| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: mp-mem.c,v 1.3 2000/06/17 11:45:09 mdw Exp $ |
| 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 $ |
| 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 | * |
| 38 | * Revision 1.2 1999/12/10 23:19:02 mdw |
| 39 | * Improve error-checking. |
| 40 | * |
| 41 | * Revision 1.1 1999/11/17 18:02:16 mdw |
| 42 | * New multiprecision integer arithmetic suite. |
| 43 | * |
| 44 | */ |
| 45 | |
| 46 | /*----- Header files ------------------------------------------------------*/ |
| 47 | |
| 48 | #include <mLib/sub.h> |
| 49 | |
| 50 | |
| 51 | #include "mp.h" |
| 52 | |
| 53 | /*----- Main code ---------------------------------------------------------*/ |
| 54 | |
| 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 | |
| 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); |
| 93 | m->v = mpalloc(MPARENA_GLOBAL, sz); |
| 94 | m->vl = m->v + sz; |
| 95 | m->sz = sz; |
| 96 | m->a = MPARENA_GLOBAL; |
| 97 | m->f = MP_UNDEF; |
| 98 | m->ref = 1; |
| 99 | return (m); |
| 100 | } |
| 101 | |
| 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 | |
| 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 | { |
| 163 | assert(((void)"Destroying a free integer", !(m->f & MP_DESTROYED))); |
| 164 | assert(((void)"Attempted to destroy a constant", !(m->f & MP_CONST))); |
| 165 | if (m->f & MP_BURN) |
| 166 | memset(m->v, 0, MPWS(m->sz)); |
| 167 | mpfree(m->a, m->v); |
| 168 | m->f |= MP_DESTROYED; |
| 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 | |
| 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 | } |
| 219 | |
| 220 | /* --- @mp_resize@ --- * |
| 221 | * |
| 222 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
| 223 | * @size_t sz@ = new size |
| 224 | * |
| 225 | * Returns: --- |
| 226 | * |
| 227 | * Use: Changes an integer's size. The length and value are not |
| 228 | * changed. It is an error to |
| 229 | */ |
| 230 | |
| 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 | } |
| 247 | |
| 248 | /* --- @mp_ensure@ --- * |
| 249 | * |
| 250 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
| 251 | * @size_t sz@ = required length |
| 252 | * |
| 253 | * Returns: --- |
| 254 | * |
| 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 |
| 257 | */ |
| 258 | |
| 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 | } |
| 270 | |
| 271 | /* --- @mp_dest@ --- * |
| 272 | * |
| 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: |
| 282 | * |
| 283 | * * @d@ will have exactly one reference. |
| 284 | * |
| 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. |
| 299 | */ |
| 300 | |
| 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 | } |
| 387 | |
| 388 | /*----- That's all, folks -------------------------------------------------*/ |