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Implement grok_atou as safe/strict atoi replacement.
[perl5.git] / numeric.c
CommitLineData
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
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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
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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;
42 return ((U32) f) | (1 + U32_MAX >> 1);
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;
60 return (I32)(((U32) f) | (1 + U32_MAX >> 1));
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;
79 return (IV)(((UV) f) | (1 + UV_MAX >> 1));
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;
97 return ((UV) f) | (1 + UV_MAX >> 1);
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
110On entry I<start> and I<*len> give the string to scan, I<*flags> gives
111conversion flags, and I<result> should be NULL or a pointer to an NV.
112The scan stops at the end of the string, or the first invalid character.
7b667b5f
MHM
113Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in I<*flags>, encountering an
114invalid character will also trigger a warning.
115On return I<*len> is set to the length of the scanned string,
116and I<*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,
72d33970 119and nothing is written to I<*result>. If the value is > UV_MAX C<grok_bin>
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NC
120returns UV_MAX, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
121and writes the value to I<*result> (or the value is discarded if I<result>
122is NULL).
123
7b667b5f 124The binary number may optionally be prefixed with "0b" or "b" unless
72d33970 125C<PERL_SCAN_DISALLOW_PREFIX> is set in I<*flags> on entry. If
a4c04bdc 126C<PERL_SCAN_ALLOW_UNDERSCORES> is set in I<*flags> then the binary
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127number may use '_' characters to separate digits.
128
129=cut
02470786
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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
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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) {
a674e8db 156 if (s[0] == 'b' || s[0] == 'B') {
a4c04bdc
NC
157 s++;
158 len--;
159 }
a674e8db 160 else if (len >= 2 && s[0] == '0' && (s[1] == 'b' || 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 }
53305cf1
NC
207
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
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228/*
229=for apidoc grok_hex
230
231converts a string representing a hex number to numeric form.
232
c2da02fc 233On entry I<start> and I<*len_p> give the string to scan, I<*flags> gives
53305cf1 234conversion flags, and I<result> should be NULL or a pointer to an NV.
7b667b5f
MHM
235The scan stops at the end of the string, or the first invalid character.
236Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in I<*flags>, encountering an
237invalid character will also trigger a warning.
238On return I<*len> is set to the length of the scanned string,
239and I<*flags> gives output flags.
53305cf1
NC
240
241If the value is <= UV_MAX it is returned as a UV, the output flags are clear,
72d33970 242and nothing is written to I<*result>. If the value is > UV_MAX C<grok_hex>
53305cf1
NC
243returns UV_MAX, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
244and writes the value to I<*result> (or the value is discarded if I<result>
245is NULL).
246
d1be9408 247The hex number may optionally be prefixed with "0x" or "x" unless
72d33970 248C<PERL_SCAN_DISALLOW_PREFIX> is set in I<*flags> on entry. If
a4c04bdc 249C<PERL_SCAN_ALLOW_UNDERSCORES> is set in I<*flags> then the hex
53305cf1
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250number may use '_' characters to separate digits.
251
252=cut
02470786
KW
253
254Not documented yet because experimental is C<PERL_SCAN_SILENT_NON_PORTABLE
255which suppresses any message for non-portable numbers that are still valid
256on this platform.
53305cf1
NC
257 */
258
259UV
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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) {
a674e8db 277 if (s[0] == 'x' || s[0] == 'X') {
a4c04bdc
NC
278 s++;
279 len--;
280 }
a674e8db 281 else if (len >= 2 && s[0] == '0' && (s[1] == 'x' || 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 }
328
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
354On entry I<start> and I<*len> give the string to scan, I<*flags> gives
355conversion flags, and I<result> should be NULL or a pointer to an NV.
356The scan stops at the end of the string, or the first invalid character.
357Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in I<*flags>, encountering an
154bd527 3588 or 9 will also trigger a warning.
7b667b5f
MHM
359On return I<*len> is set to the length of the scanned string,
360and I<*flags> gives output flags.
361
362If the value is <= UV_MAX it is returned as a UV, the output flags are clear,
72d33970 363and nothing is written to I<*result>. If the value is > UV_MAX C<grok_oct>
7b667b5f
MHM
364returns UV_MAX, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
365and writes the value to I<*result> (or the value is discarded if I<result>
366is NULL).
367
368If C<PERL_SCAN_ALLOW_UNDERSCORES> is set in I<*flags> then the octal
369number may use '_' 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 }
53305cf1
NC
435
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{
521#ifdef USE_LOCALE_NUMERIC
7918f24d
NC
522 PERL_ARGS_ASSERT_GROK_NUMERIC_RADIX;
523
d6ded950 524 if (IN_LC(LC_NUMERIC)) {
21431899
KW
525 DECLARE_STORE_LC_NUMERIC_SET_TO_NEEDED();
526 if (PL_numeric_radix_sv) {
c5a7e38e
KW
527 STRLEN len;
528 const char * const radix = SvPV(PL_numeric_radix_sv, len);
529 if (*sp + len <= send && memEQ(*sp, radix, len)) {
530 *sp += len;
531 RESTORE_LC_NUMERIC();
532 return TRUE;
533 }
21431899
KW
534 }
535 RESTORE_LC_NUMERIC();
98994639
HS
536 }
537 /* always try "." if numeric radix didn't match because
538 * we may have data from different locales mixed */
539#endif
7918f24d
NC
540
541 PERL_ARGS_ASSERT_GROK_NUMERIC_RADIX;
542
98994639
HS
543 if (*sp < send && **sp == '.') {
544 ++*sp;
545 return TRUE;
546 }
547 return FALSE;
548}
549
550/*
3f7602fa 551=for apidoc grok_number_flags
98994639
HS
552
553Recognise (or not) a number. The type of the number is returned
554(0 if unrecognised), otherwise it is a bit-ORed combination of
555IS_NUMBER_IN_UV, IS_NUMBER_GREATER_THAN_UV_MAX, IS_NUMBER_NOT_INT,
aa8b85de 556IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUMBER_NAN (defined in perl.h).
60939fb8 557
cd164854 558If the value of the number can fit in a UV, it is returned in the *valuep
60939fb8
NC
559IS_NUMBER_IN_UV will be set to indicate that *valuep is valid, IS_NUMBER_IN_UV
560will never be set unless *valuep is valid, but *valuep may have been assigned
561to during processing even though IS_NUMBER_IN_UV is not set on return.
562If valuep is NULL, IS_NUMBER_IN_UV will be set for the same cases as when
563valuep is non-NULL, but no actual assignment (or SEGV) will occur.
564
565IS_NUMBER_NOT_INT will be set with IS_NUMBER_IN_UV if trailing decimals were
566seen (in which case *valuep gives the true value truncated to an integer), and
567IS_NUMBER_NEG if the number is negative (in which case *valuep holds the
568absolute value). IS_NUMBER_IN_UV is not set if e notation was used or the
569number is larger than a UV.
98994639 570
3f7602fa
TC
571C<flags> allows only C<PERL_SCAN_TRAILING>, which allows for trailing
572non-numeric text on an otherwise successful I<grok>, setting
573C<IS_NUMBER_TRAILING> on the result.
574
575=for apidoc grok_number
576
577Identical to grok_number_flags() with flags set to zero.
578
98994639
HS
579=cut
580 */
581int
582Perl_grok_number(pTHX_ const char *pv, STRLEN len, UV *valuep)
583{
3f7602fa
TC
584 PERL_ARGS_ASSERT_GROK_NUMBER;
585
586 return grok_number_flags(pv, len, valuep, 0);
587}
588
589int
590Perl_grok_number_flags(pTHX_ const char *pv, STRLEN len, UV *valuep, U32 flags)
591{
60939fb8 592 const char *s = pv;
c4420975 593 const char * const send = pv + len;
60939fb8
NC
594 const UV max_div_10 = UV_MAX / 10;
595 const char max_mod_10 = UV_MAX % 10;
596 int numtype = 0;
597 int sawinf = 0;
aa8b85de 598 int sawnan = 0;
60939fb8 599
3f7602fa 600 PERL_ARGS_ASSERT_GROK_NUMBER_FLAGS;
7918f24d 601
60939fb8
NC
602 while (s < send && isSPACE(*s))
603 s++;
604 if (s == send) {
605 return 0;
606 } else if (*s == '-') {
607 s++;
608 numtype = IS_NUMBER_NEG;
609 }
610 else if (*s == '+')
aa42a541 611 s++;
60939fb8
NC
612
613 if (s == send)
614 return 0;
615
616 /* next must be digit or the radix separator or beginning of infinity */
617 if (isDIGIT(*s)) {
618 /* UVs are at least 32 bits, so the first 9 decimal digits cannot
619 overflow. */
620 UV value = *s - '0';
621 /* This construction seems to be more optimiser friendly.
622 (without it gcc does the isDIGIT test and the *s - '0' separately)
623 With it gcc on arm is managing 6 instructions (6 cycles) per digit.
624 In theory the optimiser could deduce how far to unroll the loop
625 before checking for overflow. */
58bb9ec3
NC
626 if (++s < send) {
627 int digit = *s - '0';
60939fb8
NC
628 if (digit >= 0 && digit <= 9) {
629 value = value * 10 + digit;
58bb9ec3
NC
630 if (++s < send) {
631 digit = *s - '0';
60939fb8
NC
632 if (digit >= 0 && digit <= 9) {
633 value = value * 10 + digit;
58bb9ec3
NC
634 if (++s < send) {
635 digit = *s - '0';
60939fb8
NC
636 if (digit >= 0 && digit <= 9) {
637 value = value * 10 + digit;
58bb9ec3
NC
638 if (++s < send) {
639 digit = *s - '0';
60939fb8
NC
640 if (digit >= 0 && digit <= 9) {
641 value = value * 10 + digit;
58bb9ec3
NC
642 if (++s < send) {
643 digit = *s - '0';
60939fb8
NC
644 if (digit >= 0 && digit <= 9) {
645 value = value * 10 + digit;
58bb9ec3
NC
646 if (++s < send) {
647 digit = *s - '0';
60939fb8
NC
648 if (digit >= 0 && digit <= 9) {
649 value = value * 10 + digit;
58bb9ec3
NC
650 if (++s < send) {
651 digit = *s - '0';
60939fb8
NC
652 if (digit >= 0 && digit <= 9) {
653 value = value * 10 + digit;
58bb9ec3
NC
654 if (++s < send) {
655 digit = *s - '0';
60939fb8
NC
656 if (digit >= 0 && digit <= 9) {
657 value = value * 10 + digit;
58bb9ec3 658 if (++s < send) {
60939fb8
NC
659 /* Now got 9 digits, so need to check
660 each time for overflow. */
58bb9ec3 661 digit = *s - '0';
60939fb8
NC
662 while (digit >= 0 && digit <= 9
663 && (value < max_div_10
664 || (value == max_div_10
665 && digit <= max_mod_10))) {
666 value = value * 10 + digit;
58bb9ec3
NC
667 if (++s < send)
668 digit = *s - '0';
60939fb8
NC
669 else
670 break;
671 }
672 if (digit >= 0 && digit <= 9
51bd16da 673 && (s < send)) {
60939fb8
NC
674 /* value overflowed.
675 skip the remaining digits, don't
676 worry about setting *valuep. */
677 do {
678 s++;
679 } while (s < send && isDIGIT(*s));
680 numtype |=
681 IS_NUMBER_GREATER_THAN_UV_MAX;
682 goto skip_value;
683 }
684 }
685 }
98994639 686 }
60939fb8
NC
687 }
688 }
689 }
690 }
691 }
692 }
693 }
694 }
695 }
696 }
697 }
98994639 698 }
60939fb8 699 }
98994639 700 }
60939fb8
NC
701 numtype |= IS_NUMBER_IN_UV;
702 if (valuep)
703 *valuep = value;
704
705 skip_value:
706 if (GROK_NUMERIC_RADIX(&s, send)) {
707 numtype |= IS_NUMBER_NOT_INT;
708 while (s < send && isDIGIT(*s)) /* optional digits after the radix */
709 s++;
98994639 710 }
60939fb8
NC
711 }
712 else if (GROK_NUMERIC_RADIX(&s, send)) {
713 numtype |= IS_NUMBER_NOT_INT | IS_NUMBER_IN_UV; /* valuep assigned below */
714 /* no digits before the radix means we need digits after it */
715 if (s < send && isDIGIT(*s)) {
716 do {
717 s++;
718 } while (s < send && isDIGIT(*s));
719 if (valuep) {
720 /* integer approximation is valid - it's 0. */
721 *valuep = 0;
722 }
98994639 723 }
60939fb8
NC
724 else
725 return 0;
726 } else if (*s == 'I' || *s == 'i') {
727 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
728 s++; if (s == send || (*s != 'F' && *s != 'f')) return 0;
729 s++; if (s < send && (*s == 'I' || *s == 'i')) {
730 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
731 s++; if (s == send || (*s != 'I' && *s != 'i')) return 0;
732 s++; if (s == send || (*s != 'T' && *s != 't')) return 0;
733 s++; if (s == send || (*s != 'Y' && *s != 'y')) return 0;
734 s++;
98994639 735 }
60939fb8 736 sawinf = 1;
aa8b85de
JH
737 } else if (*s == 'N' || *s == 'n') {
738 /* XXX TODO: There are signaling NaNs and quiet NaNs. */
739 s++; if (s == send || (*s != 'A' && *s != 'a')) return 0;
740 s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
741 s++;
742 sawnan = 1;
743 } else
98994639 744 return 0;
60939fb8
NC
745
746 if (sawinf) {
747 numtype &= IS_NUMBER_NEG; /* Keep track of sign */
748 numtype |= IS_NUMBER_INFINITY | IS_NUMBER_NOT_INT;
aa8b85de
JH
749 } else if (sawnan) {
750 numtype &= IS_NUMBER_NEG; /* Keep track of sign */
751 numtype |= IS_NUMBER_NAN | IS_NUMBER_NOT_INT;
60939fb8
NC
752 } else if (s < send) {
753 /* we can have an optional exponent part */
754 if (*s == 'e' || *s == 'E') {
60939fb8
NC
755 s++;
756 if (s < send && (*s == '-' || *s == '+'))
757 s++;
758 if (s < send && isDIGIT(*s)) {
759 do {
760 s++;
761 } while (s < send && isDIGIT(*s));
762 }
3f7602fa
TC
763 else if (flags & PERL_SCAN_TRAILING)
764 return numtype | IS_NUMBER_TRAILING;
60939fb8 765 else
3f7602fa
TC
766 return 0;
767
768 /* The only flag we keep is sign. Blow away any "it's UV" */
769 numtype &= IS_NUMBER_NEG;
770 numtype |= IS_NUMBER_NOT_INT;
60939fb8
NC
771 }
772 }
773 while (s < send && isSPACE(*s))
774 s++;
775 if (s >= send)
aa8b85de 776 return numtype;
60939fb8
NC
777 if (len == 10 && memEQ(pv, "0 but true", 10)) {
778 if (valuep)
779 *valuep = 0;
780 return IS_NUMBER_IN_UV;
781 }
3f7602fa
TC
782 else if (flags & PERL_SCAN_TRAILING) {
783 return numtype | IS_NUMBER_TRAILING;
784 }
785
60939fb8 786 return 0;
98994639
HS
787}
788
6313e544
JH
789/*
790=for perlapi
791
792grok_atou is a safer replacement for atoi.
793
794(atoi has severe problems with illegal inputs, and should not be used.
795atoi is also affected by locale settings, which can be seen as a bug.)
796
797Returns the unsigned value, if a valid one can be parsed.
798
799Only the decimal digits '0'..'9' are accepted.
800
801Does NOT allow optional leading whitespace, as opposed to atoi.
802
803On return the *endptr will contain the pointer to the first non-digit byte.
804
805If the value overflows, returns Size_t_MAX, and sets the *endptr
806to NULL, unless endptr is NULL.
807
808If the endptr is NULL, the first non-digit byte MUST be
809the zero byte terminating the pv, or either zero or Size_t_MAX
810will be returned, as appropriate.
811
812=cut
813*/
814
815Size_t
816Perl_grok_atou(const char *pv, const char** endptr)
817{
818 const char* s = pv;
819 const char** eptr;
820 const char* end2; /* Used in case endptr is NULL. */
821 Size_t val = 0; /* The return value. */
822
823 PERL_ARGS_ASSERT_GROK_ATOU;
824
825 eptr = endptr ? endptr : &end2;
826 if (isDIGIT(*s) && !isDIGIT(*(s + 1))) {
827 /* Quite common cases, and in addition the case of zero ("0")
828 * simplifies the decoding loop: not having to think whether
829 * "000" or "000123" are valid (now they are invalid). */
830 val = *s++ - '0';
831 } else {
832 Size_t tmp = 0; /* Temporary accumulator. */
833
834 while (*s) {
835 /* This could be unrolled like in grok_number(), but
836 * the expected uses of this are not speed-needy, and
837 * unlikely to need 64-bitness. */
838 if (isDIGIT(*s)) {
839 int digit = *s++ - '0';
840 tmp = tmp * 10 + digit;
841 if (tmp > val) { /* Rejects leading zeros. */
842 val = tmp;
843 } else { /* Overflow. */
844 *eptr = NULL;
845 return Size_t_MAX;
846 }
847 } else {
848 break;
849 }
850 }
851 if (s == pv) {
852 *eptr = NULL; /* If no progress, failed to parse anything. */
853 return 0;
854 }
855 }
856 if (endptr == NULL && *s) {
857 return 0; /* If endptr is NULL, no trailing non-digits allowed. */
858 }
859 *eptr = s;
860 return val;
861}
862
4801ca72 863STATIC NV
98994639
HS
864S_mulexp10(NV value, I32 exponent)
865{
866 NV result = 1.0;
867 NV power = 10.0;
868 bool negative = 0;
869 I32 bit;
870
871 if (exponent == 0)
872 return value;
659c4b96
DM
873 if (value == 0)
874 return (NV)0;
87032ba1 875
24866caa 876 /* On OpenVMS VAX we by default use the D_FLOAT double format,
67597c89 877 * and that format does not have *easy* capabilities [1] for
24866caa
CB
878 * overflowing doubles 'silently' as IEEE fp does. We also need
879 * to support G_FLOAT on both VAX and Alpha, and though the exponent
880 * range is much larger than D_FLOAT it still doesn't do silent
881 * overflow. Therefore we need to detect early whether we would
882 * overflow (this is the behaviour of the native string-to-float
883 * conversion routines, and therefore of native applications, too).
67597c89 884 *
24866caa
CB
885 * [1] Trying to establish a condition handler to trap floating point
886 * exceptions is not a good idea. */
87032ba1
JH
887
888 /* In UNICOS and in certain Cray models (such as T90) there is no
889 * IEEE fp, and no way at all from C to catch fp overflows gracefully.
890 * There is something you can do if you are willing to use some
891 * inline assembler: the instruction is called DFI-- but that will
892 * disable *all* floating point interrupts, a little bit too large
893 * a hammer. Therefore we need to catch potential overflows before
894 * it's too late. */
353813d9 895
85bba25f 896#if ((defined(VMS) && !defined(_IEEE_FP)) || defined(_UNICOS)) && defined(NV_MAX_10_EXP)
353813d9 897 STMT_START {
c4420975 898 const NV exp_v = log10(value);
353813d9
HS
899 if (exponent >= NV_MAX_10_EXP || exponent + exp_v >= NV_MAX_10_EXP)
900 return NV_MAX;
901 if (exponent < 0) {
902 if (-(exponent + exp_v) >= NV_MAX_10_EXP)
903 return 0.0;
904 while (-exponent >= NV_MAX_10_EXP) {
905 /* combination does not overflow, but 10^(-exponent) does */
906 value /= 10;
907 ++exponent;
908 }
909 }
910 } STMT_END;
87032ba1
JH
911#endif
912
353813d9
HS
913 if (exponent < 0) {
914 negative = 1;
915 exponent = -exponent;
b27804d8
DM
916#ifdef NV_MAX_10_EXP
917 /* for something like 1234 x 10^-309, the action of calculating
918 * the intermediate value 10^309 then returning 1234 / (10^309)
919 * will fail, since 10^309 becomes infinity. In this case try to
920 * refactor it as 123 / (10^308) etc.
921 */
922 while (value && exponent > NV_MAX_10_EXP) {
923 exponent--;
924 value /= 10;
925 }
926#endif
353813d9 927 }
98994639
HS
928 for (bit = 1; exponent; bit <<= 1) {
929 if (exponent & bit) {
930 exponent ^= bit;
931 result *= power;
236f0012
CB
932 /* Floating point exceptions are supposed to be turned off,
933 * but if we're obviously done, don't risk another iteration.
934 */
935 if (exponent == 0) break;
98994639
HS
936 }
937 power *= power;
938 }
939 return negative ? value / result : value * result;
940}
941
942NV
943Perl_my_atof(pTHX_ const char* s)
944{
945 NV x = 0.0;
946#ifdef USE_LOCALE_NUMERIC
7918f24d
NC
947 PERL_ARGS_ASSERT_MY_ATOF;
948
a2287a13
KW
949 {
950 DECLARE_STORE_LC_NUMERIC_SET_TO_NEEDED();
d6ded950 951 if (PL_numeric_radix_sv && IN_LC(LC_NUMERIC)) {
e4850248
KW
952 const char *standard = NULL, *local = NULL;
953 bool use_standard_radix;
98994639 954
e4850248
KW
955 /* Look through the string for the first thing that looks like a
956 * decimal point: either the value in the current locale or the
957 * standard fallback of '.'. The one which appears earliest in the
958 * input string is the one that we should have atof look for. Note
959 * that we have to determine this beforehand because on some
960 * systems, Perl_atof2 is just a wrapper around the system's atof.
961 * */
962 standard = strchr(s, '.');
963 local = strstr(s, SvPV_nolen(PL_numeric_radix_sv));
78787052 964
e4850248 965 use_standard_radix = standard && (!local || standard < local);
78787052 966
e4850248
KW
967 if (use_standard_radix)
968 SET_NUMERIC_STANDARD();
78787052 969
e4850248 970 Perl_atof2(s, x);
78787052 971
e4850248
KW
972 if (use_standard_radix)
973 SET_NUMERIC_LOCAL();
974 }
975 else
976 Perl_atof2(s, x);
a2287a13
KW
977 RESTORE_LC_NUMERIC();
978 }
98994639 979#else
a36244b7 980 Perl_atof2(s, x);
98994639
HS
981#endif
982 return x;
983}
984
985char*
986Perl_my_atof2(pTHX_ const char* orig, NV* value)
987{
20f6aaab 988 NV result[3] = {0.0, 0.0, 0.0};
e1ec3a88 989 const char* s = orig;
a36244b7 990#ifdef USE_PERL_ATOF
20f6aaab 991 UV accumulator[2] = {0,0}; /* before/after dp */
a36244b7 992 bool negative = 0;
e1ec3a88 993 const char* send = s + strlen(orig) - 1;
8194bf88 994 bool seen_digit = 0;
20f6aaab
AS
995 I32 exp_adjust[2] = {0,0};
996 I32 exp_acc[2] = {-1, -1};
997 /* the current exponent adjust for the accumulators */
98994639 998 I32 exponent = 0;
8194bf88 999 I32 seen_dp = 0;
20f6aaab
AS
1000 I32 digit = 0;
1001 I32 old_digit = 0;
8194bf88
DM
1002 I32 sig_digits = 0; /* noof significant digits seen so far */
1003
7918f24d
NC
1004 PERL_ARGS_ASSERT_MY_ATOF2;
1005
8194bf88
DM
1006/* There is no point in processing more significant digits
1007 * than the NV can hold. Note that NV_DIG is a lower-bound value,
1008 * while we need an upper-bound value. We add 2 to account for this;
1009 * since it will have been conservative on both the first and last digit.
1010 * For example a 32-bit mantissa with an exponent of 4 would have
1011 * exact values in the set
1012 * 4
1013 * 8
1014 * ..
1015 * 17179869172
1016 * 17179869176
1017 * 17179869180
1018 *
1019 * where for the purposes of calculating NV_DIG we would have to discount
1020 * both the first and last digit, since neither can hold all values from
1021 * 0..9; but for calculating the value we must examine those two digits.
1022 */
ffa277e5
EAS
1023#ifdef MAX_SIG_DIG_PLUS
1024 /* It is not necessarily the case that adding 2 to NV_DIG gets all the
1025 possible digits in a NV, especially if NVs are not IEEE compliant
1026 (e.g., long doubles on IRIX) - Allen <allens@cpan.org> */
1027# define MAX_SIG_DIGITS (NV_DIG+MAX_SIG_DIG_PLUS)
1028#else
1029# define MAX_SIG_DIGITS (NV_DIG+2)
1030#endif
8194bf88
DM
1031
1032/* the max number we can accumulate in a UV, and still safely do 10*N+9 */
1033#define MAX_ACCUMULATE ( (UV) ((UV_MAX - 9)/10))
98994639 1034
96a05aee
HS
1035 /* leading whitespace */
1036 while (isSPACE(*s))
1037 ++s;
1038
98994639
HS
1039 /* sign */
1040 switch (*s) {
1041 case '-':
1042 negative = 1;
924ba076 1043 /* FALLTHROUGH */
98994639
HS
1044 case '+':
1045 ++s;
1046 }
1047
2b54f59f
YST
1048 /* punt to strtod for NaN/Inf; if no support for it there, tough luck */
1049
1050#ifdef HAS_STRTOD
1051 if (*s == 'n' || *s == 'N' || *s == 'i' || *s == 'I') {
c042ae3a 1052 const char *p = negative ? s - 1 : s;
2b54f59f
YST
1053 char *endp;
1054 NV rslt;
1055 rslt = strtod(p, &endp);
1056 if (endp != p) {
1057 *value = rslt;
1058 return (char *)endp;
1059 }
1060 }
1061#endif
1062
8194bf88
DM
1063 /* we accumulate digits into an integer; when this becomes too
1064 * large, we add the total to NV and start again */
98994639 1065
8194bf88
DM
1066 while (1) {
1067 if (isDIGIT(*s)) {
1068 seen_digit = 1;
20f6aaab 1069 old_digit = digit;
8194bf88 1070 digit = *s++ - '0';
20f6aaab
AS
1071 if (seen_dp)
1072 exp_adjust[1]++;
98994639 1073
8194bf88
DM
1074 /* don't start counting until we see the first significant
1075 * digit, eg the 5 in 0.00005... */
1076 if (!sig_digits && digit == 0)
1077 continue;
1078
1079 if (++sig_digits > MAX_SIG_DIGITS) {
98994639 1080 /* limits of precision reached */
20f6aaab
AS
1081 if (digit > 5) {
1082 ++accumulator[seen_dp];
1083 } else if (digit == 5) {
1084 if (old_digit % 2) { /* round to even - Allen */
1085 ++accumulator[seen_dp];
1086 }
1087 }
1088 if (seen_dp) {
1089 exp_adjust[1]--;
1090 } else {
1091 exp_adjust[0]++;
1092 }
8194bf88 1093 /* skip remaining digits */
98994639 1094 while (isDIGIT(*s)) {
98994639 1095 ++s;
20f6aaab
AS
1096 if (! seen_dp) {
1097 exp_adjust[0]++;
1098 }
98994639
HS
1099 }
1100 /* warn of loss of precision? */
98994639 1101 }
8194bf88 1102 else {
20f6aaab 1103 if (accumulator[seen_dp] > MAX_ACCUMULATE) {
8194bf88 1104 /* add accumulator to result and start again */
20f6aaab
AS
1105 result[seen_dp] = S_mulexp10(result[seen_dp],
1106 exp_acc[seen_dp])
1107 + (NV)accumulator[seen_dp];
1108 accumulator[seen_dp] = 0;
1109 exp_acc[seen_dp] = 0;
98994639 1110 }
20f6aaab
AS
1111 accumulator[seen_dp] = accumulator[seen_dp] * 10 + digit;
1112 ++exp_acc[seen_dp];
98994639 1113 }
8194bf88 1114 }
e1ec3a88 1115 else if (!seen_dp && GROK_NUMERIC_RADIX(&s, send)) {
8194bf88 1116 seen_dp = 1;
20f6aaab 1117 if (sig_digits > MAX_SIG_DIGITS) {
c86f7df5 1118 do {
20f6aaab 1119 ++s;
c86f7df5 1120 } while (isDIGIT(*s));
20f6aaab
AS
1121 break;
1122 }
8194bf88
DM
1123 }
1124 else {
1125 break;
98994639
HS
1126 }
1127 }
1128
20f6aaab
AS
1129 result[0] = S_mulexp10(result[0], exp_acc[0]) + (NV)accumulator[0];
1130 if (seen_dp) {
1131 result[1] = S_mulexp10(result[1], exp_acc[1]) + (NV)accumulator[1];
1132 }
98994639 1133
8194bf88 1134 if (seen_digit && (*s == 'e' || *s == 'E')) {
98994639
HS
1135 bool expnegative = 0;
1136
1137 ++s;
1138 switch (*s) {
1139 case '-':
1140 expnegative = 1;
924ba076 1141 /* FALLTHROUGH */
98994639
HS
1142 case '+':
1143 ++s;
1144 }
1145 while (isDIGIT(*s))
1146 exponent = exponent * 10 + (*s++ - '0');
1147 if (expnegative)
1148 exponent = -exponent;
1149 }
1150
20f6aaab
AS
1151
1152
98994639 1153 /* now apply the exponent */
20f6aaab
AS
1154
1155 if (seen_dp) {
1156 result[2] = S_mulexp10(result[0],exponent+exp_adjust[0])
1157 + S_mulexp10(result[1],exponent-exp_adjust[1]);
1158 } else {
1159 result[2] = S_mulexp10(result[0],exponent+exp_adjust[0]);
1160 }
98994639
HS
1161
1162 /* now apply the sign */
1163 if (negative)
20f6aaab 1164 result[2] = -result[2];
a36244b7 1165#endif /* USE_PERL_ATOF */
20f6aaab 1166 *value = result[2];
73d840c0 1167 return (char *)s;
98994639
HS
1168}
1169
55954f19
JH
1170#if ! defined(HAS_MODFL) && defined(HAS_AINTL) && defined(HAS_COPYSIGNL)
1171long double
1172Perl_my_modfl(long double x, long double *ip)
1173{
1174 *ip = aintl(x);
1175 return (x == *ip ? copysignl(0.0L, x) : x - *ip);
1176}
1177#endif
1178
1179#if ! defined(HAS_FREXPL) && defined(HAS_ILOGBL) && defined(HAS_SCALBNL)
1180long double
1181Perl_my_frexpl(long double x, int *e) {
1182 *e = x == 0.0L ? 0 : ilogbl(x) + 1;
1183 return (scalbnl(x, -*e));
1184}
1185#endif
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RGS
1186
1187/*
ed140128
AD
1188=for apidoc Perl_signbit
1189
1190Return a non-zero integer if the sign bit on an NV is set, and 0 if
1191it is not.
1192
1193If Configure detects this system has a signbit() that will work with
1194our NVs, then we just use it via the #define in perl.h. Otherwise,
1195fall back on this implementation. As a first pass, this gets everything
1196right except -0.0. Alas, catching -0.0 is the main use for this function,
1197so this is not too helpful yet. Still, at least we have the scaffolding
1198in place to support other systems, should that prove useful.
1199
1200
1201Configure notes: This function is called 'Perl_signbit' instead of a
1202plain 'signbit' because it is easy to imagine a system having a signbit()
1203function or macro that doesn't happen to work with our particular choice
1204of NVs. We shouldn't just re-#define signbit as Perl_signbit and expect
1205the standard system headers to be happy. Also, this is a no-context
1206function (no pTHX_) because Perl_signbit() is usually re-#defined in
1207perl.h as a simple macro call to the system's signbit().
1208Users should just always call Perl_signbit().
1209
1210=cut
1211*/
1212#if !defined(HAS_SIGNBIT)
1213int
1214Perl_signbit(NV x) {
1215 return (x < 0.0) ? 1 : 0;
1216}
1217#endif
1218
1219/*
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RGS
1220 * Local variables:
1221 * c-indentation-style: bsd
1222 * c-basic-offset: 4
14d04a33 1223 * indent-tabs-mode: nil
66610fdd
RGS
1224 * End:
1225 *
14d04a33 1226 * ex: set ts=8 sts=4 sw=4 et:
37442d52 1227 */