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98994639
HS
1/* numeric.c
2 *
663f364b 3 * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
1129b882 4 * 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
98994639
HS
5 *
6 * You may distribute under the terms of either the GNU General Public
7 * License or the Artistic License, as specified in the README file.
8 *
9 */
10
11/*
4ac71550
TC
12 * "That only makes eleven (plus one mislaid) and not fourteen,
13 * unless wizards count differently to other people." --Beorn
14 *
15 * [p.115 of _The Hobbit_: "Queer Lodgings"]
98994639
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16 */
17
ccfc67b7
JH
18/*
19=head1 Numeric functions
166f8a29 20
7fefc6c1
KW
21=cut
22
166f8a29
DM
23This file contains all the stuff needed by perl for manipulating numeric
24values, including such things as replacements for the OS's atof() function
25
ccfc67b7
JH
26*/
27
98994639
HS
28#include "EXTERN.h"
29#define PERL_IN_NUMERIC_C
30#include "perl.h"
31
32U32
ddeaf645 33Perl_cast_ulong(NV f)
98994639
HS
34{
35 if (f < 0.0)
36 return f < I32_MIN ? (U32) I32_MIN : (U32)(I32) f;
37 if (f < U32_MAX_P1) {
38#if CASTFLAGS & 2
39 if (f < U32_MAX_P1_HALF)
40 return (U32) f;
41 f -= U32_MAX_P1_HALF;
071db91b 42 return ((U32) f) | (1 + (U32_MAX >> 1));
98994639
HS
43#else
44 return (U32) f;
45#endif
46 }
47 return f > 0 ? U32_MAX : 0 /* NaN */;
48}
49
50I32
ddeaf645 51Perl_cast_i32(NV f)
98994639
HS
52{
53 if (f < I32_MAX_P1)
54 return f < I32_MIN ? I32_MIN : (I32) f;
55 if (f < U32_MAX_P1) {
56#if CASTFLAGS & 2
57 if (f < U32_MAX_P1_HALF)
58 return (I32)(U32) f;
59 f -= U32_MAX_P1_HALF;
071db91b 60 return (I32)(((U32) f) | (1 + (U32_MAX >> 1)));
98994639
HS
61#else
62 return (I32)(U32) f;
63#endif
64 }
65 return f > 0 ? (I32)U32_MAX : 0 /* NaN */;
66}
67
68IV
ddeaf645 69Perl_cast_iv(NV f)
98994639
HS
70{
71 if (f < IV_MAX_P1)
72 return f < IV_MIN ? IV_MIN : (IV) f;
73 if (f < UV_MAX_P1) {
74#if CASTFLAGS & 2
75 /* For future flexibility allowing for sizeof(UV) >= sizeof(IV) */
76 if (f < UV_MAX_P1_HALF)
77 return (IV)(UV) f;
78 f -= UV_MAX_P1_HALF;
071db91b 79 return (IV)(((UV) f) | (1 + (UV_MAX >> 1)));
98994639
HS
80#else
81 return (IV)(UV) f;
82#endif
83 }
84 return f > 0 ? (IV)UV_MAX : 0 /* NaN */;
85}
86
87UV
ddeaf645 88Perl_cast_uv(NV f)
98994639
HS
89{
90 if (f < 0.0)
91 return f < IV_MIN ? (UV) IV_MIN : (UV)(IV) f;
92 if (f < UV_MAX_P1) {
93#if CASTFLAGS & 2
94 if (f < UV_MAX_P1_HALF)
95 return (UV) f;
96 f -= UV_MAX_P1_HALF;
071db91b 97 return ((UV) f) | (1 + (UV_MAX >> 1));
98994639
HS
98#else
99 return (UV) f;
100#endif
101 }
102 return f > 0 ? UV_MAX : 0 /* NaN */;
103}
104
53305cf1
NC
105/*
106=for apidoc grok_bin
98994639 107
53305cf1
NC
108converts a string representing a binary number to numeric form.
109
2d7f6611 110On entry C<start> and C<*len> give the string to scan, C<*flags> gives
796b6530 111conversion flags, and C<result> should be C<NULL> or a pointer to an NV.
53305cf1 112The scan stops at the end of the string, or the first invalid character.
2d7f6611 113Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in C<*flags>, encountering an
7b667b5f 114invalid character will also trigger a warning.
2d7f6611
KW
115On return C<*len> is set to the length of the scanned string,
116and C<*flags> gives output flags.
53305cf1 117
7fc63493 118If the value is <= C<UV_MAX> it is returned as a UV, the output flags are clear,
796b6530
KW
119and nothing is written to C<*result>. If the value is > C<UV_MAX>, C<grok_bin>
120returns C<UV_MAX>, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
2d7f6611 121and writes the value to C<*result> (or the value is discarded if C<result>
53305cf1
NC
122is NULL).
123
796b6530 124The binary number may optionally be prefixed with C<"0b"> or C<"b"> unless
2d7f6611
KW
125C<PERL_SCAN_DISALLOW_PREFIX> is set in C<*flags> on entry. If
126C<PERL_SCAN_ALLOW_UNDERSCORES> is set in C<*flags> then the binary
796b6530 127number may use C<"_"> characters to separate digits.
53305cf1
NC
128
129=cut
02470786
KW
130
131Not documented yet because experimental is C<PERL_SCAN_SILENT_NON_PORTABLE
132which suppresses any message for non-portable numbers that are still valid
133on this platform.
53305cf1
NC
134 */
135
136UV
7918f24d
NC
137Perl_grok_bin(pTHX_ const char *start, STRLEN *len_p, I32 *flags, NV *result)
138{
53305cf1
NC
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;
f2338a2e 145 const bool allow_underscores = cBOOL(*flags & PERL_SCAN_ALLOW_UNDERSCORES);
53305cf1 146 bool overflowed = FALSE;
7fc63493 147 char bit;
53305cf1 148
7918f24d
NC
149 PERL_ARGS_ASSERT_GROK_BIN;
150
a4c04bdc
NC
151 if (!(*flags & PERL_SCAN_DISALLOW_PREFIX)) {
152 /* strip off leading b or 0b.
153 for compatibility silently suffer "b" and "0b" as valid binary
154 numbers. */
155 if (len >= 1) {
305b8651 156 if (isALPHA_FOLD_EQ(s[0], 'b')) {
a4c04bdc
NC
157 s++;
158 len--;
159 }
305b8651 160 else if (len >= 2 && s[0] == '0' && (isALPHA_FOLD_EQ(s[1], 'b'))) {
a4c04bdc
NC
161 s+=2;
162 len-=2;
163 }
164 }
53305cf1
NC
165 }
166
7fc63493 167 for (; len-- && (bit = *s); s++) {
53305cf1
NC
168 if (bit == '0' || bit == '1') {
169 /* Write it in this wonky order with a goto to attempt to get the
170 compiler to make the common case integer-only loop pretty tight.
171 With gcc seems to be much straighter code than old scan_bin. */
172 redo:
173 if (!overflowed) {
174 if (value <= max_div_2) {
175 value = (value << 1) | (bit - '0');
176 continue;
177 }
178 /* Bah. We're just overflowed. */
dcbac5bb 179 /* diag_listed_as: Integer overflow in %s number */
9b387841
NC
180 Perl_ck_warner_d(aTHX_ packWARN(WARN_OVERFLOW),
181 "Integer overflow in binary number");
53305cf1
NC
182 overflowed = TRUE;
183 value_nv = (NV) value;
184 }
185 value_nv *= 2.0;
98994639 186 /* If an NV has not enough bits in its mantissa to
d1be9408 187 * represent a UV this summing of small low-order numbers
98994639
HS
188 * is a waste of time (because the NV cannot preserve
189 * the low-order bits anyway): we could just remember when
53305cf1 190 * did we overflow and in the end just multiply value_nv by the
98994639 191 * right amount. */
53305cf1
NC
192 value_nv += (NV)(bit - '0');
193 continue;
194 }
195 if (bit == '_' && len && allow_underscores && (bit = s[1])
196 && (bit == '0' || bit == '1'))
98994639
HS
197 {
198 --len;
199 ++s;
53305cf1 200 goto redo;
98994639 201 }
a2a5de95
NC
202 if (!(*flags & PERL_SCAN_SILENT_ILLDIGIT))
203 Perl_ck_warner(aTHX_ packWARN(WARN_DIGIT),
204 "Illegal binary digit '%c' ignored", *s);
53305cf1 205 break;
98994639 206 }
19c1206d 207
53305cf1 208 if ( ( overflowed && value_nv > 4294967295.0)
98994639 209#if UVSIZE > 4
02470786
KW
210 || (!overflowed && value > 0xffffffff
211 && ! (*flags & PERL_SCAN_SILENT_NON_PORTABLE))
98994639
HS
212#endif
213 ) {
a2a5de95
NC
214 Perl_ck_warner(aTHX_ packWARN(WARN_PORTABLE),
215 "Binary number > 0b11111111111111111111111111111111 non-portable");
53305cf1
NC
216 }
217 *len_p = s - start;
218 if (!overflowed) {
219 *flags = 0;
220 return value;
98994639 221 }
53305cf1
NC
222 *flags = PERL_SCAN_GREATER_THAN_UV_MAX;
223 if (result)
224 *result = value_nv;
225 return UV_MAX;
98994639
HS
226}
227
53305cf1
NC
228/*
229=for apidoc grok_hex
230
231converts a string representing a hex number to numeric form.
232
2d7f6611 233On entry C<start> and C<*len_p> give the string to scan, C<*flags> gives
796b6530 234conversion flags, and C<result> should be C<NULL> or a pointer to an NV.
7b667b5f 235The scan stops at the end of the string, or the first invalid character.
2d7f6611 236Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in C<*flags>, encountering an
7b667b5f 237invalid character will also trigger a warning.
2d7f6611
KW
238On return C<*len> is set to the length of the scanned string,
239and C<*flags> gives output flags.
53305cf1 240
796b6530
KW
241If the value is <= C<UV_MAX> it is returned as a UV, the output flags are clear,
242and nothing is written to C<*result>. If the value is > C<UV_MAX>, C<grok_hex>
243returns C<UV_MAX>, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
2d7f6611 244and writes the value to C<*result> (or the value is discarded if C<result>
796b6530 245is C<NULL>).
53305cf1 246
796b6530 247The hex number may optionally be prefixed with C<"0x"> or C<"x"> unless
2d7f6611
KW
248C<PERL_SCAN_DISALLOW_PREFIX> is set in C<*flags> on entry. If
249C<PERL_SCAN_ALLOW_UNDERSCORES> is set in C<*flags> then the hex
796b6530 250number may use C<"_"> characters to separate digits.
53305cf1
NC
251
252=cut
02470786
KW
253
254Not documented yet because experimental is C<PERL_SCAN_SILENT_NON_PORTABLE
baf48926 255which suppresses any message for non-portable numbers, but which are valid
02470786 256on this platform.
53305cf1
NC
257 */
258
259UV
7918f24d
NC
260Perl_grok_hex(pTHX_ const char *start, STRLEN *len_p, I32 *flags, NV *result)
261{
53305cf1
NC
262 const char *s = start;
263 STRLEN len = *len_p;
264 UV value = 0;
265 NV value_nv = 0;
53305cf1 266 const UV max_div_16 = UV_MAX / 16;
f2338a2e 267 const bool allow_underscores = cBOOL(*flags & PERL_SCAN_ALLOW_UNDERSCORES);
53305cf1 268 bool overflowed = FALSE;
98994639 269
7918f24d
NC
270 PERL_ARGS_ASSERT_GROK_HEX;
271
a4c04bdc
NC
272 if (!(*flags & PERL_SCAN_DISALLOW_PREFIX)) {
273 /* strip off leading x or 0x.
274 for compatibility silently suffer "x" and "0x" as valid hex numbers.
275 */
276 if (len >= 1) {
305b8651 277 if (isALPHA_FOLD_EQ(s[0], 'x')) {
a4c04bdc
NC
278 s++;
279 len--;
280 }
305b8651 281 else if (len >= 2 && s[0] == '0' && (isALPHA_FOLD_EQ(s[1], 'x'))) {
a4c04bdc
NC
282 s+=2;
283 len-=2;
284 }
285 }
98994639
HS
286 }
287
288 for (; len-- && *s; s++) {
626ef089 289 if (isXDIGIT(*s)) {
53305cf1
NC
290 /* Write it in this wonky order with a goto to attempt to get the
291 compiler to make the common case integer-only loop pretty tight.
292 With gcc seems to be much straighter code than old scan_hex. */
293 redo:
294 if (!overflowed) {
295 if (value <= max_div_16) {
626ef089 296 value = (value << 4) | XDIGIT_VALUE(*s);
53305cf1
NC
297 continue;
298 }
299 /* Bah. We're just overflowed. */
dcbac5bb 300 /* diag_listed_as: Integer overflow in %s number */
9b387841
NC
301 Perl_ck_warner_d(aTHX_ packWARN(WARN_OVERFLOW),
302 "Integer overflow in hexadecimal number");
53305cf1
NC
303 overflowed = TRUE;
304 value_nv = (NV) value;
305 }
306 value_nv *= 16.0;
307 /* If an NV has not enough bits in its mantissa to
d1be9408 308 * represent a UV this summing of small low-order numbers
53305cf1
NC
309 * is a waste of time (because the NV cannot preserve
310 * the low-order bits anyway): we could just remember when
311 * did we overflow and in the end just multiply value_nv by the
312 * right amount of 16-tuples. */
626ef089 313 value_nv += (NV) XDIGIT_VALUE(*s);
53305cf1
NC
314 continue;
315 }
316 if (*s == '_' && len && allow_underscores && s[1]
626ef089 317 && isXDIGIT(s[1]))
98994639
HS
318 {
319 --len;
320 ++s;
53305cf1 321 goto redo;
98994639 322 }
a2a5de95
NC
323 if (!(*flags & PERL_SCAN_SILENT_ILLDIGIT))
324 Perl_ck_warner(aTHX_ packWARN(WARN_DIGIT),
53305cf1
NC
325 "Illegal hexadecimal digit '%c' ignored", *s);
326 break;
327 }
19c1206d 328
53305cf1
NC
329 if ( ( overflowed && value_nv > 4294967295.0)
330#if UVSIZE > 4
02470786
KW
331 || (!overflowed && value > 0xffffffff
332 && ! (*flags & PERL_SCAN_SILENT_NON_PORTABLE))
53305cf1
NC
333#endif
334 ) {
a2a5de95
NC
335 Perl_ck_warner(aTHX_ packWARN(WARN_PORTABLE),
336 "Hexadecimal number > 0xffffffff non-portable");
53305cf1
NC
337 }
338 *len_p = s - start;
339 if (!overflowed) {
340 *flags = 0;
341 return value;
342 }
343 *flags = PERL_SCAN_GREATER_THAN_UV_MAX;
344 if (result)
345 *result = value_nv;
346 return UV_MAX;
347}
348
349/*
350=for apidoc grok_oct
351
7b667b5f
MHM
352converts a string representing an octal number to numeric form.
353
2d7f6611 354On entry C<start> and C<*len> give the string to scan, C<*flags> gives
796b6530 355conversion flags, and C<result> should be C<NULL> or a pointer to an NV.
7b667b5f 356The scan stops at the end of the string, or the first invalid character.
2d7f6611 357Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in C<*flags>, encountering an
154bd527 3588 or 9 will also trigger a warning.
2d7f6611
KW
359On return C<*len> is set to the length of the scanned string,
360and C<*flags> gives output flags.
7b667b5f 361
796b6530
KW
362If the value is <= C<UV_MAX> it is returned as a UV, the output flags are clear,
363and nothing is written to C<*result>. If the value is > C<UV_MAX>, C<grok_oct>
364returns C<UV_MAX>, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
2d7f6611 365and writes the value to C<*result> (or the value is discarded if C<result>
796b6530 366is C<NULL>).
7b667b5f 367
2d7f6611 368If C<PERL_SCAN_ALLOW_UNDERSCORES> is set in C<*flags> then the octal
796b6530 369number may use C<"_"> characters to separate digits.
53305cf1
NC
370
371=cut
02470786 372
333ae27c
KW
373Not documented yet because experimental is C<PERL_SCAN_SILENT_NON_PORTABLE>
374which suppresses any message for non-portable numbers, but which are valid
02470786 375on this platform.
53305cf1
NC
376 */
377
378UV
7918f24d
NC
379Perl_grok_oct(pTHX_ const char *start, STRLEN *len_p, I32 *flags, NV *result)
380{
53305cf1
NC
381 const char *s = start;
382 STRLEN len = *len_p;
383 UV value = 0;
384 NV value_nv = 0;
53305cf1 385 const UV max_div_8 = UV_MAX / 8;
f2338a2e 386 const bool allow_underscores = cBOOL(*flags & PERL_SCAN_ALLOW_UNDERSCORES);
53305cf1
NC
387 bool overflowed = FALSE;
388
7918f24d
NC
389 PERL_ARGS_ASSERT_GROK_OCT;
390
53305cf1 391 for (; len-- && *s; s++) {
626ef089 392 if (isOCTAL(*s)) {
53305cf1
NC
393 /* Write it in this wonky order with a goto to attempt to get the
394 compiler to make the common case integer-only loop pretty tight.
395 */
396 redo:
397 if (!overflowed) {
398 if (value <= max_div_8) {
626ef089 399 value = (value << 3) | OCTAL_VALUE(*s);
53305cf1
NC
400 continue;
401 }
402 /* Bah. We're just overflowed. */
dcbac5bb 403 /* diag_listed_as: Integer overflow in %s number */
9b387841
NC
404 Perl_ck_warner_d(aTHX_ packWARN(WARN_OVERFLOW),
405 "Integer overflow in octal number");
53305cf1
NC
406 overflowed = TRUE;
407 value_nv = (NV) value;
408 }
409 value_nv *= 8.0;
98994639 410 /* If an NV has not enough bits in its mantissa to
d1be9408 411 * represent a UV this summing of small low-order numbers
98994639
HS
412 * is a waste of time (because the NV cannot preserve
413 * the low-order bits anyway): we could just remember when
53305cf1
NC
414 * did we overflow and in the end just multiply value_nv by the
415 * right amount of 8-tuples. */
626ef089 416 value_nv += (NV) OCTAL_VALUE(*s);
53305cf1
NC
417 continue;
418 }
626ef089
KW
419 if (*s == '_' && len && allow_underscores && isOCTAL(s[1])) {
420 --len;
421 ++s;
422 goto redo;
423 }
53305cf1 424 /* Allow \octal to work the DWIM way (that is, stop scanning
7b667b5f 425 * as soon as non-octal characters are seen, complain only if
626ef089
KW
426 * someone seems to want to use the digits eight and nine. Since we
427 * know it is not octal, then if isDIGIT, must be an 8 or 9). */
428 if (isDIGIT(*s)) {
a2a5de95
NC
429 if (!(*flags & PERL_SCAN_SILENT_ILLDIGIT))
430 Perl_ck_warner(aTHX_ packWARN(WARN_DIGIT),
431 "Illegal octal digit '%c' ignored", *s);
53305cf1
NC
432 }
433 break;
98994639 434 }
19c1206d 435
53305cf1 436 if ( ( overflowed && value_nv > 4294967295.0)
98994639 437#if UVSIZE > 4
02470786
KW
438 || (!overflowed && value > 0xffffffff
439 && ! (*flags & PERL_SCAN_SILENT_NON_PORTABLE))
98994639
HS
440#endif
441 ) {
a2a5de95
NC
442 Perl_ck_warner(aTHX_ packWARN(WARN_PORTABLE),
443 "Octal number > 037777777777 non-portable");
53305cf1
NC
444 }
445 *len_p = s - start;
446 if (!overflowed) {
447 *flags = 0;
448 return value;
98994639 449 }
53305cf1
NC
450 *flags = PERL_SCAN_GREATER_THAN_UV_MAX;
451 if (result)
452 *result = value_nv;
453 return UV_MAX;
454}
455
456/*
457=for apidoc scan_bin
458
72d33970 459For backwards compatibility. Use C<grok_bin> instead.
53305cf1
NC
460
461=for apidoc scan_hex
462
72d33970 463For backwards compatibility. Use C<grok_hex> instead.
53305cf1
NC
464
465=for apidoc scan_oct
466
72d33970 467For backwards compatibility. Use C<grok_oct> instead.
53305cf1
NC
468
469=cut
470 */
471
472NV
73d840c0 473Perl_scan_bin(pTHX_ const char *start, STRLEN len, STRLEN *retlen)
53305cf1
NC
474{
475 NV rnv;
476 I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0;
73d840c0 477 const UV ruv = grok_bin (start, &len, &flags, &rnv);
53305cf1 478
7918f24d
NC
479 PERL_ARGS_ASSERT_SCAN_BIN;
480
53305cf1
NC
481 *retlen = len;
482 return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv;
483}
484
485NV
73d840c0 486Perl_scan_oct(pTHX_ const char *start, STRLEN len, STRLEN *retlen)
53305cf1
NC
487{
488 NV rnv;
489 I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0;
73d840c0 490 const UV ruv = grok_oct (start, &len, &flags, &rnv);
53305cf1 491
7918f24d
NC
492 PERL_ARGS_ASSERT_SCAN_OCT;
493
53305cf1
NC
494 *retlen = len;
495 return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv;
496}
497
498NV
73d840c0 499Perl_scan_hex(pTHX_ const char *start, STRLEN len, STRLEN *retlen)
53305cf1
NC
500{
501 NV rnv;
502 I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0;
73d840c0 503 const UV ruv = grok_hex (start, &len, &flags, &rnv);
53305cf1 504
7918f24d
NC
505 PERL_ARGS_ASSERT_SCAN_HEX;
506
53305cf1
NC
507 *retlen = len;
508 return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv;
98994639
HS
509}
510
511/*
512=for apidoc grok_numeric_radix
513
514Scan and skip for a numeric decimal separator (radix).
515
516=cut
517 */
518bool
519Perl_grok_numeric_radix(pTHX_ const char **sp, const char *send)
520{
7918f24d
NC
521 PERL_ARGS_ASSERT_GROK_NUMERIC_RADIX;
522
7ea85fa8
KW
523#ifdef USE_LOCALE_NUMERIC
524
d6ded950 525 if (IN_LC(LC_NUMERIC)) {
f0dafd73
KW
526 STRLEN len;
527 char * radix;
528 bool matches_radix = FALSE;
67d796ae 529 DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
f0dafd73 530
a1395eaf 531 STORE_LC_NUMERIC_FORCE_TO_UNDERLYING();
f0dafd73
KW
532
533 radix = SvPV(PL_numeric_radix_sv, len);
534 radix = savepvn(radix, len);
535
21431899 536 RESTORE_LC_NUMERIC();
f0dafd73
KW
537
538 if (*sp + len <= send) {
539 matches_radix = memEQ(*sp, radix, len);
540 }
541
542 Safefree(radix);
543
544 if (matches_radix) {
545 *sp += len;
546 return TRUE;
547 }
98994639 548 }
f0dafd73 549
98994639 550#endif
7918f24d 551
f0dafd73
KW
552 /* always try "." if numeric radix didn't match because
553 * we may have data from different locales mixed */
98994639
HS
554 if (*sp < send && **sp == '.') {
555 ++*sp;
556 return TRUE;
557 }
f0dafd73 558
98994639
HS
559 return FALSE;
560}
561
569f27e5 562/*
ff4eb398
JH
563=for apidoc grok_infnan
564
796b6530 565Helper for C<grok_number()>, accepts various ways of spelling "infinity"
ff4eb398
JH
566or "not a number", and returns one of the following flag combinations:
567
5962c2f6 568 IS_NUMBER_INFINITY
ff4eb398 569 IS_NUMBER_NAN
5962c2f6 570 IS_NUMBER_INFINITY | IS_NUMBER_NEG
ff4eb398
JH
571 IS_NUMBER_NAN | IS_NUMBER_NEG
572 0
573
796b6530 574possibly |-ed with C<IS_NUMBER_TRAILING>.
b489e20f 575
796b6530 576If an infinity or a not-a-number is recognized, C<*sp> will point to
62bdc035 577one byte past the end of the recognized string. If the recognition fails,
796b6530 578zero is returned, and C<*sp> will not move.
ff4eb398
JH
579
580=cut
581*/
582
583int
3823048b 584Perl_grok_infnan(pTHX_ const char** sp, const char* send)
ff4eb398
JH
585{
586 const char* s = *sp;
587 int flags = 0;
a5dc2484 588#if defined(NV_INF) || defined(NV_NAN)
62bdc035 589 bool odh = FALSE; /* one-dot-hash: 1.#INF */
ff4eb398
JH
590
591 PERL_ARGS_ASSERT_GROK_INFNAN;
592
8c12dc63
JH
593 if (*s == '+') {
594 s++; if (s == send) return 0;
595 }
596 else if (*s == '-') {
ff4eb398
JH
597 flags |= IS_NUMBER_NEG; /* Yes, -NaN happens. Incorrect but happens. */
598 s++; if (s == send) return 0;
599 }
600
601 if (*s == '1') {
62bdc035
JH
602 /* Visual C: 1.#SNAN, -1.#QNAN, 1#INF, 1.#IND (maybe also 1.#NAN)
603 * Let's keep the dot optional. */
ff4eb398
JH
604 s++; if (s == send) return 0;
605 if (*s == '.') {
606 s++; if (s == send) return 0;
607 }
608 if (*s == '#') {
609 s++; if (s == send) return 0;
610 } else
611 return 0;
e855f543 612 odh = TRUE;
ff4eb398
JH
613 }
614
305b8651 615 if (isALPHA_FOLD_EQ(*s, 'I')) {
62bdc035
JH
616 /* INF or IND (1.#IND is "indeterminate", a certain type of NAN) */
617
305b8651 618 s++; if (s == send || isALPHA_FOLD_NE(*s, 'N')) return 0;
ff4eb398 619 s++; if (s == send) return 0;
305b8651 620 if (isALPHA_FOLD_EQ(*s, 'F')) {
ff4eb398 621 s++;
b8974fcb
JH
622 if (s < send && (isALPHA_FOLD_EQ(*s, 'I'))) {
623 int fail =
624 flags | IS_NUMBER_INFINITY | IS_NUMBER_NOT_INT | IS_NUMBER_TRAILING;
625 s++; if (s == send || isALPHA_FOLD_NE(*s, 'N')) return fail;
626 s++; if (s == send || isALPHA_FOLD_NE(*s, 'I')) return fail;
627 s++; if (s == send || isALPHA_FOLD_NE(*s, 'T')) return fail;
628 s++; if (s == send || isALPHA_FOLD_NE(*s, 'Y')) return fail;
3396ed30 629 s++;
b8974fcb
JH
630 } else if (odh) {
631 while (*s == '0') { /* 1.#INF00 */
632 s++;
633 }
3396ed30 634 }
b489e20f
JH
635 while (s < send && isSPACE(*s))
636 s++;
637 if (s < send && *s) {
3396ed30 638 flags |= IS_NUMBER_TRAILING;
fae4db12 639 }
ff4eb398
JH
640 flags |= IS_NUMBER_INFINITY | IS_NUMBER_NOT_INT;
641 }
e855f543 642 else if (isALPHA_FOLD_EQ(*s, 'D') && odh) { /* 1.#IND */
ff4eb398
JH
643 s++;
644 flags |= IS_NUMBER_NAN | IS_NUMBER_NOT_INT;
fae4db12
JH
645 while (*s == '0') { /* 1.#IND00 */
646 s++;
647 }
1e9aa12f
JH
648 if (*s) {
649 flags |= IS_NUMBER_TRAILING;
650 }
ff4eb398
JH
651 } else
652 return 0;
ff4eb398
JH
653 }
654 else {
62bdc035 655 /* Maybe NAN of some sort */
3823048b
JH
656
657 if (isALPHA_FOLD_EQ(*s, 'S') || isALPHA_FOLD_EQ(*s, 'Q')) {
658 /* snan, qNaN */
659 /* XXX do something with the snan/qnan difference */
660 s++; if (s == send) return 0;
661 }
662
663 if (isALPHA_FOLD_EQ(*s, 'N')) {
664 s++; if (s == send || isALPHA_FOLD_NE(*s, 'A')) return 0;
665 s++; if (s == send || isALPHA_FOLD_NE(*s, 'N')) return 0;
666 s++;
667
668 flags |= IS_NUMBER_NAN | IS_NUMBER_NOT_INT;
669
670 /* NaN can be followed by various stuff (NaNQ, NaNS), but
671 * there are also multiple different NaN values, and some
672 * implementations output the "payload" values,
673 * e.g. NaN123, NAN(abc), while some legacy implementations
674 * have weird stuff like NaN%. */
675 if (isALPHA_FOLD_EQ(*s, 'q') ||
676 isALPHA_FOLD_EQ(*s, 's')) {
677 /* "nanq" or "nans" are ok, though generating
678 * these portably is tricky. */
679 s++;
680 }
681 if (*s == '(') {
682 /* C99 style "nan(123)" or Perlish equivalent "nan($uv)". */
683 const char *t;
684 s++;
685 if (s == send) {
686 return flags | IS_NUMBER_TRAILING;
687 }
688 t = s + 1;
689 while (t < send && *t && *t != ')') {
690 t++;
691 }
692 if (t == send) {
693 return flags | IS_NUMBER_TRAILING;
694 }
695 if (*t == ')') {
696 int nantype;
697 UV nanval;
698 if (s[0] == '0' && s + 2 < t &&
699 isALPHA_FOLD_EQ(s[1], 'x') &&
700 isXDIGIT(s[2])) {
701 STRLEN len = t - s;
702 I32 flags = PERL_SCAN_ALLOW_UNDERSCORES;
703 nanval = grok_hex(s, &len, &flags, NULL);
704 if ((flags & PERL_SCAN_GREATER_THAN_UV_MAX)) {
705 nantype = 0;
706 } else {
707 nantype = IS_NUMBER_IN_UV;
708 }
709 s += len;
710 } else if (s[0] == '0' && s + 2 < t &&
711 isALPHA_FOLD_EQ(s[1], 'b') &&
712 (s[2] == '0' || s[2] == '1')) {
713 STRLEN len = t - s;
714 I32 flags = PERL_SCAN_ALLOW_UNDERSCORES;
715 nanval = grok_bin(s, &len, &flags, NULL);
716 if ((flags & PERL_SCAN_GREATER_THAN_UV_MAX)) {
717 nantype = 0;
718 } else {
719 nantype = IS_NUMBER_IN_UV;
720 }
721 s += len;
722 } else {
723 const char *u;
724 nantype =
725 grok_number_flags(s, t - s, &nanval,
726 PERL_SCAN_TRAILING |
727 PERL_SCAN_ALLOW_UNDERSCORES);
728 /* Unfortunately grok_number_flags() doesn't
729 * tell how far we got and the ')' will always
730 * be "trailing", so we need to double-check
731 * whether we had something dubious. */
732 for (u = s; u < t; u++) {
733 if (!isDIGIT(*u)) {
734 flags |= IS_NUMBER_TRAILING;
735 break;
736 }
737 }
738 s = u;
739 }
740
741 /* XXX Doesn't do octal: nan("0123").
742 * Probably not a big loss. */
743
744 if ((nantype & IS_NUMBER_NOT_INT) ||
745 !(nantype && IS_NUMBER_IN_UV)) {
746 /* XXX the nanval is currently unused, that is,
747 * not inserted as the NaN payload of the NV.
748 * But the above code already parses the C99
749 * nan(...) format. See below, and see also
750 * the nan() in POSIX.xs.
751 *
752 * Certain configuration combinations where
753 * NVSIZE is greater than UVSIZE mean that
754 * a single UV cannot contain all the possible
755 * NaN payload bits. There would need to be
756 * some more generic syntax than "nan($uv)".
757 *
758 * Issues to keep in mind:
759 *
760 * (1) In most common cases there would
761 * not be an integral number of bytes that
762 * could be set, only a certain number of bits.
763 * For example for the common case of
764 * NVSIZE == UVSIZE == 8 there is room for 52
765 * bits in the payload, but the most significant
766 * bit is commonly reserved for the
767 * signaling/quiet bit, leaving 51 bits.
768 * Furthermore, the C99 nan() is supposed
769 * to generate quiet NaNs, so it is doubtful
770 * whether it should be able to generate
771 * signaling NaNs. For the x86 80-bit doubles
772 * (if building a long double Perl) there would
773 * be 62 bits (s/q bit being the 63rd).
774 *
775 * (2) Endianness of the payload bits. If the
776 * payload is specified as an UV, the low-order
777 * bits of the UV are naturally little-endianed
778 * (rightmost) bits of the payload. The endianness
779 * of UVs and NVs can be different. */
780 return 0;
781 }
782 if (s < t) {
783 flags |= IS_NUMBER_TRAILING;
784 }
785 } else {
786 /* Looked like nan(...), but no close paren. */
787 flags |= IS_NUMBER_TRAILING;
788 }
789 } else {
790 while (s < send && isSPACE(*s))
791 s++;
792 if (s < send && *s) {
793 /* Note that we here implicitly accept (parse as
794 * "nan", but with warnings) also any other weird
795 * trailing stuff for "nan". In the above we just
796 * check that if we got the C99-style "nan(...)",
797 * the "..." looks sane.
798 * If in future we accept more ways of specifying
799 * the nan payload, the accepting would happen around
800 * here. */
801 flags |= IS_NUMBER_TRAILING;
802 }
803 }
804 s = send;
805 }
806 else
807 return 0;
ff4eb398
JH
808 }
809
b489e20f
JH
810 while (s < send && isSPACE(*s))
811 s++;
812
a5dc2484
JH
813#else
814 PERL_UNUSED_ARG(send);
815#endif /* #if defined(NV_INF) || defined(NV_NAN) */
a1fe7cea
JH
816 *sp = s;
817 return flags;
ff4eb398
JH
818}
819
13393a5e 820/*
3823048b 821=for apidoc grok_number_flags
13393a5e
JH
822
823Recognise (or not) a number. The type of the number is returned
824(0 if unrecognised), otherwise it is a bit-ORed combination of
796b6530
KW
825C<IS_NUMBER_IN_UV>, C<IS_NUMBER_GREATER_THAN_UV_MAX>, C<IS_NUMBER_NOT_INT>,
826C<IS_NUMBER_NEG>, C<IS_NUMBER_INFINITY>, C<IS_NUMBER_NAN> (defined in perl.h).
827
828If the value of the number can fit in a UV, it is returned in C<*valuep>.
829C<IS_NUMBER_IN_UV> will be set to indicate that C<*valuep> is valid, C<IS_NUMBER_IN_UV>
830will never be set unless C<*valuep> is valid, but C<*valuep> may have been assigned
831to during processing even though C<IS_NUMBER_IN_UV> is not set on return.
832If C<valuep> is C<NULL>, C<IS_NUMBER_IN_UV> will be set for the same cases as when
833C<valuep> is non-C<NULL>, but no actual assignment (or SEGV) will occur.
834
835C<IS_NUMBER_NOT_INT> will be set with C<IS_NUMBER_IN_UV> if trailing decimals were
836seen (in which case C<*valuep> gives the true value truncated to an integer), and
837C<IS_NUMBER_NEG> if the number is negative (in which case C<*valuep> holds the
838absolute value). C<IS_NUMBER_IN_UV> is not set if e notation was used or the
13393a5e
JH
839number is larger than a UV.
840
841C<flags> allows only C<PERL_SCAN_TRAILING>, which allows for trailing
842non-numeric text on an otherwise successful I<grok>, setting
843C<IS_NUMBER_TRAILING> on the result.
844
845=for apidoc grok_number
846
796b6530 847Identical to C<grok_number_flags()> with C<flags> set to zero.
13393a5e
JH
848
849=cut
850 */
851int
852Perl_grok_number(pTHX_ const char *pv, STRLEN len, UV *valuep)
853{
854 PERL_ARGS_ASSERT_GROK_NUMBER;
855
856 return grok_number_flags(pv, len, valuep, 0);
857}
858
945b524a
JH
859static const UV uv_max_div_10 = UV_MAX / 10;
860static const U8 uv_max_mod_10 = UV_MAX % 10;
861
3f7602fa 862int
3823048b 863Perl_grok_number_flags(pTHX_ const char *pv, STRLEN len, UV *valuep, U32 flags)
3f7602fa 864{
60939fb8 865 const char *s = pv;
c4420975 866 const char * const send = pv + len;
ae776a2c 867 const char *d;
60939fb8 868 int numtype = 0;
60939fb8 869
3823048b 870 PERL_ARGS_ASSERT_GROK_NUMBER_FLAGS;
7918f24d 871
60939fb8
NC
872 while (s < send && isSPACE(*s))
873 s++;
874 if (s == send) {
875 return 0;
876 } else if (*s == '-') {
877 s++;
878 numtype = IS_NUMBER_NEG;
879 }
880 else if (*s == '+')
aa42a541 881 s++;
60939fb8
NC
882
883 if (s == send)
884 return 0;
885
ae776a2c 886 /* The first digit (after optional sign): note that might
8c12dc63 887 * also point to "infinity" or "nan", or "1.#INF". */
ae776a2c
JH
888 d = s;
889
8c12dc63 890 /* next must be digit or the radix separator or beginning of infinity/nan */
60939fb8
NC
891 if (isDIGIT(*s)) {
892 /* UVs are at least 32 bits, so the first 9 decimal digits cannot
893 overflow. */
894 UV value = *s - '0';
895 /* This construction seems to be more optimiser friendly.
896 (without it gcc does the isDIGIT test and the *s - '0' separately)
897 With it gcc on arm is managing 6 instructions (6 cycles) per digit.
898 In theory the optimiser could deduce how far to unroll the loop
899 before checking for overflow. */
58bb9ec3
NC
900 if (++s < send) {
901 int digit = *s - '0';
f85b645f 902 if (inRANGE(digit, 0, 9)) {
60939fb8 903 value = value * 10 + digit;
58bb9ec3
NC
904 if (++s < send) {
905 digit = *s - '0';
f85b645f 906 if (inRANGE(digit, 0, 9)) {
60939fb8 907 value = value * 10 + digit;
58bb9ec3
NC
908 if (++s < send) {
909 digit = *s - '0';
f85b645f 910 if (inRANGE(digit, 0, 9)) {
60939fb8 911 value = value * 10 + digit;
58bb9ec3
NC
912 if (++s < send) {
913 digit = *s - '0';
f85b645f 914 if (inRANGE(digit, 0, 9)) {
60939fb8 915 value = value * 10 + digit;
58bb9ec3
NC
916 if (++s < send) {
917 digit = *s - '0';
f85b645f 918 if (inRANGE(digit, 0, 9)) {
60939fb8 919 value = value * 10 + digit;
58bb9ec3
NC
920 if (++s < send) {
921 digit = *s - '0';
f85b645f 922 if (inRANGE(digit, 0, 9)) {
60939fb8 923 value = value * 10 + digit;
58bb9ec3
NC
924 if (++s < send) {
925 digit = *s - '0';
f85b645f 926 if (inRANGE(digit, 0, 9)) {
60939fb8 927 value = value * 10 + digit;
58bb9ec3
NC
928 if (++s < send) {
929 digit = *s - '0';
f85b645f 930 if (inRANGE(digit, 0, 9)) {
60939fb8 931 value = value * 10 + digit;
58bb9ec3 932 if (++s < send) {
60939fb8
NC
933 /* Now got 9 digits, so need to check
934 each time for overflow. */
58bb9ec3 935 digit = *s - '0';
f85b645f 936 while ( inRANGE(digit, 0, 9)
945b524a
JH
937 && (value < uv_max_div_10
938 || (value == uv_max_div_10
939 && digit <= uv_max_mod_10))) {
60939fb8 940 value = value * 10 + digit;
58bb9ec3
NC
941 if (++s < send)
942 digit = *s - '0';
60939fb8
NC
943 else
944 break;
945 }
f85b645f 946 if (inRANGE(digit, 0, 9)
51bd16da 947 && (s < send)) {
60939fb8
NC
948 /* value overflowed.
949 skip the remaining digits, don't
950 worry about setting *valuep. */
951 do {
952 s++;
953 } while (s < send && isDIGIT(*s));
954 numtype |=
955 IS_NUMBER_GREATER_THAN_UV_MAX;
956 goto skip_value;
957 }
958 }
959 }
98994639 960 }
60939fb8
NC
961 }
962 }
963 }
964 }
965 }
966 }
967 }
968 }
969 }
970 }
971 }
98994639 972 }
60939fb8 973 }
98994639 974 }
60939fb8
NC
975 numtype |= IS_NUMBER_IN_UV;
976 if (valuep)
977 *valuep = value;
978
979 skip_value:
980 if (GROK_NUMERIC_RADIX(&s, send)) {
981 numtype |= IS_NUMBER_NOT_INT;
982 while (s < send && isDIGIT(*s)) /* optional digits after the radix */
983 s++;
98994639 984 }
60939fb8
NC
985 }
986 else if (GROK_NUMERIC_RADIX(&s, send)) {
987 numtype |= IS_NUMBER_NOT_INT | IS_NUMBER_IN_UV; /* valuep assigned below */
988 /* no digits before the radix means we need digits after it */
989 if (s < send && isDIGIT(*s)) {
990 do {
991 s++;
992 } while (s < send && isDIGIT(*s));
993 if (valuep) {
994 /* integer approximation is valid - it's 0. */
995 *valuep = 0;
996 }
98994639 997 }
60939fb8 998 else
ae776a2c 999 return 0;
ff4eb398 1000 }
60939fb8 1001
926f5fc6 1002 if (s > d && s < send) {
60939fb8 1003 /* we can have an optional exponent part */
305b8651 1004 if (isALPHA_FOLD_EQ(*s, 'e')) {
60939fb8
NC
1005 s++;
1006 if (s < send && (*s == '-' || *s == '+'))
1007 s++;
1008 if (s < send && isDIGIT(*s)) {
1009 do {
1010 s++;
1011 } while (s < send && isDIGIT(*s));
1012 }
3f7602fa
TC
1013 else if (flags & PERL_SCAN_TRAILING)
1014 return numtype | IS_NUMBER_TRAILING;
60939fb8 1015 else
3f7602fa
TC
1016 return 0;
1017
1018 /* The only flag we keep is sign. Blow away any "it's UV" */
1019 numtype &= IS_NUMBER_NEG;
1020 numtype |= IS_NUMBER_NOT_INT;
60939fb8
NC
1021 }
1022 }
1023 while (s < send && isSPACE(*s))
1024 s++;
1025 if (s >= send)
aa8b85de 1026 return numtype;
b59bf0b2 1027 if (memEQs(pv, len, "0 but true")) {
60939fb8
NC
1028 if (valuep)
1029 *valuep = 0;
1030 return IS_NUMBER_IN_UV;
1031 }
8c12dc63
JH
1032 /* We could be e.g. at "Inf" or "NaN", or at the "#" of "1.#INF". */
1033 if ((s + 2 < send) && strchr("inqs#", toFOLD(*s))) {
1034 /* Really detect inf/nan. Start at d, not s, since the above
1035 * code might have already consumed the "1." or "1". */
7eff3d39 1036 const int infnan = Perl_grok_infnan(aTHX_ &d, send);
8c12dc63
JH
1037 if ((infnan & IS_NUMBER_INFINITY)) {
1038 return (numtype | infnan); /* Keep sign for infinity. */
1039 }
1040 else if ((infnan & IS_NUMBER_NAN)) {
1041 return (numtype | infnan) & ~IS_NUMBER_NEG; /* Clear sign for nan. */
1042 }
1043 }
3f7602fa
TC
1044 else if (flags & PERL_SCAN_TRAILING) {
1045 return numtype | IS_NUMBER_TRAILING;
1046 }
1047
60939fb8 1048 return 0;
98994639
HS
1049}
1050
6313e544 1051/*
5d4a52b5 1052=for apidoc grok_atoUV
6313e544 1053
5d4a52b5 1054parse a string, looking for a decimal unsigned integer.
338aa8b0 1055
5d4a52b5
KW
1056On entry, C<pv> points to the beginning of the string;
1057C<valptr> points to a UV that will receive the converted value, if found;
1058C<endptr> is either NULL or points to a variable that points to one byte
1059beyond the point in C<pv> that this routine should examine.
1060If C<endptr> is NULL, C<pv> is assumed to be NUL-terminated.
f4379102 1061
5d4a52b5
KW
1062Returns FALSE if C<pv> doesn't represent a valid unsigned integer value (with
1063no leading zeros). Otherwise it returns TRUE, and sets C<*valptr> to that
1064value.
6313e544 1065
5d4a52b5
KW
1066If you constrain the portion of C<pv> that is looked at by this function (by
1067passing a non-NULL C<endptr>), and if the intial bytes of that portion form a
1068valid value, it will return TRUE, setting C<*endptr> to the byte following the
1069final digit of the value. But if there is no constraint at what's looked at,
1070all of C<pv> must be valid in order for TRUE to be returned.
6313e544 1071
5d4a52b5 1072The only characters this accepts are the decimal digits '0'..'9'.
338aa8b0 1073
5d4a52b5
KW
1074As opposed to L<atoi(3)> or L<strtol(3)>, C<grok_atoUV> does NOT allow optional
1075leading whitespace, nor negative inputs. If such features are required, the
1076calling code needs to explicitly implement those.
6313e544 1077
5d4a52b5
KW
1078Note that this function returns FALSE for inputs that would overflow a UV,
1079or have leading zeros. Thus a single C<0> is accepted, but not C<00> nor
1080C<01>, C<002>, I<etc>.
1081
1082Background: C<atoi> has severe problems with illegal inputs, it cannot be
d62b8c6a 1083used for incremental parsing, and therefore should be avoided
5d4a52b5 1084C<atoi> and C<strtol> are also affected by locale settings, which can also be
d62b8c6a
JH
1085seen as a bug (global state controlled by user environment).
1086
238217e5
JK
1087=cut
1088
6313e544
JH
1089*/
1090
22ff3130
HS
1091bool
1092Perl_grok_atoUV(const char *pv, UV *valptr, const char** endptr)
6313e544
JH
1093{
1094 const char* s = pv;
1095 const char** eptr;
1096 const char* end2; /* Used in case endptr is NULL. */
22ff3130 1097 UV val = 0; /* The parsed value. */
6313e544 1098
22ff3130 1099 PERL_ARGS_ASSERT_GROK_ATOUV;
6313e544 1100
5d4a52b5
KW
1101 if (endptr) {
1102 eptr = endptr;
1103 }
1104 else {
1105 end2 = s + strlen(s);
1106 eptr = &end2;
1107 }
1108
1109 if ( *eptr <= s
1110 || ! isDIGIT(*s))
1111 {
1112 return FALSE;
1113 }
1114
97d95d46
KW
1115 /* Single-digit inputs are quite common. */
1116 val = *s++ - '0';
1117 if (s < *eptr && isDIGIT(*s)) {
1118 /* Fail on extra leading zeros. */
1119 if (val == 0)
1120 return FALSE;
1121 while (s < *eptr && isDIGIT(*s)) {
1122 /* This could be unrolled like in grok_number(), but
1123 * the expected uses of this are not speed-needy, and
1124 * unlikely to need full 64-bitness. */
1125 const U8 digit = *s++ - '0';
1126 if (val < uv_max_div_10 ||
1127 (val == uv_max_div_10 && digit <= uv_max_mod_10)) {
1128 val = val * 10 + digit;
1129 } else {
22ff3130 1130 return FALSE;
6313e544
JH
1131 }
1132 }
97d95d46
KW
1133 }
1134
5d4a52b5
KW
1135 if (endptr == NULL) {
1136 if (*s) {
1137 return FALSE; /* If endptr is NULL, no trailing non-digits allowed. */
1138 }
1139 }
1140 else {
1141 *endptr = s;
75feedba 1142 }
97d95d46 1143
22ff3130
HS
1144 *valptr = val;
1145 return TRUE;
6313e544
JH
1146}
1147
ce6f496d 1148#ifndef Perl_strtod
4801ca72 1149STATIC NV
98994639
HS
1150S_mulexp10(NV value, I32 exponent)
1151{
1152 NV result = 1.0;
1153 NV power = 10.0;
1154 bool negative = 0;
1155 I32 bit;
1156
1157 if (exponent == 0)
1158 return value;
659c4b96
DM
1159 if (value == 0)
1160 return (NV)0;
87032ba1 1161
24866caa 1162 /* On OpenVMS VAX we by default use the D_FLOAT double format,
67597c89 1163 * and that format does not have *easy* capabilities [1] for
19c1206d
KW
1164 * overflowing doubles 'silently' as IEEE fp does. We also need
1165 * to support G_FLOAT on both VAX and Alpha, and though the exponent
1166 * range is much larger than D_FLOAT it still doesn't do silent
1167 * overflow. Therefore we need to detect early whether we would
1168 * overflow (this is the behaviour of the native string-to-float
24866caa 1169 * conversion routines, and therefore of native applications, too).
67597c89 1170 *
24866caa
CB
1171 * [1] Trying to establish a condition handler to trap floating point
1172 * exceptions is not a good idea. */
87032ba1
JH
1173
1174 /* In UNICOS and in certain Cray models (such as T90) there is no
1175 * IEEE fp, and no way at all from C to catch fp overflows gracefully.
1176 * There is something you can do if you are willing to use some
1177 * inline assembler: the instruction is called DFI-- but that will
1178 * disable *all* floating point interrupts, a little bit too large
1179 * a hammer. Therefore we need to catch potential overflows before
1180 * it's too late. */
353813d9 1181
a7157111 1182#if ((defined(VMS) && !defined(_IEEE_FP)) || defined(_UNICOS) || defined(DOUBLE_IS_VAX_FLOAT)) && defined(NV_MAX_10_EXP)
353813d9 1183 STMT_START {
c4420975 1184 const NV exp_v = log10(value);
353813d9
HS
1185 if (exponent >= NV_MAX_10_EXP || exponent + exp_v >= NV_MAX_10_EXP)
1186 return NV_MAX;
1187 if (exponent < 0) {
1188 if (-(exponent + exp_v) >= NV_MAX_10_EXP)
1189 return 0.0;
1190 while (-exponent >= NV_MAX_10_EXP) {
1191 /* combination does not overflow, but 10^(-exponent) does */
1192 value /= 10;
1193 ++exponent;
1194 }
1195 }
1196 } STMT_END;
87032ba1
JH
1197#endif
1198
353813d9
HS
1199 if (exponent < 0) {
1200 negative = 1;
1201 exponent = -exponent;
b27804d8
DM
1202#ifdef NV_MAX_10_EXP
1203 /* for something like 1234 x 10^-309, the action of calculating
1204 * the intermediate value 10^309 then returning 1234 / (10^309)
1205 * will fail, since 10^309 becomes infinity. In this case try to
1206 * refactor it as 123 / (10^308) etc.
1207 */
1208 while (value && exponent > NV_MAX_10_EXP) {
1209 exponent--;
1210 value /= 10;
1211 }
48853916
JH
1212 if (value == 0.0)
1213 return value;
b27804d8 1214#endif
353813d9 1215 }
c62e754c
JH
1216#if defined(__osf__)
1217 /* Even with cc -ieee + ieee_set_fp_control(IEEE_TRAP_ENABLE_INV)
1218 * Tru64 fp behavior on inf/nan is somewhat broken. Another way
1219 * to do this would be ieee_set_fp_control(IEEE_TRAP_ENABLE_OVF)
1220 * but that breaks another set of infnan.t tests. */
1221# define FP_OVERFLOWS_TO_ZERO
1222#endif
98994639
HS
1223 for (bit = 1; exponent; bit <<= 1) {
1224 if (exponent & bit) {
1225 exponent ^= bit;
1226 result *= power;
c62e754c
JH
1227#ifdef FP_OVERFLOWS_TO_ZERO
1228 if (result == 0)
a7157111 1229# ifdef NV_INF
c62e754c 1230 return value < 0 ? -NV_INF : NV_INF;
a7157111
JH
1231# else
1232 return value < 0 ? -FLT_MAX : FLT_MAX;
1233# endif
c62e754c 1234#endif
236f0012 1235 /* Floating point exceptions are supposed to be turned off,
19c1206d 1236 * but if we're obviously done, don't risk another iteration.
236f0012
CB
1237 */
1238 if (exponent == 0) break;
98994639
HS
1239 }
1240 power *= power;
1241 }
1242 return negative ? value / result : value * result;
1243}
ce6f496d 1244#endif /* #ifndef Perl_strtod */
98994639 1245
ce6f496d 1246#ifdef Perl_strtod
b93d1309 1247# define ATOF(s, x) my_atof2(s, &x)
f7b64c80 1248#else
b93d1309 1249# define ATOF(s, x) Perl_atof2(s, x)
f7b64c80 1250#endif
b93d1309 1251
98994639
HS
1252NV
1253Perl_my_atof(pTHX_ const char* s)
1254{
f720c878
KW
1255 /* 's' must be NUL terminated */
1256
98994639 1257 NV x = 0.0;
9eda1ea6
KW
1258
1259 PERL_ARGS_ASSERT_MY_ATOF;
1260
b93d1309 1261#if ! defined(USE_LOCALE_NUMERIC)
9eda1ea6 1262
b93d1309 1263 ATOF(s, x);
9eda1ea6
KW
1264
1265#else
7918f24d 1266
a2287a13 1267 {
67d796ae
KW
1268 DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
1269 STORE_LC_NUMERIC_SET_TO_NEEDED();
fdf55d20
KW
1270 if (! (PL_numeric_radix_sv && IN_LC(LC_NUMERIC))) {
1271 ATOF(s,x);
1272 }
1273 else {
19c1206d 1274
e4850248
KW
1275 /* Look through the string for the first thing that looks like a
1276 * decimal point: either the value in the current locale or the
1277 * standard fallback of '.'. The one which appears earliest in the
1278 * input string is the one that we should have atof look for. Note
1279 * that we have to determine this beforehand because on some
1280 * systems, Perl_atof2 is just a wrapper around the system's atof.
1281 * */
1ae85f6c
KW
1282 const char * const standard_pos = strchr(s, '.');
1283 const char * const local_pos
1284 = strstr(s, SvPV_nolen(PL_numeric_radix_sv));
1285 const bool use_standard_radix
1286 = standard_pos && (!local_pos || standard_pos < local_pos);
78787052 1287
665873e9 1288 if (use_standard_radix) {
e4850248 1289 SET_NUMERIC_STANDARD();
665873e9
KW
1290 LOCK_LC_NUMERIC_STANDARD();
1291 }
78787052 1292
b93d1309 1293 ATOF(s,x);
78787052 1294
665873e9
KW
1295 if (use_standard_radix) {
1296 UNLOCK_LC_NUMERIC_STANDARD();
67d796ae 1297 SET_NUMERIC_UNDERLYING();
665873e9 1298 }
e4850248 1299 }
a2287a13
KW
1300 RESTORE_LC_NUMERIC();
1301 }
9eda1ea6 1302
98994639 1303#endif
9eda1ea6 1304
98994639
HS
1305 return x;
1306}
1307
a7157111 1308#if defined(NV_INF) || defined(NV_NAN)
3c81f0b3
DD
1309
1310#ifdef USING_MSVC6
1311# pragma warning(push)
1312# pragma warning(disable:4756;disable:4056)
1313#endif
829757a4 1314static char*
5563f457 1315S_my_atof_infnan(pTHX_ const char* s, bool negative, const char* send, NV* value)
829757a4
JH
1316{
1317 const char *p0 = negative ? s - 1 : s;
1318 const char *p = p0;
7eff3d39 1319 const int infnan = grok_infnan(&p, send);
829757a4
JH
1320 if (infnan && p != p0) {
1321 /* If we can generate inf/nan directly, let's do so. */
1322#ifdef NV_INF
1323 if ((infnan & IS_NUMBER_INFINITY)) {
3823048b 1324 *value = (infnan & IS_NUMBER_NEG) ? -NV_INF: NV_INF;
829757a4
JH
1325 return (char*)p;
1326 }
1327#endif
1328#ifdef NV_NAN
1329 if ((infnan & IS_NUMBER_NAN)) {
3823048b 1330 *value = NV_NAN;
829757a4
JH
1331 return (char*)p;
1332 }
1333#endif
1334#ifdef Perl_strtod
68611e6f 1335 /* If still here, we didn't have either NV_INF or NV_NAN,
829757a4
JH
1336 * and can try falling back to native strtod/strtold.
1337 *
1338 * The native interface might not recognize all the possible
1339 * inf/nan strings Perl recognizes. What we can try
1340 * is to try faking the input. We will try inf/-inf/nan
1341 * as the most promising/portable input. */
1342 {
6d37e916 1343 const char* fake = "silence compiler warning";
829757a4
JH
1344 char* endp;
1345 NV nv;
a7157111 1346#ifdef NV_INF
829757a4
JH
1347 if ((infnan & IS_NUMBER_INFINITY)) {
1348 fake = ((infnan & IS_NUMBER_NEG)) ? "-inf" : "inf";
1349 }
a7157111
JH
1350#endif
1351#ifdef NV_NAN
1352 if ((infnan & IS_NUMBER_NAN)) {
829757a4
JH
1353 fake = "nan";
1354 }
a7157111 1355#endif
6d37e916 1356 assert(strNE(fake, "silence compiler warning"));
829757a4
JH
1357 nv = Perl_strtod(fake, &endp);
1358 if (fake != endp) {
a7157111 1359#ifdef NV_INF
829757a4 1360 if ((infnan & IS_NUMBER_INFINITY)) {
a7157111 1361# ifdef Perl_isinf
829757a4
JH
1362 if (Perl_isinf(nv))
1363 *value = nv;
a7157111 1364# else
829757a4
JH
1365 /* last resort, may generate SIGFPE */
1366 *value = Perl_exp((NV)1e9);
1367 if ((infnan & IS_NUMBER_NEG))
1368 *value = -*value;
a7157111 1369# endif
829757a4
JH
1370 return (char*)p; /* p, not endp */
1371 }
a7157111
JH
1372#endif
1373#ifdef NV_NAN
1374 if ((infnan & IS_NUMBER_NAN)) {
1375# ifdef Perl_isnan
829757a4
JH
1376 if (Perl_isnan(nv))
1377 *value = nv;
a7157111 1378# else
829757a4
JH
1379 /* last resort, may generate SIGFPE */
1380 *value = Perl_log((NV)-1.0);
a7157111 1381# endif
829757a4 1382 return (char*)p; /* p, not endp */
a7157111 1383#endif
829757a4
JH
1384 }
1385 }
1386 }
1387#endif /* #ifdef Perl_strtod */
1388 }
1389 return NULL;
1390}
3c81f0b3
DD
1391#ifdef USING_MSVC6
1392# pragma warning(pop)
1393#endif
829757a4 1394
a7157111
JH
1395#endif /* if defined(NV_INF) || defined(NV_NAN) */
1396
98994639
HS
1397char*
1398Perl_my_atof2(pTHX_ const char* orig, NV* value)
1399{
6928bedc
KW
1400 PERL_ARGS_ASSERT_MY_ATOF2;
1401 return my_atof3(orig, value, 0);
1402}
1403
1404char*
16411967 1405Perl_my_atof3(pTHX_ const char* orig, NV* value, const STRLEN len)
6928bedc 1406{
e1ec3a88 1407 const char* s = orig;
a4eca1d4 1408 NV result[3] = {0.0, 0.0, 0.0};
ce6f496d 1409#if defined(USE_PERL_ATOF) || defined(Perl_strtod)
6928bedc
KW
1410 const char* send = s + ((len != 0)
1411 ? len
1412 : strlen(orig)); /* one past the last */
a4eca1d4
JH
1413 bool negative = 0;
1414#endif
ce6f496d 1415#if defined(USE_PERL_ATOF) && !defined(Perl_strtod)
a4eca1d4 1416 UV accumulator[2] = {0,0}; /* before/after dp */
8194bf88 1417 bool seen_digit = 0;
20f6aaab
AS
1418 I32 exp_adjust[2] = {0,0};
1419 I32 exp_acc[2] = {-1, -1};
1420 /* the current exponent adjust for the accumulators */
98994639 1421 I32 exponent = 0;
8194bf88 1422 I32 seen_dp = 0;
20f6aaab
AS
1423 I32 digit = 0;
1424 I32 old_digit = 0;
8194bf88 1425 I32 sig_digits = 0; /* noof significant digits seen so far */
a4eca1d4 1426#endif
8194bf88 1427
ce6f496d 1428#if defined(USE_PERL_ATOF) || defined(Perl_strtod)
6928bedc 1429 PERL_ARGS_ASSERT_MY_ATOF3;
7918f24d 1430
a4eca1d4 1431 /* leading whitespace */
6928bedc 1432 while (s < send && isSPACE(*s))
a4eca1d4
JH
1433 ++s;
1434
1435 /* sign */
1436 switch (*s) {
1437 case '-':
1438 negative = 1;
1439 /* FALLTHROUGH */
1440 case '+':
1441 ++s;
1442 }
1443#endif
1444
ce6f496d 1445#ifdef Perl_strtod
a4eca1d4
JH
1446 {
1447 char* endp;
d94e901a
KW
1448 char* copy = NULL;
1449
adc55e02 1450 if ((endp = S_my_atof_infnan(aTHX_ s, negative, send, value)))
a4eca1d4 1451 return endp;
d94e901a
KW
1452
1453 /* If the length is passed in, the input string isn't NUL-terminated,
1454 * and in it turns out the function below assumes it is; therefore we
1455 * create a copy and NUL-terminate that */
1456 if (len) {
1457 Newx(copy, len + 1, char);
1458 Copy(orig, copy, len, char);
1459 copy[len] = '\0';
1460 s = copy + (s - orig);
1461 }
1462
ce6f496d 1463 result[2] = Perl_strtod(s, &endp);
d94e901a
KW
1464
1465 /* If we created a copy, 'endp' is in terms of that. Convert back to
1466 * the original */
1467 if (copy) {
aac39b03 1468 s = (s - copy) + (char *) orig;
d94e901a
KW
1469 endp = (endp - copy) + (char *) orig;
1470 Safefree(copy);
1471 }
1472
a4eca1d4
JH
1473 if (s != endp) {
1474 *value = negative ? -result[2] : result[2];
1475 return endp;
1476 }
1477 return NULL;
1478 }
1479#elif defined(USE_PERL_ATOF)
1480
8194bf88
DM
1481/* There is no point in processing more significant digits
1482 * than the NV can hold. Note that NV_DIG is a lower-bound value,
1483 * while we need an upper-bound value. We add 2 to account for this;
1484 * since it will have been conservative on both the first and last digit.
1485 * For example a 32-bit mantissa with an exponent of 4 would have
1486 * exact values in the set
1487 * 4
1488 * 8
1489 * ..
1490 * 17179869172
1491 * 17179869176
1492 * 17179869180
1493 *
1494 * where for the purposes of calculating NV_DIG we would have to discount
1495 * both the first and last digit, since neither can hold all values from
1496 * 0..9; but for calculating the value we must examine those two digits.
1497 */
ffa277e5
EAS
1498#ifdef MAX_SIG_DIG_PLUS
1499 /* It is not necessarily the case that adding 2 to NV_DIG gets all the
1500 possible digits in a NV, especially if NVs are not IEEE compliant
1501 (e.g., long doubles on IRIX) - Allen <allens@cpan.org> */
1502# define MAX_SIG_DIGITS (NV_DIG+MAX_SIG_DIG_PLUS)
1503#else
1504# define MAX_SIG_DIGITS (NV_DIG+2)
1505#endif
8194bf88
DM
1506
1507/* the max number we can accumulate in a UV, and still safely do 10*N+9 */
1508#define MAX_ACCUMULATE ( (UV) ((UV_MAX - 9)/10))
98994639 1509
a5dc2484 1510#if defined(NV_INF) || defined(NV_NAN)
ae776a2c 1511 {
7eff3d39 1512 char* endp;
5563f457 1513 if ((endp = S_my_atof_infnan(aTHX_ s, negative, send, value)))
7eff3d39 1514 return endp;
ae776a2c 1515 }
a5dc2484 1516#endif
2b54f59f 1517
8194bf88
DM
1518 /* we accumulate digits into an integer; when this becomes too
1519 * large, we add the total to NV and start again */
98994639 1520
6928bedc 1521 while (s < send) {
8194bf88
DM
1522 if (isDIGIT(*s)) {
1523 seen_digit = 1;
20f6aaab 1524 old_digit = digit;
8194bf88 1525 digit = *s++ - '0';
20f6aaab
AS
1526 if (seen_dp)
1527 exp_adjust[1]++;
98994639 1528
8194bf88
DM
1529 /* don't start counting until we see the first significant
1530 * digit, eg the 5 in 0.00005... */
1531 if (!sig_digits && digit == 0)
1532 continue;
1533
1534 if (++sig_digits > MAX_SIG_DIGITS) {
98994639 1535 /* limits of precision reached */
20f6aaab
AS
1536 if (digit > 5) {
1537 ++accumulator[seen_dp];
1538 } else if (digit == 5) {
1539 if (old_digit % 2) { /* round to even - Allen */
1540 ++accumulator[seen_dp];
1541 }
1542 }
1543 if (seen_dp) {
1544 exp_adjust[1]--;
1545 } else {
1546 exp_adjust[0]++;
1547 }
8194bf88 1548 /* skip remaining digits */
6928bedc 1549 while (s < send && isDIGIT(*s)) {
98994639 1550 ++s;
20f6aaab
AS
1551 if (! seen_dp) {
1552 exp_adjust[0]++;
1553 }
98994639
HS
1554 }
1555 /* warn of loss of precision? */
98994639 1556 }
8194bf88 1557 else {
20f6aaab 1558 if (accumulator[seen_dp] > MAX_ACCUMULATE) {
8194bf88 1559 /* add accumulator to result and start again */
20f6aaab
AS
1560 result[seen_dp] = S_mulexp10(result[seen_dp],
1561 exp_acc[seen_dp])
1562 + (NV)accumulator[seen_dp];
1563 accumulator[seen_dp] = 0;
1564 exp_acc[seen_dp] = 0;
98994639 1565 }
20f6aaab
AS
1566 accumulator[seen_dp] = accumulator[seen_dp] * 10 + digit;
1567 ++exp_acc[seen_dp];
98994639 1568 }
8194bf88 1569 }
e1ec3a88 1570 else if (!seen_dp && GROK_NUMERIC_RADIX(&s, send)) {
8194bf88 1571 seen_dp = 1;
20f6aaab 1572 if (sig_digits > MAX_SIG_DIGITS) {
6928bedc 1573 while (s < send && isDIGIT(*s)) {
20f6aaab 1574 ++s;
9604fbf0 1575 }
20f6aaab
AS
1576 break;
1577 }
8194bf88
DM
1578 }
1579 else {
1580 break;
98994639
HS
1581 }
1582 }
1583
20f6aaab
AS
1584 result[0] = S_mulexp10(result[0], exp_acc[0]) + (NV)accumulator[0];
1585 if (seen_dp) {
1586 result[1] = S_mulexp10(result[1], exp_acc[1]) + (NV)accumulator[1];
1587 }
98994639 1588
6928bedc 1589 if (s < send && seen_digit && (isALPHA_FOLD_EQ(*s, 'e'))) {
98994639
HS
1590 bool expnegative = 0;
1591
1592 ++s;
1593 switch (*s) {
1594 case '-':
1595 expnegative = 1;
924ba076 1596 /* FALLTHROUGH */
98994639
HS
1597 case '+':
1598 ++s;
1599 }
6928bedc 1600 while (s < send && isDIGIT(*s))
98994639
HS
1601 exponent = exponent * 10 + (*s++ - '0');
1602 if (expnegative)
1603 exponent = -exponent;
1604 }
1605
1606 /* now apply the exponent */
20f6aaab
AS
1607
1608 if (seen_dp) {
1609 result[2] = S_mulexp10(result[0],exponent+exp_adjust[0])
1610 + S_mulexp10(result[1],exponent-exp_adjust[1]);
1611 } else {
1612 result[2] = S_mulexp10(result[0],exponent+exp_adjust[0]);
1613 }
98994639
HS
1614
1615 /* now apply the sign */
1616 if (negative)
20f6aaab 1617 result[2] = -result[2];
a36244b7 1618#endif /* USE_PERL_ATOF */
20f6aaab 1619 *value = result[2];
73d840c0 1620 return (char *)s;
98994639
HS
1621}
1622
5d34af89 1623/*
3d9d9213 1624=for apidoc isinfnan
5d34af89 1625
796b6530
KW
1626C<Perl_isinfnan()> is utility function that returns true if the NV
1627argument is either an infinity or a C<NaN>, false otherwise. To test
1628in more detail, use C<Perl_isinf()> and C<Perl_isnan()>.
5d34af89 1629
68611e6f
JH
1630This is also the logical inverse of Perl_isfinite().
1631
5d34af89
JH
1632=cut
1633*/
1cd88304
JH
1634bool
1635Perl_isinfnan(NV nv)
1636{
a5dc2484 1637 PERL_UNUSED_ARG(nv);
1cd88304
JH
1638#ifdef Perl_isinf
1639 if (Perl_isinf(nv))
1640 return TRUE;
1641#endif
1642#ifdef Perl_isnan
1643 if (Perl_isnan(nv))
1644 return TRUE;
1645#endif
1646 return FALSE;
1647}
1648
354b74ae
FC
1649/*
1650=for apidoc
1651
796b6530 1652Checks whether the argument would be either an infinity or C<NaN> when used
354b74ae 1653as a number, but is careful not to trigger non-numeric or uninitialized
796b6530 1654warnings. it assumes the caller has done C<SvGETMAGIC(sv)> already.
354b74ae
FC
1655
1656=cut
1657*/
1658
1659bool
1660Perl_isinfnansv(pTHX_ SV *sv)
1661{
1662 PERL_ARGS_ASSERT_ISINFNANSV;
1663 if (!SvOK(sv))
1664 return FALSE;
1665 if (SvNOKp(sv))
1666 return Perl_isinfnan(SvNVX(sv));
1667 if (SvIOKp(sv))
1668 return FALSE;
1669 {
1670 STRLEN len;
1671 const char *s = SvPV_nomg_const(sv, len);
3823048b 1672 return cBOOL(grok_infnan(&s, s+len));
354b74ae
FC
1673 }
1674}
1675
d67dac15 1676#ifndef HAS_MODFL
68611e6f
JH
1677/* C99 has truncl, pre-C99 Solaris had aintl. We can use either with
1678 * copysignl to emulate modfl, which is in some platforms missing or
1679 * broken. */
d67dac15
JH
1680# if defined(HAS_TRUNCL) && defined(HAS_COPYSIGNL)
1681long double
1682Perl_my_modfl(long double x, long double *ip)
1683{
68611e6f
JH
1684 *ip = truncl(x);
1685 return (x == *ip ? copysignl(0.0L, x) : x - *ip);
d67dac15
JH
1686}
1687# elif defined(HAS_AINTL) && defined(HAS_COPYSIGNL)
55954f19
JH
1688long double
1689Perl_my_modfl(long double x, long double *ip)
1690{
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JH
1691 *ip = aintl(x);
1692 return (x == *ip ? copysignl(0.0L, x) : x - *ip);
55954f19 1693}
d67dac15 1694# endif
55954f19
JH
1695#endif
1696
7b9b7dff 1697/* Similarly, with ilogbl and scalbnl we can emulate frexpl. */
55954f19
JH
1698#if ! defined(HAS_FREXPL) && defined(HAS_ILOGBL) && defined(HAS_SCALBNL)
1699long double
1700Perl_my_frexpl(long double x, int *e) {
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JH
1701 *e = x == 0.0L ? 0 : ilogbl(x) + 1;
1702 return (scalbnl(x, -*e));
55954f19
JH
1703}
1704#endif
66610fdd
RGS
1705
1706/*
ed140128
AD
1707=for apidoc Perl_signbit
1708
1709Return a non-zero integer if the sign bit on an NV is set, and 0 if
19c1206d 1710it is not.
ed140128 1711
796b6530
KW
1712If F<Configure> detects this system has a C<signbit()> that will work with
1713our NVs, then we just use it via the C<#define> in F<perl.h>. Otherwise,
8b7fad81 1714fall back on this implementation. The main use of this function
796b6530 1715is catching C<-0.0>.
ed140128 1716
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KW
1717C<Configure> notes: This function is called C<'Perl_signbit'> instead of a
1718plain C<'signbit'> because it is easy to imagine a system having a C<signbit()>
ed140128 1719function or macro that doesn't happen to work with our particular choice
796b6530 1720of NVs. We shouldn't just re-C<#define> C<signbit> as C<Perl_signbit> and expect
ed140128 1721the standard system headers to be happy. Also, this is a no-context
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KW
1722function (no C<pTHX_>) because C<Perl_signbit()> is usually re-C<#defined> in
1723F<perl.h> as a simple macro call to the system's C<signbit()>.
1724Users should just always call C<Perl_signbit()>.
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AD
1725
1726=cut
1727*/
1728#if !defined(HAS_SIGNBIT)
1729int
1730Perl_signbit(NV x) {
8b7fad81 1731# ifdef Perl_fp_class_nzero
406d5545
JH
1732 return Perl_fp_class_nzero(x);
1733 /* Try finding the high byte, and assume it's highest bit
1734 * is the sign. This assumption is probably wrong somewhere. */
572cd850
JH
1735# elif defined(USE_LONG_DOUBLE) && LONG_DOUBLEKIND == LONG_DOUBLE_IS_X86_80_BIT_LITTLE_ENDIAN
1736 return (((unsigned char *)&x)[9] & 0x80);
1737# elif defined(NV_LITTLE_ENDIAN)
1738 /* Note that NVSIZE is sizeof(NV), which would make the below be
1739 * wrong if the end bytes are unused, which happens with the x86
1740 * 80-bit long doubles, which is why take care of that above. */
1741 return (((unsigned char *)&x)[NVSIZE - 1] & 0x80);
1742# elif defined(NV_BIG_ENDIAN)
1743 return (((unsigned char *)&x)[0] & 0x80);
1744# else
406d5545 1745 /* This last resort fallback is wrong for the negative zero. */
3585840c 1746 return (x < 0.0) ? 1 : 0;
572cd850 1747# endif
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AD
1748}
1749#endif
1750
1751/*
14d04a33 1752 * ex: set ts=8 sts=4 sw=4 et:
37442d52 1753 */