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1 | /* -*-c-*- |
2 | * |
f1140c41 |
3 | * $Id: mp-mem.c,v 1.4 2001/02/03 12:00:29 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 $ |
f1140c41 |
33 | * Revision 1.4 2001/02/03 12:00:29 mdw |
34 | * Now @mp_drop@ checks its argument is non-NULL before attempting to free |
35 | * it. Note that the macro version @MP_DROP@ doesn't do this. |
36 | * |
d34decd2 |
37 | * Revision 1.3 2000/06/17 11:45:09 mdw |
38 | * Major memory management overhaul. Added arena support. Use the secure |
39 | * arena for secret integers. Replace and improve the MP management macros |
40 | * (e.g., replace MP_MODIFY by MP_DEST). |
41 | * |
0e895689 |
42 | * Revision 1.2 1999/12/10 23:19:02 mdw |
43 | * Improve error-checking. |
44 | * |
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45 | * Revision 1.1 1999/11/17 18:02:16 mdw |
46 | * New multiprecision integer arithmetic suite. |
47 | * |
48 | */ |
49 | |
50 | /*----- Header files ------------------------------------------------------*/ |
51 | |
d34decd2 |
52 | #include <mLib/sub.h> |
53 | |
54 | |
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55 | #include "mp.h" |
56 | |
57 | /*----- Main code ---------------------------------------------------------*/ |
58 | |
d34decd2 |
59 | /* --- @mp_new@ --- * |
60 | * |
61 | * Arguments: @size_t sz@ = size of vector required |
62 | * @unsigned f@ = flags to set |
63 | * |
64 | * Returns: Pointer to a new MP structure. |
65 | * |
66 | * Use: Allocates a new multiprecision integer. The data space is |
67 | * allocated from either the standard global or secret arena, |
68 | * depending on the initial flags requested. |
69 | */ |
70 | |
71 | mp *mp_new(size_t sz, unsigned f) |
72 | { |
73 | mp *m = CREATE(mp); |
74 | m->a = (f & MP_BURN) ? MPARENA_SECURE : MPARENA_GLOBAL; |
75 | m->v = mpalloc(m->a, sz); |
76 | m->vl = m->v + sz; |
77 | m->sz = sz; |
78 | m->f = f & ~(MP_CONST | MP_DESTROYED); |
79 | m->ref = 1; |
80 | return (m); |
81 | } |
82 | |
d3409d5e |
83 | /* --- @mp_create@ --- * |
84 | * |
85 | * Arguments: @size_t sz@ = size of vector required |
86 | * |
87 | * Returns: Pointer to pristine new MP structure with enough memory |
88 | * bolted onto it. |
89 | * |
90 | * Use: Creates a new multiprecision integer, initially zero. The |
91 | * integer has a single reference. |
92 | */ |
93 | |
94 | mp *mp_create(size_t sz) |
95 | { |
96 | mp *m = CREATE(mp); |
d34decd2 |
97 | m->v = mpalloc(MPARENA_GLOBAL, sz); |
d3409d5e |
98 | m->vl = m->v + sz; |
99 | m->sz = sz; |
d34decd2 |
100 | m->a = MPARENA_GLOBAL; |
d3409d5e |
101 | m->f = MP_UNDEF; |
102 | m->ref = 1; |
103 | return (m); |
104 | } |
105 | |
d34decd2 |
106 | /* --- @mp_createsecure@ --- * |
107 | * |
108 | * Arguments: @size_t sz@ = size of vector required |
109 | * |
110 | * Returns: Pointer to pristine new MP structure with enough memory |
111 | * bolted onto it. |
112 | * |
113 | * Use: Creates a new multiprecision integer with indeterminate |
114 | * contents. The integer has a single reference. The integer's |
115 | * data space is allocated from the secure arena. Its burn flag |
116 | * is set. |
117 | */ |
118 | |
119 | mp *mp_createsecure(size_t sz) |
120 | { |
121 | mp *m = CREATE(mp); |
122 | m->v = mpalloc(MPARENA_SECURE, sz); |
123 | m->vl = m->v + sz; |
124 | m->sz = sz; |
125 | m->a = MPARENA_SECURE; |
126 | m->f = MP_UNDEF | MP_BURN; |
127 | m->ref = 1; |
128 | return (m); |
129 | } |
130 | |
d3409d5e |
131 | /* --- @mp_build@ --- * |
132 | * |
133 | * Arguments: @mp *m@ = pointer to an MP block to fill in |
134 | * @mpw *v@ = pointer to a word array |
135 | * @mpw *vl@ = pointer just past end of array |
136 | * |
137 | * Returns: --- |
138 | * |
139 | * Use: Creates a multiprecision integer representing some smallish |
140 | * number. You must provide storage for the number and dispose |
141 | * of it when you've finished with it. The number is marked as |
142 | * constant while it exists. |
143 | */ |
144 | |
145 | void mp_build(mp *m, mpw *v, mpw *vl) |
146 | { |
147 | m->v = v; |
148 | m->vl = vl; |
149 | m->sz = vl - v; |
150 | m->f = MP_CONST; |
151 | m->ref = 1; |
152 | } |
153 | |
154 | /* --- @mp_destroy@ --- * |
155 | * |
156 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
157 | * |
158 | * Returns: --- |
159 | * |
160 | * Use: Destroys a multiprecision integer. The reference count isn't |
161 | * checked. Don't use this function if you don't know what |
162 | * you're doing: use @mp_drop@ instead. |
163 | */ |
164 | |
165 | void mp_destroy(mp *m) |
166 | { |
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167 | assert(((void)"Destroying a free integer", !(m->f & MP_DESTROYED))); |
168 | assert(((void)"Attempted to destroy a constant", !(m->f & MP_CONST))); |
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169 | if (m->f & MP_BURN) |
170 | memset(m->v, 0, MPWS(m->sz)); |
d34decd2 |
171 | mpfree(m->a, m->v); |
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172 | m->f |= MP_DESTROYED; |
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173 | DESTROY(m); |
174 | } |
175 | |
176 | /* --- @mp_copy@ --- * |
177 | * |
178 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
179 | * |
180 | * Returns: A copy of the given multiprecision integer. |
181 | * |
182 | * Use: Copies the given integer. In fact you just get another |
183 | * reference to the same old one again. |
184 | */ |
185 | |
186 | mp *mp_copy(mp *m) { return MP_COPY(m); } |
187 | |
188 | /* --- @mp_drop@ --- * |
189 | * |
190 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
191 | * |
192 | * Returns: --- |
193 | * |
194 | * Use: Drops a reference to an integer which isn't wanted any more. |
195 | * If there are no more references, the integer is destroyed. |
196 | */ |
197 | |
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198 | void mp_drop(mp *m) { if (m) MP_DROP(m); } |
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199 | |
200 | /* --- @mp_split@ --- * |
201 | * |
202 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
203 | * |
204 | * Returns: A reference to the same integer, possibly with a different |
205 | * address. |
206 | * |
207 | * Use: Splits off a modifiable version of the integer referred to. |
208 | */ |
209 | |
d34decd2 |
210 | mp *mp_split(mp *m) |
211 | { |
212 | /* if ((m->f & MP_CONST) || m->ref > 1) { */ |
213 | /* size_t len = MP_LEN(m); */ |
214 | /* mp *mm = mp_new(len, m->f); */ |
215 | /* if (!(m->f & MP_UNDEF)) */ |
216 | /* memcpy(mm->v, m->v, MPWS(len)); */ |
217 | /* m->ref--; */ |
218 | /* m = mm; */ |
219 | /* } */ |
220 | MP_SPLIT(m); |
221 | return (m); |
222 | } |
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223 | |
224 | /* --- @mp_resize@ --- * |
225 | * |
226 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
227 | * @size_t sz@ = new size |
228 | * |
229 | * Returns: --- |
230 | * |
d34decd2 |
231 | * Use: Changes an integer's size. The length and value are not |
232 | * changed. It is an error to |
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233 | */ |
234 | |
d34decd2 |
235 | void mp_resize(mp *m, size_t sz) |
236 | { |
237 | /* mparena *a = (m->f & MP_BURN) ? MPARENA_SECURE : MPARENA_GLOBAL; */ |
238 | /* mpw *v; */ |
239 | /* size_t len = MP_LEN(m); */ |
240 | /* assert(((void)"can't make size less than length", sz >= len)); */ |
241 | /* v = mpalloc(a, sz); */ |
242 | /* if (!(m->f & MP_UNDEF)) */ |
243 | /* memcpy(v, m->v, MPWS(len)); */ |
244 | /* if (m->f & MP_BURN) */ |
245 | /* memset(m->v, 0, MPWS(m->sz)); */ |
246 | /* mpfree(m->a, m->v); */ |
247 | /* m->a = a; */ |
248 | /* m->v = v; */ |
249 | /* m->vl = v + len; */ |
250 | } |
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251 | |
252 | /* --- @mp_ensure@ --- * |
253 | * |
254 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
d34decd2 |
255 | * @size_t sz@ = required length |
d3409d5e |
256 | * |
257 | * Returns: --- |
258 | * |
d34decd2 |
259 | * Use: Changes an integer's length. If there is not enough space |
260 | * allocated for the new length then the size is increased. It |
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261 | */ |
262 | |
d34decd2 |
263 | void mp_ensure(mp *m, size_t sz) |
264 | { |
265 | /* size_t len = MP_LEN(m); */ |
266 | /* if (sz >= len) { */ |
267 | /* if (sz > m->sz) */ |
268 | /* mp_resize(m, sz); */ |
269 | /* if (!(m->f & MP_UNDEF) && sz > len) */ |
270 | /* memset(m->vl, 0, MPWS(sz - len)); */ |
271 | /* m->vl = m->v + sz; */ |
272 | /* } */ |
273 | } |
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274 | |
d34decd2 |
275 | /* --- @mp_dest@ --- * |
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276 | * |
d34decd2 |
277 | * Arguments: @mp *m@ = a suggested destination integer |
278 | * @size_t sz@ = size required for result, in digits |
279 | * @unsigned f@ = various flags |
280 | * |
281 | * Returns: A pointer to an appropriate destination. |
282 | * |
283 | * Use: Converts a suggested destination into a real destination with |
284 | * the required properties. If the real destination is @d@, |
285 | * then the following properties will hold: |
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286 | * |
d34decd2 |
287 | * * @d@ will have exactly one reference. |
d3409d5e |
288 | * |
d34decd2 |
289 | * * If @m@ is not @MP_NEW@, then the contents of @m@ will not |
290 | * change, unless @f@ has the @MP_UNDEF@ flag set. |
291 | * |
292 | * * If @m@ is not @MP_NEW@, then he reference count of @m@ on |
293 | * entry is equal to the sum of the counts of @d@ and @m@ on |
294 | * exit. |
295 | * |
296 | * * The size of @d@ will be at least @sz@. |
297 | * |
298 | * * If @f@ has the @MP_BURN@ flag set, then @d@ will be |
299 | * allocated from @MPARENA_SECURE@. |
300 | * |
301 | * Understanding this function is crucial to using Catacomb's |
302 | * multiprecision integer library effectively. |
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303 | */ |
304 | |
d34decd2 |
305 | mp *mp_dest(mp *m, size_t sz, unsigned f) |
306 | { |
307 | /* --- If no destination, make one --- */ |
308 | |
309 | if (m == MP_NEWSEC) |
310 | m = mp_new(sz, f | MP_UNDEF | MP_BURN); |
311 | else if (m == MP_NEW) |
312 | m = mp_new(sz, f | MP_UNDEF); |
313 | else { |
314 | size_t len = MP_LEN(m); |
315 | unsigned undef = (m->f | f) & MP_UNDEF; |
316 | |
317 | /* --- If the value must be preserved, the block can't shrink --- */ |
318 | |
319 | if (!undef && sz < len) |
320 | sz = len; |
321 | |
322 | /* --- Otherwise check whether the destination is suitable --- */ |
323 | |
324 | if (m->ref > 1 || (m->f & MP_CONST) || |
325 | m->sz > len || !((f & ~m->f) & MP_BURN)) { |
326 | |
327 | /* --- No -- allocate a new buffer --- * |
328 | * |
329 | * The buffer must be secure if (a) the caller requested a secure |
330 | * buffer, or (b) the old buffer is secure and I'm not allowed to |
331 | * discard the old contents. |
332 | */ |
333 | |
334 | mparena *a; |
335 | mpw *v; |
336 | |
337 | if ((f & MP_BURN) || (!undef && (m->f & MP_BURN))) |
338 | a = MPARENA_SECURE; |
339 | else |
340 | a = MPARENA_GLOBAL; |
341 | v = mpalloc(a, sz); |
342 | |
343 | /* --- Copy the data over --- */ |
344 | |
345 | if (!undef) { |
346 | memcpy(v, m->v, MPWS(len)); |
347 | if (sz - len > 0) |
348 | memset(v + len, 0, MPWS(sz - len)); |
349 | } |
350 | |
351 | /* --- If @m@ has other references, make a new node --- * |
352 | * |
353 | * Otherwise dispose of the old buffer. |
354 | */ |
355 | |
356 | if (!(m->f & MP_CONST) && m->ref == 1) { |
357 | if (m->f & MP_BURN) |
358 | memset(m->v, 0, MPWS(m->sz)); |
359 | mpfree(m->a, m->v); |
360 | } else { |
361 | mp *mm = CREATE(mp); |
362 | mm->ref = 1; |
363 | mm->f = m->f; |
364 | m->ref--; |
365 | m = mm; |
366 | } |
367 | |
368 | /* --- Fix up the node --- */ |
369 | |
370 | m->v = v; |
371 | m->vl = v + sz; |
372 | m->sz = sz; |
373 | m->f = ((m->f & ~(MP_CONST | MP_BURN)) | |
374 | (f & (MP_BURN | MP_UNDEF))); |
375 | m->a = a; |
376 | } |
377 | |
378 | /* --- If the number is growing in its buffer, fix it up --- */ |
379 | |
380 | else if (sz > len) { |
381 | if (!undef) |
382 | memset(m->vl, 0, MPWS(sz - len)); |
383 | m->vl = m->v + sz; |
384 | } |
385 | } |
386 | |
387 | /* --- Done --- */ |
388 | |
389 | return (m); |
390 | } |
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391 | |
392 | /*----- That's all, folks -------------------------------------------------*/ |