Guido van Rossum | edcc38a | 1991-05-05 20:09:44 +0000 | [diff] [blame^] | 1 | /*********************************************************** |
| 2 | Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The |
| 3 | Netherlands. |
| 4 | |
| 5 | All Rights Reserved |
| 6 | |
| 7 | Permission to use, copy, modify, and distribute this software and its |
| 8 | documentation for any purpose and without fee is hereby granted, |
| 9 | provided that the above copyright notice appear in all copies and that |
| 10 | both that copyright notice and this permission notice appear in |
| 11 | supporting documentation, and that the names of Stichting Mathematisch |
| 12 | Centrum or CWI not be used in advertising or publicity pertaining to |
| 13 | distribution of the software without specific, written prior permission. |
| 14 | |
| 15 | STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO |
| 16 | THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND |
| 17 | FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE |
| 18 | FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 19 | WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| 20 | ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
| 21 | OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| 22 | |
| 23 | ******************************************************************/ |
| 24 | |
| 25 | /* Long (arbitrary precision) integer object implementation */ |
| 26 | |
| 27 | #include "allobjects.h" |
| 28 | #include "longintrepr.h" |
| 29 | #include <assert.h> |
| 30 | |
| 31 | /* Normalize (remove leading zeros from) a long int object. |
| 32 | Doesn't attempt to free the storage--in most cases, due to the nature |
| 33 | of the algorithms used, this could save at most be one word anyway. */ |
| 34 | |
| 35 | longobject * |
| 36 | long_normalize(v) |
| 37 | register longobject *v; |
| 38 | { |
| 39 | int j = ABS(v->ob_size); |
| 40 | register int i = j; |
| 41 | |
| 42 | while (i > 0 && v->ob_digit[i-1] == 0) |
| 43 | --i; |
| 44 | if (i != j) |
| 45 | v->ob_size = (v->ob_size < 0) ? -i : i; |
| 46 | return v; |
| 47 | } |
| 48 | |
| 49 | /* Allocate a new long int object with size digits. |
| 50 | Return NULL and set exception if we run out of memory. */ |
| 51 | |
| 52 | longobject * |
| 53 | alloclongobject(size) |
| 54 | int size; |
| 55 | { |
| 56 | return NEWVAROBJ(longobject, &Longtype, size); |
| 57 | } |
| 58 | |
| 59 | /* Create a new long int object from a C long int */ |
| 60 | |
| 61 | object * |
| 62 | newlongobject(ival) |
| 63 | long ival; |
| 64 | { |
| 65 | /* Assume a C long fits in at most 3 'digits' */ |
| 66 | longobject *v = alloclongobject(3); |
| 67 | if (v != NULL) { |
| 68 | if (ival < 0) { |
| 69 | ival = -ival; |
| 70 | v->ob_size = -v->ob_size; |
| 71 | } |
| 72 | v->ob_digit[0] = ival & MASK; |
| 73 | v->ob_digit[1] = (ival >> SHIFT) & MASK; |
| 74 | v->ob_digit[2] = (ival >> (2*SHIFT)) & MASK; |
| 75 | v = long_normalize(v); |
| 76 | } |
| 77 | return (object *)v; |
| 78 | } |
| 79 | |
| 80 | /* Get a C long int from a long int object. |
| 81 | Returns -1 and sets an error condition if overflow occurs. */ |
| 82 | |
| 83 | long |
| 84 | getlongvalue(vv) |
| 85 | object *vv; |
| 86 | { |
| 87 | register longobject *v; |
| 88 | long x, prev; |
| 89 | int i, sign; |
| 90 | |
| 91 | if (vv == NULL || !is_longobject(vv)) { |
| 92 | err_badcall(); |
| 93 | return -1; |
| 94 | } |
| 95 | v = (longobject *)vv; |
| 96 | i = v->ob_size; |
| 97 | sign = 1; |
| 98 | x = 0; |
| 99 | if (i < 0) { |
| 100 | sign = -1; |
| 101 | i = -i; |
| 102 | } |
| 103 | while (--i >= 0) { |
| 104 | prev = x; |
| 105 | x = (x << SHIFT) + v->ob_digit[i]; |
| 106 | if ((x >> SHIFT) != prev) { |
| 107 | err_setstr(RuntimeError, |
| 108 | "long int too long to convert"); |
| 109 | return -1; |
| 110 | } |
| 111 | } |
| 112 | return x * sign; |
| 113 | } |
| 114 | |
| 115 | /* Get a C double from a long int object. No overflow check. */ |
| 116 | |
| 117 | double |
| 118 | dgetlongvalue(vv) |
| 119 | object *vv; |
| 120 | { |
| 121 | register longobject *v; |
| 122 | double x; |
| 123 | double multiplier = (double) (1L << SHIFT); |
| 124 | int i, sign; |
| 125 | |
| 126 | if (vv == NULL || !is_longobject(vv)) { |
| 127 | err_badcall(); |
| 128 | return -1; |
| 129 | } |
| 130 | v = (longobject *)vv; |
| 131 | i = v->ob_size; |
| 132 | sign = 1; |
| 133 | x = 0.0; |
| 134 | if (i < 0) { |
| 135 | sign = -1; |
| 136 | i = -i; |
| 137 | } |
| 138 | while (--i >= 0) { |
| 139 | x = x*multiplier + v->ob_digit[i]; |
| 140 | } |
| 141 | return x * sign; |
| 142 | } |
| 143 | |
| 144 | /* Multiply by a single digit, ignoring the sign. */ |
| 145 | |
| 146 | longobject * |
| 147 | mul1(a, n) |
| 148 | longobject *a; |
| 149 | digit n; |
| 150 | { |
| 151 | return muladd1(a, n, (digit)0); |
| 152 | } |
| 153 | |
| 154 | /* Multiply by a single digit and add a single digit, ignoring the sign. */ |
| 155 | |
| 156 | longobject * |
| 157 | muladd1(a, n, extra) |
| 158 | longobject *a; |
| 159 | digit n; |
| 160 | digit extra; |
| 161 | { |
| 162 | int size_a = ABS(a->ob_size); |
| 163 | longobject *z = alloclongobject(size_a+1); |
| 164 | twodigits carry = extra; |
| 165 | int i; |
| 166 | |
| 167 | if (z == NULL) |
| 168 | return NULL; |
| 169 | for (i = 0; i < size_a; ++i) { |
| 170 | carry += (twodigits)a->ob_digit[i] * n; |
| 171 | z->ob_digit[i] = carry & MASK; |
| 172 | carry >>= SHIFT; |
| 173 | } |
| 174 | z->ob_digit[i] = carry; |
| 175 | return long_normalize(z); |
| 176 | } |
| 177 | |
| 178 | /* Divide a long integer by a digit, returning both the quotient |
| 179 | (as function result) and the remainder (through *prem). |
| 180 | The sign of a is ignored; n should not be zero. */ |
| 181 | |
| 182 | longobject * |
| 183 | divrem1(a, n, prem) |
| 184 | longobject *a; |
| 185 | digit n; |
| 186 | digit *prem; |
| 187 | { |
| 188 | int size = ABS(a->ob_size); |
| 189 | longobject *z; |
| 190 | int i; |
| 191 | twodigits rem = 0; |
| 192 | |
| 193 | assert(n > 0 && n <= MASK); |
| 194 | z = alloclongobject(size); |
| 195 | if (z == NULL) |
| 196 | return NULL; |
| 197 | for (i = size; --i >= 0; ) { |
| 198 | rem = (rem << SHIFT) + a->ob_digit[i]; |
| 199 | z->ob_digit[i] = rem/n; |
| 200 | rem %= n; |
| 201 | } |
| 202 | *prem = rem; |
| 203 | return long_normalize(z); |
| 204 | } |
| 205 | |
| 206 | /* Convert a long int object to a string, using a given conversion base. |
| 207 | Return a string object. */ |
| 208 | |
| 209 | stringobject * |
| 210 | long_format(a, base) |
| 211 | longobject *a; |
| 212 | int base; |
| 213 | { |
| 214 | stringobject *str; |
| 215 | int i; |
| 216 | int size_a = ABS(a->ob_size); |
| 217 | char *p; |
| 218 | int bits; |
| 219 | char sign = '\0'; |
| 220 | |
| 221 | assert(base >= 2 && base <= 36); |
| 222 | |
| 223 | /* Compute a rough upper bound for the length of the string */ |
| 224 | i = base; |
| 225 | bits = 0; |
| 226 | while (i > 1) { |
| 227 | ++bits; |
| 228 | i >>= 1; |
| 229 | } |
| 230 | i = 1 + (size_a*SHIFT + bits-1) / bits; |
| 231 | str = (stringobject *) newsizedstringobject((char *)0, i); |
| 232 | if (str == NULL) |
| 233 | return NULL; |
| 234 | p = GETSTRINGVALUE(str) + i; |
| 235 | *p = '\0'; |
| 236 | if (a->ob_size < 0) |
| 237 | sign = '-'; |
| 238 | |
| 239 | INCREF(a); |
| 240 | do { |
| 241 | digit rem; |
| 242 | longobject *temp = divrem1(a, (digit)base, &rem); |
| 243 | if (temp == NULL) { |
| 244 | DECREF(a); |
| 245 | DECREF(str); |
| 246 | return NULL; |
| 247 | } |
| 248 | if (rem < 10) |
| 249 | rem += '0'; |
| 250 | else |
| 251 | rem += 'A'-10; |
| 252 | assert(p > GETSTRINGVALUE(str)); |
| 253 | *--p = rem; |
| 254 | DECREF(a); |
| 255 | a = temp; |
| 256 | if (a->ob_size >= INTRLIMIT && intrcheck()) { |
| 257 | DECREF(a); |
| 258 | DECREF(str); |
| 259 | err_set(KeyboardInterrupt); |
| 260 | return NULL; |
| 261 | } |
| 262 | } while (a->ob_size != 0); |
| 263 | DECREF(a); |
| 264 | if (sign) |
| 265 | *--p = sign; |
| 266 | if (p != GETSTRINGVALUE(str)) { |
| 267 | char *q = GETSTRINGVALUE(str); |
| 268 | assert(p > q); |
| 269 | do { |
| 270 | } while ((*q++ = *p++) != '\0'); |
| 271 | resizestring((object **)&str, (int) (q - GETSTRINGVALUE(str))); |
| 272 | } |
| 273 | return str; |
| 274 | } |
| 275 | |
| 276 | /* Convert a string to a long int object, in a given base. |
| 277 | Base zero implies a default depending on the number. */ |
| 278 | |
| 279 | object * |
| 280 | long_scan(str, base) |
| 281 | char *str; |
| 282 | int base; |
| 283 | { |
| 284 | int sign = 1; |
| 285 | longobject *z; |
| 286 | |
| 287 | assert(base == 0 || base >= 2 && base <= 36); |
| 288 | if (*str == '+') |
| 289 | ++str; |
| 290 | else if (*str == '-') { |
| 291 | ++str; |
| 292 | sign = -1; |
| 293 | } |
| 294 | if (base == 0) { |
| 295 | if (str[0] != '0') |
| 296 | base = 10; |
| 297 | else if (str[1] == 'x' || str[1] == 'X') |
| 298 | base = 16; |
| 299 | else |
| 300 | base = 8; |
| 301 | } |
| 302 | if (base == 16 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')) |
| 303 | str += 2; |
| 304 | z = alloclongobject(0); |
| 305 | for ( ; z != NULL; ++str) { |
| 306 | int k = -1; |
| 307 | longobject *temp; |
| 308 | |
| 309 | if (*str <= '9') |
| 310 | k = *str - '0'; |
| 311 | else if (*str >= 'a') |
| 312 | k = *str - 'a' + 10; |
| 313 | else if (*str >= 'A') |
| 314 | k = *str - 'A' + 10; |
| 315 | if (k < 0 || k >= base) |
| 316 | break; |
| 317 | temp = muladd1(z, (digit)base, (digit)k); |
| 318 | DECREF(z); |
| 319 | z = temp; |
| 320 | } |
| 321 | if (z != NULL) |
| 322 | z->ob_size *= sign; |
| 323 | return (object *) z; |
| 324 | } |
| 325 | |
| 326 | static longobject *x_divrem PROTO((longobject *, longobject *, longobject **)); |
| 327 | |
| 328 | /* Long division with remainder, top-level routine */ |
| 329 | |
| 330 | longobject * |
| 331 | long_divrem(a, b, prem) |
| 332 | longobject *a, *b; |
| 333 | longobject **prem; |
| 334 | { |
| 335 | int size_a = ABS(a->ob_size), size_b = ABS(b->ob_size); |
| 336 | longobject *z; |
| 337 | |
| 338 | if (size_b == 0) { |
| 339 | if (prem != NULL) |
| 340 | *prem = NULL; |
| 341 | err_setstr(RuntimeError, "long division by zero"); |
| 342 | return NULL; |
| 343 | } |
| 344 | if (size_a < size_b || |
| 345 | size_a == size_b && a->ob_digit[size_a-1] < b->ob_digit[size_b-1]) { |
| 346 | /* |a| < |b|. */ |
| 347 | if (prem != NULL) { |
| 348 | INCREF(a); |
| 349 | *prem = a; |
| 350 | } |
| 351 | return alloclongobject(0); |
| 352 | } |
| 353 | if (size_b == 1) { |
| 354 | digit rem = 0; |
| 355 | z = divrem1(a, b->ob_digit[0], &rem); |
| 356 | if (prem != NULL) { |
| 357 | if (z == NULL) |
| 358 | *prem = NULL; |
| 359 | else |
| 360 | *prem = (longobject *) |
| 361 | newlongobject((long)rem); |
| 362 | } |
| 363 | } |
| 364 | else |
| 365 | z = x_divrem(a, b, prem); |
| 366 | /* Set the signs. |
| 367 | The quotient z has the sign of a*b; |
| 368 | the remainder r has the sign of a, |
| 369 | so a = b*z + r. */ |
| 370 | if (z != NULL) { |
| 371 | if ((a->ob_size < 0) != (b->ob_size < 0)) |
| 372 | z->ob_size = - z->ob_size; |
| 373 | if (prem != NULL && *prem != NULL && a->ob_size < 0) |
| 374 | (*prem)->ob_size = - (*prem)->ob_size; |
| 375 | } |
| 376 | return z; |
| 377 | } |
| 378 | |
| 379 | /* True unsigned long division with remainder */ |
| 380 | |
| 381 | static longobject * |
| 382 | x_divrem(v1, w1, prem) |
| 383 | longobject *v1, *w1; |
| 384 | longobject **prem; |
| 385 | { |
| 386 | int size_v = ABS(v1->ob_size), size_w = ABS(w1->ob_size); |
| 387 | digit d = (twodigits)BASE / (w1->ob_digit[size_w-1] + 1); |
| 388 | longobject *v = mul1(v1, d); |
| 389 | longobject *w = mul1(w1, d); |
| 390 | longobject *a; |
| 391 | int j, k; |
| 392 | |
| 393 | if (v == NULL || w == NULL) { |
| 394 | XDECREF(v); |
| 395 | XDECREF(w); |
| 396 | if (prem != NULL) |
| 397 | *prem = NULL; |
| 398 | return NULL; |
| 399 | } |
| 400 | |
| 401 | assert(size_v >= size_w && size_w > 1); /* Assert checks by div() */ |
| 402 | assert(v->refcnt == 1); /* Since v will be used as accumulator! */ |
| 403 | assert(size_w == ABS(w->ob_size)); /* That's how d was calculated */ |
| 404 | |
| 405 | size_v = ABS(v->ob_size); |
| 406 | a = alloclongobject(size_v - size_w + 1); |
| 407 | |
| 408 | for (j = size_v, k = a->ob_size-1; a != NULL && k >= 0; --j, --k) { |
| 409 | digit vj = (j >= size_v) ? 0 : v->ob_digit[j]; |
| 410 | twodigits q; |
| 411 | long carry = 0; /* Signed! long! */ |
| 412 | int i; |
| 413 | |
| 414 | if (size_v >= INTRLIMIT && intrcheck()) { |
| 415 | DECREF(a); |
| 416 | a = NULL; |
| 417 | err_set(KeyboardInterrupt); |
| 418 | break; |
| 419 | } |
| 420 | if (vj == w->ob_digit[size_w-1]) |
| 421 | q = MASK; |
| 422 | else |
| 423 | q = (((twodigits)vj << SHIFT) + v->ob_digit[j-1]) / |
| 424 | w->ob_digit[size_w-1]; |
| 425 | |
| 426 | while (w->ob_digit[size_w-2]*q > |
| 427 | (( |
| 428 | ((twodigits)vj << SHIFT) |
| 429 | + v->ob_digit[j-1] |
| 430 | - q*w->ob_digit[size_w-1] |
| 431 | ) << SHIFT) |
| 432 | + v->ob_digit[j-2]) |
| 433 | --q; |
| 434 | |
| 435 | for (i = 0; i < size_w && i+k < size_v; ++i) { |
| 436 | twodigits z = w->ob_digit[i] * q; |
| 437 | digit zz = z >> SHIFT; |
| 438 | carry += v->ob_digit[i+k] - z + ((twodigits)zz << SHIFT); |
| 439 | v->ob_digit[i+k] = carry & MASK; |
| 440 | carry = (carry >> SHIFT) - zz; |
| 441 | } |
| 442 | |
| 443 | if (i+k < size_v) { |
| 444 | carry += v->ob_digit[i+k]; |
| 445 | v->ob_digit[i+k] = 0; |
| 446 | } |
| 447 | |
| 448 | if (carry == 0) |
| 449 | a->ob_digit[k] = q; |
| 450 | else { |
| 451 | assert(carry == -1); |
| 452 | a->ob_digit[k] = q-1; |
| 453 | carry = 0; |
| 454 | for (i = 0; i < size_w && i+k < size_v; ++i) { |
| 455 | carry += v->ob_digit[i+k] + w->ob_digit[i]; |
| 456 | v->ob_digit[i+k] = carry & MASK; |
| 457 | carry >>= SHIFT; |
| 458 | } |
| 459 | } |
| 460 | } /* for j, k */ |
| 461 | |
| 462 | if (a != NULL) |
| 463 | a = long_normalize(a); |
| 464 | if (prem != 0) { |
| 465 | if (a == NULL) |
| 466 | *prem = NULL; |
| 467 | else |
| 468 | *prem = divrem1(v, d, &d); |
| 469 | /* Using d as a dummy to receive the - unused - remainder */ |
| 470 | } |
| 471 | DECREF(v); |
| 472 | DECREF(w); |
| 473 | return a; |
| 474 | } |
| 475 | |
| 476 | /* Methods */ |
| 477 | |
| 478 | static void |
| 479 | long_dealloc(v) |
| 480 | longobject *v; |
| 481 | { |
| 482 | DEL(v); |
| 483 | } |
| 484 | |
| 485 | static void |
| 486 | long_print(v, fp, flags) |
| 487 | longobject *v; |
| 488 | FILE *fp; |
| 489 | int flags; |
| 490 | { |
| 491 | stringobject *str = long_format(v, 10); |
| 492 | if (str == NULL) { |
| 493 | err_clear(); |
| 494 | fprintf(fp, "[err]"); |
| 495 | } |
| 496 | else { |
| 497 | fprintf(fp, "%sL", GETSTRINGVALUE(str)); |
| 498 | DECREF(str); |
| 499 | } |
| 500 | } |
| 501 | |
| 502 | static object * |
| 503 | long_repr(v) |
| 504 | longobject *v; |
| 505 | { |
| 506 | stringobject *str = long_format(v, 10); |
| 507 | if (str != NULL) { |
| 508 | int len = getstringsize((object *)str); |
| 509 | resizestring((object **)&str, len + 1); |
| 510 | if (str != NULL) |
| 511 | GETSTRINGVALUE(str)[len] = 'L'; |
| 512 | } |
| 513 | return (object *)str; |
| 514 | } |
| 515 | |
| 516 | static int |
| 517 | long_compare(a, b) |
| 518 | longobject *a, *b; |
| 519 | { |
| 520 | int sign; |
| 521 | |
| 522 | if (a->ob_size != b->ob_size) |
| 523 | sign = a->ob_size - b->ob_size; |
| 524 | else { |
| 525 | int i = ABS(a->ob_size); |
| 526 | while (--i >= 0 && a->ob_digit[i] == b->ob_digit[i]) |
| 527 | ; |
| 528 | if (i < 0) |
| 529 | sign = 0; |
| 530 | else |
| 531 | sign = (int)a->ob_digit[i] - (int)b->ob_digit[i]; |
| 532 | } |
| 533 | return sign; |
| 534 | } |
| 535 | |
| 536 | /* Add the absolute values of two long integers. */ |
| 537 | |
| 538 | static longobject *x_add PROTO((longobject *, longobject *)); |
| 539 | static longobject * |
| 540 | x_add(a, b) |
| 541 | longobject *a, *b; |
| 542 | { |
| 543 | int size_a = ABS(a->ob_size), size_b = ABS(b->ob_size); |
| 544 | longobject *z; |
| 545 | int i; |
| 546 | digit carry = 0; |
| 547 | |
| 548 | /* Ensure a is the larger of the two: */ |
| 549 | if (size_a < size_b) { |
| 550 | { longobject *temp = a; a = b; b = temp; } |
| 551 | { int size_temp = size_a; size_a = size_b; size_b = size_temp; } |
| 552 | } |
| 553 | z = alloclongobject(size_a+1); |
| 554 | if (z == NULL) |
| 555 | return NULL; |
| 556 | for (i = 0; i < size_b; ++i) { |
| 557 | carry += a->ob_digit[i] + b->ob_digit[i]; |
| 558 | z->ob_digit[i] = carry & MASK; |
| 559 | /* The following assumes unsigned shifts don't |
| 560 | propagate the sign bit. */ |
| 561 | carry >>= SHIFT; |
| 562 | } |
| 563 | for (; i < size_a; ++i) { |
| 564 | carry += a->ob_digit[i]; |
| 565 | z->ob_digit[i] = carry & MASK; |
| 566 | carry >>= SHIFT; |
| 567 | } |
| 568 | z->ob_digit[i] = carry; |
| 569 | return long_normalize(z); |
| 570 | } |
| 571 | |
| 572 | /* Subtract the absolute values of two integers. */ |
| 573 | |
| 574 | static longobject *x_sub PROTO((longobject *, longobject *)); |
| 575 | static longobject * |
| 576 | x_sub(a, b) |
| 577 | longobject *a, *b; |
| 578 | { |
| 579 | int size_a = ABS(a->ob_size), size_b = ABS(b->ob_size); |
| 580 | longobject *z; |
| 581 | int i; |
| 582 | int sign = 1; |
| 583 | digit borrow = 0; |
| 584 | |
| 585 | /* Ensure a is the larger of the two: */ |
| 586 | if (size_a < size_b) { |
| 587 | sign = -1; |
| 588 | { longobject *temp = a; a = b; b = temp; } |
| 589 | { int size_temp = size_a; size_a = size_b; size_b = size_temp; } |
| 590 | } |
| 591 | else if (size_a == size_b) { |
| 592 | /* Find highest digit where a and b differ: */ |
| 593 | i = size_a; |
| 594 | while (--i >= 0 && a->ob_digit[i] == b->ob_digit[i]) |
| 595 | ; |
| 596 | if (i < 0) |
| 597 | return alloclongobject(0); |
| 598 | if (a->ob_digit[i] < b->ob_digit[i]) { |
| 599 | sign = -1; |
| 600 | { longobject *temp = a; a = b; b = temp; } |
| 601 | } |
| 602 | size_a = size_b = i+1; |
| 603 | } |
| 604 | z = alloclongobject(size_a); |
| 605 | if (z == NULL) |
| 606 | return NULL; |
| 607 | for (i = 0; i < size_b; ++i) { |
| 608 | /* The following assumes unsigned arithmetic |
| 609 | works module 2**N for some N>SHIFT. */ |
| 610 | borrow = a->ob_digit[i] - b->ob_digit[i] - borrow; |
| 611 | z->ob_digit[i] = borrow & MASK; |
| 612 | borrow >>= SHIFT; |
| 613 | borrow &= 1; /* Keep only one sign bit */ |
| 614 | } |
| 615 | for (; i < size_a; ++i) { |
| 616 | borrow = a->ob_digit[i] - borrow; |
| 617 | z->ob_digit[i] = borrow & MASK; |
| 618 | borrow >>= SHIFT; |
| 619 | } |
| 620 | assert(borrow == 0); |
| 621 | z->ob_size *= sign; |
| 622 | return long_normalize(z); |
| 623 | } |
| 624 | |
| 625 | static object * |
| 626 | long_add(a, w) |
| 627 | longobject *a; |
| 628 | object *w; |
| 629 | { |
| 630 | longobject *b; |
| 631 | longobject *z; |
| 632 | |
| 633 | if (!is_longobject(w)) { |
| 634 | err_badarg(); |
| 635 | return NULL; |
| 636 | } |
| 637 | b = (longobject *)w; |
| 638 | |
| 639 | if (a->ob_size < 0) { |
| 640 | if (b->ob_size < 0) { |
| 641 | z = x_add(a, b); |
| 642 | if (z != NULL) |
| 643 | z->ob_size = -z->ob_size; |
| 644 | } |
| 645 | else |
| 646 | z = x_sub(b, a); |
| 647 | } |
| 648 | else { |
| 649 | if (b->ob_size < 0) |
| 650 | z = x_sub(a, b); |
| 651 | else |
| 652 | z = x_add(a, b); |
| 653 | } |
| 654 | return (object *)z; |
| 655 | } |
| 656 | |
| 657 | static object * |
| 658 | long_sub(a, w) |
| 659 | longobject *a; |
| 660 | object *w; |
| 661 | { |
| 662 | longobject *b; |
| 663 | longobject *z; |
| 664 | |
| 665 | if (!is_longobject(w)) { |
| 666 | err_badarg(); |
| 667 | return NULL; |
| 668 | } |
| 669 | b = (longobject *)w; |
| 670 | |
| 671 | if (a->ob_size < 0) { |
| 672 | if (b->ob_size < 0) |
| 673 | z = x_sub(a, b); |
| 674 | else |
| 675 | z = x_add(a, b); |
| 676 | if (z != NULL) |
| 677 | z->ob_size = -z->ob_size; |
| 678 | } |
| 679 | else { |
| 680 | if (b->ob_size < 0) |
| 681 | z = x_add(a, b); |
| 682 | else |
| 683 | z = x_sub(a, b); |
| 684 | } |
| 685 | return (object *)z; |
| 686 | } |
| 687 | |
| 688 | static object * |
| 689 | long_mul(a, w) |
| 690 | longobject *a; |
| 691 | object *w; |
| 692 | { |
| 693 | longobject *b; |
| 694 | int size_a; |
| 695 | int size_b; |
| 696 | longobject *z; |
| 697 | int i; |
| 698 | |
| 699 | if (!is_longobject(w)) { |
| 700 | err_badarg(); |
| 701 | return NULL; |
| 702 | } |
| 703 | b = (longobject *)w; |
| 704 | size_a = ABS(a->ob_size); |
| 705 | size_b = ABS(b->ob_size); |
| 706 | z = alloclongobject(size_a + size_b); |
| 707 | if (z == NULL) |
| 708 | return NULL; |
| 709 | for (i = 0; i < z->ob_size; ++i) |
| 710 | z->ob_digit[i] = 0; |
| 711 | for (i = 0; i < size_a; ++i) { |
| 712 | twodigits carry = 0; |
| 713 | twodigits f = a->ob_digit[i]; |
| 714 | int j; |
| 715 | |
| 716 | if (z->ob_size >= INTRLIMIT && intrcheck()) { |
| 717 | DECREF(z); |
| 718 | err_set(KeyboardInterrupt); |
| 719 | return NULL; |
| 720 | } |
| 721 | for (j = 0; j < size_b; ++j) { |
| 722 | carry += z->ob_digit[i+j] + b->ob_digit[j] * f; |
| 723 | z->ob_digit[i+j] = carry & MASK; |
| 724 | carry >>= SHIFT; |
| 725 | } |
| 726 | for (; carry != 0; ++j) { |
| 727 | assert(i+j < z->ob_size); |
| 728 | carry += z->ob_digit[i+j]; |
| 729 | z->ob_digit[i+j] = carry & MASK; |
| 730 | carry >>= SHIFT; |
| 731 | } |
| 732 | } |
| 733 | if (a->ob_size < 0) |
| 734 | z->ob_size = -z->ob_size; |
| 735 | if (b->ob_size < 0) |
| 736 | z->ob_size = -z->ob_size; |
| 737 | return (object *) long_normalize(z); |
| 738 | } |
| 739 | |
| 740 | static object * |
| 741 | long_div(v, w) |
| 742 | longobject *v; |
| 743 | register object *w; |
| 744 | { |
| 745 | if (!is_longobject(w)) { |
| 746 | err_badarg(); |
| 747 | return NULL; |
| 748 | } |
| 749 | return (object *) long_divrem(v, (longobject *)w, (longobject **)0); |
| 750 | } |
| 751 | |
| 752 | static object * |
| 753 | long_rem(v, w) |
| 754 | longobject *v; |
| 755 | register object *w; |
| 756 | { |
| 757 | longobject *div, *rem = NULL; |
| 758 | if (!is_longobject(w)) { |
| 759 | err_badarg(); |
| 760 | return NULL; |
| 761 | } |
| 762 | div = long_divrem(v, (longobject *)w, &rem); |
| 763 | if (div == NULL) { |
| 764 | XDECREF(rem); |
| 765 | rem = NULL; |
| 766 | } |
| 767 | else { |
| 768 | DECREF(div); |
| 769 | } |
| 770 | return (object *) rem; |
| 771 | } |
| 772 | |
| 773 | /* The expression a mod b has the value a - b*floor(a/b). |
| 774 | The divrem function gives the remainder after division of |
| 775 | |a| by |b|, with the sign of a. This is also expressed |
| 776 | as a - b*trunc(a/b), if trunc truncates towards zero. |
| 777 | Some examples: |
| 778 | a b a rem b a mod b |
| 779 | 13 10 3 3 |
| 780 | -13 10 -3 7 |
| 781 | 13 -10 3 -7 |
| 782 | -13 -10 -3 -3 |
| 783 | So, to get from rem to mod, we have to add b if a and b |
| 784 | have different signs. */ |
| 785 | |
| 786 | static object * |
| 787 | long_divmod(v, w) |
| 788 | longobject *v; |
| 789 | register object *w; |
| 790 | { |
| 791 | object *z; |
| 792 | longobject *div, *rem; |
| 793 | if (!is_longobject(w)) { |
| 794 | err_badarg(); |
| 795 | return NULL; |
| 796 | } |
| 797 | div = long_divrem(v, (longobject *)w, &rem); |
| 798 | if (div == NULL) { |
| 799 | XDECREF(rem); |
| 800 | return NULL; |
| 801 | } |
| 802 | if ((v->ob_size < 0) != (((longobject *)w)->ob_size < 0)) { |
| 803 | longobject *temp = (longobject *) long_add(rem, w); |
| 804 | DECREF(rem); |
| 805 | rem = temp; /* XXX ??? was rem = b ??? */ |
| 806 | if (rem == NULL) { |
| 807 | DECREF(div); |
| 808 | return NULL; |
| 809 | } |
| 810 | } |
| 811 | z = newtupleobject(2); |
| 812 | if (z != NULL) { |
| 813 | settupleitem(z, 0, (object *) div); |
| 814 | settupleitem(z, 1, (object *) rem); |
| 815 | } |
| 816 | else { |
| 817 | DECREF(div); |
| 818 | DECREF(rem); |
| 819 | } |
| 820 | return z; |
| 821 | } |
| 822 | |
| 823 | static object * |
| 824 | long_pow(v, w) |
| 825 | longobject *v; |
| 826 | register object *w; |
| 827 | { |
| 828 | if (!is_longobject(w)) { |
| 829 | err_badarg(); |
| 830 | return NULL; |
| 831 | } |
| 832 | err_setstr(SystemError, "long power not implemented"); |
| 833 | return NULL; |
| 834 | } |
| 835 | |
| 836 | static object * |
| 837 | long_pos(v) |
| 838 | longobject *v; |
| 839 | { |
| 840 | INCREF(v); |
| 841 | return (object *)v; |
| 842 | } |
| 843 | |
| 844 | static object * |
| 845 | long_neg(v) |
| 846 | longobject *v; |
| 847 | { |
| 848 | longobject *z; |
| 849 | int i = v->ob_size; |
| 850 | if (i == 0) |
| 851 | return long_pos(v); |
| 852 | i = ABS(i); |
| 853 | z = alloclongobject(i); |
| 854 | if (z != NULL) { |
| 855 | z->ob_size = - v->ob_size; |
| 856 | while (--i >= 0) |
| 857 | z->ob_digit[i] = v->ob_digit[i]; |
| 858 | } |
| 859 | return (object *)z; |
| 860 | } |
| 861 | |
| 862 | static object * |
| 863 | long_abs(v) |
| 864 | longobject *v; |
| 865 | { |
| 866 | if (v->ob_size < 0) |
| 867 | return long_neg(v); |
| 868 | else |
| 869 | return long_pos(v); |
| 870 | } |
| 871 | |
| 872 | static number_methods long_as_number = { |
| 873 | long_add, /*nb_add*/ |
| 874 | long_sub, /*nb_subtract*/ |
| 875 | long_mul, /*nb_multiply*/ |
| 876 | long_div, /*nb_divide*/ |
| 877 | long_rem, /*nb_remainder*/ |
| 878 | long_divmod, /*nb_divmod*/ |
| 879 | long_pow, /*nb_power*/ |
| 880 | long_neg, /*nb_negative*/ |
| 881 | long_pos, /*tp_positive*/ |
| 882 | long_abs, /*tp_absolute*/ |
| 883 | }; |
| 884 | |
| 885 | typeobject Longtype = { |
| 886 | OB_HEAD_INIT(&Typetype) |
| 887 | 0, |
| 888 | "long int", |
| 889 | sizeof(longobject) - sizeof(digit), |
| 890 | sizeof(digit), |
| 891 | long_dealloc, /*tp_dealloc*/ |
| 892 | long_print, /*tp_print*/ |
| 893 | 0, /*tp_getattr*/ |
| 894 | 0, /*tp_setattr*/ |
| 895 | long_compare, /*tp_compare*/ |
| 896 | long_repr, /*tp_repr*/ |
| 897 | &long_as_number,/*tp_as_number*/ |
| 898 | 0, /*tp_as_sequence*/ |
| 899 | 0, /*tp_as_mapping*/ |
| 900 | }; |