d3409d5e |
1 | /* -*-c-*- |
2 | * |
24521163 |
3 | * $Id: mp-mem.c,v 1.5 2001/06/16 12:57:00 mdw Exp $ |
d3409d5e |
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 $ |
24521163 |
33 | * Revision 1.5 2001/06/16 12:57:00 mdw |
34 | * Implement some missing functions. |
35 | * |
f1140c41 |
36 | * Revision 1.4 2001/02/03 12:00:29 mdw |
37 | * Now @mp_drop@ checks its argument is non-NULL before attempting to free |
38 | * it. Note that the macro version @MP_DROP@ doesn't do this. |
39 | * |
d34decd2 |
40 | * Revision 1.3 2000/06/17 11:45:09 mdw |
41 | * Major memory management overhaul. Added arena support. Use the secure |
42 | * arena for secret integers. Replace and improve the MP management macros |
43 | * (e.g., replace MP_MODIFY by MP_DEST). |
44 | * |
0e895689 |
45 | * Revision 1.2 1999/12/10 23:19:02 mdw |
46 | * Improve error-checking. |
47 | * |
d3409d5e |
48 | * Revision 1.1 1999/11/17 18:02:16 mdw |
49 | * New multiprecision integer arithmetic suite. |
50 | * |
51 | */ |
52 | |
53 | /*----- Header files ------------------------------------------------------*/ |
54 | |
d34decd2 |
55 | #include <mLib/sub.h> |
56 | |
57 | |
d3409d5e |
58 | #include "mp.h" |
59 | |
60 | /*----- Main code ---------------------------------------------------------*/ |
61 | |
d34decd2 |
62 | /* --- @mp_new@ --- * |
63 | * |
64 | * Arguments: @size_t sz@ = size of vector required |
65 | * @unsigned f@ = flags to set |
66 | * |
67 | * Returns: Pointer to a new MP structure. |
68 | * |
69 | * Use: Allocates a new multiprecision integer. The data space is |
70 | * allocated from either the standard global or secret arena, |
71 | * depending on the initial flags requested. |
72 | */ |
73 | |
74 | mp *mp_new(size_t sz, unsigned f) |
75 | { |
76 | mp *m = CREATE(mp); |
77 | m->a = (f & MP_BURN) ? MPARENA_SECURE : MPARENA_GLOBAL; |
78 | m->v = mpalloc(m->a, sz); |
79 | m->vl = m->v + sz; |
80 | m->sz = sz; |
81 | m->f = f & ~(MP_CONST | MP_DESTROYED); |
82 | m->ref = 1; |
83 | return (m); |
84 | } |
85 | |
d3409d5e |
86 | /* --- @mp_create@ --- * |
87 | * |
88 | * Arguments: @size_t sz@ = size of vector required |
89 | * |
90 | * Returns: Pointer to pristine new MP structure with enough memory |
91 | * bolted onto it. |
92 | * |
93 | * Use: Creates a new multiprecision integer, initially zero. The |
94 | * integer has a single reference. |
95 | */ |
96 | |
97 | mp *mp_create(size_t sz) |
98 | { |
99 | mp *m = CREATE(mp); |
d34decd2 |
100 | m->v = mpalloc(MPARENA_GLOBAL, sz); |
d3409d5e |
101 | m->vl = m->v + sz; |
102 | m->sz = sz; |
d34decd2 |
103 | m->a = MPARENA_GLOBAL; |
d3409d5e |
104 | m->f = MP_UNDEF; |
105 | m->ref = 1; |
106 | return (m); |
107 | } |
108 | |
d34decd2 |
109 | /* --- @mp_createsecure@ --- * |
110 | * |
111 | * Arguments: @size_t sz@ = size of vector required |
112 | * |
113 | * Returns: Pointer to pristine new MP structure with enough memory |
114 | * bolted onto it. |
115 | * |
116 | * Use: Creates a new multiprecision integer with indeterminate |
117 | * contents. The integer has a single reference. The integer's |
118 | * data space is allocated from the secure arena. Its burn flag |
119 | * is set. |
120 | */ |
121 | |
122 | mp *mp_createsecure(size_t sz) |
123 | { |
124 | mp *m = CREATE(mp); |
125 | m->v = mpalloc(MPARENA_SECURE, sz); |
126 | m->vl = m->v + sz; |
127 | m->sz = sz; |
128 | m->a = MPARENA_SECURE; |
129 | m->f = MP_UNDEF | MP_BURN; |
130 | m->ref = 1; |
131 | return (m); |
132 | } |
133 | |
d3409d5e |
134 | /* --- @mp_build@ --- * |
135 | * |
136 | * Arguments: @mp *m@ = pointer to an MP block to fill in |
137 | * @mpw *v@ = pointer to a word array |
138 | * @mpw *vl@ = pointer just past end of array |
139 | * |
140 | * Returns: --- |
141 | * |
142 | * Use: Creates a multiprecision integer representing some smallish |
143 | * number. You must provide storage for the number and dispose |
144 | * of it when you've finished with it. The number is marked as |
145 | * constant while it exists. |
146 | */ |
147 | |
148 | void mp_build(mp *m, mpw *v, mpw *vl) |
149 | { |
150 | m->v = v; |
151 | m->vl = vl; |
152 | m->sz = vl - v; |
153 | m->f = MP_CONST; |
154 | m->ref = 1; |
155 | } |
156 | |
157 | /* --- @mp_destroy@ --- * |
158 | * |
159 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
160 | * |
161 | * Returns: --- |
162 | * |
163 | * Use: Destroys a multiprecision integer. The reference count isn't |
164 | * checked. Don't use this function if you don't know what |
165 | * you're doing: use @mp_drop@ instead. |
166 | */ |
167 | |
168 | void mp_destroy(mp *m) |
169 | { |
0e895689 |
170 | assert(((void)"Destroying a free integer", !(m->f & MP_DESTROYED))); |
171 | assert(((void)"Attempted to destroy a constant", !(m->f & MP_CONST))); |
d3409d5e |
172 | if (m->f & MP_BURN) |
173 | memset(m->v, 0, MPWS(m->sz)); |
d34decd2 |
174 | mpfree(m->a, m->v); |
0e895689 |
175 | m->f |= MP_DESTROYED; |
d3409d5e |
176 | DESTROY(m); |
177 | } |
178 | |
179 | /* --- @mp_copy@ --- * |
180 | * |
181 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
182 | * |
183 | * Returns: A copy of the given multiprecision integer. |
184 | * |
185 | * Use: Copies the given integer. In fact you just get another |
186 | * reference to the same old one again. |
187 | */ |
188 | |
189 | mp *mp_copy(mp *m) { return MP_COPY(m); } |
190 | |
191 | /* --- @mp_drop@ --- * |
192 | * |
193 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
194 | * |
195 | * Returns: --- |
196 | * |
197 | * Use: Drops a reference to an integer which isn't wanted any more. |
198 | * If there are no more references, the integer is destroyed. |
199 | */ |
200 | |
f1140c41 |
201 | void mp_drop(mp *m) { if (m) MP_DROP(m); } |
d3409d5e |
202 | |
203 | /* --- @mp_split@ --- * |
204 | * |
205 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
206 | * |
207 | * Returns: A reference to the same integer, possibly with a different |
208 | * address. |
209 | * |
210 | * Use: Splits off a modifiable version of the integer referred to. |
211 | */ |
212 | |
24521163 |
213 | mp *mp_split(mp *m) { MP_SPLIT(m); return (m); } |
d3409d5e |
214 | |
215 | /* --- @mp_resize@ --- * |
216 | * |
217 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
218 | * @size_t sz@ = new size |
219 | * |
220 | * Returns: --- |
221 | * |
d34decd2 |
222 | * Use: Changes an integer's size. The length and value are not |
223 | * changed. It is an error to |
d3409d5e |
224 | */ |
225 | |
24521163 |
226 | void mp_resize(mp *m, size_t sz) { MP_RESIZE(m, sz); } |
d3409d5e |
227 | |
228 | /* --- @mp_ensure@ --- * |
229 | * |
230 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
d34decd2 |
231 | * @size_t sz@ = required length |
d3409d5e |
232 | * |
233 | * Returns: --- |
234 | * |
d34decd2 |
235 | * Use: Changes an integer's length. If there is not enough space |
236 | * allocated for the new length then the size is increased. It |
d3409d5e |
237 | */ |
238 | |
24521163 |
239 | void mp_ensure(mp *m, size_t sz) { MP_ENSURE(m, sz); } |
d3409d5e |
240 | |
d34decd2 |
241 | /* --- @mp_dest@ --- * |
d3409d5e |
242 | * |
d34decd2 |
243 | * Arguments: @mp *m@ = a suggested destination integer |
244 | * @size_t sz@ = size required for result, in digits |
245 | * @unsigned f@ = various flags |
246 | * |
247 | * Returns: A pointer to an appropriate destination. |
248 | * |
249 | * Use: Converts a suggested destination into a real destination with |
250 | * the required properties. If the real destination is @d@, |
251 | * then the following properties will hold: |
d3409d5e |
252 | * |
d34decd2 |
253 | * * @d@ will have exactly one reference. |
d3409d5e |
254 | * |
d34decd2 |
255 | * * If @m@ is not @MP_NEW@, then the contents of @m@ will not |
256 | * change, unless @f@ has the @MP_UNDEF@ flag set. |
257 | * |
258 | * * If @m@ is not @MP_NEW@, then he reference count of @m@ on |
259 | * entry is equal to the sum of the counts of @d@ and @m@ on |
260 | * exit. |
261 | * |
262 | * * The size of @d@ will be at least @sz@. |
263 | * |
264 | * * If @f@ has the @MP_BURN@ flag set, then @d@ will be |
265 | * allocated from @MPARENA_SECURE@. |
266 | * |
267 | * Understanding this function is crucial to using Catacomb's |
268 | * multiprecision integer library effectively. |
d3409d5e |
269 | */ |
270 | |
d34decd2 |
271 | mp *mp_dest(mp *m, size_t sz, unsigned f) |
272 | { |
273 | /* --- If no destination, make one --- */ |
274 | |
275 | if (m == MP_NEWSEC) |
276 | m = mp_new(sz, f | MP_UNDEF | MP_BURN); |
277 | else if (m == MP_NEW) |
278 | m = mp_new(sz, f | MP_UNDEF); |
279 | else { |
280 | size_t len = MP_LEN(m); |
281 | unsigned undef = (m->f | f) & MP_UNDEF; |
282 | |
283 | /* --- If the value must be preserved, the block can't shrink --- */ |
284 | |
285 | if (!undef && sz < len) |
286 | sz = len; |
287 | |
288 | /* --- Otherwise check whether the destination is suitable --- */ |
289 | |
290 | if (m->ref > 1 || (m->f & MP_CONST) || |
291 | m->sz > len || !((f & ~m->f) & MP_BURN)) { |
292 | |
293 | /* --- No -- allocate a new buffer --- * |
294 | * |
295 | * The buffer must be secure if (a) the caller requested a secure |
296 | * buffer, or (b) the old buffer is secure and I'm not allowed to |
297 | * discard the old contents. |
298 | */ |
299 | |
300 | mparena *a; |
301 | mpw *v; |
302 | |
303 | if ((f & MP_BURN) || (!undef && (m->f & MP_BURN))) |
304 | a = MPARENA_SECURE; |
305 | else |
306 | a = MPARENA_GLOBAL; |
307 | v = mpalloc(a, sz); |
308 | |
309 | /* --- Copy the data over --- */ |
310 | |
311 | if (!undef) { |
312 | memcpy(v, m->v, MPWS(len)); |
313 | if (sz - len > 0) |
314 | memset(v + len, 0, MPWS(sz - len)); |
315 | } |
316 | |
317 | /* --- If @m@ has other references, make a new node --- * |
318 | * |
319 | * Otherwise dispose of the old buffer. |
320 | */ |
321 | |
322 | if (!(m->f & MP_CONST) && m->ref == 1) { |
323 | if (m->f & MP_BURN) |
324 | memset(m->v, 0, MPWS(m->sz)); |
325 | mpfree(m->a, m->v); |
326 | } else { |
327 | mp *mm = CREATE(mp); |
328 | mm->ref = 1; |
329 | mm->f = m->f; |
330 | m->ref--; |
331 | m = mm; |
332 | } |
333 | |
334 | /* --- Fix up the node --- */ |
335 | |
336 | m->v = v; |
337 | m->vl = v + sz; |
338 | m->sz = sz; |
339 | m->f = ((m->f & ~(MP_CONST | MP_BURN)) | |
340 | (f & (MP_BURN | MP_UNDEF))); |
341 | m->a = a; |
342 | } |
343 | |
344 | /* --- If the number is growing in its buffer, fix it up --- */ |
345 | |
346 | else if (sz > len) { |
347 | if (!undef) |
348 | memset(m->vl, 0, MPWS(sz - len)); |
349 | m->vl = m->v + sz; |
350 | } |
351 | } |
352 | |
353 | /* --- Done --- */ |
354 | |
355 | return (m); |
356 | } |
d3409d5e |
357 | |
358 | /*----- That's all, folks -------------------------------------------------*/ |