mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-08 22:30:07 +00:00
b113c12c35
1999-07-28 Ulrich Drepper <drepper@cygnus.com> * misc/efgcvt.c: Use IEEE 854 formula to compute the number of digits to print. * misc/efgcvt_r.c: Likewise. * misc/qefgcvt.c: Likewise. * misc/qefgcvt_r.c: Likewise. * misc/tst-efgcvt.c: Remove one test which cannot reliably be run anymore.
86 lines
2.4 KiB
C
86 lines
2.4 KiB
C
/* Compatibility functions for floating point formatting.
|
|
Copyright (C) 1995, 1996, 1997, 1999 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 <math.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <sys/param.h>
|
|
#include <float.h>
|
|
#include <bits/libc-lock.h>
|
|
|
|
#ifndef FLOAT_TYPE
|
|
# define FLOAT_TYPE double
|
|
# define FUNC_PREFIX
|
|
# define FLOAT_FMT_FLAG
|
|
/* Actually we have to write (DBL_DIG + log10 (DBL_MAX_10_EXP)) but we
|
|
don't have log10 available in the preprocessor. */
|
|
# define MAXDIG (NDIGIT_MAX + 3)
|
|
# if DBL_MANT_DIG == 53
|
|
# define NDIGIT_MAX 17
|
|
# else
|
|
/* See IEEE 854 5.6, table 2 for this formula. */
|
|
# define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
|
|
# endif
|
|
#endif
|
|
|
|
#define APPEND(a, b) APPEND2 (a, b)
|
|
#define APPEND2(a, b) a##b
|
|
|
|
|
|
#define FCVT_BUFFER APPEND (FUNC_PREFIX, fcvt_buffer)
|
|
#define ECVT_BUFFER APPEND (FUNC_PREFIX, ecvt_buffer)
|
|
|
|
|
|
static char FCVT_BUFFER[MAXDIG];
|
|
static char ECVT_BUFFER[MAXDIG];
|
|
|
|
|
|
char *
|
|
APPEND (FUNC_PREFIX, fcvt) (value, ndigit, decpt, sign)
|
|
FLOAT_TYPE value;
|
|
int ndigit, *decpt, *sign;
|
|
{
|
|
(void) APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
|
|
FCVT_BUFFER, MAXDIG);
|
|
|
|
return FCVT_BUFFER;
|
|
}
|
|
|
|
|
|
char *
|
|
APPEND (FUNC_PREFIX, ecvt) (value, ndigit, decpt, sign)
|
|
FLOAT_TYPE value;
|
|
int ndigit, *decpt, *sign;
|
|
{
|
|
(void) APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign,
|
|
ECVT_BUFFER, MAXDIG);
|
|
|
|
return ECVT_BUFFER;
|
|
}
|
|
|
|
char *
|
|
APPEND (FUNC_PREFIX, gcvt) (value, ndigit, buf)
|
|
FLOAT_TYPE value;
|
|
int ndigit;
|
|
char *buf;
|
|
{
|
|
sprintf (buf, "%.*" FLOAT_FMT_FLAG "g", MIN (ndigit, NDIGIT_MAX), value);
|
|
return buf;
|
|
}
|