156 lines
3.4 KiB
C
156 lines
3.4 KiB
C
/* Compatibility functions for floating point formatting, reentrant versions.
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Copyright (C) 1995, 1996, 1997 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <errno.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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#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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#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 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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int n, i;
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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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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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}
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n = snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", ndigit, value);
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if (n < 0)
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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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{
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/* Value is Inf or NaN. */
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*sign = 0;
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return 0;
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}
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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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memmove (&buf[*decpt], &buf[i], n - i);
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buf[n - (i - *decpt)] = 0;
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}
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return 0;
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}
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#define weak_extern2(name) weak_extern (name)
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weak_extern2 (FLOOR) weak_extern2 (LOG10) weak_extern2 (FABS)
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weak_extern2 (EXP)
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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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FLOAT_TYPE (*log10_function) (FLOAT_TYPE) = &LOG10;
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if (log10_function)
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{
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/* Use the reasonable code if -lm is included. */
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FLOAT_TYPE dexponent;
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dexponent = FLOOR (LOG10 (FABS (value)));
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value *= EXP (dexponent * -M_LN10);
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exponent = (int) dexponent;
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}
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else
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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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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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if (d < 1.0)
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{
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do
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{
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d *= 10.0;
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exponent--;
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}
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while (d < 1.0);
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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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d *= 0.1;
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exponent++;
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}
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while (d >= 10.0);
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}
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if (value < 0.0)
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value = -d;
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else
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value = d;
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}
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}
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if (APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit - 1, 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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