266 lines
6.1 KiB
C
266 lines
6.1 KiB
C
/* Compatibility functions for floating point formatting, reentrant versions.
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Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2006
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Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <errno.h>
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#include <float.h>
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include <math.h>
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#include <stdlib.h>
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#include <sys/param.h>
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#include <math_ldbl_opt.h>
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#ifndef FLOAT_TYPE
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# define FLOAT_TYPE double
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# define FUNC_PREFIX
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# define FLOAT_FMT_FLAG
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# define FLOAT_NAME_EXT
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# define FLOAT_MIN_10_EXP DBL_MIN_10_EXP
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# if DBL_MANT_DIG == 53
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# define NDIGIT_MAX 17
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# elif DBL_MANT_DIG == 24
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# define NDIGIT_MAX 9
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# elif DBL_MANT_DIG == 56
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# define NDIGIT_MAX 18
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# else
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/* See IEEE 854 5.6, table 2 for this formula. Unfortunately we need a
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compile time constant here, so we cannot use it. */
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# error "NDIGIT_MAX must be precomputed"
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# define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
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# endif
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# if DBL_MIN_10_EXP == -37
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# define FLOAT_MIN_10_NORM 1.0e-37
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# elif DBL_MIN_10_EXP == -307
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# define FLOAT_MIN_10_NORM 1.0e-307
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# elif DBL_MIN_10_EXP == -4931
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# define FLOAT_MIN_10_NORM 1.0e-4931
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# else
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/* libc can't depend on libm. */
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# error "FLOAT_MIN_10_NORM must be precomputed"
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# define FLOAT_MIN_10_NORM exp10 (DBL_MIN_10_EXP)
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# endif
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#else
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# define LONG_DOUBLE_CVT
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#endif
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#define APPEND(a, b) APPEND2 (a, b)
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#define APPEND2(a, b) a##b
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#define __APPEND(a, b) __APPEND2 (a, b)
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#define __APPEND2(a, b) __##a##b
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#define FLOOR APPEND(floor, FLOAT_NAME_EXT)
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#define FABS APPEND(fabs, FLOAT_NAME_EXT)
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#define LOG10 APPEND(log10, FLOAT_NAME_EXT)
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#define EXP APPEND(exp, FLOAT_NAME_EXT)
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int
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__APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign, buf, len)
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FLOAT_TYPE value;
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int ndigit, *decpt, *sign;
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char *buf;
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size_t len;
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{
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ssize_t n;
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ssize_t i;
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int left;
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if (buf == NULL)
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{
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__set_errno (EINVAL);
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return -1;
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}
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left = 0;
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if (isfinite (value))
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{
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*sign = signbit (value) != 0;
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if (*sign)
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value = -value;
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if (ndigit < 0)
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{
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/* Rounding to the left of the decimal point. */
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while (ndigit < 0)
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{
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FLOAT_TYPE new_value = value * 0.1;
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if (new_value < 1.0)
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{
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ndigit = 0;
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break;
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}
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value = new_value;
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++left;
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++ndigit;
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}
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}
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}
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else
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/* Value is Inf or NaN. */
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*sign = 0;
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n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX),
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value);
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/* Check for a too small buffer. */
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if (n >= (ssize_t) len)
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return -1;
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i = 0;
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while (i < n && isdigit (buf[i]))
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++i;
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*decpt = i;
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if (i == 0)
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/* Value is Inf or NaN. */
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return 0;
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if (i < n)
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{
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do
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++i;
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while (i < n && !isdigit (buf[i]));
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if (*decpt == 1 && buf[0] == '0' && value != 0.0)
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{
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/* We must not have leading zeroes. Strip them all out and
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adjust *DECPT if necessary. */
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--*decpt;
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while (i < n && buf[i] == '0')
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{
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--*decpt;
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++i;
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}
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}
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memmove (&buf[MAX (*decpt, 0)], &buf[i], n - i);
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buf[n - (i - MAX (*decpt, 0))] = '\0';
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}
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if (left)
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{
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*decpt += left;
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if ((ssize_t) --len > n)
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{
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while (left-- > 0 && n < (ssize_t) len)
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buf[n++] = '0';
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buf[n] = '\0';
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}
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}
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return 0;
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}
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int
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__APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign, buf, len)
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FLOAT_TYPE value;
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int ndigit, *decpt, *sign;
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char *buf;
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size_t len;
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{
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int exponent = 0;
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if (isfinite (value) && value != 0.0)
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{
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/* Slow code that doesn't require -lm functions. */
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FLOAT_TYPE d;
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FLOAT_TYPE f = 1.0;
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if (value < 0.0)
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d = -value;
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else
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d = value;
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/* For denormalized numbers the d < 1.0 case below won't work,
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as f can overflow to +Inf. */
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if (d < FLOAT_MIN_10_NORM)
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{
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value /= FLOAT_MIN_10_NORM;
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if (value < 0.0)
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d = -value;
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else
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d = value;
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exponent += FLOAT_MIN_10_EXP;
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}
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if (d < 1.0)
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{
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do
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{
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f *= 10.0;
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--exponent;
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}
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while (d * f < 1.0);
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value *= f;
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}
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else if (d >= 10.0)
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{
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do
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{
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f *= 10;
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++exponent;
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}
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while (d >= f * 10.0);
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value /= f;
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}
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}
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else if (value == 0.0)
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/* SUSv2 leaves it unspecified whether *DECPT is 0 or 1 for 0.0.
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This could be changed to -1 if we want to return 0. */
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exponent = 0;
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if (ndigit <= 0 && len > 0)
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{
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buf[0] = '\0';
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*decpt = 1;
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*sign = isfinite (value) ? signbit (value) != 0 : 0;
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}
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else
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if (__APPEND (FUNC_PREFIX, fcvt_r) (value, MIN (ndigit, NDIGIT_MAX) - 1,
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decpt, sign, buf, len))
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return -1;
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*decpt += exponent;
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return 0;
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}
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#if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
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# ifdef LONG_DOUBLE_CVT
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# define cvt_symbol(symbol) \
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cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
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APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
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# define cvt_symbol_1(lib, local, symbol, version) \
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versioned_symbol (lib, local, symbol, version)
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# else
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# define cvt_symbol(symbol) \
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cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
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APPEND (q, symbol), GLIBC_2_0); \
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strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
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# define cvt_symbol_1(lib, local, symbol, version) \
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compat_symbol (lib, local, symbol, version)
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# endif
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#else
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# define cvt_symbol(symbol) \
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strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
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#endif
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cvt_symbol(fcvt_r);
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cvt_symbol(ecvt_r);
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