97 | |
98 | #endif |
99 | |
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100 | /*----- Standard arenas ---------------------------------------------------*/ |
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101 | |
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102 | mparena mparena_global = MPARENA_INIT; |
103 | mparena mparena_secure = MPARENA_INIT; |
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104 | |
105 | /*----- Main code ---------------------------------------------------------*/ |
106 | |
107 | /* --- @tdump@ --- * |
108 | * |
109 | * Arguments: @mparena_node *n@ = pointer to tree node to dump |
110 | * |
111 | * Returns: --- |
112 | * |
113 | * Use: Recursively dumps out the allocation tree. |
114 | */ |
115 | |
12a9a6e5 |
116 | #ifdef MPARENA_DEBUG |
117 | |
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118 | static void tdump(mparena_node *n) |
119 | { |
120 | if (!n) |
12a9a6e5 |
121 | putc('*', debugfp); |
d3409d5e |
122 | else { |
12a9a6e5 |
123 | putc('(', debugfp); |
d3409d5e |
124 | tdump(n->left); |
12a9a6e5 |
125 | fprintf(debugfp, ", %u, ", n->v[0]); |
d3409d5e |
126 | tdump(n->right); |
12a9a6e5 |
127 | putc(')', debugfp); |
d3409d5e |
128 | } |
129 | } |
130 | |
12a9a6e5 |
131 | #endif |
132 | |
d3409d5e |
133 | /* --- @mparena_create@ --- * |
134 | * |
135 | * Arguments: @mparena *a@ = pointer to arena block |
136 | * |
137 | * Returns: --- |
138 | * |
139 | * Use: Initializes an MP arena so that blocks can be allocated from |
140 | * it. |
141 | */ |
142 | |
143 | void mparena_create(mparena *a) |
144 | { |
145 | a->root = 0; |
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146 | a->n = 0; |
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147 | a->a = &arena_stdlib; |
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148 | } |
149 | |
d4745354 |
150 | /* --- @mparena_setarena@ --- * |
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151 | * |
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152 | * Arguments: @mparena *a@ = pointer to MP arena block |
153 | * @arena *aa@ = pointer to arena |
d3409d5e |
154 | * |
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155 | * Returns: --- |
d3409d5e |
156 | * |
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157 | * Use: Sets the underlying arena for an MP arena. |
d3409d5e |
158 | */ |
159 | |
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160 | extern void mparena_setarena(mparena *a, arena *aa) { a->a = aa; } |
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161 | |
162 | /* --- @mparena_destroy@ --- * |
163 | * |
164 | * Arguments: @mparena *a@ = pointer to arena block |
165 | * |
166 | * Returns: --- |
167 | * |
168 | * Use: Frees an MP arena, and all the vectors held within it. The |
169 | * blocks which are currently allocated can be freed into some |
170 | * other arena. |
171 | */ |
172 | |
173 | static void tfree(mparena *a, mparena_node *n) |
174 | { |
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175 | A_FREE(a->a, n->v); |
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176 | if (n->left) |
177 | tfree(a, n->left); |
178 | if (n->right) |
179 | tfree(a, n->right); |
180 | DESTROY(n); |
181 | } |
182 | |
183 | void mparena_destroy(mparena *a) |
184 | { |
185 | tfree(a, a->root); |
186 | a->root = 0; |
187 | } |
188 | |
97d21728 |
189 | /* --- @mparena_count@ --- * |
190 | * |
191 | * Arguments: @mparena *a@ = pointer to arena block |
192 | * |
193 | * Returns: Number of allocated blocks from this arena. |
194 | * |
195 | * Use: Reports the number of blocks allocated from the arena and not |
196 | * yet freed. |
197 | */ |
198 | |
199 | unsigned mparena_count(mparena *a) |
200 | { |
97d21728 |
201 | return (a->n); |
202 | } |
203 | |
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204 | /* --- @mpalloc@ --- * |
205 | * |
206 | * Arguments: @mparena *a@ = pointer to arena block |
207 | * @size_t sz@ = number of digits required |
208 | * |
209 | * Returns: Pointer to a suitably sized block. |
210 | * |
211 | * Use: Allocates a lump of data suitable for use as an array of MP |
212 | * digits. |
213 | */ |
214 | |
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215 | #ifdef MPARENA_TRIVIAL |
216 | |
217 | mpw *mpalloc(mparena *a, size_t sz) |
218 | { |
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219 | mpw *v; |
02d7884d |
220 | if (!sz) return (0); |
221 | a->n++; |
d4745354 |
222 | v = A_ALLOC(a->a, MPWS(sz)); |
223 | if (!v) |
224 | THROW(EXC_NOMEM); |
225 | return (v); |
12a9a6e5 |
226 | } |
227 | |
228 | #else |
229 | |
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230 | mpw *mpalloc(mparena *a, size_t sz) |
231 | { |
232 | mparena_node **nn, *n; |
233 | mpw *v; |
234 | |
d3409d5e |
235 | nn = &a->root; |
236 | |
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237 | #ifdef MPARENA_DEBUG |
238 | MPARENA_OPENFILE; |
239 | fprintf(debugfp, "alloc %u\n before: ", sz); |
240 | tdump(a->root); putc('\n', debugfp); |
d3409d5e |
241 | #endif |
242 | |
243 | /* --- First, find a block which is big enough --- */ |
244 | |
245 | again: |
246 | n = *nn; |
247 | if (!n) { |
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248 | #ifdef MPARENA_DEBUG |
249 | fputs(" failed\n", debugfp); |
250 | #endif |
d4745354 |
251 | if ((v = A_ALLOC(a->a, MPWS(sz + 1))) == 0) |
252 | THROW(EXC_NOMEM); |
d3409d5e |
253 | v[0] = sz; |
97d21728 |
254 | a->n++; |
d3409d5e |
255 | return (v + 1); |
256 | } |
257 | if (n->v[0] < sz) { |
258 | nn = &n->right; |
259 | goto again; |
260 | } |
261 | |
262 | /* --- Now try to find a smaller block which is suitable --- */ |
263 | |
264 | while (n->left && n->left->v[0] >= sz) { |
265 | nn = &n->left; |
266 | n = *nn; |
267 | } |
268 | |
269 | /* --- If the block we've got is still too large, start digging --- */ |
270 | |
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271 | if (n->v[0] > sz * 2) { |
d3409d5e |
272 | nn = &n->left; |
273 | goto again; |
274 | } |
275 | |
276 | /* --- I've now found a suitable block --- */ |
277 | |
278 | v = n->v; |
279 | |
280 | /* --- Remove this node from the tree --- */ |
281 | |
282 | if (!n->left) |
283 | *nn = n->right; |
284 | else if (!n->right) |
285 | *nn = n->left; |
286 | else { |
287 | mparena_node *left = n->left; |
288 | mparena_node *p = *nn = n->right; |
289 | while (p->left) |
290 | p = p->left; |
291 | p->left = left; |
292 | } |
293 | |
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294 | #ifdef MPARENA_DEBUG |
295 | fputs(" after: ", debugfp); |
296 | tdump(a->root); putc('\n', debugfp); |
297 | #endif |
298 | |
d3409d5e |
299 | /* --- Get rid of this node now --- */ |
300 | |
301 | DESTROY(n); |
97d21728 |
302 | a->n++; |
d3409d5e |
303 | return (v + 1); |
304 | } |
305 | |
12a9a6e5 |
306 | #endif |
307 | |
d3409d5e |
308 | /* --- @mpfree@ --- * |
309 | * |
310 | * Arguments: @mparena *a@ = pointer to arena block |
311 | * @mpw *v@ = pointer to allocated vector |
312 | * |
313 | * Returns: --- |
314 | * |
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315 | * Use: Returns an MP vector to an arena. |
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316 | */ |
317 | |
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318 | #ifdef MPARENA_TRIVIAL |
319 | |
320 | void mpfree(mparena *a, mpw *v) |
321 | { |
02d7884d |
322 | if (!v) return; |
323 | a->n--; |
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324 | A_FREE(a->a, v); |
12a9a6e5 |
325 | } |
326 | |
327 | #else |
328 | |
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329 | void mpfree(mparena *a, mpw *v) |
330 | { |
331 | mparena_node **nn, *n; |
332 | size_t sz = *--v; |
333 | |
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334 | #ifdef MPARENA_DEBUG |
335 | MPARENA_OPENFILE; |
336 | fprintf(debugfp, "free %u\n before: ", sz); |
337 | tdump(a->root); putc('\n', debugfp); |
338 | #endif |
339 | |
340 | nn = &a->root; |
d3409d5e |
341 | while (*nn) { |
342 | n = *nn; |
343 | if (n->v[0] > sz) |
344 | nn = &n->left; |
345 | else |
346 | nn = &n->right; |
347 | } |
348 | |
349 | n = CREATE(mparena_node); |
350 | n->left = n->right = 0; |
351 | n->v = v; |
352 | *nn = n; |
97d21728 |
353 | a->n--; |
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354 | |
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355 | #ifdef MPARENA_DEBUG |
356 | fputs(" after: ", debugfp); |
357 | tdump(a->root); putc('\n', debugfp); |
d3409d5e |
358 | #endif |
359 | } |
360 | |
12a9a6e5 |
361 | #endif |
362 | |
d3409d5e |
363 | /*----- That's all, folks -------------------------------------------------*/ |