Alexandre Lision | 7fd5d3d | 2013-12-04 13:06:40 -0500 | [diff] [blame] | 1 | /* |
| 2 | * bn32.c - the high-level bignum interface |
| 3 | * |
| 4 | * Like lbn32.c, this reserves the string "32" for textual replacement. |
| 5 | * The string must not appear anywhere unless it is intended to be replaced |
| 6 | * to generate other bignum interface functions. |
| 7 | * |
| 8 | * Copyright (c) 1995 Colin Plumb. All rights reserved. |
| 9 | * For licensing and other legal details, see the file legal.c. |
| 10 | */ |
| 11 | |
| 12 | #ifndef HAVE_CONFIG_H |
| 13 | #define HAVE_CONFIG_H 0 |
| 14 | #endif |
| 15 | #if HAVE_CONFIG_H |
Alexandre Lision | 907ed2e | 2014-02-04 10:33:09 -0500 | [diff] [blame] | 16 | #include <bnconfig.h> |
Alexandre Lision | 7fd5d3d | 2013-12-04 13:06:40 -0500 | [diff] [blame] | 17 | #endif |
| 18 | |
| 19 | /* |
| 20 | * Some compilers complain about #if FOO if FOO isn't defined, |
| 21 | * so do the ANSI-mandated thing explicitly... |
| 22 | */ |
| 23 | #ifndef NO_ASSERT_H |
| 24 | #define NO_ASSERT_H 0 |
| 25 | #endif |
| 26 | #ifndef NO_STRING_H |
| 27 | #define NO_STRING_H 0 |
| 28 | #endif |
| 29 | #ifndef HAVE_STRINGS_H |
| 30 | #define HAVE_STRINGS_H 0 |
| 31 | #endif |
| 32 | #ifndef NEED_MEMORY_H |
| 33 | #define NEED_MEMORY_H 0 |
| 34 | #endif |
| 35 | |
| 36 | #if !NO_ASSERT_H |
| 37 | #include <assert.h> |
| 38 | #else |
| 39 | #define assert(x) (void)0 |
| 40 | #endif |
| 41 | |
| 42 | #if !NO_STRING_H |
| 43 | #include <string.h> /* for memmove() in bnMakeOdd */ |
| 44 | #elif HAVE_STRINGS_H |
| 45 | #include <strings.h> |
| 46 | #endif |
| 47 | #if NEED_MEMORY_H |
| 48 | #include <memory.h> |
| 49 | #endif |
| 50 | |
| 51 | /* |
| 52 | * This was useful during debugging, so it's left in here. |
| 53 | * You can ignore it. DBMALLOC is generally undefined. |
| 54 | */ |
| 55 | #ifndef DBMALLOC |
| 56 | #define DBMALLOC 0 |
| 57 | #endif |
| 58 | #if DBMALLOC |
| 59 | #include "../dbmalloc/malloc.h" |
| 60 | #define MALLOCDB malloc_chain_check(1) |
| 61 | #else |
| 62 | #define MALLOCDB (void)0 |
| 63 | #endif |
| 64 | |
| 65 | #include "lbn.h" |
| 66 | #include "lbn32.h" |
| 67 | #include "lbnmem.h" |
| 68 | #include "bn32.h" |
| 69 | #include "bn.h" |
| 70 | |
| 71 | /* Work-arounds for some particularly broken systems */ |
| 72 | #include "kludge.h" /* For memmove() */ |
| 73 | |
| 74 | /* Functions */ |
| 75 | void |
| 76 | bnInit_32(void) |
| 77 | { |
| 78 | bnEnd = bnEnd_32; |
| 79 | bnPrealloc = bnPrealloc_32; |
| 80 | bnCopy = bnCopy_32; |
| 81 | bnNorm = bnNorm_32; |
| 82 | bnExtractBigBytes = bnExtractBigBytes_32; |
| 83 | bnInsertBigBytes = bnInsertBigBytes_32; |
| 84 | bnExtractLittleBytes = bnExtractLittleBytes_32; |
| 85 | bnInsertLittleBytes = bnInsertLittleBytes_32; |
| 86 | bnLSWord = bnLSWord_32; |
| 87 | bnReadBit = bnReadBit_32; |
| 88 | bnBits = bnBits_32; |
| 89 | bnAdd = bnAdd_32; |
| 90 | bnSub = bnSub_32; |
| 91 | bnCmpQ = bnCmpQ_32; |
| 92 | bnSetQ = bnSetQ_32; |
| 93 | bnAddQ = bnAddQ_32; |
| 94 | bnSubQ = bnSubQ_32; |
| 95 | bnCmp = bnCmp_32; |
| 96 | bnSquare = bnSquare_32; |
| 97 | bnMul = bnMul_32; |
| 98 | bnMulQ = bnMulQ_32; |
| 99 | bnDivMod = bnDivMod_32; |
| 100 | bnMod = bnMod_32; |
| 101 | bnModQ = bnModQ_32; |
| 102 | bnExpMod = bnExpMod_32; |
| 103 | bnDoubleExpMod = bnDoubleExpMod_32; |
| 104 | bnTwoExpMod = bnTwoExpMod_32; |
| 105 | bnGcd = bnGcd_32; |
| 106 | bnInv = bnInv_32; |
| 107 | bnLShift = bnLShift_32; |
| 108 | bnRShift = bnRShift_32; |
| 109 | bnMakeOdd = bnMakeOdd_32; |
| 110 | bnBasePrecompBegin = bnBasePrecompBegin_32; |
| 111 | bnBasePrecompEnd = bnBasePrecompEnd_32; |
| 112 | bnBasePrecompExpMod = bnBasePrecompExpMod_32; |
| 113 | bnDoubleBasePrecompExpMod = bnDoubleBasePrecompExpMod_32; |
| 114 | } |
| 115 | |
| 116 | void |
| 117 | bnEnd_32(struct BigNum *bn) |
| 118 | { |
| 119 | if (bn->ptr) { |
| 120 | LBNFREE((BNWORD32 *)bn->ptr, bn->allocated); |
| 121 | bn->ptr = 0; |
| 122 | } |
| 123 | bn->size = 0; |
| 124 | bn->allocated = 0; |
| 125 | |
| 126 | MALLOCDB; |
| 127 | } |
| 128 | |
| 129 | /* Internal function. It operates in words. */ |
| 130 | static int |
| 131 | bnResize_32(struct BigNum *bn, unsigned len) |
| 132 | { |
| 133 | void *p; |
| 134 | |
| 135 | /* Round size up: most mallocs impose 8-byte granularity anyway */ |
| 136 | len = (len + (8/sizeof(BNWORD32) - 1)) & ~(8/sizeof(BNWORD32) - 1); |
| 137 | p = LBNREALLOC((BNWORD32 *)bn->ptr, bn->allocated, len); |
| 138 | if (!p) |
| 139 | return -1; |
| 140 | bn->ptr = p; |
| 141 | bn->allocated = len; |
| 142 | |
| 143 | MALLOCDB; |
| 144 | |
| 145 | return 0; |
| 146 | } |
| 147 | |
| 148 | #define bnSizeCheck(bn, size) \ |
| 149 | if (bn->allocated < size && bnResize_32(bn, size) < 0) \ |
| 150 | return -1 |
| 151 | |
| 152 | /* Preallocate enough space in bn to hold "bits" bits. */ |
| 153 | int |
| 154 | bnPrealloc_32(struct BigNum *bn, unsigned bits) |
| 155 | { |
| 156 | bits = (bits + 32-1)/32; |
| 157 | bnSizeCheck(bn, bits); |
| 158 | MALLOCDB; |
| 159 | return 0; |
| 160 | } |
| 161 | |
| 162 | int |
| 163 | bnCopy_32(struct BigNum *dest, struct BigNum const *src) |
| 164 | { |
| 165 | bnSizeCheck(dest, src->size); |
| 166 | dest->size = src->size; |
| 167 | lbnCopy_32((BNWORD32 *)dest->ptr, (BNWORD32 *)src->ptr, src->size); |
| 168 | MALLOCDB; |
| 169 | return 0; |
| 170 | } |
| 171 | |
| 172 | /* Is this ever needed? Normalize the bn by deleting high-order 0 words */ |
| 173 | void |
| 174 | bnNorm_32(struct BigNum *bn) |
| 175 | { |
| 176 | bn->size = lbnNorm_32((BNWORD32 *)bn->ptr, bn->size); |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | * Convert a bignum to big-endian bytes. Returns, in big-endian form, a |
| 181 | * substring of the bignum starting from lsbyte and "len" bytes long. |
| 182 | * Unused high-order (leading) bytes are filled with 0. |
| 183 | */ |
| 184 | void |
| 185 | bnExtractBigBytes_32(struct BigNum const *bn, unsigned char *dest, |
| 186 | unsigned lsbyte, unsigned len) |
| 187 | { |
| 188 | unsigned s = bn->size * (32 / 8); |
| 189 | |
| 190 | /* Fill unused leading bytes with 0 */ |
| 191 | while (s < lsbyte + len) { |
| 192 | *dest++ = 0; |
| 193 | len--; |
| 194 | } |
| 195 | |
| 196 | if (len) |
| 197 | lbnExtractBigBytes_32((BNWORD32 *)bn->ptr, dest, lsbyte, len); |
| 198 | MALLOCDB; |
| 199 | } |
| 200 | |
| 201 | /* The inverse of the above. */ |
| 202 | int |
| 203 | bnInsertBigBytes_32(struct BigNum *bn, unsigned char const *src, |
| 204 | unsigned lsbyte, unsigned len) |
| 205 | { |
| 206 | unsigned s = bn->size; |
| 207 | unsigned words = (len+lsbyte+sizeof(BNWORD32)-1) / sizeof(BNWORD32); |
| 208 | |
| 209 | /* Pad with zeros as required */ |
| 210 | bnSizeCheck(bn, words); |
| 211 | |
| 212 | if (s < words) { |
| 213 | lbnZero_32((BNWORD32 *)bn->ptr BIGLITTLE(-s,+s), words-s); |
| 214 | s = words; |
| 215 | } |
| 216 | |
| 217 | lbnInsertBigBytes_32((BNWORD32 *)bn->ptr, src, lsbyte, len); |
| 218 | |
| 219 | bn->size = lbnNorm_32((BNWORD32 *)bn->ptr, s); |
| 220 | |
| 221 | MALLOCDB; |
| 222 | return 0; |
| 223 | } |
| 224 | |
| 225 | |
| 226 | /* |
| 227 | * Convert a bignum to little-endian bytes. Returns, in little-endian form, a |
| 228 | * substring of the bignum starting from lsbyte and "len" bytes long. |
| 229 | * Unused high-order (trailing) bytes are filled with 0. |
| 230 | */ |
| 231 | void |
| 232 | bnExtractLittleBytes_32(struct BigNum const *bn, unsigned char *dest, |
| 233 | unsigned lsbyte, unsigned len) |
| 234 | { |
| 235 | unsigned s = bn->size * (32 / 8); |
| 236 | |
| 237 | /* Fill unused leading bytes with 0 */ |
| 238 | while (s < lsbyte + len) |
| 239 | dest[--len] = 0; |
| 240 | |
| 241 | if (len) |
| 242 | lbnExtractLittleBytes_32((BNWORD32 *)bn->ptr, dest, |
| 243 | lsbyte, len); |
| 244 | MALLOCDB; |
| 245 | } |
| 246 | |
| 247 | /* The inverse of the above */ |
| 248 | int |
| 249 | bnInsertLittleBytes_32(struct BigNum *bn, unsigned char const *src, |
| 250 | unsigned lsbyte, unsigned len) |
| 251 | { |
| 252 | unsigned s = bn->size; |
| 253 | unsigned words = (len+lsbyte+sizeof(BNWORD32)-1) / sizeof(BNWORD32); |
| 254 | |
| 255 | /* Pad with zeros as required */ |
| 256 | bnSizeCheck(bn, words); |
| 257 | |
| 258 | if (s < words) { |
| 259 | lbnZero_32((BNWORD32 *)bn->ptr BIGLITTLE(-s,+s), words-s); |
| 260 | s = words; |
| 261 | } |
| 262 | |
| 263 | lbnInsertLittleBytes_32((BNWORD32 *)bn->ptr, src, lsbyte, len); |
| 264 | |
| 265 | bn->size = lbnNorm_32((BNWORD32 *)bn->ptr, s); |
| 266 | |
| 267 | MALLOCDB; |
| 268 | return 0; |
| 269 | } |
| 270 | |
| 271 | /* Return the least-significant word of the input. */ |
| 272 | unsigned |
| 273 | bnLSWord_32(struct BigNum const *bn) |
| 274 | { |
| 275 | return bn->size ? (unsigned)((BNWORD32 *)bn->ptr)[BIGLITTLE(-1,0)]: 0; |
| 276 | } |
| 277 | |
| 278 | /* Return a selected bit of the data */ |
| 279 | int |
| 280 | bnReadBit_32(struct BigNum const *bn, unsigned bit) |
| 281 | { |
| 282 | BNWORD32 word; |
| 283 | if (bit/32 >= bn->size) |
| 284 | return 0; |
| 285 | word = ((BNWORD32 *)bn->ptr)[BIGLITTLE(-1-bit/32,bit/32)]; |
| 286 | return (int)(word >> (bit % 32) & 1); |
| 287 | } |
| 288 | |
| 289 | /* Count the number of significant bits. */ |
| 290 | unsigned |
| 291 | bnBits_32(struct BigNum const *bn) |
| 292 | { |
| 293 | return lbnBits_32((BNWORD32 *)bn->ptr, bn->size); |
| 294 | } |
| 295 | |
| 296 | /* dest += src */ |
| 297 | int |
| 298 | bnAdd_32(struct BigNum *dest, struct BigNum const *src) |
| 299 | { |
| 300 | unsigned s = src->size, d = dest->size; |
| 301 | BNWORD32 t; |
| 302 | |
| 303 | if (!s) |
| 304 | return 0; |
| 305 | |
| 306 | bnSizeCheck(dest, s); |
| 307 | |
| 308 | if (d < s) { |
| 309 | lbnZero_32((BNWORD32 *)dest->ptr BIGLITTLE(-d,+d), s-d); |
| 310 | dest->size = d = s; |
| 311 | MALLOCDB; |
| 312 | } |
| 313 | t = lbnAddN_32((BNWORD32 *)dest->ptr, (BNWORD32 *)src->ptr, s); |
| 314 | MALLOCDB; |
| 315 | if (t) { |
| 316 | if (d > s) { |
| 317 | t = lbnAdd1_32((BNWORD32 *)dest->ptr BIGLITTLE(-s,+s), |
| 318 | d-s, t); |
| 319 | MALLOCDB; |
| 320 | } |
| 321 | if (t) { |
| 322 | bnSizeCheck(dest, d+1); |
| 323 | ((BNWORD32 *)dest->ptr)[BIGLITTLE(-1-d,d)] = t; |
| 324 | dest->size = d+1; |
| 325 | } |
| 326 | } |
| 327 | return 0; |
| 328 | } |
| 329 | |
| 330 | /* |
| 331 | * dest -= src. |
| 332 | * If dest goes negative, this produces the absolute value of |
| 333 | * the difference (the negative of the true value) and returns 1. |
| 334 | * Otherwise, it returls 0. |
| 335 | */ |
| 336 | int |
| 337 | bnSub_32(struct BigNum *dest, struct BigNum const *src) |
| 338 | { |
| 339 | unsigned s = src->size, d = dest->size; |
| 340 | BNWORD32 t; |
| 341 | |
| 342 | if (d < s && d < (s = lbnNorm_32((BNWORD32 *)src->ptr, s))) { |
| 343 | bnSizeCheck(dest, s); |
| 344 | lbnZero_32((BNWORD32 *)dest->ptr BIGLITTLE(-d,+d), s-d); |
| 345 | dest->size = d = s; |
| 346 | MALLOCDB; |
| 347 | } |
| 348 | if (!s) |
| 349 | return 0; |
| 350 | t = lbnSubN_32((BNWORD32 *)dest->ptr, (BNWORD32 *)src->ptr, s); |
| 351 | MALLOCDB; |
| 352 | if (t) { |
| 353 | if (d > s) { |
| 354 | t = lbnSub1_32((BNWORD32 *)dest->ptr BIGLITTLE(-s,+s), |
| 355 | d-s, t); |
| 356 | MALLOCDB; |
| 357 | } |
| 358 | if (t) { |
| 359 | lbnNeg_32((BNWORD32 *)dest->ptr, d); |
| 360 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, |
| 361 | dest->size); |
| 362 | MALLOCDB; |
| 363 | return 1; |
| 364 | } |
| 365 | } |
| 366 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, dest->size); |
| 367 | return 0; |
| 368 | } |
| 369 | |
| 370 | /* |
| 371 | * Compare the BigNum to the given value, which must be < 65536. |
| 372 | * Returns -1. 0 or 1 if a<b, a == b or a>b. |
| 373 | * a <=> b --> bnCmpQ(a,b) <=> 0 |
| 374 | */ |
| 375 | int |
| 376 | bnCmpQ_32(struct BigNum const *a, unsigned b) |
| 377 | { |
| 378 | unsigned t; |
| 379 | BNWORD32 v; |
| 380 | |
| 381 | t = lbnNorm_32((BNWORD32 *)a->ptr, a->size); |
| 382 | /* If a is more than one word long or zero, it's easy... */ |
| 383 | if (t != 1) |
| 384 | return (t > 1) ? 1 : (b ? -1 : 0); |
| 385 | v = (unsigned)((BNWORD32 *)a->ptr)[BIGLITTLE(-1,0)]; |
| 386 | return (v > b) ? 1 : ((v < b) ? -1 : 0); |
| 387 | } |
| 388 | |
| 389 | /* Set dest to a small value */ |
| 390 | int |
| 391 | bnSetQ_32(struct BigNum *dest, unsigned src) |
| 392 | { |
| 393 | if (src) { |
| 394 | bnSizeCheck(dest, 1); |
| 395 | |
| 396 | ((BNWORD32 *)dest->ptr)[BIGLITTLE(-1,0)] = (BNWORD32)src; |
| 397 | dest->size = 1; |
| 398 | } else { |
| 399 | dest->size = 0; |
| 400 | } |
| 401 | return 0; |
| 402 | } |
| 403 | |
| 404 | /* dest += src */ |
| 405 | int |
| 406 | bnAddQ_32(struct BigNum *dest, unsigned src) |
| 407 | { |
| 408 | BNWORD32 t; |
| 409 | |
| 410 | if (!dest->size) |
| 411 | return bnSetQ(dest, src); |
| 412 | |
| 413 | t = lbnAdd1_32((BNWORD32 *)dest->ptr, dest->size, (BNWORD32)src); |
| 414 | MALLOCDB; |
| 415 | if (t) { |
| 416 | src = dest->size; |
| 417 | bnSizeCheck(dest, src+1); |
| 418 | ((BNWORD32 *)dest->ptr)[BIGLITTLE(-1-src,src)] = t; |
| 419 | dest->size = src+1; |
| 420 | } |
| 421 | return 0; |
| 422 | } |
| 423 | |
| 424 | /* |
| 425 | * Return value as for bnSub: 1 if subtract underflowed, in which |
| 426 | * case the return is the negative of the computed value. |
| 427 | */ |
| 428 | int |
| 429 | bnSubQ_32(struct BigNum *dest, unsigned src) |
| 430 | { |
| 431 | BNWORD32 t; |
| 432 | |
| 433 | if (!dest->size) |
| 434 | return bnSetQ(dest, src) < 0 ? -1 : (src != 0); |
| 435 | |
| 436 | t = lbnSub1_32((BNWORD32 *)dest->ptr, dest->size, src); |
| 437 | MALLOCDB; |
| 438 | if (t) { |
| 439 | /* Underflow. <= 1 word, so do it simply. */ |
| 440 | lbnNeg_32((BNWORD32 *)dest->ptr, 1); |
| 441 | dest->size = 1; |
| 442 | return 1; |
| 443 | } |
| 444 | /* Try to normalize? Needing this is going to be pretty damn rare. */ |
| 445 | /* dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, dest->size); */ |
| 446 | return 0; |
| 447 | } |
| 448 | |
| 449 | /* |
| 450 | * Compare two BigNums. Returns -1. 0 or 1 if a<b, a == b or a>b. |
| 451 | * a <=> b --> bnCmp(a,b) <=> 0 |
| 452 | */ |
| 453 | int |
| 454 | bnCmp_32(struct BigNum const *a, struct BigNum const *b) |
| 455 | { |
| 456 | unsigned s, t; |
| 457 | |
| 458 | s = lbnNorm_32((BNWORD32 *)a->ptr, a->size); |
| 459 | t = lbnNorm_32((BNWORD32 *)b->ptr, b->size); |
| 460 | |
| 461 | if (s != t) |
| 462 | return s > t ? 1 : -1; |
| 463 | return lbnCmp_32((BNWORD32 *)a->ptr, (BNWORD32 *)b->ptr, s); |
| 464 | } |
| 465 | |
| 466 | /* dest = src*src. This is more efficient than bnMul. */ |
| 467 | int |
| 468 | bnSquare_32(struct BigNum *dest, struct BigNum const *src) |
| 469 | { |
| 470 | unsigned s; |
| 471 | BNWORD32 *srcbuf; |
| 472 | |
| 473 | s = lbnNorm_32((BNWORD32 *)src->ptr, src->size); |
| 474 | if (!s) { |
| 475 | dest->size = 0; |
| 476 | return 0; |
| 477 | } |
| 478 | bnSizeCheck(dest, 2*s); |
| 479 | |
| 480 | if (src == dest) { |
| 481 | LBNALLOC(srcbuf, BNWORD32, s); |
| 482 | if (!srcbuf) |
| 483 | return -1; |
| 484 | lbnCopy_32(srcbuf, (BNWORD32 *)src->ptr, s); |
| 485 | lbnSquare_32((BNWORD32 *)dest->ptr, (BNWORD32 *)srcbuf, s); |
| 486 | LBNFREE(srcbuf, s); |
| 487 | } else { |
| 488 | lbnSquare_32((BNWORD32 *)dest->ptr, (BNWORD32 *)src->ptr, s); |
| 489 | } |
| 490 | |
| 491 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, 2*s); |
| 492 | MALLOCDB; |
| 493 | return 0; |
| 494 | } |
| 495 | |
| 496 | /* dest = a * b. Any overlap between operands is allowed. */ |
| 497 | int |
| 498 | bnMul_32(struct BigNum *dest, struct BigNum const *a, struct BigNum const *b) |
| 499 | { |
| 500 | unsigned s, t; |
| 501 | BNWORD32 *srcbuf; |
| 502 | |
| 503 | s = lbnNorm_32((BNWORD32 *)a->ptr, a->size); |
| 504 | t = lbnNorm_32((BNWORD32 *)b->ptr, b->size); |
| 505 | |
| 506 | if (!s || !t) { |
| 507 | dest->size = 0; |
| 508 | return 0; |
| 509 | } |
| 510 | |
| 511 | if (a == b) |
| 512 | return bnSquare_32(dest, a); |
| 513 | |
| 514 | bnSizeCheck(dest, s+t); |
| 515 | |
| 516 | if (dest == a) { |
| 517 | LBNALLOC(srcbuf, BNWORD32, s); |
| 518 | if (!srcbuf) |
| 519 | return -1; |
| 520 | lbnCopy_32(srcbuf, (BNWORD32 *)a->ptr, s); |
| 521 | lbnMul_32((BNWORD32 *)dest->ptr, srcbuf, s, |
| 522 | (BNWORD32 *)b->ptr, t); |
| 523 | LBNFREE(srcbuf, s); |
| 524 | } else if (dest == b) { |
| 525 | LBNALLOC(srcbuf, BNWORD32, t); |
| 526 | if (!srcbuf) |
| 527 | return -1; |
| 528 | lbnCopy_32(srcbuf, (BNWORD32 *)b->ptr, t); |
| 529 | lbnMul_32((BNWORD32 *)dest->ptr, (BNWORD32 *)a->ptr, s, |
| 530 | srcbuf, t); |
| 531 | LBNFREE(srcbuf, t); |
| 532 | } else { |
| 533 | lbnMul_32((BNWORD32 *)dest->ptr, (BNWORD32 *)a->ptr, s, |
| 534 | (BNWORD32 *)b->ptr, t); |
| 535 | } |
| 536 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, s+t); |
| 537 | MALLOCDB; |
| 538 | return 0; |
| 539 | } |
| 540 | |
| 541 | /* dest = a * b */ |
| 542 | int |
| 543 | bnMulQ_32(struct BigNum *dest, struct BigNum const *a, unsigned b) |
| 544 | { |
| 545 | unsigned s; |
| 546 | |
| 547 | s = lbnNorm_32((BNWORD32 *)a->ptr, a->size); |
| 548 | if (!s || !b) { |
| 549 | dest->size = 0; |
| 550 | return 0; |
| 551 | } |
| 552 | if (b == 1) |
| 553 | return bnCopy_32(dest, a); |
| 554 | bnSizeCheck(dest, s+1); |
| 555 | lbnMulN1_32((BNWORD32 *)dest->ptr, (BNWORD32 *)a->ptr, s, b); |
| 556 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, s+1); |
| 557 | MALLOCDB; |
| 558 | return 0; |
| 559 | } |
| 560 | |
| 561 | /* q = n/d, r = n % d */ |
| 562 | int |
| 563 | bnDivMod_32(struct BigNum *q, struct BigNum *r, struct BigNum const *n, |
| 564 | struct BigNum const *d) |
| 565 | { |
| 566 | unsigned dsize, nsize; |
| 567 | BNWORD32 qhigh; |
| 568 | |
| 569 | dsize = lbnNorm_32((BNWORD32 *)d->ptr, d->size); |
| 570 | nsize = lbnNorm_32((BNWORD32 *)n->ptr, n->size); |
| 571 | |
| 572 | if (nsize < dsize) { |
| 573 | q->size = 0; /* No quotient */ |
| 574 | r->size = nsize; |
| 575 | return 0; /* Success */ |
| 576 | } |
| 577 | |
| 578 | bnSizeCheck(q, nsize-dsize); |
| 579 | |
| 580 | if (r != n) { /* You are allowed to reduce in place */ |
| 581 | bnSizeCheck(r, nsize); |
| 582 | lbnCopy_32((BNWORD32 *)r->ptr, (BNWORD32 *)n->ptr, nsize); |
| 583 | } |
| 584 | |
| 585 | qhigh = lbnDiv_32((BNWORD32 *)q->ptr, (BNWORD32 *)r->ptr, nsize, |
| 586 | (BNWORD32 *)d->ptr, dsize); |
| 587 | nsize -= dsize; |
| 588 | if (qhigh) { |
| 589 | bnSizeCheck(q, nsize+1); |
| 590 | *((BNWORD32 *)q->ptr BIGLITTLE(-nsize-1,+nsize)) = qhigh; |
| 591 | q->size = nsize+1; |
| 592 | } else { |
| 593 | q->size = lbnNorm_32((BNWORD32 *)q->ptr, nsize); |
| 594 | } |
| 595 | r->size = lbnNorm_32((BNWORD32 *)r->ptr, dsize); |
| 596 | MALLOCDB; |
| 597 | return 0; |
| 598 | } |
| 599 | |
| 600 | /* det = src % d */ |
| 601 | int |
| 602 | bnMod_32(struct BigNum *dest, struct BigNum const *src, struct BigNum const *d) |
| 603 | { |
| 604 | unsigned dsize, nsize; |
| 605 | |
| 606 | nsize = lbnNorm_32((BNWORD32 *)src->ptr, src->size); |
| 607 | dsize = lbnNorm_32((BNWORD32 *)d->ptr, d->size); |
| 608 | |
| 609 | |
| 610 | if (dest != src) { |
| 611 | bnSizeCheck(dest, nsize); |
| 612 | lbnCopy_32((BNWORD32 *)dest->ptr, (BNWORD32 *)src->ptr, nsize); |
| 613 | } |
| 614 | |
| 615 | if (nsize < dsize) { |
| 616 | dest->size = nsize; /* No quotient */ |
| 617 | return 0; |
| 618 | } |
| 619 | |
| 620 | (void)lbnDiv_32((BNWORD32 *)dest->ptr BIGLITTLE(-dsize,+dsize), |
| 621 | (BNWORD32 *)dest->ptr, nsize, |
| 622 | (BNWORD32 *)d->ptr, dsize); |
| 623 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, dsize); |
| 624 | MALLOCDB; |
| 625 | return 0; |
| 626 | } |
| 627 | |
| 628 | /* return src % d. */ |
| 629 | unsigned |
| 630 | bnModQ_32(struct BigNum const *src, unsigned d) |
| 631 | { |
| 632 | unsigned s; |
| 633 | |
| 634 | s = lbnNorm_32((BNWORD32 *)src->ptr, src->size); |
| 635 | if (!s) |
| 636 | return 0; |
| 637 | |
| 638 | if (d & (d-1)) /* Not a power of 2 */ |
| 639 | d = lbnModQ_32((BNWORD32 *)src->ptr, s, d); |
| 640 | else |
| 641 | d = (unsigned)((BNWORD32 *)src->ptr)[BIGLITTLE(-1,0)] & (d-1); |
| 642 | return d; |
| 643 | } |
| 644 | |
| 645 | /* dest = n^exp (mod mod) */ |
| 646 | int |
| 647 | bnExpMod_32(struct BigNum *dest, struct BigNum const *n, |
| 648 | struct BigNum const *exp, struct BigNum const *mod) |
| 649 | { |
| 650 | unsigned nsize, esize, msize; |
| 651 | |
| 652 | nsize = lbnNorm_32((BNWORD32 *)n->ptr, n->size); |
| 653 | esize = lbnNorm_32((BNWORD32 *)exp->ptr, exp->size); |
| 654 | msize = lbnNorm_32((BNWORD32 *)mod->ptr, mod->size); |
| 655 | |
| 656 | if (!msize || (((BNWORD32 *)mod->ptr)[BIGLITTLE(-1,0)] & 1) == 0) |
| 657 | return -1; /* Illegal modulus! */ |
| 658 | |
| 659 | bnSizeCheck(dest, msize); |
| 660 | |
| 661 | /* Special-case base of 2 */ |
| 662 | if (nsize == 1 && ((BNWORD32 *)n->ptr)[BIGLITTLE(-1,0)] == 2) { |
| 663 | if (lbnTwoExpMod_32((BNWORD32 *)dest->ptr, |
| 664 | (BNWORD32 *)exp->ptr, esize, |
| 665 | (BNWORD32 *)mod->ptr, msize) < 0) |
| 666 | return -1; |
| 667 | } else { |
| 668 | if (lbnExpMod_32((BNWORD32 *)dest->ptr, |
| 669 | (BNWORD32 *)n->ptr, nsize, |
| 670 | (BNWORD32 *)exp->ptr, esize, |
| 671 | (BNWORD32 *)mod->ptr, msize) < 0) |
| 672 | return -1; |
| 673 | } |
| 674 | |
| 675 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, msize); |
| 676 | MALLOCDB; |
| 677 | return 0; |
| 678 | } |
| 679 | |
| 680 | /* |
| 681 | * dest = n1^e1 * n2^e2 (mod mod). This is more efficient than two |
| 682 | * separate modular exponentiations, and in fact asymptotically approaches |
| 683 | * the cost of one. |
| 684 | */ |
| 685 | int |
| 686 | bnDoubleExpMod_32(struct BigNum *dest, |
| 687 | struct BigNum const *n1, struct BigNum const *e1, |
| 688 | struct BigNum const *n2, struct BigNum const *e2, |
| 689 | struct BigNum const *mod) |
| 690 | { |
| 691 | unsigned n1size, e1size, n2size, e2size, msize; |
| 692 | |
| 693 | n1size = lbnNorm_32((BNWORD32 *)n1->ptr, n1->size); |
| 694 | e1size = lbnNorm_32((BNWORD32 *)e1->ptr, e1->size); |
| 695 | n2size = lbnNorm_32((BNWORD32 *)n2->ptr, n2->size); |
| 696 | e2size = lbnNorm_32((BNWORD32 *)e2->ptr, e2->size); |
| 697 | msize = lbnNorm_32((BNWORD32 *)mod->ptr, mod->size); |
| 698 | |
| 699 | if (!msize || (((BNWORD32 *)mod->ptr)[BIGLITTLE(-1,0)] & 1) == 0) |
| 700 | return -1; /* Illegal modulus! */ |
| 701 | |
| 702 | bnSizeCheck(dest, msize); |
| 703 | |
| 704 | if (lbnDoubleExpMod_32((BNWORD32 *)dest->ptr, |
| 705 | (BNWORD32 *)n1->ptr, n1size, (BNWORD32 *)e1->ptr, e1size, |
| 706 | (BNWORD32 *)n2->ptr, n2size, (BNWORD32 *)e2->ptr, e2size, |
| 707 | (BNWORD32 *)mod->ptr, msize) < 0) |
| 708 | return -1; |
| 709 | |
| 710 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, msize); |
| 711 | MALLOCDB; |
| 712 | return 0; |
| 713 | } |
| 714 | |
| 715 | /* n = 2^exp (mod mod) */ |
| 716 | int |
| 717 | bnTwoExpMod_32(struct BigNum *n, struct BigNum const *exp, |
| 718 | struct BigNum const *mod) |
| 719 | { |
| 720 | unsigned esize, msize; |
| 721 | |
| 722 | esize = lbnNorm_32((BNWORD32 *)exp->ptr, exp->size); |
| 723 | msize = lbnNorm_32((BNWORD32 *)mod->ptr, mod->size); |
| 724 | |
| 725 | if (!msize || (((BNWORD32 *)mod->ptr)[BIGLITTLE(-1,0)] & 1) == 0) |
| 726 | return -1; /* Illegal modulus! */ |
| 727 | |
| 728 | bnSizeCheck(n, msize); |
| 729 | |
| 730 | if (lbnTwoExpMod_32((BNWORD32 *)n->ptr, (BNWORD32 *)exp->ptr, esize, |
| 731 | (BNWORD32 *)mod->ptr, msize) < 0) |
| 732 | return -1; |
| 733 | |
| 734 | n->size = lbnNorm_32((BNWORD32 *)n->ptr, msize); |
| 735 | MALLOCDB; |
| 736 | return 0; |
| 737 | } |
| 738 | |
| 739 | /* dest = gcd(a, b) */ |
| 740 | int |
| 741 | bnGcd_32(struct BigNum *dest, struct BigNum const *a, struct BigNum const *b) |
| 742 | { |
| 743 | BNWORD32 *tmp; |
| 744 | unsigned asize, bsize; |
| 745 | int i; |
| 746 | |
| 747 | /* Kind of silly, but we might as well permit it... */ |
| 748 | if (a == b) |
| 749 | return dest == a ? 0 : bnCopy(dest, a); |
| 750 | |
| 751 | /* Ensure a is not the same as "dest" */ |
| 752 | if (a == dest) { |
| 753 | a = b; |
| 754 | b = dest; |
| 755 | } |
| 756 | |
| 757 | asize = lbnNorm_32((BNWORD32 *)a->ptr, a->size); |
| 758 | bsize = lbnNorm_32((BNWORD32 *)b->ptr, b->size); |
| 759 | |
| 760 | bnSizeCheck(dest, bsize+1); |
| 761 | |
| 762 | /* Copy a to tmp */ |
| 763 | LBNALLOC(tmp, BNWORD32, asize+1); |
| 764 | if (!tmp) |
| 765 | return -1; |
| 766 | lbnCopy_32(tmp, (BNWORD32 *)a->ptr, asize); |
| 767 | |
| 768 | /* Copy b to dest, if necessary */ |
| 769 | if (dest != b) |
| 770 | lbnCopy_32((BNWORD32 *)dest->ptr, |
| 771 | (BNWORD32 *)b->ptr, bsize); |
| 772 | if (bsize > asize || (bsize == asize && |
| 773 | lbnCmp_32((BNWORD32 *)b->ptr, (BNWORD32 *)a->ptr, asize) > 0)) |
| 774 | { |
| 775 | i = lbnGcd_32((BNWORD32 *)dest->ptr, bsize, tmp, asize, |
| 776 | &dest->size); |
| 777 | if (i > 0) /* Result in tmp, not dest */ |
| 778 | lbnCopy_32((BNWORD32 *)dest->ptr, tmp, dest->size); |
| 779 | } else { |
| 780 | i = lbnGcd_32(tmp, asize, (BNWORD32 *)dest->ptr, bsize, |
| 781 | &dest->size); |
| 782 | if (i == 0) /* Result in tmp, not dest */ |
| 783 | lbnCopy_32((BNWORD32 *)dest->ptr, tmp, dest->size); |
| 784 | } |
| 785 | LBNFREE(tmp, asize+1); |
| 786 | MALLOCDB; |
| 787 | return (i < 0) ? i : 0; |
| 788 | } |
| 789 | |
| 790 | /* |
| 791 | * dest = 1/src (mod mod). Returns >0 if gcd(src, mod) != 1 (in which case |
| 792 | * the inverse does not exist). |
| 793 | */ |
| 794 | int |
| 795 | bnInv_32(struct BigNum *dest, struct BigNum const *src, |
| 796 | struct BigNum const *mod) |
| 797 | { |
| 798 | unsigned s, m; |
| 799 | int i; |
| 800 | |
| 801 | s = lbnNorm_32((BNWORD32 *)src->ptr, src->size); |
| 802 | m = lbnNorm_32((BNWORD32 *)mod->ptr, mod->size); |
| 803 | |
| 804 | /* lbnInv_32 requires that the input be less than the modulus */ |
| 805 | if (m < s || |
| 806 | (m==s && lbnCmp_32((BNWORD32 *)src->ptr, (BNWORD32 *)mod->ptr, s))) |
| 807 | { |
| 808 | bnSizeCheck(dest, s + (m==s)); |
| 809 | if (dest != src) |
| 810 | lbnCopy_32((BNWORD32 *)dest->ptr, |
| 811 | (BNWORD32 *)src->ptr, s); |
| 812 | /* Pre-reduce modulo the modulus */ |
| 813 | (void)lbnDiv_32((BNWORD32 *)dest->ptr BIGLITTLE(-m,+m), |
| 814 | (BNWORD32 *)dest->ptr, s, |
| 815 | (BNWORD32 *)mod->ptr, m); |
| 816 | s = lbnNorm_32((BNWORD32 *)dest->ptr, m); |
| 817 | MALLOCDB; |
| 818 | } else { |
| 819 | bnSizeCheck(dest, m+1); |
| 820 | if (dest != src) |
| 821 | lbnCopy_32((BNWORD32 *)dest->ptr, |
| 822 | (BNWORD32 *)src->ptr, s); |
| 823 | } |
| 824 | |
| 825 | i = lbnInv_32((BNWORD32 *)dest->ptr, s, (BNWORD32 *)mod->ptr, m); |
| 826 | if (i == 0) |
| 827 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, m); |
| 828 | |
| 829 | MALLOCDB; |
| 830 | return i; |
| 831 | } |
| 832 | |
| 833 | /* |
| 834 | * Shift a bignum left the appropriate number of bits, |
| 835 | * multiplying by 2^amt. |
| 836 | */ |
| 837 | int |
| 838 | bnLShift_32(struct BigNum *dest, unsigned amt) |
| 839 | { |
| 840 | unsigned s = dest->size; |
| 841 | BNWORD32 carry; |
| 842 | |
| 843 | if (amt % 32) { |
| 844 | carry = lbnLshift_32((BNWORD32 *)dest->ptr, s, amt % 32); |
| 845 | if (carry) { |
| 846 | s++; |
| 847 | bnSizeCheck(dest, s); |
| 848 | ((BNWORD32 *)dest->ptr)[BIGLITTLE(-s,s-1)] = carry; |
| 849 | } |
| 850 | } |
| 851 | |
| 852 | amt /= 32; |
| 853 | if (amt) { |
| 854 | bnSizeCheck(dest, s+amt); |
| 855 | memmove((BNWORD32 *)dest->ptr BIGLITTLE(-s-amt, +amt), |
| 856 | (BNWORD32 *)dest->ptr BIG(-s), |
| 857 | s * sizeof(BNWORD32)); |
| 858 | lbnZero_32((BNWORD32 *)dest->ptr, amt); |
| 859 | s += amt; |
| 860 | } |
| 861 | dest->size = s; |
| 862 | MALLOCDB; |
| 863 | return 0; |
| 864 | } |
| 865 | |
| 866 | /* |
| 867 | * Shift a bignum right the appropriate number of bits, |
| 868 | * dividing by 2^amt. |
| 869 | */ |
| 870 | void |
| 871 | bnRShift_32(struct BigNum *dest, unsigned amt) |
| 872 | { |
| 873 | unsigned s = dest->size; |
| 874 | |
| 875 | if (amt >= 32) { |
| 876 | memmove( |
| 877 | (BNWORD32 *)dest->ptr BIG(-s+amt/32), |
| 878 | (BNWORD32 *)dest->ptr BIGLITTLE(-s, +amt/32), |
| 879 | (s-amt/32) * sizeof(BNWORD32)); |
| 880 | s -= amt/32; |
| 881 | amt %= 32; |
| 882 | } |
| 883 | |
| 884 | if (amt) |
| 885 | (void)lbnRshift_32((BNWORD32 *)dest->ptr, s, amt); |
| 886 | |
| 887 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, s); |
| 888 | MALLOCDB; |
| 889 | } |
| 890 | |
| 891 | /* |
| 892 | * Shift a bignum right until it is odd, and return the number of |
| 893 | * bits shifted. n = d * 2^s. Replaces n with d and returns s. |
| 894 | * Returns 0 when given 0. (Another valid answer is infinity.) |
| 895 | */ |
| 896 | unsigned |
| 897 | bnMakeOdd_32(struct BigNum *n) |
| 898 | { |
| 899 | unsigned size; |
| 900 | unsigned s; /* shift amount */ |
| 901 | BNWORD32 *p; |
| 902 | BNWORD32 t; |
| 903 | |
| 904 | p = (BNWORD32 *)n->ptr; |
| 905 | size = lbnNorm_32(p, n->size); |
| 906 | if (!size) |
| 907 | return 0; |
| 908 | |
| 909 | t = BIGLITTLE(p[-1],p[0]); |
| 910 | s = 0; |
| 911 | |
| 912 | /* See how many words we have to shift */ |
| 913 | if (!t) { |
| 914 | /* Shift by words */ |
| 915 | do { |
| 916 | s++; |
| 917 | BIGLITTLE(--p,p++); |
| 918 | } while ((t = BIGLITTLE(p[-1],p[0])) == 0); |
| 919 | size -= s; |
| 920 | s *= 32; |
| 921 | memmove((BNWORD32 *)n->ptr BIG(-size), p BIG(-size), |
| 922 | size * sizeof(BNWORD32)); |
| 923 | p = (BNWORD32 *)n->ptr; |
| 924 | MALLOCDB; |
| 925 | } |
| 926 | |
| 927 | assert(t); |
| 928 | |
| 929 | if (!(t & 1)) { |
| 930 | /* Now count the bits */ |
| 931 | do { |
| 932 | t >>= 1; |
| 933 | s++; |
| 934 | } while ((t & 1) == 0); |
| 935 | |
| 936 | /* Shift the bits */ |
| 937 | lbnRshift_32(p, size, s & (32-1)); |
| 938 | /* Renormalize */ |
| 939 | if (BIGLITTLE(*(p-size),*(p+(size-1))) == 0) |
| 940 | --size; |
| 941 | } |
| 942 | n->size = size; |
| 943 | |
| 944 | MALLOCDB; |
| 945 | return s; |
| 946 | } |
| 947 | |
| 948 | /* |
| 949 | * Do base- and modulus-dependent precomputation for rapid computation of |
| 950 | * base^exp (mod mod) with various exponents. |
| 951 | * |
| 952 | * See lbn32.c for the details on how the algorithm works. Basically, |
| 953 | * it involves precomputing a table of powers of base, base^(order^k), |
| 954 | * for a suitable range 0 <= k < n detemined by the maximum exponent size |
| 955 | * desired. To do eht exponentiation, the exponent is expressed in base |
| 956 | * "order" (sorry for the confusing terminology) and the precomputed powers |
| 957 | * are combined. |
| 958 | * |
| 959 | * This implementation allows only power-of-2 values for "order". Using |
| 960 | * other numbers can be more efficient, but it's more work and for the |
| 961 | * popular exponent size of 320 bits, an order of 8 is optimal, so it |
| 962 | * hasn't seemed worth it to implement. |
| 963 | * |
| 964 | * Here's a table of the optimal power-of-2 order for various exponent |
| 965 | * sizes and the associated (average) cost for an exponentiation. |
| 966 | * Note that *higher* orders are more memory-efficient; the number |
| 967 | * of precomputed values required is ceil(ebits/order). (Ignore the |
| 968 | * underscores in the middle of numbers; they're harmless.) |
| 969 | * |
| 970 | * At 2 bits, order 2 uses 0.000000 multiplies |
| 971 | * At 4 bits, order 2 uses 1.000000 multiplies |
| 972 | * At 8 bits, order 2 uses 3.000000 multiplies |
| 973 | * At 1_6 bits, order 2 uses 7.000000 multiplies |
| 974 | * At 3_2 bits, order 2 uses 15.000000 multiplies |
| 975 | * At 34 bits, 15.750000 (order 4) < 1_6.000000 (order 2) |
| 976 | * At 6_4 bits, order 4 uses 27.000000 multiplies |
| 977 | * At 99 bits, 39.875000 (order 8) < 40.250000 (order 4) |
| 978 | * At 128 bits, order 8 uses 48.500000 multiplies |
| 979 | * At 256 bits, order 8 uses 85.875000 multiplies |
| 980 | * At 280 bits, 92.625000 (order 1_6) < 92.875000 (order 8) |
| 981 | * At 512 bits, order 1_6 uses 147.000000 multiplies |
| 982 | * At 785 bits, 211.093750 (order 3_2) < 211.250000 (order 1_6) |
| 983 | * At 1024 bits, order 3_2 uses 257.562500 multiplies |
| 984 | * At 2048 bits, order 3_2 uses 456.093750 multiplies |
| 985 | * At 2148 bits, 475.406250 (order 6_4) < 475.468750 (order 3_2) |
| 986 | * At 4096 bits, order 6_4 uses 795.281250 multiplies |
| 987 | * At 5726 bits, 1062.609375 (order 128) < 1062.843750 (order 6_4) |
| 988 | * At 8192 bits, order 128 uses 1412.609375 multiplies |
| 989 | * At 14848 bits, 2355.750000 (order 256) < 2355.929688 (order 128) |
| 990 | * At 37593 bits, 5187.841797 (order 512) < 5188.144531 (order 256) |
| 991 | */ |
| 992 | int |
| 993 | bnBasePrecompBegin_32(struct BnBasePrecomp *pre, struct BigNum const *base, |
| 994 | struct BigNum const *mod, unsigned maxebits) |
| 995 | { |
| 996 | int i; |
| 997 | BNWORD32 **array; /* Array of precomputed powers of base */ |
| 998 | unsigned n; /* Number of entries in array (needed) */ |
| 999 | unsigned m; /* Number of entries in array (non-NULL) */ |
| 1000 | unsigned arraysize; /* Number of entries in array (allocated) */ |
| 1001 | unsigned bits; /* log2(order) */ |
| 1002 | unsigned msize = lbnNorm_32((BNWORD32 *)mod->ptr, mod->size); |
| 1003 | static unsigned const bnBasePrecompThreshTable[] = { |
| 1004 | 33, 98, 279, 784, 2147, 5725, 14847, 37592, (unsigned)-1 |
| 1005 | }; |
| 1006 | |
| 1007 | /* Clear pre in case of failure */ |
| 1008 | pre->array = 0; |
| 1009 | pre->msize = 0; |
| 1010 | pre->bits = 0; |
| 1011 | pre->maxebits = 0; |
| 1012 | pre->arraysize = 0; |
| 1013 | pre->entries = 0; |
| 1014 | |
| 1015 | /* Find the correct bit-window size */ |
| 1016 | bits = 0; |
| 1017 | do |
| 1018 | bits++; |
| 1019 | while (maxebits > bnBasePrecompThreshTable[bits]); |
| 1020 | |
| 1021 | /* Now the number of precomputed values we need */ |
| 1022 | n = (maxebits+bits-1)/bits; |
| 1023 | assert(n*bits >= maxebits); |
| 1024 | |
| 1025 | arraysize = n+1; /* Add one trailing NULL for safety */ |
| 1026 | array = lbnMemAlloc(arraysize * sizeof(*array)); |
| 1027 | if (!array) |
| 1028 | return -1; /* Out of memory */ |
| 1029 | |
| 1030 | /* Now allocate the entries (precomputed powers of base) */ |
| 1031 | for (m = 0; m < n; m++) { |
| 1032 | BNWORD32 *entry; |
| 1033 | |
| 1034 | LBNALLOC(entry, BNWORD32, msize); |
| 1035 | if (!entry) |
| 1036 | break; |
| 1037 | array[m] = entry; |
| 1038 | } |
| 1039 | |
| 1040 | /* "m" is the number of successfully allocated entries */ |
| 1041 | if (m < n) { |
| 1042 | /* Ran out of memory; see if we can use a smaller array */ |
| 1043 | BNWORD32 **newarray; |
| 1044 | |
| 1045 | if (m < 2) { |
| 1046 | n = 0; /* Forget it */ |
| 1047 | } else { |
| 1048 | /* How few bits can we use with what's allocated? */ |
| 1049 | bits = (maxebits + m - 1) / m; |
| 1050 | retry: |
| 1051 | n = (maxebits + bits - 1) / bits; |
| 1052 | if (! (n >> bits) ) |
| 1053 | n = 0; /* Not enough to amount to anything */ |
| 1054 | } |
| 1055 | /* Free excess allocated array entries */ |
| 1056 | while (m > n) { |
| 1057 | BNWORD32 *entry = array[--m]; |
| 1058 | LBNFREE(entry, msize); |
| 1059 | } |
| 1060 | if (!n) { |
| 1061 | /* Give it up */ |
| 1062 | lbnMemFree(array, arraysize * sizeof(*array)); |
| 1063 | return -1; |
| 1064 | } |
| 1065 | /* |
| 1066 | * Try to shrink the pointer array. This might fail, but |
| 1067 | * it's not critical. lbnMemRealloc isn't guarnateed to |
| 1068 | * exist, so we may have to allocate, copy, and free. |
| 1069 | */ |
| 1070 | #ifdef lbnMemRealloc |
| 1071 | newarray = lbnMemRealloc(array, arraysize * sizeof(*array), |
| 1072 | (n+1) * sizeof(*array)); |
| 1073 | if (newarray) { |
| 1074 | array = newarray; |
| 1075 | arraysize = n+1; |
| 1076 | } |
| 1077 | #else |
| 1078 | newarray = lbnMemAlloc((n+1) * sizeof(*array)); |
| 1079 | if (newarray) { |
| 1080 | memcpy(newarray, array, n * sizeof(*array)); |
| 1081 | lbnMemFree(array, arraysize * sizeof(*array)); |
| 1082 | array = newarray; |
| 1083 | arraysize = n+1; |
| 1084 | } |
| 1085 | #endif |
| 1086 | } |
| 1087 | |
| 1088 | /* Pad with null pointers */ |
| 1089 | while (m < arraysize) |
| 1090 | array[m++] = 0; |
| 1091 | |
| 1092 | /* Okay, we have our array, now initialize it */ |
| 1093 | i = lbnBasePrecompBegin_32(array, n, bits, |
| 1094 | (BNWORD32 *)base->ptr, base->size, |
| 1095 | (BNWORD32 *)mod->ptr, msize); |
| 1096 | if (i < 0) { |
| 1097 | /* Ack, still out of memory */ |
| 1098 | bits++; |
| 1099 | m = n; |
| 1100 | goto retry; |
| 1101 | } |
| 1102 | /* Finally, totoal success */ |
| 1103 | pre->array = array; |
| 1104 | pre->bits = bits; |
| 1105 | pre->msize = msize; |
| 1106 | pre->maxebits = n * bits; |
| 1107 | pre->arraysize = arraysize; |
| 1108 | pre->entries = n; |
| 1109 | return 0; |
| 1110 | } |
| 1111 | |
| 1112 | /* Free everything preallocated */ |
| 1113 | void |
| 1114 | bnBasePrecompEnd_32(struct BnBasePrecomp *pre) |
| 1115 | { |
| 1116 | BNWORD32 **array = pre->array; |
| 1117 | |
| 1118 | if (array) { |
| 1119 | unsigned entries = pre->entries; |
| 1120 | unsigned msize = pre->msize; |
| 1121 | unsigned m; |
| 1122 | |
| 1123 | for (m = 0; m < entries; m++) { |
| 1124 | BNWORD32 *entry = array[m]; |
| 1125 | if (entry) |
| 1126 | LBNFREE(entry, msize); |
| 1127 | } |
| 1128 | lbnMemFree(array, pre->arraysize * sizeof(array)); |
| 1129 | } |
| 1130 | pre->array = 0; |
| 1131 | pre->bits = 0; |
| 1132 | pre->msize = 0; |
| 1133 | pre->maxebits = 0; |
| 1134 | pre->arraysize = 0; |
| 1135 | pre->entries = 0; |
| 1136 | } |
| 1137 | |
| 1138 | int |
| 1139 | bnBasePrecompExpMod_32(struct BigNum *dest, struct BnBasePrecomp const *pre, |
| 1140 | struct BigNum const *exp, struct BigNum const *mod) |
| 1141 | { |
| 1142 | unsigned msize = lbnNorm_32((BNWORD32 *)mod->ptr, mod->size); |
| 1143 | unsigned esize = lbnNorm_32((BNWORD32 *)exp->ptr, exp->size); |
| 1144 | BNWORD32 const * const *array = pre->array; |
| 1145 | int i; |
| 1146 | |
| 1147 | assert(msize == pre->msize); |
| 1148 | assert(((BNWORD32 *)mod->ptr)[BIGLITTLE(-1,0)] & 1); |
| 1149 | assert(lbnBits_32((BNWORD32 *)exp->ptr, esize) <= pre->maxebits); |
| 1150 | |
| 1151 | bnSizeCheck(dest, msize); |
| 1152 | |
| 1153 | i = lbnBasePrecompExp_32(dest->ptr, array, pre->bits, |
| 1154 | exp->ptr, esize, mod->ptr, msize); |
| 1155 | if (i == 0) |
| 1156 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, msize); |
| 1157 | return i; |
| 1158 | } |
| 1159 | |
| 1160 | int |
| 1161 | bnDoubleBasePrecompExpMod_32(struct BigNum *dest, |
| 1162 | struct BnBasePrecomp const *pre1, struct BigNum const *exp1, |
| 1163 | struct BnBasePrecomp const *pre2, struct BigNum const *exp2, |
| 1164 | struct BigNum const *mod) |
| 1165 | { |
| 1166 | unsigned msize = lbnNorm_32((BNWORD32 *)mod->ptr, mod->size); |
| 1167 | unsigned e1size = lbnNorm_32((BNWORD32 *)exp1->ptr, exp1->size); |
| 1168 | unsigned e2size = lbnNorm_32((BNWORD32 *)exp1->ptr, exp2->size); |
| 1169 | BNWORD32 const * const *array1 = pre1->array; |
| 1170 | BNWORD32 const * const *array2 = pre2->array; |
| 1171 | int i; |
| 1172 | |
| 1173 | assert(msize == pre1->msize); |
| 1174 | assert(msize == pre2->msize); |
| 1175 | assert(((BNWORD32 *)mod->ptr)[BIGLITTLE(-1,0)] & 1); |
| 1176 | assert(lbnBits_32((BNWORD32 *)exp1->ptr, e1size) <= pre1->maxebits); |
| 1177 | assert(lbnBits_32((BNWORD32 *)exp2->ptr, e2size) <= pre2->maxebits); |
| 1178 | assert(pre1->bits == pre2->bits); |
| 1179 | |
| 1180 | bnSizeCheck(dest, msize); |
| 1181 | |
| 1182 | i = lbnDoubleBasePrecompExp_32(dest->ptr, pre1->bits, array1, |
| 1183 | exp1->ptr, e1size, array2, exp2->ptr, e2size, |
| 1184 | mod->ptr, msize); |
| 1185 | if (i == 0) |
| 1186 | dest->size = lbnNorm_32((BNWORD32 *)dest->ptr, msize); |
| 1187 | return i; |
| 1188 | } |