/* numeric.c
*
- * Copyright (c) 2001, Larry Wall
+ * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
+ * 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
*
* You may distribute under the terms of either the GNU General Public
* License or the Artistic License, as specified in the README file.
*/
/*
- * "That only makes eleven (plus one mislaid) and not fourteen, unless
- * wizards count differently to other people."
+ * "That only makes eleven (plus one mislaid) and not fourteen,
+ * unless wizards count differently to other people." --Beorn
+ *
+ * [p.115 of _The Hobbit_: "Queer Lodgings"]
*/
+/*
+=head1 Numeric functions
+
+=cut
+
+This file contains all the stuff needed by perl for manipulating numeric
+values, including such things as replacements for the OS's atof() function
+
+*/
+
#include "EXTERN.h"
#define PERL_IN_NUMERIC_C
#include "perl.h"
+#ifdef Perl_strtod
+
+PERL_STATIC_INLINE NV
+S_strtod(pTHX_ const char * const s, char ** e)
+{
+ DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
+ NV result;
+
+ STORE_LC_NUMERIC_SET_TO_NEEDED();
+
+# ifdef USE_QUADMATH
+
+ result = strtoflt128(s, e);
+
+# elif defined(HAS_STRTOLD) && defined(HAS_LONG_DOUBLE) \
+ && defined(USE_LONG_DOUBLE)
+# if defined(__MINGW64_VERSION_MAJOR)
+ /***********************************************
+ We are unable to use strtold because of
+ https://sourceforge.net/p/mingw-w64/bugs/711/
+ &
+ https://sourceforge.net/p/mingw-w64/bugs/725/
+
+ but __mingw_strtold is fine.
+ ***********************************************/
+
+ result = __mingw_strtold(s, e);
+
+# else
+
+ result = strtold(s, e);
+
+# endif
+# elif defined(HAS_STRTOD)
+
+ result = strtod(s, e);
+
+# else
+# error No strtod() equivalent found
+# endif
+
+ RESTORE_LC_NUMERIC();
+
+ return result;
+}
+
+#endif /* #ifdef Perl_strtod */
+
+/*
+
+=for apidoc my_strtod
+
+This function is equivalent to the libc strtod() function, and is available
+even on platforms that lack plain strtod(). Its return value is the best
+available precision depending on platform capabilities and F<Configure>
+options.
+
+It properly handles the locale radix character, meaning it expects a dot except
+when called from within the scope of S<C<use locale>>, in which case the radix
+character should be that specified by the current locale.
+
+The synonym Strtod() may be used instead.
+
+=cut
+
+*/
+
+NV
+Perl_my_strtod(const char * const s, char **e)
+{
+ dTHX;
+
+ PERL_ARGS_ASSERT_MY_STRTOD;
+
+#ifdef Perl_strtod
+
+ return S_strtod(aTHX_ s, e);
+
+#else
+
+ {
+ NV result;
+ char ** end_ptr = NULL;
+
+ *end_ptr = my_atof2(s, &result);
+ if (e) {
+ *e = *end_ptr;
+ }
+
+ if (! *end_ptr) {
+ result = 0.0;
+ }
+
+ return result;
+ }
+
+#endif
+
+}
+
+
U32
-Perl_cast_ulong(pTHX_ NV f)
+Perl_cast_ulong(NV f)
{
if (f < 0.0)
return f < I32_MIN ? (U32) I32_MIN : (U32)(I32) f;
if (f < U32_MAX_P1_HALF)
return (U32) f;
f -= U32_MAX_P1_HALF;
- return ((U32) f) | (1 + U32_MAX >> 1);
+ return ((U32) f) | (1 + (U32_MAX >> 1));
#else
return (U32) f;
#endif
}
I32
-Perl_cast_i32(pTHX_ NV f)
+Perl_cast_i32(NV f)
{
if (f < I32_MAX_P1)
return f < I32_MIN ? I32_MIN : (I32) f;
if (f < U32_MAX_P1_HALF)
return (I32)(U32) f;
f -= U32_MAX_P1_HALF;
- return (I32)(((U32) f) | (1 + U32_MAX >> 1));
+ return (I32)(((U32) f) | (1 + (U32_MAX >> 1)));
#else
return (I32)(U32) f;
#endif
}
IV
-Perl_cast_iv(pTHX_ NV f)
+Perl_cast_iv(NV f)
{
if (f < IV_MAX_P1)
return f < IV_MIN ? IV_MIN : (IV) f;
if (f < UV_MAX_P1_HALF)
return (IV)(UV) f;
f -= UV_MAX_P1_HALF;
- return (IV)(((UV) f) | (1 + UV_MAX >> 1));
+ return (IV)(((UV) f) | (1 + (UV_MAX >> 1)));
#else
return (IV)(UV) f;
#endif
}
UV
-Perl_cast_uv(pTHX_ NV f)
+Perl_cast_uv(NV f)
{
if (f < 0.0)
return f < IV_MIN ? (UV) IV_MIN : (UV)(IV) f;
if (f < UV_MAX_P1_HALF)
return (UV) f;
f -= UV_MAX_P1_HALF;
- return ((UV) f) | (1 + UV_MAX >> 1);
+ return ((UV) f) | (1 + (UV_MAX >> 1));
#else
return (UV) f;
#endif
return f > 0 ? UV_MAX : 0 /* NaN */;
}
-#if defined(HUGE_VAL) || (defined(USE_LONG_DOUBLE) && defined(HUGE_VALL))
/*
- * This hack is to force load of "huge" support from libm.a
- * So it is in perl for (say) POSIX to use.
- * Needed for SunOS with Sun's 'acc' for example.
+=for apidoc grok_bin
+
+converts a string representing a binary number to numeric form.
+
+On entry C<start> and C<*len> give the string to scan, C<*flags> gives
+conversion flags, and C<result> should be C<NULL> or a pointer to an NV.
+The scan stops at the end of the string, or the first invalid character.
+Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in C<*flags>, encountering an
+invalid character will also trigger a warning.
+On return C<*len> is set to the length of the scanned string,
+and C<*flags> gives output flags.
+
+If the value is <= C<UV_MAX> it is returned as a UV, the output flags are clear,
+and nothing is written to C<*result>. If the value is > C<UV_MAX>, C<grok_bin>
+returns C<UV_MAX>, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
+and writes the value to C<*result> (or the value is discarded if C<result>
+is NULL).
+
+The binary number may optionally be prefixed with C<"0b"> or C<"b"> unless
+C<PERL_SCAN_DISALLOW_PREFIX> is set in C<*flags> on entry. If
+C<PERL_SCAN_ALLOW_UNDERSCORES> is set in C<*flags> then the binary
+number may use C<"_"> characters to separate digits.
+
+=for apidoc Amnh||PERL_SCAN_ALLOW_UNDERSCORES
+=for apidoc Amnh||PERL_SCAN_DISALLOW_PREFIX
+=for apidoc Amnh||PERL_SCAN_GREATER_THAN_UV_MAX
+=for apidoc Amnh||PERL_SCAN_SILENT_ILLDIGIT
+=for apidoc Amnh||PERL_SCAN_TRAILING
+
+=cut
+
+Not documented yet because experimental is C<PERL_SCAN_SILENT_NON_PORTABLE
+which suppresses any message for non-portable numbers that are still valid
+on this platform.
*/
-NV
-Perl_huge(void)
-{
-# if defined(USE_LONG_DOUBLE) && defined(HUGE_VALL)
- return HUGE_VALL;
-# endif
- return HUGE_VAL;
-}
-#endif
-NV
-Perl_scan_bin(pTHX_ char *start, STRLEN len, STRLEN *retlen)
+UV
+Perl_grok_bin(pTHX_ const char *start, STRLEN *len_p, I32 *flags, NV *result)
{
- register char *s = start;
- register NV rnv = 0.0;
- register UV ruv = 0;
- register bool seenb = FALSE;
- register bool overflowed = FALSE;
+ const char *s = start;
+ STRLEN len = *len_p;
+ UV value = 0;
+ NV value_nv = 0;
- for (; len-- && *s; s++) {
- if (!(*s == '0' || *s == '1')) {
- if (*s == '_' && len && *retlen
- && (s[1] == '0' || s[1] == '1'))
- {
- --len;
- ++s;
- }
- else if (seenb == FALSE && *s == 'b' && ruv == 0) {
- /* Disallow 0bbb0b0bbb... */
- seenb = TRUE;
- continue;
- }
- else {
- if (ckWARN(WARN_DIGIT))
- Perl_warner(aTHX_ WARN_DIGIT,
- "Illegal binary digit '%c' ignored", *s);
- break;
- }
- }
- if (!overflowed) {
- register UV xuv = ruv << 1;
-
- if ((xuv >> 1) != ruv) {
- overflowed = TRUE;
- rnv = (NV) ruv;
- if (ckWARN_d(WARN_OVERFLOW))
- Perl_warner(aTHX_ WARN_OVERFLOW,
- "Integer overflow in binary number");
- }
- else
- ruv = xuv | (*s - '0');
- }
- if (overflowed) {
- rnv *= 2;
+ const UV max_div_2 = UV_MAX / 2;
+ const bool allow_underscores = cBOOL(*flags & PERL_SCAN_ALLOW_UNDERSCORES);
+ bool overflowed = FALSE;
+ char bit;
+
+ PERL_ARGS_ASSERT_GROK_BIN;
+
+ if (!(*flags & PERL_SCAN_DISALLOW_PREFIX)) {
+ /* strip off leading b or 0b.
+ for compatibility silently suffer "b" and "0b" as valid binary
+ numbers. */
+ if (len >= 1) {
+ if (isALPHA_FOLD_EQ(s[0], 'b')) {
+ s++;
+ len--;
+ }
+ else if (len >= 2 && s[0] == '0' && (isALPHA_FOLD_EQ(s[1], 'b'))) {
+ s+=2;
+ len-=2;
+ }
+ }
+ }
+
+ for (; len-- && (bit = *s); s++) {
+ if (bit == '0' || bit == '1') {
+ /* Write it in this wonky order with a goto to attempt to get the
+ compiler to make the common case integer-only loop pretty tight.
+ With gcc seems to be much straighter code than old scan_bin. */
+ redo:
+ if (!overflowed) {
+ if (value <= max_div_2) {
+ value = (value << 1) | (bit - '0');
+ continue;
+ }
+ /* Bah. We're just overflowed. */
+ /* diag_listed_as: Integer overflow in %s number */
+ Perl_ck_warner_d(aTHX_ packWARN(WARN_OVERFLOW),
+ "Integer overflow in binary number");
+ overflowed = TRUE;
+ value_nv = (NV) value;
+ }
+ value_nv *= 2.0;
/* If an NV has not enough bits in its mantissa to
- * represent an UV this summing of small low-order numbers
+ * represent a UV this summing of small low-order numbers
* is a waste of time (because the NV cannot preserve
* the low-order bits anyway): we could just remember when
- * did we overflow and in the end just multiply rnv by the
+ * did we overflow and in the end just multiply value_nv by the
* right amount. */
- rnv += (*s - '0');
- }
+ value_nv += (NV)(bit - '0');
+ continue;
+ }
+ if (bit == '_' && len && allow_underscores && (bit = s[1])
+ && (bit == '0' || bit == '1'))
+ {
+ --len;
+ ++s;
+ goto redo;
+ }
+ if (!(*flags & PERL_SCAN_SILENT_ILLDIGIT))
+ Perl_ck_warner(aTHX_ packWARN(WARN_DIGIT),
+ "Illegal binary digit '%c' ignored", *s);
+ break;
}
- if (!overflowed)
- rnv = (NV) ruv;
- if ( ( overflowed && rnv > 4294967295.0)
+
+ if ( ( overflowed && value_nv > 4294967295.0)
#if UVSIZE > 4
- || (!overflowed && ruv > 0xffffffff )
+ || (!overflowed && value > 0xffffffff
+ && ! (*flags & PERL_SCAN_SILENT_NON_PORTABLE))
#endif
) {
- if (ckWARN(WARN_PORTABLE))
- Perl_warner(aTHX_ WARN_PORTABLE,
- "Binary number > 0b11111111111111111111111111111111 non-portable");
+ Perl_ck_warner(aTHX_ packWARN(WARN_PORTABLE),
+ "Binary number > 0b11111111111111111111111111111111 non-portable");
}
- *retlen = s - start;
- return rnv;
+ *len_p = s - start;
+ if (!overflowed) {
+ *flags = 0;
+ return value;
+ }
+ *flags = PERL_SCAN_GREATER_THAN_UV_MAX;
+ if (result)
+ *result = value_nv;
+ return UV_MAX;
}
-NV
-Perl_scan_oct(pTHX_ char *start, STRLEN len, STRLEN *retlen)
+/*
+=for apidoc grok_hex
+
+converts a string representing a hex number to numeric form.
+
+On entry C<start> and C<*len_p> give the string to scan, C<*flags> gives
+conversion flags, and C<result> should be C<NULL> or a pointer to an NV.
+The scan stops at the end of the string, or the first invalid character.
+Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in C<*flags>, encountering an
+invalid character will also trigger a warning.
+On return C<*len> is set to the length of the scanned string,
+and C<*flags> gives output flags.
+
+If the value is <= C<UV_MAX> it is returned as a UV, the output flags are clear,
+and nothing is written to C<*result>. If the value is > C<UV_MAX>, C<grok_hex>
+returns C<UV_MAX>, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
+and writes the value to C<*result> (or the value is discarded if C<result>
+is C<NULL>).
+
+The hex number may optionally be prefixed with C<"0x"> or C<"x"> unless
+C<PERL_SCAN_DISALLOW_PREFIX> is set in C<*flags> on entry. If
+C<PERL_SCAN_ALLOW_UNDERSCORES> is set in C<*flags> then the hex
+number may use C<"_"> characters to separate digits.
+
+=cut
+
+Not documented yet because experimental is C<PERL_SCAN_SILENT_NON_PORTABLE
+which suppresses any message for non-portable numbers, but which are valid
+on this platform.
+ */
+
+UV
+Perl_grok_hex(pTHX_ const char *start, STRLEN *len_p, I32 *flags, NV *result)
{
- register char *s = start;
- register NV rnv = 0.0;
- register UV ruv = 0;
- register bool overflowed = FALSE;
+ const char *s = start;
+ STRLEN len = *len_p;
+ UV value = 0;
+ NV value_nv = 0;
+ const UV max_div_16 = UV_MAX / 16;
+ const bool allow_underscores = cBOOL(*flags & PERL_SCAN_ALLOW_UNDERSCORES);
+ bool overflowed = FALSE;
+
+ PERL_ARGS_ASSERT_GROK_HEX;
+
+ if (!(*flags & PERL_SCAN_DISALLOW_PREFIX)) {
+ /* strip off leading x or 0x.
+ for compatibility silently suffer "x" and "0x" as valid hex numbers.
+ */
+ if (len >= 1) {
+ if (isALPHA_FOLD_EQ(s[0], 'x')) {
+ s++;
+ len--;
+ }
+ else if (len >= 2 && s[0] == '0' && (isALPHA_FOLD_EQ(s[1], 'x'))) {
+ s+=2;
+ len-=2;
+ }
+ }
+ }
for (; len-- && *s; s++) {
- if (!(*s >= '0' && *s <= '7')) {
- if (*s == '_' && len && *retlen
- && (s[1] >= '0' && s[1] <= '7'))
+ if (isXDIGIT(*s)) {
+ /* Write it in this wonky order with a goto to attempt to get the
+ compiler to make the common case integer-only loop pretty tight.
+ With gcc seems to be much straighter code than old scan_hex. */
+ redo:
+ if (!overflowed) {
+ if (value <= max_div_16) {
+ value = (value << 4) | XDIGIT_VALUE(*s);
+ continue;
+ }
+ /* Bah. We're just overflowed. */
+ /* diag_listed_as: Integer overflow in %s number */
+ Perl_ck_warner_d(aTHX_ packWARN(WARN_OVERFLOW),
+ "Integer overflow in hexadecimal number");
+ overflowed = TRUE;
+ value_nv = (NV) value;
+ }
+ value_nv *= 16.0;
+ /* If an NV has not enough bits in its mantissa to
+ * represent a UV this summing of small low-order numbers
+ * is a waste of time (because the NV cannot preserve
+ * the low-order bits anyway): we could just remember when
+ * did we overflow and in the end just multiply value_nv by the
+ * right amount of 16-tuples. */
+ value_nv += (NV) XDIGIT_VALUE(*s);
+ continue;
+ }
+ if (*s == '_' && len && allow_underscores && s[1]
+ && isXDIGIT(s[1]))
{
--len;
++s;
+ goto redo;
}
- else {
- /* Allow \octal to work the DWIM way (that is, stop scanning
- * as soon as non-octal characters are seen, complain only iff
- * someone seems to want to use the digits eight and nine). */
- if (*s == '8' || *s == '9') {
- if (ckWARN(WARN_DIGIT))
- Perl_warner(aTHX_ WARN_DIGIT,
- "Illegal octal digit '%c' ignored", *s);
- }
- break;
- }
- }
- if (!overflowed) {
- register UV xuv = ruv << 3;
-
- if ((xuv >> 3) != ruv) {
- overflowed = TRUE;
- rnv = (NV) ruv;
- if (ckWARN_d(WARN_OVERFLOW))
- Perl_warner(aTHX_ WARN_OVERFLOW,
- "Integer overflow in octal number");
- }
- else
- ruv = xuv | (*s - '0');
- }
- if (overflowed) {
- rnv *= 8.0;
- /* If an NV has not enough bits in its mantissa to
- * represent an UV this summing of small low-order numbers
- * is a waste of time (because the NV cannot preserve
- * the low-order bits anyway): we could just remember when
- * did we overflow and in the end just multiply rnv by the
- * right amount of 8-tuples. */
- rnv += (NV)(*s - '0');
- }
+ if (!(*flags & PERL_SCAN_SILENT_ILLDIGIT))
+ Perl_ck_warner(aTHX_ packWARN(WARN_DIGIT),
+ "Illegal hexadecimal digit '%c' ignored", *s);
+ break;
}
- if (!overflowed)
- rnv = (NV) ruv;
- if ( ( overflowed && rnv > 4294967295.0)
+
+ if ( ( overflowed && value_nv > 4294967295.0)
#if UVSIZE > 4
- || (!overflowed && ruv > 0xffffffff )
+ || (!overflowed && value > 0xffffffff
+ && ! (*flags & PERL_SCAN_SILENT_NON_PORTABLE))
#endif
) {
- if (ckWARN(WARN_PORTABLE))
- Perl_warner(aTHX_ WARN_PORTABLE,
- "Octal number > 037777777777 non-portable");
+ Perl_ck_warner(aTHX_ packWARN(WARN_PORTABLE),
+ "Hexadecimal number > 0xffffffff non-portable");
+ }
+ *len_p = s - start;
+ if (!overflowed) {
+ *flags = 0;
+ return value;
}
- *retlen = s - start;
- return rnv;
+ *flags = PERL_SCAN_GREATER_THAN_UV_MAX;
+ if (result)
+ *result = value_nv;
+ return UV_MAX;
}
-NV
-Perl_scan_hex(pTHX_ char *start, STRLEN len, STRLEN *retlen)
+/*
+=for apidoc grok_oct
+
+converts a string representing an octal number to numeric form.
+
+On entry C<start> and C<*len> give the string to scan, C<*flags> gives
+conversion flags, and C<result> should be C<NULL> or a pointer to an NV.
+The scan stops at the end of the string, or the first invalid character.
+Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in C<*flags>, encountering an
+8 or 9 will also trigger a warning.
+On return C<*len> is set to the length of the scanned string,
+and C<*flags> gives output flags.
+
+If the value is <= C<UV_MAX> it is returned as a UV, the output flags are clear,
+and nothing is written to C<*result>. If the value is > C<UV_MAX>, C<grok_oct>
+returns C<UV_MAX>, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
+and writes the value to C<*result> (or the value is discarded if C<result>
+is C<NULL>).
+
+If C<PERL_SCAN_ALLOW_UNDERSCORES> is set in C<*flags> then the octal
+number may use C<"_"> characters to separate digits.
+
+=cut
+
+Not documented yet because experimental is C<PERL_SCAN_SILENT_NON_PORTABLE>
+which suppresses any message for non-portable numbers, but which are valid
+on this platform.
+ */
+
+UV
+Perl_grok_oct(pTHX_ const char *start, STRLEN *len_p, I32 *flags, NV *result)
{
- register char *s = start;
- register NV rnv = 0.0;
- register UV ruv = 0;
- register bool overflowed = FALSE;
- char *hexdigit;
-
- if (len > 2) {
- if (s[0] == 'x') {
- s++;
- len--;
- }
- else if (len > 3 && s[0] == '0' && s[1] == 'x') {
- s+=2;
- len-=2;
- }
- }
+ const char *s = start;
+ STRLEN len = *len_p;
+ UV value = 0;
+ NV value_nv = 0;
+ const UV max_div_8 = UV_MAX / 8;
+ const bool allow_underscores = cBOOL(*flags & PERL_SCAN_ALLOW_UNDERSCORES);
+ bool overflowed = FALSE;
+
+ PERL_ARGS_ASSERT_GROK_OCT;
for (; len-- && *s; s++) {
- hexdigit = strchr((char *) PL_hexdigit, *s);
- if (!hexdigit) {
- if (*s == '_' && len && *retlen && s[1]
- && (hexdigit = strchr((char *) PL_hexdigit, s[1])))
- {
- --len;
- ++s;
- }
- else {
- if (ckWARN(WARN_DIGIT))
- Perl_warner(aTHX_ WARN_DIGIT,
- "Illegal hexadecimal digit '%c' ignored", *s);
- break;
- }
- }
- if (!overflowed) {
- register UV xuv = ruv << 4;
-
- if ((xuv >> 4) != ruv) {
- overflowed = TRUE;
- rnv = (NV) ruv;
- if (ckWARN_d(WARN_OVERFLOW))
- Perl_warner(aTHX_ WARN_OVERFLOW,
- "Integer overflow in hexadecimal number");
- }
- else
- ruv = xuv | ((hexdigit - PL_hexdigit) & 15);
- }
- if (overflowed) {
- rnv *= 16.0;
+ if (isOCTAL(*s)) {
+ /* Write it in this wonky order with a goto to attempt to get the
+ compiler to make the common case integer-only loop pretty tight.
+ */
+ redo:
+ if (!overflowed) {
+ if (value <= max_div_8) {
+ value = (value << 3) | OCTAL_VALUE(*s);
+ continue;
+ }
+ /* Bah. We're just overflowed. */
+ /* diag_listed_as: Integer overflow in %s number */
+ Perl_ck_warner_d(aTHX_ packWARN(WARN_OVERFLOW),
+ "Integer overflow in octal number");
+ overflowed = TRUE;
+ value_nv = (NV) value;
+ }
+ value_nv *= 8.0;
/* If an NV has not enough bits in its mantissa to
- * represent an UV this summing of small low-order numbers
+ * represent a UV this summing of small low-order numbers
* is a waste of time (because the NV cannot preserve
* the low-order bits anyway): we could just remember when
- * did we overflow and in the end just multiply rnv by the
- * right amount of 16-tuples. */
- rnv += (NV)((hexdigit - PL_hexdigit) & 15);
- }
+ * did we overflow and in the end just multiply value_nv by the
+ * right amount of 8-tuples. */
+ value_nv += (NV) OCTAL_VALUE(*s);
+ continue;
+ }
+ if (*s == '_' && len && allow_underscores && isOCTAL(s[1])) {
+ --len;
+ ++s;
+ goto redo;
+ }
+ /* Allow \octal to work the DWIM way (that is, stop scanning
+ * as soon as non-octal characters are seen, complain only if
+ * someone seems to want to use the digits eight and nine. Since we
+ * know it is not octal, then if isDIGIT, must be an 8 or 9). */
+ if (isDIGIT(*s)) {
+ if (!(*flags & PERL_SCAN_SILENT_ILLDIGIT))
+ Perl_ck_warner(aTHX_ packWARN(WARN_DIGIT),
+ "Illegal octal digit '%c' ignored", *s);
+ }
+ break;
}
- if (!overflowed)
- rnv = (NV) ruv;
- if ( ( overflowed && rnv > 4294967295.0)
+
+ if ( ( overflowed && value_nv > 4294967295.0)
#if UVSIZE > 4
- || (!overflowed && ruv > 0xffffffff )
+ || (!overflowed && value > 0xffffffff
+ && ! (*flags & PERL_SCAN_SILENT_NON_PORTABLE))
#endif
) {
- if (ckWARN(WARN_PORTABLE))
- Perl_warner(aTHX_ WARN_PORTABLE,
- "Hexadecimal number > 0xffffffff non-portable");
+ Perl_ck_warner(aTHX_ packWARN(WARN_PORTABLE),
+ "Octal number > 037777777777 non-portable");
}
- *retlen = s - start;
- return rnv;
+ *len_p = s - start;
+ if (!overflowed) {
+ *flags = 0;
+ return value;
+ }
+ *flags = PERL_SCAN_GREATER_THAN_UV_MAX;
+ if (result)
+ *result = value_nv;
+ return UV_MAX;
+}
+
+/*
+=for apidoc scan_bin
+
+For backwards compatibility. Use C<grok_bin> instead.
+
+=for apidoc scan_hex
+
+For backwards compatibility. Use C<grok_hex> instead.
+
+=for apidoc scan_oct
+
+For backwards compatibility. Use C<grok_oct> instead.
+
+=cut
+ */
+
+NV
+Perl_scan_bin(pTHX_ const char *start, STRLEN len, STRLEN *retlen)
+{
+ NV rnv;
+ I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0;
+ const UV ruv = grok_bin (start, &len, &flags, &rnv);
+
+ PERL_ARGS_ASSERT_SCAN_BIN;
+
+ *retlen = len;
+ return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv;
+}
+
+NV
+Perl_scan_oct(pTHX_ const char *start, STRLEN len, STRLEN *retlen)
+{
+ NV rnv;
+ I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0;
+ const UV ruv = grok_oct (start, &len, &flags, &rnv);
+
+ PERL_ARGS_ASSERT_SCAN_OCT;
+
+ *retlen = len;
+ return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv;
+}
+
+NV
+Perl_scan_hex(pTHX_ const char *start, STRLEN len, STRLEN *retlen)
+{
+ NV rnv;
+ I32 flags = *retlen ? PERL_SCAN_ALLOW_UNDERSCORES : 0;
+ const UV ruv = grok_hex (start, &len, &flags, &rnv);
+
+ PERL_ARGS_ASSERT_SCAN_HEX;
+
+ *retlen = len;
+ return (flags & PERL_SCAN_GREATER_THAN_UV_MAX) ? rnv : (NV)ruv;
}
/*
bool
Perl_grok_numeric_radix(pTHX_ const char **sp, const char *send)
{
+ PERL_ARGS_ASSERT_GROK_NUMERIC_RADIX;
+
#ifdef USE_LOCALE_NUMERIC
- if (PL_numeric_radix_sv && IN_LOCALE) {
+
+ if (IN_LC(LC_NUMERIC)) {
STRLEN len;
- char* radix = SvPV(PL_numeric_radix_sv, len);
- if (*sp + len <= send && memEQ(*sp, radix, len)) {
+ char * radix;
+ bool matches_radix = FALSE;
+ DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
+
+ STORE_LC_NUMERIC_FORCE_TO_UNDERLYING();
+
+ radix = SvPV(PL_numeric_radix_sv, len);
+ radix = savepvn(radix, len);
+
+ RESTORE_LC_NUMERIC();
+
+ if (*sp + len <= send) {
+ matches_radix = memEQ(*sp, radix, len);
+ }
+
+ Safefree(radix);
+
+ if (matches_radix) {
*sp += len;
- return TRUE;
+ return TRUE;
}
}
+
+#endif
+
/* always try "." if numeric radix didn't match because
* we may have data from different locales mixed */
-#endif
if (*sp < send && **sp == '.') {
++*sp;
return TRUE;
}
+
return FALSE;
}
/*
-=for apidoc grok_number
+=for apidoc grok_infnan
+
+Helper for C<grok_number()>, accepts various ways of spelling "infinity"
+or "not a number", and returns one of the following flag combinations:
+
+ IS_NUMBER_INFINITY
+ IS_NUMBER_NAN
+ IS_NUMBER_INFINITY | IS_NUMBER_NEG
+ IS_NUMBER_NAN | IS_NUMBER_NEG
+ 0
+
+possibly |-ed with C<IS_NUMBER_TRAILING>.
+
+If an infinity or a not-a-number is recognized, C<*sp> will point to
+one byte past the end of the recognized string. If the recognition fails,
+zero is returned, and C<*sp> will not move.
+
+=for apidoc Amn|bool|IS_NUMBER_GREATER_THAN_UV_MAX
+=for apidoc Amn|bool|IS_NUMBER_INFINITY
+=for apidoc Amn|bool|IS_NUMBER_IN_UV
+=for apidoc Amn|bool|IS_NUMBER_NAN
+=for apidoc Amn|bool|IS_NUMBER_NEG
+=for apidoc Amn|bool|IS_NUMBER_NOT_INT
+
+=cut
+*/
+
+int
+Perl_grok_infnan(pTHX_ const char** sp, const char* send)
+{
+ const char* s = *sp;
+ int flags = 0;
+#if defined(NV_INF) || defined(NV_NAN)
+ bool odh = FALSE; /* one-dot-hash: 1.#INF */
+
+ PERL_ARGS_ASSERT_GROK_INFNAN;
+
+ if (*s == '+') {
+ s++; if (s == send) return 0;
+ }
+ else if (*s == '-') {
+ flags |= IS_NUMBER_NEG; /* Yes, -NaN happens. Incorrect but happens. */
+ s++; if (s == send) return 0;
+ }
+
+ if (*s == '1') {
+ /* Visual C: 1.#SNAN, -1.#QNAN, 1#INF, 1.#IND (maybe also 1.#NAN)
+ * Let's keep the dot optional. */
+ s++; if (s == send) return 0;
+ if (*s == '.') {
+ s++; if (s == send) return 0;
+ }
+ if (*s == '#') {
+ s++; if (s == send) return 0;
+ } else
+ return 0;
+ odh = TRUE;
+ }
+
+ if (isALPHA_FOLD_EQ(*s, 'I')) {
+ /* INF or IND (1.#IND is "indeterminate", a certain type of NAN) */
+
+ s++; if (s == send || isALPHA_FOLD_NE(*s, 'N')) return 0;
+ s++; if (s == send) return 0;
+ if (isALPHA_FOLD_EQ(*s, 'F')) {
+ s++;
+ if (s < send && (isALPHA_FOLD_EQ(*s, 'I'))) {
+ int fail =
+ flags | IS_NUMBER_INFINITY | IS_NUMBER_NOT_INT | IS_NUMBER_TRAILING;
+ s++; if (s == send || isALPHA_FOLD_NE(*s, 'N')) return fail;
+ s++; if (s == send || isALPHA_FOLD_NE(*s, 'I')) return fail;
+ s++; if (s == send || isALPHA_FOLD_NE(*s, 'T')) return fail;
+ s++; if (s == send || isALPHA_FOLD_NE(*s, 'Y')) return fail;
+ s++;
+ } else if (odh) {
+ while (*s == '0') { /* 1.#INF00 */
+ s++;
+ }
+ }
+ while (s < send && isSPACE(*s))
+ s++;
+ if (s < send && *s) {
+ flags |= IS_NUMBER_TRAILING;
+ }
+ flags |= IS_NUMBER_INFINITY | IS_NUMBER_NOT_INT;
+ }
+ else if (isALPHA_FOLD_EQ(*s, 'D') && odh) { /* 1.#IND */
+ s++;
+ flags |= IS_NUMBER_NAN | IS_NUMBER_NOT_INT;
+ while (*s == '0') { /* 1.#IND00 */
+ s++;
+ }
+ if (*s) {
+ flags |= IS_NUMBER_TRAILING;
+ }
+ } else
+ return 0;
+ }
+ else {
+ /* Maybe NAN of some sort */
+
+ if (isALPHA_FOLD_EQ(*s, 'S') || isALPHA_FOLD_EQ(*s, 'Q')) {
+ /* snan, qNaN */
+ /* XXX do something with the snan/qnan difference */
+ s++; if (s == send) return 0;
+ }
+
+ if (isALPHA_FOLD_EQ(*s, 'N')) {
+ s++; if (s == send || isALPHA_FOLD_NE(*s, 'A')) return 0;
+ s++; if (s == send || isALPHA_FOLD_NE(*s, 'N')) return 0;
+ s++;
+
+ flags |= IS_NUMBER_NAN | IS_NUMBER_NOT_INT;
+
+ /* NaN can be followed by various stuff (NaNQ, NaNS), but
+ * there are also multiple different NaN values, and some
+ * implementations output the "payload" values,
+ * e.g. NaN123, NAN(abc), while some legacy implementations
+ * have weird stuff like NaN%. */
+ if (isALPHA_FOLD_EQ(*s, 'q') ||
+ isALPHA_FOLD_EQ(*s, 's')) {
+ /* "nanq" or "nans" are ok, though generating
+ * these portably is tricky. */
+ s++;
+ }
+ if (*s == '(') {
+ /* C99 style "nan(123)" or Perlish equivalent "nan($uv)". */
+ const char *t;
+ s++;
+ if (s == send) {
+ return flags | IS_NUMBER_TRAILING;
+ }
+ t = s + 1;
+ while (t < send && *t && *t != ')') {
+ t++;
+ }
+ if (t == send) {
+ return flags | IS_NUMBER_TRAILING;
+ }
+ if (*t == ')') {
+ int nantype;
+ UV nanval;
+ if (s[0] == '0' && s + 2 < t &&
+ isALPHA_FOLD_EQ(s[1], 'x') &&
+ isXDIGIT(s[2])) {
+ STRLEN len = t - s;
+ I32 flags = PERL_SCAN_ALLOW_UNDERSCORES;
+ nanval = grok_hex(s, &len, &flags, NULL);
+ if ((flags & PERL_SCAN_GREATER_THAN_UV_MAX)) {
+ nantype = 0;
+ } else {
+ nantype = IS_NUMBER_IN_UV;
+ }
+ s += len;
+ } else if (s[0] == '0' && s + 2 < t &&
+ isALPHA_FOLD_EQ(s[1], 'b') &&
+ (s[2] == '0' || s[2] == '1')) {
+ STRLEN len = t - s;
+ I32 flags = PERL_SCAN_ALLOW_UNDERSCORES;
+ nanval = grok_bin(s, &len, &flags, NULL);
+ if ((flags & PERL_SCAN_GREATER_THAN_UV_MAX)) {
+ nantype = 0;
+ } else {
+ nantype = IS_NUMBER_IN_UV;
+ }
+ s += len;
+ } else {
+ const char *u;
+ nantype =
+ grok_number_flags(s, t - s, &nanval,
+ PERL_SCAN_TRAILING |
+ PERL_SCAN_ALLOW_UNDERSCORES);
+ /* Unfortunately grok_number_flags() doesn't
+ * tell how far we got and the ')' will always
+ * be "trailing", so we need to double-check
+ * whether we had something dubious. */
+ for (u = s; u < t; u++) {
+ if (!isDIGIT(*u)) {
+ flags |= IS_NUMBER_TRAILING;
+ break;
+ }
+ }
+ s = u;
+ }
+
+ /* XXX Doesn't do octal: nan("0123").
+ * Probably not a big loss. */
+
+ if ((nantype & IS_NUMBER_NOT_INT) ||
+ !(nantype && IS_NUMBER_IN_UV)) {
+ /* XXX the nanval is currently unused, that is,
+ * not inserted as the NaN payload of the NV.
+ * But the above code already parses the C99
+ * nan(...) format. See below, and see also
+ * the nan() in POSIX.xs.
+ *
+ * Certain configuration combinations where
+ * NVSIZE is greater than UVSIZE mean that
+ * a single UV cannot contain all the possible
+ * NaN payload bits. There would need to be
+ * some more generic syntax than "nan($uv)".
+ *
+ * Issues to keep in mind:
+ *
+ * (1) In most common cases there would
+ * not be an integral number of bytes that
+ * could be set, only a certain number of bits.
+ * For example for the common case of
+ * NVSIZE == UVSIZE == 8 there is room for 52
+ * bits in the payload, but the most significant
+ * bit is commonly reserved for the
+ * signaling/quiet bit, leaving 51 bits.
+ * Furthermore, the C99 nan() is supposed
+ * to generate quiet NaNs, so it is doubtful
+ * whether it should be able to generate
+ * signaling NaNs. For the x86 80-bit doubles
+ * (if building a long double Perl) there would
+ * be 62 bits (s/q bit being the 63rd).
+ *
+ * (2) Endianness of the payload bits. If the
+ * payload is specified as an UV, the low-order
+ * bits of the UV are naturally little-endianed
+ * (rightmost) bits of the payload. The endianness
+ * of UVs and NVs can be different. */
+ return 0;
+ }
+ if (s < t) {
+ flags |= IS_NUMBER_TRAILING;
+ }
+ } else {
+ /* Looked like nan(...), but no close paren. */
+ flags |= IS_NUMBER_TRAILING;
+ }
+ } else {
+ while (s < send && isSPACE(*s))
+ s++;
+ if (s < send && *s) {
+ /* Note that we here implicitly accept (parse as
+ * "nan", but with warnings) also any other weird
+ * trailing stuff for "nan". In the above we just
+ * check that if we got the C99-style "nan(...)",
+ * the "..." looks sane.
+ * If in future we accept more ways of specifying
+ * the nan payload, the accepting would happen around
+ * here. */
+ flags |= IS_NUMBER_TRAILING;
+ }
+ }
+ s = send;
+ }
+ else
+ return 0;
+ }
+
+ while (s < send && isSPACE(*s))
+ s++;
+
+#else
+ PERL_UNUSED_ARG(send);
+#endif /* #if defined(NV_INF) || defined(NV_NAN) */
+ *sp = s;
+ return flags;
+}
+
+/*
+=for apidoc grok_number_flags
Recognise (or not) a number. The type of the number is returned
(0 if unrecognised), otherwise it is a bit-ORed combination of
-IS_NUMBER_IN_UV, IS_NUMBER_GREATER_THAN_UV_MAX, IS_NUMBER_NOT_INT,
-IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUMBER_NAN (defined in perl.h).
-
-If the value of the number can fit an in UV, it is returned in the *valuep
-IS_NUMBER_IN_UV will be set to indicate that *valuep is valid, IS_NUMBER_IN_UV
-will never be set unless *valuep is valid, but *valuep may have been assigned
-to during processing even though IS_NUMBER_IN_UV is not set on return.
-If valuep is NULL, IS_NUMBER_IN_UV will be set for the same cases as when
-valuep is non-NULL, but no actual assignment (or SEGV) will occur.
-
-IS_NUMBER_NOT_INT will be set with IS_NUMBER_IN_UV if trailing decimals were
-seen (in which case *valuep gives the true value truncated to an integer), and
-IS_NUMBER_NEG if the number is negative (in which case *valuep holds the
-absolute value). IS_NUMBER_IN_UV is not set if e notation was used or the
+C<IS_NUMBER_IN_UV>, C<IS_NUMBER_GREATER_THAN_UV_MAX>, C<IS_NUMBER_NOT_INT>,
+C<IS_NUMBER_NEG>, C<IS_NUMBER_INFINITY>, C<IS_NUMBER_NAN> (defined in perl.h).
+
+If the value of the number can fit in a UV, it is returned in C<*valuep>.
+C<IS_NUMBER_IN_UV> will be set to indicate that C<*valuep> is valid, C<IS_NUMBER_IN_UV>
+will never be set unless C<*valuep> is valid, but C<*valuep> may have been assigned
+to during processing even though C<IS_NUMBER_IN_UV> is not set on return.
+If C<valuep> is C<NULL>, C<IS_NUMBER_IN_UV> will be set for the same cases as when
+C<valuep> is non-C<NULL>, but no actual assignment (or SEGV) will occur.
+
+C<IS_NUMBER_NOT_INT> will be set with C<IS_NUMBER_IN_UV> if trailing decimals were
+seen (in which case C<*valuep> gives the true value truncated to an integer), and
+C<IS_NUMBER_NEG> if the number is negative (in which case C<*valuep> holds the
+absolute value). C<IS_NUMBER_IN_UV> is not set if e notation was used or the
number is larger than a UV.
+C<flags> allows only C<PERL_SCAN_TRAILING>, which allows for trailing
+non-numeric text on an otherwise successful I<grok>, setting
+C<IS_NUMBER_TRAILING> on the result.
+
+=for apidoc grok_number
+
+Identical to C<grok_number_flags()> with C<flags> set to zero.
+
=cut
*/
int
Perl_grok_number(pTHX_ const char *pv, STRLEN len, UV *valuep)
{
+ PERL_ARGS_ASSERT_GROK_NUMBER;
+
+ return grok_number_flags(pv, len, valuep, 0);
+}
+
+static const UV uv_max_div_10 = UV_MAX / 10;
+static const U8 uv_max_mod_10 = UV_MAX % 10;
+
+int
+Perl_grok_number_flags(pTHX_ const char *pv, STRLEN len, UV *valuep, U32 flags)
+{
const char *s = pv;
- const char *send = pv + len;
- const UV max_div_10 = UV_MAX / 10;
- const char max_mod_10 = UV_MAX % 10;
+ const char * const send = pv + len;
+ const char *d;
int numtype = 0;
- int sawinf = 0;
- int sawnan = 0;
+
+ PERL_ARGS_ASSERT_GROK_NUMBER_FLAGS;
while (s < send && isSPACE(*s))
s++;
numtype = IS_NUMBER_NEG;
}
else if (*s == '+')
- s++;
+ s++;
if (s == send)
return 0;
- /* next must be digit or the radix separator or beginning of infinity */
+ /* The first digit (after optional sign): note that might
+ * also point to "infinity" or "nan", or "1.#INF". */
+ d = s;
+
+ /* next must be digit or the radix separator or beginning of infinity/nan */
if (isDIGIT(*s)) {
/* UVs are at least 32 bits, so the first 9 decimal digits cannot
overflow. */
before checking for overflow. */
if (++s < send) {
int digit = *s - '0';
- if (digit >= 0 && digit <= 9) {
+ if (inRANGE(digit, 0, 9)) {
value = value * 10 + digit;
if (++s < send) {
digit = *s - '0';
- if (digit >= 0 && digit <= 9) {
+ if (inRANGE(digit, 0, 9)) {
value = value * 10 + digit;
if (++s < send) {
digit = *s - '0';
- if (digit >= 0 && digit <= 9) {
+ if (inRANGE(digit, 0, 9)) {
value = value * 10 + digit;
if (++s < send) {
digit = *s - '0';
- if (digit >= 0 && digit <= 9) {
+ if (inRANGE(digit, 0, 9)) {
value = value * 10 + digit;
if (++s < send) {
digit = *s - '0';
- if (digit >= 0 && digit <= 9) {
+ if (inRANGE(digit, 0, 9)) {
value = value * 10 + digit;
if (++s < send) {
digit = *s - '0';
- if (digit >= 0 && digit <= 9) {
+ if (inRANGE(digit, 0, 9)) {
value = value * 10 + digit;
if (++s < send) {
digit = *s - '0';
- if (digit >= 0 && digit <= 9) {
+ if (inRANGE(digit, 0, 9)) {
value = value * 10 + digit;
if (++s < send) {
digit = *s - '0';
- if (digit >= 0 && digit <= 9) {
+ if (inRANGE(digit, 0, 9)) {
value = value * 10 + digit;
if (++s < send) {
/* Now got 9 digits, so need to check
each time for overflow. */
digit = *s - '0';
- while (digit >= 0 && digit <= 9
- && (value < max_div_10
- || (value == max_div_10
- && digit <= max_mod_10))) {
+ while ( inRANGE(digit, 0, 9)
+ && (value < uv_max_div_10
+ || (value == uv_max_div_10
+ && digit <= uv_max_mod_10))) {
value = value * 10 + digit;
if (++s < send)
digit = *s - '0';
else
break;
}
- if (digit >= 0 && digit <= 9
+ if (inRANGE(digit, 0, 9)
&& (s < send)) {
/* value overflowed.
skip the remaining digits, don't
}
}
else
- return 0;
- } else if (*s == 'I' || *s == 'i') {
- s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
- s++; if (s == send || (*s != 'F' && *s != 'f')) return 0;
- s++; if (s < send && (*s == 'I' || *s == 'i')) {
- s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
- s++; if (s == send || (*s != 'I' && *s != 'i')) return 0;
- s++; if (s == send || (*s != 'T' && *s != 't')) return 0;
- s++; if (s == send || (*s != 'Y' && *s != 'y')) return 0;
- s++;
- }
- sawinf = 1;
- } else if (*s == 'N' || *s == 'n') {
- /* XXX TODO: There are signaling NaNs and quiet NaNs. */
- s++; if (s == send || (*s != 'A' && *s != 'a')) return 0;
- s++; if (s == send || (*s != 'N' && *s != 'n')) return 0;
- s++;
- sawnan = 1;
- } else
- return 0;
+ return 0;
+ }
- if (sawinf) {
- numtype &= IS_NUMBER_NEG; /* Keep track of sign */
- numtype |= IS_NUMBER_INFINITY | IS_NUMBER_NOT_INT;
- } else if (sawnan) {
- numtype &= IS_NUMBER_NEG; /* Keep track of sign */
- numtype |= IS_NUMBER_NAN | IS_NUMBER_NOT_INT;
- } else if (s < send) {
+ if (s > d && s < send) {
/* we can have an optional exponent part */
- if (*s == 'e' || *s == 'E') {
- /* The only flag we keep is sign. Blow away any "it's UV" */
- numtype &= IS_NUMBER_NEG;
- numtype |= IS_NUMBER_NOT_INT;
+ if (isALPHA_FOLD_EQ(*s, 'e')) {
s++;
if (s < send && (*s == '-' || *s == '+'))
s++;
s++;
} while (s < send && isDIGIT(*s));
}
+ else if (flags & PERL_SCAN_TRAILING)
+ return numtype | IS_NUMBER_TRAILING;
else
- return 0;
+ return 0;
+
+ /* The only flag we keep is sign. Blow away any "it's UV" */
+ numtype &= IS_NUMBER_NEG;
+ numtype |= IS_NUMBER_NOT_INT;
}
}
while (s < send && isSPACE(*s))
s++;
if (s >= send)
return numtype;
- if (len == 10 && memEQ(pv, "0 but true", 10)) {
+ if (memEQs(pv, len, "0 but true")) {
if (valuep)
*valuep = 0;
return IS_NUMBER_IN_UV;
}
+ /* We could be e.g. at "Inf" or "NaN", or at the "#" of "1.#INF". */
+ if ((s + 2 < send) && strchr("inqs#", toFOLD(*s))) {
+ /* Really detect inf/nan. Start at d, not s, since the above
+ * code might have already consumed the "1." or "1". */
+ const int infnan = Perl_grok_infnan(aTHX_ &d, send);
+ if ((infnan & IS_NUMBER_INFINITY)) {
+ return (numtype | infnan); /* Keep sign for infinity. */
+ }
+ else if ((infnan & IS_NUMBER_NAN)) {
+ return (numtype | infnan) & ~IS_NUMBER_NEG; /* Clear sign for nan. */
+ }
+ }
+ else if (flags & PERL_SCAN_TRAILING) {
+ return numtype | IS_NUMBER_TRAILING;
+ }
+
return 0;
}
-NV
+/*
+=for apidoc grok_atoUV
+
+parse a string, looking for a decimal unsigned integer.
+
+On entry, C<pv> points to the beginning of the string;
+C<valptr> points to a UV that will receive the converted value, if found;
+C<endptr> is either NULL or points to a variable that points to one byte
+beyond the point in C<pv> that this routine should examine.
+If C<endptr> is NULL, C<pv> is assumed to be NUL-terminated.
+
+Returns FALSE if C<pv> doesn't represent a valid unsigned integer value (with
+no leading zeros). Otherwise it returns TRUE, and sets C<*valptr> to that
+value.
+
+If you constrain the portion of C<pv> that is looked at by this function (by
+passing a non-NULL C<endptr>), and if the intial bytes of that portion form a
+valid value, it will return TRUE, setting C<*endptr> to the byte following the
+final digit of the value. But if there is no constraint at what's looked at,
+all of C<pv> must be valid in order for TRUE to be returned.
+
+The only characters this accepts are the decimal digits '0'..'9'.
+
+As opposed to L<atoi(3)> or L<strtol(3)>, C<grok_atoUV> does NOT allow optional
+leading whitespace, nor negative inputs. If such features are required, the
+calling code needs to explicitly implement those.
+
+Note that this function returns FALSE for inputs that would overflow a UV,
+or have leading zeros. Thus a single C<0> is accepted, but not C<00> nor
+C<01>, C<002>, I<etc>.
+
+Background: C<atoi> has severe problems with illegal inputs, it cannot be
+used for incremental parsing, and therefore should be avoided
+C<atoi> and C<strtol> are also affected by locale settings, which can also be
+seen as a bug (global state controlled by user environment).
+
+=cut
+
+*/
+
+bool
+Perl_grok_atoUV(const char *pv, UV *valptr, const char** endptr)
+{
+ const char* s = pv;
+ const char** eptr;
+ const char* end2; /* Used in case endptr is NULL. */
+ UV val = 0; /* The parsed value. */
+
+ PERL_ARGS_ASSERT_GROK_ATOUV;
+
+ if (endptr) {
+ eptr = endptr;
+ }
+ else {
+ end2 = s + strlen(s);
+ eptr = &end2;
+ }
+
+ if ( *eptr <= s
+ || ! isDIGIT(*s))
+ {
+ return FALSE;
+ }
+
+ /* Single-digit inputs are quite common. */
+ val = *s++ - '0';
+ if (s < *eptr && isDIGIT(*s)) {
+ /* Fail on extra leading zeros. */
+ if (val == 0)
+ return FALSE;
+ while (s < *eptr && isDIGIT(*s)) {
+ /* This could be unrolled like in grok_number(), but
+ * the expected uses of this are not speed-needy, and
+ * unlikely to need full 64-bitness. */
+ const U8 digit = *s++ - '0';
+ if (val < uv_max_div_10 ||
+ (val == uv_max_div_10 && digit <= uv_max_mod_10)) {
+ val = val * 10 + digit;
+ } else {
+ return FALSE;
+ }
+ }
+ }
+
+ if (endptr == NULL) {
+ if (*s) {
+ return FALSE; /* If endptr is NULL, no trailing non-digits allowed. */
+ }
+ }
+ else {
+ *endptr = s;
+ }
+
+ *valptr = val;
+ return TRUE;
+}
+
+#ifndef Perl_strtod
+STATIC NV
S_mulexp10(NV value, I32 exponent)
{
NV result = 1.0;
if (exponent == 0)
return value;
- else if (exponent < 0) {
- negative = 1;
- exponent = -exponent;
- }
+ if (value == 0)
+ return (NV)0;
/* On OpenVMS VAX we by default use the D_FLOAT double format,
* and that format does not have *easy* capabilities [1] for
- * overflowing doubles 'silently' as IEEE fp does. We also need
- * to support G_FLOAT on both VAX and Alpha, and though the exponent
- * range is much larger than D_FLOAT it still doesn't do silent
- * overflow. Therefore we need to detect early whether we would
- * overflow (this is the behaviour of the native string-to-float
+ * overflowing doubles 'silently' as IEEE fp does. We also need
+ * to support G_FLOAT on both VAX and Alpha, and though the exponent
+ * range is much larger than D_FLOAT it still doesn't do silent
+ * overflow. Therefore we need to detect early whether we would
+ * overflow (this is the behaviour of the native string-to-float
* conversion routines, and therefore of native applications, too).
*
* [1] Trying to establish a condition handler to trap floating point
* exceptions is not a good idea. */
-#if defined(VMS) && !defined(__IEEE_FP) && defined(NV_MAX_10_EXP)
- if (!negative &&
- (log10(value) + exponent) >= (NV_MAX_10_EXP))
- return NV_MAX;
-#endif
/* In UNICOS and in certain Cray models (such as T90) there is no
* IEEE fp, and no way at all from C to catch fp overflows gracefully.
* disable *all* floating point interrupts, a little bit too large
* a hammer. Therefore we need to catch potential overflows before
* it's too late. */
-#if defined(_UNICOS) && defined(NV_MAX_10_EXP)
- if (!negative &&
- (log10(value) + exponent) >= NV_MAX_10_EXP)
- return NV_MAX;
+
+#if ((defined(VMS) && !defined(_IEEE_FP)) || defined(_UNICOS) || defined(DOUBLE_IS_VAX_FLOAT)) && defined(NV_MAX_10_EXP)
+ STMT_START {
+ const NV exp_v = log10(value);
+ if (exponent >= NV_MAX_10_EXP || exponent + exp_v >= NV_MAX_10_EXP)
+ return NV_MAX;
+ if (exponent < 0) {
+ if (-(exponent + exp_v) >= NV_MAX_10_EXP)
+ return 0.0;
+ while (-exponent >= NV_MAX_10_EXP) {
+ /* combination does not overflow, but 10^(-exponent) does */
+ value /= 10;
+ ++exponent;
+ }
+ }
+ } STMT_END;
#endif
+ if (exponent < 0) {
+ negative = 1;
+ exponent = -exponent;
+#ifdef NV_MAX_10_EXP
+ /* for something like 1234 x 10^-309, the action of calculating
+ * the intermediate value 10^309 then returning 1234 / (10^309)
+ * will fail, since 10^309 becomes infinity. In this case try to
+ * refactor it as 123 / (10^308) etc.
+ */
+ while (value && exponent > NV_MAX_10_EXP) {
+ exponent--;
+ value /= 10;
+ }
+ if (value == 0.0)
+ return value;
+#endif
+ }
+#if defined(__osf__)
+ /* Even with cc -ieee + ieee_set_fp_control(IEEE_TRAP_ENABLE_INV)
+ * Tru64 fp behavior on inf/nan is somewhat broken. Another way
+ * to do this would be ieee_set_fp_control(IEEE_TRAP_ENABLE_OVF)
+ * but that breaks another set of infnan.t tests. */
+# define FP_OVERFLOWS_TO_ZERO
+#endif
for (bit = 1; exponent; bit <<= 1) {
if (exponent & bit) {
exponent ^= bit;
result *= power;
+#ifdef FP_OVERFLOWS_TO_ZERO
+ if (result == 0)
+# ifdef NV_INF
+ return value < 0 ? -NV_INF : NV_INF;
+# else
+ return value < 0 ? -FLT_MAX : FLT_MAX;
+# endif
+#endif
+ /* Floating point exceptions are supposed to be turned off,
+ * but if we're obviously done, don't risk another iteration.
+ */
+ if (exponent == 0) break;
}
- /* Floating point exceptions are supposed to be turned off. */
power *= power;
}
return negative ? value / result : value * result;
}
+#endif /* #ifndef Perl_strtod */
+
+#ifdef Perl_strtod
+# define ATOF(s, x) my_atof2(s, &x)
+#else
+# define ATOF(s, x) Perl_atof2(s, x)
+#endif
NV
Perl_my_atof(pTHX_ const char* s)
{
+ /* 's' must be NUL terminated */
+
NV x = 0.0;
-#ifdef USE_LOCALE_NUMERIC
- if (PL_numeric_local && IN_LOCALE) {
- NV y;
-
- /* Scan the number twice; once using locale and once without;
- * choose the larger result (in absolute value). */
- Perl_atof2(aTHX_ s, &x);
- SET_NUMERIC_STANDARD();
- Perl_atof2(aTHX_ s, &y);
- SET_NUMERIC_LOCAL();
- if ((y < 0.0 && y < x) || (y > 0.0 && y > x))
- return y;
- }
- else
- Perl_atof2(aTHX_ s, &x);
+
+ PERL_ARGS_ASSERT_MY_ATOF;
+
+#if ! defined(USE_LOCALE_NUMERIC)
+
+ ATOF(s, x);
+
#else
- Perl_atof2(aTHX_ s, &x);
+
+ {
+ DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
+ STORE_LC_NUMERIC_SET_TO_NEEDED();
+ if (! (PL_numeric_radix_sv && IN_LC(LC_NUMERIC))) {
+ ATOF(s,x);
+ }
+ else {
+
+ /* Look through the string for the first thing that looks like a
+ * decimal point: either the value in the current locale or the
+ * standard fallback of '.'. The one which appears earliest in the
+ * input string is the one that we should have atof look for. Note
+ * that we have to determine this beforehand because on some
+ * systems, Perl_atof2 is just a wrapper around the system's atof.
+ * */
+ const char * const standard_pos = strchr(s, '.');
+ const char * const local_pos
+ = strstr(s, SvPV_nolen(PL_numeric_radix_sv));
+ const bool use_standard_radix
+ = standard_pos && (!local_pos || standard_pos < local_pos);
+
+ if (use_standard_radix) {
+ SET_NUMERIC_STANDARD();
+ LOCK_LC_NUMERIC_STANDARD();
+ }
+
+ ATOF(s,x);
+
+ if (use_standard_radix) {
+ UNLOCK_LC_NUMERIC_STANDARD();
+ SET_NUMERIC_UNDERLYING();
+ }
+ }
+ RESTORE_LC_NUMERIC();
+ }
+
#endif
+
return x;
}
+#if defined(NV_INF) || defined(NV_NAN)
+
+#ifdef USING_MSVC6
+# pragma warning(push)
+# pragma warning(disable:4756;disable:4056)
+#endif
+static char*
+S_my_atof_infnan(pTHX_ const char* s, bool negative, const char* send, NV* value)
+{
+ const char *p0 = negative ? s - 1 : s;
+ const char *p = p0;
+ const int infnan = grok_infnan(&p, send);
+ if (infnan && p != p0) {
+ /* If we can generate inf/nan directly, let's do so. */
+#ifdef NV_INF
+ if ((infnan & IS_NUMBER_INFINITY)) {
+ *value = (infnan & IS_NUMBER_NEG) ? -NV_INF: NV_INF;
+ return (char*)p;
+ }
+#endif
+#ifdef NV_NAN
+ if ((infnan & IS_NUMBER_NAN)) {
+ *value = NV_NAN;
+ return (char*)p;
+ }
+#endif
+#ifdef Perl_strtod
+ /* If still here, we didn't have either NV_INF or NV_NAN,
+ * and can try falling back to native strtod/strtold.
+ *
+ * The native interface might not recognize all the possible
+ * inf/nan strings Perl recognizes. What we can try
+ * is to try faking the input. We will try inf/-inf/nan
+ * as the most promising/portable input. */
+ {
+ const char* fake = "silence compiler warning";
+ char* endp;
+ NV nv;
+#ifdef NV_INF
+ if ((infnan & IS_NUMBER_INFINITY)) {
+ fake = ((infnan & IS_NUMBER_NEG)) ? "-inf" : "inf";
+ }
+#endif
+#ifdef NV_NAN
+ if ((infnan & IS_NUMBER_NAN)) {
+ fake = "nan";
+ }
+#endif
+ assert(strNE(fake, "silence compiler warning"));
+ nv = S_strtod(aTHX_ fake, &endp);
+ if (fake != endp) {
+#ifdef NV_INF
+ if ((infnan & IS_NUMBER_INFINITY)) {
+# ifdef Perl_isinf
+ if (Perl_isinf(nv))
+ *value = nv;
+# else
+ /* last resort, may generate SIGFPE */
+ *value = Perl_exp((NV)1e9);
+ if ((infnan & IS_NUMBER_NEG))
+ *value = -*value;
+# endif
+ return (char*)p; /* p, not endp */
+ }
+#endif
+#ifdef NV_NAN
+ if ((infnan & IS_NUMBER_NAN)) {
+# ifdef Perl_isnan
+ if (Perl_isnan(nv))
+ *value = nv;
+# else
+ /* last resort, may generate SIGFPE */
+ *value = Perl_log((NV)-1.0);
+# endif
+ return (char*)p; /* p, not endp */
+#endif
+ }
+ }
+ }
+#endif /* #ifdef Perl_strtod */
+ }
+ return NULL;
+}
+#ifdef USING_MSVC6
+# pragma warning(pop)
+#endif
+
+#endif /* if defined(NV_INF) || defined(NV_NAN) */
+
char*
Perl_my_atof2(pTHX_ const char* orig, NV* value)
{
- NV result = 0.0;
+ PERL_ARGS_ASSERT_MY_ATOF2;
+ return my_atof3(orig, value, 0);
+}
+
+char*
+Perl_my_atof3(pTHX_ const char* orig, NV* value, const STRLEN len)
+{
+ const char* s = orig;
+ NV result[3] = {0.0, 0.0, 0.0};
+#if defined(USE_PERL_ATOF) || defined(Perl_strtod)
+ const char* send = s + ((len != 0)
+ ? len
+ : strlen(orig)); /* one past the last */
bool negative = 0;
- char* s = (char*)orig;
- char* send = s + strlen(orig) - 1;
- bool seendigit = 0;
- I32 expextra = 0;
+#endif
+#if defined(USE_PERL_ATOF) && !defined(Perl_strtod)
+ UV accumulator[2] = {0,0}; /* before/after dp */
+ bool seen_digit = 0;
+ I32 exp_adjust[2] = {0,0};
+ I32 exp_acc[2] = {-1, -1};
+ /* the current exponent adjust for the accumulators */
I32 exponent = 0;
- I32 i;
-/* this is arbitrary */
-#define PARTLIM 6
-/* we want the largest integers we can usefully use */
-#if defined(HAS_QUAD) && defined(USE_64_BIT_INT)
-# define PARTSIZE ((int)TYPE_DIGITS(U64)-1)
- U64 part[PARTLIM];
-#else
-# define PARTSIZE ((int)TYPE_DIGITS(U32)-1)
- U32 part[PARTLIM];
+ I32 seen_dp = 0;
+ I32 digit = 0;
+ I32 old_digit = 0;
+ I32 sig_digits = 0; /* noof significant digits seen so far */
#endif
- I32 ipart = 0; /* index into part[] */
- I32 offcount; /* number of digits in least significant part */
+
+#if defined(USE_PERL_ATOF) || defined(Perl_strtod)
+ PERL_ARGS_ASSERT_MY_ATOF3;
/* leading whitespace */
- while (isSPACE(*s))
+ while (s < send && isSPACE(*s))
++s;
/* sign */
switch (*s) {
case '-':
negative = 1;
- /* fall through */
+ /* FALLTHROUGH */
case '+':
++s;
}
+#endif
- part[0] = offcount = 0;
- if (isDIGIT(*s)) {
- seendigit = 1; /* get this over with */
+#ifdef Perl_strtod
+ {
+ char* endp;
+ char* copy = NULL;
- /* skip leading zeros */
- while (*s == '0')
- ++s;
+ if ((endp = S_my_atof_infnan(aTHX_ s, negative, send, value)))
+ return endp;
+
+ /* strtold() accepts 0x-prefixed hex and in POSIX implementations,
+ 0b-prefixed binary numbers, which is backward incompatible
+ */
+ if ((len == 0 || len >= 2) && *s == '0' &&
+ (isALPHA_FOLD_EQ(s[1], 'x') || isALPHA_FOLD_EQ(s[1], 'b'))) {
+ *value = 0;
+ return (char *)s+1;
+ }
+
+ /* If the length is passed in, the input string isn't NUL-terminated,
+ * and in it turns out the function below assumes it is; therefore we
+ * create a copy and NUL-terminate that */
+ if (len) {
+ Newx(copy, len + 1, char);
+ Copy(orig, copy, len, char);
+ copy[len] = '\0';
+ s = copy + (s - orig);
+ }
+
+ result[2] = S_strtod(aTHX_ s, &endp);
+
+ /* If we created a copy, 'endp' is in terms of that. Convert back to
+ * the original */
+ if (copy) {
+ s = (s - copy) + (char *) orig;
+ endp = (endp - copy) + (char *) orig;
+ Safefree(copy);
+ }
+
+ if (s != endp) {
+ *value = negative ? -result[2] : result[2];
+ return endp;
+ }
+ return NULL;
}
+#elif defined(USE_PERL_ATOF)
- /* integer digits */
- while (isDIGIT(*s)) {
- if (++offcount > PARTSIZE) {
- if (++ipart < PARTLIM) {
- part[ipart] = 0;
- offcount = 1; /* ++0 */
- }
- else {
+/* There is no point in processing more significant digits
+ * than the NV can hold. Note that NV_DIG is a lower-bound value,
+ * while we need an upper-bound value. We add 2 to account for this;
+ * since it will have been conservative on both the first and last digit.
+ * For example a 32-bit mantissa with an exponent of 4 would have
+ * exact values in the set
+ * 4
+ * 8
+ * ..
+ * 17179869172
+ * 17179869176
+ * 17179869180
+ *
+ * where for the purposes of calculating NV_DIG we would have to discount
+ * both the first and last digit, since neither can hold all values from
+ * 0..9; but for calculating the value we must examine those two digits.
+ */
+#ifdef MAX_SIG_DIG_PLUS
+ /* It is not necessarily the case that adding 2 to NV_DIG gets all the
+ possible digits in a NV, especially if NVs are not IEEE compliant
+ (e.g., long doubles on IRIX) - Allen <allens@cpan.org> */
+# define MAX_SIG_DIGITS (NV_DIG+MAX_SIG_DIG_PLUS)
+#else
+# define MAX_SIG_DIGITS (NV_DIG+2)
+#endif
+
+/* the max number we can accumulate in a UV, and still safely do 10*N+9 */
+#define MAX_ACCUMULATE ( (UV) ((UV_MAX - 9)/10))
+
+#if defined(NV_INF) || defined(NV_NAN)
+ {
+ char* endp;
+ if ((endp = S_my_atof_infnan(aTHX_ s, negative, send, value)))
+ return endp;
+ }
+#endif
+
+ /* we accumulate digits into an integer; when this becomes too
+ * large, we add the total to NV and start again */
+
+ while (s < send) {
+ if (isDIGIT(*s)) {
+ seen_digit = 1;
+ old_digit = digit;
+ digit = *s++ - '0';
+ if (seen_dp)
+ exp_adjust[1]++;
+
+ /* don't start counting until we see the first significant
+ * digit, eg the 5 in 0.00005... */
+ if (!sig_digits && digit == 0)
+ continue;
+
+ if (++sig_digits > MAX_SIG_DIGITS) {
/* limits of precision reached */
- --ipart;
- --offcount;
- if (*s >= '5')
- ++part[ipart];
- while (isDIGIT(*s)) {
- ++expextra;
+ if (digit > 5) {
+ ++accumulator[seen_dp];
+ } else if (digit == 5) {
+ if (old_digit % 2) { /* round to even - Allen */
+ ++accumulator[seen_dp];
+ }
+ }
+ if (seen_dp) {
+ exp_adjust[1]--;
+ } else {
+ exp_adjust[0]++;
+ }
+ /* skip remaining digits */
+ while (s < send && isDIGIT(*s)) {
++s;
+ if (! seen_dp) {
+ exp_adjust[0]++;
+ }
}
/* warn of loss of precision? */
- break;
}
- }
- part[ipart] = part[ipart] * 10 + (*s++ - '0');
- }
-
- /* decimal point */
- if (GROK_NUMERIC_RADIX((const char **)&s, send)) {
- if (isDIGIT(*s))
- seendigit = 1; /* get this over with */
-
- /* decimal digits */
- while (isDIGIT(*s)) {
- if (++offcount > PARTSIZE) {
- if (++ipart < PARTLIM) {
- part[ipart] = 0;
- offcount = 1; /* ++0 */
+ else {
+ if (accumulator[seen_dp] > MAX_ACCUMULATE) {
+ /* add accumulator to result and start again */
+ result[seen_dp] = S_mulexp10(result[seen_dp],
+ exp_acc[seen_dp])
+ + (NV)accumulator[seen_dp];
+ accumulator[seen_dp] = 0;
+ exp_acc[seen_dp] = 0;
}
- else {
- /* limits of precision reached */
- --ipart;
- --offcount;
- if (*s >= '5')
- ++part[ipart];
- while (isDIGIT(*s))
- ++s;
- /* warn of loss of precision? */
- break;
+ accumulator[seen_dp] = accumulator[seen_dp] * 10 + digit;
+ ++exp_acc[seen_dp];
+ }
+ }
+ else if (!seen_dp && GROK_NUMERIC_RADIX(&s, send)) {
+ seen_dp = 1;
+ if (sig_digits > MAX_SIG_DIGITS) {
+ while (s < send && isDIGIT(*s)) {
+ ++s;
}
+ break;
}
- --expextra;
- part[ipart] = part[ipart] * 10 + (*s++ - '0');
+ }
+ else {
+ break;
}
}
- /* combine components of mantissa */
- for (i = 0; i <= ipart; ++i)
- result += S_mulexp10((NV)part[ipart - i],
- i ? offcount + (i - 1) * PARTSIZE : 0);
+ result[0] = S_mulexp10(result[0], exp_acc[0]) + (NV)accumulator[0];
+ if (seen_dp) {
+ result[1] = S_mulexp10(result[1], exp_acc[1]) + (NV)accumulator[1];
+ }
- if (seendigit && (*s == 'e' || *s == 'E')) {
+ if (s < send && seen_digit && (isALPHA_FOLD_EQ(*s, 'e'))) {
bool expnegative = 0;
++s;
switch (*s) {
case '-':
expnegative = 1;
- /* fall through */
+ /* FALLTHROUGH */
case '+':
++s;
}
- while (isDIGIT(*s))
+ while (s < send && isDIGIT(*s))
exponent = exponent * 10 + (*s++ - '0');
if (expnegative)
exponent = -exponent;
}
/* now apply the exponent */
- exponent += expextra;
- result = S_mulexp10(result, exponent);
+
+ if (seen_dp) {
+ result[2] = S_mulexp10(result[0],exponent+exp_adjust[0])
+ + S_mulexp10(result[1],exponent-exp_adjust[1]);
+ } else {
+ result[2] = S_mulexp10(result[0],exponent+exp_adjust[0]);
+ }
/* now apply the sign */
if (negative)
- result = -result;
- *value = result;
- return s;
+ result[2] = -result[2];
+#endif /* USE_PERL_ATOF */
+ *value = result[2];
+ return (char *)s;
}
+/*
+=for apidoc isinfnan
+
+C<Perl_isinfnan()> is utility function that returns true if the NV
+argument is either an infinity or a C<NaN>, false otherwise. To test
+in more detail, use C<Perl_isinf()> and C<Perl_isnan()>.
+
+This is also the logical inverse of Perl_isfinite().
+
+=cut
+*/
+bool
+Perl_isinfnan(NV nv)
+{
+ PERL_UNUSED_ARG(nv);
+#ifdef Perl_isinf
+ if (Perl_isinf(nv))
+ return TRUE;
+#endif
+#ifdef Perl_isnan
+ if (Perl_isnan(nv))
+ return TRUE;
+#endif
+ return FALSE;
+}
+
+/*
+=for apidoc
+
+Checks whether the argument would be either an infinity or C<NaN> when used
+as a number, but is careful not to trigger non-numeric or uninitialized
+warnings. it assumes the caller has done C<SvGETMAGIC(sv)> already.
+
+=cut
+*/
+
+bool
+Perl_isinfnansv(pTHX_ SV *sv)
+{
+ PERL_ARGS_ASSERT_ISINFNANSV;
+ if (!SvOK(sv))
+ return FALSE;
+ if (SvNOKp(sv))
+ return Perl_isinfnan(SvNVX(sv));
+ if (SvIOKp(sv))
+ return FALSE;
+ {
+ STRLEN len;
+ const char *s = SvPV_nomg_const(sv, len);
+ return cBOOL(grok_infnan(&s, s+len));
+ }
+}
+
+#ifndef HAS_MODFL
+/* C99 has truncl, pre-C99 Solaris had aintl. We can use either with
+ * copysignl to emulate modfl, which is in some platforms missing or
+ * broken. */
+# if defined(HAS_TRUNCL) && defined(HAS_COPYSIGNL)
+long double
+Perl_my_modfl(long double x, long double *ip)
+{
+ *ip = truncl(x);
+ return (x == *ip ? copysignl(0.0L, x) : x - *ip);
+}
+# elif defined(HAS_AINTL) && defined(HAS_COPYSIGNL)
+long double
+Perl_my_modfl(long double x, long double *ip)
+{
+ *ip = aintl(x);
+ return (x == *ip ? copysignl(0.0L, x) : x - *ip);
+}
+# endif
+#endif
+
+/* Similarly, with ilogbl and scalbnl we can emulate frexpl. */
+#if ! defined(HAS_FREXPL) && defined(HAS_ILOGBL) && defined(HAS_SCALBNL)
+long double
+Perl_my_frexpl(long double x, int *e) {
+ *e = x == 0.0L ? 0 : ilogbl(x) + 1;
+ return (scalbnl(x, -*e));
+}
+#endif
+
+/*
+=for apidoc Perl_signbit
+
+Return a non-zero integer if the sign bit on an NV is set, and 0 if
+it is not.
+
+If F<Configure> detects this system has a C<signbit()> that will work with
+our NVs, then we just use it via the C<#define> in F<perl.h>. Otherwise,
+fall back on this implementation. The main use of this function
+is catching C<-0.0>.
+
+C<Configure> notes: This function is called C<'Perl_signbit'> instead of a
+plain C<'signbit'> because it is easy to imagine a system having a C<signbit()>
+function or macro that doesn't happen to work with our particular choice
+of NVs. We shouldn't just re-C<#define> C<signbit> as C<Perl_signbit> and expect
+the standard system headers to be happy. Also, this is a no-context
+function (no C<pTHX_>) because C<Perl_signbit()> is usually re-C<#defined> in
+F<perl.h> as a simple macro call to the system's C<signbit()>.
+Users should just always call C<Perl_signbit()>.
+
+=cut
+*/
+#if !defined(HAS_SIGNBIT)
+int
+Perl_signbit(NV x) {
+# ifdef Perl_fp_class_nzero
+ return Perl_fp_class_nzero(x);
+ /* Try finding the high byte, and assume it's highest bit
+ * is the sign. This assumption is probably wrong somewhere. */
+# elif defined(USE_LONG_DOUBLE) && LONG_DOUBLEKIND == LONG_DOUBLE_IS_X86_80_BIT_LITTLE_ENDIAN
+ return (((unsigned char *)&x)[9] & 0x80);
+# elif defined(NV_LITTLE_ENDIAN)
+ /* Note that NVSIZE is sizeof(NV), which would make the below be
+ * wrong if the end bytes are unused, which happens with the x86
+ * 80-bit long doubles, which is why take care of that above. */
+ return (((unsigned char *)&x)[NVSIZE - 1] & 0x80);
+# elif defined(NV_BIG_ENDIAN)
+ return (((unsigned char *)&x)[0] & 0x80);
+# else
+ /* This last resort fallback is wrong for the negative zero. */
+ return (x < 0.0) ? 1 : 0;
+# endif
+}
+#endif
+
+/*
+ * ex: set ts=8 sts=4 sw=4 et:
+ */