glibc/misc/efgcvt_r.c

93 lines
2.2 KiB
C

/* [efg]cvt -- compatibility functions for floating point formatting,
reentrent versions.
Copyright (C) 1995, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
int
fcvt_r (value, ndigit, decpt, sign, buf, len)
double value;
int ndigit, *decpt, *sign;
char *buf;
size_t len;
{
int n, i;
if (buf == NULL)
{
errno = EINVAL;
return -1;
}
*sign = value < 0.0;
if (*sign)
value = - value;
n = snprintf (buf, len, "%.*f", ndigit, value);
if (n < 0)
return -1;
i = 0;
while (i < n && isdigit (buf[i]))
++i;
*decpt = i;
do
++i;
while (! isdigit (buf[i]));
memmove (&buf[i - *decpt], buf, n - (i - *decpt));
return 0;
}
weak_extern (floor) weak_extern (log10) weak_extern (fabs)
int
ecvt_r (value, ndigit, decpt, sign, buf, len)
double value;
int ndigit, *decpt, *sign;
char *buf;
size_t len;
{
double (*log10_function) (double) = &log10;
if (log10_function)
{
/* Use the reasonable code if -lm is included. */
ndigit -= (int) floor (log10 (fabs (value)));
if (ndigit < 0)
ndigit = 0;
}
else
{
/* Slow code that doesn't require -lm functions. */
double d;
for (d = value < 0.0 ? - value : value;
ndigit > 0 && d >= 10.0;
d *= 0.1)
--ndigit;
}
return fcvt_r (value, ndigit, decpt, sign, buf, len);
}