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1 | /* -*-c-*- |
2 | * |
d34decd2 |
3 | * $Id: mp-mem.c,v 1.3 2000/06/17 11:45:09 mdw Exp $ |
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4 | * |
5 | * Memory management for multiprecision numbers |
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: mp-mem.c,v $ |
d34decd2 |
33 | * Revision 1.3 2000/06/17 11:45:09 mdw |
34 | * Major memory management overhaul. Added arena support. Use the secure |
35 | * arena for secret integers. Replace and improve the MP management macros |
36 | * (e.g., replace MP_MODIFY by MP_DEST). |
37 | * |
0e895689 |
38 | * Revision 1.2 1999/12/10 23:19:02 mdw |
39 | * Improve error-checking. |
40 | * |
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41 | * Revision 1.1 1999/11/17 18:02:16 mdw |
42 | * New multiprecision integer arithmetic suite. |
43 | * |
44 | */ |
45 | |
46 | /*----- Header files ------------------------------------------------------*/ |
47 | |
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48 | #include <mLib/sub.h> |
49 | |
50 | |
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51 | #include "mp.h" |
52 | |
53 | /*----- Main code ---------------------------------------------------------*/ |
54 | |
d34decd2 |
55 | /* --- @mp_new@ --- * |
56 | * |
57 | * Arguments: @size_t sz@ = size of vector required |
58 | * @unsigned f@ = flags to set |
59 | * |
60 | * Returns: Pointer to a new MP structure. |
61 | * |
62 | * Use: Allocates a new multiprecision integer. The data space is |
63 | * allocated from either the standard global or secret arena, |
64 | * depending on the initial flags requested. |
65 | */ |
66 | |
67 | mp *mp_new(size_t sz, unsigned f) |
68 | { |
69 | mp *m = CREATE(mp); |
70 | m->a = (f & MP_BURN) ? MPARENA_SECURE : MPARENA_GLOBAL; |
71 | m->v = mpalloc(m->a, sz); |
72 | m->vl = m->v + sz; |
73 | m->sz = sz; |
74 | m->f = f & ~(MP_CONST | MP_DESTROYED); |
75 | m->ref = 1; |
76 | return (m); |
77 | } |
78 | |
d3409d5e |
79 | /* --- @mp_create@ --- * |
80 | * |
81 | * Arguments: @size_t sz@ = size of vector required |
82 | * |
83 | * Returns: Pointer to pristine new MP structure with enough memory |
84 | * bolted onto it. |
85 | * |
86 | * Use: Creates a new multiprecision integer, initially zero. The |
87 | * integer has a single reference. |
88 | */ |
89 | |
90 | mp *mp_create(size_t sz) |
91 | { |
92 | mp *m = CREATE(mp); |
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93 | m->v = mpalloc(MPARENA_GLOBAL, sz); |
d3409d5e |
94 | m->vl = m->v + sz; |
95 | m->sz = sz; |
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96 | m->a = MPARENA_GLOBAL; |
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97 | m->f = MP_UNDEF; |
98 | m->ref = 1; |
99 | return (m); |
100 | } |
101 | |
d34decd2 |
102 | /* --- @mp_createsecure@ --- * |
103 | * |
104 | * Arguments: @size_t sz@ = size of vector required |
105 | * |
106 | * Returns: Pointer to pristine new MP structure with enough memory |
107 | * bolted onto it. |
108 | * |
109 | * Use: Creates a new multiprecision integer with indeterminate |
110 | * contents. The integer has a single reference. The integer's |
111 | * data space is allocated from the secure arena. Its burn flag |
112 | * is set. |
113 | */ |
114 | |
115 | mp *mp_createsecure(size_t sz) |
116 | { |
117 | mp *m = CREATE(mp); |
118 | m->v = mpalloc(MPARENA_SECURE, sz); |
119 | m->vl = m->v + sz; |
120 | m->sz = sz; |
121 | m->a = MPARENA_SECURE; |
122 | m->f = MP_UNDEF | MP_BURN; |
123 | m->ref = 1; |
124 | return (m); |
125 | } |
126 | |
d3409d5e |
127 | /* --- @mp_build@ --- * |
128 | * |
129 | * Arguments: @mp *m@ = pointer to an MP block to fill in |
130 | * @mpw *v@ = pointer to a word array |
131 | * @mpw *vl@ = pointer just past end of array |
132 | * |
133 | * Returns: --- |
134 | * |
135 | * Use: Creates a multiprecision integer representing some smallish |
136 | * number. You must provide storage for the number and dispose |
137 | * of it when you've finished with it. The number is marked as |
138 | * constant while it exists. |
139 | */ |
140 | |
141 | void mp_build(mp *m, mpw *v, mpw *vl) |
142 | { |
143 | m->v = v; |
144 | m->vl = vl; |
145 | m->sz = vl - v; |
146 | m->f = MP_CONST; |
147 | m->ref = 1; |
148 | } |
149 | |
150 | /* --- @mp_destroy@ --- * |
151 | * |
152 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
153 | * |
154 | * Returns: --- |
155 | * |
156 | * Use: Destroys a multiprecision integer. The reference count isn't |
157 | * checked. Don't use this function if you don't know what |
158 | * you're doing: use @mp_drop@ instead. |
159 | */ |
160 | |
161 | void mp_destroy(mp *m) |
162 | { |
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163 | assert(((void)"Destroying a free integer", !(m->f & MP_DESTROYED))); |
164 | assert(((void)"Attempted to destroy a constant", !(m->f & MP_CONST))); |
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165 | if (m->f & MP_BURN) |
166 | memset(m->v, 0, MPWS(m->sz)); |
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167 | mpfree(m->a, m->v); |
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168 | m->f |= MP_DESTROYED; |
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169 | DESTROY(m); |
170 | } |
171 | |
172 | /* --- @mp_copy@ --- * |
173 | * |
174 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
175 | * |
176 | * Returns: A copy of the given multiprecision integer. |
177 | * |
178 | * Use: Copies the given integer. In fact you just get another |
179 | * reference to the same old one again. |
180 | */ |
181 | |
182 | mp *mp_copy(mp *m) { return MP_COPY(m); } |
183 | |
184 | /* --- @mp_drop@ --- * |
185 | * |
186 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
187 | * |
188 | * Returns: --- |
189 | * |
190 | * Use: Drops a reference to an integer which isn't wanted any more. |
191 | * If there are no more references, the integer is destroyed. |
192 | */ |
193 | |
194 | void mp_drop(mp *m) { MP_DROP(m); } |
195 | |
196 | /* --- @mp_split@ --- * |
197 | * |
198 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
199 | * |
200 | * Returns: A reference to the same integer, possibly with a different |
201 | * address. |
202 | * |
203 | * Use: Splits off a modifiable version of the integer referred to. |
204 | */ |
205 | |
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206 | mp *mp_split(mp *m) |
207 | { |
208 | /* if ((m->f & MP_CONST) || m->ref > 1) { */ |
209 | /* size_t len = MP_LEN(m); */ |
210 | /* mp *mm = mp_new(len, m->f); */ |
211 | /* if (!(m->f & MP_UNDEF)) */ |
212 | /* memcpy(mm->v, m->v, MPWS(len)); */ |
213 | /* m->ref--; */ |
214 | /* m = mm; */ |
215 | /* } */ |
216 | MP_SPLIT(m); |
217 | return (m); |
218 | } |
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219 | |
220 | /* --- @mp_resize@ --- * |
221 | * |
222 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
223 | * @size_t sz@ = new size |
224 | * |
225 | * Returns: --- |
226 | * |
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227 | * Use: Changes an integer's size. The length and value are not |
228 | * changed. It is an error to |
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229 | */ |
230 | |
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231 | void mp_resize(mp *m, size_t sz) |
232 | { |
233 | /* mparena *a = (m->f & MP_BURN) ? MPARENA_SECURE : MPARENA_GLOBAL; */ |
234 | /* mpw *v; */ |
235 | /* size_t len = MP_LEN(m); */ |
236 | /* assert(((void)"can't make size less than length", sz >= len)); */ |
237 | /* v = mpalloc(a, sz); */ |
238 | /* if (!(m->f & MP_UNDEF)) */ |
239 | /* memcpy(v, m->v, MPWS(len)); */ |
240 | /* if (m->f & MP_BURN) */ |
241 | /* memset(m->v, 0, MPWS(m->sz)); */ |
242 | /* mpfree(m->a, m->v); */ |
243 | /* m->a = a; */ |
244 | /* m->v = v; */ |
245 | /* m->vl = v + len; */ |
246 | } |
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247 | |
248 | /* --- @mp_ensure@ --- * |
249 | * |
250 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
d34decd2 |
251 | * @size_t sz@ = required length |
d3409d5e |
252 | * |
253 | * Returns: --- |
254 | * |
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255 | * Use: Changes an integer's length. If there is not enough space |
256 | * allocated for the new length then the size is increased. It |
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257 | */ |
258 | |
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259 | void mp_ensure(mp *m, size_t sz) |
260 | { |
261 | /* size_t len = MP_LEN(m); */ |
262 | /* if (sz >= len) { */ |
263 | /* if (sz > m->sz) */ |
264 | /* mp_resize(m, sz); */ |
265 | /* if (!(m->f & MP_UNDEF) && sz > len) */ |
266 | /* memset(m->vl, 0, MPWS(sz - len)); */ |
267 | /* m->vl = m->v + sz; */ |
268 | /* } */ |
269 | } |
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270 | |
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271 | /* --- @mp_dest@ --- * |
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272 | * |
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273 | * Arguments: @mp *m@ = a suggested destination integer |
274 | * @size_t sz@ = size required for result, in digits |
275 | * @unsigned f@ = various flags |
276 | * |
277 | * Returns: A pointer to an appropriate destination. |
278 | * |
279 | * Use: Converts a suggested destination into a real destination with |
280 | * the required properties. If the real destination is @d@, |
281 | * then the following properties will hold: |
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282 | * |
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283 | * * @d@ will have exactly one reference. |
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284 | * |
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285 | * * If @m@ is not @MP_NEW@, then the contents of @m@ will not |
286 | * change, unless @f@ has the @MP_UNDEF@ flag set. |
287 | * |
288 | * * If @m@ is not @MP_NEW@, then he reference count of @m@ on |
289 | * entry is equal to the sum of the counts of @d@ and @m@ on |
290 | * exit. |
291 | * |
292 | * * The size of @d@ will be at least @sz@. |
293 | * |
294 | * * If @f@ has the @MP_BURN@ flag set, then @d@ will be |
295 | * allocated from @MPARENA_SECURE@. |
296 | * |
297 | * Understanding this function is crucial to using Catacomb's |
298 | * multiprecision integer library effectively. |
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299 | */ |
300 | |
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301 | mp *mp_dest(mp *m, size_t sz, unsigned f) |
302 | { |
303 | /* --- If no destination, make one --- */ |
304 | |
305 | if (m == MP_NEWSEC) |
306 | m = mp_new(sz, f | MP_UNDEF | MP_BURN); |
307 | else if (m == MP_NEW) |
308 | m = mp_new(sz, f | MP_UNDEF); |
309 | else { |
310 | size_t len = MP_LEN(m); |
311 | unsigned undef = (m->f | f) & MP_UNDEF; |
312 | |
313 | /* --- If the value must be preserved, the block can't shrink --- */ |
314 | |
315 | if (!undef && sz < len) |
316 | sz = len; |
317 | |
318 | /* --- Otherwise check whether the destination is suitable --- */ |
319 | |
320 | if (m->ref > 1 || (m->f & MP_CONST) || |
321 | m->sz > len || !((f & ~m->f) & MP_BURN)) { |
322 | |
323 | /* --- No -- allocate a new buffer --- * |
324 | * |
325 | * The buffer must be secure if (a) the caller requested a secure |
326 | * buffer, or (b) the old buffer is secure and I'm not allowed to |
327 | * discard the old contents. |
328 | */ |
329 | |
330 | mparena *a; |
331 | mpw *v; |
332 | |
333 | if ((f & MP_BURN) || (!undef && (m->f & MP_BURN))) |
334 | a = MPARENA_SECURE; |
335 | else |
336 | a = MPARENA_GLOBAL; |
337 | v = mpalloc(a, sz); |
338 | |
339 | /* --- Copy the data over --- */ |
340 | |
341 | if (!undef) { |
342 | memcpy(v, m->v, MPWS(len)); |
343 | if (sz - len > 0) |
344 | memset(v + len, 0, MPWS(sz - len)); |
345 | } |
346 | |
347 | /* --- If @m@ has other references, make a new node --- * |
348 | * |
349 | * Otherwise dispose of the old buffer. |
350 | */ |
351 | |
352 | if (!(m->f & MP_CONST) && m->ref == 1) { |
353 | if (m->f & MP_BURN) |
354 | memset(m->v, 0, MPWS(m->sz)); |
355 | mpfree(m->a, m->v); |
356 | } else { |
357 | mp *mm = CREATE(mp); |
358 | mm->ref = 1; |
359 | mm->f = m->f; |
360 | m->ref--; |
361 | m = mm; |
362 | } |
363 | |
364 | /* --- Fix up the node --- */ |
365 | |
366 | m->v = v; |
367 | m->vl = v + sz; |
368 | m->sz = sz; |
369 | m->f = ((m->f & ~(MP_CONST | MP_BURN)) | |
370 | (f & (MP_BURN | MP_UNDEF))); |
371 | m->a = a; |
372 | } |
373 | |
374 | /* --- If the number is growing in its buffer, fix it up --- */ |
375 | |
376 | else if (sz > len) { |
377 | if (!undef) |
378 | memset(m->vl, 0, MPWS(sz - len)); |
379 | m->vl = m->v + sz; |
380 | } |
381 | } |
382 | |
383 | /* --- Done --- */ |
384 | |
385 | return (m); |
386 | } |
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387 | |
388 | /*----- That's all, folks -------------------------------------------------*/ |