/
printf_fp.c
1333 lines (1196 loc) · 35.9 KB
/
printf_fp.c
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/* Floating point output for `printf'.
Copyright (C) 1995-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* The gmp headers need some configuration frobs. */
#define HAVE_ALLOCA 1
#include <libioP.h>
#include <alloca.h>
#include <ctype.h>
#include <float.h>
#include <gmp-mparam.h>
#include <gmp.h>
#include <ieee754.h>
#include <stdlib/gmp-impl.h>
#include <stdlib/longlong.h>
#include <stdlib/fpioconst.h>
#include <locale/localeinfo.h>
#include <limits.h>
#include <math.h>
#include <printf.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <wchar.h>
#include <stdbool.h>
#include <rounding-mode.h>
#ifdef COMPILE_WPRINTF
# define CHAR_T wchar_t
#else
# define CHAR_T char
#endif
#include "_i18n_number.h"
#ifndef NDEBUG
# define NDEBUG /* Undefine this for debugging assertions. */
#endif
#include <assert.h>
/* This defines make it possible to use the same code for GNU C library and
the GNU I/O library. */
#define PUT(f, s, n) _IO_sputn (f, s, n)
#define PAD(f, c, n) (wide ? _IO_wpadn (f, c, n) : _IO_padn (f, c, n))
/* We use this file GNU C library and GNU I/O library. So make
names equal. */
#undef putc
#define putc(c, f) (wide \
? (int)_IO_putwc_unlocked (c, f) : _IO_putc_unlocked (c, f))
#define size_t _IO_size_t
#define FILE _IO_FILE
/* Macros for doing the actual output. */
#define outchar(ch) \
do \
{ \
register const int outc = (ch); \
if (putc (outc, fp) == EOF) \
{ \
if (buffer_malloced) \
free (wbuffer); \
return -1; \
} \
++done; \
} while (0)
#define PRINT(ptr, wptr, len) \
do \
{ \
register size_t outlen = (len); \
if (len > 20) \
{ \
if (PUT (fp, wide ? (const char *) wptr : ptr, outlen) != outlen) \
{ \
if (buffer_malloced) \
free (wbuffer); \
return -1; \
} \
ptr += outlen; \
done += outlen; \
} \
else \
{ \
if (wide) \
while (outlen-- > 0) \
outchar (*wptr++); \
else \
while (outlen-- > 0) \
outchar (*ptr++); \
} \
} while (0)
#define PADN(ch, len) \
do \
{ \
if (PAD (fp, ch, len) != len) \
{ \
if (buffer_malloced) \
free (wbuffer); \
return -1; \
} \
done += len; \
} \
while (0)
/* We use the GNU MP library to handle large numbers.
An MP variable occupies a varying number of entries in its array. We keep
track of this number for efficiency reasons. Otherwise we would always
have to process the whole array. */
#define MPN_VAR(name) mp_limb_t *name; mp_size_t name##size
#define MPN_ASSIGN(dst,src) \
memcpy (dst, src, (dst##size = src##size) * sizeof (mp_limb_t))
#define MPN_GE(u,v) \
(u##size > v##size || (u##size == v##size && __mpn_cmp (u, v, u##size) >= 0))
extern int __isinfl_internal (long double) attribute_hidden;
extern int __isnanl_internal (long double) attribute_hidden;
extern mp_size_t __mpn_extract_double (mp_ptr res_ptr, mp_size_t size,
int *expt, int *is_neg,
double value);
extern mp_size_t __mpn_extract_long_double (mp_ptr res_ptr, mp_size_t size,
int *expt, int *is_neg,
long double value);
extern unsigned int __guess_grouping (unsigned int intdig_max,
const char *grouping);
static wchar_t *group_number (wchar_t *buf, wchar_t *bufend,
unsigned int intdig_no, const char *grouping,
wchar_t thousands_sep, int ngroups)
internal_function;
int
___printf_fp (FILE *fp,
const struct printf_info *info,
const void *const *args)
{
/* The floating-point value to output. */
union
{
double dbl;
__long_double_t ldbl;
}
fpnum;
/* Locale-dependent representation of decimal point. */
const char *decimal;
wchar_t decimalwc;
/* Locale-dependent thousands separator and grouping specification. */
const char *thousands_sep = NULL;
wchar_t thousands_sepwc = 0;
const char *grouping;
/* "NaN" or "Inf" for the special cases. */
const char *special = NULL;
const wchar_t *wspecial = NULL;
/* We need just a few limbs for the input before shifting to the right
position. */
mp_limb_t fp_input[(LDBL_MANT_DIG + BITS_PER_MP_LIMB - 1) / BITS_PER_MP_LIMB];
/* We need to shift the contents of fp_input by this amount of bits. */
int to_shift = 0;
/* The fraction of the floting-point value in question */
MPN_VAR(frac);
/* and the exponent. */
int exponent;
/* Sign of the exponent. */
int expsign = 0;
/* Sign of float number. */
int is_neg = 0;
/* Scaling factor. */
MPN_VAR(scale);
/* Temporary bignum value. */
MPN_VAR(tmp);
/* The type of output format that will be used: 'e'/'E' or 'f'. */
int type;
/* Counter for number of written characters. */
int done = 0;
/* General helper (carry limb). */
mp_limb_t cy;
/* Nonzero if this is output on a wide character stream. */
int wide = info->wide;
/* Buffer in which we produce the output. */
wchar_t *wbuffer = NULL;
/* Flag whether wbuffer is malloc'ed or not. */
int buffer_malloced = 0;
auto wchar_t hack_digit (void);
wchar_t hack_digit (void)
{
mp_limb_t hi;
if (expsign != 0 && type == 'f' && exponent-- > 0)
hi = 0;
else if (scalesize == 0)
{
hi = frac[fracsize - 1];
frac[fracsize - 1] = __mpn_mul_1 (frac, frac, fracsize - 1, 10);
}
else
{
if (fracsize < scalesize)
hi = 0;
else
{
hi = mpn_divmod (tmp, frac, fracsize, scale, scalesize);
tmp[fracsize - scalesize] = hi;
hi = tmp[0];
fracsize = scalesize;
while (fracsize != 0 && frac[fracsize - 1] == 0)
--fracsize;
if (fracsize == 0)
{
/* We're not prepared for an mpn variable with zero
limbs. */
fracsize = 1;
return L'0' + hi;
}
}
mp_limb_t _cy = __mpn_mul_1 (frac, frac, fracsize, 10);
if (_cy != 0)
frac[fracsize++] = _cy;
}
return L'0' + hi;
}
/* Figure out the decimal point character. */
if (info->extra == 0)
{
decimal = _NL_CURRENT (LC_NUMERIC, DECIMAL_POINT);
decimalwc = _NL_CURRENT_WORD (LC_NUMERIC, _NL_NUMERIC_DECIMAL_POINT_WC);
}
else
{
decimal = _NL_CURRENT (LC_MONETARY, MON_DECIMAL_POINT);
if (*decimal == '\0')
decimal = _NL_CURRENT (LC_NUMERIC, DECIMAL_POINT);
decimalwc = _NL_CURRENT_WORD (LC_MONETARY,
_NL_MONETARY_DECIMAL_POINT_WC);
if (decimalwc == L'\0')
decimalwc = _NL_CURRENT_WORD (LC_NUMERIC,
_NL_NUMERIC_DECIMAL_POINT_WC);
}
/* The decimal point character must not be zero. */
assert (*decimal != '\0');
assert (decimalwc != L'\0');
if (info->group)
{
if (info->extra == 0)
grouping = _NL_CURRENT (LC_NUMERIC, GROUPING);
else
grouping = _NL_CURRENT (LC_MONETARY, MON_GROUPING);
if (*grouping <= 0 || *grouping == CHAR_MAX)
grouping = NULL;
else
{
/* Figure out the thousands separator character. */
if (wide)
{
if (info->extra == 0)
thousands_sepwc =
_NL_CURRENT_WORD (LC_NUMERIC, _NL_NUMERIC_THOUSANDS_SEP_WC);
else
thousands_sepwc =
_NL_CURRENT_WORD (LC_MONETARY,
_NL_MONETARY_THOUSANDS_SEP_WC);
}
else
{
if (info->extra == 0)
thousands_sep = _NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP);
else
thousands_sep = _NL_CURRENT (LC_MONETARY, MON_THOUSANDS_SEP);
}
if ((wide && thousands_sepwc == L'\0')
|| (! wide && *thousands_sep == '\0'))
grouping = NULL;
else if (thousands_sepwc == L'\0')
/* If we are printing multibyte characters and there is a
multibyte representation for the thousands separator,
we must ensure the wide character thousands separator
is available, even if it is fake. */
thousands_sepwc = 0xfffffffe;
}
}
else
grouping = NULL;
/* Fetch the argument value. */
#ifndef __NO_LONG_DOUBLE_MATH
if (info->is_long_double && sizeof (long double) > sizeof (double))
{
fpnum.ldbl = *(const long double *) args[0];
/* Check for special values: not a number or infinity. */
int res;
if (__isnanl (fpnum.ldbl))
{
union ieee854_long_double u = { .d = fpnum.ldbl };
is_neg = u.ieee.negative != 0;
if (isupper (info->spec))
{
special = "NAN";
wspecial = L"NAN";
}
else
{
special = "nan";
wspecial = L"nan";
}
}
else if ((res = __isinfl (fpnum.ldbl)))
{
is_neg = res < 0;
if (isupper (info->spec))
{
special = "INF";
wspecial = L"INF";
}
else
{
special = "inf";
wspecial = L"inf";
}
}
else
{
fracsize = __mpn_extract_long_double (fp_input,
(sizeof (fp_input) /
sizeof (fp_input[0])),
&exponent, &is_neg,
fpnum.ldbl);
to_shift = 1 + fracsize * BITS_PER_MP_LIMB - LDBL_MANT_DIG;
}
}
else
#endif /* no long double */
{
fpnum.dbl = *(const double *) args[0];
/* Check for special values: not a number or infinity. */
int res;
if (__isnan (fpnum.dbl))
{
union ieee754_double u = { .d = fpnum.dbl };
is_neg = u.ieee.negative != 0;
if (isupper (info->spec))
{
special = "NAN";
wspecial = L"NAN";
}
else
{
special = "nan";
wspecial = L"nan";
}
}
else if ((res = __isinf (fpnum.dbl)))
{
is_neg = res < 0;
if (isupper (info->spec))
{
special = "INF";
wspecial = L"INF";
}
else
{
special = "inf";
wspecial = L"inf";
}
}
else
{
fracsize = __mpn_extract_double (fp_input,
(sizeof (fp_input)
/ sizeof (fp_input[0])),
&exponent, &is_neg, fpnum.dbl);
to_shift = 1 + fracsize * BITS_PER_MP_LIMB - DBL_MANT_DIG;
}
}
if (special)
{
int width = info->width;
if (is_neg || info->showsign || info->space)
--width;
width -= 3;
if (!info->left && width > 0)
PADN (' ', width);
if (is_neg)
outchar ('-');
else if (info->showsign)
outchar ('+');
else if (info->space)
outchar (' ');
PRINT (special, wspecial, 3);
if (info->left && width > 0)
PADN (' ', width);
return done;
}
/* We need three multiprecision variables. Now that we have the exponent
of the number we can allocate the needed memory. It would be more
efficient to use variables of the fixed maximum size but because this
would be really big it could lead to memory problems. */
{
mp_size_t bignum_size = ((ABS (exponent) + BITS_PER_MP_LIMB - 1)
/ BITS_PER_MP_LIMB
+ (LDBL_MANT_DIG / BITS_PER_MP_LIMB > 2 ? 8 : 4))
* sizeof (mp_limb_t);
frac = (mp_limb_t *) alloca (bignum_size);
tmp = (mp_limb_t *) alloca (bignum_size);
scale = (mp_limb_t *) alloca (bignum_size);
}
/* We now have to distinguish between numbers with positive and negative
exponents because the method used for the one is not applicable/efficient
for the other. */
scalesize = 0;
if (exponent > 2)
{
/* |FP| >= 8.0. */
int scaleexpo = 0;
int explog = LDBL_MAX_10_EXP_LOG;
int exp10 = 0;
const struct mp_power *powers = &_fpioconst_pow10[explog + 1];
int cnt_h, cnt_l, i;
if ((exponent + to_shift) % BITS_PER_MP_LIMB == 0)
{
MPN_COPY_DECR (frac + (exponent + to_shift) / BITS_PER_MP_LIMB,
fp_input, fracsize);
fracsize += (exponent + to_shift) / BITS_PER_MP_LIMB;
}
else
{
cy = __mpn_lshift (frac + (exponent + to_shift) / BITS_PER_MP_LIMB,
fp_input, fracsize,
(exponent + to_shift) % BITS_PER_MP_LIMB);
fracsize += (exponent + to_shift) / BITS_PER_MP_LIMB;
if (cy)
frac[fracsize++] = cy;
}
MPN_ZERO (frac, (exponent + to_shift) / BITS_PER_MP_LIMB);
assert (powers > &_fpioconst_pow10[0]);
do
{
--powers;
/* The number of the product of two binary numbers with n and m
bits respectively has m+n or m+n-1 bits. */
if (exponent >= scaleexpo + powers->p_expo - 1)
{
if (scalesize == 0)
{
#ifndef __NO_LONG_DOUBLE_MATH
if (LDBL_MANT_DIG > _FPIO_CONST_OFFSET * BITS_PER_MP_LIMB
&& info->is_long_double)
{
#define _FPIO_CONST_SHIFT \
(((LDBL_MANT_DIG + BITS_PER_MP_LIMB - 1) / BITS_PER_MP_LIMB) \
- _FPIO_CONST_OFFSET)
/* 64bit const offset is not enough for
IEEE quad long double. */
tmpsize = powers->arraysize + _FPIO_CONST_SHIFT;
memcpy (tmp + _FPIO_CONST_SHIFT,
&__tens[powers->arrayoff],
tmpsize * sizeof (mp_limb_t));
MPN_ZERO (tmp, _FPIO_CONST_SHIFT);
/* Adjust exponent, as scaleexpo will be this much
bigger too. */
exponent += _FPIO_CONST_SHIFT * BITS_PER_MP_LIMB;
}
else
#endif
{
tmpsize = powers->arraysize;
memcpy (tmp, &__tens[powers->arrayoff],
tmpsize * sizeof (mp_limb_t));
}
}
else
{
cy = __mpn_mul (tmp, scale, scalesize,
&__tens[powers->arrayoff
+ _FPIO_CONST_OFFSET],
powers->arraysize - _FPIO_CONST_OFFSET);
tmpsize = scalesize + powers->arraysize - _FPIO_CONST_OFFSET;
if (cy == 0)
--tmpsize;
}
if (MPN_GE (frac, tmp))
{
int cnt;
MPN_ASSIGN (scale, tmp);
count_leading_zeros (cnt, scale[scalesize - 1]);
scaleexpo = (scalesize - 2) * BITS_PER_MP_LIMB - cnt - 1;
exp10 |= 1 << explog;
}
}
--explog;
}
while (powers > &_fpioconst_pow10[0]);
exponent = exp10;
/* Optimize number representations. We want to represent the numbers
with the lowest number of bytes possible without losing any
bytes. Also the highest bit in the scaling factor has to be set
(this is a requirement of the MPN division routines). */
if (scalesize > 0)
{
/* Determine minimum number of zero bits at the end of
both numbers. */
for (i = 0; scale[i] == 0 && frac[i] == 0; i++)
;
/* Determine number of bits the scaling factor is misplaced. */
count_leading_zeros (cnt_h, scale[scalesize - 1]);
if (cnt_h == 0)
{
/* The highest bit of the scaling factor is already set. So
we only have to remove the trailing empty limbs. */
if (i > 0)
{
MPN_COPY_INCR (scale, scale + i, scalesize - i);
scalesize -= i;
MPN_COPY_INCR (frac, frac + i, fracsize - i);
fracsize -= i;
}
}
else
{
if (scale[i] != 0)
{
count_trailing_zeros (cnt_l, scale[i]);
if (frac[i] != 0)
{
int cnt_l2;
count_trailing_zeros (cnt_l2, frac[i]);
if (cnt_l2 < cnt_l)
cnt_l = cnt_l2;
}
}
else
count_trailing_zeros (cnt_l, frac[i]);
/* Now shift the numbers to their optimal position. */
if (i == 0 && BITS_PER_MP_LIMB - cnt_h > cnt_l)
{
/* We cannot save any memory. So just roll both numbers
so that the scaling factor has its highest bit set. */
(void) __mpn_lshift (scale, scale, scalesize, cnt_h);
cy = __mpn_lshift (frac, frac, fracsize, cnt_h);
if (cy != 0)
frac[fracsize++] = cy;
}
else if (BITS_PER_MP_LIMB - cnt_h <= cnt_l)
{
/* We can save memory by removing the trailing zero limbs
and by packing the non-zero limbs which gain another
free one. */
(void) __mpn_rshift (scale, scale + i, scalesize - i,
BITS_PER_MP_LIMB - cnt_h);
scalesize -= i + 1;
(void) __mpn_rshift (frac, frac + i, fracsize - i,
BITS_PER_MP_LIMB - cnt_h);
fracsize -= frac[fracsize - i - 1] == 0 ? i + 1 : i;
}
else
{
/* We can only save the memory of the limbs which are zero.
The non-zero parts occupy the same number of limbs. */
(void) __mpn_rshift (scale, scale + (i - 1),
scalesize - (i - 1),
BITS_PER_MP_LIMB - cnt_h);
scalesize -= i;
(void) __mpn_rshift (frac, frac + (i - 1),
fracsize - (i - 1),
BITS_PER_MP_LIMB - cnt_h);
fracsize -= frac[fracsize - (i - 1) - 1] == 0 ? i : i - 1;
}
}
}
}
else if (exponent < 0)
{
/* |FP| < 1.0. */
int exp10 = 0;
int explog = LDBL_MAX_10_EXP_LOG;
const struct mp_power *powers = &_fpioconst_pow10[explog + 1];
/* Now shift the input value to its right place. */
cy = __mpn_lshift (frac, fp_input, fracsize, to_shift);
frac[fracsize++] = cy;
assert (cy == 1 || (frac[fracsize - 2] == 0 && frac[0] == 0));
expsign = 1;
exponent = -exponent;
assert (powers != &_fpioconst_pow10[0]);
do
{
--powers;
if (exponent >= powers->m_expo)
{
int i, incr, cnt_h, cnt_l;
mp_limb_t topval[2];
/* The __mpn_mul function expects the first argument to be
bigger than the second. */
if (fracsize < powers->arraysize - _FPIO_CONST_OFFSET)
cy = __mpn_mul (tmp, &__tens[powers->arrayoff
+ _FPIO_CONST_OFFSET],
powers->arraysize - _FPIO_CONST_OFFSET,
frac, fracsize);
else
cy = __mpn_mul (tmp, frac, fracsize,
&__tens[powers->arrayoff + _FPIO_CONST_OFFSET],
powers->arraysize - _FPIO_CONST_OFFSET);
tmpsize = fracsize + powers->arraysize - _FPIO_CONST_OFFSET;
if (cy == 0)
--tmpsize;
count_leading_zeros (cnt_h, tmp[tmpsize - 1]);
incr = (tmpsize - fracsize) * BITS_PER_MP_LIMB
+ BITS_PER_MP_LIMB - 1 - cnt_h;
assert (incr <= powers->p_expo);
/* If we increased the exponent by exactly 3 we have to test
for overflow. This is done by comparing with 10 shifted
to the right position. */
if (incr == exponent + 3)
{
if (cnt_h <= BITS_PER_MP_LIMB - 4)
{
topval[0] = 0;
topval[1]
= ((mp_limb_t) 10) << (BITS_PER_MP_LIMB - 4 - cnt_h);
}
else
{
topval[0] = ((mp_limb_t) 10) << (BITS_PER_MP_LIMB - 4);
topval[1] = 0;
(void) __mpn_lshift (topval, topval, 2,
BITS_PER_MP_LIMB - cnt_h);
}
}
/* We have to be careful when multiplying the last factor.
If the result is greater than 1.0 be have to test it
against 10.0. If it is greater or equal to 10.0 the
multiplication was not valid. This is because we cannot
determine the number of bits in the result in advance. */
if (incr < exponent + 3
|| (incr == exponent + 3 &&
(tmp[tmpsize - 1] < topval[1]
|| (tmp[tmpsize - 1] == topval[1]
&& tmp[tmpsize - 2] < topval[0]))))
{
/* The factor is right. Adapt binary and decimal
exponents. */
exponent -= incr;
exp10 |= 1 << explog;
/* If this factor yields a number greater or equal to
1.0, we must not shift the non-fractional digits down. */
if (exponent < 0)
cnt_h += -exponent;
/* Now we optimize the number representation. */
for (i = 0; tmp[i] == 0; ++i);
if (cnt_h == BITS_PER_MP_LIMB - 1)
{
MPN_COPY (frac, tmp + i, tmpsize - i);
fracsize = tmpsize - i;
}
else
{
count_trailing_zeros (cnt_l, tmp[i]);
/* Now shift the numbers to their optimal position. */
if (i == 0 && BITS_PER_MP_LIMB - 1 - cnt_h > cnt_l)
{
/* We cannot save any memory. Just roll the
number so that the leading digit is in a
separate limb. */
cy = __mpn_lshift (frac, tmp, tmpsize, cnt_h + 1);
fracsize = tmpsize + 1;
frac[fracsize - 1] = cy;
}
else if (BITS_PER_MP_LIMB - 1 - cnt_h <= cnt_l)
{
(void) __mpn_rshift (frac, tmp + i, tmpsize - i,
BITS_PER_MP_LIMB - 1 - cnt_h);
fracsize = tmpsize - i;
}
else
{
/* We can only save the memory of the limbs which
are zero. The non-zero parts occupy the same
number of limbs. */
(void) __mpn_rshift (frac, tmp + (i - 1),
tmpsize - (i - 1),
BITS_PER_MP_LIMB - 1 - cnt_h);
fracsize = tmpsize - (i - 1);
}
}
}
}
--explog;
}
while (powers != &_fpioconst_pow10[1] && exponent > 0);
/* All factors but 10^-1 are tested now. */
if (exponent > 0)
{
int cnt_l;
cy = __mpn_mul_1 (tmp, frac, fracsize, 10);
tmpsize = fracsize;
assert (cy == 0 || tmp[tmpsize - 1] < 20);
count_trailing_zeros (cnt_l, tmp[0]);
if (cnt_l < MIN (4, exponent))
{
cy = __mpn_lshift (frac, tmp, tmpsize,
BITS_PER_MP_LIMB - MIN (4, exponent));
if (cy != 0)
frac[tmpsize++] = cy;
}
else
(void) __mpn_rshift (frac, tmp, tmpsize, MIN (4, exponent));
fracsize = tmpsize;
exp10 |= 1;
assert (frac[fracsize - 1] < 10);
}
exponent = exp10;
}
else
{
/* This is a special case. We don't need a factor because the
numbers are in the range of 1.0 <= |fp| < 8.0. We simply
shift it to the right place and divide it by 1.0 to get the
leading digit. (Of course this division is not really made.) */
assert (0 <= exponent && exponent < 3 &&
exponent + to_shift < BITS_PER_MP_LIMB);
/* Now shift the input value to its right place. */
cy = __mpn_lshift (frac, fp_input, fracsize, (exponent + to_shift));
frac[fracsize++] = cy;
exponent = 0;
}
{
int width = info->width;
wchar_t *wstartp, *wcp;
size_t chars_needed;
int expscale;
int intdig_max, intdig_no = 0;
int fracdig_min;
int fracdig_max;
int dig_max;
int significant;
int ngroups = 0;
char spec = _tolower (info->spec);
if (spec == 'e')
{
type = info->spec;
intdig_max = 1;
fracdig_min = fracdig_max = info->prec < 0 ? 6 : info->prec;
chars_needed = 1 + 1 + (size_t) fracdig_max + 1 + 1 + 4;
/* d . ddd e +- ddd */
dig_max = INT_MAX; /* Unlimited. */
significant = 1; /* Does not matter here. */
}
else if (spec == 'f')
{
type = 'f';
fracdig_min = fracdig_max = info->prec < 0 ? 6 : info->prec;
dig_max = INT_MAX; /* Unlimited. */
significant = 1; /* Does not matter here. */
if (expsign == 0)
{
intdig_max = exponent + 1;
/* This can be really big! */ /* XXX Maybe malloc if too big? */
chars_needed = (size_t) exponent + 1 + 1 + (size_t) fracdig_max;
}
else
{
intdig_max = 1;
chars_needed = 1 + 1 + (size_t) fracdig_max;
}
}
else
{
dig_max = info->prec < 0 ? 6 : (info->prec == 0 ? 1 : info->prec);
if ((expsign == 0 && exponent >= dig_max)
|| (expsign != 0 && exponent > 4))
{
if ('g' - 'G' == 'e' - 'E')
type = 'E' + (info->spec - 'G');
else
type = isupper (info->spec) ? 'E' : 'e';
fracdig_max = dig_max - 1;
intdig_max = 1;
chars_needed = 1 + 1 + (size_t) fracdig_max + 1 + 1 + 4;
}
else
{
type = 'f';
intdig_max = expsign == 0 ? exponent + 1 : 0;
fracdig_max = dig_max - intdig_max;
/* We need space for the significant digits and perhaps
for leading zeros when < 1.0. The number of leading
zeros can be as many as would be required for
exponential notation with a negative two-digit
exponent, which is 4. */
chars_needed = (size_t) dig_max + 1 + 4;
}
fracdig_min = info->alt ? fracdig_max : 0;
significant = 0; /* We count significant digits. */
}
if (grouping)
{
/* Guess the number of groups we will make, and thus how
many spaces we need for separator characters. */
ngroups = __guess_grouping (intdig_max, grouping);
/* Allocate one more character in case rounding increases the
number of groups. */
chars_needed += ngroups + 1;
}
/* Allocate buffer for output. We need two more because while rounding
it is possible that we need two more characters in front of all the
other output. If the amount of memory we have to allocate is too
large use `malloc' instead of `alloca'. */
if (__builtin_expect (chars_needed >= (size_t) -1 / sizeof (wchar_t) - 2
|| chars_needed < fracdig_max, 0))
{
/* Some overflow occurred. */
__set_errno (ERANGE);
return -1;
}
size_t wbuffer_to_alloc = (2 + chars_needed) * sizeof (wchar_t);
buffer_malloced = ! __libc_use_alloca (wbuffer_to_alloc);
if (__builtin_expect (buffer_malloced, 0))
{
wbuffer = (wchar_t *) malloc (wbuffer_to_alloc);
if (wbuffer == NULL)
/* Signal an error to the caller. */
return -1;
}
else
wbuffer = (wchar_t *) alloca (wbuffer_to_alloc);
wcp = wstartp = wbuffer + 2; /* Let room for rounding. */
/* Do the real work: put digits in allocated buffer. */
if (expsign == 0 || type != 'f')
{
assert (expsign == 0 || intdig_max == 1);
while (intdig_no < intdig_max)
{
++intdig_no;
*wcp++ = hack_digit ();
}
significant = 1;
if (info->alt
|| fracdig_min > 0
|| (fracdig_max > 0 && (fracsize > 1 || frac[0] != 0)))
*wcp++ = decimalwc;
}
else
{
/* |fp| < 1.0 and the selected type is 'f', so put "0."
in the buffer. */
*wcp++ = L'0';
--exponent;
*wcp++ = decimalwc;
}
/* Generate the needed number of fractional digits. */
int fracdig_no = 0;
int added_zeros = 0;
while (fracdig_no < fracdig_min + added_zeros
|| (fracdig_no < fracdig_max && (fracsize > 1 || frac[0] != 0)))
{
++fracdig_no;
*wcp = hack_digit ();
if (*wcp++ != L'0')
significant = 1;
else if (significant == 0)
{
++fracdig_max;
if (fracdig_min > 0)
++added_zeros;
}
}
/* Do rounding. */
wchar_t last_digit = wcp[-1] != decimalwc ? wcp[-1] : wcp[-2];
wchar_t next_digit = hack_digit ();
bool more_bits;
if (next_digit != L'0' && next_digit != L'5')
more_bits = true;
else if (fracsize == 1 && frac[0] == 0)
/* Rest of the number is zero. */
more_bits = false;
else if (scalesize == 0)
{
/* Here we have to see whether all limbs are zero since no
normalization happened. */
size_t lcnt = fracsize;
while (lcnt >= 1 && frac[lcnt - 1] == 0)
--lcnt;
more_bits = lcnt > 0;
}
else
more_bits = true;
int rounding_mode = get_rounding_mode ();
if (round_away (is_neg, (last_digit - L'0') & 1, next_digit >= L'5',
more_bits, rounding_mode))
{
wchar_t *wtp = wcp;
if (fracdig_no > 0)
{
/* Process fractional digits. Terminate if not rounded or
radix character is reached. */
int removed = 0;
while (*--wtp != decimalwc && *wtp == L'9')
{
*wtp = L'0';
++removed;
}
if (removed == fracdig_min && added_zeros > 0)
--added_zeros;
if (*wtp != decimalwc)
/* Round up. */
(*wtp)++;
else if (__builtin_expect (spec == 'g' && type == 'f' && info->alt
&& wtp == wstartp + 1
&& wstartp[0] == L'0',
0))