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Re-establish the fp overflow detection for VAX VMS; there
[perl5.git] / numeric.c
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98994639
HS
1/* numeric.c
2 *
3 * Copyright (c) 2001, 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#include "EXTERN.h"
16#define PERL_IN_NUMERIC_C
17#include "perl.h"
18
19U32
20Perl_cast_ulong(pTHX_ NV f)
21{
22 if (f < 0.0)
23 return f < I32_MIN ? (U32) I32_MIN : (U32)(I32) f;
24 if (f < U32_MAX_P1) {
25#if CASTFLAGS & 2
26 if (f < U32_MAX_P1_HALF)
27 return (U32) f;
28 f -= U32_MAX_P1_HALF;
29 return ((U32) f) | (1 + U32_MAX >> 1);
30#else
31 return (U32) f;
32#endif
33 }
34 return f > 0 ? U32_MAX : 0 /* NaN */;
35}
36
37I32
38Perl_cast_i32(pTHX_ NV f)
39{
40 if (f < I32_MAX_P1)
41 return f < I32_MIN ? I32_MIN : (I32) f;
42 if (f < U32_MAX_P1) {
43#if CASTFLAGS & 2
44 if (f < U32_MAX_P1_HALF)
45 return (I32)(U32) f;
46 f -= U32_MAX_P1_HALF;
47 return (I32)(((U32) f) | (1 + U32_MAX >> 1));
48#else
49 return (I32)(U32) f;
50#endif
51 }
52 return f > 0 ? (I32)U32_MAX : 0 /* NaN */;
53}
54
55IV
56Perl_cast_iv(pTHX_ NV f)
57{
58 if (f < IV_MAX_P1)
59 return f < IV_MIN ? IV_MIN : (IV) f;
60 if (f < UV_MAX_P1) {
61#if CASTFLAGS & 2
62 /* For future flexibility allowing for sizeof(UV) >= sizeof(IV) */
63 if (f < UV_MAX_P1_HALF)
64 return (IV)(UV) f;
65 f -= UV_MAX_P1_HALF;
66 return (IV)(((UV) f) | (1 + UV_MAX >> 1));
67#else
68 return (IV)(UV) f;
69#endif
70 }
71 return f > 0 ? (IV)UV_MAX : 0 /* NaN */;
72}
73
74UV
75Perl_cast_uv(pTHX_ NV f)
76{
77 if (f < 0.0)
78 return f < IV_MIN ? (UV) IV_MIN : (UV)(IV) f;
79 if (f < UV_MAX_P1) {
80#if CASTFLAGS & 2
81 if (f < UV_MAX_P1_HALF)
82 return (UV) f;
83 f -= UV_MAX_P1_HALF;
84 return ((UV) f) | (1 + UV_MAX >> 1);
85#else
86 return (UV) f;
87#endif
88 }
89 return f > 0 ? UV_MAX : 0 /* NaN */;
90}
91
92#if defined(HUGE_VAL) || (defined(USE_LONG_DOUBLE) && defined(HUGE_VALL))
93/*
94 * This hack is to force load of "huge" support from libm.a
95 * So it is in perl for (say) POSIX to use.
96 * Needed for SunOS with Sun's 'acc' for example.
97 */
98NV
99Perl_huge(void)
100{
101# if defined(USE_LONG_DOUBLE) && defined(HUGE_VALL)
102 return HUGE_VALL;
103# endif
104 return HUGE_VAL;
105}
106#endif
107
108NV
109Perl_scan_bin(pTHX_ char *start, STRLEN len, STRLEN *retlen)
110{
111 register char *s = start;
112 register NV rnv = 0.0;
113 register UV ruv = 0;
114 register bool seenb = FALSE;
115 register bool overflowed = FALSE;
116
117 for (; len-- && *s; s++) {
118 if (!(*s == '0' || *s == '1')) {
119 if (*s == '_' && len && *retlen
120 && (s[1] == '0' || s[1] == '1'))
121 {
122 --len;
123 ++s;
124 }
125 else if (seenb == FALSE && *s == 'b' && ruv == 0) {
126 /* Disallow 0bbb0b0bbb... */
127 seenb = TRUE;
128 continue;
129 }
130 else {
131 if (ckWARN(WARN_DIGIT))
132 Perl_warner(aTHX_ WARN_DIGIT,
133 "Illegal binary digit '%c' ignored", *s);
134 break;
135 }
136 }
137 if (!overflowed) {
138 register UV xuv = ruv << 1;
139
140 if ((xuv >> 1) != ruv) {
141 overflowed = TRUE;
142 rnv = (NV) ruv;
143 if (ckWARN_d(WARN_OVERFLOW))
144 Perl_warner(aTHX_ WARN_OVERFLOW,
145 "Integer overflow in binary number");
146 }
147 else
148 ruv = xuv | (*s - '0');
149 }
150 if (overflowed) {
151 rnv *= 2;
152 /* If an NV has not enough bits in its mantissa to
153 * represent an UV this summing of small low-order numbers
154 * is a waste of time (because the NV cannot preserve
155 * the low-order bits anyway): we could just remember when
156 * did we overflow and in the end just multiply rnv by the
157 * right amount. */
158 rnv += (*s - '0');
159 }
160 }
161 if (!overflowed)
162 rnv = (NV) ruv;
163 if ( ( overflowed && rnv > 4294967295.0)
164#if UVSIZE > 4
165 || (!overflowed && ruv > 0xffffffff )
166#endif
167 ) {
168 if (ckWARN(WARN_PORTABLE))
169 Perl_warner(aTHX_ WARN_PORTABLE,
170 "Binary number > 0b11111111111111111111111111111111 non-portable");
171 }
172 *retlen = s - start;
173 return rnv;
174}
175
176NV
177Perl_scan_oct(pTHX_ char *start, STRLEN len, STRLEN *retlen)
178{
179 register char *s = start;
180 register NV rnv = 0.0;
181 register UV ruv = 0;
182 register bool overflowed = FALSE;
183
184 for (; len-- && *s; s++) {
185 if (!(*s >= '0' && *s <= '7')) {
186 if (*s == '_' && len && *retlen
187 && (s[1] >= '0' && s[1] <= '7'))
188 {
189 --len;
190 ++s;
191 }
192 else {
193 /* Allow \octal to work the DWIM way (that is, stop scanning
194 * as soon as non-octal characters are seen, complain only iff
195 * someone seems to want to use the digits eight and nine). */
196 if (*s == '8' || *s == '9') {
197 if (ckWARN(WARN_DIGIT))
198 Perl_warner(aTHX_ WARN_DIGIT,
199 "Illegal octal digit '%c' ignored", *s);
200 }
201 break;
202 }
203 }
204 if (!overflowed) {
205 register UV xuv = ruv << 3;
206
207 if ((xuv >> 3) != ruv) {
208 overflowed = TRUE;
209 rnv = (NV) ruv;
210 if (ckWARN_d(WARN_OVERFLOW))
211 Perl_warner(aTHX_ WARN_OVERFLOW,
212 "Integer overflow in octal number");
213 }
214 else
215 ruv = xuv | (*s - '0');
216 }
217 if (overflowed) {
218 rnv *= 8.0;
219 /* If an NV has not enough bits in its mantissa to
220 * represent an UV this summing of small low-order numbers
221 * is a waste of time (because the NV cannot preserve
222 * the low-order bits anyway): we could just remember when
223 * did we overflow and in the end just multiply rnv by the
224 * right amount of 8-tuples. */
225 rnv += (NV)(*s - '0');
226 }
227 }
228 if (!overflowed)
229 rnv = (NV) ruv;
230 if ( ( overflowed && rnv > 4294967295.0)
231#if UVSIZE > 4
232 || (!overflowed && ruv > 0xffffffff )
233#endif
234 ) {
235 if (ckWARN(WARN_PORTABLE))
236 Perl_warner(aTHX_ WARN_PORTABLE,
237 "Octal number > 037777777777 non-portable");
238 }
239 *retlen = s - start;
240 return rnv;
241}
242
243NV
244Perl_scan_hex(pTHX_ char *start, STRLEN len, STRLEN *retlen)
245{
246 register char *s = start;
247 register NV rnv = 0.0;
248 register UV ruv = 0;
249 register bool overflowed = FALSE;
250 char *hexdigit;
251
252 if (len > 2) {
253 if (s[0] == 'x') {
254 s++;
255 len--;
256 }
257 else if (len > 3 && s[0] == '0' && s[1] == 'x') {
258 s+=2;
259 len-=2;
260 }
261 }
262
263 for (; len-- && *s; s++) {
264 hexdigit = strchr((char *) PL_hexdigit, *s);
265 if (!hexdigit) {
266 if (*s == '_' && len && *retlen && s[1]
267 && (hexdigit = strchr((char *) PL_hexdigit, s[1])))
268 {
269 --len;
270 ++s;
271 }
272 else {
273 if (ckWARN(WARN_DIGIT))
274 Perl_warner(aTHX_ WARN_DIGIT,
275 "Illegal hexadecimal digit '%c' ignored", *s);
276 break;
277 }
278 }
279 if (!overflowed) {
280 register UV xuv = ruv << 4;
281
282 if ((xuv >> 4) != ruv) {
283 overflowed = TRUE;
284 rnv = (NV) ruv;
285 if (ckWARN_d(WARN_OVERFLOW))
286 Perl_warner(aTHX_ WARN_OVERFLOW,
287 "Integer overflow in hexadecimal number");
288 }
289 else
290 ruv = xuv | ((hexdigit - PL_hexdigit) & 15);
291 }
292 if (overflowed) {
293 rnv *= 16.0;
294 /* If an NV has not enough bits in its mantissa to
295 * represent an UV this summing of small low-order numbers
296 * is a waste of time (because the NV cannot preserve
297 * the low-order bits anyway): we could just remember when
298 * did we overflow and in the end just multiply rnv by the
299 * right amount of 16-tuples. */
300 rnv += (NV)((hexdigit - PL_hexdigit) & 15);
301 }
302 }
303 if (!overflowed)
304 rnv = (NV) ruv;
305 if ( ( overflowed && rnv > 4294967295.0)
306#if UVSIZE > 4
307 || (!overflowed && ruv > 0xffffffff )
308#endif
309 ) {
310 if (ckWARN(WARN_PORTABLE))
311 Perl_warner(aTHX_ WARN_PORTABLE,
312 "Hexadecimal number > 0xffffffff non-portable");
313 }
314 *retlen = s - start;
315 return rnv;
316}
317
318/*
319=for apidoc grok_numeric_radix
320
321Scan and skip for a numeric decimal separator (radix).
322
323=cut
324 */
325bool
326Perl_grok_numeric_radix(pTHX_ const char **sp, const char *send)
327{
328#ifdef USE_LOCALE_NUMERIC
329 if (PL_numeric_radix_sv && IN_LOCALE) {
330 STRLEN len;
331 char* radix = SvPV(PL_numeric_radix_sv, len);
332 if (*sp + len <= send && memEQ(*sp, radix, len)) {
333 *sp += len;
334 return TRUE;
335 }
336 }
337 /* always try "." if numeric radix didn't match because
338 * we may have data from different locales mixed */
339#endif
340 if (*sp < send && **sp == '.') {
341 ++*sp;
342 return TRUE;
343 }
344 return FALSE;
345}
346
347/*
348=for apidoc grok_number
349
350Recognise (or not) a number. The type of the number is returned
351(0 if unrecognised), otherwise it is a bit-ORed combination of
352IS_NUMBER_IN_UV, IS_NUMBER_GREATER_THAN_UV_MAX, IS_NUMBER_NOT_INT,
aa8b85de 353IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUMBER_NAN (defined in perl.h).
60939fb8
NC
354
355If the value of the number can fit an in UV, it is returned in the *valuep
356IS_NUMBER_IN_UV will be set to indicate that *valuep is valid, IS_NUMBER_IN_UV
357will never be set unless *valuep is valid, but *valuep may have been assigned
358to during processing even though IS_NUMBER_IN_UV is not set on return.
359If valuep is NULL, IS_NUMBER_IN_UV will be set for the same cases as when
360valuep is non-NULL, but no actual assignment (or SEGV) will occur.
361
362IS_NUMBER_NOT_INT will be set with IS_NUMBER_IN_UV if trailing decimals were
363seen (in which case *valuep gives the true value truncated to an integer), and
364IS_NUMBER_NEG if the number is negative (in which case *valuep holds the
365absolute value). IS_NUMBER_IN_UV is not set if e notation was used or the
366number is larger than a UV.
98994639
HS
367
368=cut
369 */
370int
371Perl_grok_number(pTHX_ const char *pv, STRLEN len, UV *valuep)
372{
60939fb8
NC
373 const char *s = pv;
374 const char *send = pv + len;
375 const UV max_div_10 = UV_MAX / 10;
376 const char max_mod_10 = UV_MAX % 10;
377 int numtype = 0;
378 int sawinf = 0;
aa8b85de 379 int sawnan = 0;
60939fb8
NC
380
381 while (s < send && isSPACE(*s))
382 s++;
383 if (s == send) {
384 return 0;
385 } else if (*s == '-') {
386 s++;
387 numtype = IS_NUMBER_NEG;
388 }
389 else if (*s == '+')
390 s++;
391
392 if (s == send)
393 return 0;
394
395 /* next must be digit or the radix separator or beginning of infinity */
396 if (isDIGIT(*s)) {
397 /* UVs are at least 32 bits, so the first 9 decimal digits cannot
398 overflow. */
399 UV value = *s - '0';
400 /* This construction seems to be more optimiser friendly.
401 (without it gcc does the isDIGIT test and the *s - '0' separately)
402 With it gcc on arm is managing 6 instructions (6 cycles) per digit.
403 In theory the optimiser could deduce how far to unroll the loop
404 before checking for overflow. */
58bb9ec3
NC
405 if (++s < send) {
406 int digit = *s - '0';
60939fb8
NC
407 if (digit >= 0 && digit <= 9) {
408 value = value * 10 + digit;
58bb9ec3
NC
409 if (++s < send) {
410 digit = *s - '0';
60939fb8
NC
411 if (digit >= 0 && digit <= 9) {
412 value = value * 10 + digit;
58bb9ec3
NC
413 if (++s < send) {
414 digit = *s - '0';
60939fb8
NC
415 if (digit >= 0 && digit <= 9) {
416 value = value * 10 + digit;
58bb9ec3
NC
417 if (++s < send) {
418 digit = *s - '0';
60939fb8
NC
419 if (digit >= 0 && digit <= 9) {
420 value = value * 10 + digit;
58bb9ec3
NC
421 if (++s < send) {
422 digit = *s - '0';
60939fb8
NC
423 if (digit >= 0 && digit <= 9) {
424 value = value * 10 + digit;
58bb9ec3
NC
425 if (++s < send) {
426 digit = *s - '0';
60939fb8
NC
427 if (digit >= 0 && digit <= 9) {
428 value = value * 10 + digit;
58bb9ec3
NC
429 if (++s < send) {
430 digit = *s - '0';
60939fb8
NC
431 if (digit >= 0 && digit <= 9) {
432 value = value * 10 + digit;
58bb9ec3
NC
433 if (++s < send) {
434 digit = *s - '0';
60939fb8
NC
435 if (digit >= 0 && digit <= 9) {
436 value = value * 10 + digit;
58bb9ec3 437 if (++s < send) {
60939fb8
NC
438 /* Now got 9 digits, so need to check
439 each time for overflow. */
58bb9ec3 440 digit = *s - '0';
60939fb8
NC
441 while (digit >= 0 && digit <= 9
442 && (value < max_div_10
443 || (value == max_div_10
444 && digit <= max_mod_10))) {
445 value = value * 10 + digit;
58bb9ec3
NC
446 if (++s < send)
447 digit = *s - '0';
60939fb8
NC
448 else
449 break;
450 }
451 if (digit >= 0 && digit <= 9
51bd16da 452 && (s < send)) {
60939fb8
NC
453 /* value overflowed.
454 skip the remaining digits, don't
455 worry about setting *valuep. */
456 do {
457 s++;
458 } while (s < send && isDIGIT(*s));
459 numtype |=
460 IS_NUMBER_GREATER_THAN_UV_MAX;
461 goto skip_value;
462 }
463 }
464 }
98994639 465 }
60939fb8
NC
466 }
467 }
468 }
469 }
470 }
471 }
472 }
473 }
474 }
475 }
476 }
98994639 477 }
60939fb8 478 }
98994639 479 }
60939fb8
NC
480 numtype |= IS_NUMBER_IN_UV;
481 if (valuep)
482 *valuep = value;
483
484 skip_value:
485 if (GROK_NUMERIC_RADIX(&s, send)) {
486 numtype |= IS_NUMBER_NOT_INT;
487 while (s < send && isDIGIT(*s)) /* optional digits after the radix */
488 s++;
98994639 489 }
60939fb8
NC
490 }
491 else if (GROK_NUMERIC_RADIX(&s, send)) {
492 numtype |= IS_NUMBER_NOT_INT | IS_NUMBER_IN_UV; /* valuep assigned below */
493 /* no digits before the radix means we need digits after it */
494 if (s < send && isDIGIT(*s)) {
495 do {
496 s++;
497 } while (s < send && isDIGIT(*s));
498 if (valuep) {
499 /* integer approximation is valid - it's 0. */
500 *valuep = 0;
501 }
98994639 502 }
60939fb8
NC
503 else
504 return 0;
505 } else if (*s == 'I' || *s == 'i') {
506 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
507 s++; if (s == send || (*s != 'F' && *s != 'f')) return 0;
508 s++; if (s < send && (*s == 'I' || *s == 'i')) {
509 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
510 s++; if (s == send || (*s != 'I' && *s != 'i')) return 0;
511 s++; if (s == send || (*s != 'T' && *s != 't')) return 0;
512 s++; if (s == send || (*s != 'Y' && *s != 'y')) return 0;
513 s++;
98994639 514 }
60939fb8 515 sawinf = 1;
aa8b85de
JH
516 } else if (*s == 'N' || *s == 'n') {
517 /* XXX TODO: There are signaling NaNs and quiet NaNs. */
518 s++; if (s == send || (*s != 'A' && *s != 'a')) return 0;
519 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
520 s++;
521 sawnan = 1;
522 } else
98994639 523 return 0;
60939fb8
NC
524
525 if (sawinf) {
526 numtype &= IS_NUMBER_NEG; /* Keep track of sign */
527 numtype |= IS_NUMBER_INFINITY | IS_NUMBER_NOT_INT;
aa8b85de
JH
528 } else if (sawnan) {
529 numtype &= IS_NUMBER_NEG; /* Keep track of sign */
530 numtype |= IS_NUMBER_NAN | IS_NUMBER_NOT_INT;
60939fb8
NC
531 } else if (s < send) {
532 /* we can have an optional exponent part */
533 if (*s == 'e' || *s == 'E') {
534 /* The only flag we keep is sign. Blow away any "it's UV" */
535 numtype &= IS_NUMBER_NEG;
536 numtype |= IS_NUMBER_NOT_INT;
537 s++;
538 if (s < send && (*s == '-' || *s == '+'))
539 s++;
540 if (s < send && isDIGIT(*s)) {
541 do {
542 s++;
543 } while (s < send && isDIGIT(*s));
544 }
545 else
546 return 0;
547 }
548 }
549 while (s < send && isSPACE(*s))
550 s++;
551 if (s >= send)
aa8b85de 552 return numtype;
60939fb8
NC
553 if (len == 10 && memEQ(pv, "0 but true", 10)) {
554 if (valuep)
555 *valuep = 0;
556 return IS_NUMBER_IN_UV;
557 }
558 return 0;
98994639
HS
559}
560
561NV
562S_mulexp10(NV value, I32 exponent)
563{
564 NV result = 1.0;
565 NV power = 10.0;
566 bool negative = 0;
567 I32 bit;
568
569 if (exponent == 0)
570 return value;
571 else if (exponent < 0) {
572 negative = 1;
573 exponent = -exponent;
574 }
67597c89
JH
575 /* Avoid %SYSTEM-F-FLTOVF_F sans VAXC$ESTABLISH.
576 * In VAX VMS we by default use the D_FLOAT double format,
577 * and that format does not have *easy* capabilities [1] for
578 * overflowing doubles 'silently' as IEEE fp does. Therefore we
579 * need to detect early whether we would overflow (this is
580 * the behaviour of the native string-to-float conversion routines,
581 * and therefore the behaviour of native applications, too.)
582 *
583 * [1] VAXC$EXTABLISH is the capability but it is basically a signal
584 * handler setup routine, and one cannot return from a fp exception
585 * handler and except much anything useful. */
586#if defined(VMS) && !defined(__IEEE_FP)
587# if defined(__DECC_VER) && __DECC_VER <= 50390006
588 /* __F_FLT_MAX_10_EXP - 5 == 33 */
589 if (!negative &&
590 (log10(value) + exponent) >= (__F_FLT_MAX_10_EXP - 5))
591 return NV_MAX;
592# endif
593#endif
98994639
HS
594 for (bit = 1; exponent; bit <<= 1) {
595 if (exponent & bit) {
596 exponent ^= bit;
597 result *= power;
598 }
7014c407 599 /* Floating point exceptions are supposed to be turned off. */
98994639
HS
600 power *= power;
601 }
602 return negative ? value / result : value * result;
603}
604
605NV
606Perl_my_atof(pTHX_ const char* s)
607{
608 NV x = 0.0;
609#ifdef USE_LOCALE_NUMERIC
610 if (PL_numeric_local && IN_LOCALE) {
611 NV y;
612
613 /* Scan the number twice; once using locale and once without;
614 * choose the larger result (in absolute value). */
615 Perl_atof2(aTHX_ s, &x);
616 SET_NUMERIC_STANDARD();
617 Perl_atof2(aTHX_ s, &y);
618 SET_NUMERIC_LOCAL();
619 if ((y < 0.0 && y < x) || (y > 0.0 && y > x))
620 return y;
621 }
622 else
623 Perl_atof2(aTHX_ s, &x);
624#else
625 Perl_atof2(aTHX_ s, &x);
626#endif
627 return x;
628}
629
630char*
631Perl_my_atof2(pTHX_ const char* orig, NV* value)
632{
633 NV result = 0.0;
634 bool negative = 0;
635 char* s = (char*)orig;
636 char* send = s + strlen(orig) - 1;
637 bool seendigit = 0;
638 I32 expextra = 0;
639 I32 exponent = 0;
640 I32 i;
641/* this is arbitrary */
642#define PARTLIM 6
643/* we want the largest integers we can usefully use */
644#if defined(HAS_QUAD) && defined(USE_64_BIT_INT)
645# define PARTSIZE ((int)TYPE_DIGITS(U64)-1)
646 U64 part[PARTLIM];
647#else
648# define PARTSIZE ((int)TYPE_DIGITS(U32)-1)
649 U32 part[PARTLIM];
650#endif
651 I32 ipart = 0; /* index into part[] */
652 I32 offcount; /* number of digits in least significant part */
653
96a05aee
HS
654 /* leading whitespace */
655 while (isSPACE(*s))
656 ++s;
657
98994639
HS
658 /* sign */
659 switch (*s) {
660 case '-':
661 negative = 1;
662 /* fall through */
663 case '+':
664 ++s;
665 }
666
667 part[0] = offcount = 0;
668 if (isDIGIT(*s)) {
669 seendigit = 1; /* get this over with */
670
671 /* skip leading zeros */
672 while (*s == '0')
673 ++s;
674 }
675
676 /* integer digits */
677 while (isDIGIT(*s)) {
678 if (++offcount > PARTSIZE) {
679 if (++ipart < PARTLIM) {
680 part[ipart] = 0;
681 offcount = 1; /* ++0 */
682 }
683 else {
684 /* limits of precision reached */
685 --ipart;
686 --offcount;
687 if (*s >= '5')
688 ++part[ipart];
689 while (isDIGIT(*s)) {
690 ++expextra;
691 ++s;
692 }
693 /* warn of loss of precision? */
694 break;
695 }
696 }
697 part[ipart] = part[ipart] * 10 + (*s++ - '0');
698 }
699
700 /* decimal point */
701 if (GROK_NUMERIC_RADIX((const char **)&s, send)) {
702 if (isDIGIT(*s))
703 seendigit = 1; /* get this over with */
704
705 /* decimal digits */
706 while (isDIGIT(*s)) {
707 if (++offcount > PARTSIZE) {
708 if (++ipart < PARTLIM) {
709 part[ipart] = 0;
710 offcount = 1; /* ++0 */
711 }
712 else {
713 /* limits of precision reached */
714 --ipart;
715 --offcount;
716 if (*s >= '5')
717 ++part[ipart];
718 while (isDIGIT(*s))
719 ++s;
720 /* warn of loss of precision? */
721 break;
722 }
723 }
724 --expextra;
725 part[ipart] = part[ipart] * 10 + (*s++ - '0');
726 }
727 }
728
729 /* combine components of mantissa */
730 for (i = 0; i <= ipart; ++i)
731 result += S_mulexp10((NV)part[ipart - i],
732 i ? offcount + (i - 1) * PARTSIZE : 0);
733
734 if (seendigit && (*s == 'e' || *s == 'E')) {
735 bool expnegative = 0;
736
737 ++s;
738 switch (*s) {
739 case '-':
740 expnegative = 1;
741 /* fall through */
742 case '+':
743 ++s;
744 }
745 while (isDIGIT(*s))
746 exponent = exponent * 10 + (*s++ - '0');
747 if (expnegative)
748 exponent = -exponent;
749 }
750
751 /* now apply the exponent */
752 exponent += expextra;
753 result = S_mulexp10(result, exponent);
754
755 /* now apply the sign */
756 if (negative)
757 result = -result;
758 *value = result;
759 return s;
760}
761