glibc/misc/efgcvt.c

92 lines
2.6 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
# elif DBL_MANT_DIG == 24
# define NDIGIT_MAX 9
# elif DBL_MANT_DIG == 56
# define NDIGIT_MAX 18
# else
/* See IEEE 854 5.6, table 2 for this formula. Unfortunately we need a
compile time constant here, so we cannot use it. */
# error "NDIGIT_MAX must be precomputed"
# 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;
}