1 /* numeric.c 2 * 3 * Copyright (c) 2001-2002, Larry Wall 4 * 5 * You may distribute under the terms of either the GNU General Public 6 * License or the Artistic License, as specified in the README file. 7 * 8 */ 9 10 /* 11 * "That only makes eleven (plus one mislaid) and not fourteen, unless 12 * wizards count differently to other people." 13 */ 14 15 /* 16 =head1 Numeric functions 17 */ 18 19 #include "EXTERN.h" 20 #define PERL_IN_NUMERIC_C 21 #include "perl.h" 22 23 U32 24 Perl_cast_ulong(pTHX_ NV f) 25 { 26 if (f < 0.0) 27 return f < I32_MIN ? (U32) I32_MIN : (U32)(I32) f; 28 if (f < U32_MAX_P1) { 29 #if CASTFLAGS & 2 30 if (f < U32_MAX_P1_HALF) 31 return (U32) f; 32 f -= U32_MAX_P1_HALF; 33 return ((U32) f) | (1 + U32_MAX >> 1); 34 #else 35 return (U32) f; 36 #endif 37 } 38 return f > 0 ? U32_MAX : 0 /* NaN */; 39 } 40 41 I32 42 Perl_cast_i32(pTHX_ NV f) 43 { 44 if (f < I32_MAX_P1) 45 return f < I32_MIN ? I32_MIN : (I32) f; 46 if (f < U32_MAX_P1) { 47 #if CASTFLAGS & 2 48 if (f < U32_MAX_P1_HALF) 49 return (I32)(U32) f; 50 f -= U32_MAX_P1_HALF; 51 return (I32)(((U32) f) | (1 + U32_MAX >> 1)); 52 #else 53 return (I32)(U32) f; 54 #endif 55 } 56 return f > 0 ? (I32)U32_MAX : 0 /* NaN */; 57 } 58 59 IV 60 Perl_cast_iv(pTHX_ NV f) 61 { 62 if (f < IV_MAX_P1) 63 return f < IV_MIN ? IV_MIN : (IV) f; 64 if (f < UV_MAX_P1) { 65 #if CASTFLAGS & 2 66 /* For future flexibility allowing for sizeof(UV) >= sizeof(IV) */ 67 if (f < UV_MAX_P1_HALF) 68 return (IV)(UV) f; 69 f -= UV_MAX_P1_HALF; 70 return (IV)(((UV) f) | (1 + UV_MAX >> 1)); 71 #else 72 return (IV)(UV) f; 73 #endif 74 } 75 return f > 0 ? (IV)UV_MAX : 0 /* NaN */; 76 } 77 78 UV 79 Perl_cast_uv(pTHX_ NV f) 80 { 81 if (f < 0.0) 82 return f < IV_MIN ? (UV) IV_MIN : (UV)(IV) f; 83 if (f < UV_MAX_P1) { 84 #if CASTFLAGS & 2 85 if (f < UV_MAX_P1_HALF) 86 return (UV) f; 87 f -= UV_MAX_P1_HALF; 88 return ((UV) f) | (1 + UV_MAX >> 1); 89 #else 90 return (UV) f; 91 #endif 92 } 93 return f > 0 ? UV_MAX : 0 /* NaN */; 94 } 95 96 #if defined(HUGE_VAL) || (defined(USE_LONG_DOUBLE) && defined(HUGE_VALL)) 97 /* 98 * This hack is to force load of "huge" support from libm.a 99 * So it is in perl for (say) POSIX to use. 100 * Needed for SunOS with Sun's 'acc' for example. 101 */ 102 NV 103 Perl_huge(void) 104 { 105 # if defined(USE_LONG_DOUBLE) && defined(HUGE_VALL) 106 return HUGE_VALL; 107 # endif 108 return HUGE_VAL; 109 } 110 #endif 111 112 /* 113 =for apidoc grok_bin 114 115 converts a string representing a binary number to numeric form. 116 117 On entry I<start> and I<*len> give the string to scan, I<*flags> gives 118 conversion flags, and I<result> should be NULL or a pointer to an NV. 119 The scan stops at the end of the string, or the first invalid character. 120 On return I<*len> is set to the length scanned string, and I<*flags> gives 121 output flags. 122 123 If the value is <= UV_MAX it is returned as a UV, the output flags are clear, 124 and nothing is written to I<*result>. If the value is > UV_MAX C<grok_bin> 125 returns UV_MAX, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags, 126 and writes the value to I<*result> (or the value is discarded if I<result> 127 is NULL). 128 129 The hex number may optionally be prefixed with "0b" or "b" unless 130 C<PERL_SCAN_DISALLOW_PREFIX> is set in I<*flags> on entry. If 131 C<PERL_SCAN_ALLOW_UNDERSCORES> is set in I<*flags> then the binary 132 number may use '_' characters to separate digits. 133 134 =cut 135 */ 136 137 UV 138 Perl_grok_bin(pTHX_ char *start, STRLEN *len_p, I32 *flags, NV *result) { 139 const char *s = start; 140 STRLEN len = *len_p; 141 UV value = 0; 142 NV value_nv = 0; 143 144 const UV max_div_2 = UV_MAX / 2; 145 bool allow_underscores = *flags & PERL_SCAN_ALLOW_UNDERSCORES; 146 bool overflowed = FALSE; 147 148 if (!(*flags & PERL_SCAN_DISALLOW_PREFIX)) { 149 /* strip off leading b or 0b. 150 for compatibility silently suffer "b" and "0b" as valid binary 151 numbers. */ 152 if (len >= 1) { 153 if (s[0] == 'b') { 154 s++; 155 len--; 156 } 157 else if (len >= 2 && s[0] == '0' && s[1] == 'b') { 158 s+=2; 159 len-=2; 160 } 161 } 162 } 163 164 for (; len-- && *s; s++) { 165 char bit = *s; 166 if (bit == '0' || bit == '1') { 167 /* Write it in this wonky order with a goto to attempt to get the 168 compiler to make the common case integer-only loop pretty tight. 169 With gcc seems to be much straighter code than old scan_bin. */ 170 redo: 171 if (!overflowed) { 172 if (value <= max_div_2) { 173 value = (value << 1) | (bit - '0'); 174 continue; 175 } 176 /* Bah. We're just overflowed. */ 177 if (ckWARN_d(WARN_OVERFLOW)) 178 Perl_warner(aTHX_ packWARN(WARN_OVERFLOW), 179 "Integer overflow in binary number"); 180 overflowed = TRUE; 181 value_nv = (NV) value; 182 } 183 value_nv *= 2.0; 184 /* If an NV has not enough bits in its mantissa to 185 * represent a UV this summing of small low-order numbers 186 * is a waste of time (because the NV cannot preserve 187 * the low-order bits anyway): we could just remember when 188 * did we overflow and in the end just multiply value_nv by the 189 * right amount. */ 190 value_nv += (NV)(bit - '0'); 191 continue; 192 } 193 if (bit == '_' && len && allow_underscores && (bit = s[1]) 194 && (bit == '0' || bit == '1')) 195 { 196 --len; 197 ++s; 198 goto redo; 199 } 200 if (ckWARN(WARN_DIGIT)) 201 Perl_warner(aTHX_ packWARN(WARN_DIGIT), 202 "Illegal binary digit '%c' ignored", *s); 203 break; 204 } 205 206 if ( ( overflowed && value_nv > 4294967295.0) 207 #if UVSIZE > 4 208 || (!overflowed && value > 0xffffffff ) 209 #endif 210 ) { 211 if (ckWARN(WARN_PORTABLE)) 212 Perl_warner(aTHX_ packWARN(WARN_PORTABLE), 213 "Binary number > 0b11111111111111111111111111111111 non-portable"); 214 } 215 *len_p = s - start; 216 if (!overflowed) { 217 *flags = 0; 218 return value; 219 } 220 *flags = PERL_SCAN_GREATER_THAN_UV_MAX; 221 if (result) 222 *result = value_nv; 223 return UV_MAX; 224 } 225 226 /* 227 =for apidoc grok_hex 228 229 converts a string representing a hex number to numeric form. 230 231 On entry I<start> and I<*len> give the string to scan, I<*flags> gives 232 conversion flags, and I<result> should be NULL or a pointer to an NV. 233 The scan stops at the end of the string, or the first non-hex-digit character. 234 On return I<*len> is set to the length scanned string, and I<*flags> gives 235 output flags. 236 237 If the value is <= UV_MAX it is returned as a UV, the output flags are clear, 238 and nothing is written to I<*result>. If the value is > UV_MAX C<grok_hex> 239 returns UV_MAX, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags, 240 and writes the value to I<*result> (or the value is discarded if I<result> 241 is NULL). 242 243 The hex number may optionally be prefixed with "0x" or "x" unless 244 C<PERL_SCAN_DISALLOW_PREFIX> is set in I<*flags> on entry. If 245 C<PERL_SCAN_ALLOW_UNDERSCORES> is set in I<*flags> then the hex 246 number may use '_' characters to separate digits. 247 248 =cut 249 */ 250 251 UV 252 Perl_grok_hex(pTHX_ char *start, STRLEN *len_p, I32 *flags, NV *result) { 253 const char *s = start; 254 STRLEN len = *len_p; 255 UV value = 0; 256 NV value_nv = 0; 257 258 const UV max_div_16 = UV_MAX / 16; 259 bool allow_underscores = *flags & PERL_SCAN_ALLOW_UNDERSCORES; 260 bool overflowed = FALSE; 261 const char *hexdigit; 262 263 if (!(*flags & PERL_SCAN_DISALLOW_PREFIX)) { 264 /* strip off leading x or 0x. 265 for compatibility silently suffer "x" and "0x" as valid hex numbers. 266 */ 267 if (len >= 1) { 268 if (s[0] == 'x') { 269 s++; 270 len--; 271 } 272 else if (len >= 2 && s[0] == '0' && s[1] == 'x') { 273 s+=2; 274 len-=2; 275 } 276 } 277 } 278 279 for (; len-- && *s; s++) { 280 hexdigit = strchr((char *) PL_hexdigit, *s); 281 if (hexdigit) { 282 /* Write it in this wonky order with a goto to attempt to get the 283 compiler to make the common case integer-only loop pretty tight. 284 With gcc seems to be much straighter code than old scan_hex. */ 285 redo: 286 if (!overflowed) { 287 if (value <= max_div_16) { 288 value = (value << 4) | ((hexdigit - PL_hexdigit) & 15); 289 continue; 290 } 291 /* Bah. We're just overflowed. */ 292 if (ckWARN_d(WARN_OVERFLOW)) 293 Perl_warner(aTHX_ packWARN(WARN_OVERFLOW), 294 "Integer overflow in hexadecimal number"); 295 overflowed = TRUE; 296 value_nv = (NV) value; 297 } 298 value_nv *= 16.0; 299 /* If an NV has not enough bits in its mantissa to 300 * represent a UV this summing of small low-order numbers 301 * is a waste of time (because the NV cannot preserve 302 * the low-order bits anyway): we could just remember when 303 * did we overflow and in the end just multiply value_nv by the 304 * right amount of 16-tuples. */ 305 value_nv += (NV)((hexdigit - PL_hexdigit) & 15); 306 continue; 307 } 308 if (*s == '_' && len && allow_underscores && s[1] 309 && (hexdigit = strchr((char *) PL_hexdigit, s[1]))) 310 { 311 --len; 312 ++s; 313 goto redo; 314 } 315 if (ckWARN(WARN_DIGIT)) 316 Perl_warner(aTHX_ packWARN(WARN_DIGIT), 317 "Illegal hexadecimal digit '%c' ignored", *s); 318 break; 319 } 320 321 if ( ( overflowed && value_nv > 4294967295.0) 322 #if UVSIZE > 4 323 || (!overflowed && value > 0xffffffff ) 324 #endif 325 ) { 326 if (ckWARN(WARN_PORTABLE)) 327 Perl_warner(aTHX_ packWARN(WARN_PORTABLE), 328 "Hexadecimal number > 0xffffffff non-portable"); 329 } 330 *len_p = s - start; 331 if (!overflowed) { 332 *flags = 0; 333 return value; 334 } 335 *flags = PERL_SCAN_GREATER_THAN_UV_MAX; 336 if (result) 337 *result = value_nv; 338 return UV_MAX; 339 } 340 341 /* 342 =for apidoc grok_oct 343 344 345 =cut 346 */ 347 348 UV 349 Perl_grok_oct(pTHX_ char *start, STRLEN *len_p, I32 *flags, NV *result) { 350 const char *s = start; 351 STRLEN len = *len_p; 352 UV value = 0; 353 NV value_nv = 0; 354 355 const UV max_div_8 = UV_MAX / 8; 356 bool allow_underscores = *flags & PERL_SCAN_ALLOW_UNDERSCORES; 357 bool overflowed = FALSE; 358 359 for (; len-- && *s; s++) { 360 /* gcc 2.95 optimiser not smart enough to figure that this subtraction 361 out front allows slicker code. */ 362 int digit = *s - '0'; 363 if (digit >= 0 && digit <= 7) { 364 /* Write it in this wonky order with a goto to attempt to get the 365 compiler to make the common case integer-only loop pretty tight. 366 */ 367 redo: 368 if (!overflowed) { 369 if (value <= max_div_8) { 370 value = (value << 3) | digit; 371 continue; 372 } 373 /* Bah. We're just overflowed. */ 374 if (ckWARN_d(WARN_OVERFLOW)) 375 Perl_warner(aTHX_ packWARN(WARN_OVERFLOW), 376 "Integer overflow in octal number"); 377 overflowed = TRUE; 378 value_nv = (NV) value; 379 } 380 value_nv *= 8.0; 381 /* If an NV has not enough bits in its mantissa to 382 * represent a UV this summing of small low-order numbers 383 * is a waste of time (because the NV cannot preserve 384 * the low-order bits anyway): we could just remember when 385 * did we overflow and in the end just multiply value_nv by the 386 * right amount of 8-tuples. */ 387 value_nv += (NV)digit; 388 continue; 389 } 390 if (digit == ('_' - '0') && len && allow_underscores 391 && (digit = s[1] - '0') && (digit >= 0 && digit <= 7)) 392 { 393 --len; 394 ++s; 395 goto redo; 396 } 397 /* Allow \octal to work the DWIM way (that is, stop scanning 398 * as soon as non-octal characters are seen, complain only iff 399 * someone seems to want to use the digits eight and nine). */ 400 if (digit == 8 || digit == 9) { 401 if (ckWARN(WARN_DIGIT)) 402 Perl_warner(aTHX_ packWARN(WARN_DIGIT), 403 "Illegal octal digit '%c' ignored", *s); 404 } 405 break; 406 } 407 408 if ( ( overflowed && value_nv > 4294967295.0) 409 #if UVSIZE > 4 410 || (!overflowed && value > 0xffffffff ) 411 #endif 412 ) { 413 if (ckWARN(WARN_PORTABLE)) 414 Perl_warner(aTHX_ packWARN(WARN_PORTABLE), 415 "Octal number > 037777777777 non-portable"); 416 } 417 *len_p = s - start; 418 if (!overflowed) { 419 *flags = 0; 420 return value; 421 } 422 *flags = PERL_SCAN_GREATER_THAN_UV_MAX; 423 if (result) 424 *result = value_nv; 425 return UV_MAX; 426 } 427 428 /* 429 =for apidoc scan_bin 430 431 For backwards compatibility. Use C<grok_bin> instead. 432 433 =for apidoc scan_hex 434 435 For backwards compatibility. Use C<grok_hex> instead. 436 437 =for apidoc scan_oct 438 439 For backwards compatibility. Use C<grok_oct> instead. 440 441 =cut 442 */ 443 444 NV 445 Perl_scan_bin(pTHX_ char *start, STRLEN len, STRLEN *retlen) 446 { 447 NV rnv; 448 I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0; 449 UV ruv = grok_bin (start, &len, &flags, &rnv); 450 451 *retlen = len; 452 return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv; 453 } 454 455 NV 456 Perl_scan_oct(pTHX_ char *start, STRLEN len, STRLEN *retlen) 457 { 458 NV rnv; 459 I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0; 460 UV ruv = grok_oct (start, &len, &flags, &rnv); 461 462 *retlen = len; 463 return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv; 464 } 465 466 NV 467 Perl_scan_hex(pTHX_ char *start, STRLEN len, STRLEN *retlen) 468 { 469 NV rnv; 470 I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0; 471 UV ruv = grok_hex (start, &len, &flags, &rnv); 472 473 *retlen = len; 474 return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv; 475 } 476 477 /* 478 =for apidoc grok_numeric_radix 479 480 Scan and skip for a numeric decimal separator (radix). 481 482 =cut 483 */ 484 bool 485 Perl_grok_numeric_radix(pTHX_ const char **sp, const char *send) 486 { 487 #ifdef USE_LOCALE_NUMERIC 488 if (PL_numeric_radix_sv && IN_LOCALE) { 489 STRLEN len; 490 char* radix = SvPV(PL_numeric_radix_sv, len); 491 if (*sp + len <= send && memEQ(*sp, radix, len)) { 492 *sp += len; 493 return TRUE; 494 } 495 } 496 /* always try "." if numeric radix didn't match because 497 * we may have data from different locales mixed */ 498 #endif 499 if (*sp < send && **sp == '.') { 500 ++*sp; 501 return TRUE; 502 } 503 return FALSE; 504 } 505 506 /* 507 =for apidoc grok_number 508 509 Recognise (or not) a number. The type of the number is returned 510 (0 if unrecognised), otherwise it is a bit-ORed combination of 511 IS_NUMBER_IN_UV, IS_NUMBER_GREATER_THAN_UV_MAX, IS_NUMBER_NOT_INT, 512 IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUMBER_NAN (defined in perl.h). 513 514 If the value of the number can fit an in UV, it is returned in the *valuep 515 IS_NUMBER_IN_UV will be set to indicate that *valuep is valid, IS_NUMBER_IN_UV 516 will never be set unless *valuep is valid, but *valuep may have been assigned 517 to during processing even though IS_NUMBER_IN_UV is not set on return. 518 If valuep is NULL, IS_NUMBER_IN_UV will be set for the same cases as when 519 valuep is non-NULL, but no actual assignment (or SEGV) will occur. 520 521 IS_NUMBER_NOT_INT will be set with IS_NUMBER_IN_UV if trailing decimals were 522 seen (in which case *valuep gives the true value truncated to an integer), and 523 IS_NUMBER_NEG if the number is negative (in which case *valuep holds the 524 absolute value). IS_NUMBER_IN_UV is not set if e notation was used or the 525 number is larger than a UV. 526 527 =cut 528 */ 529 int 530 Perl_grok_number(pTHX_ const char *pv, STRLEN len, UV *valuep) 531 { 532 const char *s = pv; 533 const char *send = pv + len; 534 const UV max_div_10 = UV_MAX / 10; 535 const char max_mod_10 = UV_MAX % 10; 536 int numtype = 0; 537 int sawinf = 0; 538 int sawnan = 0; 539 540 while (s < send && isSPACE(*s)) 541 s++; 542 if (s == send) { 543 return 0; 544 } else if (*s == '-') { 545 s++; 546 numtype = IS_NUMBER_NEG; 547 } 548 else if (*s == '+') 549 s++; 550 551 if (s == send) 552 return 0; 553 554 /* next must be digit or the radix separator or beginning of infinity */ 555 if (isDIGIT(*s)) { 556 /* UVs are at least 32 bits, so the first 9 decimal digits cannot 557 overflow. */ 558 UV value = *s - '0'; 559 /* This construction seems to be more optimiser friendly. 560 (without it gcc does the isDIGIT test and the *s - '0' separately) 561 With it gcc on arm is managing 6 instructions (6 cycles) per digit. 562 In theory the optimiser could deduce how far to unroll the loop 563 before checking for overflow. */ 564 if (++s < send) { 565 int digit = *s - '0'; 566 if (digit >= 0 && digit <= 9) { 567 value = value * 10 + digit; 568 if (++s < send) { 569 digit = *s - '0'; 570 if (digit >= 0 && digit <= 9) { 571 value = value * 10 + digit; 572 if (++s < send) { 573 digit = *s - '0'; 574 if (digit >= 0 && digit <= 9) { 575 value = value * 10 + digit; 576 if (++s < send) { 577 digit = *s - '0'; 578 if (digit >= 0 && digit <= 9) { 579 value = value * 10 + digit; 580 if (++s < send) { 581 digit = *s - '0'; 582 if (digit >= 0 && digit <= 9) { 583 value = value * 10 + digit; 584 if (++s < send) { 585 digit = *s - '0'; 586 if (digit >= 0 && digit <= 9) { 587 value = value * 10 + digit; 588 if (++s < send) { 589 digit = *s - '0'; 590 if (digit >= 0 && digit <= 9) { 591 value = value * 10 + digit; 592 if (++s < send) { 593 digit = *s - '0'; 594 if (digit >= 0 && digit <= 9) { 595 value = value * 10 + digit; 596 if (++s < send) { 597 /* Now got 9 digits, so need to check 598 each time for overflow. */ 599 digit = *s - '0'; 600 while (digit >= 0 && digit <= 9 601 && (value < max_div_10 602 || (value == max_div_10 603 && digit <= max_mod_10))) { 604 value = value * 10 + digit; 605 if (++s < send) 606 digit = *s - '0'; 607 else 608 break; 609 } 610 if (digit >= 0 && digit <= 9 611 && (s < send)) { 612 /* value overflowed. 613 skip the remaining digits, don't 614 worry about setting *valuep. */ 615 do { 616 s++; 617 } while (s < send && isDIGIT(*s)); 618 numtype |= 619 IS_NUMBER_GREATER_THAN_UV_MAX; 620 goto skip_value; 621 } 622 } 623 } 624 } 625 } 626 } 627 } 628 } 629 } 630 } 631 } 632 } 633 } 634 } 635 } 636 } 637 } 638 } 639 numtype |= IS_NUMBER_IN_UV; 640 if (valuep) 641 *valuep = value; 642 643 skip_value: 644 if (GROK_NUMERIC_RADIX(&s, send)) { 645 numtype |= IS_NUMBER_NOT_INT; 646 while (s < send && isDIGIT(*s)) /* optional digits after the radix */ 647 s++; 648 } 649 } 650 else if (GROK_NUMERIC_RADIX(&s, send)) { 651 numtype |= IS_NUMBER_NOT_INT | IS_NUMBER_IN_UV; /* valuep assigned below */ 652 /* no digits before the radix means we need digits after it */ 653 if (s < send && isDIGIT(*s)) { 654 do { 655 s++; 656 } while (s < send && isDIGIT(*s)); 657 if (valuep) { 658 /* integer approximation is valid - it's 0. */ 659 *valuep = 0; 660 } 661 } 662 else 663 return 0; 664 } else if (*s == 'I' || *s == 'i') { 665 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0; 666 s++; if (s == send || (*s != 'F' && *s != 'f')) return 0; 667 s++; if (s < send && (*s == 'I' || *s == 'i')) { 668 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0; 669 s++; if (s == send || (*s != 'I' && *s != 'i')) return 0; 670 s++; if (s == send || (*s != 'T' && *s != 't')) return 0; 671 s++; if (s == send || (*s != 'Y' && *s != 'y')) return 0; 672 s++; 673 } 674 sawinf = 1; 675 } else if (*s == 'N' || *s == 'n') { 676 /* XXX TODO: There are signaling NaNs and quiet NaNs. */ 677 s++; if (s == send || (*s != 'A' && *s != 'a')) return 0; 678 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0; 679 s++; 680 sawnan = 1; 681 } else 682 return 0; 683 684 if (sawinf) { 685 numtype &= IS_NUMBER_NEG; /* Keep track of sign */ 686 numtype |= IS_NUMBER_INFINITY | IS_NUMBER_NOT_INT; 687 } else if (sawnan) { 688 numtype &= IS_NUMBER_NEG; /* Keep track of sign */ 689 numtype |= IS_NUMBER_NAN | IS_NUMBER_NOT_INT; 690 } else if (s < send) { 691 /* we can have an optional exponent part */ 692 if (*s == 'e' || *s == 'E') { 693 /* The only flag we keep is sign. Blow away any "it's UV" */ 694 numtype &= IS_NUMBER_NEG; 695 numtype |= IS_NUMBER_NOT_INT; 696 s++; 697 if (s < send && (*s == '-' || *s == '+')) 698 s++; 699 if (s < send && isDIGIT(*s)) { 700 do { 701 s++; 702 } while (s < send && isDIGIT(*s)); 703 } 704 else 705 return 0; 706 } 707 } 708 while (s < send && isSPACE(*s)) 709 s++; 710 if (s >= send) 711 return numtype; 712 if (len == 10 && memEQ(pv, "0 but true", 10)) { 713 if (valuep) 714 *valuep = 0; 715 return IS_NUMBER_IN_UV; 716 } 717 return 0; 718 } 719 720 NV 721 S_mulexp10(NV value, I32 exponent) 722 { 723 NV result = 1.0; 724 NV power = 10.0; 725 bool negative = 0; 726 I32 bit; 727 728 if (exponent == 0) 729 return value; 730 731 /* On OpenVMS VAX we by default use the D_FLOAT double format, 732 * and that format does not have *easy* capabilities [1] for 733 * overflowing doubles 'silently' as IEEE fp does. We also need 734 * to support G_FLOAT on both VAX and Alpha, and though the exponent 735 * range is much larger than D_FLOAT it still doesn't do silent 736 * overflow. Therefore we need to detect early whether we would 737 * overflow (this is the behaviour of the native string-to-float 738 * conversion routines, and therefore of native applications, too). 739 * 740 * [1] Trying to establish a condition handler to trap floating point 741 * exceptions is not a good idea. */ 742 743 /* In UNICOS and in certain Cray models (such as T90) there is no 744 * IEEE fp, and no way at all from C to catch fp overflows gracefully. 745 * There is something you can do if you are willing to use some 746 * inline assembler: the instruction is called DFI-- but that will 747 * disable *all* floating point interrupts, a little bit too large 748 * a hammer. Therefore we need to catch potential overflows before 749 * it's too late. */ 750 751 #if ((defined(VMS) && !defined(__IEEE_FP)) || defined(_UNICOS)) && defined(NV_MAX_10_EXP) 752 STMT_START { 753 NV exp_v = log10(value); 754 if (exponent >= NV_MAX_10_EXP || exponent + exp_v >= NV_MAX_10_EXP) 755 return NV_MAX; 756 if (exponent < 0) { 757 if (-(exponent + exp_v) >= NV_MAX_10_EXP) 758 return 0.0; 759 while (-exponent >= NV_MAX_10_EXP) { 760 /* combination does not overflow, but 10^(-exponent) does */ 761 value /= 10; 762 ++exponent; 763 } 764 } 765 } STMT_END; 766 #endif 767 768 if (exponent < 0) { 769 negative = 1; 770 exponent = -exponent; 771 } 772 for (bit = 1; exponent; bit <<= 1) { 773 if (exponent & bit) { 774 exponent ^= bit; 775 result *= power; 776 /* Floating point exceptions are supposed to be turned off, 777 * but if we're obviously done, don't risk another iteration. 778 */ 779 if (exponent == 0) break; 780 } 781 power *= power; 782 } 783 return negative ? value / result : value * result; 784 } 785 786 NV 787 Perl_my_atof(pTHX_ const char* s) 788 { 789 NV x = 0.0; 790 #ifdef USE_LOCALE_NUMERIC 791 if (PL_numeric_local && IN_LOCALE) { 792 NV y; 793 794 /* Scan the number twice; once using locale and once without; 795 * choose the larger result (in absolute value). */ 796 Perl_atof2(s, x); 797 SET_NUMERIC_STANDARD(); 798 Perl_atof2(s, y); 799 SET_NUMERIC_LOCAL(); 800 if ((y < 0.0 && y < x) || (y > 0.0 && y > x)) 801 return y; 802 } 803 else 804 Perl_atof2(s, x); 805 #else 806 Perl_atof2(s, x); 807 #endif 808 return x; 809 } 810 811 char* 812 Perl_my_atof2(pTHX_ const char* orig, NV* value) 813 { 814 NV result = 0.0; 815 char* s = (char*)orig; 816 #ifdef USE_PERL_ATOF 817 bool negative = 0; 818 char* send = s + strlen(orig) - 1; 819 bool seendigit = 0; 820 I32 expextra = 0; 821 I32 exponent = 0; 822 I32 i; 823 /* this is arbitrary */ 824 #define PARTLIM 6 825 /* we want the largest integers we can usefully use */ 826 #if defined(HAS_QUAD) && defined(USE_64_BIT_INT) 827 # define PARTSIZE ((int)TYPE_DIGITS(U64)-1) 828 U64 part[PARTLIM]; 829 #else 830 # define PARTSIZE ((int)TYPE_DIGITS(U32)-1) 831 U32 part[PARTLIM]; 832 #endif 833 I32 ipart = 0; /* index into part[] */ 834 I32 offcount; /* number of digits in least significant part */ 835 836 /* leading whitespace */ 837 while (isSPACE(*s)) 838 ++s; 839 840 /* sign */ 841 switch (*s) { 842 case '-': 843 negative = 1; 844 /* fall through */ 845 case '+': 846 ++s; 847 } 848 849 part[0] = offcount = 0; 850 if (isDIGIT(*s)) { 851 seendigit = 1; /* get this over with */ 852 853 /* skip leading zeros */ 854 while (*s == '0') 855 ++s; 856 } 857 858 /* integer digits */ 859 while (isDIGIT(*s)) { 860 if (++offcount > PARTSIZE) { 861 if (++ipart < PARTLIM) { 862 part[ipart] = 0; 863 offcount = 1; /* ++0 */ 864 } 865 else { 866 /* limits of precision reached */ 867 --ipart; 868 --offcount; 869 if (*s >= '5') 870 ++part[ipart]; 871 while (isDIGIT(*s)) { 872 ++expextra; 873 ++s; 874 } 875 /* warn of loss of precision? */ 876 break; 877 } 878 } 879 part[ipart] = part[ipart] * 10 + (*s++ - '0'); 880 } 881 882 /* decimal point */ 883 if (GROK_NUMERIC_RADIX((const char **)&s, send)) { 884 if (isDIGIT(*s)) 885 seendigit = 1; /* get this over with */ 886 887 /* decimal digits */ 888 while (isDIGIT(*s)) { 889 if (++offcount > PARTSIZE) { 890 if (++ipart < PARTLIM) { 891 part[ipart] = 0; 892 offcount = 1; /* ++0 */ 893 } 894 else { 895 /* limits of precision reached */ 896 --ipart; 897 --offcount; 898 if (*s >= '5') 899 ++part[ipart]; 900 while (isDIGIT(*s)) 901 ++s; 902 /* warn of loss of precision? */ 903 break; 904 } 905 } 906 --expextra; 907 part[ipart] = part[ipart] * 10 + (*s++ - '0'); 908 } 909 } 910 911 /* combine components of mantissa */ 912 for (i = 0; i <= ipart; ++i) 913 result += S_mulexp10((NV)part[ipart - i], 914 i ? offcount + (i - 1) * PARTSIZE : 0); 915 916 if (seendigit && (*s == 'e' || *s == 'E')) { 917 bool expnegative = 0; 918 919 ++s; 920 switch (*s) { 921 case '-': 922 expnegative = 1; 923 /* fall through */ 924 case '+': 925 ++s; 926 } 927 while (isDIGIT(*s)) 928 exponent = exponent * 10 + (*s++ - '0'); 929 if (expnegative) 930 exponent = -exponent; 931 } 932 933 /* now apply the exponent */ 934 exponent += expextra; 935 result = S_mulexp10(result, exponent); 936 937 /* now apply the sign */ 938 if (negative) 939 result = -result; 940 #endif /* USE_PERL_ATOF */ 941 *value = result; 942 return s; 943 } 944 945